JP2024518985A - Systems and methods for processing ammonia - Google Patents

Abstract

The present disclosure provides systems and methods for processing ammonia. The systems may include one or more reactor modules configured to produce hydrogen from a feed material including ammonia. The hydrogen produced by the one or more reactor modules may be used to provide additional heating for the reactor modules (e.g., by combustion of the hydrogen) or may be supplied to one or more fuel cells for the production of electrical energy. Illustrated in FIG.

Description

CROSS REFERENCE This application claims priority to U.S. Provisional Patent Application No. 63/188,593, filed May 14, 2021, No. 63/215,843, filed June 28, 2021, No. 63/236,048, filed August 23, 2021, No. 63/247,054, filed September 22, 2021, No. 63/292,122, filed December 21, 2021, U.S. Patent Application No. 17/366,633, filed July 2, 2021, and No. 17/401,993, filed August 13, 2021, the contents of each of which are incorporated by reference herein in their entirety for all purposes.

Fuel sources can be used to operate a variety of systems. A fuel source can have a specific energy that corresponds to the amount of energy that can be stored or extracted per unit mass of fuel. Fuel sources can be provided to a variety of systems to enable such systems to generate energy and/or provide power (e.g., for travel or transportation).

Hydrogen can be utilized as a clean energy source to power a variety of systems. Hydrogen can provide distinct advantages over other types of fuels, such as diesel, gasoline, or jet fuel, which have a specific energy of about 45 megajoules per kilogram (MJ/kg) (heat), or lithium-ion batteries, which have a specific energy of about 0.95 MJ/kg (electricity). In contrast, hydrogen has a specific energy (heat) of over 140 MJ/kg. Thus, 1 kg of hydrogen can produce the same amount of energy as about 3 kg of gasoline or kerosene. Thus, hydrogen as a fuel source can help reduce the amount of fuel (by mass) required to produce an equivalent amount of energy as other conventional fuel sources. Furthermore, systems that use hydrogen as a fuel source (e.g., as a combustion reactant) generally produce benign or non-toxic by-products, such as water, while minimizing or nearly eliminating greenhouse gas (e.g., carbon dioxide and nitrous oxide) emissions, thereby reducing the environmental impact of various systems (e.g., transportation) that use hydrogen as a fuel source.

Various limitations of currently available hydrogen storage and production systems are recognized herein. Although hydrogen has a relatively high gravimetric density (measured in MJ/kg), fuel storage systems for compressed and liquefied hydrogen are often complicated due to the need to provide and maintain specialized storage conditions. For example, storage of hydrogen as a gas would require high-pressure tanks (e.g., 350-700 bar or 5,000-10,000 psi). Storage of hydrogen as a liquid would require extremely low temperatures, since the boiling point of hydrogen at 1 atmosphere is −252.8° C. Further recognized herein are various limitations with commercially available ammonia processing systems, which generally have slow start-up times, non-ideal thermal properties, suboptimal ammonia conversion efficiencies, and high weight and volume requirements.

The present disclosure provides systems and methods that address at least the above-mentioned shortcomings of conventional systems for processing ammonia to make, store, and/or release hydrogen for use as a fuel source (e.g., in a fueling station or power generation system). Embodiments of the present disclosure generally relate to systems and methods for processing a feedstock material to make or extract a fuel source. The fuel source may include hydrogen. The feedstock material may include any material or compound that includes hydrogen (e.g., a hydrocarbon). In some cases, the feedstock material may include ammonia ( _NH3 ).

The present system and method are advantageous in several ways. Some embodiments of the present system and method enable decarbonization (e.g., using ammonia as a feedstock and hydrogen as a fuel source) of long-distance shipping (e.g., trucking routes over 500 miles or transoceanic shipping routes) that are difficult to refuel with other decarbonization methods. On such long-distance routes, using batteries to power the motors may require excessively long charging times and excessive weight and volume requirements, reducing the space available for cargo and therefore reducing the revenue of the ship operator. Furthermore, using only hydrogen (e.g., stored as pure hydrogen and not converted from ammonia) on such long-distance routes may be infeasible due to the special storage conditions of hydrogen mentioned above and the requirement for large storage tanks. Thus, some embodiments of the present system and method can generate high power (5 kilowatts or more) while having high energy density (655 Wh/kg or more by weight, 447 Wh/L or more by volume) when utilizing ammonia as a feedstock and hydrogen as a fuel source.

Additionally, some embodiments of the reactors in the present disclosure can be heated by combustion of hydrogen extracted from ammonia (as opposed to heating the reactor by burning hydrocarbons or ammonia, which can undesirably emit greenhouse gases, nitrogen oxides ( _NOx ), and/or particulate matter). In some embodiments, decomposing or cracking ammonia into hydrogen can eliminate the need for separate tanks to store combustion fuels (e.g., hydrocarbons, hydrogen, or ammonia) for heating the reactor modules of the present disclosure.

Additionally, some embodiments of the present system and method can take advantage of the high ammonia conversion efficiency of the adsorber (achieved by the reactor and catalyst design of the present disclosure) to remove unconverted ammonia, thereby providing a highly purified hydrogen stream (e.g., 99% or greater purity) or a hydrogen stream mixed with nitrogen containing trace ammonia (e.g., less than 1 ppm). In some embodiments, the high purity hydrogen (or hydrogen mixed with nitrogen) stream can be consumed by a proton exchange membrane fuel cell (PEMFC) or other power generation device (e.g., internal combustion engine [ICE] or solid oxide fuel cell [SOFC]).

Furthermore, the systems and methods of the present invention are simple to operate and can provide a high degree of safety. In some embodiments, ammonia can be introduced using a single inlet from the ammonia tank (as opposed to, for example, a first inlet for the first reactor module, a second inlet for the second reactor module, etc.). In some embodiments, a single flow of ammonia passes through all reactor modules (e.g., first through the start-up reactor and then into the main reactor, or vice versa). In some embodiments, this configuration can transfer excess heat (which promotes vaporization of liquid ammonia) from the reactor modules to the ammonia input from the storage tank, ensuring sufficiently high ammonia conversion efficiency. In some embodiments, the ammonia flow rate can be controlled by the single inlet, and in the event of a major failure or hazardous event, the ammonia flow rate can be quickly shut off by the single inlet.

In one aspect, the disclosure provides a system for processing ammonia. The system includes a first reactor module configured to receive a feed material including ammonia, the first reactor module including (i) a first catalyst and (ii) a start-up heating and reforming unit, the start-up heating and reforming unit including one or more electrodes for applying an electric current to the first catalyst to heat the first catalyst, the first catalyst configured to make or extract hydrogen from ammonia when the first catalyst is heated using the start-up heating and reforming unit, and a second reactor module in fluid communication with the first reactor module, the second reactor module configured to receive a feed material including ammonia, the second reactor module including (i) a second catalyst and (ii) one or more main heating units for heating the second catalyst, at least one of the one or more main heating units configured to heat at least a portion of the second catalyst by burning hydrogen produced by the first reactor module, the second catalyst configured to make or extract hydrogen from ammonia when the second catalyst is heated using the one or more main heating units.

In some embodiments, the one or more ammonia fuel sources include one or more liquid fuel storage tanks, and the ammonia is stored as liquid ammonia in the one or more liquid fuel storage tanks.

In some embodiments, the liquid ammonia is stored at a temperature in the range of about 15 to about 30° C. and at an absolute pressure in the range of 7 to 12 bar. In some embodiments, the liquid ammonia is stored at a gauge pressure in the range of about atmospheric pressure to about 20 bar. In some embodiments, the liquid ammonia is stored at a temperature in the range of about -40 to about 20° C. and at an absolute pressure in the range of about 0.5 bar to about 9 bar.

In some embodiments, the one or more main heating units comprise an electric heater or a fired heater. In some embodiments, the one or more electrodes include one or more metal electrodes. In some embodiments, the one or more metal electrodes may include copper.

In some embodiments, at least one of the first catalyst and the second catalyst comprises a metal foam catalyst. In some embodiments, the metal foam catalyst comprises nickel, iron, chromium, cobalt, molybdenum, copper, or aluminum. In some embodiments, the metal foam catalyst comprises one or more alloys comprising nickel, iron, chromium, cobalt, molybdenum, copper, or aluminum. In some embodiments, the metal foam catalyst comprises a catalyst coating of one or more powder or pellet catalysts. In some embodiments, the catalyst coating comprises a metal material, a promoter material, a support material, or any combination thereof. In some embodiments, the metal material comprises ruthenium, nickel, rhodium, iridium, cobalt, iron, platinum, chromium, palladium, or copper. In some embodiments, the promoter material comprises at least one material selected from Li, Na, K, Rb, Cs, Mg, Ca, Ba, Sr, La, Ce, Pr, Sm, or Gd. In some embodiments, the support comprises _{at least} one material selected from _Al2O3 , MgO, _CeO2 , _{ZrO2, La2O3 , SiO2} , _Y2O3 , _TiO2 , SiC, hexagonal BN (boron nitride ₎ , BN nanotubes, silicon carbide, one or more zeolites _{, LaAlO3} , _CeAlO3 , _{MgAl2O4 , CaAl2O4} , or one or more carbon nanotubes.

In some embodiments, the catalyst coating comprises one or more ruthenium-based precursors. In some embodiments, the one or more ruthenium-based precursors comprise _RuCl3 or _Ru3 (CO) ₁₂ . In some embodiments, the metal foam catalyst has an apparent electrical resistivity of at least about 8 microohm-meters (μΩm). In some embodiments, the metal foam catalyst can be treated using one or more of etching, leaching, or acid treatment to increase the surface area of the metal foam catalyst. In some embodiments, the metal foam catalyst is heat treated and heat activated. In some embodiments, the metal foam catalyst is coated using a physical vapor deposition process or a chemical vapor deposition process.

In some embodiments, the first reactor module comprises a plurality of modular units stackable together. In some embodiments, each of the plurality of modular units comprises a metal foam catalyst and one or more reactor flow paths for directing ammonia to the metal foam catalyst. In some embodiments, the system may further comprise one or more insulating panels for separating the plurality of modular units, the one or more insulating panels comprising an electrically insulating coating, the electrically insulating coating disposed between the plurality of modular units.

In some embodiments, hydrogen produced using the first reactor module can be used to power one or more fuel cells or heat the second reactor module by combustion. In some embodiments, the first reactor module has a start-up time of up to about 5 minutes to reach a target temperature of at least about 550 degrees Celsius. In some embodiments, the first reactor module has a start-up time of up to about 60 minutes to reach a target temperature of at least about 550 degrees Celsius. In some embodiments, the first reactor module provides an ammonia conversion efficiency of at least about 90%. In some embodiments, the first reactor module has a power density of about 10 watts per cubic centimeter of reactor bed volume. In some embodiments, the system has a system level electrical energy density of at least about 600 watt-hours per kilogram. In some embodiments, the system has a hydrogen storage capacity of at least about 5% by weight. In some embodiments, at least one of the first reactor module and the second reactor module is configured for self-heating by electricity or hydrogen combustion.

In some embodiments, the system may further include one or more fuel cells in fluid communication with at least one of the first reactor module and the second reactor module. In some embodiments, the system may further include a hybrid battery for load following and initial reactor heating power. In some embodiments, the hybrid battery is in electrical communication with at least one of the first reactor module and the second reactor module.

In some embodiments, the second reactor module is in fluid communication with the first reactor module to allow transport of hydrogen, nitrogen, or ammonia between the first reactor module and the second reactor module. In some embodiments, the second reactor module is in thermal and/or fluid communication with the first reactor module. In some embodiments, the feed material is supplied to the first reactor module and the second reactor module from the same feed. In some embodiments, the feed material is supplied to the first reactor module and the second reactor module from different sources.

In some embodiments, the system may further include one or more springs adjacent to the catalyst and/or the one or more electrodes, the one or more springs configured to relieve or redistribute mechanical loads on the catalyst when the catalyst undergoes one or more thermal cycling procedures. In some embodiments, the one or more springs include one or more metal springs. In some embodiments, the one or more springs include one or more copper springs. In some embodiments, the one or more springs are configured to relieve thermal stresses on the catalyst due to thermal expansion or contraction of the catalyst during one or more thermal cycling procedures.

In another aspect, the present disclosure provides a method for processing ammonia, the method including: (a) providing (i) a first reactor module including a first catalyst and a start-up heating and reforming unit, and (ii) a second reactor module in fluid communication with the first reactor module, the second reactor module including a second catalyst and one or more main heating units; (b) using the start-up heating and reforming unit to pass an electric current through the first catalyst to heat the first catalyst, the first catalyst being configured to make or extract hydrogen from ammonia when heated; and (c) using at least one of the one or more main heating units to heat at least a portion of the second catalyst by burning hydrogen produced using the first reactor module and/or the second reactor module.

In some embodiments, the method further includes using a second catalyst to make or extract hydrogen from the ammonia, the second catalyst configured to make or extract hydrogen from the ammonia when heated. In some embodiments, the method can further include directing at least a portion of the hydrogen produced using the second catalyst to one or more fuel cells to generate electrical energy. In some embodiments, the method can further include directing at least a portion of the hydrogen produced using the first catalyst to one or more fuel cells to generate electrical energy.

In another aspect, the disclosure provides a system, the system comprising: a reactor module configured to receive a feed material including ammonia, the reactor module comprising a catalyst and a plurality of heating units for heating the catalyst, the plurality of heating units comprising a first heating unit configured to heat at least a first portion of the catalyst by combustion and a second heating unit configured to heat at least a second portion of the catalyst using electrical heating, the catalyst configured to make or extract hydrogen from ammonia when the catalyst is heated using the plurality of heating units.

In some embodiments, the second heating unit is configured to heat the second portion of the catalyst by passing an electric current through the second portion of the catalyst. In some embodiments, the system may further include a second reactor module in fluid and/or thermal communication with the reactor module, the second reactor module including a second catalyst and a second heating unit, the second heating unit configured to heat the second catalyst, and the second catalyst configured to make or extract hydrogen from ammonia when the second catalyst is heated using the second heating unit.

In some embodiments, the first heating unit of the reactor module is configured to heat the first portion of the catalyst by burning hydrogen gas produced using the second reactor module. In some embodiments, the first heating unit is configured to heat the first portion of the catalyst by burning residual hydrogen gas from one or more fuel cells in fluid communication with the reactor module or the second reactor module. In some embodiments, the second heating unit comprises one or more electrodes for passing an electric current through the second catalyst to heat the second catalyst.

In some embodiments, the heat load distribution between the first heating unit and the second heating unit is adjustable to increase ammonia cracking conversion efficiency and improve thermal reforming efficiency of the reactor module. In some embodiments, the system may further include a controller configured to control operation of the first heating unit and the second heating unit to adjust the heat load distribution in the reactor module. In some embodiments, the heat load distribution includes a heating power ratio corresponding to a ratio between the heating power of the first heating unit and the heating power of the second heating unit.

In some embodiments, the reactor module has a thermal reforming efficiency of at least about 80%. In some embodiments, the reactor module has a thermal reforming efficiency of at least about 90%. In some embodiments, the reactor module has a thermal reforming efficiency of at least about 95%. In some embodiments, the reactor module comprises a cartridge heater design utilizing one or more electrically insulating materials with a high heat transfer coefficient. In some embodiments, the one or more electrically insulating materials comprise boron nitride. In some embodiments, the reactor module comprises a reaction bed comprising one or more ammonia decomposition catalysts comprising a metallic material, a promoter material, and a support material. In some embodiments, the first heating unit and the second heating unit are configured to heat different portions of the reaction bed. In some embodiments, the metallic material comprises ruthenium, nickel, rhodium, iridium, cobalt, iron, platinum, chromium, palladium, or copper. In some embodiments, the promoter material comprises at least one material selected from Li, Na, K, Rb, Cs, Mg, Ca, Ba, Sr, La, Ce, Pr, Sm, or Gd. In some embodiments, the support comprises _{at least} one material selected from _Al2O3 , MgO, _CeO2 , _{ZrO2, La2O3 , SiO2} , _Y2O3 , _TiO2 , SiC, hexagonal BN (boron nitride ₎ , BN nanotubes, silicon carbide, one or more zeolites _{, LaAlO3} , _CeAlO3 , _{MgAl2O4 , CaAl2O4} , or one or more carbon nanotubes.

In some embodiments, the reactor module includes one or more walls having a thickness in the range of about 0.5 millimeters to about 1.5 millimeters to reduce thermal mass and provide faster and more dynamic temperature response. In some embodiments, the reactor module includes one or more walls having a thickness in the range of about 1.5 millimeters to about 10 millimeters (to increase structural integrity). In some embodiments, the system may further include one or more fuel cells in fluid communication with the reactor module, the one or more fuel cells configured to generate electrical energy using hydrogen produced by the reactor module.

In some embodiments, the plurality of heating units comprises at least two or more heating units. In some embodiments, the heat load distribution between the at least two or more heating units is adjustable to increase ammonia conversion efficiency and to improve thermal reforming efficiency of the reactor module. In some embodiments, each of the at least two or more heating units has one or more heating zones within the reactor module to enable continuous heat distribution within one or more regions within the reactor module. In some embodiments, the at least two or more heating units are configured to heat different heating zones within the reactor module. In some embodiments, the at least two or more heating units are configured to heat one or more of the same zones within the reactor module. In some embodiments, the first portion and the second portion are different portions of the catalyst. In some embodiments, the electrical heating includes Joule heating.

In another aspect, the disclosure provides a method, the method including: (a) providing a reactor module comprising a catalyst and a plurality of heating units for heating the catalyst, the plurality of heating units comprising a first heating unit and a second heating unit, the catalyst configured to make or extract hydrogen from ammonia when the catalyst is heated using the plurality of heating units; and (b) using (i) the first heating unit to heat at least a first portion of the catalyst by combustion and (ii) the second heating unit to heat at least a second portion of the catalyst by electrical heating.

In some embodiments, the method may further include extracting hydrogen from the ammonia using a catalyst. In some embodiments, the method may further include directing the extracted hydrogen to one or more fuel cells to generate electrical energy. In some embodiments, heating at least a first portion of the catalyst using a first heating unit includes combusting hydrogen gas produced using a second reactor module. In some embodiments, heating at least a second portion of the catalyst using a second heating unit includes passing an electric current through a second portion of the catalyst. In some embodiments, the method may further include adjusting a heat load distribution between the first heating unit and the second heating unit to increase ammonia conversion efficiency and improve thermal reforming efficiency of the reactor module.

In another aspect, the present disclosure provides a system for processing ammonia, the system comprising one or more reactors for decomposing ammonia using one or more catalysts, one or more heat exchangers for heating at least an inlet stream or cooling at least an outlet stream of the one or more reactors, and one or more adsorption towers for filtering or removing one or more trace materials from the outlet stream of the one or more reactors. In some embodiments, the one or more adsorption towers comprise one or more adsorbents that are cartridge-type. In some embodiments, the one or more reactors comprise a start-up reactor and a main reactor. The start-up reactor can be configured to decompose ammonia into hydrogen and provide at least said hydrogen to the main reactor as fuel for combustion heating. In some embodiments, the start-up reactor is configured to heat the one or more catalysts using electrical heating, resistive heating, inductive heating, or Joule heating. In some embodiments, the start-up reactor is in fluid and/or thermal communication with the main reactor. In some embodiments, the one or more adsorption towers comprise two or more adsorption beds for on-demand adsorbent regeneration and continuous operation of the system.

In some embodiments, the system may further comprise one or more valves or flow control units for selectively redirecting the reactor outlet stream between the first and second adsorption beds. In some embodiments, the system may further comprise a controller configured to control the one or more valves or flow control units to redirect the reactor outlet stream to the regenerated adsorption bed. In some embodiments, the system may further comprise one or more separate heat exchangers for regenerating the adsorption tower or towers. In some embodiments, the system may further comprise a pump or blower configured to remove trace ammonia from the reactor outlet stream (e.g., during adsorbent regeneration) and combine the trace ammonia stream with an outlet stream from a fuel cell in fluid communication with the one or more reactors and/or the one or more adsorption towers' fired heaters. In some embodiments, the system may further comprise one or more fuel cells in fluid communication with the one or more reactors. In some embodiments, the system may further comprise one or more ammonia tanks in fluid communication with the one or more reactors. In some embodiments, the one or more heat exchangers for the reactor outlet stream and/or inlet stream can be in thermal communication with an ammonia storage tank to provide heating energy for ammonia evaporation within the ammonia storage tank. In some embodiments, the reactor outlet and/or inlet streams may be in thermal communication with a stream from an ammonia storage tank to evaporate the ammonia and/or increase the temperature. In some embodiments, the system may further comprise an ammonia storage tank in thermal communication with the one or more fuel cells to recover waste heat from the one or more fuel cells to provide heating energy for ammonia evaporation in the ammonia storage tank. In some embodiments, the system may comprise one or more heat exchangers in thermal communication with the one or more fuel cells to recover waste heat from the one or more fuel cells to provide heating energy for ammonia evaporation in the one or more heat exchangers. In some embodiments, the reactor inlet or outlet stream comprises at least one of hydrogen, nitrogen, and ammonia. In some embodiments, the one or more trace materials comprise ammonia. In some embodiments, the ammonia comprises unconverted ammonia. In some embodiments, the system may further comprise one or more additional heat exchangers in thermal communication with the ammonia storage tank to provide heating energy for ammonia evaporation inside the ammonia storage tank.

In some embodiments, the one or more reactors may be configured to be mounted on a vehicle. In some embodiments, the vehicle comprises a land vehicle, an air vehicle, or an underwater vehicle (e.g., a boat, a ship, or any other type of marine vehicle). In some embodiments, the one or more reactors are configured to be mounted on a front region, a rear region, a side region, an inner region, an outer region, a top region, or a bottom region of the vehicle. In some embodiments, the one or more reactors, the one or more heat exchangers, and the one or more adsorption towers are configured to be mounted on different portions or regions of the vehicle. In some embodiments, the vehicle includes a drone, a car, or a truck. In some embodiments, the vehicle is configured to be operated by a human or a computer. In some embodiments, the vehicle is autonomous or semi-autonomous.

In another aspect, the disclosure provides a system, the system comprising: (a) an ammonia storage tank; (b) a reactor in fluid communication with the ammonia storage tank, the reactor configured to decompose ammonia received from the ammonia storage tank to produce a reactor outlet stream comprising hydrogen; (c) one or more adsorber configured to filter or remove unconverted ammonia from at least a portion of the reactor outlet stream to provide a filtered reactor outlet stream; and (d) one or more fuel cells in fluid communication with at least one of the reactor and the one or more adsorber, the one or more fuel cells (i) receiving the filtered reactor outlet stream from the one or more adsorber and (ii) processing the filtered reactor outlet stream to generate electricity. and (iii) one or more fuel cells configured to discharge a fuel cell outlet stream comprising unconverted hydrogen; and (e) one or more combustors at least partially embedded within the reactor, the one or more combustors being in fluid communication with at least one of (i) the ammonia storage tank, the reactor, the one or more adsorber, and the one or more fuel cells, and (ii) configured to combust at least a portion of the ammonia stream from the ammonia tank, the reactor outlet stream, the filtered reactor outlet stream, or the fuel cell outlet stream to generate thermal energy for heating the reactor in a plurality of different regions to promote ammonia decomposition.

In some embodiments, the one or more combustors are configured to combust at least a portion of the reactor outlet stream to heat different regions within the reactor. In some embodiments, the reactor outlet stream further comprises undecomposed ammonia. In some embodiments, the reactor outlet stream further comprises nitrogen.

In some embodiments, the one or more combustors are configured to combust at least a portion of the fuel cell outlet stream to heat different regions within the reactor. In some embodiments, the fuel cell outlet stream further comprises hydrogen. In some embodiments, the fuel cell outlet stream further comprises nitrogen.

In some embodiments, the one or more combustors include one or more different combustion heating zones configured to heat different regions within the reactor. In some embodiments, the one or more combustors include one or more air-fuel contact zones configured to mix the hydrogen-containing stream with the oxygen-containing stream to promote combustion.

In some embodiments, the combustor or combustors are cylindrical or circular in cross-section. In some embodiments, the combustor or combustors are concentric with the reactor.

In some embodiments, the system further comprises an air supply unit in fluid communication with the one or more combustors, the air supply unit configured to supply at least oxygen to the one or more combustors. In some embodiments, the air supply unit comprises a fan, a blower, a compressor, a compression cylinder, a venturi restrictor, a turbine, or a turbocharging unit. In some embodiments, the air supply unit comprises a turbocharging unit driven by a combustor exit flow from the one or more combustors.

In some embodiments, the system comprises a mobile system having a volume of up to about 2 ^m3 .

In some embodiments, the combustor or combustors are rectangular in shape or cross-section.

In some embodiments, the one or more combustors comprise a high temperature refractory material configured to improve the stability of the combustor. In some embodiments, the high temperature refractory material comprises alumina, magnesia, silica, lime, steel, tungsten, molybdenum, tungsten carbide, or any combination thereof. In some embodiments, the high temperature refractory material comprises a metal oxide selected from the group consisting of _Al2O3 , _SiO2 , _ZrO2 , _VO2 , Ta, Ni alloys, Al alloys, Mo alloys, Cr alloys, Si alloys, or any combination thereof. In some embodiments, the refractory material is coated on one or more surfaces of the one or more combustors.

In some embodiments, the filtered reactor outlet stream contains up to about 100 ppm ammonia. In some embodiments, the filtered reactor outlet stream contains up to about 10 ppm ammonia.

In some embodiments, the one or more combustors comprise an atmospheric combustor, a naturally aspirated combustor, a swirl combustor, or a pressurized combustor. In some embodiments, the atmospheric combustor is configured to receive a supply of air or oxygen from a compression cylinder or an air intake unit (e.g., a fan, blower, compressor, etc.). In some embodiments, the naturally aspirated combustor may be configured to receive a supply of air or oxygen from the surrounding environment based in part on a vacuum induced within the combustor. In some embodiments, the pressurized combustor is configured to receive a supply of air or oxygen from an air intake unit (e.g., a fan, blower, compressor, etc.) that couples to a turbine, the turbine being driven by one or more exhaust gases from the pressurized combustor.

In some embodiments, the one or more combustors are configured to combust an air-fuel mixture that is at least partially premixed upstream of the combustion zone. In some embodiments, the one or more combustors are configured to combust an air-fuel mixture, where the air and fuel are mixed at or near the combustion zone to generate a flame. In some embodiments, the one or more combustors are configured to combust an air-fuel mixture, where the air and fuel are mixed in a series of premix zones upstream of the combustion zone to improve heat distribution. In some embodiments, each premix zone in the series of premix zones is configured to pre-combust at least a portion of the air-fuel mixture, thereby distributing heat more uniformly throughout the combustor and reducing one or more localized hot spot temperatures. In some embodiments, the series of premix zones comprises at least one premix zone. In some embodiments, the series of premix zones comprises at least two premix zones. In some embodiments, the series of premix zones comprises at least three premix zones.

In some embodiments, the combustion fuel includes at least one of a reactor outlet stream, a stream from an ammonia storage tank, a filtered reactor outlet stream, or a fuel cell outlet stream.

In some embodiments, one or more combustors are configured to combust at least a portion of the ammonia stream from the ammonia storage tank to generate thermal energy for heating the reactor in multiple different regions to facilitate ammonia decomposition.

In another aspect, the present disclosure provides a system, the system comprising one or more reactors configured to crack ammonia provided to the one or more reactors to produce hydrogen, nitrogen, and/or ammonia, and one or more fuel cells in fluid communication with the one or more reactors, the one or more fuel cells configured to receive and process hydrogen to produce electrical energy, the one or more reactors and the one or more fuel cells configured to be mounted to an aviation vehicle, the one or more fuel cells in electrical communication with one or more motors or drive devices of the aviation vehicle to drive the one or more motors or drive devices of the aviation vehicle.

In some embodiments, the one or more reactors include a start-up reactor and a main reactor.

In some embodiments, the start-up reactor is configured to crack at least a portion of the ammonia supplied to the one or more reactors to produce hydrogen, nitrogen, and/or ammonia. In some embodiments, the start-up reactor is in fluid communication with the main reactor, and the main reactor is configured to combust at least a portion of the outlet stream from the start-up reactor to heat the main reactor.

In some embodiments, the outlet stream from the start-up reactor includes hydrogen and at least one of ammonia or nitrogen.

In some embodiments, the one or more reactors include two or more start-up reactors and two or more main reactors.

In some embodiments, the system further includes a controller configured to control the flow of ammonia supplied to the one or more reactors based on a desired power output from the one or more fuel cells.

In some embodiments, the system further comprises one or more adsorbents in fluid communication with the one or more reactors, the one or more adsorbents configured to process an outlet stream from the one or more reactors to filter or remove ammonia from the outlet stream, the outlet stream comprising at least hydrogen and/or nitrogen.

In some embodiments, the adsorber is in fluid communication with one or more fuel cells, and the adsorber is configured to direct hydrogen and/or nitrogen to the one or more fuel cells after filtering or removing ammonia from the outlet stream of the one or more reactors.

In some embodiments, the system further comprises one or more combustors in fluid communication with the one or more fuel cells, the one or more combustors configured to combust an outlet stream from the one or more fuel cells to heat the one or more reactors.

In some embodiments, the outlet stream from one or more fuel cells includes unconverted hydrogen.

In some embodiments, the one or more fuel cells are in communication with an electrical load.

In some embodiments, the electrical load includes one or more motors or drives of the air vehicle.

In some embodiments, the one or more combustors are disposed at least partially within the one or more reactors.

In some embodiments, the system further comprises an auxiliary battery for powering one or more motors or drives of the air vehicle.

In some embodiments, the system further comprises one or more heat exchangers for cooling the outlet stream of the one or more reactors. In some embodiments, the system further comprises one or more heat exchangers for vaporizing and/or heating a stream from the one or more fuel storage tanks.

In some embodiments, the system further comprises one or more fuel storage tanks mounted on the aircraft vehicle, the fuel storage tanks in fluid communication with the one or more heat exchangers and/or the one or more reactors to supply ammonia.

In some embodiments, the one or more fuel cells are in thermal communication with one or more fuel storage tanks and/or one or more heat exchangers to facilitate the transfer of thermal energy from the one or more fuel cells to the one or more fuel storage tanks and/or one or more heat exchangers to heat the one or more fuel storage tanks and/or one or more heat exchangers for ammonia evaporation.

In some embodiments, one or more heat exchangers are in thermal communication with the outlet stream from the one or more fuel cells to cool the heat exchanger and/or the outlet stream from the one or more reactors, and the outlet stream from the one or more fuel cells includes at least air or oxygen.

In some embodiments, the system further comprises a controller operatively coupled to the one or more valves to control (i) the flow of ammonia to the one or more reactors or the one or more heat exchangers, or (ii) the flow of hydrogen to the one or more fuel cells. In some embodiments, the controller is configured to provide dynamic power control by controlling the operation of the one or more valves.

In some embodiments, each of the one or more reactors is configured to crack at least about 30 liters/min of ammonia.

In some embodiments, the system further comprises a controller and one or more sensors operably coupled to the controller, the controller configured to monitor the temperature of the one or more reactors, the ammonia and/or hydrogen flow pressure, and/or the electrical output of the one or more fuel cells based on one or more measurements obtained using the one or more sensors. In some embodiments, the controller is configured to increase the power of the air supply unit to increase the air flow rate to the one or more combustors of the one or more reactors if the temperature of the one or more reactors drops or falls below a threshold temperature. In some embodiments, the controller is configured to adjust one or more valves coupled to the ammonia storage tank to maintain or reach a threshold pressure point corresponding to a desired ammonia flow rate and electrical output.

In some aspects, the present disclosure provides a system for processing ammonia, the system comprising one or more reactors for decomposing ammonia, one or more heating elements embedded in at least one of the one or more reactors, and one or more flow paths disposed around or near the one or more heating elements to improve flow fields and uniformity of heating, the one or more heating elements configured to heat a fluid, including one or more reformed gases, as the fluid flows along the one or more flow paths disposed around or near the one or more heating elements.

In some embodiments, each of the one or more reactors is configured to output a volume or amount of hydrogen usable to generate at least about 25 kilowatts of power.

In some embodiments, the reactor(s) (i) comprise one or more flow paths and (ii) comprise one or more enclosed or partially enclosed regions surrounding the one or more heating elements, the one or more enclosed or partially enclosed regions allowing the one or more reformed gases to pass around the one or more heating elements and facilitating heat transfer between the one or more heating elements and the one or more reformed gases.

In some embodiments, the one or more heating elements comprise a combustion heater, an electric heater, or a hybrid heating unit comprising both a combustion heater and an electric heater.

In some embodiments, the hybrid heating unit includes a fired heater and an electric heater in series along the length of at least one reactor.

In some embodiments, the hybrid heating unit includes parallel fired heaters and electric heaters perpendicular to the length of at least one reactor.

In some embodiments, the system further comprises one or more catalysts configured to decompose or crack ammonia when heated by the one or more heating elements.

In some embodiments, the catalyst(s) are provided externally or externally to the heating element(s).

In some embodiments, the one or more heating elements have one or more exterior surfaces in thermal communication with fluid flowing along or through the one or more flow paths, and the one or more catalysts are disposed adjacent to and/or in thermal communication with the outer surfaces of the one or more heating elements.

In some embodiments, one or more catalysts are disposed or provided within one or more flow paths.

In some embodiments, one or more of the flow channels are of circular cross-section to allow for uniform heating of the fluid.

In some embodiments, the one or more gas inlets are configured to distribute the fluid flow into multiple flow paths within at least one of the one or more reactors.

In some embodiments, the one or more heating elements are configured to provide multiple heating zones within the reactor, the multiple heating zones having different, pre-determined or adjustable temperatures and/or heating powers.

In some embodiments, one or more reactors have a cross-sectional shape including a circle, an ellipse, an oval, or any polygon with three or more sides.

In some embodiments, one or more of the channels have a cross-sectional shape including a circle, an ellipse, an oval, or any polygon with three or more sides.

In some embodiments, one or more reactors have a cross-sectional shape similar to the cross-sectional shape of the flow passages in one or more flow passages.

In some embodiments, one or more reactors have a cross-sectional shape that is different from the cross-sectional shape of the flow passages in one or more flow passages.

In some embodiments, the one or more reactors include (i) a first flow path for passing reformate gas from one or more gas inlets along a portion of one or more heating elements, and (ii) a second flow path for directing the reformate gas to one or more gas outlets.

In some embodiments, the first flow path and the second flow path are oriented in different directions.

In some embodiments, the first flow path and the second flow path are positioned adjacent to one another to allow transfer of thermal energy between (i) one or more reformate gases entering the one or more reactors via one or more gas inlets and (ii) one or more reformate gases exiting the one or more reactors via one or more gas outlets.

In some embodiments, the system further comprises a plurality of flow paths, a first of the plurality of flow paths being associated with the first flow path and a second of the one or more flow paths being associated with the second flow path, or both the first and second flow paths having one or more internal extended heat transfer surfaces configured to enhance heat transfer.

In some embodiments, each individual heating element of one or more heating elements includes one or more dedicated flow paths.

In some embodiments, one or more heating elements each have a different respective flow path.

In some embodiments, the heating element or elements are configured to (i) control the temperature and/or heating power of different regions of the heating element or elements or the reactor or reactors, or (ii) adjust the position of one or more heating zones within the reactor or reactors to optimize ammonia thermal reforming efficiency and/or conversion efficiency. The fuel reforming or conversion capacity of the reactors may be determined or calculated based on measurements taken downstream of the reactor or reactors.

In some embodiments, the system further comprises a plurality of different catalysts for decomposing ammonia, the plurality of different catalysts being in thermal communication with at least one of the one or more heating elements.

In some embodiments, the plurality of different catalysts includes a first catalyst having a first set of ammonia reforming properties and a second catalyst having a second set of ammonia reforming properties.

In some embodiments, the first catalyst and the second catalyst are in thermal communication with different heating elements, different locations or regions of the same heating element, or different heating zones generated by one or more heating elements.

In some embodiments, one or more flow paths include one or more baffles to induce turbulence, mixing, increase flow residence time, and/or improve flow uniformity and heat transfer.

In some embodiments, the system further comprises a controller configured to control the flow of ammonia into one or more flow paths by adjusting one or more flow control units.

In some embodiments, the controller is configured to control the flow of ammonia based on the heating power input and/or temperature to each of the one or more heating elements.

In some embodiments, the system further comprises a controller configured to control the operation or temperature of one or more heating elements.

In some embodiments, the system further comprises one or more heat exchangers between one or more hot outlet streams and one or more cold inlet streams of one or more reactors.

In some embodiments, each of the one or more reactors is configured to reform at least about 300 L/min of ammonia. In some embodiments, each of the one or more reactors is configured to reform at least about 300 standard liters per minute (SLM) of ammonia.

In some embodiments, the system further comprises one or more fuel cells in fluid communication with the one or more reactors, the one or more fuel cells configured to receive and process hydrogen produced by the decomposition of ammonia to produce electrical energy, and the system has an energy density of at least about 600 Wh/kg, at least about 400 Wh/L, or both.

In some embodiments, the system further comprises a plurality of reactors, a first reactor in the plurality of reactors comprising an electric heater and a second reactor in the plurality of reactors comprising a fired heater, the first reactor and the second reactor being in fluid communication in series or parallel.

In another aspect, the disclosure provides a system, the system comprising: one or more reactors in fluid communication with one or more ammonia sources, the one or more reactors comprising one or more catalysts; and a plurality of heating elements in thermal communication with the one or more catalysts, the one or more reactors configured to make or produce hydrogen from ammonia provided by or received from the one or more ammonia sources using the one or more catalysts and the plurality of heating elements, the plurality of heating elements comprising at least one electric heater and at least one fired heater.

In some embodiments, the one or more reactors include a first reactor and a second reactor in fluid communication with the first reactor.

In some embodiments, the first reactor comprises (i) a first catalyst and (ii) a start-up heating unit configured to heat the first catalyst, such that the first catalyst is configured to produce or extract hydrogen from ammonia.

In some embodiments, the power source heating unit includes at least one electric heater.

In some embodiments, at least one electric heater includes one or more electrodes for passing an electric current through the first catalyst to heat the first catalyst.

In some embodiments, the second reactor comprises (i) a second catalyst, and (ii) one or more main heating units configured to heat the second catalyst, such that the second catalyst is configured to produce or extract hydrogen from ammonia.

In some embodiments, one or more of the main heating units includes at least one fired heater.

In some embodiments, at least one fired heater is configured to heat at least a portion of the second catalyst by combusting hydrogen produced by the first reactor.

In some embodiments, the system further comprises one or more ammonia sources.

In some embodiments, the one or more ammonia sources include one or more liquid fuel storage tanks, and the ammonia is stored as liquid ammonia in the one or more liquid fuel storage tanks.

In some embodiments, the liquid ammonia is stored at a temperature in the range of about 15 to about 30° C. and at a pressure in the range of 7 to 12 bar absolute.

In some embodiments, the liquid ammonia is stored at a gauge pressure ranging from about atmospheric pressure to about 20 bar.

In some embodiments, the liquid ammonia is stored at a temperature ranging from about -40 to about 20°C and at an absolute pressure ranging from about 0.5 bar to about 9 bar.

In some embodiments, the system further comprises one or more fuel cells in fluid communication with the one or more reactors.

In some embodiments, the system further comprises one or more adsorbents in fluid communication with the one or more reactors and the one or more fuel cells, the one or more adsorbents configured to filter or remove unconverted ammonia from the outlet stream from the one or more reactors.

In some embodiments, the one or more adsorbents are configured to provide the filtered reactor outlet stream to one or more fuel cells.

In some embodiments, the one or more fuel cells are configured to (i) receive a filtered reactor outlet stream from the one or more adsorber, (ii) process the filtered reactor outlet stream to generate electricity, and (iii) discharge a fuel cell outlet stream that includes unconverted hydrogen.

In some embodiments, one or more of the multiple heating elements are in fluid and/or thermal communication with the fuel cell outlet stream.

In some embodiments, the one or more heating elements are configured to combust unconverted hydrogen to heat the one or more catalysts.

In some embodiments, the one or more reactors include one or more flow paths for ammonia, the one or more flow paths (i) surrounding at least one heating element of the plurality of heating elements, and (ii) allowing flow of ammonia around the at least one heating element to facilitate heat transfer between the heating element and the ammonia.

In some embodiments, the reactor or reactors include one or more flow paths adjacent to the heating elements, the flow paths allowing flow of ammonia adjacent to or along the heating element or elements to facilitate heat transfer between the heating element or elements and the ammonia.

In some embodiments, each of the one or more flow channels is concentric or coaxial with a respective one of the one or more heating elements relative to the longitudinal axis.

In some embodiments, multiple heating elements are in fluid and/or thermal communication with ammonia flowing along or through one or more flow paths.

In some embodiments, one or more flow channels are provided around or near the heating element to improve the flow field and uniformity of heating.

In some embodiments, the heating element is configured to heat the ammonia as it flows along or through one or more flow paths disposed around or near the heating element.

In some embodiments, at least one fired heater is configured to combust the outlet stream from the one or more reactors to generate thermal energy for heating the one or more reactors.

In some embodiments, at least one fired heater is configured to combust an outlet stream from one or more adsorbents in fluid communication with the one or more reactors to generate thermal energy for heating the one or more reactors.

In some embodiments, at least one fired heater is configured to combust an outlet stream from one or more fuel cells in fluid communication with the one or more reactors to generate thermal energy for heating the one or more reactors.

In some embodiments, at least one combustion heater includes a swirl combustor, a diffusion flame combustor, a micro-mixer combustor, or any combination thereof.

In some embodiments, the exhaust of at least one fired heater can be used to heat or preheat ammonia.

In some embodiments, at least one fired heater is configured to combust a mixture of air and a combustion fuel that includes hydrogen.

In some embodiments, at least one fired heater includes one or more zones for mixing or premixing air and combustion fuel upstream of a combustion region of the at least one fired heater.

In some embodiments, each of the one or more zones is configured to combust or pre-combust at least a portion of the mixture of air and combustible fuel to distribute heat evenly throughout the fired heater and reduce localized hot spot temperatures.

In some embodiments, the multiple heating elements include a hybrid heating unit that includes at least one electric heater and at least one combustion heater.

In some embodiments, the first reactor includes at least one electric heater and the second reactor includes at least one fired heater.

In some embodiments, the first reactor and the second reactor are in fluid communication in series such that the first outlet stream of the first reactor enters the second reactor.

In some embodiments, the first reactor and the second reactor are in parallel fluid communication such that the first outlet stream of the first reactor and the second outlet stream of the second reactor combine to produce a combined outlet stream.

In some embodiments, one or more catalysts are provided adjacent to and/or in thermal communication with one or more exterior surfaces of the heating element.

In some embodiments, one or more reactors have a cross-sectional shape selected from the group consisting of a circle, an ellipse, an oval, and any polygon having three or more sides.

In some embodiments, one or more reactors include one or more flow channels having a cross-sectional shape selected from the group consisting of a circle, an ellipse, an oval, and any polygon having three or more sides.

In some embodiments, each of the one or more reactors has a cross-sectional shape similar to the cross-sectional shape of the flow passage of each respective reactor of the one or more reactors.

In some embodiments, each of the one or more reactors has a cross-sectional shape that is different from the cross-sectional shape of the flow passage of each respective reactor of the one or more reactors.

In some embodiments, the one or more reactors include (i) a first flow path for a reformate gas that includes ammonia, and (ii) a second flow path for a reformate gas produced from processing the reformate gas.

In some embodiments, the first flow path allows flow of the reformed gas along at least a portion of the plurality of heating elements.

In some embodiments, the second flow path allows the flow of reformate gas to one or more outlets of the reactor.

In some embodiments, the first flow path and the second flow path are oriented in different directions.

In some embodiments, the first flow path and the second flow path are in fluid communication with each other to allow for heat transfer between the reformate gas and the reformate gas.

In some embodiments, the system further comprises one or more heat exchangers.

In some embodiments, the one or more heat exchangers are configured to exchange heat between the outlet stream of the one or more reactors and ammonia streams from one or more ammonia sources.

In some embodiments, the one or more heat exchangers are configured to facilitate the transfer of thermal energy between (i) a flow of ammonia from one or more ammonia sources and (ii) one or more fuel cells in fluid communication with the one or more reactors to vaporize the ammonia.

In some embodiments, the system further comprises one or more control units for regulating the temperature of the outlet stream of one or more reactors and/or the multiple heating elements.

In some embodiments, the one or more control units include a controller and one or more sensors operably coupled to the controller.

In some embodiments, the controller is configured to monitor and control (i) the temperature of one or more reactors, (ii) the ammonia and/or hydrogen flow pressure, and/or (iii) the electrical output of one or more fuel cells in fluid communication with one or more reactors based at least in part on one or more measurements obtained using one or more sensors.

In some embodiments, the controller is configured to decrease or increase the air flow rate, decrease or increase the combustion fuel flow rate, or decrease or increase both the air flow rate and the combustion fuel flow rate to at least one of the fired heaters based on the temperature of one or more reactors.

In some embodiments, the controller is configured to increase the airflow using a fan, blower, or compressor.

In some embodiments, the controller is configured to increase the combustion fuel flow rate by increasing the ammonia flow rate or decreasing the hydrogen consumption of the fuel cell.

In some embodiments, the controller is configured to decrease or increase the power output of one or more fuel cells based on the temperature of one or more reactors.

In some embodiments, the controller is configured to increase the flow rate of ammonia to one or more reactors based on the temperature of the one or more reactors or the power output of the one or more fuel cells.

In some embodiments, the controller is configured to increase the flow rate of ammonia using a valve and/or a pump.

In some embodiments, the system is configured to reform ammonia at a rate of at least about 50 L/min STP of ammonia gas.

In some embodiments, the controller is configured to increase or decrease the power provided to at least one electric heater based on the temperature of the one or more reactors.

In some embodiments, the system has an energy density of at least about 600 Wh/kg, or at least about 400 Wh/L.

In some embodiments, the system has an operating pressure of less than about 30 bar.

In some embodiments, the system further comprises a pressure swing adsorption (PSA) unit to remove nitrogen from the outlet stream of one or more reactors.

In some embodiments, the PSA is installed or positioned downstream of one or more adsorbents in fluid communication with one or more reactors.

In some embodiments, the PSA unit produces an exhaust stream comprising nitrogen and hydrogen, and the exhaust stream is fed to at least one fired heater.

In some embodiments, the filtered reactor outlet stream contains less than 100 ppm ammonia.

In some embodiments, the one or more adsorbents are configured to be regenerated by exchanging heat with one or more electric heaters embedded in the one or more adsorbents, exhaust from at least one fired heater, and/or an outlet stream from one or more reactors.

In some embodiments, one or more adsorbents can be replaced with one or more new or regenerated adsorbents.

In some embodiments, the one or more catalysts include a support and at least one metal selected from ruthenium, nickel, rhodium, iridium, cobalt, iron, platinum, chromium, palladium, molybdenum, tantalum, or copper.

In some embodiments, the catalyst or catalysts are promoted with at least one metal selected from Li, Na, K, Rb, Cs, Mg, Ca, Ba, Sr, La, Ce, Pr, Sm, or Gd.

In some embodiments, the support comprises at least one material selected from Al2O3, MgO, CeO2, ZrO2, La2O3, SiO2, Y2O3, TiO2, SiC, hexagonal BN (boron nitride), BN nanotubes, silicon carbide, one or more zeolites, LaAlO3, CeAlO3, MgAl2O4, CaAl2O4, or one or more carbon nanotubes.

In some embodiments, the first reactor is configured to initiate an ammonia reforming process.

In some embodiments, the reforming process is initiated using at least one electric heater or an electric current passing through one or more catalysts.

In some embodiments, at least one electric heater or electrical current is turned off after the reforming process has begun.

In some embodiments, the fuel cell or fuel cells consume less than 90% of the hydrogen from the reactor or reactors and output one or more outlet streams containing the remaining unconverted hydrogen.

In some embodiments, the operating temperature of one or more reactors is less than 900°C.

In some embodiments, the system further comprises one or more pumps for supplying ammonia and increasing the flow pressure of the ammonia.

In some embodiments, the system does not emit carbon.

In some embodiments, the fuel reforming or conversion rate of one or more reactors is greater than about 90%.

In some embodiments, the fuel heating value to useful electrical energy output efficiency of the system is at least about 25% and at most about 50%.

In some embodiments, the system further includes one or more batteries, one or more DC/DC converters, and one or more motors for powering the mobile vehicle.

In some embodiments, one or more batteries provide power to power the system.

In some embodiments, the one or more batteries are configured to provide power to power the system by providing power to at least one electric heater.

In some embodiments, the system further comprises one or more fuel cells for generating electrical power, the electrical power generated using the one or more fuel cells charging the one or more batteries after the start-up process is initiated or terminated.

In some embodiments, the fuel cell or fuel cells provide a substantially stable power or load to a moving vehicle, and the battery or batteries enable dynamic load following capabilities.

In some embodiments, the mobile vehicle includes an aerial vehicle, an unmanned aerial vehicle, a marine or underwater vehicle, or a terrestrial vehicle.

In some embodiments, the system further comprises one or more fuel cells for generating electrical power, the electrical power generated using the one or more fuel cells being supplied to a fixed or non-moving platform or network.

In some embodiments, the fixed or non-mobile platform or network comprises a power grid.

In some embodiments, multiple heating elements are at least partially embedded within one or more reactors.

In another aspect, the present disclosure provides a system, the system comprising one or more reactors in fluid communication with one or more ammonia sources and at least one heating element at least partially disposed within the one or more reactors, the one or more reactors comprising a plurality of flow paths surrounding the at least one heating element to improve flow field and heating uniformity of ammonia received from or supplied by the one or more ammonia sources, the plurality of flow paths providing a flow path for ammonia adjacent to the at least one heating element to facilitate transfer of thermal energy between the at least one heating element and the ammonia.

In some embodiments, the at least one heating element comprises a first heating element for heating a first portion of the ammonia and a second heating element for heating a second portion of the ammonia, and the plurality of flow paths comprises (i) a first flow path for flowing the first portion of the ammonia through the one or more reactors, and (ii) a second flow path for flowing the second portion of the ammonia through the one or more reactors.

In some embodiments, the multiple flow paths include two or more flow paths that are fluidly separated from one another during heating of (i) a first portion of the ammonia using a first heating element and (ii) a second portion of the ammonia using a second heating element.

In some embodiments, the plurality of flow paths includes a first flow path that extends along or around a portion of the first heating element and a second flow path that extends along or around a portion of the second heating element.

In some embodiments, at least one heating element comprises an electric heater or a combustion heater.

In some embodiments, the first heating element and the second heating element comprise combustion heaters.

In some embodiments, the first heating element comprises a combustion heater and the second heating element comprises an electric heater.

In some embodiments, at least one heating element comprises multiple fired heaters configured to operate independently.

In some embodiments, at least one heating element comprises a hybrid heating unit comprising a combustion heater and an electric heater.

In some embodiments, the combustion heater and the electric heater are arranged in series.

In some embodiments, the combustion heater and the electric heater are arranged in parallel.

In some embodiments, the system further comprises one or more catalysts configured to decompose or crack the ammonia, and the at least one heating element is configured to heat the one or more catalysts to facilitate the decomposition or cracking of the ammonia.

In some embodiments, the catalyst or catalysts are provided externally or externally to at least one heating element.

In some embodiments, the at least one heating element has one or more outer surfaces, and the one or more catalysts are disposed adjacent to and/or in thermal communication with the outer surface of the at least one heating element.

In some embodiments, one or more catalysts are disposed or provided in multiple flow paths.

In some embodiments, at least one heating element is configured to provide multiple heating zones within one or more reactors, the multiple heating zones having different temperatures and/or heating profiles.

In some embodiments, the one or more reactors include (i) a first flow path for passing ammonia through the one or more reactors to heat the ammonia using at least one heating element, and (ii) a second flow path for directing reformate gas produced from the decomposition or cracking of ammonia to one or more outlets of the one or more reactors.

In some embodiments, the first flow path and the second flow path are oriented in different directions.

In some embodiments, the first flow path and the second flow path are positioned adjacent to one another to allow for the transfer of thermal energy between (i) ammonia entering the one or more reactors and (ii) reformate gas exiting the one or more reactors.

In some embodiments, the at least one heating element comprises a plurality of heating elements each having one or more dedicated flow paths for ammonia, and the plurality of flow paths comprises one or more dedicated flow paths.

In some embodiments, at least one heating element is configured to (i) control the temperature and/or heating profile of different regions of one or more reactors, or (ii) adjust the position of one or more heating zones within one or more reactors to optimize ammonia thermal reforming efficiency and/or conversion.

In some embodiments, the system further includes a plurality of different catalysts for decomposing ammonia, the plurality of different catalysts being in thermal communication with at least one heating element.

In some embodiments, the plurality of different catalysts includes a first catalyst having a first set of ammonia reforming properties and a second catalyst having a second set of ammonia reforming properties.

In some embodiments, the first catalyst and the second catalyst are in thermal communication with different heating elements.

In some embodiments, the first catalyst and the second catalyst are in thermal communication with different locations or regions of the same heating element.

In some embodiments, the first catalyst and the second catalyst are in thermal communication with different heating zones generated by at least one heating element.

In some embodiments, one or more flow paths include one or more baffles to induce turbulence or mixing, increase flow residence time, and/or improve flow uniformity and heat transfer.

In some embodiments, the system further comprises a controller configured to control the flow of ammonia into one or more flow paths by adjusting one or more flow control units.

In some embodiments, the controller is configured to control the flow of ammonia based on the amount of heating power input to the at least one heating element and/or the temperature of the at least one heating element.

In some embodiments, the system further comprises a controller configured to control the operation or temperature of the at least one heating element.

In some embodiments, the system further comprises one or more heat exchangers between the one or more hot outlet streams and the one or more cold inlet streams of the one or more reactors.

In some embodiments, each of the one or more reactors is configured to reform ammonia gas at a rate of at least about 50 L/min STP.

In some embodiments, the system further comprises one or more fuel cells in fluid communication with the one or more reactors, the one or more fuel cells configured to receive and process hydrogen produced from the decomposition of ammonia to produce electrical energy.

In some embodiments, the system has an energy density of at least about 600 Wh/kg, at least about 400 Wh/L, or both.

In some embodiments, the one or more reactors comprises a plurality of reactors, a first reactor of the plurality of reactors comprises an electric heater, a second reactor of the plurality of reactors comprises a fired heater, and the first reactor and the second reactor are in fluid communication with each other.

In some embodiments, the first reactor and the second reactor are arranged in parallel such that the first outlet stream of the first reactor and the second outlet stream of the second reactor combine to produce a mixed outlet stream.

In some embodiments, the first reactor and the second reactor are arranged in series and configured such that the first outlet stream of the first reactor enters the second reactor.

In some embodiments, the system further comprises one or more fuel cells in fluid communication with the one or more reactors.

In some embodiments, the system further comprises one or more adsorbents in fluid communication with the one or more reactors and the one or more fuel cells, the one or more adsorbents configured to filter or remove unconverted ammonia from the outlet stream from the one or more reactors.

In some embodiments, the one or more adsorbents are configured to provide the filtered reactor outlet stream to one or more fuel cells.

In some embodiments, the one or more fuel cells are configured to (i) receive the filtered reactor outlet stream from the one or more adsorber, (ii) process the filtered reactor outlet stream to generate electricity, and (iii) discharge a fuel cell outlet stream that includes unconverted hydrogen.

In some embodiments, at least one heating element is in fluid communication with the fuel cell outlet stream.

In some embodiments, at least one heating element is configured to combust unconverted hydrogen to heat one or more catalysts disposed within one or more reactors.

In some embodiments, the system further comprises a pressure swing adsorption (PSA) unit configured to remove nitrogen from the outlet stream of one or more reactors.

In some embodiments, the PSA is installed or positioned downstream of one or more adsorbents in fluid communication with one or more reactors.

In some embodiments, the PSA unit produces an exhaust stream comprising nitrogen and hydrogen, and the exhaust stream is fed to at least one heating element.

In some embodiments, the system further comprises one or more heat exchangers.

In some embodiments, one or more heat exchangers are configured to exchange thermal energy between the outlet stream of one or more reactors and ammonia streams from one or more ammonia sources.

In some embodiments, the one or more heat exchangers are configured to facilitate the transfer of thermal energy between (i) the outlet stream of the one or more reactors and (ii) the surrounding environment to cool the outlet stream of the one or more reactors.

In some embodiments, the one or more heat exchangers are configured to facilitate the transfer of thermal energy between (i) a flow of ammonia from one or more ammonia sources and (ii) one or more fuel cells in fluid communication with the one or more reactors to vaporize the ammonia.

In some embodiments, the one or more heat exchangers are configured to facilitate the transfer of thermal energy between (i) a flow of ammonia from one or more ammonia sources and (ii) the ambient environment to vaporize the ammonia.

In some embodiments, at least one heating element is configured to combust an outlet stream from one or more reactors to generate thermal energy for heating the one or more reactors.

In some embodiments, at least one heating element is configured to combust an outlet stream from one or more adsorbents in fluid communication with the one or more reactors to generate thermal energy for heating the one or more reactors.

In some embodiments, at least one heating element is configured to combust an outlet stream from one or more fuel cells in fluid communication with the one or more reactors to generate thermal energy for heating the one or more reactors.

In some embodiments, at least one heating element is disposed within one or more catalysts.

In another aspect, the present disclosure provides a system, the system comprising one or more reactors configured to at least partially decompose ammonia provided to the one or more reactors to produce hydrogen, nitrogen, and/or ammonia; and one or more fuel cells in fluid communication with the one or more reactors, the one or more fuel cells configured to receive and process hydrogen and generate electrical energy, the one or more reactors and the one or more fuel cells configured to be mounted to an aviation vehicle, the one or more fuel cells in electrical communication with one or more motors or drive devices of the aviation vehicle to drive the one or more motors or drive devices of the aviation vehicle.

In some embodiments, the one or more reactors and the one or more fuel cells are configured to operate as an ammonia power pack unit.

In some embodiments, the ammonia power pack unit has a weight of less than about 100 kilograms.

In some embodiments, the ammonia power pack unit has a volume of less than about 200 liters.

In some embodiments, the ammonia power pack unit has an energy density of at least about 600 watt-hours/kilogram or at least about 400 watt-hours/liter.

In some embodiments, the one or more reactors include a first reactor and a second reactor in fluid communication with the first reactor.

In some embodiments, the first reactor is configured to decompose at least a portion of the ammonia supplied to the one or more reactors to produce hydrogen, nitrogen, and/or ammonia.

In some embodiments, the second reactor is configured to combust at least a portion of the outlet stream from the first reactor to heat or preheat the second reactor, the outlet stream from the first reactor comprising hydrogen and at least one of ammonia or nitrogen.

In some embodiments, the system further comprises one or more heating elements configured to provide thermal energy to at least partially decompose the ammonia.

In some embodiments, the system further comprises one or more catalysts in thermal communication with the one or more heating elements, the one or more catalysts configured to promote decomposition of the ammonia.

In some embodiments, the one or more heating elements comprise one or more electric heaters and/or combustors.

In some embodiments, the one or more heating elements include a combustor in fluid communication with the one or more fuel cells, the combustor configured to combust an outlet stream from the one or more fuel cells to heat the one or more reactors, the outlet stream including unconverted hydrogen.

In some embodiments, the system further includes a controller configured to control the flow of ammonia supplied to the one or more reactors based on a desired power output from the one or more fuel cells.

In some embodiments, the system further comprises one or more adsorbents in fluid communication with the one or more reactors, the one or more adsorbents configured to process an outlet stream from the one or more reactors to filter or remove ammonia from the outlet stream, the outlet stream comprising at least hydrogen and/or nitrogen.

In some embodiments, the adsorber is in fluid communication with one or more fuel cells, and the adsorber is configured to direct hydrogen and/or nitrogen to the one or more fuel cells after filtering or removing ammonia from the outlet stream of the one or more reactors.

In some embodiments, the one or more fuel cells are in communication with an electrical load and/or one or more batteries.

In some embodiments, one or more fuel cells are configured to power one or more batteries in communication with an electrical load.

In some embodiments, the electrical load includes one or more motors or drives of the air vehicle.

In some embodiments, the system further comprises one or more batteries for starting up the reactor(s), electrically preheating the reactor(s), and/or performing subsequent dynamic load following.

In some embodiments, activation occurs within about 30 minutes.

In some embodiments, the system further comprises an auxiliary battery for powering one or more motors or drives of the air vehicle.

In some embodiments, the system further comprises one or more fuel cells capable of charging the auxiliary battery during operation.

In some embodiments, the system further comprises one or more heat exchangers for (i) cooling the outlet stream of the one or more reactors, and/or (ii) vaporizing or heating the flow of ammonia from the one or more fuel storage tanks to the one or more reactors.

In some embodiments, the system further comprises one or more fuel storage tanks for storing and supplying ammonia to the one or more reactors, the one or more fuel storage tanks being mounted on the aircraft vehicle.

In some embodiments, the one or more fuel cells are in thermal communication with one or more fuel storage tanks to facilitate the transfer of thermal energy from the fuel cells to the fuel storage tanks to heat and/or vaporize the ammonia.

In some embodiments, the one or more fuel cells are in thermal communication with one or more heat exchangers to facilitate the transfer of thermal energy from the fuel cells to the one or more heat exchangers to heat and/or vaporize the ammonia.

In some embodiments, one or more heat exchangers are in thermal communication with the outlet stream from the one or more fuel cells to cool the heat exchanger and/or the outlet stream from the one or more reactors.

In some embodiments, the one or more heat exchangers are in thermal communication with the surrounding environment to cool the one or more heat exchangers.

In some embodiments, the system further comprises a controller configured to regulate (i) the flow of ammonia to the one or more reactors, or (ii) the flow of hydrogen to the one or more fuel cells.

In some embodiments, the controller is configured to perform dynamic power control by adjusting the flow of ammonia or hydrogen.

In some embodiments, each of the one or more reactors is configured to decompose at least about 30 liters/min STP ammonia gas.

In some embodiments, the system further comprises one or more sensors operably coupled to the controller, and the controller is configured to monitor the temperature of the one or more reactors, the ammonia flow pressure or flow rate, the hydrogen flow pressure or flow rate, and/or the electrical output of the one or more fuel cells based on one or more measurements obtained using the one or more sensors.

In some embodiments, the controller is configured to increase power to the air supply unit to increase air flow to one or more combustors of one or more reactors based on the temperature of the one or more reactors.

In some embodiments, the controller is configured to adjust the ammonia flow pressure to increase the ammonia flow rate and provide additional hydrogen to one or more combustors of one or more reactors based on the temperature of the one or more reactors.

In some embodiments, the controller is configured to increase the ammonia flow pressure to increase the ammonia flow rate and provide additional hydrogen to one or more combustors of one or more reactors based on the temperature of the one or more reactors.

In some embodiments, the controller is configured to adjust one or more valves in fluid communication with one or more fuel storage tanks containing ammonia to maintain or reach a threshold pressure point corresponding to a desired ammonia flow rate and power output.

In another aspect, the disclosure provides a method, the method including: (a) processing ammonia to make or produce hydrogen using one or more reactors, the one or more reactors comprising (i) one or more catalysts and (ii) a plurality of heating elements in thermal communication with the one or more catalysts, the plurality of heating elements comprising at least one electric heater and at least one combustion heater; and (b) supplying hydrogen to one or more fuel cells to produce electrical energy.

In some embodiments, the one or more reactors include a first reactor and a second reactor in fluid communication with the first reactor.

In some embodiments, the first reactor comprises (i) a first catalyst of the one or more catalysts, and (ii) a start-up heating and reforming unit configured to heat the first catalyst, the first catalyst configured to produce or extract hydrogen from ammonia.

In some embodiments, the start-up heating and reforming unit includes at least one electric heater.

In some embodiments, at least one electric heater includes one or more electrodes for passing an electric current through the first catalyst to heat the first catalyst.

In some embodiments, the second reactor comprises (i) a second catalyst of the one or more catalysts and (ii) one or more main heating units configured to heat the second catalyst, the second catalyst configured to produce or extract hydrogen from ammonia.

In some embodiments, one or more of the main heating units includes at least one fired heater.

In some embodiments, at least one fired heater is configured to heat at least a portion of the second catalyst by combusting at least a portion of the hydrogen produced using the first reactor.

In some embodiments, the method further includes, subsequent to (b), supplying electrical energy to an electrical load and/or one or more batteries.

In some embodiments, the method further comprises filtering or removing unconverted ammonia from the outlet stream from the one or more reactors prior to (b).

In some embodiments, unconverted ammonia is filtered or removed from the outlet stream using one or more adsorbents to produce a filtered reactor outlet stream.

In some embodiments, the one or more fuel cells are configured to (i) receive a filtered reactor outlet stream from the one or more adsorber, (ii) process the filtered reactor outlet stream to generate electrical energy, and (iii) discharge a fuel cell outlet stream that includes unconverted hydrogen.

In some embodiments, the method further includes combusting unconverted hydrogen from the one or more fuel cells to heat the one or more catalysts.

In some embodiments, the unconverted hydrogen is combusted using one or more of a number of heating elements.

In some embodiments, the method further includes combusting the outlet stream from the one or more reactors to generate thermal energy for heating the one or more reactors or the one or more catalysts.

In some embodiments, the method further includes combusting an outlet stream from one or more adsorbents in fluid communication with the one or more reactors to generate thermal energy for heating the one or more reactors or the one or more catalysts.

In some embodiments, the method further includes using a heat exchanger to facilitate the transfer of thermal energy between (i) the outlet stream of the one or more reactors and (ii) the stream of ammonia from the one or more ammonia sources.

In some embodiments, the method further includes using a heat exchanger to facilitate the transfer of thermal energy between (i) a flow of ammonia from the one or more ammonia sources and (ii) an outlet flow from the one or more fuel cells to vaporize the ammonia.

In some embodiments, the method further includes regulating the temperature of the outlet stream of one or more reactors and/or the plurality of heating elements using the controller.

In some embodiments, the method further includes using a controller to monitor and control (i) the temperature of the one or more reactors, (ii) the ammonia and/or hydrogen flow pressure, and/or (iii) the electrical output of the one or more fuel cells.

In some embodiments, the method further includes using the controller to adjust an air flow rate to the at least one fired heater, a combustion fuel flow rate to the at least one fired heater, or both an air flow rate and a combustion fuel flow rate to the at least one fired heater based on the temperature of the one or more reactors.

In some embodiments, the method further includes using the controller to adjust the power output or hydrogen consumption of the one or more fuel cells based on the temperature of the one or more reactors.

In some embodiments, the method further includes adjusting, using the controller, the flow rate of ammonia to the one or more reactors based on the temperature of the one or more reactors and/or the fuel cell power output.

In some embodiments, the method further comprises a pressure swing adsorption (PSA) unit to remove nitrogen from the outlet stream of one or more reactors.

In some embodiments, the PSA is installed or positioned downstream of one or more adsorbents in fluid communication with one or more reactors.

In some embodiments, the PSA unit produces an exhaust stream comprising nitrogen and hydrogen, and the exhaust stream is fed to at least one fired heater.

In some embodiments, the method further includes initiating an ammonia reforming process using the first reactor.

In some embodiments, initiating the reforming process includes providing an electric current through at least a portion of the one or more catalysts or at least a portion of the one or more electric heaters to heat the one or more catalysts and promote decomposition or cracking of ammonia.

In another aspect, the present disclosure provides a system, the system comprising an ammonia treatment apparatus comprising a plurality of reactors, the plurality of reactors comprising one or more electric reactors, the one or more electric reactors configured to (i) process ammonia to produce hydrogen, and (ii) provide at least a portion of the hydrogen to one or more combustion reactors and/or one or more fuel cells in fluid communication with the one or more electric reactors and/or the one or more combustion reactors.

In some embodiments, the system further comprises one or more combustion reactors.

In some embodiments, the one or more combustion reactors are configured to combust hydrogen to heat the one or more combustion reactors to a predetermined threshold temperature.

In some embodiments, the one or more combustion reactors are configured to (i) process ammonia to produce one or more combustion reactor outlet streams, and (ii) provide the one or more combustion reactor outlet streams to one or more fuel cells.

In some embodiments, the one or more combustion reactors include one or more swirl burners configured to mix or swirl (i) a first stream comprising a combustion fuel with (ii) a second stream comprising air to heat the one or more combustion reactors, and optionally the combustion fuel comprises hydrogen.

In some embodiments, the one or more swirl burners include one or more flow paths for directing the first and second flows along one or more helical or spiral flow paths to enhance combustion of the fuel.

In some embodiments, one or more electric reactors are heated or preheated using a power source.

In some embodiments, the system further comprises a heat exchanger configured to facilitate the transfer of thermal energy between (i) an inlet stream of ammonia to the ammonia treatment unit and (ii) one or more outlet streams from the one or more combustion reactors to preheat and/or vaporize the ammonia.

In some embodiments, the one or more combustion reactors are configured to (i) heat or preheat ammonia and (ii) provide the heated or preheated ammonia to one or more electric reactors or one or more combustion reactors for processing the ammonia to produce hydrogen.

In some embodiments, the system further comprises one or more fuel cells.

In some embodiments, the one or more fuel cells are configured to process (i) hydrogen produced by the one or more electric reactors and/or (ii) hydrogen produced by the one or more combustion reactors to generate electricity.

In some embodiments, the one or more fuel cells are configured to produce one or more fuel cell outlet streams that include unconverted hydrogen.

In some embodiments, the combustion reactor or reactors are configured to utilize unconverted hydrogen as a combustion fuel to drive the decomposition of ammonia and sustain self-sustaining autothermal reforming.

In some embodiments, multiple reactors are arranged in a series configuration.

In some embodiments, multiple reactors are arranged in a parallel configuration.

In some embodiments, multiple reactors are arranged in a modular configuration.

In some embodiments, the system further comprises a control unit configured to control operation of the ammonia treatment device to regulate the fluid pressure at the inlet of the one or more fuel cells.

In some embodiments, the system further comprises a control unit configured to control operation of the ammonia treatment device to regulate fluid flow to the one or more fuel cells.

In some embodiments, the ammonia treatment device further comprises one or more valves, pumps, fans, blowers, or compressors for regulating the output or operation of the ammonia treatment device.

In some embodiments, the ammonia treatment device is configured to process ammonia for one or more mobile applications or platforms.

In some embodiments, the ammonia treatment device is configured to process ammonia for one or more fixed applications or platforms.

In some embodiments, the ammonia treatment device is configured to be attached, coupled, or mounted on a vehicle.

In some embodiments, the ammonia treatment device is configured to be integrated with one or more electrical or mechanical components of the vehicle.

In another aspect, the disclosure provides a method, the method including: (a) heating an electric reactor to a first target temperature; (b) reforming ammonia using the electric reactor to produce a fuel comprising at least hydrogen; (c) heating a combustion reactor to a second target temperature by combusting the fuel produced in (b); and (d) supplying additional ammonia to the combustion reactor, the combustion reactor configured to (i) decompose the additional ammonia to produce additional hydrogen and (ii) supply the additional hydrogen to one or more fuel cells.

In some embodiments, the combustion reactor is configured for self-sustaining autothermal reforming at the second temperature.

In some embodiments, the method further includes, subsequent to (c), shutting down the electric heater of the electric reactor.

In some embodiments, (c) further comprises shutting down the electric heater of the electric reactor.

In some embodiments, the method further includes controlling operation of the electric reactor based on the temperature of the combustion reactor or the ammonia conversion efficiency of the combustion reactor.

In some embodiments, the method further includes controlling the flow rate of ammonia to the electric reactor or the combustion reactor based on the temperature of the combustion reactor or the ammonia conversion efficiency of the combustion reactor.

In some embodiments, the method further includes controlling an outlet flow rate from the combustion reactor based on the temperature of the combustion reactor or the ammonia conversion efficiency of the combustion reactor.

In some embodiments, the method further includes controlling the air flow rate to the combustion reactor based on the temperature of the combustion reactor or the ammonia conversion efficiency of the combustion reactor.

In some embodiments, the method further includes, subsequent to (d), directing the outlet stream from the one or more fuel cells to a combustion reactor to facilitate further decomposition of the ammonia.

In some embodiments, the outlet stream from one or more fuel cells includes unconverted hydrogen.

In some embodiments, the method further includes controlling the air flow rate or the ammonia flow rate to the combustion reactor to reach or maintain a predetermined temperature range.

In some embodiments, the method further comprises preheating the ammonia prior to (b) and/or (c).

In some embodiments, the ammonia is preheated using a combustion reactor or an electric reactor.

In some embodiments, the ammonia is preheated using the exit stream from the combustion reactor.

In some embodiments, the ammonia is preheated using combustion product gases.

In some embodiments, heat is exchanged between the ammonia and the combustion product gases in a countercurrent or parallel flow manner.

Another aspect of the present disclosure provides a non-transitory computer-readable medium including machine-executable code that, when executed by one or more computer processors, performs any of the methods described above or elsewhere herein.

Another aspect of the present disclosure provides a system comprising one or more computer processors and a computer memory coupled thereto. The computer memory includes machine executable code that, when executed by the one or more computer processors, performs any of the methods described above or elsewhere herein.

Other aspects and advantages of the present disclosure will become readily apparent to those skilled in the art from the following detailed description, in which only exemplary embodiments of the present disclosure are shown and described. As will be understood, the present disclosure is capable of other and different embodiments, and its several details are capable of modification in various obvious respects, all without departing from the present disclosure. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.

INCORPORATION BY REFERENCE All publications, patents, and patent applications mentioned in this specification are incorporated herein by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. To the extent that the publications and patents or patent applications incorporated by reference conflict with the disclosure contained in the specification, the specification supersedes and/or takes precedence over any such conflicting content.

The novel features of the invention are set forth with particularity in the appended claims. The features and advantages of the invention will be better understood by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings (also referred to herein as "figures"), in which:

FIG. 1 illustrates generally an exemplary system for processing ammonia to produce hydrogen fuel, according to one or more embodiments of the present disclosure.

FIG. 2 illustrates a schematic of an exemplary method of hydrogen storage using liquid chemicals, according to one or more embodiments of the present disclosure.

FIG. 3 illustrates a schematic of the use of ammonia as a hydrogen carrier in accordance with one or more embodiments of the present disclosure.

FIG. 4 shows a schematic of ammonia as an energy carrier and its various density characteristics compared to other types of fuels.

5 illustrates a schematic of a power system that uses ammonia as a fuel for a fuel cell, in accordance with one or more embodiments of the present disclosure. In one or more embodiments of the present disclosure, the power system may comprise a proton exchange membrane fuel cell (PEMFC).

FIG. 6 illustrates a schematic of an exemplary ammonia power pack system configuration according to one or more embodiments of the present disclosure.

FIG. 7A illustrates a schematic of an example of an electrically heated, fast start-up reactor according to one or more embodiments of the present disclosure.

FIG. 7B illustrates a schematic of an example of an electrically heated fast start-up reactor with one or more conductive springs, according to one or more embodiments of the present disclosure.

FIG. 8 illustrates a schematic plot of gas temperature as a function of time for a fast start reactor with one or more conductive springs, in accordance with one or more embodiments of the present disclosure.

FIG. 9 illustrates generally various modifications and treatments of catalyst materials that can be used in fast start-up reactors according to one or more embodiments of the present disclosure.

FIG. 10 illustrates a schematic of start-up time simulation data for a start-up reactor, according to one or more embodiments of the present disclosure.

FIG. 11 illustrates a schematic of start-up reactor ammonia conversion simulation data according to one or more embodiments of the present disclosure.

FIG. 12 illustrates a schematic of an example of a modular design of the start-up reactor, according to one or more embodiments of the present disclosure.

FIG. 13 illustrates a schematic of start-up reactor transient time and transient reactor temperature data in accordance with one or more embodiments of the present disclosure.

FIG. 14 illustrates a schematic of an example of a primary reactor with hybrid heating, according to one or more embodiments of the present disclosure.

15A and 15B show schematic diagrams of reactor thermal reforming efficiency, heat absorption rate, hydrogen combustion rate, and fuel cell power output data for the present systems and methods in accordance with one or more embodiments of the present disclosure. Ibid.

FIG. 16 illustrates a schematic of hybrid heating simulation data for the present system and method, in accordance with one or more embodiments of the present disclosure.

FIG. 17 illustrates a schematic of heating power ratio simulation data for the present system and method, in accordance with one or more embodiments of the present disclosure.

FIG. 18 illustrates generally a computer system that is programmed or otherwise configured to implement the present systems and methods, in accordance with one or more embodiments of the present disclosure.

19-25 generally illustrate various examples of system configurations for ammonia processing and ammonia power pack systems in accordance with one or more embodiments of the present disclosure. Ibid. Ibid. Ibid. Ibid. Ibid. Ibid.

26-35 generally illustrate various exemplary configurations for packaging and assembly of an ammonia power pack system in accordance with one or more embodiments of the present disclosure. Ibid. Ibid. Ibid. Ibid. Ibid. Ibid. Ibid. Ibid. Ibid.

36A-36C illustrate schematic configurations for supplying combustible hydrogen gas to a combustor, according to one or more embodiments of the present disclosure. Ibid.

37A-37C illustrate schematic configurations for supplying air to a combustor according to one or more embodiments of the present disclosure. Ibid.

38A and 38B illustrate schematic diagrams of a combustor design for contacting air and fuel according to one or more embodiments of the present disclosure.

FIG. 39 illustrates a schematic of a combustor design having multiple air-fuel contact points in accordance with one or more embodiments of the present disclosure.

40A and 40B show schematic exterior and interior cross-sectional views of a combustor and reactor design according to one or more embodiments of the present disclosure.

FIG. 40C illustrates a schematic of a system including a combustor configured for combustion inside a reactor, according to one or more embodiments of the present disclosure.

FIG. 40D shows a photograph of a system including a combustor configured for combustion inside a reactor, according to one or more embodiments of the present disclosure.

41A and 41B show experimental measurements of reactor thermal reforming efficiency and combustor efficiency as a function of _NH3 flow rate performed on the design shown in FIG. Ibid.

FIG. 42 illustrates a schematic of a design with two combustors partially embedded within a reactor, according to one or more embodiments of the present disclosure.

FIG. 43 illustrates a temperature profile solved in a simulation for a combustor design in accordance with one or more embodiments of the present disclosure.

FIG. 44 illustrates a temperature profile solved in a simulation for a combustor design in accordance with one or more embodiments of the present disclosure.

45A and 45B show temperature profiles of a simulated combustor design in accordance with one or more embodiments of the present disclosure.

46A and 46B show temperature and hydrogen mass profiles of a simulated combustor design in accordance with one or more embodiments of the present disclosure. Ibid.

FIG. 47 illustrates a schematic of an exemplary design of a combustor and reactor, according to one or more embodiments of the present disclosure.

FIG. 48 illustrates generally an exemplary design of a combustor and reactor in accordance with one or more embodiments of the present disclosure.

FIG. 49 illustrates generally an example of a system architecture for an ammonia processing system according to one or more embodiments of the present disclosure.

FIG. 50 shows a digital rendering of an ammonia power pack system according to one or more embodiments of the present disclosure.

FIG. 51 illustrates a digital rendering of an ammonia power pack system mounted on an air vehicle according to one or more embodiments of the present disclosure.

FIG. 52 illustrates an ammonia power pack system installed in an air vehicle according to one or more embodiments of the present disclosure.

FIG. 53 illustrates an air vehicle in flight while powered by an ammonia power pack system according to one or more embodiments of the present disclosure.

FIG. 54 illustrates the power profile of an air vehicle equipped with an ammonia power pack system according to one or more embodiments of the present disclosure.

55A and 55B generally illustrate exterior and interior views of a reactor having a circular cross-section, according to one or more embodiments of the present disclosure.

FIG. 56 generally illustrates a top view and an inside view of a reactor having a circular cross-section, according to one or more embodiments of the present disclosure.

57A and 57B show schematic exterior and interior views of a reactor having a square cross-section according to one or more embodiments of the present disclosure.

58A and 58B generally show top and inside views of a reactor having a square cross-section, according to one or more embodiments of the present disclosure.

59A and 59B show schematic diagrams of exterior and interior views of a reactor having both high temperature and low temperature efficient catalysts, according to one or more embodiments of the present disclosure.

FIG. 60 illustrates a schematic of the gas flow paths in a reactor flow path according to one or more embodiments of the present disclosure.

FIG. 61 shows digital renderings of reactors having various shapes and configurations, according to one or more embodiments of the present disclosure.

62A-62D show digital renderings of various reactor designs with different dimensions, according to one or more embodiments of the present disclosure.

63A and 63B illustrate schematic diagrams of the thermal reforming efficiency and ammonia conversion of a reactor as a function of ammonia flow rate through the reactor, according to one or more embodiments of the present disclosure.

64A and 64B illustrate generally a system configuration for processing ammonia during start-up and operation in accordance with one or more embodiments of the present disclosure. Ibid.

FIG. 65 illustrates generally a system configuration for processing ammonia during start-up, according to one or more embodiments of the present disclosure.

FIG. 66 illustrates generally a system configuration for processing ammonia during operation in accordance with one or more embodiments of the present disclosure.

FIG. 67 illustrates a schematic of an example of a system reactor and/or hot box configuration according to one or more embodiments of the present disclosure.

FIG. 68 illustrates generally an example of a system reactor and/or hot box configuration according to one or more embodiments of the present disclosure.

FIG. 69 illustrates a schematic of an example of a system reactor and/or hot box configuration according to one or more embodiments of the present disclosure.

FIG. 70 illustrates generally an example of a system reactor and/or hot box configuration during start-up, according to one or more embodiments of the present disclosure.

FIG. 71 illustrates generally an example of a system reactor and/or hot box configuration during start-up, in accordance with one or more embodiments of the present disclosure.

FIG. 72 illustrates generally an example of a system reactor and/or hot box configuration in operation, according to one or more embodiments of the present disclosure.

FIG. 73 illustrates generally an example of a system reactor and/or hot box configuration in operation, according to one or more embodiments of the present disclosure.

FIG. 74 illustrates a combustion burner head design according to one or more embodiments of the present disclosure.

75A-75B show a burner head design according to one or more embodiments of the present disclosure.

76A-76B show a burner head design according to one or more embodiments of the present disclosure.

FIG. 77 illustrates a fluid simulation within a combustion tube with a burner head according to one or more embodiments of the present disclosure.

FIG. 78 illustrates a fluid simulation within a combustion tube with a burner head according to one or more embodiments of the present disclosure.

FIG. 79 illustrates a fluid simulation within a combustion tube with a burner head according to one or more embodiments of the present disclosure.

FIG. 80A shows a power pack according to one or more embodiments of the present disclosure.

FIG. 80B illustrates a schematic of a tractor having an attached power pack in accordance with one or more embodiments of the present disclosure.

81A-81B show the voltage vs. current and power vs. current, respectively, of an integrated power pack with a fuel cell.

FIG. 82 shows a block diagram for system control using a controller according to one or more embodiments of the present disclosure.

FIG. 83 shows a process flow diagram of a start-up process according to one or more embodiments of the present disclosure.

FIG. 84 shows a process flow diagram of a start-up process according to one or more embodiments of the present disclosure.

FIG. 85 shows a process flow diagram of a start-up process according to one or more embodiments of the present disclosure.

FIG. 86 shows a process flow diagram of a start-up process according to one or more embodiments of the present disclosure.

FIG. 87 illustrates a process flow diagram of a post-start-up operational process according to one or more embodiments of the present disclosure.

FIG. 88 illustrates a process flow diagram of a post-start-up operational process according to one or more embodiments of the present disclosure.

While various embodiments of the present invention have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will occur to those skilled in the art without departing from the invention. It will be appreciated that various alternatives to the embodiments of the invention described herein may be employed.

When the terms "at least," "greater," or "greater than or equal to" appear after the last number in a series of two or more numbers, the terms "at least," "greater than," or "greater than or equal to" may always apply to each number in the series. For example, 1, 2, or 3 or more can be equivalent to 1 or more, 2 or more, or 3 or more.

When the term "less than", "less than", or "less than" follows the last number in a series of two or more numbers, the term "less than", "less than", or "less than" may apply to each number in the series. For example, 3, 2, or 1 or less can be equivalent to 3 or less, 2 or less, or 1 or less.

The terms "at least one of A and B" and "at least one of A or B" can be understood to mean A only, B only, or both A and B. The term "A and/or B" can be understood to mean A only, B only, or both A and B.

The terms "real-time" or "real-time," as used interchangeably herein, generally refer to an event (e.g., an operation, process, method, technique, calculation, computation, analysis, visualization, optimization, etc.) that can be performed using recently obtained (e.g., collected or received) data. In some cases, a real-time event may be performed nearly instantly or within a sufficiently short time period, e.g., within at least 0.0001 milliseconds (ms), 0.0005 ms, 0.001 ms, 0.005 ms, 0.01 ms, 0.05 ms, 0.1 ms, 0.5 ms, 1 ms, 5 ms, 0.01 seconds, 0.05 seconds, 0.1 seconds, 0.5 seconds, 1 second, or more. In some cases, real-time events may occur almost instantly or within a sufficiently short time, for example, up to 1 second, 0.5 seconds, 0.1 seconds, 0.05 seconds, 0.01 seconds, 5 ms, 1 ms, 0.5 ms, 0.1 ms, 0.05 ms, 0.01 ms, 0.005 ms, 0.001 ms, 0.0005 ms, 0.0001 ms, or less.

The terms "decompose," "dissociate," "reform," "crack," and "chemically change" and grammatical variations thereof may be construed interchangeably. For example, the expression "decomposition of ammonia" may be interchangeably used with "dissociation of ammonia," "reformation of ammonia," "cracking of ammonia," etc.

The terms "heater," "heating element," and "heating unit," and grammatical variations thereof, can be construed interchangeably. For example, the expression "electric heater" can be interchangeably used with "electric heating unit," "electric heating element," etc.

The terms "fired heater" and "combustor," and their grammatical variations, may be construed interchangeably.

The terms "reactor," "reformer," "reactor module," and grammatical variations thereof may be construed interchangeably. For example, the expression "electric reactor" may be interchangeably used with "electric reactor module."

The terms "combustion reactor", "combustion heating reactor", "combustor reactor", and "C reactor", and grammatical variations thereof, may be construed interchangeably.

The terms "electric reactor", "electrically heated reactor", and "E reactor", as well as grammatical variations thereof, may be construed interchangeably.

The terms "controller" and "control unit" and their grammatical variations may be construed interchangeably.

The terms "ammonia conversion," "ammonia conversion rate," and "ammonia conversion efficiency," and grammatical variations thereof, can be interpreted as the percentage of ammonia that is converted to hydrogen and nitrogen and can be interpreted interchangeably. For example, an "ammonia conversion," "ammonia conversion rate," or "ammonia conversion efficiency" of 90% can represent that 90% of the ammonia is converted to hydrogen and nitrogen.

The term "autothermal reforming" can be interpreted as a condition where the ammonia decomposition reaction ( _2NH3 → _N2 +3H2; endothermic reaction) is heated by a hydrogen combustion reaction ( _2H2 + _O2 → _2H2O ; _exothermic reaction) using at least a portion of the hydrogen produced by the ammonia decomposition reaction itself. In some cases, the term "autothermal reforming" can be interpreted as a condition where the ammonia decomposition reaction is heated by a hydrogen combustion reaction using at least a portion of the hydrogen produced by the ammonia decomposition reaction itself, electrical heating, or a combination of both, which may result in an overall positive electrical and/or chemical energy output. For example, when "autothermal reforming" is carried out using a hydrogen combustion reaction and/or electrical heating, the hydrogen produced from the ammonia decomposition reaction may be sufficient to provide the combustion fuel and the hydrogen combustion reaction, and/or electrical energy for electrical heating by a hydrogen-to-electricity conversion device (e.g., fuel cell, combustion engine, etc.). In some cases, the hydrogen provided for the hydrogen combustion reaction and/or the power provided for electrical heating to perform "autothermal reforming" may or may not use hydrogen from the ammonia decomposition reaction (e.g., hydrogen may be provided by another hydrogen source, electricity may be provided from a battery or power grid, etc.). In some cases, "autothermal reforming" may be interpreted as a condition where the ammonia decomposition reaction is heated by a combustion reaction (e.g., ammonia combustion, hydrocarbon combustion, etc.), electrical heating, or a combination of both, which may result in an overall positive electrical energy and/or chemical energy output. For example, when "autothermal reforming" is performed using a combustion reaction and/or electrical heating, the chemical energy (e.g., lower heating value) from the hydrogen made from the ammonia decomposition reaction may be higher than the chemical energy (e.g., lower heating value) of the combustion fuel and/or may be sufficient to provide electrical energy for electrical heating by a hydrogen-to-electricity conversion device (e.g., fuel cell, combustion engine, etc.).

Reactor

In one aspect, the present disclosure provides a system for processing a source material. The system may include a reactor or reformer. The source material may be processed to produce a fuel source. The fuel source may include, for example, hydrogen and/or nitrogen. The fuel source may be fed to one or more hydrogen fuel cells having one or more air intakes, and may be configured to generate electrical energy using the fuel source. Such electrical energy may be used to power various systems, vehicles, and/or devices.

Additionally or alternatively, the fuel source may be provided to one or more internal combustion engines (ICEs), which may be configured to consume the fuel source to generate mechanical energy (to power a drivetrain, propellers, or other propulsion device) and/or electrical energy (to power a power grid or batteries). The fuel source may be provided to the ICE in combination with another fuel such that the ICE operates as a dual-fuel (DF) engine. For example, a DF ICE may burn hydrogen with ammonia, hydrogen with diesel, hydrogen with natural gas, etc.

FIG. 1 illustrates a schematic block diagram of an exemplary method for processing a feed material to produce electrical energy, according to one or more embodiments of the present disclosure. The feed material 110 can be fed to a reactor 120. The feed material 110 may be a compound containing one or more hydrogen atoms. The compound may be, for example, ammonia (NH ₃ ). In some cases, the compound may include a hydrocarbon C _x H _y . The feed material 110 may be fed to a reactor 120. The feed material 110 may be in a gaseous and/or liquid state. The reactor 120 may be designed or configured to process the feed material 110 to extract, make, or release a fuel source 130 from the feed material 110. In some cases, processing the feed material 110 may include heating the feed material 110 using the systems and methods of the present disclosure to extract, make, or release a fuel source 130. The fuel source 130 may include hydrogen and/or nitrogen. The fuel source 130 may be fed to one or more fuel cells for the generation of electrical energy. Such electrical energy may be used to power a variety of systems, vehicles, and/or devices, including, for example, land, air, or underwater vehicles.

As described above, one or more fuel cells can be used to generate electrical energy from a fuel source 130, which can include hydrogen and/or nitrogen. In some cases, the one or more fuel cells can generate electricity by an electrochemical reaction between the fuel source 130 and oxygen (O ₂ ). The fuel may include hydrogen and/or nitrogen in the fuel source 130. The electricity generated by the fuel cell can be used to power one or more systems, vehicles, or devices. In some embodiments, excess electricity generated by the fuel cell can be stored in one or more energy storage units (e.g., batteries) for future use. In some optional embodiments, the fuel cell can be provided as part of a larger electrochemical system. The electrochemical system can further include an electrolysis module. Electrolysis of a by-product (e.g., water) of one or more fuel cells can allow for the removal of the by-product by breaking it down into one or more components (e.g., oxygen and/or hydrogen). Electrolysis of the by-product can also generate another fuel (e.g., hydrogen) for the one or more fuel cells. In some embodiments, the one or more fuel cells can be operated as multiple fuel cells (i.e., an array of fuel cells) such that the output power is scalable (e.g., 50 kilowatts, 500 kilowatts, or even multiple megawatts). In any of the embodiments described herein, the one or more fuel cells can be configured to receive hydrogen from a hydrogen source. The hydrogen source may include one or more reactors or reformers, as described elsewhere herein. In some non-limiting embodiments, the hydrogen source may not or need not include a reactor or reformer. For example, the hydrogen source may include a hydrogen storage tank. The hydrogen storage tank may or may not be in fluid communication with a reactor or reformer. In some cases, the hydrogen source may include a hydrogen production system or subsystem. In any of the embodiments described herein, the one or more fuel cells are configured to output electrical energy and/or provide an outlet stream to one or more reactors, reformers, heat exchangers, or any other components of the system described herein to facilitate the ammonia decomposition process, regardless of the type of hydrogen source used to provide or supply hydrogen to the one or more fuel cells.

FIG. 2 illustrates a schematic of an exemplary method of hydrogen storage using liquid chemicals according to one or more embodiments of the present disclosure. Hydrogen can be stored using one or more liquid chemicals, whether produced by electrolysis of renewable energy (e.g., green hydrogen) or by hydrocarbon reforming (e.g., blue or gray hydrogen). In some non-limiting embodiments, the one or more liquid chemicals may include, for example, ammonia, liquid organic hydrogen carriers (LOHC), formic acid (HCOOH), or methanol (CH ₃ OH). The one or more liquid chemicals may be stored in a hydrogen-rich or hydrogen-lean form. The one or more liquid chemicals including hydrogen can be processed as described elsewhere herein to release the hydrogen stored in the liquid chemicals. Once released, the hydrogen may be used for power generation (e.g., stationary or portable power generation) or may be supplied to a hydrogen fueling station.

FIG. 3 illustrates a schematic of using ammonia as a hydrogen carrier according to one or more embodiments of the present disclosure. Hydrogenation can be used to store hydrogen in one or more liquid chemicals. Hydrogenation may refer to treating a material or substance with molecular hydrogen (H ₂ ) to add one or more pairs of hydrogen atoms to various constituent compounds (e.g., one or more unsaturated compounds) that make up the material or substance. Hydrogenation may be performed using a catalyst that allows the reaction to occur under conditions close to standard temperature and pressure (e.g., room temperature and sea level atmospheric pressure). In some cases, the Haber-Bosch process (an artificial nitrogen fixation process) may be used to make ammonia. The process can be used to convert atmospheric nitrogen (N 2 ) to ammonia (NH ₃ ) by reaction with hydrogen (e.g., H ₂ made or obtained by _electrolysis ) using a metal catalyst under high temperature and pressure.
_2NH3 ⇔ _N2 + _3H2

As described above, the Haber-Bosch process can be used to make ammonia that can be used as a hydrogen carrier. Using ammonia as a hydrogen carrier can provide several advantages over the storage and transportation of pure hydrogen, including easy storage at relatively standard conditions (0.8 MPa in the liquid state, 20° C.) and convenient transportation. Ammonia also has a relatively high hydrogen content (17.7% by weight or 120 grams of H ₂ per liter of liquid ammonia). Furthermore, the production of ammonia using the Haber-Bosch process can be powered by renewable energy sources (e.g., photovoltaic, solar thermal, wind turbines, and/or hydroelectric power), making the production process environmentally safe and friendly, since N ₂ is the only by-product and there are no additional emissions of CO _2. Once the ammonia is made, it can be processed to release hydrogen by a dehydrogenation process (i.e., by dissociating, decomposing, reforming, or cracking the ammonia). The released hydrogen can then be fed to one or more fuel cells, for example, proton exchange membrane fuel cells (PEMFCs) having a proton-conducting polymer electrolyte membrane (i.e., polymer electrolyte membrane [PEM] fuel cells). PEMFCs can have a relatively low operating temperature and/or pressure range (e.g., about 50-100° C.). Proton exchange membrane fuel cells can be used to convert chemical energy released during an electrochemical reaction of hydrogen and oxygen into electrical energy to create thermal energy, as opposed to direct combustion of hydrogen and oxygen gases. PEMFCs can operate on the opposite principle to PEM electrolysis, which produces electricity and consumes electricity. In some embodiments, the one or more fuel cells can be solid oxide fuel cells (SOFCs), high temperature PEMs (HTPEMs), or alkaline fuel cells (AFCs). The methods and systems disclosed herein can be implemented to achieve thermally efficient hydrogen production and can be extended for application to high energy density power systems.

FIG. 4 shows a schematic of ammonia as an energy carrier and various density characteristics of ammonia compared to other types of fuels. The _H2 storage capacity of _NH3 is about 17.7 wt. % and 120 grams of _H2 per liter of ammonia. Compared to other fuel types, e.g., hydrogen, ammonia exhibits favorable volumetric density given its gravimetric density. Furthermore, compared to other types of fuels (including carbon-based fuels, e.g., methane, propane, methanol, ethanol, gasoline, E-10 gasoline, JP-8 jet fuel, or diesel), the use of ammonia as a fuel produces no harmful exhaust emissions, e.g., _CO2 , CO, black carbon (soot), and zero or negligible emissions of _NOx (e.g., _NO2 and _N2O ) (e.g., especially when combined with selective catalytic reduction [SCR] catalysts). Thus, by using ammonia as an energy carrier, some embodiments of the systems and methods disclosed herein can take advantage of (a) the large volumetric density of ammonia compared to hydrogen, and (b) the ability to transport ammonia at standard temperatures and pressures without the need for the complex, high-pressure storage vessels typically used to store and transport hydrogen, while still taking advantage of the advantages of hydrogen fuel (e.g., environmentally safe and high gravimetric energy density) once ammonia is cracked into hydrogen.

In some cases, the ammonia may be contained or stored in a liquid fuel storage tank. In some cases, the ammonia may be stored as liquid ammonia. In some cases, the liquid ammonia may be stored at a temperature in the range of about 15 to about 30° C. and an absolute pressure in the range of 7 to 12 bar. In some cases, the liquid ammonia may be stored at a gauge pressure in the range of about atmospheric pressure to about 20 bar. In some cases, the liquid ammonia may be stored at a temperature in the range of about -40 to about 20° C. and an absolute pressure in the range of about 0.5 bar to about 9 bar. In some cases, the liquid ammonia may be stored at a temperature of at least about -60, -50, 40, -30, -20, -10, 0, 10, 20, 30, 40, 50, or 60 degrees Celsius. In some cases, the liquid ammonia may be stored at a temperature of up to about -60, -50, 40, -30, -20, -10, 0, 10, 20, 30, 40, 50, or 60 degrees Celsius. In some cases, the liquid ammonia may be stored at a pressure of at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, or 40 bar absolute. In some cases, the liquid ammonia may be stored at a pressure of up to about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, or 50 bar absolute.

FIG. 5 illustrates a schematic diagram of a power system that uses ammonia as a fuel source to generate hydrogen that is fed to one or more fuel cells (e.g., proton exchange membrane fuel cells [PEMFCs]) to generate electrical energy, according to one or more embodiments of the present disclosure. The power system may include a reformer configured to perform catalytic decomposition or cracking of the ammonia to extract and/or create hydrogen. Such a reformer may be operated using thermal energy. In some cases, the power system may include a combustor that generates thermal energy to drive the operation of the reformer. In some cases, the thermal energy may be generated from the combustion of chemical compounds (e.g., hydrogen or hydrocarbons). The hydrogen generated and/or extracted using the reformer may be fed to one or more fuel cells, which create electrical energy to power one or more systems, subsystems, or devices that require electrical energy to operate. In some cases, the hydrogen generated and/or extracted using the reformer may be fed to one or more other reactors or reformers. In such cases, the one or more other reactors or reformers may be configured to combust hydrogen to generate thermal energy. Such thermal energy is used to heat one or more other reactors or reformers to facilitate additional catalytic decomposition or cracking of ammonia to extract and/or produce additional hydrogen.

Fast start reactor module

In some embodiments, the disclosed system may include a power pack and a load following module. The power pack and the load following module may facilitate catalytic heat transfer, faster reactor start-up times, and optimized thermal management, packaging optimization, and dynamic load following. In some cases, the power pack may include a load following module that enables fast start-up. Such a load following module may be integrated with one or more structural elements or subsystems of the power pack. The load following reactors described herein may be configured to adjust the power output (e.g., of the fuel cell) based on the demand for power (e.g., at an electrical load coupled to the fuel cell), and may adjust the power output fast enough to avoid the use of additional battery systems. Such demand may be determined based on feedback provided by one or more end users operating the system or device requiring power, or based on one or more sensor readings indicating insufficient power or a need for additional power. The one or more sensor readings are obtained using one or more sensors provided on or operably coupled to the system or device that operates using the electrical energy generated by the one or more fuel cells (which consume the hydrogen produced by the reactor).

FIG. 6 illustrates a schematic diagram of an exemplary ammonia power pack system configuration according to one or more embodiments of the present disclosure. The system configuration may include a power pack and a load following module, as described above. In some cases, the system may have a system level energy density of at least about 600 watt-hours/kilogram. In some cases, the system may have a hydrogen storage capacity of at least about 5% by weight. The system illustrated in FIG. 6 may include a start-up reactor R_s. Ammonia may be supplied to the start-up reactor via one or more fuel lines. The flow of ammonia to the start-up reactor may be controlled using one or more flow control units FCU and/or one or more valves SV (e.g., solenoid valves). The start-up reactor R_s may be configured to directly heat the catalyst using resistive heating (i.e., by passing an electric current through the catalyst itself or through the catalyst support). This particular configuration may reduce thermal mass and generate heat at the location where the reaction or reactions occur, thereby reducing the start-up time required to reach a desired reaction temperature for ammonia decomposition. In some embodiments, the desired temperature may range from about 400 degrees Celsius to about 600 degrees Celsius. The heat generated using the start-up reactor R_s can be used to heat the catalyst or a portion thereof. The heat generated using the start-up reactor R_s can also be used to decompose or crack a portion of the ammonia to produce hydrogen, which may be fed directly to one or more fuel cells for producing electricity. In some cases, the hydrogen produced from the decomposition of ammonia may be combusted to heat the main reactor R_m. In some cases, the heat generated using the start-up reactor R_s may be used to heat the main reactor R_m or a portion thereof. In such cases, the start-up reactor R_s and the main reactor R_m may be in thermal communication with each other to allow the transfer of thermal energy between the two reactors. The main reactor R_m may include one or more heating units. The one or more heating units may include, for example, electric heaters and/or fired heaters. The heat generated using the start-up reactor R_s may be used to supplement the heat generated using the electric heaters and/or fired heaters of the main reactor R_m. The main reactor R_m can be configured to decompose ammonia fed to the system to produce and/or extract hydrogen from the ammonia using heat generated using an electric heater, a combustion heater, the start-up reactor R_s, and/or the combustion of any hydrogen produced using the start-up reactor R_s. The extracted hydrogen may be fed to one or more fuel cells FC for the production of electrical energy. In some cases, an adsorption tower ADS can be used to process (e.g., purify or purify) the hydrogen before it is fed to the one or more fuel cells. The electricity produced using the hydrogen and one or more fuel cells can be used to power an electrical load (e.g., an air vehicle, e.g., a drone or an aircraft).

In some cases, the main reactor R_m and the startup reactor R_s may be configured to receive ammonia from the same source. The same source may be in fluid communication with both the main reactor R_m and the startup reactor R_s (e.g., via separate piping, ducts, or flow paths). Alternatively, the same source may be in fluid communication with the main reactor R_m through the startup reactor R_s, or with the startup reactor R_s through the main reactor R_m. In other cases, the main reactor R_m and the startup reactor R_s may be configured to receive ammonia from different sources. In such cases, the main reactor R_m may be configured to receive ammonia from a first source, and the startup reactor R_s may be configured to receive ammonia from a second source. The first and second sources may or may not be in fluid communication with each other. In some cases, the main reactor R_m and/or the startup reactor R_s may be configured to receive ammonia from multiple sources.

7A illustrates a schematic diagram of an example of a fast start-up reactor according to one or more embodiments of the present disclosure. Such a fast start-up reactor may correspond to and/or comprise the start-up reactor R_s illustrated in FIG. 6. The fast start-up reactor may comprise a housing having electrical insulation and/or thermal insulation. The housing may be cylindrical or tubular in shape. The housing may have a cross-sectional shape. The cross-sectional shape may be a circle, an ellipse, an oval, or any polygon having three or more sides. The housing may comprise, for example, a ceramic material, such as quartz, or a metallic material, such as aluminum or steel.

The housing may include an interior volume that contains a catalyst bed and/or one or more electrodes (e.g., one or more copper electrodes). The one or more electrodes may be in electrical communication with the catalyst bed or a portion thereof. The housing may include an enclosed or partially enclosed volume configured to contain a gas (e.g., ammonia) and enable processing of the gas. If the gas includes ammonia, such processing may include cracking or decomposing the ammonia (or a portion of the ammonia). The fast start reactor may include a gas inlet configured to receive the ammonia. The fast start reactor may further include a catalyst bed including one or more catalysts. The one or more catalysts may include, for example, a modified metal foam catalyst. Another type of catalyst material compatible with the fast start reactor may be used. The catalyst material may be or may have undergone one or more strengthening and/or treatments (FIG. 9). In some cases, the metal foam catalyst may include nickel chromium aluminum (NiCrAl) foam. The fast start reactor may further include a gas outlet configured to direct one or more gases (e.g., ammonia, nitrogen, and/or hydrogen) to another system or subsystem. In some cases, the gas outlet may be configured to direct hydrogen gas produced by the fast start reactor to one or more fuel cells. In some cases, the gas outlet can be configured to direct the hydrogen-nitrogen or hydrogen-nitrogen-ammonia mixture to a gas inlet of the main reactor R_m shown and described in FIG. 6. In other cases, the gas outlet can be configured to direct the hydrogen gas produced by the fast start reactor to one or more combustors to generate thermal energy that can be used to power or heat the main reactor R_m shown and described in FIG. 6.

FIG. 7B illustrates a schematic of an example of a fast start-up reactor with one or more conductive springs according to one or more embodiments of the present disclosure. The one or more conductive springs may be provided adjacent to the catalyst bed. In some cases, the one or more conductive springs may be provided at both ends of the catalyst bed. The one or more conductive springs may be in physical, electrical, and/or thermal communication with the catalyst bed and/or one or more electrodes. The one or more conductive springs may be configured to reduce thermal stress on the foam catalyst when the foam catalyst undergoes thermal cycling. The one or more conductive springs may be configured to accommodate thermal expansion during heating of the catalyst and thermal contraction during cooling of the catalyst. The one or more conductive springs may function to reduce and/or redistribute mechanical loads on the catalyst bed such that the catalyst bed can withstand multiple thermal cycles without breaking or fracturing. In some cases, the one or more springs may be configured to reduce thermal stress on the catalyst due to thermal expansion or contraction of the catalyst during one or more thermal cycling procedures. The one or more springs may include, for example, copper or steel springs. The use of one or more conductive springs allows the start-up reactor to provide fast start-up capability while reducing or minimizing thermal stresses on the catalyst bed during rapid temperature changes.

8 is a schematic diagram of a plot of gas temperature as a function of time for a fast start reactor with one or more conductive springs as shown in FIG. 7. In some cases, a fast start reactor with one or more heat springs can be used to heat ammonia gas to 500 degrees Celsius in less than 5 minutes. In some cases, a fast start reactor with one or more heat springs can be used to heat ammonia gas to about 600 degrees Celsius in less than 60 minutes. In some cases, when 112 watts of heating power are provided to the catalyst, ammonia gas can be heated to 500 degrees Celsius in less than 300 seconds. In some cases, when 157 watts of heating power are provided to the catalyst, ammonia gas can be heated to 500 degrees Celsius in less than 200 seconds.

9 illustrates a schematic of various types of enhancements and/or treatments of metal foam catalyst materials that can be used in fast start-up reactors according to one or more embodiments of the present disclosure. Suitable metal foam catalysts may include any metal alloy including nickel, chromium, iron, and/or aluminum, i.e., Ni/Cr-X, Ni/Cr-X/Al-Y, and/or Ni/Fe-X/Cr-Y/Al-Z, where X, Y, and/or Z range from 0 to 100. The surface of the metal foam catalyst can be treated (e.g., by etching, alloying, leaching, and/or using one or more acid treatments) to increase the surface area of the catalyst material. The metal foam catalyst can also be subjected to a catalyst coating operation (e.g., by impregnation, PVD, or CVD) and/or one or more heat treatment operations (e.g., sintering, annealing, and/or calcination). Such processing of the metal foam catalyst material can produce a catalyst-coated metal foam that includes one or more electrically resistive catalysts.

Figure 10 shows a schematic of start-up time simulation data for the disclosed systems and methods. As used herein, start-up time can correspond to the amount of time required to increase the temperature of the reactor bed to a target temperature. The target temperature may be at least about 100 degrees Celsius, 200 degrees Celsius, 300 degrees Celsius, 400 degrees Celsius, or more. For reactor systems with fast start-up reactors as disclosed herein, the average reactor temperature can be increased to the target temperature in less time than other conventional reactor systems. For example, when the heating power of the disclosed system is adjusted to at least about 150 watts for direct resistive heating of the catalyst bed, the reactor and/or catalyst bed is heated to a target temperature of at least about 400 degrees Celsius in less than 30 seconds.

11 shows ammonia conversion efficiency simulation data of the disclosed system and method. As used herein, ammonia conversion efficiency can correspond to the percentage (by mass or moles) of ammonia converted to one or more constituents (e.g., hydrogen or nitrogen). For a reactor system with a fast start-up reactor as disclosed herein, the ammonia conversion efficiency can be higher than that of other conventional reactor systems. For example, when the heating power of the disclosed start-up reactor is adjusted to at least about 250 watts for direct resistance heating of the catalyst bed, the disclosed system can achieve an ammonia conversion efficiency of more than 90%, indicating that more than 90% of the ammonia is converted to one or more constituents in less than one minute.

FIG. 12 illustrates a schematic example of a modular design of a start-up reactor according to one or more embodiments of the present disclosure. In some cases, the start-up reactor may include a modular design that allows multiple layers with multiple reactor flow paths to be stacked on top of each other. Each of the layers may include a metal foam catalyst and an insulating material (e.g., thermal and/or electrical insulator). In some cases, a separator may be provided between one or more layers. In some cases, the separator may be electrically insulated using an electrically insulating coating, such as boron nitride (BN) or other ceramic-based material. The multiple layers may be arranged such that the gas inlet and gas outlet of each layer are aligned on one side. Furthermore, the multiple layers may be arranged such that the corresponding electrodes of each layer protrude inwardly or outwardly from the same side. The gas inlet and gas outlet may be provided on a first side of each layer, and the electrodes may be provided on a second side of each layer. The stackable modular design illustrated in FIG. 12 may improve the scalability of the start-up reactor and allow for direct heating of the metal foam catalyst. The modular configuration may also reduce the distance between the catalyst material and the one or more heat sources of each layer. In some embodiments, a metal housing with electrical insulation (e.g., an insulating coating including boron nitride) can be used to improve the heating performance and ammonia conversion efficiency of the start-up reactor.

Figure 13 shows a schematic of the transient time and transient reactor temperature data for the modular start-up reactor design. The transient time required to reach the target temperature may be more than a single reactor unit due to the larger thermal capacity of the modular start-up reactor design, but the modular start-up reactor design may still reach a target temperature of about 500 degrees Celsius in less than about 5 minutes. In some cases, if 112 watts of heating power is provided, the reactor can be heated to 500 degrees Celsius in less than about 300 seconds. In some cases, if 157 watts of heating power is provided, the reactor can be heated to 500 degrees Celsius in less than about 200 seconds.

In one aspect, the present disclosure provides a system including a first reactor module configured to receive a feed material including ammonia. The first reactor module may include a first catalyst and a start-up heating and reforming unit. The start-up heating and reforming unit may include one or more electrodes for passing an electric current through the first catalyst to heat the first catalyst (e.g., by resistive heating or Joule heating). The one or more electrodes may include, for example, one or more copper electrodes. In some cases, the first catalyst may be used to produce hydrogen from ammonia when the first catalyst is heated using the start-up heating and reforming unit.

In some embodiments, the system may further include a second reactor module in thermal and/or fluid communication with the first reactor module. The second reactor module may include a second catalyst and one or more main heating units for heating the second catalyst. In some cases, at least one of the one or more main heating units may be configured to heat at least a portion of the second catalyst based on combustion of hydrogen produced by the first reactor module. In some cases, the second catalyst may be used to produce hydrogen from ammonia when the second catalyst is heated using the one or more main heating units. In some embodiments, the one or more main heating units may include, for example, an electric heater and/or a fired heater.

As mentioned above, the system may include a first reactor module and a second reactor module. As used herein, the term "module" generally refers to a functional unit for performing one or more steps of a process (e.g., an ammonia cracking or decomposition process). A module may include one or more functional units. In some cases, a module may include a reactor or reformer. In some cases, the reactor or reformer may include a catalyst and/or one or more heating units for heating the catalyst. In some cases, the reactor or reformer may include at least one fluid input and/or at least one fluid output. At least one fluid input may be used to transport ammonia to the reactor or reformer. At least one fluid output may be used to transport hydrogen (or a mixture of hydrogen and nitrogen, optionally with trace ammonia) to one or more fuel cells.

In some cases, at least one of the first catalyst and the second catalyst may include a metal foam catalyst. The metal foam catalyst may include nickel, iron, chromium, and/or aluminum. In some cases, the metal foam catalyst may include one or more alloys including nickel, iron, chromium, and/or aluminum.

In some embodiments, the metal foam catalyst may include a catalytic coating of one or more powder or pellet catalysts. The catalytic coating may include a metal material, a promoter material, and/or a support material. In some embodiments, the metal foam catalyst may be porous such that the inner surface of the metal foam catalyst is covered by the catalytic coating. The metal material may include, for example, ruthenium, nickel, rhodium, iridium, cobalt, iron, platinum, chromium, palladium, and/or copper. In some embodiments, the promoter material may include at least one material selected from Li, Na, K, Rb, Cs, Mg, Ca, Ba, Sr, La, Ce, Pr, Sm, or Gd. In some embodiments, the support may _comprise at _least one material selected from _Al2O3 , _MgO , _CeO2 , _ZrO2 , _La2O3 , _SiO2 , _Y2O3 , _TiO2 , SiC, hexagonal BN (boron nitride), BN nanotubes, silicon carbide, one or more _zeolites , _LaAlO3 , _CeAlO3 , _MgAl2O4 , _CaAl2O4 , or one or more carbon nanotubes _.

In some embodiments, the catalyst coating may include one or more ruthenium-based precursors. The one or more ruthenium-based precursors may include, for example, _RuCl3 or _Ru3 (CO) ₁₂ . In any of the embodiments described herein, the metal foam catalyst may have an apparent electrical resistivity of at least about 8 microohm-meters (μΩm).

In some cases, the metal foam catalyst may be treated using one or more etching, alloying, leaching, or acid treatments to increase the surface area of the metal foam catalyst. In some cases, the metal foam catalyst may be heat treated (e.g., by sintering, calcining, and/or annealing). In some cases, the metal foam catalyst may be coated using physical vapor deposition and/or chemical vapor deposition processes. In some embodiments, the first reactor module may comprise a plurality of modular units stackable together. Each of the plurality of modular units may comprise a metal foam catalyst and one or more reactor flow paths for directing ammonia to the metal foam catalyst. The one or more reactor flow paths may comprise any suitable design or configuration that allows ammonia gas to be directed to a surface or interior volume of the metal foam catalyst. In some cases, the system may further comprise one or more insulation panels for separating the plurality of modular units. The plurality of modular units (and the metal foam catalyst with each of the modular units) may be in thermal communication with one or more heat sources. In some cases, a first modular unit of the plurality of modular units may be in thermal communication with a first heat source and a second modular unit of the plurality of modular units may be in thermal communication with a second heat source. The first heat source may be the same as the second heat source. Alternatively, the first heat source may be different from the second heat source (e.g., the first heat source may generate thermal energy by combustion and the second heat source may generate thermal energy by resistive or Joule heating). In some cases, the first modular unit and the second modular unit of the plurality of modular units may be in thermal communication with the same heat source. In other cases, the first modular unit and the second modular unit of the plurality of modular units may be in thermal communication with different heat sources.

In some embodiments, multiple modular units can be stacked to adjust the amount of hydrogen made in parallel. In some cases, multiple modular units may be positioned such that the edges of the modular units are flush with one another. In other cases, the position and/or orientation of the modular units can be adjusted with respect to one another to achieve a desired spatial arrangement or shape for installation within a target volume.

In some cases, the first reactor module may be in fluid communication with the second reactor module. Such fluid communication may allow ammonia or other gases (e.g., hydrogen and/or nitrogen) to flow between the first reactor module and the second reactor module. In some cases, hydrogen produced using the first reactor module may be combusted to heat or partially heat the second reactor module or one or more components of the second reactor module (e.g., the catalyst of the second reactor module). In some cases, hydrogen produced using the first reactor module may be directed or redirected to one or more fuel cells to power the fuel cells. The fuel cells may generate electricity using the hydrogen produced using the first reactor module and/or the second reactor module.

In some embodiments, the first reactor module can have a start-up time of up to about 5 minutes to reach a target temperature of at least about 550 degrees Celsius. In some embodiments, the first reactor module can have a start-up time of up to about 60 minutes to reach a target temperature of at least about 550 degrees Celsius. The first reactor module can provide an ammonia conversion efficiency of at least about 90%. In some cases, the first reactor module can have a power density of about 10 watts of power per cubic centimeter of reactor bed volume.

In some cases, at least one of the first reactor module and the second reactor module can be configured for self-heating via electricity or hydrogen combustion (i.e., autothermal reforming). In some cases, the first reactor module and/or the second reactor module may be configured to combust hydrogen produced by the first and second reactor modules, respectively, to generate additional thermal energy. Such additional thermal energy may be used to heat a catalyst in the first reactor module and/or the second reactor module.

In some embodiments, the system may further include one or more fuel cells in fluid communication with at least one of the first reactor module and the second reactor module. The one or more fuel cells may be configured to receive hydrogen produced using the first reactor module and/or the second reactor module and to use the hydrogen to produce electrical energy.

In some cases, the system may further include a hybrid battery for load following and initial reactor heating power. The hybrid battery may be disposed in electrical communication with at least one of the first reactor module and the second reactor module. In some cases, the hybrid battery may be used to pass electrical current through the catalyst of the first reactor module and/or the second reactor module to enable resistive or joule heating. In some cases, the hybrid battery may be configured to adjust the amount of electrical current provided to the first reactor module and/or the second reactor module. In some cases, the hybrid battery may be configured to provide different electrical currents to the first reactor module and the second reactor module.

FIG. 64A illustrates a schematic of a system configuration for processing ammonia during start-up operation, according to one or more embodiments of the present disclosure. In some cases, the ammonia reactor/reformer (6405) may be heated with an input of electricity. In some cases, the stream produced by the ammonia reactor/reformer (6405) may be passed through a heat exchanger (6404) and fed to one or more combustors in the ammonia reactor/reformer (6405) as a combustion fuel. In some cases, the stream produced by the ammonia reactor/reformer (6405) may be passed through a heat exchanger (6404) and fed at least partially back to the ammonia reactor/reformer (6405). In some cases, an air-cooled heat exchanger (6403) may be used to vaporize the ammonia before it is fed to the heat exchanger (6404) and/or the ammonia reactor/reformer (6405). In some cases, one or more air supply units (6412) may supply air to one or more combustors in the ammonia reactor/reformer (6405) for the combustion reaction.

FIG. 64B illustrates a schematic of a system configuration for processing ammonia during steady-state or post-start-up operation according to one or more embodiments of the present disclosure. In some cases, the stream produced by the ammonia reactor/reformer (6405) may be passed through a heat exchanger (6404) and fed at least in part to (i) one or more adsorbers (6408 and 6409) and a fuel cell system (6410), and/or (ii) one or more combustors in the ammonia reactor/reformer (6405). In some cases, the stream produced by the ammonia reactor/reformer (6405) may be passed through a heat exchanger (6404) and fed at least in part back to the ammonia reactor/reformer (6405). In some cases, capturing heat from the stream produced by the ammonia reactor/reformer (6405) and feeding it back to the ammonia reactor/reformer (6405) can improve ammonia conversion efficiency. In some cases, passing the stream produced by the ammonia reactor/reformer (6405) through a heat exchanger (6404) can improve ammonia conversion efficiency if the heat exchanger is used to heat the ammonia input to the ammonia reactor/reformer (6405). In some cases, the stream produced by the ammonia reactor/reformer (6405) can pass through a heat exchanger (6404), one or more adsorber (6408 and 6409), and a fuel cell system (6410) and be supplied to one or more combustors in the ammonia reactor/reformer (6405) as combustion fuel. In some cases, one or more air supply units (6412) supply air to one or more combustors in the ammonia reactor/reformer (6405) for the combustion reaction. In some cases, the stream produced by the ammonia reactor/reformer (6405) may pass through a heat exchanger (6404) after which the stream may be fed to one or more combustors in the ammonia reactor/reformer (6405) as combustion fuel. In some cases, the fuel cell system (6410) may consume hydrogen and produce useful electricity. In some cases, at least a portion of the ammonia reactor/reformer (6405) may be heated with an input of electricity. In some cases, the ammonia reactor/reformer (6405) may not be electrically heated. In some cases, the adsorber or adsorber may include a temperature sensor attached thereto, which may indicate and/or monitor the quality or capacity of the adsorber over time. Pressure sensor (P), temperature sensor (T), ammonia sensor (A), liquid fuel storage tank (6401), liquid fuel supply unit (6402) (e.g., valves, pumps, mass flow controllers, etc.), optional air cooling/heating heat exchanger (6403) (which may be connected to the fuel cell heat dissipation unit and/or the surroundings to evaporate the liquid fuel), heat exchanger (6404) (e.g., gas to gas, liquid to gas, liquid/gas two-phase to gas heat exchanger), and an Shown are a monia reactor/reformer (6405), an optional mass flow controller or mass flow meter (6406), a flow control unit (6407) (e.g., a 3-way valve, a valve, a back pressure regulator, etc.), an adsorber (6408), an optional adsorber (6409), a fuel cell system (6410), a gas supply unit (6411) (e.g., a valve, a mass flow controller, a check valve, etc.), and an air supply unit (6412) (e.g., a fan, a blower, a compressor, etc.).

In some cases, the system may further include a selective catalytic reduction (SCR) system (e.g., an SCR catalyst) for removing nitrous oxides ( _NOx ) from the one or more combustion exhaust streams. In some cases, the SCR system may receive ammonia from one or more ammonia tanks (e.g., for use as a reductant to reduce _NOx ). In some cases, the SCR system may receive urea from one or more urea tanks. In some cases, the SCR system may receive a mixture of urea and water from one or more urea and water mixture tanks. In some cases, the SCR system may receive urea and water from one or more urea tanks and one or more water tanks.

FIG. 65 illustrates a schematic of a system configuration for processing ammonia during start-up operation, according to one or more embodiments of the present disclosure. In some cases, the ammonia reactor/reformer (6505) is heated with an input of electricity. In some cases, the stream produced by the ammonia reactor/reformer (6505) can be passed through a heat exchanger (6504) and at least one adsorber (6507) and fed to one or more combustors in the ammonia reactor/reformer (6505) as a combustion fuel. In some cases, the stream produced by the ammonia reactor/reformer (6505) can be passed through a heat exchanger (6504) and fed at least partially back to the ammonia reactor/reformer (6505). In some cases, an air-cooled heat exchanger (6503) can be used to vaporize the ammonia before it is fed to the heat exchanger (6504) and/or the ammonia reactor/reformer (6505). In some cases, one or more air supply units (6512) may supply air to one or more combustors in the ammonia reactor/reformer (6505) for the combustion reaction. Pressure sensor (P), temperature sensor (T), ammonia sensor (A), liquid fuel storage tank (6501), liquid fuel supply unit (6502) (e.g., valves, pumps, mass flow controllers, etc.), optional air cooling/heating heat exchanger (6503) (connected to fuel cell heat dissipation unit and/or ambient to evaporate liquid fuel), heat exchanger (6504) (e.g., gas to gas, liquid to gas, liquid/gas two-phase flow to gas heat exchanger), ammonia reactor/reformer (6505), optional mass flow controller or mass flow meter (6506), adsorber (6507), flow regulation unit (6508) (e.g., 3-way valve, valve, back pressure regulator, etc.), optional adsorber (6509), fuel cell system (6510), gas supply unit (6511) (e.g., valves, mass flow controllers, check valves, etc.), and air supply unit (6512) (e.g., fan, blower, compressor, etc.).

FIG. 66 illustrates a schematic of a system configuration for processing ammonia during steady-state or post-start-up operation according to one or more embodiments of the present disclosure. In some cases, the stream produced by the ammonia reactor/reformer (6605) may be passed through a heat exchanger (6604) and at least partially fed to (i) one or more adsorbers (6607 and 6609) and then (ii) one or more combustors in the fuel cell system (6610) and/or the ammonia reactor/reformer (6605). In some cases, the stream produced by the ammonia reactor/reformer (6605) may be passed through a heat exchanger (6604) and at least partially fed back to the ammonia reactor/reformer (6605). In some cases, capturing heat from the stream produced by the ammonia reactor/reformer (6605) and feeding it back to the ammonia reactor/reformer (6605) can improve ammonia conversion efficiency. In some cases, passing the stream produced by the ammonia reactor/reformer (6605) through a heat exchanger (6604) can improve ammonia conversion efficiency if a heat exchanger is used to heat the ammonia input to the ammonia reactor/reformer (6605). In some cases, the stream produced by the ammonia reactor/reformer (6605) may be fed to one or more combustors in the ammonia reactor/reformer (6605) as a combustion fuel. In some cases, the stream produced by the ammonia reactor/reformer (6605) may pass through a heat exchanger (6604), one or more adsorber (6607 and 6609), and a fuel cell system (6610) and be fed to one or more combustors in the ammonia reactor/reformer (6605) as a combustion fuel. In some cases, one or more air supply units (6612) may feed air to one or more combustors in the ammonia reactor/reformer (6605) for the combustion reaction. In some cases, the fuel cell system (6610) can consume hydrogen and produce useful electricity. In some cases, at least a portion of the ammonia reactor/reformer (6605) may be heated with an input of electricity. In some cases, the ammonia reactor/reformer (6605) may not be electrically heated. Pressure sensor (P), temperature sensor (T), ammonia sensor (A), liquid fuel storage tank (6601), liquid fuel supply unit (6602) (e.g., valves, pumps, mass flow controllers, etc.), optional air cooling/heating heat exchanger (6603) (connected to fuel cell heat sink unit and/or ambient to evaporate liquid fuel), heat exchanger (6604) (e.g., gas to gas, liquid to gas, liquid/gas two-phase flow to gas heat exchanger), ammonia reactor/reformer (6605), optional mass flow controller or mass flow meter (6606), adsorber (6607), flow regulation unit (6608) (e.g., 3-way valve, valve, back pressure regulator, etc.), optional adsorber (6609), fuel cell system (6610), gas supply unit (6611) (e.g., valves, mass flow controllers, check valves, etc.), and air supply unit (6612) (e.g., fan, blower, compressor, etc.).

FIG. 67 illustrates a schematic of an example of a system reactor and/or hot box configuration according to one or more embodiments of the present disclosure. One or more combustion reactors and one or more electric reactors may be configured for ammonia reforming. In some cases, the ammonia stream (6701) may pass through a conduit concentric with the combustion reactor such that the ammonia stream (6701) is preheated by heat from the combustion reactor. In the configuration illustrated in FIG. 67, the ammonia stream (6701) may flow parallel (e.g., along the same direction) to the reactants and products of the combustion reaction, and heat is transferred (from the reactants and products of the combustion reaction) across the walls of the conduit to the ammonia stream (6701). In some cases, the preheated ammonia (6702) may enter the electric reactor for ammonia reforming. And in some cases, an outlet stream (6703) (e.g., comprising 50% or more _H2 / _N2 and 50% or less _NH3 by mole fraction) may exit the electric reactor and enter the combustion reactor for further ammonia reforming. In some cases, the outlet stream (6704) (e.g., containing 98% or more _H2 / _N2 and 2% or less _NH3 by mole fraction) can leave the combustion reactor and enter a heat exchanger to heat the ammonia stream (6701) that is fed to the combustion reactor and the electric reactor. In some cases, the outlet stream (6703) from the electric reactor can enter a combustion reactor adjacent to a region of the combustion reactor such that the outlet stream (6703) is further reformed in the combustion reactor adjacent the region. In some cases, the region of the combustion reactor can include a relatively low thermal gradient between the ammonia and the combustion gases (compared to another region of the combustion reactor). In some cases, the region of the combustion reactor can include a relatively small amount of combustion gases to be combusted to generate heat compared to another region of the combustion reactor. Shown are an electric reactor ("E reactor"), an electric heater (E_1) at least partially embedded in the electric reactor, a combustion reactor ("C reactor"), a combustion heater (C_1) at least partially embedded in the combustion reactor, ammonia in preheating through the combustor 6701, preheated ammonia out combustor/E reactor in (6702), E reactor out/C reactor in (6703), C reactor out (6704), combustion fuel including hydrogen (6705), air in (6706), and flue gas (6707), one or more catalysts in the electric reactor, and one or more catalysts in the combustion reactor. The one or more catalysts in the electric reactor may be the same or different than the one or more catalysts in the combustion reactor. The location of the inlet and outlet ports of the reactors in the flow diagram may be changed for various designs. In some cases, both the inlet and outlet ports may be located in similar positions on the reactor along the length or in opposite positions on the reactor.

FIG. 68 illustrates a schematic of an example of a system reactor and/or hot box configuration according to one or more embodiments of the present disclosure. In some cases, the combustion reactor(s) and the electric reactor(s) may be configured for ammonia reforming. In some cases, the ammonia stream (6801) may pass through a conduit concentric with the combustion reactor such that the ammonia stream (6801) is preheated using thermal energy from the combustion reactor. In the configuration illustrated in FIG. 68, the ammonia stream (6801) may flow counter to (e.g., in the opposite direction) the reactants and products of the combustion reaction, and heat may be transferred (from the reactants and products of the combustion reaction) across the walls of the conduit to the ammonia stream (6801). In some cases, the preheated ammonia (6802) may enter the electric reactor for ammonia reforming. And in some cases, an outlet stream (6803) (e.g., comprising 50% or more _H2 / _N2 and 50% or less _NH3 by mole fraction) may exit the electric reactor and enter the combustion reactor for further ammonia reforming. And optionally, the outlet stream (6804) (e.g., containing 98% or more _H2 / _N2 and ₂ % or less NH3 by mole fraction) leaves the combustion reactor and enters a heat exchanger to heat the ammonia stream (6801) that is fed to the combustion reactor and the electric reactor. In some cases, the ammonia can be heated in turn by the combustion reactor and the electric reactor, and then flow through a heat exchanger to heat the ammonia stream (6801) that is fed to the combustion reactor and the electric reactor. In some cases, the outlet stream (6803) from the electric reactor can flow through a region adjacent to the combustion reactor and be further reformed in the combustion reactor. In some cases, the ammonia exhaust from the electric reactor can flow through an inlet portion of the combustion reactor (near 6803) and exit at a point away from the inlet portion (near 6804). Shown are an electric reactor ("E reactor"), an electric heater (E_1) at least partially embedded in the electric reactor, a combustion reactor ("C reactor", (C_1)), a combustion heater (C_1) at least partially embedded in the combustion reactor, ammonia in preheating through combustor (6801), ammonia out preheating through combustor/E reactor in (6802), E reactor out/C reactor in (6803), C reactor out (6804), combustion fuel including hydrogen (6805), air in (6806), combustion exhaust gas (6807), one or more catalysts in the electric reactor, and one or more catalysts in the combustion reactor. The one or more catalysts in the electric reactor may be the same or different than the one or more catalysts in the combustion reactor. The location of the inlet and outlet ports of the reactors in the flow diagram may be changed for various designs. In some cases, both the inlet and outlet ports may be located in similar positions on the reactor along the length or in opposite positions on the reactor.

FIG. 69 illustrates a schematic of an example of a system reactor and/or hot box configuration according to one or more embodiments of the present disclosure. One or more combustion reactors and one or more electric reactors may be configured for ammonia reforming. In some cases, the ammonia stream (6901) may pass through a conduit concentric with the combustion reactor such that the ammonia stream (6901) is preheated using thermal energy from the combustion reactor. In the configuration illustrated in FIG. 69, the ammonia stream (6901) may flow counter to (e.g., in the opposite direction) the reactants and products of the combustion reaction, and heat may be transferred (from the reactants and products of the combustion reaction) across the walls of the conduit to the ammonia stream (6901). In some cases, the preheated ammonia (6902) enters the combustion reactor for ammonia reforming. And in some cases, an outlet stream (6903) (e.g., comprising 50% or more _H2 / _N2 and 50% or less _NH3 by mole fraction) may exit the combustion reactor and enter the electric reactor for further ammonia reforming. And optionally, the outlet stream (6904) (e.g., containing 98% or more _H2 / _N2 and 2% or less _NH3 by mole fraction) leaves the electric reactor and enters a heat exchanger to heat the ammonia stream (6901) that is fed to the combustion reactor and the electric reactor. In some cases, the ammonia exhaust from the combustion reactor can be recycled (6902) to a portion of the combustion reactor that is relatively cooler compared to another portion of the combustion reactor to heat the relatively cooler portion. In some cases, the relatively cooler portion can be near where the ammonia first comes into contact with the combustion reactor combustion gases. In some cases, the ammonia exhaust from the combustion reactor after being recycled through the combustion reactor (6903) can be further heated by the electric reactor before being fed to the heat exchanger. Shown are an electric reactor (E reactor), an electric heater (E_1) at least partially embedded in the electric reactor, a combustion reactor (C reactor), a combustion heater (C_1) at least partially embedded in the combustion reactor, ammonia in preheating through combustor (6901), ammonia out preheating through combustor/C reactor in (6902), C reactor out/E reactor in (6903), E reactor out (6904), combustion fuel including hydrogen (6905), air in (6906), combustion exhaust gas (6907), one or more catalysts in the electric reactor, and one or more catalysts in the combustion reactor. The one or more catalysts in the electric reactor may be the same or different from the one or more catalysts in the combustion reactor. The location of the inlet and outlet ports of the reactors in the flow diagram may be changed for various designs. In some cases, both the inlet and outlet ports may be located in a similar position on the reactor along the length or in opposite positions on the reactor.

Figure 70 illustrates a schematic of an example of a system reactor and/or hot box configuration during start-up operation, according to one or more embodiments of the present disclosure. In some cases, exhaust streams containing hydrogen and/or nitrogen from the combustion reactor, the electric reactor, or both may flow through a heat exchanger and be used as combustion fuel in the combustion reactor. Liquid, liquid/gas two-phase, or gaseous ammonia (7001) is shown. Ammonia gas (7002), product gas containing hydrogen, nitrogen, and ammonia (7003), cooled product gas (7004), combustion fuel gas containing hydrogen and nitrogen (7005), air (7006), flue gas (7007), and electricity (7008) to the C/E reactor module are shown.

Figure 71 illustrates a schematic of an example of a system reactor and/or hot box configuration during start-up according to one or more embodiments of the present disclosure. In some cases, the exhaust stream containing hydrogen and/or nitrogen from the combustion reactor, the electric reactor, or both can flow through a heat exchanger and then an adsorber to be used as a combustion fuel in the combustion reactor. In the example shown in Figure 71, the adsorber can remove trace amounts of ammonia (e.g., 10,000 ppm by volume) from the exhaust stream (7104) to improve the combustion characteristics of the filtered stream (7105) input into the C-/E-reactor module (7108). Liquid, liquid/gas two-phase, or gaseous ammonia (7101), ammonia gas (7102), product gas containing hydrogen, nitrogen, and ammonia (7103), cooled product gas (7104), filtered combustion fuel gas containing hydrogen and nitrogen (7105), air (7106), flue gas (7107), and electricity (7108) to the C/E reactor module are shown.

FIG. 72 illustrates a schematic of an example of a system reactor and/or hot box configuration during steady-state or post-startup operation according to one or more embodiments of the present disclosure. In some cases, the exhaust stream (7203) containing hydrogen and nitrogen from the combustion reactor, the electric reactor, or both may flow through a heat exchanger and then an adsorber. The fuel cell exhaust stream (7206) (containing hydrogen and/or nitrogen not used by the fuel cell) may be used as a combustion fuel for the combustion reactor. In some cases, the fuel cell exhaust stream (7206) may include about 10-40% of the hydrogen from the exhaust stream (7203) from the combustion reactor, the electric reactor, or both. In some cases, the fuel cell exhaust stream (7206) may include about 5-50% of the hydrogen from the exhaust stream (7203) from the combustion reactor, the electric reactor, or both. In some cases, the fuel cell exhaust stream (7206) may contain about 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100% of the hydrogen from the exhaust stream (7203) from the combustion reactor, the electric reactor, or both. Shown are liquid, liquid/gas two-phase, or gaseous ammonia (7201), ammonia gas (7202), product gas (7203) containing hydrogen, nitrogen, and ammonia, cooled product gas (7204), filtered product gas (7205), combustion fuel gas (7206) containing unconverted hydrogen and nitrogen from the fuel cell, air (7207), flue gas (7208), optional electricity (7209) to the C/E reactor module, and electrical output (7210) from the fuel cell.

FIG. 73 illustrates an example of a system reactor and/or hot box configuration during steady-state or post-startup operation according to one or more embodiments of the present disclosure. In some cases, the exhaust stream (7303) containing hydrogen and nitrogen from the combustion reactor, the electric reactor, or both may flow through a heat exchanger, then an adsorber, and then a hydrogen separation unit (e.g., a pressure swing adsorption [PSA] system or a membrane separation system). In some cases, the product stream (7306) from the hydrogen separation unit containing purified hydrogen can be input to a fuel cell. In some cases, the outlet or exhaust stream (7307) from the hydrogen separation unit containing hydrogen and nitrogen may be used as a combustion fuel for the combustion reactor. In some cases, the outlet or exhaust stream (7307) of the hydrogen separation unit may contain about 10-40% of the hydrogen from the exhaust stream (7303) from the combustion reactor, the electric reactor, or both. In some cases, the outlet or exhaust stream (7307) of the hydrogen separation unit may comprise about 5-50% of the hydrogen from the exhaust stream (7303) from the combustion reactor, the electric reactor, or both. In some cases, the outlet or exhaust stream (7307) of the hydrogen separation unit may comprise about 0, 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100% of the hydrogen from the exhaust stream (7303) from the combustion reactor, the electric reactor, or both. Shown are liquid, liquid/gas two-phase, or gaseous ammonia (7301), ammonia gas (7302), product gas containing hydrogen, nitrogen, and ammonia (7303), cooled product gas (7304), filtered product gas (7305), filtered product gas containing primarily hydrogen (7306), hydrogen separation unit effluent stream containing hydrogen and nitrogen (7307), air (7308), flue gas (7309), optional electricity to the combustor/electrical reactor module (7310), and electrical output from the fuel cell (7311).

83 illustrates a flow diagram of a start-up method according to one or more embodiments of the present disclosure. In some cases, the start-up method may include (1) heating the electric reactor to an electric reactor target temperature, (2) feeding ammonia to the electric reactor and reforming the ammonia in the electric reactor, (3) combusting at least a portion of the electric reactor outlet stream with air to heat the combustion reactor, (4) shutting down the electric reactor, if necessary, and/or (5) increasing the ammonia flow rate to at least a predetermined rate. In some cases, steps (1) and (2) may be performed in sequence or in parallel. In some cases, at least two steps in steps (1)-(5) may be performed in sequence or in parallel. Once state (5) is reached and self-sustaining autothermal reforming is maintained (i.e., steady-state condition), the ammonia flow rate may be further increased above a predetermined rate while maintaining autothermal reforming, depending on the operating requirements (e.g., fuel cell output power, reactor temperature, combustor temperature, reactor pressure, ammonia flow rate, etc.). Step (4) may or may not be performed depending on the combustion reactor temperature and ammonia conversion efficiency. An electric reactor may be used to balance the temperature distribution. In some cases, if the efficiency of the fuel cell is high, electricity can also be used as the main source of heating power.

84 illustrates a flow diagram of a start-up method according to one or more embodiments of the present disclosure. In some cases, the start-up method includes: (1) heating the electric reactor to at least an electric reactor target temperature; (2) dosing the electric reactor with ammonia having at least an initial target flow rate; (3) dosing at least a small portion of (i) air and (ii) the outlet flow from the electric reactor to the combustion reactor; (4) igniting the combustion reactor and adjusting the flow rate of air into the combustion reactor; (5) heating the combustion reactor to at least a first target combustion reactor temperature; (6) shutting down the electric reactor; and (7) using a controller, incrementally increasing the ammonia flow rate to at least a second target flow rate and simultaneously controlling and increasing the air flow rate of the combustion reactor to maintain at least the second target combustion reactor temperature. In some cases, the second target combustion reactor temperature may be the same as or different from the first target combustion reactor temperature, (8) inputting at least a portion of the outlet stream from the combustion reactor into a fuel cell, (9) reacting the outlet stream from the combustion reactor to generate power in the fuel cell, (10) inputting at least a portion of the outlet stream from the fuel cell into the combustion reactor, (11) adjusting the combustion reactor air flow rate to maintain at least a third target combustion reactor temperature. In some cases, the third target combustion reactor temperature may be the same as or different from the first target combustion reactor temperature or the second target combustion reactor temperature, and (12) adjusting the ammonia flow rate to at least a third target flow rate (e.g., by tweaking or decreasing/increasing the ammonia flow rate) and/or adjusting the combustion reactor air flow rate to maintain at least a fourth target combustion reactor temperature. In some cases, the fourth target combustion reactor temperature may be the same or different from the first target combustion reactor temperature, the second target combustion reactor temperature, or the third target combustion reactor temperature; and/or (13) achieving a predetermined initial operating condition (i.e., a steady-state condition). In some cases, at least two steps in steps (1)-(13) may be performed in sequence or in parallel. In some cases, the start-up process may be performed without steps (1), (2), (3), (4), (5), (6), (7), (8), (9), (10), (11), (12), or a combination thereof. The combustion reactor effluent stream may be passed through an adsorber and a heat exchanger to remove unconverted ammonia and to cool and/or recover heat before entering the fuel cell. Step (6) may be performed anywhere in the flow chart as long as the combustion reactor temperature is above a predetermined threshold temperature. Step (6) may not be performed if the combustion reactor temperature is below a predetermined threshold temperature. Step (9) may be performed anywhere after step (8).

FIG. 85 illustrates a flow diagram of a start-up method according to one or more embodiments of the present disclosure. In some cases, the start-up method includes: (1) heating the electric reactor to at least a target temperature of the electric reactor; (2) inputting ammonia having at least an initial target flow rate into the electric reactor; (3) inputting an outlet flow from the electric reactor to a fuel cell; (4) inputting (i) air and (ii) an outlet flow from the fuel cell to a combustion reactor to ignite the outlet flow and air in the combustion reactor; (5) reacting hydrogen in the electric reactor and/or the outlet flow from the combustion reactor to generate power from the fuel cell; (6) heating the combustion reactor to at least a first combustion reactor target temperature; (7) shutting down the electric reactor; and (8) incrementally increasing the ammonia flow rate to at least a second target flow rate using a controller while controlling (e.g., increasing) the air flow rate to maintain at least a second target combustion reactor temperature. In some cases, the second target combustion reactor temperature may be the same as or different from the first target combustion reactor temperature; (9) adjusting the air flow rate to maintain at least a third target combustion reactor temperature. In some cases, the third target combustion reactor temperature may be the same as or different from the first target combustion reactor temperature or the second target combustion reactor temperature; (10) adjusting the ammonia flow rate (e.g., by tweaking or decreasing/increasing the ammonia flow rate) to at least the second target flow rate and adjusting the air flow rate to the combustion reactor to maintain at least a fourth combustion reactor temperature. In some cases, the fourth target combustion reactor temperature may be the same as or different from the first target combustion reactor temperature, the second target combustion reactor temperature, or the third target combustion reactor temperature; and/or (13) achieving the predetermined initial operating condition. In some cases, at least two steps in steps (1)-(13) may be performed sequentially or in parallel. In some cases, the start-up process may be performed without steps (1), (2), (3), (4), (5), (6), (7), (8), (9), (10), (11), (12), or combinations thereof. The reactor outlet stream may be passed through an adsorber and a heat exchanger to remove unconverted ammonia and to cool and/or recover heat before entering the fuel cell. Step (7) may be performed anywhere in the flow chart as long as the C reactor temperature is above a predetermined threshold temperature. Step (7) may not be performed if the C reactor temperature is below a predetermined threshold temperature. Step (5) may be performed anywhere after step (3).

86 illustrates a flow diagram of a start-up method according to one or more embodiments of the present disclosure. In some cases, the start-up method includes: (1) heating the electric reactor to a target temperature of the electric reactor; (2) dosing the electric reactor with ammonia having at least an initial target flow rate; (3) dosing at least a small portion of the outlet flow from the electric reactor to the combustion reactor; (4) dosing air into the combustion reactor using an air supply unit and igniting the outlet flow from the electric reactor and the air in the combustion reactor; (5) heating the combustion reactor to a first target combustion reactor temperature; (6) using a controller to incrementally increase the ammonia flow rate to at least a second target flow rate while simultaneously controlling (e.g., increasing) the flow rate of air into the combustion reactor to maintain at least the second target combustion reactor temperature. In some cases, the second target combustion reactor temperature may be the same or different from the first target combustion reactor temperature; and (7) achieving a predetermined initial operating condition. In some cases, at least two steps in steps (1)-(6) may be performed in sequence or in parallel. In some cases, the start-up process may be performed without steps (1), (2), (3), (4), (5), (6), or combinations thereof. The reactor outlet stream may be passed through an adsorber and a heat exchanger to remove unconverted ammonia and to cool and/or recover heat before entering the fuel cell. If the C reactor temperature exceeds a predetermined threshold temperature, the E reactor may be shut down.

It is noted herein that any of the steps or processes described with respect to Figures 83-86 may be combined with other of the steps or processes described with respect to Figures 83-86, and the examples described with respect to Figures 83-86 should not be construed as limiting this disclosure.

FIG. 87 illustrates a flow diagram of a post-start-up operation method according to one or more embodiments of the present disclosure. For a given set of system operating parameters, the self-sustaining autothermal operating conditions can be pre-determined (e.g., minimum/maximum _NH3 flow rate, corresponding FC power and hydrogen consumption rate, minimum/maximum state of charge [SOC] of the cell, minimum/maximum air flow rate, etc.). In some aspects, the present disclosure provides a method for maintaining and/or adjusting operating parameters of a system comprising a fuel cell to maintain and/or adjust the power output of the fuel cell. In some cases, the method can include monitoring the power output of the fuel cell and automatically adjusting (increasing or decreasing) the power output (e.g., by monitoring an electrical load coupled to the fuel cell). In some cases, the method can adjust various operating parameters (8703), including, but not limited to, the combustion reactor air flow rate, the ammonia flow rate to the system or any component thereof (e.g., the combustion reactor, the electric heater, etc.), and/or the hydrogen utilization rate of the fuel cell. A "*" indicates an adjustable condition, including the combustor air flow rate, the ammonia ( _NH3 ) flow rate, the fuel cell (FC) _H2 utilization rate, or the E-reactor power. "a" indicates a predetermined achievable fuel cell (FC) hydrogen utilization or consumption rate from the FC input stream to maintain self-sustaining autothermal reforming for a given FC inlet flow rate. "b" indicates a predetermined maximum _NH3 flow rate. "c" indicates a predetermined minimum _NH3 flow rate. The incremental or decremental change in _NH3 flow rate can be based on a predetermined value and/or percentage of the current value. In some cases, the controller can control _NH3 flow rate, control air flow rate, control flow pressure, control valves, control FC power output, control cell power output, control E-reactor power input, or any combination thereof. In some cases, the sensors can measure temperature, pressure, fuel cell power output, cell power output, cell SOC, fuel cell hydrogen consumption, and _NH3 conversion efficiency.

Optionally, the method may include increasing the power output of the fuel cell (8701). Optionally, the method may include comparing the hydrogen utilization of the fuel cell to a predetermined threshold. Optionally, the method may include increasing the power output of the fuel cell by increasing the hydrogen utilization and/or consumption (while still maintaining the hydrogen utilization at a level below the predetermined threshold) if the hydrogen utilization of the fuel cell is lower than the predetermined threshold. Optionally, the method may include comparing the ammonia flow rate into the system to a predetermined ammonia flow rate value if the hydrogen utilization of the fuel cell is equal to or greater than the predetermined threshold. Optionally, the predetermined ammonia flow rate value may be a maximum ammonia flow rate value for the system. Optionally, the method may include increasing the ammonia flow rate if the ammonia flow rate into the system is less than the predetermined ammonia flow rate value. Optionally, the method may include maintaining the ammonia flow rate if the ammonia flow rate into the system is greater than the predetermined ammonia flow rate value. Optionally, the method may include increasing the power output of the fuel cell if the ammonia flow rate into the system is greater than the predetermined ammonia flow rate value.

In some cases, the method may include decreasing the power output of the fuel cell (8702). In some cases, the method may include comparing the ammonia flow rate into the system to a predetermined ammonia flow rate value. In some cases, the predetermined ammonia flow rate value may be a minimum ammonia flow rate value for the system. In some cases, the method may include decreasing the ammonia flow rate if the ammonia flow rate into the system is greater than the predetermined ammonia flow rate value. In some cases, the method may include maintaining the ammonia flow rate if the ammonia flow rate into the system falls below the predetermined ammonia flow rate value. In some cases, the method may include decreasing the power output of the fuel cell if the ammonia flow rate into the system falls below the predetermined ammonia flow rate value.

In some cases, the method can include a shutdown process. In some cases, the shutdown process can include reducing any one or combination of the ammonia flow rate, the air flow rate, and the fuel cell power to zero.

In some cases, the method may include a fault detection system. In some cases, the fault detection system may detect a fault. In some cases, the fault may be classified as a major fault or a minor fault. Examples of major faults include a reactor vessel breaking or ammonia leaking above a predetermined leak level. Examples of minor faults include a reactor or heater temperature deviation (e.g., 10% or more) from a target temperature or an increase in ammonia concentration in one or more inlet streams to one or more adsorber or fuel cell systems above a predetermined threshold concentration. In some cases, if a major fault is detected by the fault detection system, a shutdown process may be initiated. In some cases, if a minor fault is detected by the fault detection system, a reactor in the system may operate in a standby state while maintaining a predetermined temperature. In some cases, if a minor fault is detected by the fault detection system, a fuel cell in the system may be shut down. In some cases, if the fuel cell power needs to be shut down intermittently, the event may be classified as a minor fault. In some cases, a hot standby state (e.g., no fuel cell output power) may be maintained until the shutdown process is performed. In some cases, the hot standby state (e.g., no fuel cell output power) can be maintained until the fuel cell power output is performed.

FIG. 88 illustrates a process flow diagram of a post-startup operation process according to one or more embodiments of the present disclosure. Based on a set of predetermined system operating parameters, the self-sustaining autothermal operating conditions can be pre-determined (e.g., min/max _NH3 flow rate, corresponding FC power and hydrogen consumption rate, cell min/max SOC, min/max air flow rate, etc.). In some aspects, the present disclosure provides a method for maintaining and/or adjusting operating parameters of a system including a fuel cell to maintain and/or adjust the power output of the fuel cell. In some cases, the method can include determining whether the power output of the fuel cell is greater than or less than the electrical energy or power demand. In some cases, the method can adjust various operating parameters (8803), including, but not limited to, the combustion reactor air flow rate, the ammonia flow rate to the system or any component thereof (e.g., the combustion reactor, the electric heater, etc.), and/or the hydrogen utilization rate of the fuel cell. A "*" indicates an adjustable condition, including the combustor air flow rate, the _NH3 flow rate, the fuel cell (FC) _H2 utilization rate, or the E reactor power. "a" indicates a predetermined achievable fuel cell hydrogen utilization or consumption rate from the FC inlet flow rate to maintain self-sustaining autothermal reforming for a given FC inlet flow rate. "b" indicates a predetermined maximum _NH3 flow rate. "c" indicates a predetermined minimum _NH3 flow rate. "d" indicates a predetermined maximum battery state of charge. "e" indicates a predetermined minimum battery state of charge. The incremental or decremental change in _NH3 flow rate is based on a predetermined value and/or percentage of the current value. In some cases, the controller can control _NH3 flow rate, control air flow rate, control flow pressure, control valves, control FC power output, control battery power output, control E reactor power input, or any combination thereof. In some cases, the sensors can measure temperature, pressure, fuel cell power output, battery power output, battery SOC, fuel cell hydrogen consumption, and _NH3 conversion efficiency.

In some cases, the method may include increasing the power output of the fuel cell (8801). In some cases, the method may include comparing the hydrogen utilization of the fuel cell to a predetermined threshold. In some cases, the method may include increasing the power output of the fuel cell by increasing the hydrogen utilization and/or consumption (while still maintaining the hydrogen utilization at a level below the predetermined threshold). In some cases, the method may include using the battery to supplement the power output from the fuel cell to meet the electrical energy or power demand. In some cases, the method may include comparing the ammonia flow rate into the system to a predetermined ammonia flow rate value. In some cases, the predetermined ammonia flow rate value may be a maximum ammonia flow rate value for the system. In some cases, the method may include increasing the ammonia flow rate. In some cases, the method may include maintaining the ammonia flow rate. In some cases, the method may include increasing the power output of the fuel cell. In some cases, the method may include limiting an electrical load associated with the electrical energy or power demand.

In some cases, the method may include decreasing (8802) the power output of the fuel cell. In some cases, the method may include determining if the battery has a state of charge (SOC) above a predetermined threshold. In some cases, the method may include comparing an ammonia flow rate into the system to a predetermined ammonia flow rate value. In some cases, the predetermined ammonia flow rate value may be a minimum ammonia flow rate value for the system. In some cases, the method may include decreasing the ammonia flow rate. In some cases, the method may include maintaining the ammonia flow rate. In some cases, the method may include charging the battery using electrical energy or power generated by the fuel cell. In some cases, the method may include determining if the battery is fully charged.

FIG. 82 illustrates a controller according to one or more embodiments of the present disclosure. In some cases, the controller can monitor and/or control various operating parameters. In some cases, the controller can monitor and/or control the flow rate of ammonia into the system, the flow rate of gas into the fuel cell, the flow rate of air into the combustor, any flows into or out of the system or system components disclosed herein, or any combination thereof. In some cases, the controller can monitor and/or control the temperature of the reactor (e.g., electric reactor or combustion reactor), the fuel cell, the heat exchanger, the flows between components of the system, any system components, or any combination thereof. In some cases, the controller can monitor and/or control one or more valves, one or more pumps, one or more fans, one or more blowers, one or more compressors, or any combination thereof to regulate the ammonia flow rate, the flow rate of gas into the fuel cell, the flow rate from the air supply unit, any flows into or out of the system or system components disclosed herein, or any combination thereof. In some cases, the controller can monitor and/or control the power output or input of one or more system components disclosed herein, such as one or more fuel cells, one or more heaters, or any combination thereof. In some cases, the controller can monitor and/or control the concentration of a substance in the environment or in the system, such as humidity, ammonia concentration, hydrogen, or any combination thereof, in the environment or in any system component disclosed herein or flows therebetween. In some cases, the controller can monitor and/or control the pressure of a system component, or any flows therebetween, such as the reactor, fuel cell, ammonia storage tank, and any flows therebetween. In some cases, the controller can be communicatively coupled to one or more optional monitors (i.e., sensors). In some cases, the controller can be communicatively coupled to one or more optional monitors in addition to the one preferred monitor and control device. In some cases, the controller can be communicatively coupled to two or more optional monitors.

Hybrid heating

Figure 14 illustrates a schematic of an example of a primary reactor with hybrid heating, according to one or more embodiments of the present disclosure. Such a hybrid heating design can improve heat transfer while minimizing reactor heat losses, reducing start-up time. The hybrid heating design can also reduce the weight and volume of the reactor, improving the thermal management characteristics of the system while providing an optimized heat source for ammonia conversion.

The hybrid heating design for the main reactor may include one or more heat sources. The heat sources may be, for example, heating units described elsewhere herein. The heat sources may include start-up heating and reforming units and/or one or more main heating units. In some cases, the one or more heat sources may include two or more heat sources or heating units. In some cases, the two or more heat sources may be the same. In other cases, the two or more heat sources may be different. For example, a first heat source may be configured for Joule heating and a second heat source may be configured for combustion heating. In some cases, the hybrid heating reactor may include a separator (e.g., a physical component or structure) disposed between the first heat source and the second heat source. The separator may or may not facilitate the transfer of thermal energy across the separator.

In one example, a primary reactor having a hybrid heating design can be configured to receive ammonia through an inlet. The ammonia can be directed through the primary reactor, which can include a catalytic material that is heated using two or more heat sources. The catalytic material can be heated directly or indirectly using a first heat source when the ammonia is directed through a first portion of the primary reactor. The catalytic material can be heated directly or indirectly using a second heat source when the ammonia is directed through a second portion of the primary reactor. By heating the catalytic material in the presence of ammonia, hydrogen and/or nitrogen can be produced. The hydrogen and/or nitrogen can then be directed toward an outlet, which can be in fluid communication with one or more hydrogen fuel cells. In some embodiments, the hydrogen and/or nitrogen can be directed toward an outlet, which can be in fluid communication with one or more combustion engines and/or combustors.

In some embodiments, the primary reactor with a hybrid heating design can be configured to burn residual hydrogen gas from a reactor (e.g., the primary reactor or fast start reactor) or from one or more fuel cells to heat ammonia and/or catalyst material. In some cases, the reactor walls or fluid flow passage walls may be designed to allow heat exchange across the reactor walls or between fluid streams. In some cases, the heat source or heating unit may include a powder material with a high heat transfer coefficient to improve heat transfer. In some cases, the heat exchanger may be incorporated into or integrated with one or more components of the primary reactor, which may result in a more compact and efficient primary reactor. Additionally, the primary reactor may include one or more walls having a thickness in the range of about 0.5 millimeters to about 1.2 millimeters, which may reduce thermal mass. In some embodiments, the primary reactor may include one or more walls having a thickness in the range of about 1 millimeter to about 30 millimeters, which may increase structural integrity. The primary reactor with a hybrid heating design can be configured to minimize heat loss while providing fast hydrogen extraction and fast load following.

Figure 15A shows a schematic of reactor thermal reforming efficiency, heat absorption rate, and hydrogen burn rate data for the disclosed system and method. Hybrid heating of the reactor can result in higher thermal reforming efficiency compared to other conventional reactors across a range of different ammonia flow rates. Additionally, the hybrid heating reactor system disclosed herein exhibits more favorable heat absorption rates compared to other conventional reactors. In some cases, integrating or incorporating a heat exchanger with the hybrid heating reactor may further improve the hydrogen burn rate of the hybrid heating reactor.

FIG. 15B shows additional data for reactor thermal reforming efficiency, endothermic/thermal ratio, and fuel cell power output (watts) as a function of ammonia flow rate for various heating powers ranging from 100 watts to 600 watts. As used herein, the thermal reforming efficiency of a reactor can correspond to the ratio of available chemical energy output (e.g., H ₂ ) to chemical energy (NH ₃ ) and thermal energy into the reactor. In some cases, when 300 watts, 400 watts, 500 watts, or 600 watts of heating power are provided to the reactor, the thermal reforming efficiency of the reactor can reach about 90% for ammonia flow rates ranging from about 10 liters/min to about 20 liters/min. As used herein, the endothermic rate can correspond to the amount of thermal energy absorbed by the reactor during an endothermic reaction relative to the total amount of heat or thermal energy into the system (i.e., the total amount of heat or thermal energy provided or supplied to the reactor or catalyst bed by one or more heating units). In some cases, the heat absorption rate can reach about 0.5 for an ammonia flow rate ranging from about 10 liters/minute to about 20 liters/minute when 300 watts, 400 watts, 500 watts, or 600 watts of heating power are provided to the reactor. The power output of one or more fuel cells described herein can reach about 2 kilowatts (kW) for an ammonia flow rate ranging from about 15 liters/minute to about 20 liters/minute when 600 watts of heating power are provided to the reactor.

FIG. 16 illustrates schematic hybrid heating simulation data of the disclosed systems and methods. As described elsewhere herein, the hybrid heating reactor may include two or more heaters configured for different heating modes (e.g., combustion or joule electric heating). The hybrid heating reactor may exhibit a heating power ratio (R) ranging from 0 to 1. A heating power ratio of 0 indicates that all power is supplied to the first heater of the hybrid heating reactor, and a power ratio of 1 indicates that all power is supplied to the second heater of the hybrid heating reactor. A power ratio of 0.5 indicates that power is supplied equally to the first heater and the second heater. The heating power ratio (R) of the reactor may be determined as follows:
P_Heater_1 = P_Total*(R)
P_heater_2 = P_total*(1-R)

The hybrid heating data shown in Figure 16 was generated based on a total heating power (P_total) of thermal energy of 315 watts and an ammonia mass flow rate of 0.1 grams/second. The hybrid heating data shows significantly different heat utilization rates at different heating power ratios.

FIG. 17 illustrates schematic heating power ratio simulation data for the disclosed systems and methods. Due to differences in heat utilization, ammonia conversion efficiency can vary based on heating power ratio. Heating power ratio may be expressed as the ratio between combustion and Joule heating. As heating power ratio increases, ammonia conversion efficiency can also increase (e.g., linearly and/or proportionally).

In another aspect, the present disclosure provides a system comprising a reactor module configured to receive a source material including ammonia. The reactor module may comprise a catalyst and a plurality of heating units for heating the catalyst. In some embodiments, the plurality of heating units may comprise a first heating unit configured to heat at least a first portion of the catalyst by burning hydrogen, and a second heating unit configured to heat at least a second portion of the catalyst using electrical heating. As used herein, the term "electrical heating" generally refers to heating that is performed at least in part by passing electrons through a material (e.g., a conduit). The conduit may be a resistive load. In some examples, electrical heating may include Joule heating (i.e., heating that follows Ohm's law). Joule heating, also known as resistive heating, resistance heating, or ohmic heating, may include passing an electric current through a material (e.g., an electrical resistor, a catalyst, a catalytic material, or a catalytic bed) to create heat or thermal energy. In some cases, the catalyst may be used to produce hydrogen from a source material including ammonia when the catalyst is heated using a plurality of heating units. In some embodiments, the first portion and the second portion may be the same portion of the catalyst. In another embodiment, the first portion and the second portion may be different portions of the catalyst. In some cases, the first portion and the second portion may overlap or partially overlap.

In some cases, the first heating unit of the reactor module may be configured to heat the first portion of the catalyst based on combustion of hydrogen gas produced using the second reactor module. In some cases, the first heating unit may be configured to heat the first portion of the catalyst based on combustion of residual hydrogen gas from (i) one or more fuel cells in fluid communication with the reactor module, or (ii) the second reactor module (e.g., a fast start reactor module described elsewhere herein). In some cases, the second heating unit may be configured to heat the second portion of the catalyst by passing an electric current through the second portion of the catalyst. In some cases, the first portion of the catalyst and the second portion of the catalyst may be contiguous (i.e., physically connected). In other cases, the first portion of the catalyst and the second portion of the catalyst may be separated by a third portion of the catalyst. The third portion of the catalyst may be disposed between the first and second portions of the catalyst. In some cases, the first and second portions of the catalyst may be in thermal communication with each other (directly or indirectly through the third portion of the catalyst). In other cases, the first and second portions of the catalyst may not or need not be in thermal communication with each other.

In some embodiments, the system may further include a second reactor module in fluid and/or thermal communication with the reactor module. The second reactor module may include a second catalyst and a second heating unit. The second heating unit may be configured to heat the second catalyst. In some cases, the second heating unit may include one or more electrodes for passing an electric current through the second catalyst to heat the second catalyst. When the second catalyst is heated using the second heating unit, the second catalyst can be used to produce hydrogen from ammonia.

In some embodiments, the heat load distribution between the first heating unit and the second heating unit of the primary reactor may be adjustable to increase the ammonia conversion efficiency and/or improve the thermal efficiency of the reactor module. The heat load distribution may include a heating power ratio corresponding to a ratio between the heating power of the first heating unit and the heating power of the second heating unit. The heating power of the first heating unit and the second heating unit may be adjusted to achieve a desired ammonia conversion efficiency and thermal efficiency. In some cases, the system may further include a controller or processor configured to control the operation of the first heating unit and the second heating unit to adjust the heat load distribution in the reactor module. In some cases, such adjustment of the heat load distribution may be performed in real time based on one or more sensor measurements (e.g., temperature measurements) or based on the performance of the reactor module (e.g., ammonia conversion efficiency and/or thermal efficiency of the reactor module). In some cases, a heater having two or more heating zones may be used to control the power and heat distribution in the heater. In some cases, the system may include multiple heating units. The multiple heating units may include at least two or more heating units. In some cases, the heat load distribution among the at least two or more heating units may be adjustable to increase ammonia conversion efficiency and to improve thermal reforming efficiency of the reactor module. In some cases, each of the at least two or more heating units may have one or more heating zones within the reactor module to enable continuous heat distribution within one or more regions within the reactor module. In some cases, the at least two or more heating units may be configured to heat different zones within the reactor module. In some cases, the at least two or more heating units may be configured to heat one or more of the same zones within the reactor module.

In some embodiments, the reactor module may include a reaction bed comprising one or more ammonia decomposition catalysts including a metallic material, a promoter material, and a support material. The first heating unit and the second heating unit may be configured to heat different portions of the reaction bed. In some cases, the metallic material may include, for example, ruthenium, nickel, rhodium, iridium, cobalt, iron, platinum, chromium, palladium, or copper. In some embodiments, the promoter material may include at least one material selected from Li, Na, K, Rb, Cs, Mg, Ca, Ba, Sr, La, Ce, Pr, Sm, or Gd. In some embodiments, the support may _comprise at _least one material selected from _Al2O3 , _MgO , _CeO2 , _ZrO2 , _La2O3 , _SiO2 , _Y2O3 , _TiO2 , SiC, hexagonal BN (boron nitride), BN nanotubes, silicon carbide, one or more _zeolites , _LaAlO3 , _CeAlO3 , _MgAl2O4 , _CaAl2O4 , or one or more carbon nanotubes _.

In some embodiments, the reactor module may include a cartridge heater design that utilizes one or more electrically insulating materials with a high heat transfer coefficient. In some cases, the one or more electrically insulating materials may include, for example, boron nitride.

In some embodiments, the reactor module may include one or more walls having a thickness ranging from about 0.5 millimeters to about 1.5 millimeters to reduce thermal mass and provide faster and more dynamic temperature response. In some embodiments, the reactor module may include one or more walls having a thickness ranging from about 1.5 millimeters to about 30 millimeters to increase structural integrity. In some embodiments, the reactor module may have a thermal reforming efficiency of at least about 90%. In some cases, the reactor module may have a thermal reforming efficiency of at least about 95%. As used herein, the term "thermal efficiency" or "thermal reforming efficiency" may refer to the percentage of total heat and chemical energy provided to the system that is converted to _H2 chemical energy. In some cases, the "thermal efficiency" or "thermal reforming efficiency" may correspond to the heating value of ammonia and the heating value of hydrogen relative to the actual heat input. In some cases, the "thermal efficiency" or "thermal reforming efficiency" may correspond to the outgoing _H2 chemical energy relative to the incoming _NH3 chemical energy and the incoming heat.

In some cases, the system may further include one or more fuel cells in fluid communication with the reactor module. The one or more fuel cells can be configured to generate electrical energy using hydrogen produced by the reactor module. In some cases, the one or more fuel cells may be in fluid communication with the reactor module and/or a second reactor module. The second reactor module may include, for example, a fast start reactor module as described above. The one or more fuel cells may be configured to generate electrical energy using hydrogen produced by the reactor module and/or the second reactor module.

Method

In another aspect, the disclosure provides a method for processing ammonia to produce hydrogen. The method may include providing a feed material including ammonia to a first reactor module. The first reactor module may include a first catalyst and a start-up heating and reforming unit. The start-up heating and reforming unit may include one or more electrodes for passing an electric current through the first catalyst to heat the first catalyst. The method may further include heating the first catalyst by passing an electric current through at least a portion of the first catalyst using the start-up heating and reforming unit. When the first catalyst is heated using the start-up heating and reforming unit, the first catalyst may be used to produce hydrogen from ammonia.

In some embodiments, the method can include providing hydrogen produced using the first reactor module to one or more fuel cells. The method can further include generating electricity using the one or more fuel cells.

In another embodiment, the method may include supplying hydrogen produced using the first reactor module to a second reactor module in fluid communication with the first reactor module. The second reactor module may also be configured to receive a feed material including ammonia. The feed material may be supplied to the first reactor module and the second reactor module from the same feed. In some cases, the feed material may be supplied to the first reactor module and the second reactor module from different sources. The second reactor module may include a second catalyst and one or more main heating units for heating the second catalyst. The method may further include heating at least a portion of the second catalyst using the one or more main heating units. In some cases, the method may include heating the second catalyst by combusting at least a portion of the hydrogen produced by the first reactor module. Once heated, the second catalyst may be used to produce additional hydrogen from the ammonia received by the second reactor module.

In some embodiments, the method can include supplying hydrogen produced using the second reactor module to one or more fuel cells. In some cases, the method can further include generating electricity using the one or more fuel cells. The electricity can be used to power one or more systems or devices that require power to operate (e.g., various land, air, or underwater vehicles).

In another aspect, the disclosure provides a method for processing ammonia to produce hydrogen. The method can include providing a feed material including ammonia to a reactor module. The reactor module can include a catalyst and a plurality of heating units for heating the catalyst. The plurality of heating units can include a first heating unit configured to heat at least a first portion of the catalyst by combustion and a second heating unit configured to heat at least a second portion of the catalyst using Joule heating. In some cases, the first and second portions of the catalyst can be in contact with or adjacent to each other. In other cases, the first and second portions of the catalyst can be separated by a third portion of the catalyst or a barrier (e.g., a physical barrier or a thermal barrier).

In some embodiments, the method may further include heating a first portion of the catalyst by burning hydrogen. In some embodiments, the method may further include heating a second portion of the catalyst by passing an electric current through the second portion of the catalyst. Once heated, the catalyst may be used to produce hydrogen from a feed material including ammonia. In some cases, the hydrogen burned to heat the first portion of the catalyst may be produced using a second reactor module. Such a second reactor module may be configured to produce (i.e., make or extract) hydrogen from a feed material including ammonia. The second reactor module may include a second catalyst and a second heating unit. In some cases, the second heating unit may be configured to heat the second catalyst by passing an electric current through the second catalyst. Once heated, the second catalyst may be used to produce hydrogen from a feed material received by the second reactor module.

In some embodiments, the method can include supplying hydrogen produced using the reactor module to one or more fuel cells. In some cases, the method can further include generating electricity using the one or more fuel cells. The electricity can be used to power one or more systems or devices that require power to operate (e.g., various land, air, or underwater vehicles).

In some embodiments, the method may further include supplying hydrogen produced using the reactor module to one or more combustion engines. In some cases, the method may further include producing mechanical work using the one or more combustion engines. The mechanical work may be used to power one or more systems or devices that require electrical power to operate (e.g., various land, air, or underwater vehicles).

Computer systems

In one aspect, the present disclosure provides a computer system that is programmed or configured to implement the methods of the present disclosure. FIG. 18 illustrates a computer system 1801 (i.e., a controller or computing device) that can be programmed or configured to implement a system and/or method for processing ammonia. The computer system 1801 can be configured, for example, to (i) control the flow of ammonia-containing feedstock to one or more reactors, (ii) control the operation of one or more heating units to heat one or more catalysts in one or more reactors and use the one or more catalysts to produce hydrogen from the ammonia-containing feedstock after being heated by the one or more heating units, and (iii) control the flow of hydrogen produced from the ammonia to one or more fuel cells to produce electricity. The computer system 1801 can control the flow of feedstock to the reactors and/or the flow of hydrogen from the reactors to one or more fuel cells by adjusting one or more flow control mechanisms (e.g., one or more valves). The computer system 1801 can control the operation of one or more heating units by adjusting the amount of current flowing through one or more catalysts. The computer system 1801 may be a user's electronic device or a computer system located remotely to the electronic device. The electronic device may be a mobile electronic device.

The computer system 1801 may include a central processing unit (CPU, herein "processor" and "computer processor") 1805, which may be a single-core or multi-core processor, or multiple processors for parallel processing. The computer system 1801 may also include memory or storage locations 1810 (e.g., random access memory, read-only memory, flash memory), electronic storage 1815 (e.g., hard disk, solid state disk, etc.), communication interface 1820 (e.g., network adapter) for communicating with one or more other systems, and peripherals 1825, such as cache, other memory, data storage and/or electronic display adapters, etc. The memory 1810, storage 1815, interface 1820 and peripherals 1825 communicate with the CPU 1805 via a communication bus (solid lines), e.g., a motherboard. The storage 1815 may be a data storage device (or data repository) for storing data. The computer system 1801 may be operatively coupled to a computer network (network) 1830 using the communication interface 1820. Network 1830 may be the Internet, an Internet and/or an extranet, or an intranet and/or an extranet in communication with the Internet. In some cases, network 1830 may be a telecommunications network and/or a data network. Network 1830 may include one or more computer servers, thereby enabling distributed computing, such as cloud computing. Network 1830 may, in some cases, implement a peer-to-peer network using computer system 1801, such that devices coupled to computer system 1801 may operate as clients or servers.

The CPU 1805 may execute a sequence of machine-readable instructions, which may be embodied in a program or software. The instructions may be stored in a memory location, such as memory 1810. The instructions may be directed to the CPU 1805, which may then program or configure the CPU 1805 to perform the methods of the present disclosure. Examples of operations performed by the CPU 1805 may include fetch, decode, execute, and writeback.

The CPU 1805 may be part of a circuit, such as an integrated circuit. One or more other components of the system 1801 may also be included in the circuit. In some cases, the circuit may be an application specific integrated circuit (ASIC).

Storage device 1815 may store files, such as drivers, libraries, and saved programs. Storage device 1815 may store user data, such as user settings and user programs. Computer system 1801 may optionally include one or more additional data storage devices located outside computer system 1801 (e.g., on a remote server in communication with computer system 1801 via an intranet or the Internet).

The computer system 1801 may communicate with one or more remote computer systems via the network 1830. For example, the computer system 1801 may communicate with a remote computer system of a user (e.g., an individual operating a reactor, an entity monitoring the operation of the reactor, or an end user operating an apparatus or vehicle that can be powered using electrical energy derived or created from hydrogen produced using the reactor). Examples of remote computer systems include a personal computer (e.g., a portable PC), a slate or tablet PC (e.g., Apple® iPad®, Samsung® Galaxy Tab), a phone, a smartphone (e.g., Apple® iPhone®, Android®-enabled device, BlackBerry®), or a personal digital assistant. A user may access the computer system 1801 via the network 1830.

The systems and methods described in this disclosure can be executed by machine (e.g., computer processor) executable code stored in electronic storage locations of the computer system 1801, such as memory 1810 or electronic storage 1815. The machine executable or machine readable code may be provided in the form of software. In use, the code may be executed by the processor 1805. In some cases, the code may be retrieved from storage 1815 and stored in memory 1810 for rapid access by the processor 1805. In some cases, the electronic storage 1815 may be omitted and the machine executable instructions are stored in memory 1810.

The code may be pre-compiled and configured for use on a machine having a processor configured to execute the code, or may be compiled on the fly. The code may be provided in a programming language that can be selected so that the code can be executed in a pre-compiled or compiled form.

Aspects of the systems and methods provided herein, such as the computer system 1801, can be embodied in programming. Various aspects of the technology can be thought of as a "product" or "article of manufacture," typically in the form of machine (or processor) executable code and/or associated data carried on or embodied in a type of machine-readable medium. The machine-executable code can be stored on electronic storage, such as memory (e.g., read-only memory, random access memory, flash memory) or a hard disk. A "storage" type medium may include any or all of the tangible memory of a computer, processor, etc., or their associated modules, such as various semiconductor memories, tape drives, disk drives, etc., which can provide non-transitory storage at any time for software programming. All or a portion of the software may sometimes be communicated over the Internet or various other communications networks. Such communication can, for example, allow the software to be loaded from one computer or processor to another, such as from a management server or host computer to an application server computer platform. Thus, other types of media that may carry software elements include optical, electrical, and electromagnetic waves used across physical interfaces between local devices, over wired and optical landline networks, and over various air links. The physical elements that transmit such waves, e.g., wired or wireless links, optical links, etc., may also be considered media carrying the software. As used herein, unless limited to non-transitory, tangible "storage" media, the term, e.g., computer or machine "readable medium," refers to any medium that participates in providing instructions to a processor for execution.

Thus, the machine-readable medium, e.g., computer executable code, can take many forms, including but not limited to tangible storage media, carrier wave media, or physical transmission media. For example, non-volatile storage media, including optical or magnetic disks, or any storage device, such as any computer, may be used to implement the databases, etc., shown in the drawings. Volatile storage media may include dynamic memory, e.g., the main memory of such a computer platform. Tangible transmission media may include wiring, including coaxial cables, copper wire, and fiber optics, including buses within a computer system. Carrier wave transmission media may take the form of electric or electromagnetic signals, or acoustic or light waves, such as those generated during radio frequency (RF) and infrared (IR) communications. Thus, common forms of computer readable media include, for example, floppy disks, flexible disks, hard disks, magnetic tape, any other magnetic media, CD-ROMs, DVDs or DVD-ROMs, any other optical media, punched card paper tape, any other physical storage media with a pattern of holes, RAM, ROM, PROMs and EPROMs, FLASH-EPROMs, any other memory chips or cartridges, carrier waves transmitting data or instructions, cables or links transmitting such carrier waves, or any other medium from which a computer can read programming code and/or data. Many of these forms of computer readable media may be involved in transmitting one or more sequences of one or more instructions to a processor for execution.

The computer system 1801 may include or communicate with an electronic display 1835 with a user interface (UI) 1840 to provide a portal for a user to monitor or track the operation or performance of, for example, one or more reactors or one or more components of a reactor. In some cases, the performance of the one or more reactors may include, for example, the ammonia conversion efficiency or thermal efficiency of the one or more reactors. The portal may be provided through an application programming interface (API). A user or entity may also interact with various elements in the portal through the UI. Examples of UIs include, but are not limited to, graphical user interfaces (GUIs) and web-based user interfaces.

The methods and systems of the present disclosure may be implemented by one or more algorithms. The algorithm may be implemented by software when executed by the central processing unit 1805. For example, the algorithm may be configured to control the operation of one or more reactors based on one or more sensor measurements (e.g., temperature measurements, flow rates, etc.) or based on the performance of one or more reactors. In some cases, the algorithm may be configured to (i) control the flow of ammonia-containing feedstock material to one or more reactors, (ii) control the operation of one or more heating units to heat one or more catalysts of one or more reactors, which may produce or extract hydrogen from the ammonia-containing feedstock material after the one or more catalysts are heated by the one or more heating units, and/or (iii) control the flow of hydrogen produced from the ammonia to one or more fuel cells to generate electricity. In some cases, the algorithm may be configured to control, modify, or adjust the heat load distribution between the first heating unit and the second heating unit of the reactor to increase ammonia conversion efficiency and improve the thermal efficiency of the reactor module. The heat load distribution may include a heating power ratio corresponding to a ratio between the heating power of the first heating unit and the heating power of the second heating unit. The algorithm can adjust the heating power of the first heating unit and the second heating unit using various monitor or sensor measurements or various parameters associated with the reactor performance to achieve a desired ammonia conversion efficiency and/or reactor thermal efficiency.

System configuration

FIG. 19 shows a compact ammonia power pack system with a heat exchanger for the outlet stream from the primary reactor R_m. The outlet stream from the primary reactor R_m may be cooled using a heat exchanger (HX) before entering the adsorption tower (ADS). The heat exchanger can be used to facilitate the transfer of thermal energy between the outlet stream (which may contain hydrogen, nitrogen, and/or low ppm unconverted ammonia) and a heat sink (e.g., an ammonia storage tank) or a fluid medium (e.g., ambient air). The heat exchanger may be in thermal communication with the ambient air and cool the outlet stream from the primary reactor R_m to less than about 50 degrees Celsius. Alternatively, the heat exchanger may be in thermal communication with one or more ammonia storage tanks and cool the outlet stream from the primary reactor R_m to less than about 50 degrees Celsius and provide heating energy for ammonia evaporation in the storage tank. Alternatively, the heat exchanger may be in thermal communication with one or more ammonia inflows to cool the outlet stream from the primary reactor R_m to less than about 50 degrees Celsius and provide heat or thermal energy for ammonia evaporation in the heat exchanger. The cooled outlet stream may be directed to one or more adsorption towers to remove any traces of ammonia from the cooled outlet stream before the outlet stream is directed to the one or more fuel cells. The adsorption towers may help maintain the performance and/or life of the one or more fuel cells, as ammonia can be detrimental to the performance of the fuel cells. The adsorption towers may comprise one or more adsorbents that can be replaceable (e.g., cartridge type) after a certain number of cycles or operations. The one or more adsorbents may be configured to filter or remove unconverted ammonia and/or nitrogen from the outlet stream from the one or more reactors.

FIG. 20 illustrates an ammonia power pack system with a heat exchanger for cooling the outlet stream of the primary reactor R_m using the inlet stream. The heat exchanger can be in thermal communication with an ammonia storage tank to facilitate cooling of the outlet stream from R_m and provide thermal energy for ammonia evaporation in the storage tank. In some embodiments, the ammonia storage tank can be in thermal communication with a fuel cell to recover waste heat from the fuel cell and provide heating energy for ammonia evaporation in the ammonia storage tank. The inlet and outlet streams of the reactor can be in thermal communication with each other via a heat exchanger for heat recovery. In some cases, the inlet stream (which may include ammonia from one or more ammonia tanks) may be heated or preheated before entering the primary reactor R_m. The inlet stream may be heated or preheated by the transfer of thermal energy between the inlet stream and the outlet stream. The outlet stream may include hydrogen and/or nitrogen created by decomposition of ammonia in the inlet stream. The transfer of thermal energy between the outlet stream and the inlet stream and/or the ammonia storage tank cools the outlet stream, which can then enter an adsorption tower upstream of one or more fuel cells configured to utilize at least a portion of the outlet stream (e.g., hydrogen) to generate electrical energy.

FIG. 21 illustrates an ammonia power pack system comprising a heat exchanger for cooling both the inlet and outlet streams of the primary reactor R_m. The ammonia power pack system may further comprise a start-up reactor R_s as described elsewhere herein. The start-up reactor may be configured to decompose the ammonia within a predetermined time to start the reactor. The predetermined time may be up to about 5 minutes or less. In some embodiments, the predetermined time may be up to about 60 minutes or less. The start-up reactor may be powered by electrical energy (e.g., by passing an electrical current through a conductive catalytic material for heat generation). The start-up reactor may comprise a catalyst configured to decompose the ammonia when heated to a threshold temperature (e.g., above 350 degrees Celsius). The decomposition of ammonia may produce hydrogen that may be directed from the start-up reactor R_s to the heating unit of the primary reactor R_m for combustion heating, as described elsewhere herein. In some cases, during high power demand, the start-up reactor may operate as a load-following unit. The inlet stream into the primary reactor R_m may include ammonia, nitrogen, and/or hydrogen. The inlet stream to the main reactor R_m may include ammonia from one or more ammonia tanks, or nitrogen, hydrogen, and/or unconverted ammonia from the start-up reactor R_s.

FIG. 22 shows an ammonia power pack for powering a larger system (e.g., a system having a required power of at least about 100 kilowatts or more). The power pack system can include a start-up reactor R_s, a main reactor R_m, and multiple adsorption towers (ADS). In some cases, the adsorption towers can include adsorption material provided in a cartridge type. However, the adsorption material may not be or need not be in a cartridge type. In some cases, two adsorption beds may be utilized for on-demand adsorption regeneration and continuous operation of the ammonia power pack system. In some cases, a first adsorption tower may be used or operated for a first period of time, and a second adsorption tower may be in a standby state ready to be used or operated. Once the first ADS is fully discharged, the system can switch the flow path of the outlet stream from the main reactor R_m to the second ADS. The second ADS can be used to remove any traces of ammonia from the outlet stream before the outlet stream is directed to one or more fuel cells. While the second ADS is being used, the first ADS can be regenerated. Once the second ADS is fully discharged, the first ADS is regenerated and ready for use in another cycle or operation. In any of the embodiments described herein, two, three, four, five, six, seven, eight, nine, ten, or more adsorption towers can be used.

As shown in FIG. 23, one or more additional heat exchangers may be provided in some cases. One or more additional heat exchangers may be used to regenerate various adsorption beds. For example, adsorption bed 1 (ADS_1) may be regenerated using an embedded electric heater (H_3). A pump or blower may be used to remove the regenerated ammonia and the regenerated ammonia stream may be combined with the outlet stream from the fuel cell (which may contain unconverted _H2 and/or _N2 ). The ammonia may be released into the fuel cell outlet stream. The combination of the fuel cell outlet stream and ammonia may be directed to the primary reactor R_m for combustion to heat the primary reactor R_m for further ammonia decomposition.

After the adsorbent is regenerated, the adsorption bed may be cooled for the next cycle. For example, if adsorption bed 2 (ADS_2) is regenerated, the flow path between ADS_2 may be closed or restricted using a valve, and the flow path shown by the dotted line (i.e., the dotted line between ADS_2 and pump or blower P) may allow the regenerated ammonia from ADS_2 to be directed toward the combustion reaction stream that provides H_2 for combustion heating of the main reactor R_m. In such a case, ADS_1 may then allow the outlet stream of the main reactor R_m to flow through ADS_1 toward the fuel cell.

As shown in FIG. 24, one or more additional heat exchangers may be provided in some cases. One or more additional heat exchangers may be used to regenerate the various adsorbent beds. For example, adsorbent bed 1 may be regenerated using an embedded combustion heater (H_3). In some cases, combustion by-products from H_3, primarily water vapor, may be vented to the atmosphere. A pump or blower may be used to remove the regenerated ammonia and combine the regenerated ammonia stream with the outlet stream from the fuel cell (which may contain unconverted _H2 and/or _N2 ). The ammonia may be vented into the fuel cell outlet stream. The combination of the fuel cell outlet stream and ammonia may be directed to the primary reactor R_m for combustion to heat the primary reactor R_m, removal of ammonia desorbed from the adsorber, and/or further ammonia decomposition. In some embodiments, the exhaust stream from one or more combustion reactors or heaters (e.g., H_2 in FIG. 24) may be used for adsorber regeneration.

In some cases, ambient air (e.g., a portion of the air from the main reactor (R_m) combustor heater (H_2) air intake), as well as _H2 and/or _N2 from the fuel cell outlet stream may be drawn or directed to the adsorption-combustion heater H_3 for regeneration. In some cases, one or more flow control units (e.g., valves) may be used to direct the fuel cell outlet stream to a different combustion heater H_3. In some embodiments, the regenerated ammonia, unconverted hydrogen, and/or nitrogen exiting the first adsorption-combustion heater H_3 may be vented to the environment. After one or more adsorption beds are regenerated, the adsorption beds may be cooled for one or more subsequent cycles, thereby enabling continuous operation.

As shown in FIG. 25, in some cases, three or more adsorption towers can be used in a single ammonia power pack system. The power pack system shown in FIG. 25 can be adapted to larger system configurations (e.g., electric vehicles with power requirements of 100 kW or more). In some configurations, two adsorption beds can be available for on-demand adsorber regeneration and continuous operation. Another additional adsorption bed (e.g., ADS_3) can be utilized as a fuel cell safety mechanism (e.g., in case of incomplete regeneration of ADS_1 and ADS_2 during operation of the ammonia power pack system). In some cases, the adsorption materials of ADS_1 and ADS_2 can be the same, and the adsorption material of ADS_3 can be different from the adsorption materials of ADS_1 and ADS_2. In some embodiments, a combination of different adsorption materials can be used to increase the _NH3 adsorption efficiency or capacity of the entire system.

Another embodiment

In some cases, the ammonia powerpack system may include a start-up reactor for dynamic load following (e.g., by controlling ammonia flow rate and electrical heating). In some cases, the ammonia powerpack system may include a main reactor for dynamic load following (e.g., by controlling ammonia flow rate and the amount of _H2 combustion or electrical heating, or a combination of both).

In some cases, the ammonia power pack system may include a battery for dynamic load following. The main reactor may be configured to maintain a constant power output, and the on-board battery can provide dynamic load following functionality (i.e., discharge when the load is high and charge when the load is low).

In some cases, the ammonia power pack system can be equipped with an emergency shutoff feature. The emergency shutoff feature can be implemented using sensors configured to monitor the ammonia ppm levels at the adsorption bed inlet and the fuel cell inlet, and shut off or reduce the ammonia flow rate if the ammonia ppm level exceeds a certain threshold limit (e.g., about 10 ppm at the fuel cell inlet).

In some cases, the ammonia power pack system may include an adsorption switch having one or more embedded ammonia sensors. The ammonia sensors may be configured to monitor the ammonia concentration in the adsorber. The outlet stream of _N2 and/or _H2 from the reactor may be switched to the next adsorber if the ammonia level exceeds a certain threshold level (e.g., at least about 10 ppm).

In some cases, the adsorbent material may include a combination of an adsorbent (e.g., a zeolite) and a metal salt (e.g., MgCl2), which can further reduce the ammonia ppm levels in the primary reactor outlet stream.

In some cases, the ammonia power pack system may enable ammonia flow control to maintain and/or adjust the reactor temperature (e.g., increasing the ammonia flow rate may decrease the reactor temperature). This control may prevent or reduce the risk of overheating and maintain an optimal temperature for ammonia decomposition.

In any of the embodiments described herein, the ammonia power pack unit may include one or more reactors and one or more fuel cells that are mounted, fixed, or affixed to a common frame, such that the one or more reactors and one or more fuel cells can be configured to operate as an integrated power pack system.

Packaging and assembly

In another aspect, the present disclosure provides various exemplary configurations for packaging and assembly of an ammonia power pack system. The ammonia power pack system can have any of the components or system configurations described elsewhere herein.

As shown in FIG. 26, in some cases, the ammonia power pack system may include one or more fuel cell units. The ammonia power pack system may further include one or more ammonia tanks coupled to or disposed adjacent to the one or more fuel cell units. In some cases, the one or more ammonia tanks may be disposed on top of the one or more fuel cell units. The ammonia power pack system may further include a main reactor R_m and a start-up reactor R_s, as described above. The ammonia tank may be in fluid communication with the main reactor R_m and/or the start-up reactor R_s. Ammonia may flow from the ammonia tank to the start-up reactor R_s and/or the main reactor R_m. The main reactor R_m and the start-up reactor R_s may be coupled to or disposed adjacent to one or more sides of the fuel cell unit. In some cases, the main reactor R_m and the start-up reactor R_s may be disposed on different sides of the fuel cell unit. The main reactor R_m and the start-up reactor R_s may be in fluid communication with each other such that one or more fluids or materials from the start-up reactor R_s can flow to the main reactor R_m. In some cases, the fuel cell unit may also be in fluid communication with the primary reactor R_m. In some cases, unconverted hydrogen from the fuel cell unit may be directed to the primary reactor R_m for combustion heating to heat the primary reactor. In some cases, the cell unit may be operatively coupled to any valves or other flow control units for controlling the flow of various fluids or materials between the fuel cell unit, the primary reactor R_m, the start-up reactor R_s, the ammonia tank, and/or components of the ammonia power pack system. The cell unit may be coupled to a portion of the fuel cell unit.

In some cases, the ammonia power pack system may include a heat exchanger and/or an adsorption tower, as described elsewhere herein. The heat exchanger and adsorption tower may be in fluid communication with the primary reactor R_m. The heat exchanger and adsorption tower may be coupled to or disposed adjacent to a portion of the fuel cell unit. In some embodiments, the heat exchanger and adsorption tower may be disposed on a first side of the fuel cell unit. In some cases, the primary reactor R_m may be disposed on a second side of the fuel cell unit, the start-up reactor R_s may be disposed on a third side of the fuel cell unit, and the cell unit may be disposed on a fourth side of the fuel cell unit. The ammonia tank may be disposed on a fifth side of the fuel cell unit. The ammonia power pack configuration shown in FIG. 26 can be utilized for compact systems (e.g., systems having a power requirement of less than about 100 kilowatts).

As shown in FIG. 27, in some cases, the ammonia power pack system is suitable for larger systems (e.g., systems having a required power of more than 100 kilowatts). The ammonia power pack system may include an ammonia tank, a heat exchanger, a startup reactor R_s, a main reactor R_m, one or more adsorption towers, a fuel cell unit, and a battery unit. The heat exchanger, startup reactor R_s, main reactor R_m, one or more adsorption towers, a fuel cell unit, and a battery unit may be disposed adjacent to the ammonia tank. The ammonia tank may be in fluid communication with the heat exchanger. Ammonia from the ammonia tank may flow through the heat exchanger into the startup reactor R_s for processing. Hydrogen and/or nitrogen made from the decomposition of ammonia may be directed from the startup reactor to the main reactor. Hydrogen extracted from the ammonia by the startup reactor may be combusted in the main reactor to heat the main reactor. In some cases, ammonia from the ammonia tank and/or unconverted ammonia from the startup reactor may be directed to the main reactor R_m for cracking or decomposing ammonia. When ammonia is cracked using the primary reactor R_m, products including hydrogen and nitrogen can be directed from the primary reactor to a heat exchanger to cool the outlet stream before the hydrogen and/or nitrogen in the outlet stream is directed to one or more adsorption towers. In some cases, the outlet stream may include unconverted ammonia in addition to hydrogen and/or nitrogen. In such a case, the outlet stream can be directed to the first adsorption tower during a first period of time and to the second adsorption tower during a second period of time to remove the unconverted ammonia. The first period of time can correspond to a period during which the second adsorption tower is regenerated. The second period of time can correspond to a period during which the first adsorption tower is regenerated. The adsorption towers can be used to remove any excess ammonia before the outlet stream including hydrogen and/or nitrogen is directed to the fuel cell unit. The fuel cell unit can be configured to generate electrical energy using hydrogen. In some cases, the unconverted hydrogen can be returned to the primary reactor R_m for combustion heating to heat the primary reactor.

FIG. 28 illustrates a schematic of an ammonia power pack system that may be adapted for use in an aerial vehicle. The aerial vehicle may include, for example, a manned aerial vehicle, an unmanned aerial vehicle, an aircraft, an airplane, a helicopter, or a drone. The configuration of the ammonia power pack system illustrated in FIG. 28 may be similar to the configuration illustrated in FIG. 26. In some cases, the ammonia power pack system may be integrated into the body of the aerial vehicle. In other cases, the ammonia power pack system may be located on top of or underneath the body of the aerial vehicle.

Figure 29 shows a schematic of another example of an ammonia power pack system that may be adapted for use in an aviation vehicle. The ammonia power pack system may include an ammonia tank, one or more fuel cell units, a battery unit, a start-up reactor R_s, a main reactor R_m, a heat exchanger, and an adsorption tower. The one or more fuel cell units, the battery unit, the start-up reactor R_s, the main reactor R_m, the heat exchanger, and the adsorption tower may be arranged around the ammonia tank. The ammonia power pack system may be located on top of or under a portion of the aviation vehicle. Alternatively, the ammonia power pack system may be integrated with a structural portion or component of the aviation vehicle.

Figure 30 shows a schematic of an example of an ammonia power pack system that may be adapted for use in a land vehicle, e.g., a car or automobile. The ammonia power pack system may comprise one or more fuel cells, one or more adsorption towers, a start-up reactor R_s and/or a main reactor R_m, a heat exchanger, a battery unit, and an ammonia tank. The one or more fuel cells may be located in or near the front of the vehicle (e.g., in the engine compartment of the vehicle). The adsorption towers, start-up reactor R_s, main reactor R_m, and heat exchanger may be located in or near the underside area of the vehicle. The ammonia tank may be located near the rear end of the vehicle. The battery unit may be located between the ammonia tank and other components of the ammonia power pack system.

Figure 31 shows, in schematic form, another example of an ammonia power pack system that may be adapted for use in a land vehicle, e.g., a car or automobile. The ammonia power pack system may comprise one or more fuel cells, one or more adsorption towers, a start-up reactor R_s and/or a main reactor R_m, a heat exchanger, a battery unit, and an ammonia tank. The one or more fuel cells and the one or more adsorption towers may be located in or near the underside region of the vehicle. The ammonia tank and the battery unit may be located near the axle of the vehicle (e.g., the rear axle of the vehicle). The start-up reactor R_s, the main reactor R_m, and the heat exchanger may be located in or near the front of the vehicle (e.g., in the engine compartment of the vehicle).

Figures 32-35 show schematics of an example ammonia power pack system that may be adapted for use in a land vehicle, such as a truck or semi-trailer truck. The ammonia power pack system may include one or more fuel cells, one or more adsorption towers, one or more start-up reactors, one or more main reactors, one or more heat exchangers, one or more battery units, and/or one or more ammonia tanks.

In some cases, the ammonia tank or tanks may be coupled to or incorporated into the rear of a tractor unit of a truck. The tractor unit (also known as a prime mover, truck, truck trailer, semi-tractor, rig, big rig, or simply tractor) may have a heavy-duty traction engine that provides power for hauling or trailering loads. In some cases, the fuel cell unit or units may be located in or near the front of the tractor unit (e.g., in the engine compartment of the tractor unit), as shown in FIG. 32. In such cases, the adsorption tower or towers, the start-up reactor or reactors, the main reactor or reactors, the heat exchanger or reactors, and the battery unit or units may be located in or near the lower area of the tractor unit. In other cases, the start-up reactor or reactors and the main reactor or reactors may be located in or near the front of the tractor unit (e.g., in the engine compartment of the tractor unit), as shown in FIG. 33. In such cases, the adsorption tower or towers, the heat exchanger or reactors, the battery unit or units, and the fuel cell unit or units may be located in or near the lower area of the tractor unit.

34 shows a schematic diagram of an example of an ammonia power pack system that may be adapted for use in a land vehicle, such as a truck or semi-trailer truck. In some cases, as shown in FIG. 34, the ammonia power pack system may include multiple power pack modules. The multiple power pack modules may include at least one power pack including a main reactor R_m, a start-up reactor R_s, and a heat exchanger. The multiple power pack modules may be located in or near the underside area of the tractor unit. The multiple power pack modules may be distributed along the underside of the tractor unit. In some cases, the fuel cell or fuel cells may be located in or near the front of the tractor unit (e.g., in the engine compartment of the tractor unit). In some cases, the adsorption tower or towers and the battery unit or units may be located between the fuel cell or fuel cells and the multiple power pack modules.

35 shows another example of an ammonia power pack system that may be adapted for use in a land vehicle, such as a truck or semi-trailer truck. As shown in FIG. 35, the ammonia power pack system may include a plurality of power pack modules. The plurality of power pack modules may include at least one power pack including a main reactor R_m, a start-up reactor R_s, and a heat exchanger. The plurality of power pack modules may be disposed in or near the front of the tractor unit (e.g., in the engine compartment of the tractor unit). In some cases, the one or more power pack modules may be disposed near an axle (e.g., the front axle) of the tractor unit. In some cases, the one or more power pack modules may be disposed in or near the underside area of the tractor unit. In some cases, the one or more fuel cells, the one or more battery units, and/or the one or more adsorption towers may be disposed under or near the tractor unit. In some cases, the one or more adsorption towers and the one or more battery units may be disposed between the one or more fuel cells and the plurality of power pack modules.

In some cases, the multiple power pack modules may be located adjacent to one another. In other cases, the multiple power pack modules may be located apart from one another (i.e., in or on different sides, areas, or sections of the vehicle). In some cases, the multiple power pack modules may be oriented in the same direction. In other cases, at least two of the multiple power pack modules may be oriented in different directions. In any of the embodiments described herein, the multiple power pack modules may be appropriately positioned and/or oriented to maximize volumetric efficiency and minimize the physical footprint of the multiple power pack modules. In any of the embodiments described herein, the multiple power pack modules may be positioned and/or oriented to fit the size and/or shape of the vehicle in which the power pack modules are located or provided. In any of the embodiments described herein, the multiple power pack modules may be positioned and/or oriented to fit the size and/or shape of the vehicle to which the power pack modules are coupled or attached.

In any of the embodiments described herein, the components of the power pack disclosed herein can be located in or on different sides, regions, or sections of the vehicle. In some cases, a first subset of the power pack components may be located away from a second subset of the power pack components. The components of the power pack system can be appropriately located and/or oriented to maximize volumetric efficiency and minimize the physical footprint of the power pack system. The components of the power pack system can be located and/or oriented to fit the size and/or shape of the vehicle in or on which the power pack system is located or provided. The components of the power pack system can be located and/or oriented to fit the size and/or shape of the vehicle to which the power pack system is coupled or attached.

80A illustrates a power pack according to one or more embodiments of the present disclosure. In some cases, the power pack with the reformer and fuel cell may be mounted on a tractor. FIG. 80B illustrates a schematic of a tractor with a mounted power pack according to one or more embodiments of the present disclosure. In some cases, the power pack with the reformer and fuel cell may be mounted within the chassis of the tractor. In some cases, the power pack with the reformer and fuel cell may be located within the hood or trunk of the tractor. In some cases, the components of the power pack may be mounted or integrated into various parts or structural components of the tractor. The components may be mounted in different areas or parts of the tractor to optimize the weight balance and/or center of gravity. In some cases, one or more auxiliary batteries may assist with the power needs of the tractor and/or power the start-up process. In some cases, an ammonia storage tank may be located at the rear of the vehicle. In some cases, fuel cell heat removal via a heat exchanger (or radiator) may be used to vaporize the liquid ammonia fuel before it enters the reactor.

In another aspect, the present disclosure provides a system for decomposing ammonia to produce hydrogen. The system can include one or more reactors and one or more combustors for heating the one or more reactors, as described in more detail below. Figures 36A-36C illustrate schematics of several exemplary systems for decomposing ammonia, according to one or more embodiments of the present disclosure.

The system may include any number of the various components disclosed herein. In some cases, the system may include an ammonia tank. In some cases, the system may include a reactor. In some cases, the reactor may be in fluid communication with the ammonia tank. In some cases, the system may include one or more adsorbents. In some cases, the system may include one or more fuel cells.

The reactor may comprise any number of reactor structures or configurations disclosed herein and may be configured to perform any number of the various functions of the reactors disclosed herein. In some cases, the reactor may be configured to decompose ammonia received from an ammonia tank to produce a reactor outlet stream that includes at least hydrogen.

Optionally, the reactor outlet stream may further comprise undecomposed ammonia. Optionally, the reactor outlet stream may further comprise nitrogen.

The reactor outlet stream may have a variety of flow rates. In some cases, the reactor outlet stream may have a flow rate of at least about 10 liters/minute to a maximum of about 20 liters/minute (e.g., at standard temperature and pressure). In some cases, the reactor outlet stream may have a flow rate of at least about 0.1 liters/minute (lpm) to a maximum of about 100 lpm. In some cases, the reactor outlet stream may have a flow rate of at least about 10 lpm to a maximum of about 500 lpm. In some cases, the reactor outlet stream may have a flow rate of at least about 100 lpm to a maximum of about 1000 lpm. In some cases, the reactor outlet stream may have a flow rate of at least about 500 lpm to a maximum of about 10,000 lpm.

The reactor outlet stream may be at a variety of temperatures. In some cases, the reactor outlet stream may be at a temperature of at least about 100, 200, 300, 400, 500, or 600°C. In some cases, the reactor outlet stream may be at a temperature of up to about 100, 200, 300, 400, 500, or 600°C. In some cases, the reactor outlet stream may be at a temperature of at least about 20°C to up to about 1000°C. In some cases, the reactor outlet stream may be at a temperature of at least about 100°C to up to about 500°C.

The reactor outlet stream may be at a variety of pressures. In some cases, the reactor outlet stream may be at a pressure of at least about 1 bar to a maximum of about 5 bar. In some cases, the reactor outlet stream may be at a pressure of at least about 0.1 bar (gauge) to a maximum of about 20 bar (gauge). In some cases, the reactor outlet stream may be at a pressure of at least about 1 bar (gauge) to a maximum of about 100 bar (gauge).

Hydrogen may comprise various percentages of the reactor outlet stream. In some cases, hydrogen may comprise at least about 0.1 mole fraction and up to about 0.75 mole fraction of the reactor outlet stream.

Uncracked ammonia may comprise various percentages of the reactor outlet stream. In some cases, uncracked ammonia may comprise up to about 0.9 mole fraction of ammonia in the reactor outlet stream. In some cases, uncracked ammonia may comprise up to about 0.05 mole fraction of ammonia in the reactor outlet stream. In some cases, uncracked ammonia may comprise up to about 0.005 mole fraction of ammonia in the reactor outlet stream. In some cases, uncracked ammonia may comprise up to about 0.0005 mole fraction of ammonia in the reactor outlet stream.

Nitrogen may comprise various percentages of the reactor outlet stream. In some cases, nitrogen may comprise at least about 0.05 mole fraction to up to about 0.25 mole fraction of the reactor outlet stream.

The one or more adsorbents may comprise any number of the adsorbent structures or configurations disclosed herein and can be configured to perform any number of the various functions of the adsorbents disclosed herein. In some cases, the one or more adsorbents can be configured to filter or remove unconverted ammonia from at least a portion of the reactor outlet stream to provide a filtered reactor outlet stream.

The one or more adsorber may be configured to filter or remove various percentages of unconverted ammonia from at least a portion of the reactor outlet stream. In some cases, the one or more adsorber may be configured to filter or remove at least about 10 ppm to up to about 100,000 ppm of unconverted ammonia. In some cases, the one or more adsorber may be configured to produce a filtered product stream having less than 10 ppm ammonia.

The one or more adsorbents can be configured to filter or remove various portions of the reactor outlet stream. In some cases, the one or more adsorbents can be configured to filter or remove at least about 10 ppm and up to about 100,000 ppm of ammonia from the reactor outlet stream. In some cases, the one or more adsorbents can be configured to filter or remove at least about 10 ppm and up to about 500,000 ppm of ammonia from the reactor outlet stream.

The filtered reactor outlet stream may have a variety of flow rates. In some cases, the filtered reactor outlet stream may have a flow rate of at least about 10 lpm (standard temperature and pressure) to a maximum of about 20 lpm. In some cases, the filtered reactor outlet stream may have a flow rate of at least about 0.1 liters per minute (lpm) to a maximum of about 100 lpm. In some cases, the filtered reactor outlet stream may have a flow rate of at least about 100 lpm to a maximum of about 500 lpm. In some cases, the filtered reactor outlet stream may have a flow rate of at least about 200 lpm to a maximum of about 1000 lpm.

The filtered reactor outlet stream may be at a variety of temperatures. In some cases, the filtered reactor outlet stream may be at a temperature of at least about 100, 200, 300, 400, 500, or 600°C. In some cases, the filtered reactor outlet stream may be at a temperature of up to about 100, 200, 300, 400, 500, or 600°C. In some cases, the filtered reactor outlet stream may be at a temperature of at least about 20°C to up to about 1000°C. In some cases, the filtered reactor outlet stream may be at a temperature of at least about 100°C to up to about 500°C.

The filtered reactor outlet stream may be at a variety of pressures. In some cases, the filtered reactor outlet stream may be at a pressure of at least about 0.1 bar (gauge) up to about 100 bar.

Hydrogen may comprise various percentages of the filtered reactor effluent stream. In some cases, hydrogen may comprise at least about 0.1 mole fraction and up to about 0.75 mole fraction of the filtered reactor effluent stream.

Undecomposed ammonia may constitute various percentages of the filtered reactor outlet stream. In some cases, the filtered reactor outlet stream may include up to about 100 ppm ammonia. In some cases, the filtered reactor outlet stream may include up to about 10 ppm ammonia. In some cases, the filtered reactor outlet stream may include up to about 1 ppm ammonia. In some cases, the filtered reactor outlet stream may include at least about 0.1 ppm ammonia and up to about 1000 ppm ammonia. In some cases, the filtered reactor outlet stream may include less than 0.1 ppm ammonia.

Nitrogen may comprise various percentages of the filtered reactor effluent stream. In some cases, nitrogen may comprise at least about 0.05 mole fraction to up to about 0.25 mole fraction of the filtered reactor effluent stream.

In some cases, the one or more fuel cells may be in fluid communication with the reactor. In some cases, the one or more fuel cells may be in fluid communication with the one or more adsorbers. In some cases, the one or more fuel cells may be configured to receive a filtered reactor outlet stream from the one or more adsorbers. In some cases, the one or more fuel cells may be configured to process the filtered reactor outlet stream to generate electricity. In some cases, the one or more fuel cells may be configured to output a fuel cell outlet stream that includes unconverted hydrogen. In some cases, the fuel cell outlet stream may further include hydrogen. In some cases, the fuel cell outlet stream may further include nitrogen.

The one or more fuel cells can generate various amounts of electricity. In some cases, the one or more fuel cells can generate at least about 400 W and up to about 600 W of electricity. In some cases, the one or more fuel cells can generate at least about 10 W and up to about 1 MW of electricity. In some cases, the one or more fuel cells can generate at least about 100 kW and up to about 1000 kW of electricity. In some cases, the one or more fuel cells can generate at least about 1 MW and up to about 10 MW of electricity.

The fuel cell outlet stream may be at a variety of flow rates. In some cases, the fuel cell outlet stream may be at a temperature of at least about 100, 200, 300, 400, 500, or 600°C. In some cases, the fuel cell outlet stream may be at a temperature of up to about 100, 200, 300, 400, 500, or 600°C. In some cases, the fuel cell outlet stream may be at a temperature of at least about 20°C and up to about 1000°C. In some cases, the fuel cell outlet stream may be at a temperature of at least about 100°C and up to about 500°C.

The fuel cell outlet stream may be at a variety of pressures. In some cases, the fuel cell outlet stream may be at a pressure of at least about 0.01 bar (gauge) up to about 10 bar (gauge).

Hydrogen may comprise various percentages of the fuel cell outlet stream. In some cases, hydrogen may comprise at least about 0.01 mole fraction and up to about 0.75 mole fraction of the fuel cell outlet stream.

Undecomposed ammonia may comprise various percentages of the fuel cell outlet stream. In some cases, undecomposed ammonia may comprise at least about 1 ppm and up to about 100 ppm of the fuel cell outlet stream. In some cases, undecomposed ammonia may comprise at least about 0.01 ppm and up to about 1 ppm of the fuel cell outlet stream.

Nitrogen may comprise various percentages of the fuel cell outlet stream. In some cases, nitrogen may comprise at least about 0.25 mole fraction and up to about 1 mole fraction of the fuel cell outlet stream.

Combustor design

In some cases, the combustor(s) may be in fluid communication with an ammonia tank. In some cases, the combustor(s) may be in fluid communication with a reactor. In some cases, the combustor(s) may be in fluid communication with one or more adsorbers. In some cases, the combustor(s) may be in fluid communication with one or more fuel cells. In some cases, the combustor(s) may be in fluid communication with an ammonia tank, a reactor, one or more adsorbers, one or more fuel cells, or any combination thereof.

In some cases, as shown in FIG. 36A, the one or more combustors can be configured to combust at least a portion of the reactor outlet stream to generate thermal energy for heating the reactor and/or the catalytic material within the reactor. In some cases, as shown in FIG. 36B, the one or more combustors may be configured to combust at least a portion of the filtered reactor outlet stream to generate thermal energy for heating the reactor. In some cases, as shown in FIG. 36C, the one or more combustors may be configured to combust at least a portion of the fuel cell outlet stream to generate thermal energy for heating the reactor. In some cases, the one or more combustors may be configured to combust at least a portion of the reactor outlet stream to heat multiple different regions within the reactor. In some cases, the one or more combustors may be configured to combust at least a portion of the fuel cell outlet stream to heat multiple different regions within the reactor.

Various portions of the reactor outlet stream may be combusted by one or more combustors. In some cases, at least about 5% and up to about 50% of the hydrogen from the reactor outlet stream may be combusted by one or more combustors.

Various portions of the filtered reactor outlet stream may be combusted by one or more combustors. In some cases, at least about 5% and up to about 50% of the hydrogen from the filtered reactor outlet stream may be combusted by one or more combustors.

Various portions of the fuel cell outlet stream may be combusted by one or more combustors. In some cases, at least about 10% and up to about 100% of the hydrogen from the fuel cell outlet stream may be combusted by one or more combustors.

In some cases, the system may further include an air supply unit. In some cases, the air supply unit may be in fluid communication with the one or more combustors. In some cases, the air supply unit may be configured to supply at least oxygen to the one or more combustors. In some cases, the air supply unit may be configured to supply air from the atmosphere to the one or more combustors.

The air supply unit may supply oxygen to one or more combustors at various flow rates. In some cases, the air supply unit may supply oxygen at a flow rate of at least about 10 lpm to a maximum of about 100 lpm. In some cases, the air supply unit may supply oxygen at a flow rate of at least about 100 lpm to a maximum of about 1000 lpm.

The air supply unit may supply oxygen to one or more combustors at various pressures. In some cases, the air supply unit may supply oxygen at a pressure of at least about 0.1 bar (gauge) to a maximum of about 20 bar (gauge).

In some cases, the air intake unit may include a fan or blower, as shown in FIG. 37A. In some cases, the air intake unit may include a compressor for supplying pressurized air from the atmosphere, as shown in FIG. 37B. In some cases, the air intake unit may include a turbine, as shown in FIG. 37B. In some cases, the air intake unit may include a turbocharger unit, as shown in FIG. 37B. In some cases, the air intake unit may include a compression cylinder. In such cases, the air intake unit may be configured to supply pressurized air from the cylinder to one or more combustors. In some cases, the air intake unit may include a venturi restriction. The venturi restriction may be used to create a pressure differential between the venturi restriction and another area of the air intake unit. The pressure differential may be used to draw air from the atmosphere into the venturi restriction.

In some cases, the combustor or combustors may comprise atmospheric combustors, as shown in FIG. 37C. In some cases, the atmospheric combustors may be configured to receive a supply of air or oxygen from a compression cylinder or a fan blower.

In some cases, one or more of the combustors may comprise naturally aspirated combustors. In some cases, the naturally aspirated combustors may be configured to receive a supply of air or oxygen from the surrounding environment, in part due to a vacuum induced within the combustor.

In some cases, the one or more combustors may comprise a pressurized combustor. In some cases, the pressurized combustor may be configured to receive a supply of air or oxygen from a compressor coupled to the turbine. In some cases, the turbine may be driven by one or more exhaust gases from the pressurized combustor.

As described elsewhere herein, the system may include one or more combustors. In some cases, the one or more combustors may be at least partially embedded within the reactor, as shown in FIGS. 38A-38B, 39, 40A-40D, and 42. In some cases, the one or more combustors may be configured to generate thermal energy to heat the reactor in different regions to promote decomposition of the ammonia, as shown in FIG. 42. Various portions of the one or more combustors may be embedded within the reactor. The one or more combustors may be embedded in different regions of the reactor such that different regions within the reactor may be heated separately and/or individually by the one or more combustors.

In some cases, the combustor or combustors can be configured to combust an air-fuel mixture that can be at least partially premixed upstream of the combustion zone, as shown in FIG. 38A. In some cases, premixing the air-fuel mixture allows for more complete combustion of the mixture in the combustion zone.

In some cases, one or more combustors may be configured to combust a mixture of air and fuel, as shown in FIG. 38B, and the air and fuel may be mixed at or near the combustion zone.

The fuel may be provided from one or more of the various components disclosed herein. In some cases, the fuel may include a reactor outlet stream. In some cases, the fuel may include a filtered reactor outlet stream. In some cases, the fuel may include a fuel cell outlet stream. In some cases, the fuel may include an ammonia stream from an ammonia storage tank. In some cases, the fuel may include hydrogen, nitrogen, and ammonia.

In some cases, the combustor or combustors may include one or more air-fuel contact zones configured to mix the hydrogen-containing stream with the oxygen-containing stream to promote combustion. FIG. 39 shows a diagram of an embodiment of a system with two air-fuel contact zones having one combustor. The two air-fuel contact zones may be located a predetermined distance upstream from the combustion zone. In some cases, the two air-fuel contact zones may include an auxiliary contact zone and a main contact zone. In some cases, the auxiliary contact zone and the main contact zone may be separated by a predetermined distance. In some cases, the predetermined distance may be at least about 1 mm to about 1 meter. In some cases, the predetermined distance may be at least about 1 cm to about 20 cm.

The combustor or combustors may include any number of combustion zones at various locations within the reactor. In some cases, the combustor or combustors may include 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 combustion zones.

The combustor or combustors may include any number of air-fuel contact zones at various locations within the reactor. In some cases, the combustor or combustors may include 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 air-fuel contact zones.

The combustor or combustors may include any number of air-fuel premix zones at various locations within the reactor. In some cases, the combustor or combustors may include 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 air-fuel premix zones.

In some cases, the hydrogen and nitrogen supply tubes and the combustor end may be separated by various distances. Figures 40A-40D show diagrams of an embodiment of a system with a combustor configured for combustion inside a reactor. Figure 40C shows several dimensions of a system with a combustor configured for combustion inside a reactor, including the distance between the air supply tube and the reactor end (4001), the distance between the _H2 / _N2 mixture supply tube and the reactor end (4002), the combustor insertion length into the reactor (4003), and the reactor length (4004). Figure 40D shows a photograph of an embodiment of a system with a combustor configured for combustion inside a reactor.

Experiments were conducted to evaluate system performance while varying the _NH3 flow rate and the location of the hydrogen and nitrogen mixture (1:1 volume ratio) and air supply tubes relative to the combustor end configured for combustion. The results of these experiments are shown in Figures 41A-41B. Improvements in reactor and combustor efficiency were observed by adjusting the location of the hydrogen and nitrogen mixture and air supply tubes relative to the combustor end. Figure 41A shows the reactor thermal reforming efficiency as a function of ammonia flow rate, and Figure 41B shows the combustor efficiency as a function of ammonia flow rate. In this example, the reactor thermal reforming efficiency is defined as (chemical energy of hydrogen produced)/(chemical energy of ammonia input + thermal energy input), i.e., the lower heating value of hydrogen produced relative to the sum of the lower heating value of ammonia input and the thermal energy input. In this example, the thermal energy input consists of the heat of reaction and heat losses. In this example, the combustion efficiency is defined as (hydrogen enthalpy of combustion - enthalpy of combustor exit flow)/(hydrogen enthalpy of combustion). For example, 2 cm air - 12 cm _H2 / _{N2 -} 30 cm insertion length indicates a 2 cm distance between the air supply tube and the combustor end (i.e., 4001 in FIG. 40C), a 12 cm distance between the hydrogen and nitrogen mixture supply tube and the combustor end (i.e., 4002 in FIG. 40C), and a 30 cm combustor insertion length inside the reactor (the combustor length is approximately 30 cm from the end to the exhaust outlet, therefore an insertion length of 30 cm refers to full insertion, i.e., 4003 in FIG. 40C).

In some cases, the one or more combustors may comprise two or more combustors configured to heat different regions within the reactor. The different regions may correspond to separate combustion zones. FIG. 42 shows a diagram of an embodiment of a system comprising two combustors. The two combustors may be cylindrical and may be embedded concentrically within the reactor, which may be cylindrical. The two combustors may be diametrically opposed with a separation distance between the opposing faces of the combustors. The combustors may be configured to heat at least two different regions within the reactor separately or independently.

The air and fuel may be mixed and burned at various distances away from the combustor end. Figures 43-45 each show simulation results illustrating the effect of air and fuel mixing and combustion at various distances. In each simulation, a cylindrical tube is embedded concentrically in a cylindrical combustor. Combustion occurs at the air-fuel mixing location, and the heated flow is redirected at the end of the combustor and transported in a direction opposite to the air/fuel feed direction. Because fuel and air mixing is required for complete combustion, not all of the hydrogen is burned immediately at the air-fuel mixing location, but the flame extends through the combustor with the mixture flow. This heat can then be transferred to the outermost wall of the combustor and the external environment (e.g., reactor). The air-fuel contact and combustion zone may be located at a predetermined distance from the combustor end, for example, about 4 cm in Figure 43, about 2 cm in Figure 44, about 6 cm in Figure 45A, and about 8 cm in Figure 45B. In each simulation, the flow rate of fuel (H ₂ /N ₂ , 1:1 volumetric mixture) was 10 lpm and the air flow rate was 20 lpm. The temperature profile in the system was calculated under steady state assumptions for each simulation. In each configuration of Figures 43-45, the temperature profile changes with respect to the maximum temperature in the combustor, which may affect the stability of materials in the system. In some cases, the temperature profile also changes with respect to the maximum temperature gradient in the reactor, which may induce different levels of stress and/or oxidation in materials in the system. In some cases, the temperature profile also changes with respect to the distribution of temperatures in various regions in the combustor, which may affect the performance of the reactor.

46A-46B show simulation results showing the effect of air and fuel premixing/precombustion holes at various distances, respectively. In the premixing/precombustion holes, fuel and air can be partially mixed and combusted. This mechanism can distribute heat more evenly throughout the combustor and reduce local hot spot temperatures compared to cases without premixing/precombustion holes. For example, FIG. 46A shows a temperature distribution where the case without premixing/precombustion holes has the highest local hot spot temperature compared to cases with holes (e.g., 1, 2, and 3 holes). Thus, the premixing/precombustion holes may affect the stability of materials in the system. The maximum temperature gradients in the reactor also vary between cases, and different maximum temperature gradients may induce different levels of stress and oxidation in the materials of the system. In some cases, the temperature profile also varies in temperature distribution in different regions of the combustor, which may affect the performance of the reactor.

The combustor(s) may each be of various shapes and sizes. In some cases, the combustor(s) may be cylindrical or circular in cross-section, as shown in Figures 40A-40D and 43-45B. In some cases, the combustor(s) may be rectangular in shape or cross-section. In some cases, the combustor(s) may be concentric with the reactor.

In some cases, the combustor(s) may be made of a high temperature refractory material. The high temperature refractory material may be resistant to thermal shock, chemically inert, have a thermal conductivity in a particular range, or have a coefficient of thermal expansion in a particular range. In some cases, the high temperature refractory material may be configured to improve the stability of the combustor. In some cases, the refractory material may include steel, tungsten carbide, alumina, magnesia, silica, lime, metal oxides, _{tungsten, molybdenum, or any combination thereof. In some cases, the refractory material may include at least one of metal oxides, e.g., Al2O3 , SiO2} , _ZrO2 , _VO2 ; Ta; alloys of Ni, Al, Mo, Cr, Si, or any combination thereof. In some cases, the refractory material may include at least one of steel, tungsten, molybdenum, tungsten carbide, or any combination thereof. In some cases, the refractory material may be coated on one or more surfaces of the one or more combustors. The refractory material may be coated on or near the combustion zone, on or near the surfaces that contact the reactor, or on any other surface of the reactor. In some cases, the refractory material may be reinforced with a structural metal. In some cases, the refractory material may be held and/or covered by a structural metal such that the structural metal supports the refractory material against one or more fractures.

Figures 47-48 each show a schematic of a combustor and reactor design according to one or more embodiments of the present disclosure. In some cases, the combustor and reactor may be sized such that the combustor can fit within the reactor.

The reactor can be configured to receive ammonia from the tank and process the ammonia (as described elsewhere herein) to produce hydrogen and/or nitrogen. Processing the ammonia can include cracking, decomposing, or dissociating the ammonia to obtain hydrogen and/or nitrogen. The hydrogen and/or nitrogen may flow out of the reactor to one or more adsorber bodies before the mixture of hydrogen and nitrogen is directed to one or more fuel cells. The adsorber bodies can be used to remove trace ammonia and/or nitrogen from the reactor outlet stream. The one or more fuel cells can be configured to generate electrical energy from the hydrogen/nitrogen mixture. In some cases, the one or more fuel cells may have an exhaust stream that includes unconverted or unprocessed hydrogen and/or nitrogen.

In some cases, the reactor may include a combustor disposed at least partially within the reactor. The combustor may be configured to receive air through a first inlet and a mixture of hydrogen and nitrogen from the one or more fuel cells through a second inlet. The combustor may include an interior region or volume for combusting the mixture of hydrogen and nitrogen with the supplied air to heat the reactor for further ammonia decomposition.

The combustor may be of various sizes and various cross-sectional areas. In some cases, a combustor with a larger cross-sectional area, e.g., FIG. 47, may generate a lower pressure drop than a combustor with a smaller cross-sectional area, e.g., FIG. 48. In some cases, the combustor may have a cross-sectional area between 5 cm ² and 25 cm ^2. In some cases, the combustor may have a cross-sectional area between 25 cm ² and 200 cm ^2. In some cases, the combustor may have a cross-sectional area between 10 cm ² and 500 cm ^2. In some cases, the combustor may have a cross-sectional area between 100 cm ² and 5000 cm ² .

A combustor may have one or more inlets and one or more outlets at various locations on the combustor. In some cases, a combustor may have one or more inlets and one or more outlets on the same side of the combustor. In some cases, a combustor may have one or more inlets and one or more outlets on different sides of the combustor.

The combustor may have one or more inlets and one or more outlets oriented in various directions on the combustor. In some cases, the combustor may have one or more inlets and one or more outlets oriented in the same direction. In some cases, the combustor may have one or more inlets and one or more outlets oriented in perpendicular directions. In some cases, the combustor may have one or more inlets and one or more outlets oriented in a direction along the longest axis of the combustor. In some cases, the combustor may have one or more inlets and one or more outlets oriented perpendicular to the longest axis of the combustor. In some cases, the combustor may have one or more inlets and one or more outlets oriented in a single direction. In some cases, the combustor may have one or more inlets and one or more outlets oriented in at least two different directions. In some cases, the combustor may have one or more inlets and one or more outlets oriented in at least three different directions.

The systems disclosed herein may include mobile systems having a variety of volumes. In some cases, the mobile system may have a volume of up to about 10 m3. In some cases, the mobile system may have a volume of up to about ^{2 m3} . In some cases, the mobile system may have a volume of up to about 1 ^m3 . In some cases, the mobile system may have a volume of up to about 0.5 ^m3 . In some cases, the mobile system may have a volume of up to about 0.25 ^m3 . In some cases, the mobile system may have a volume of up to about 0.1 ^m3 . In some cases, the mobile system may have a volume of up to about 0.05 ^m3 . In some cases, the mobile system may have a volume of up to about 0.01 ^m3 .

In some embodiments, the system may include multiple reactors connected in parallel. In some cases, the multiple reactors may include one or more combustion reactors and one or more electric reactors (e.g., four or more electric reactors). In some cases, a heat exchanger may be used to transfer heat and/or vaporize the incoming ammonia stream from one or more outlet streams from one or more combustion or electric reactors. In some cases, after the heat exchanger, the preheated ammonia stream may be evenly distributed among each reactor in the multiple reactors. In some cases, the flow distribution in one or more reactors in the multiple reactors may be improved using a pressure drop element, such as a restrictive orifice. In some cases, the distributed preheated and/or vaporized ammonia gas may be preheated by passing through a fired heater before entering the electric or combustion reactor. In some cases, the electric reactor outlet stream may be fed into the combustion reactor. In some cases, the combustion reactor outlet stream may be fed into the electric reactor. In some cases, one or more combustion reactor outlet streams may be combined and fed into a heat exchanger. In some cases, the electric reactor outlet stream or streams may be combined and input to a heat exchanger. In some cases, the cooled product gas from the heat exchanger may pass through another heat exchanger to be further cooled toward ambient temperature. In some cases, an adsorber may be used to filter unconverted ammonia from the product gas from the combustion reactor, the electric reactor, the heat exchanger, or any combination thereof. In some cases, the filtered _N2 / _H2 mixed product stream may be fed to a fuel cell. In some cases, a hydrogen separation unit (e.g., a pressure swing adsorption (PSA) system or a hydrogen permeable membrane system) may be used to make the product gas have a higher concentration of hydrogen compared to the gas input stream to the separation unit. In some cases, the unconverted hydrogen from the fuel cell or fuel cells may be distributed evenly through each combustion reactor in the multiple reactors and used as a combustion fuel. In some cases, the hydrogen and nitrogen-containing exhaust stream from the hydrogen separation unit or units may be distributed evenly through each combustion reactor in the multiple reactors and used as a combustion fuel. In some cases, the air supply unit or units may supply air to the combustion reactor or reactors in the multiple reactors. In some cases, the system may operate using a self-sustaining autothermal reforming process. In some cases, flame flares may be observed near the exhaust port of the combustion reactor(s) depending on the air flow rate to the combustion reactor(s), hydrogen utilization rate, and/or hydrogen consumption rate of the fuel cell(s). In some cases, the hydrogen combustion required to sustain autothermal reforming may be about 25-45% of the hydrogen produced from ammonia cracking. In some cases, the hydrogen combustion required to sustain autothermal reforming may be at least about 10, 20, 30, 40, 50, 60, 70, 80, or 90% of the hydrogen produced from ammonia cracking. In some cases, the hydrogen combustion required to sustain autothermal reforming may be up to about 10, 20, 30, 40, 50, 60, 70, 80, or 90% of the hydrogen produced from ammonia cracking. In some cases, the remaining hydrogen (e.g., 55-75%) of the hydrogen produced may be consumed by the fuel cell(s) to generate power or may be supplied as hydrogen gas on demand. In some cases, at least about 10, 20, 30, 40, 50, 60, 70, 80, or 90% of the hydrogen produced from ammonia cracking may be consumed by one or more fuel cells to generate electricity or supplied as hydrogen gas on demand. In some cases, up to about 10, 20, 30, 40, 50, 60, 70, 80, or 90% of the hydrogen produced from ammonia cracking may be consumed by one or more fuel cells to generate electricity or supplied as hydrogen gas on demand. In some cases, a higher percentage of the hydrogen produced from ammonia cracking may be consumed during start-up operation or during a heat-up phase.

FIG. 74 illustrates a combustion burner head design according to one or more embodiments of the present disclosure. In some cases, the hydrogen-nitrogen mixture fuel may be supplied through a fuel inlet and air may be supplied to an air inlet. In some cases, the hydrogen-nitrogen mixture fuel may be distributed to one or more outlets/slots (e.g., a total of four outlets/slots). In some cases, at these outlets, the fuel and air may be injected substantially perpendicular to the direction of flow (e.g., at about 60 to about 120 degrees). In some cases, the injection of the fuel and air may form a rapidly mixed (e.g., swirling) combustion. In some cases, the fuel and air lines for supplying the fuel and air may be sized to have a relatively low pressure drop (e.g., less than about 1 bar). In some cases, the fuel and air lines for supplying the fuel and air may be sized to maintain a high injection velocity. In some cases, the high injection velocity may be high enough to reduce or prevent backflow and/or flashback, and may improve mixing compared to lower injection velocities. In some cases, a plenum-style reservoir may be used to further minimize the pressure drop. In some cases, an insertable design may be used to facilitate maintenance and replacement. In some cases, the burner head may be inserted into the combustion reactor or may be permanently attached. In some cases, the burner head may include one or more fuel or air injection slots. In some cases, the burner head may include one or more insertable seals for insertion into the combustion reactor. In some cases, the burner head may have an air or fuel injection slot cross-sectional area of ^1-50 mm2. In some cases, the burner head may have an air or fuel injection slot cross-sectional area of 1-20 mm2. In some cases, the burner head may have a fuel injection slot cross-sectional area ^of 4-15 ^mm2 for fuel input. In some cases, the burner head may have an air injection slot cross-sectional area of 5-18 ^mm2 for air input. In some cases, the burner head may have a fuel injection slot cross-sectional area of 6-12 ^mm2 for fuel input. In some cases, the burner head may have an air injection slot cross-sectional area of 7-15 ^mm2 for air input. In some cases, the fuel and air velocities at the injection slot or slots may be at various speeds. In some cases, the fuel velocity may be between 10 and 200 m/s. In some cases, the fuel velocity may be between 50 and 130 m/s. In some cases, the air velocity may be between 30 and 250 m/s. In some cases, the air velocity may be between 50 and 200 m/s. In some cases, the air velocity may be between 70 and 130 m/s.

Ammonia reformer durability testing was performed with the burner head installed at high speed for over 10 consecutive on/off temperature cycles. Throughout the 10+ cycles, ammonia reformer performance remained constant with an ammonia conversion efficiency of over 99% and a hydrogen consumption rate of approximately 30-40% (relative to the hydrogen produced by ammonia decomposition) without the use of a heat exchanger or recuperator.

75A-75B show a burner head design according to one or more embodiments of the present disclosure. In some cases, the burner head may include an optional ammonia preheat line. In some cases, the burner head may include one or more slots for inputting fuel and/or air. In some cases, the burner head may include at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 slots for inputting fuel and/or air. In some cases, the burner head may include up to about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 slots for inputting fuel and/or air. In some cases, the burner head may include an even number (e.g., 2, 4, 6, 8, 10, . . .) of slots for inputting fuel and/or air. In some cases, the burner head can be configured to provide a swirling flow of gas when fuel and/or air is input through one or more slots. In some cases, the burner head may be at least partially enclosed within an insulating material. In some cases, at least one of the ammonia, air, and combustion fuel may be preheated by exchanging heat with the combustion product gases through a concentric flow tube disposed inside the one or more combustion tubes. In some cases, the pressure drop of the air and/or combustion fuel flow through the burner head is less than about 2 bar. In some cases, the pressure drop of the air and/or combustion fuel flow through the burner head is less than about 1 bar. In some cases, the pressure drop of the air and/or combustion fuel flow through the burner head is less than about 0.5 bar. The air and/or combustion fuel flow through the burner head is less than about 5, 4, 3, 2, 1, 0.5, 0.4, 0.3, 0.2, or 0.1 bar. In some cases, the pressure drop of the air and/or combustion fuel flow through the burner head is greater than about 0.5 bar, and the air and/or combustion fuel flow through the burner head is less than about 5, 4, 3, 2, 1, 0.5, 0.4, 0.3, 0.2, or 0.1 bar.

FIGS. 76A-76B show burner head designs according to one or more embodiments of the present disclosure. In some cases, the burner head can be configured to be inserted into the combustion reactor. In some cases, the combustion reactor may be configured to be inserted into the burner head. In some cases, the burner head and the elongated combustion reactor may be coupled at an end of the elongated combustion reactor.

FIG. 77 shows a fluid simulation in a combustion tube with a burner head according to one or more embodiments of the present disclosure. A reacting flow simulation was performed to study the combustion and reaction characteristics without ammonia reforming. Heat transfer boundary conditions of 900K and 400W/ ^m2 -K were used. If ammonia reforming is considered in the simulation, the process variables, velocity field, and temperature field may change. The flow field lines are shown without any solid physical boundaries.

FIG. 78 illustrates a fluid simulation in a combustion tube with a burner head according to one or more embodiments of the present disclosure. The (i) slot size or cross-sectional area, (ii) injection direction or angle, (iii) burner insertion depth, or (iv) gap between the slot and the combustion tube of the fuel and/or air injection can be optimized to change the combustion characteristics. FIG. 79 illustrates a fluid simulation in a combustion tube with a burner head according to one or more embodiments of the present disclosure. In some cases, the burner head may include one or more fuel inlets or air inlets configured to provide a swirl flow in the combustion reactor. In some cases, the one or more fuel inlets or air inlets may be arranged with substantially radial symmetry on the burner head.

Aircraft vehicles

Figure 49 shows a schematic of an example system architecture for an ammonia processing system that can be mounted to and adapted for use with an air vehicle. The air vehicle can include an unmanned aerial vehicle (UAV), a drone, a rotorcraft, a fixed wing, a flap wing, a helicopter, an airplane, or a jet. Table 1 describes each graphical element shown in Figure 49.

In some cases, the system may include one or more reactors (R) configured to partially or completely crack ammonia provided to the one or more reactors to obtain hydrogen, nitrogen, and/or ammonia. In some cases, the system may include one or more fuel cells (FC) in fluid communication with the one or more reactors. In some cases, the one or more fuel cells are configured to receive and process hydrogen from the one or more reactors to generate electrical energy. In some cases, the one or more reactors and the one or more fuel cells can be configured to be on or mounted to an air vehicle. In some cases, the one or more fuel cells are in electrical communication with one or more motors or drives of the air vehicle to drive the one or more motors or drives of the air vehicle. The drives may include, for example, one or more rotors or propellers.

In some cases, the reactor(s) may be configured to be mounted to an air vehicle. In some cases, the fuel cell(s) may be configured to be mounted to an air vehicle. In some cases, the reactor(s) and the fuel cell(s) may be configured to be mounted to an air vehicle. In some cases, the motor(s) or drive(s) may be configured to be mounted to an air vehicle.

In another aspect, the present disclosure provides an ammonia power pack system that can be mounted on an air vehicle to power one or more motors or drives of the air vehicle. In some cases, the ammonia power pack system may have an optimized physical layout and/or packaging. FIG. 50 shows a digital rendering of an ammonia power pack system according to one or more embodiments of the present disclosure. This image shows an embodiment in which multiple fuel cells, an ammonia tank, and one or more adsorbents are mounted on a first stage and one or more ammonia reactors are mounted on a second stage above the first stage. The aforementioned components and their assembly may be designed to have a total system weight and volume of up to about 25 kilograms (kg). In some cases, the total system weight, including the weight of a full tank of ammonia, may be about 24 kg to about 25 kg. In some cases, the total system weight may be about 20 kg to about 30 kg. In some cases, the total system weight may be about 10 kg to about 40 kg. In some cases, the total system weight may be up to about 25 kg. In some cases, the total system weight may be up to about 100 kg. In some cases, the total system volume may be about 35 L to about 37 L. The total volume may be interpreted as the volume of fluid displaced when the object is fully immersed in the fluid. The total volume may be interpreted as the sum of the volumes of the individual components and/or hardware of the system. In some cases, the total volume of the system may be about 30 L to about 40 L. In some cases, the total volume of the system may be about 20 L to about 50 L. In some cases, the total volume of the system may be up to about 40 L. In some cases, the total volume of the system may be up to about 200 L. In some cases, the total volume of the system may be from about 200 L to about 1000 L.

In some cases, the components can be arranged to allow easy access to the ammonia tank so that a user can easily replace the tank with a full or partially filled tank or fill the tank with ammonia as desired. The components may also be arranged symmetrically so that the weight distribution of the system is balanced when mounted on an air vehicle. FIG. 51 shows a digital rendering of an ammonia power pack system mounted on an air vehicle according to one or more embodiments of the present disclosure.

Figure 52 shows a photograph of the air vehicle fitted with the ammonia power pack system. Flight tests were conducted on the air system to measure flight time and power output of the ammonia power pack system. Figure 53 shows a photograph of the air vehicle in flight. The vehicle specifications are shown in Table 2 below.

Figure 54 shows the results of testing the aircraft system for an 800 second flight. The total power required of the system remained substantially stable over time at approximately 3600 watts. The power output of the battery and ammonia power pack systems was adjusted such that the battery contribution decreased over time while the total power output remained substantially the same.

In some cases, the ammonia processing and ammonia power pack system can be sized to meet 100% of the power needs of the load (e.g., an air vehicle).In some cases, the ammonia processing and ammonia power pack system can be sized to meet 100% of the power needs of the load (e.g., an air vehicle) and generate additional energy to be able to charge an on-board auxiliary battery.

In some cases, the ammonia processing and ammonia power pack system may have an energy density of at least about 650 watt-hours per kilogram (Wh/kg). In some cases, the ammonia processing and ammonia power pack system may have an energy density of at least about 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 2000, 3000, 4000, 5000, or 6000 watt-hours per kilogram. In some cases, the ammonia processing and ammonia power pack system may have an energy density of up to about 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 2000, 3000, 4000, 5000, or 6000 watt-hours per kilogram.

In some cases, the ammonia processing and ammonia power pack system may have an energy density of at least about 400 watt-hours per liter (Wh/L). In some cases, the ammonia processing and ammonia power pack system may have an energy density of at least about 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 2000, 3000, or 4000 watt-hours per liter. In some cases, the ammonia processing and ammonia power pack system may have an energy density of up to about 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 2000, 3000, or 4000 watt-hours per liter.

81A-81B show the voltage vs. current and power vs. current, respectively, of an integrated power pack with a fuel cell. The fuel cell generated over 20 kilowatts of electricity using the product gas from a system with three electric reactors and three combustion reactors. In some embodiments, the system may include one or more pairs of electric reactor-combustion reactor modules. In some embodiments, a pair of electric reactor-combustion reactor modules may include an electric reactor and a combustion reactor connected in series flow. In some embodiments, at least two pairs of electric reactor-combustion reactor modules may be connected in parallel flow. Pure hydrogen and synthetic hydrogen/nitrogen mixture experimental results performed at steady state are also shown for comparison. In the operation of the integrated reformed ammonia fuel cell, a small voltage drop may occur due to cold start of the fuel cell compared to the pure _H2 and synthetic mixture operation. Three different runs were performed using reformed ammonia product gas. The fuel cell outlet stream was fed to a fired heater. The system maintained autothermal reforming.

In some cases, the energy density of the system can be defined as the ratio between the amount of available energy of the ammonia stored in the system. In some cases, the energy density of the system can be defined as the ratio between the amount of available energy of the ammonia stored in the system that can be converted into usable electricity. In some cases, the energy density of the system can be defined as the ratio between the amount of available energy of the ammonia stored in the system that can be converted into usable hydrogen energy. In some cases, the system may refer to one or more ammonia tanks and one or more reactors. In some cases, the system may refer to one or more ammonia tanks, one or more reactors, and one or more fuel cells. In some cases, the system may refer to one or more ammonia tanks, one or more reactors, one or more fuel cells, and various other components (e.g., combustors, adsorber, heat exchangers, electrical components, or any other components disclosed herein) that are coupled thereto.

Each of the one or more reactors may be configured to crack a variety of amounts of ammonia per unit time. The amount of ammonia cracked may be based at least in part on the size of the air vehicle, the weight of the air vehicle, whether the air vehicle is moving or stationary, or any combination thereof. In some cases, each of the one or more reactors may be configured to crack at least about 30 liters/min of ammonia (e.g., at about standard temperature and pressure). In some cases, each of the one or more reactors may be configured to crack about 30-100 liters/min of ammonia (e.g., at about standard temperature and pressure). In some cases, each of the one or more reactors may be configured to crack about 100-300 liters/min of ammonia (e.g., at about standard temperature and pressure). In some cases, each of the one or more reactors may be configured to crack up to about 1000 liters/min of ammonia (e.g., at about standard temperature and pressure). In some cases, each of the one or more reactors may be configured to crack up to about 5000 liters/min of ammonia (e.g., at about standard temperature and pressure).

The reactor or reactors may be mounted on any side of the air vehicle or on one or more sides of the air vehicle, for example, the forward, aft, lateral, top, or bottom of the air vehicle. As used herein, terms indicating orientation or direction (e.g., forward, aft, lateral, top, bottom) may be relative to an axis of the longest dimension of the body and/or to gravity or the center of gravity. For example, in an air vehicle, the orientation or direction may be relative to the longest dimension of the air vehicle and/or to gravity. In another example, in an air vehicle with a body that is radially symmetric such that the air vehicle has multiple axes of the longest dimension of the body, the orientation or direction may be relative to any one of the axes.

In some cases, the reactor(s) may be mounted between two adjacent sides of the aviation vehicle. In some cases, the reactor(s) may all be mounted on one side. In some cases, the reactor(s) may be mounted on multiple sides. The reactor(s) may be oriented to receive a flow of ammonia from a tank located in front of the aviation vehicle, in the rear of the aviation vehicle, or from a side of the aviation vehicle. The reactor(s) may be oriented to discharge a flow of hydrogen, nitrogen, and/or trace ammonia to one or more adsorbers, heat exchangers, and/or fuel cells located on the front of the aviation vehicle, in the rear of the aviation vehicle, on a side of the aviation vehicle, on the bottom of the aviation vehicle, or on the top of the aviation vehicle. The reactor(s) may be mounted on another component mounted on the aviation vehicle. In some cases, the reactor(s) may include two or more start-up reactors and two or more main reactors. In some cases, the ammonia tank may be in fluid communication with one or more heat exchangers to vaporize and/or heat the ammonia. In some cases, the vaporized ammonia gas may be fed to one or more reactors.

The one or more fuel cells may be mounted on any side of the aviation vehicle, or on one or more sides of the aviation vehicle, such as the front, rear, side, top, or bottom of the vehicle. In some cases, the one or more fuel cells may be mounted between two adjacent sides of the aviation vehicle. In some cases, the one or more fuel cells may be mounted all on one side. In some cases, the one or more fuel cells may be mounted on multiple sides. In some cases, the one or more fuel cells may be oriented to receive a stream comprising hydrogen and/or nitrogen from one or more reactors or one or more adsorbents located on the front of the aviation vehicle, the rear of the aviation vehicle, on the side of the aviation vehicle, on the bottom of the aviation vehicle, or on the top of the aviation vehicle. The one or more fuel cells may be oriented to discharge a stream comprising hydrogen and/or nitrogen towards one or more reactors or one or more combustors located on the front of the aviation vehicle, the rear of the aviation vehicle, on the side of the aviation vehicle, on the bottom of the aviation vehicle, or on the top of the aviation vehicle. The one or more fuel cells may be mounted on another component mounted on the aviation vehicle.

The motor or drives may be mounted on any side of the air vehicle, or on one or more sides of the air vehicle, e.g., the front, rear, side, top, or bottom of the vehicle. In some cases, the motor or drives may be mounted between two adjacent sides of the air vehicle. In some cases, the motor or drives may all be mounted on one side. In some cases, the motor or drives may be mounted on multiple sides. The motor or drives may be oriented to exert a force on the air vehicle in any direction, e.g., forward, rear, lateral, vertical, radial, or any combination thereof. The motor or drives may be oriented to move the air vehicle in any direction, e.g., forward, rear, lateral, vertical, radial, or any combination thereof. The motor or drives may be mounted on another component that is mounted on the air vehicle.

In some cases, the system may further include one or more adsorbents in fluid communication with the one or more reactors. In some cases, the one or more adsorbents may be configured to process an outlet stream from the one or more reactors to filter or remove ammonia from the outlet stream. In some cases, the one or more adsorbents may be configured to process an outlet stream from the one or more reactors to filter or remove nitrogen from the outlet stream. In some cases, the outlet stream includes hydrogen and/or nitrogen. In some cases, the adsorbents may be in fluid communication with one or more fuel cells. In some cases, the adsorbents are configured to direct hydrogen and/or nitrogen to the one or more fuel cells after filtering or removing ammonia from the outlet stream of the one or more reactors.

The one or more adsorbents may be mounted on any side of the aircraft vehicle or on one or more sides of the aircraft vehicle, for example, the front, rear, side, top, or bottom of the vehicle. In some cases, the one or more adsorbents may be mounted between two adjacent sides of the aircraft vehicle. In some cases, the one or more adsorbents may all be mounted on one side. In some cases, the one or more adsorbents may be mounted on multiple sides. The one or more adsorbents may be oriented to receive a stream comprising hydrogen, ammonia, nitrogen, or any combination thereof from one or more reactors, one or more combustors, or one or more fuel cells disposed on the front of the aircraft vehicle, the rear of the aircraft vehicle, on the side of the aircraft vehicle, on the bottom of the aircraft vehicle, or on the top of the aircraft vehicle. The one or more adsorbents may be oriented to discharge a stream comprising hydrogen and/or nitrogen to both one or more fuel cells or one or more combustors disposed on the front of the aircraft vehicle, the rear of the aircraft vehicle, on the side of the aircraft vehicle, on the bottom of the aircraft vehicle, or on the top of the aircraft vehicle. The one or more adsorbents may be mounted on another component mounted on the aircraft vehicle.

In some cases, the system may further include one or more combustors in fluid communication with the one or more fuel cells. In some cases, the one or more combustors are configured to combust an outlet stream from the one or more fuel cells to heat the one or more reactors. In some cases, the one or more combustors may be configured to combust a stream from an ammonia tank, an outlet stream from the one or more reactors, an outlet stream from the one or more fuel cells, or any combination thereof.

In some cases, the system may further include a selective catalytic reduction (SCR) system configured to remove nitrous oxide (NOx) from the one or more flue gas streams. In some cases, the SCR system receives ammonia from one or more ammonia tanks.

The combustor(s) may be mounted on any side of the air vehicle or on one or more sides of the air vehicle, for example, on the front, rear, side, top, or bottom of the vehicle. In some cases, the combustor(s) may be mounted between two adjacent sides of the air vehicle. In some cases, the combustor(s) may all be mounted on one side. In some cases, the combustor(s) may be mounted on multiple sides. The combustor(s) may be oriented to receive a flow comprising hydrogen and/or nitrogen from one or more reactors, one or more adsorbers, or one or more fuel cells disposed on the front of the air vehicle, on the rear of the air vehicle, on a side of the air vehicle, on the bottom of the air vehicle, or on the top of the air vehicle. The combustor(s) may be oriented to exhaust a flow comprising combustion by-products to the surrounding environment. The combustor(s) may be mounted on another component mounted on the air vehicle.

In some cases, one or more electric heaters may be used inside one or more reactors. In some cases, one or more electric heaters may be used in addition to one or more combustors in one or more reactors.

In some cases, the system may further include one or more fuel storage tanks mounted on the aircraft vehicle. In some cases, the fuel storage tanks may be in fluid communication with the one or more reactors to supply ammonia to the one or more reactors for cracking or decomposing the ammonia. In some cases, the one or more fuel storage tanks may be in fluid communication with one or more heat exchangers to vaporize and heat the ammonia. In some cases, the vaporized ammonia gas may be supplied to the one or more reactors to crack or decompose the ammonia.

The one or more fuel storage tanks may be mounted on any side of the aircraft vehicle or on one or more sides of the aircraft vehicle, such as the front, rear, side, top, or bottom of the vehicle. In some cases, the one or more fuel storage tanks may be mounted between two adjacent sides of the aircraft vehicle. In some cases, the one or more fuel storage tanks may all be mounted on one side. In some cases, the one or more storage tanks may be mounted on multiple sides. In some cases, the one or more fuel storage tanks may be oriented to discharge the ammonia-containing stream toward one or more reactors located on the front of the aircraft vehicle, the rear of the aircraft vehicle, on the side of the aircraft vehicle, on the bottom of the aircraft vehicle, or on the top of the aircraft vehicle. In some cases, the one or more fuel storage tanks may be oriented to discharge the ammonia-containing stream toward one or more heat exchangers located on the front of the aircraft vehicle, the rear of the aircraft vehicle, on the side of the aircraft vehicle, on the bottom of the aircraft vehicle, or on the top of the aircraft vehicle. The one or more fuel storage tanks may be mounted on another component mounted on the aircraft vehicle.

In some cases, the system may further include one or more heat exchangers for cooling the outlet stream of the one or more reactors. In some cases, the one or more heat exchangers are in thermal communication with the outlet stream from the one or more fuel cells to cool the heat exchanger and/or the outlet stream from the one or more reactors. The outlet stream from the one or more fuel cells may include air or oxygen.

The one or more heat exchangers may be mounted on any side of the aviation vehicle, or on one or more sides of the aviation vehicle, such as the front, rear, side, top, or bottom of the vehicle. In some cases, the one or more heat exchangers may be mounted between two adjacent sides of the aviation vehicle. In some cases, the one or more heat exchangers may all be mounted on one side. In some cases, the one or more heat exchangers may be mounted on multiple sides. The one or more heat exchangers may be oriented to receive a stream comprising hydrogen and/or nitrogen from one or more reactors, one or more combustors, one or more fuel cells, or one or more adsorbents mounted on the front of the aviation vehicle, the rear of the aviation vehicle, on a side of the aviation vehicle, on the bottom of the aviation vehicle, or on the top of the aviation vehicle. The one or more heat exchangers can be oriented to discharge a stream containing hydrogen and/or nitrogen toward one or more reactors, one or more combustors, one or more fuel cells, or one or more adsorber mounted on the front of the air vehicle, the rear of the air vehicle, on a side of the air vehicle, on the bottom of the air vehicle, or on the top of the air vehicle. The one or more heat exchangers may be mounted on another component mounted on the air vehicle.

In some cases, the one or more heat exchangers can be oriented to receive an ammonia-containing stream from one or more ammonia storage tanks mounted on the front of the aircraft vehicle, the rear of the aircraft vehicle, on the side of the aircraft vehicle, on the bottom of the aircraft vehicle, or on the top of the aircraft vehicle. The one or more heat exchangers can be oriented to discharge an ammonia-containing stream to one or more reactors and/or one or more combustors mounted on the front of the aircraft vehicle, the rear of the aircraft vehicle, on the side of the aircraft vehicle, on the bottom of the aircraft vehicle, or on the top of the aircraft vehicle. The one or more heat exchangers may be mounted on another component mounted on the aircraft vehicle.

In some cases, the one or more fuel cells may be in communication with an electrical load. In some cases, the electrical load may include one or more motors or drives of the air vehicle. In some cases, the electrical load may be one or more auxiliary batteries. In some cases, the one or more fuel cells may charge the one or more batteries.

In some cases, the one or more fuel cells may be in thermal communication with one or more fuel storage tanks to facilitate the transfer of thermal energy from the fuel cells to the fuel storage tanks to heat the fuel storage tanks for ammonia evaporation. In some cases, the one or more fuel cells may be in thermal communication with one or more air-cooled heat exchangers to facilitate rejection of heat to the surrounding environment. In some cases, the one or more fuel cells may be in thermal communication with one or more heat exchangers to facilitate the transfer of thermal energy from the fuel cells to vaporize one or more liquid or liquid/gas two-phase ammonia streams.

In some cases, the system may further include a controller configured to control a flow of ammonia provided to the one or more reactors based on a desired power output from the one or more fuel cells. In some cases, the desired power output may be based at least in part on a user input for controlling the air vehicle. In some cases, the desired power output may be based at least in part on a power output required to maintain the air vehicle in a stationary position or to move the air vehicle. In some cases, the controller may be configured to shut off one or more ammonia flows.

In some cases, the system may further include a controller operably coupled to one or more valves to control (i) the flow of ammonia to the one or more reactors, or (ii) the flow of hydrogen to the one or more fuel cells. In some cases, the controller may be configured to perform dynamic power control by controlling the operation of the one or more valves. In some cases, the controller may be configured to adjust one or more valves coupled to the ammonia storage tank to maintain or reach a threshold pressure point to increase ammonia flow rate and power output. In some cases, the ammonia flow rate is correlated to the ammonia flow pressure. In some cases, the controller may be configured to adjust one or more valves (e.g., solenoid valves) coupled to the ammonia storage tank to maintain or reach a threshold flow rate.

In some cases, the system may further include a controller and one or more sensors operably coupled to the controller. In some cases, the controller is configured to monitor the temperature of the one or more reactors, the ammonia flow pressure, and/or the electrical output of the one or more fuel cells based on one or more measurements obtained using the one or more sensors. In some cases, the controller may be configured to monitor the flow rate of the one or more ammonia streams using a mass flow meter or mass flow controller.

In some cases, the controller may be configured to increase power to the air supply unit to increase air flow to the combustor or combustors of the reactor or reactors if the temperature of the reactor or reactors drops or falls below a threshold temperature. In some cases, the threshold temperature may be about 600°C. In some cases, the threshold temperature may be between about 550°C and about 650°C. In some cases, the threshold temperature may be between about 450°C and about 700°C. In some cases, the threshold temperature may be about 800°C. In some cases, the threshold temperature may be between about 300°C and about 450°C.

In some cases, the system may further include an auxiliary battery for powering one or more motors or drives of the air vehicle. In some cases, the desired power output may be met with power contributions from the one or more fuel cells and the second power source. In some cases, the flow of ammonia supplied to the one or more reactors may be controlled such that the total amount of power generated by the one or more fuel cells and the second power source meets the desired power output. In some cases, the second power source may include an auxiliary battery.

In some cases, the system may include a start-up reactor. In some cases, the start-up reactor may be configured to crack at least a portion of the ammonia provided to the one or more reactors to produce hydrogen, nitrogen, and/or ammonia. In some cases, the start-up reactor may be in fluid communication with the main reactor and/or the combustor. In some cases, the main reactor is configured to combust at least a portion of an outlet stream from the start-up reactor to heat or preheat the main reactor. In some cases, the outlet stream from the start-up reactor may include hydrogen and at least one of ammonia or nitrogen.

In some cases, the ammonia power pack system may follow a start-up sequence. In some cases, the start-up sequence may include steps for heating the reactor(s). In some cases, the start-up sequence may include steps for heating the start-up reactor. In some cases, the heating of the reactor(s) or the start-up reactor may be performed using an external power source or by burning a fuel. In some cases, the external power source may be a battery (e.g., a chemical battery or a battery). In some cases, the fuel may be hydrogen, gasoline, diesel, methanol, ethanol, biodiesel, propane, butane, or any other type of combustible material. In some cases, the external power source may be electricity from a power grid.

In some cases, the start-up sequence may include providing a stream of ammonia (NH _{3 )} to one or more reactors and/or a start-up reactor for partially or completely cracking the NH ₃ stream using the one or more reactors or the start-up reactor.

In some cases, the start-up sequence may include a step for heating one or more combustors of the primary reactor by combusting an exhaust stream from the start-up reactor. In some cases, the exhaust stream from the start-up reactor may include hydrogen and/or nitrogen. In some cases, the exhaust stream may further include ammonia.

In some cases, the start-up sequence may include steps for modifying (e.g., increasing or decreasing) the _NH3 flow rate to one or more reactors. In some cases, modifying the _NH3 flow rate to one or more reactors modifies the amount of _NH3 converted to produced hydrogen. In some cases, modifying the _NH3 flow rate to one or more reactors may control the amount of hydrogen supplied to one or more fuel cells. In some cases, modifying the _NH3 flow rate to one or more reactors may control (i) the amount of hydrogen produced or the rate at which hydrogen is produced using one or more reactors, and/or (ii) the power output from one or more fuel cells. In some cases, the flow rate may be modified by adjusting the position of a valve between a fully open and a fully closed state. In some cases, the flow rate may be modified using a controller operably coupled to one or more valves.

In some cases, the start-up sequence may include a step for directing a flow containing hydrogen and nitrogen to the adsorber when the reactor or reactors reach a target temperature. In some cases, the start-up sequence may include a step for directing a flow containing hydrogen and nitrogen to the adsorber when the target _NH3 flow rate range is reached. In some cases, the start-up sequence may include a step for directing a flow containing hydrogen and nitrogen to the adsorber when the target _NH3 decomposition rate is reached. In some cases, the start-up sequence may include a step for directing a flow containing _hydrogen and nitrogen to the adsorber, then to the fuel cell or fuel cells, and then to the combustor or combustors when (i) the reactor or reactors reach a target temperature, (ii) the target _NH3 flow rate range is reached, and (iii) the target NH3 decomposition rate is reached.

In some cases, the target temperature may be from about 400°C to about 600°C. In some cases, the target temperature may be from about 350°C to about 650°C. In some cases, the target temperature may be at least about 350°C. In some cases, the target temperature may be from about 100°C to about 600°C. In some cases, the target temperature may be from about 600°C to about 800°C.

In some cases, the startup sequence may include using one or more fuel cells to process hydrogen and generate electrical energy or power. In some cases, the startup sequence may include steps for providing electrical energy or power to a load. In some cases, the load may be one or more motors or drives for the air vehicle. In some cases, the startup sequence may include steps for providing electrical energy or power to one or more sensors, one or more components, and/or one or more auxiliary batteries.

Scalable reactor for reforming ammonia

In some aspects, the present disclosure provides a system for processing ammonia. The system may include one or more reactors for decomposing ammonia, one or more heating elements disposed in at least one of the one or more reactors, and one or more flow paths disposed around or near the one or more heating elements to improve flow fields and uniformity of heating. In some cases, the one or more heating elements may be configured to heat a fluid including one or more reformed gases as the fluid flows along one or more flow paths disposed around or near the one or more heating elements. In some cases, the one or more reformed gases may include ammonia. In some cases, the system further includes one or more catalysts configured to decompose or crack ammonia when heated by the one or more heating elements. In some cases, the one or more catalysts may be disposed external or outside the one or more heating elements.

55A and 55B show schematic views of an exterior and interior of a reactor according to one or more embodiments of the present disclosure. In some cases, the reactor may include multiple gas inlets and multiple gas outlets. In some cases, the gas inlets may be configured to receive ammonia that is decomposed by the reactor. In some cases, the gas outlets may be configured to discharge hydrogen, nitrogen, and/or unconverted ammonia. In some cases, the hydrogen and nitrogen discharged through the gas outlets may originate from ammonia that is input to the reactor for decomposition or cracking.

In some cases, the reactor may include one or more embedded heating elements. In some cases, the one or more embedded heating elements may have a shell or exterior surface in thermal communication with the fluid flowing through the reactor, which may enable improved heat transfer between (i) the fluid flowing through the reactor (e.g., through one or more flow paths surrounding the embedded heating elements) and (ii) the embedded heating elements. In some cases, the one or more heating elements may be configured to provide multiple heating zones within the reactor. In some cases, the multiple heating zones may have different temperatures, either predetermined or adjustable. In some cases, the embedded heating elements may include a combustion heater, an electric heater, or a hybrid heating element that includes both a combustion heater and an electric heater. In some cases, the embedded heating elements may make the reactor system more compact by minimizing the volume requirements of the heating elements. In some cases, the hybrid heating elements may enable faster start-up and response. In some cases, the hybrid heating elements may result in a reactor system that is more compact in volume. In some cases, the hybrid heating elements may allow the temperature to be more easily controlled. In some cases, the hybrid heating elements may allow multiple catalyst materials to be loaded. In some cases, hybrid heating elements may be used to control the temperature in multiple areas.

In some cases, the embedded heating elements may comprise different types of heaters with different start-up and response times. For example, an electric heater may have a faster response or heat-up time than a combustion heater. A combustion heater may be used for heating, but during start-up of the reactor, the electric heater may generate heat faster than the combustion heater. In some cases, the electric heater may generate heat to quickly raise the temperature of the reactor to an ideal temperature range. In some cases, if there is a sudden temperature change, the heat generation rate of the electric heater can be adjusted to quickly respond to the sudden temperature change. In some cases, the combustion heater can quickly generate heat or thermal energy and quickly respond to the sudden temperature change by supplying additional air to the combustor. In some cases, the embedded heating elements described herein may comprise both a combustion heater and an electric heater. In some cases, one or more reactors with one or more embedded electric heaters may be coupled in series or parallel with one or more reactors with one or more embedded combustion heaters. In any of the embodiments described herein, the combustion heater and the electric heater may be arranged in series or parallel in space along the longitudinal axis of the respective reactor.

FIG. 60 illustrates a schematic of a gas flow path in a reformer flow path according to one or more embodiments of the present disclosure. In some cases, ammonia may be directed to flow along the gas flow path in the flow path. In some cases, a catalyst may be disposed in the flow path and/or along the gas flow path of the ammonia such that the ammonia contacts the catalyst as it flows along the gas flow path in the flow path.

56, 58A, and 58B show schematic top and internal cross-sectional views of a reformer according to one or more embodiments of the present disclosure. In some cases, the catalyst may have an ammonia decomposition efficiency that is temperature dependent. In some cases, precise control of temperature (both spatially and temporally) may enhance reactor performance by providing an ideal temperature range for heating the catalyst and one or more gases flowing through the reformer as uniformly and quickly as possible. In some cases, an embedded heating element as described herein may be used to heat one or more catalysts to one or more ideal temperature ranges. In some cases, the catalyst may be provided outside the heating element. In some cases, a catalyst located outside the heating element may be in thermal communication with the heating element to allow transfer of thermal energy between the heating element and the catalyst. In some cases, an extended heat transfer surface may be provided outside the heating element to improve thermal communication between the catalyst and the heating element. In some cases, one or more gases and/or catalysts may have a relatively low thermal conductivity. In some cases, extended heat transfer surfaces (e.g., fins and/or baffles) may be provided in the flow passage to increase heat transfer. In some cases, extended heat transfer surfaces (e.g., fins and/or baffles) may be provided within the flow passages of the outer shell to increase heat transfer.

In some cases, the reactor or reactors may include (i) a first flow path for passing reformate gas from one or more gas inlets along a portion of one or more heating elements, and (ii) a second flow path for directing reformate gas to one or more gas outlets. In some cases, the reformate gas may include ammonia. In some cases, the reformate gas may include hydrogen and/or nitrogen. In some cases, the first flow path may be directly connected to the second flow path to allow fluid flow between the first and second flow paths. Figures 56, 58A, and 58B show schematics of a first flow path (solid arrow, 5601) and a second flow path (dotted arrow, 5602) in a reactor having a variety of different cross-sectional shapes or profiles. In some cases, the first flow path may extend along the length of the heating element from a gas inlet of the reactor to a point that redirects the gas in the reactor, and then the gas flowing along the first flow path may enter the second flow path via a gas turnaround point. In some cases, the second flow path may extend back along the length of the heating element toward a gas outlet of the reactor.

In some cases, the first flow path and the second flow path may be oriented in different directions. In some cases, the first flow path and the second flow path may be oriented in opposite directions. In some cases, a portion of the first flow path and a portion of the second flow path may be oriented in opposite directions.

In some cases, the reformate gas entering the reactor may be at a lower temperature than the reformate gas exiting the reactor. In some cases, the gas entering the reactor may flow along a first flow path and the gas exiting the reactor may flow along a second flow path. As described above, the first and second flow paths may place the gas entering the reactor in thermal communication with the gas exiting the reactor. In some cases, the first or second flow path, or both flow paths, may have heat transfer enhancement features, such as metal fins or extended heat transfer surfaces within the flow paths. By allowing the transfer of thermal energy between the gas entering the reactor and the gas exiting the reactor, the gas entering the reactor may be heated or preheated by the gas exiting the reactor, which may facilitate the heating and decomposition of the gas entering the reactor. In some cases, one or more heat exchangers or heat recovery units external to the reactor or reactors may be used to exchange heat between the reactor outlet stream and the cold inlet stream before entering the reactor.

In some cases, the first flow path and the second flow path may be disposed adjacent to one another to allow for the transfer of thermal energy between (i) one or more reformate gases entering the one or more reactors via one or more gas inlets and (ii) one or more reformate gases exiting the one or more reactors via the gas outlets. In some cases, each individual heating element of the one or more heating elements may include one or more dedicated flow paths. In some cases, each of the one or more heating elements may include different respective flow paths. In some cases, the flow paths may include one or more internal heat transfer enhancements, e.g., fins or extended heat transfer surfaces. In some cases, the outer shell within the reactor (after the gases are redirected) may function as a heat exchange flow path between the incoming cool gas and the outgoing hot reformate gas. In some cases, the outer shell may include one or more internal heat transfer enhancements, e.g., fins or extended heat transfer surfaces.

In some cases, the reactor(s) may (i) comprise one or more flow paths, and (ii) comprise one or more enclosed or partially enclosed regions surrounding the heating element(s). In some embodiments, the one or more enclosed or partially enclosed regions may allow passage of the reformed gas(s) around the heating element(s) and promote heat transfer and uniformity of the flow field between the heating element(s) and the reformed gas(s).

In some cases, the heating element(s) may comprise one or more exterior surfaces in thermal communication with the fluid flowing along or through the flow path(s). In some cases, one or more catalysts are provided adjacent to and/or in thermal communication with the exterior surfaces of the heating element(s). In some cases, the catalyst(s) may be located or provided within the flow path(s). In some cases, the flow path(s) may comprise a circular cross section that allows for uniform heating of the fluid. In some cases, the volume of the reactor external to the embedded heating element(s) may be filled with the catalyst(s). In some cases, the volume of the reactor external to the embedded heating element(s) may comprise one or more flow paths.

As described elsewhere herein, in some cases, the reactor may have a circular cross-section. The circular cross-section may allow for uniform heating of the catalyst since the catalyst is disposed at a constant or similar radial distance from the embedded heating unit. The circular cross-section may also allow for more uniform temperature and/or flow distribution within the reactor. In some cases, improved spatial uniformity of temperature and/or flow distribution within the reactor allows for more uniform heating of the catalyst within the reactor, such that the catalyst is generally heated to an ideal temperature range.

In some cases, the cross-sectional size and/or shape of the flow passage around the heating element may be adjusted or optimized to enhance flow uniformity. In some cases, the flow rate through the flow passage may vary depending on a given heating power input to a specified heating element. In some cases, multiple gas outlets can improve flow uniformity. For example, FIGS. 62A-62D show a reactor with two or four gas outlets according to one or more embodiments of the present disclosure. In some cases, the four gas outlets are symmetrically positioned such that gas flow exiting the reactor is directed to each of the four sides of the reactor. In some cases, the multiple gas outlets may be symmetrically positioned. In some cases, the multiple gas outlets may have substantially equal cross-sectional areas. In some cases, the multiple gas outlets may be positioned on one end of the reactor. In some cases, the multiple gas outlets may be positioned on multiple sides of the reactor. In some cases, the flow passages may include one or more baffles to induce turbulence, mixing, increase flow residence time, and/or improve flow uniformity and heat transfer. In some cases, increasing the length of the flow path (e.g., by using baffles) increases the flow residence time, resulting in better flow uniformity and heat transfer between (i) the embedded heating elements and (ii) the gas flowing through the reactor or reformer.

Figure 63B shows a plot of thermal reforming efficiency for the reactor design of the present disclosure as a function of ammonia flow rate. Measurements were made using electrical Joule heating only. The inlet ammonia gas flow rate was about 25°C. Incorporating one or more heat exchangers between the hot outlet stream (about 400-500°C) and the cold inlet stream (about 25°C) can significantly increase the thermal reforming efficiency (e.g., to 92-95% or more). Ammonia flow rates up to about 300 standard liters per minute (LPM) were tested, with 99% conversion at this flow rate being hydrogen equivalent to about 40 kW of power output from the fuel cell. Thus, scaling of the reactor design to support 100 kW or more operation may be possible, for example, with reactors having longer lengths, or larger flow path dimensions and heating elements, or more flow paths and heating elements, or by stacking modular reactors. Reactors can be constructed with great flexibility in form factors, allowing multiple modular reactors to be used in a system.

Several designs without flow paths were also tested. In some designs without flow paths, the efficiency and conversion were outside the measured range (i.e., less than 80% ammonia conversion). In some designs without flow paths, it was found that some heating elements overheated due to insufficient heat transfer.

In some cases, the reactors disclosed herein may have a thermal reforming efficiency of at least about 90%. In some cases, the reactors disclosed herein may have a thermal reforming efficiency of at least about 50, 60, 70, 80, 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99%. In some cases, the reactors disclosed herein may have a thermal reforming efficiency of up to about 50, 60, 70, 80, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99%, or 100%.

Figure 63B shows a plot of ammonia conversion efficiency for reactor designs of the present disclosure as a function of ammonia flow rate. In some cases, the reactor may have an ammonia conversion efficiency of at least about 95%. In some cases, the reactor may have an ammonia conversion efficiency of at least about 50, 60, 70, 80, 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99%. In some cases, the reactor may have an ammonia conversion efficiency of up to about 50, 60, 70, 80, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99%, or 100%.

The reactors of the present disclosure may be suitably sized to generate various levels of power. In some cases, the reactor may be configured to output at least about 25 kilowatts of power. In some cases, the reactor may be configured to output at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 200, 300, 400, or 500 kilowatts of power. In some cases, the reactor may be configured to output up to about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 200, 300, 400, or 500 kilowatts of power. In some cases, the reactor may be configured to output up to about 0.1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50 megawatts of power.

In some cases, the system may further include a plurality of different catalysts for decomposing ammonia. In some cases, the plurality of different catalysts may be in thermal communication with at least one of the one or more heating elements. FIGS. 59A and 59B show schematic exterior and interior views of a reactor having two catalysts according to one or more embodiments of the present disclosure. In some cases, the two catalysts can be provided in two different regions or heating zones (e.g., a low temperature region and a high temperature region). In some cases, a first catalyst that is efficient at a lower temperature may be provided in the first region, and a second catalyst that is efficient at a higher temperature may be provided in the second region. In some cases, the first region may be closer to the gas inlet and/or gas outlet of the reactor than the second region. In some cases, the one or more reactors having one or more heating elements may be in fluid communication with the one or more reactors having one or more heating elements. For example, multiple modular reactors in fluid communication in series or parallel can increase the overall hydrogen production output. In some cases, the one or more reactors having one or more electric heating elements may be in fluid communication with the one or more reactors having one or more combustion heating elements. In some cases, the reactor(s) having one or more electric heating elements may operate at a lower temperature than the reactor(s) having one or more combustion heating elements. In this case, the outlet stream of the electrically heated reactor may enter the combustion heated reactor as an inlet stream to further improve ammonia conversion and/or thermal reforming efficiency. In some cases, the reactor(s) having one or more combustion heating elements may operate at a lower temperature than the reactor(s) having one or more electric heating elements. In some cases, the outlet stream of the combustion heated reactor may enter the electrically heated reactor as an inlet stream to further improve ammonia conversion and/or thermal reforming efficiency.

In some cases, the plurality of different catalysts may include a first catalyst having a first set of ammonia reforming properties and a second catalyst having a second set of ammonia reforming properties. In some cases, the ammonia reforming properties may include, for example, thermal reforming efficiency as a function of temperature, or thermal reforming efficiency as a function of ammonia conversion. In some cases, the first catalyst and the second catalyst may be in thermal communication with different heating elements, different locations or regions of the same heating element, or different heating zones generated by one or more heating elements. In some cases, the one or more heating elements may be configured to provide multiple heating zones within the reactor. In some cases, the multiple heating zones may have different temperatures, either predetermined or adjustable.

In some cases, the first catalyst and the second catalyst may have different ideal temperature ranges for decomposing ammonia. In some cases, the first catalyst and the second catalyst are provided in different regions or heating zones within the reactor, and the first catalyst and the second catalyst are heated to their corresponding ideal temperature ranges. In some cases, the first catalyst may be heated to a lower temperature range than the second catalyst. In some cases, the first catalyst may be heated to a higher temperature range than the second catalyst. In some cases, the first catalyst and the second catalyst may be in thermal communication with different heating elements, different locations or regions of the same heating element, or different heating zones generated by one or more heating elements. In some cases, the first catalyst and the second catalyst may be separated into different reactors that are in fluid communication with each other.

In some cases, the heating element or elements may be configured to (i) control the temperature of one or more heating elements or different regions of one or more reactors, or (ii) adjust the position of one or more heating zones within one or more reactors to optimize the efficiency of thermal reforming and/or conversion of ammonia.

In some cases, the system may further include a controller configured to control the flow of ammonia into one or more flow paths by adjusting one or more flow control units. In some cases, the controller may be configured to control the flow of ammonia based on a heating power input to each of the one or more heating elements. In some cases, the system may further include a controller configured to control the operation or temperature of the one or more heating elements. In some cases, the controller can set or maintain a uniform temperature distribution within the reactor. In some cases, the uniform temperature distribution can correspond to a spatial or temporal uniformity of temperature or heating. In some cases, the controller can maintain a uniform flow distribution among one or more flow paths within the reactor.

In some cases, the system may further include one or more heat exchangers between the hot outlet and cold inlet streams of the reactor. In some cases, the controller may be configured to execute a start-up protocol to heat the reactor to a predetermined temperature range within a predetermined time. In some cases, the controller may be operatively coupled to one or more sensors to sense (i) the temperature of the one or more heating elements, or (ii) the flow rate of the ammonia or hydrogen/nitrogen mixture into or out of the flow path, or (iii) one or more pressures at various locations of the one or more reactors. In some cases, the controller may be configured to execute one or more control loops, such as a proportional-integral-derivative (PID), proportional-integral (PI), or proportional (P) control loop, to regulate the temperature. In some cases, controlling the operation of the heating element may involve controlling the heating power input to the heating element. In some cases, the one or more flow control units may include one or more valves and/or one or more pressure sensors.

The reactors disclosed herein may comprise a variety of shapes or sizes. For example, Figures 55A and 55B show schematic exterior and interior views of a reactor having a circular cross-section with multiple gas inlets and multiple gas outlets. In another example, Figures 57A and 57B show schematic exterior and interior views of a reactor having a square cross-section with multiple gas inlets and multiple gas outlets. Figure 61 shows another non-limiting example of various reactor configurations. In some cases, the reactor may comprise a variety of other cross-sectional shapes or profiles, including, but not limited to, triangular, rectangular, pentagonal, hexagonal, heptagonal, or octagonal shapes or profiles. In some cases, one or more reactors may comprise a cross-sectional shape including a circle, an ellipse, an oval, or any polygon with three or more sides. In some cases, one or more reactors may comprise a cross-sectional shape similar to the cross-sectional shape of the flow path. In some cases, one or more reactors may comprise a cross-sectional shape different from the cross-sectional shape of the flow path.

In some cases, the cross-sectional shape of the reactor may allow for stacking of multiple reactors. In some cases, multiple reactors may be stacked horizontally (i.e., on their sides) or vertically (i.e., upright). In some cases, multiple reactors may be stacked in a rectangular or square grid pattern. In some cases, multiple reactors may be stacked in a hexagonal grid pattern (i.e., honeycomb). In some cases, multiple reactors may be stacked and linearly connected.

The reactors disclosed herein may include any number of gas inlets and gas outlets. In some cases, the reactor may include one or more gas inlets or gas outlets. In some cases, the reactor may include two or more gas inlets or gas outlets. In some cases, the reactor may include a single gas inlet and/or a single gas outlet. In some cases, the reactor may include a single gas inlet and/or a single gas outlet, while the flow is internally distributed into one or more flow paths. In some cases, the reactor may include at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100 gas inlets or gas outlets. In some cases, the reactor may include up to about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100 gas inlets or gas outlets.

In some cases, the gas inlet(s) can be oriented parallel to the length of the reactor. In some cases, the gas inlet(s) can be oriented perpendicular to the length of the reactor. In some cases, the gas outlet(s) can be oriented parallel to the length of the reactor. In some cases, the gas outlet(s) can be oriented perpendicular to the length of the reactor. The gas inlets and/or gas outlets can be oriented in any direction relative to the reactor.

The reactor may have a variety of length-to-width ratios. FIGS. 62A-62D show examples of reactor designs having different length-to-width ratios according to one or more embodiments of the present disclosure. FIG. 62A shows a first design having a square shape. FIG. 62B shows a second design having a square shape, but with a length 50% longer than the first design. FIG. 62C shows a third design having a square shape, but with flow channels and heater diameters 50% larger than the first design. FIG. 62D shows a fourth design having a cylindrical shape with the same flow channels and heater diameters as the second design. In some cases, the length of the reactor may be at least about 5 times longer than the width or diameter of the reactor. In some cases, the length of the reactor may be at least about 2, 3, 4, 5, 6, 7, 8, 9, or 10 times longer than the width or diameter of the reactor. In some cases, the length of the reactor may be up to about 2, 3, 4, 5, 6, 7, 8, 9, or 10 times longer than the width or diameter of the reactor. In some cases, the length of the reactor may be up to about 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 times longer than the width or diameter of the reactor.

In any of the embodiments described herein, the system or power pack unit may include a pressure swing adsorption (PSA) or membrane separation unit. The PSA or membrane separation unit may be configured to remove nitrogen from the outlet stream of the one or more reactors. The PSA or membrane separation unit may be installed or disposed downstream of one or more adsorber in fluid communication with the one or more reactors. The PSA or membrane separation unit may be installed or disposed upstream of the one or more fuel cells. In some cases, the PSA or membrane separation unit may be further configured to remove trace ammonia from the outlet stream from the one or more adsorber or one or more reactors. In some cases, the PSA or membrane separation unit may be configured to process the outlet stream from the one or more adsorber or one or more reactors to create an exhaust stream comprising nitrogen and hydrogen. In some cases, the exhaust stream may be fed to a fired heater of the one or more reactors.

In some embodiments, the system or power pack unit may include one or more combustors. In some cases, the one or more combustors may consume about 15 to 50 percent of the total hydrogen produced from the ammonia reforming as a combustion fuel. In some cases, the one or more combustors may consume about 30 to 40 percent of the total hydrogen produced from the ammonia reforming as a combustion fuel. In some cases, the one or more combustors may consume about 25 to 45 percent of the total hydrogen produced from the ammonia reforming as a combustion fuel. In some cases, the one or more combustors may consume less than about 30 percent of the total hydrogen produced from the ammonia reforming as a combustion fuel. In some cases, the one or more combustors may consume less than about 25 percent of the total hydrogen produced from the ammonia reforming as a combustion fuel. In some cases, the one or more combustors may consume less than about 80, 70, 60, 50, 40, 30, 20, or 10 percent of the total hydrogen produced from the ammonia reforming as a combustion fuel. In some cases, the combustor or combustors may consume more than about 80, 70, 60, 50, 40, 30, 20, or 0 percent of the total hydrogen produced from reforming ammonia as a combustion fuel.

In one or more embodiments described herein, the one or more electric heaters at least partially embedded in the one or more reactors may heat only during start-up operation. In some cases, the one or more electric heaters are intermittently turned on and off during operation, either by automatically turning the electric heaters on and off (e.g., based on temperatures measured at the reactors and/or heaters) or by manually turning the electric heaters on and off (e.g., based on user input to an input device, e.g., a button, switch, knob, mouse, keyboard, etc.). In some cases, the one or more electric heaters provide about 30%-50% of the total heating power required during operation. In some cases, the one or more electric heaters provide about 15%-40% of the total heating power required during operation. In some cases, the one or more electric heaters provide less than about 15% of the total heating power required during operation. In some cases, the one or more electric heaters provide about 50%-70% of the total heating power required during operation. In some cases, the one or more electric heaters intermittently provide at least 70% of the total heating power required. In some cases, the electric heater or heaters intermittently provide about 100% of the total heating power required. In some cases, the total heating power required is based on the sum of Joule heating and combustion energy input to sustain autothermal reforming.

In any of the embodiments described herein, the system or power pack unit may output a lower heating value of ammonia to a useful electrical conversion efficiency of about 20-60%. In some cases, the system or power pack unit may output a lower heating value of ammonia to a useful electrical conversion efficiency of about 30-50%. In some cases, the system or power pack unit may output a lower heating value of ammonia to a useful electrical conversion efficiency of about 35-45%. In some cases, the system or power pack unit may output a lower heating value of ammonia to a useful electrical conversion efficiency of greater than about 35%.

In any of the embodiments described herein, the one or more fired heaters at least partially embedded in the one or more reactors may have a combustion fuel and airflow pressure drop across the one or more fired heaters of less than 5 bar. In some cases, the one or more fired heaters may have a combustion fuel and airflow pressure drop across the one or more fired heaters of less than 2 bar. In some cases, the one or more fired heaters may have a combustion fuel and airflow pressure drop across the one or more fired heaters of less than 1 bar. In some cases, the one or more fired heaters may have a combustion fuel and airflow pressure drop across the one or more fired heaters of less than 0.5 bar.

In any of the embodiments described herein, the system or power pack unit can be utilized in stationary and/or mobile applications. Stationary applications may involve the generation of electricity or hydrogen for a non-mobile application or platform (e.g., to supply power and/or hydrogen to a network or grid). Mobile applications involve the generation of electricity and/or hydrogen for a mobile application or platform (e.g., a vehicle or other mobile platform).

While the present specification has shown and described preferred embodiments of the present invention, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. The present invention is not intended to be limited by the specific examples provided herein. Although the present invention has been described with reference to the foregoing specification, the description and illustration of the embodiments herein are not intended to be construed in a limiting sense. Numerous variations, changes, and substitutions will occur to those skilled in the art without departing from the present invention. Furthermore, it should be understood that all aspects of the present invention are not limited to the specific descriptions, configurations, or relative proportions set forth herein, which depend upon a variety of conditions and variables. It should be understood that various alternatives to the embodiments of the present invention described herein can be used in practicing the present invention. It is therefore intended that the present invention cover any such alternatives, modifications, variations, or equivalents. The following claims define the scope of the present invention, and methods and structures within the scope of these claims and their equivalents are intended to be covered thereby.

Claims (95)

1. A system comprising:
one or more reactors in fluid communication with one or more ammonia sources, said one or more reactors comprising one or more catalysts;
a plurality of heating elements in thermal communication with the one or more catalysts;
the one or more reactors are configured to make or produce hydrogen from ammonia provided by or received from the one or more ammonia sources using the one or more catalysts and the multiple heating elements;
The system, wherein the plurality of heating elements comprises at least one electric heater and at least one fired heater. The system of claim 1, wherein the one or more reactors comprise a first reactor and a second reactor in fluid communication with the first reactor. The system of claim 2, wherein the first reactor comprises (i) a first catalyst and (ii) a start-up heating unit configured to heat the first catalyst, the first catalyst configured to produce or extract the hydrogen from the ammonia. The system of claim 3, wherein the power-on heating unit comprises the at least one electric heater. The system of claim 4, wherein the at least one electric heater comprises one or more electrodes for passing an electric current through the first catalyst to heat the first catalyst. The system of claim 2, wherein the second reactor comprises (i) a second catalyst and (ii) one or more main heating units configured to heat the second catalyst, the second catalyst configured to produce or extract the hydrogen from the ammonia. The system of claim 6, wherein the one or more main heating units comprise the at least one fired heater. The system of claim 7, wherein the at least one fired heater is configured to heat at least a portion of the second catalyst by combusting the hydrogen produced by the first reactor. The system of claim 1, further comprising the one or more ammonia sources. The system of claim 9, wherein the one or more ammonia sources comprise one or more liquid fuel storage tanks, and the ammonia is stored as liquid ammonia in the one or more liquid fuel storage tanks. The system of claim 10, wherein the liquid ammonia is stored at a temperature in the range of about 15 to about 30°C and at a pressure in the range of 7 to 12 bar absolute. The system of claim 10, wherein the liquid ammonia is stored at a gauge pressure ranging from about atmospheric pressure to about 20 bar. The system of claim 10, wherein the liquid ammonia is stored at a temperature in the range of about -40 to about 20°C and at an absolute pressure in the range of about 0.5 bar to about 9 bar. The system of claim 1, further comprising one or more fuel cells in fluid communication with the one or more reactors. The system of claim 14, further comprising one or more adsorbents in fluid communication with the one or more reactors and the one or more fuel cells, the one or more adsorbents configured to filter or remove unconverted ammonia from an outlet stream from the one or more reactors. The system of claim 15, wherein the one or more adsorbents are configured to provide a filtered reactor outlet stream to the one or more fuel cells. 17. The system of claim 16, wherein the one or more fuel cells are configured to: (i) receive the filtered reactor outlet stream from the one or more adsorber; (ii) process the filtered reactor outlet stream to generate electricity; and (iii) discharge a fuel cell outlet stream comprising unconverted hydrogen. The system of claim 17, wherein one or more of the plurality of heating elements are in fluid and/or thermal communication with the fuel cell outlet stream. The system of claim 18, wherein the one or more heating elements are configured to combust the unconverted hydrogen to heat the one or more catalysts. The system of claim 1, wherein the one or more reactors include one or more flow paths for the ammonia, the one or more flow paths (i) surrounding at least one heating element of the plurality of heating elements, and (ii) allowing flow of the ammonia around the at least one heating element to facilitate heat transfer between the heating element and the ammonia. The system of claim 1, wherein the one or more reactors include one or more flow paths adjacent to the plurality of heating elements, the flow paths permitting flow of the ammonia adjacent to or along the one or more heating elements to facilitate heat transfer between the one or more heating elements and the ammonia. The system of claim 20 or 21, wherein each of the one or more flow paths is concentric or coaxial with a respective one of the one or more heating elements relative to a longitudinal axis. The system of claim 20 or 21, wherein the plurality of heating elements are in fluid and/or thermal communication with the ammonia flowing along or through the one or more flow paths. The system of claim 20 or 21, wherein the one or more flow channels are provided around or near the heating element to improve flow field and heating uniformity. The system of claim 20 or 21, wherein the heating element is configured to heat the ammonia as the ammonia flows along or through the one or more flow paths disposed around or near the heating element. The system of claim 1, wherein the at least one fired heater is configured to combust an outlet stream from the one or more reactors to generate thermal energy for heating the one or more reactors. The system of claim 1, wherein the at least one fired heater is configured to combust an outlet stream from one or more adsorbents in fluid communication with the one or more reactors to generate thermal energy for heating the one or more reactors. The system of claim 1, wherein the at least one fired heater is configured to combust an outlet stream from one or more fuel cells in fluid communication with the one or more reactors to generate thermal energy for heating the one or more reactors. The system of claim 1, wherein the at least one fired heater comprises a swirl combustor, a diffusion flame combustor, a micro-mixer combustor, or any combination thereof. The system of claim 1, wherein the exhaust of the at least one fired heater can be used to heat or preheat the ammonia. The system of claim 1, wherein the at least one fired heater is configured to combust a mixture of air and a combustion fuel comprising hydrogen. 32. The system of claim 31, wherein the at least one fired heater comprises one or more zones for mixing or premixing the air and the combustion fuel upstream of a combustion region of the at least one fired heater. The system of claim 32, wherein each of the one or more zones is configured to combust or pre-combust at least a portion of the mixture of air and the combustion fuel to distribute heat evenly throughout the fired heater and reduce localized hot spot temperatures. The system of claim 1, wherein the plurality of heating elements comprises a hybrid heating unit comprising the at least one electric heater and the at least one combustion heater. The system of claim 2, wherein the first reactor is equipped with the at least one electric heater and the second reactor is equipped with the at least one fired heater. The system of claim 2, wherein the first reactor and the second reactor are in fluid communication in series such that a first outlet stream of the first reactor enters the second reactor. The system of claim 2, wherein the first reactor and the second reactor are in parallel fluid communication such that a first outlet stream of the first reactor and a second outlet stream of the second reactor intermix to produce a intermixed outlet stream. The system of claim 1, wherein the one or more catalysts are disposed adjacent to and/or in thermal communication with one or more exterior surfaces of the heating element. The system of claim 1, wherein the one or more reactors have a cross-sectional shape selected from the group consisting of a circle, an ellipse, an oval, and any polygon having three or more sides. The system of claim 1, wherein the one or more reactors include one or more flow channels having a cross-sectional shape selected from the group consisting of a circle, an ellipse, an oval, and any polygon having three or more sides. The system of claim 1, wherein each of the one or more reactors has a cross-sectional shape similar to a cross-sectional shape of a flow passage of each of the one or more reactors. The system of claim 1, wherein each of the one or more reactors has a cross-sectional shape that is different from the cross-sectional shape of the flow passage of each respective reactor of the one or more reactors. The system of claim 1, wherein the one or more reactors comprise: (i) a first flow path for a reformate gas containing the ammonia; and (ii) a second flow path for a reformate gas produced from processing the reformate gas. The system of claim 43, wherein the first flow path enables flow of the reformulated gas along at least a portion of the plurality of heating elements. The system of claim 43, wherein the second flow path allows the reformate gas to flow to one or more outlets of the reactor. The system of claim 43, wherein the first flow path and the second flow path are oriented in different directions. The system of claim 43, wherein the first flow path and the second flow path are in fluid communication with each other to enable heat transfer between the reformed gas and the reformate gas. The system of claim 1, further comprising one or more heat exchangers. The system of claim 48, wherein the one or more heat exchangers are configured to exchange heat between an outlet stream of the one or more reactors and the flow of ammonia from the one or more ammonia sources. The system of claim 48, wherein the one or more heat exchangers are configured to facilitate the transfer of thermal energy between (i) the flow of ammonia from the one or more ammonia sources and (ii) one or more fuel cells in fluid communication with the one or more reactors to vaporize the ammonia. The system of claim 1, further comprising one or more control units for regulating the temperature of the outlet stream of the one or more reactors and/or the plurality of heating elements. 52. The system of claim 51, wherein the one or more control units comprise a controller and one or more sensors operably coupled to the controller. 53. The system of claim 52, wherein the controller is configured to monitor and control (i) the temperature of the one or more reactors, (ii) the ammonia and/or hydrogen flow pressure, and/or (iii) the electrical output of one or more fuel cells in fluid communication with the one or more reactors based at least in part on one or more measurements obtained using the one or more sensors. 53. The system of claim 52, wherein the controller is configured to decrease or increase an air flow rate, decrease or increase a combustion fuel flow rate, or decrease or increase both the air flow rate and the combustion fuel flow rate to the at least one fired heater based on the temperature of the one or more reactors. The system of claim 54, wherein the controller is configured to increase the air flow rate using a fan, blower, or compressor. 55. The system of claim 54, wherein the controller is configured to increase the combustion fuel flow rate by increasing ammonia flow rate or decreasing fuel cell hydrogen consumption. 53. The system of claim 52, wherein the controller is configured to decrease or increase the power output of the one or more fuel cells based on the temperature of the one or more reactors. 53. The system of claim 52, wherein the controller is configured to increase the flow rate of the ammonia to the one or more reactors based on the temperature of the one or more reactors or the power output of the one or more fuel cells. The system of claim 58, wherein the controller is configured to increase the flow rate of the ammonia using a valve and/or a pump. The system of claim 1, wherein the system is configured to reform the ammonia at a rate of at least about 50 L/min of ammonia gas at STP. 53. The system of claim 52, wherein the controller is configured to increase or decrease the power supplied to the at least one electric heater based on the temperature of the one or more reactors. The system of claim 1, wherein the system has an energy density of at least about 600 Wh/kg, or at least about 400 Wh/L. The system of claim 1, wherein the system has an operating pressure of less than about 30 bar. The system of claim 1 further comprising a pressure swing adsorption (PSA) unit for removing nitrogen from the outlet stream of the one or more reactors. The system of claim 64, wherein the PSA is installed or disposed downstream of one or more adsorbents in fluid communication with the one or more reactors. The system of claim 64, wherein the PSA unit produces an exhaust stream comprising nitrogen and hydrogen, the exhaust stream being fed to the at least one fired heater. The system of claim 16, wherein the filtered reactor outlet stream contains less than 100 ppm ammonia. The system of claim 16, wherein the one or more adsorbents are configured to be regenerated by exchanging heat with one or more electric heaters embedded in the one or more adsorbents, exhaust from the at least one fired heater, and/or an outlet stream from the one or more reactors. The system of claim 68, wherein the one or more adsorbents are replaceable with one or more new or regenerated adsorbents. The system of claim 1, wherein the one or more catalysts include a support and at least one metal selected from ruthenium, nickel, rhodium, iridium, cobalt, iron, platinum, chromium, palladium, molybdenum, tantalum, or copper. The system of claim 70, wherein the one or more catalysts are promoted with at least one metal selected from Li, Na, K, Rb, Cs, Mg, Ca, Ba, Sr, La, Ce, Pr, Sm, or Gd. 71. The system of claim ₇₀ , wherein the support comprises at _least one material selected from _Al2O3 , _MgO , _CeO2 , _{ZrO2, La2O3 , SiO2 , Y2O3} , _TiO2 , SiC, hexagonal BN (boron nitride), BN nanotubes, silicon carbide, one or more zeolites, _LaAlO3 , _CeAlO3 , _{MgAl2O4 , CaAl2O4} , or one or more carbon nanotubes. The system of claim 2, wherein the first reactor is configured to initiate the ammonia reforming process. The system of claim 73, wherein the reforming process is initiated using an electric current passing through the at least one electric heater or the one or more catalysts. The system of claim 74, wherein the at least one electric heater or the current is stopped after the reforming process is initiated. The system of claim 14, wherein the one or more fuel cells consume less than 90% of the hydrogen from the one or more reactors and discharge one or more outlet streams containing the remaining unconverted hydrogen. The system of claim 1, wherein the operating temperature of the one or more reactors is less than 900°C. The system of claim 1, further comprising one or more pumps for supplying the ammonia and increasing the flow pressure of the ammonia. The system of claim 1, wherein the system does not emit carbon. The system of claim 1, wherein the fuel reforming or conversion rate of the one or more reactors is greater than about 90%. The system of claim 1, wherein the fuel heating value to useful electrical energy output efficiency of the system is at least about 25% and at most about 50%. The system of claim 1, further comprising one or more batteries, one or more DC/DC converters, and one or more motors for driving the mobile vehicle. The system of claim 82, wherein the one or more batteries provide power to power the system. The system of claim 83, wherein the one or more batteries are configured to provide electrical power to power the system by providing the electrical power to the at least one electric heater. The system of claim 82, further comprising one or more fuel cells for generating electrical power, the electrical power generated using the one or more fuel cells charging the one or more batteries after initiating or completing a start-up process. The system of claim 85, wherein the one or more fuel cells provide a substantially stable power or load to the mobile vehicle, and the one or more batteries enable dynamic load following capabilities. The system of claim 86, wherein the mobile vehicle includes an aerial vehicle, an unmanned aerial vehicle, a marine or underwater vehicle, or a terrestrial vehicle. The system of claim 1, further comprising one or more fuel cells for generating electrical power, the electrical power generated using the one or more fuel cells being supplied to a fixed or non-mobile platform or network. The system of claim 88, wherein the fixed or non-mobile platform or network comprises a power grid. The system of claim 1, wherein the plurality of heating elements are at least partially embedded within the one or more reactors. 1. A system comprising:
one or more reactors in fluid communication with one or more ammonia sources;
at least one heating element disposed at least partially within the one or more reactors;
The one or more reactors include a plurality of flow paths surrounding the at least one heating element to improve flow field and heating uniformity of ammonia received from or supplied by the one or more ammonia sources, the plurality of flow paths providing a flow path for the ammonia adjacent to the at least one heating element to facilitate transfer of thermal energy between the at least one heating element and the ammonia. 1. A system comprising:
one or more reactors configured to at least partially decompose ammonia provided to the one or more reactors to obtain hydrogen, nitrogen, and/or ammonia;
one or more fuel cells in fluid communication with the one or more reactors, the one or more fuel cells configured to receive and process the hydrogen to produce electrical energy;
The system, wherein the one or more reactors and the one or more fuel cells are configured to be mounted on or to an air vehicle, and the one or more fuel cells are in electrical communication with and power one or more motors or drive devices of the air vehicle. 1. A method comprising:
(a) processing ammonia to make or produce hydrogen using one or more reactors, the one or more reactors comprising: (i) one or more catalysts; and (ii) a plurality of heating elements in thermal communication with the one or more catalysts, the plurality of heating elements comprising at least one electric heater and at least one fired heater;
(b) supplying the hydrogen to one or more fuel cells to produce electrical energy. 1. A system comprising:
1. A system comprising: an ammonia treatment apparatus comprising a plurality of reactors, the plurality of reactors comprising one or more electric reactors configured to: (i) process ammonia to produce hydrogen; and (ii) supply at least a portion of the hydrogen to the one or more combustion reactors and/or one or more fuel cells in fluid communication with the one or more electric reactors and/or one or more combustion reactors. 1. A method comprising:
(a) heating an electric reactor to a first target temperature;
(b) reforming ammonia using the electric reactor to produce a fuel comprising at least hydrogen;
(c) heating a combustion reactor to a second target temperature by combusting the fuel produced in (b); and
(d) supplying additional ammonia to the combustion reactor, the combustion reactor configured to (i) crack the additional ammonia to produce additional hydrogen, and (ii) supply the additional hydrogen to one or more fuel cells.