Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
  • H01M8/04082—Arrangements for control of reactant parameters, e.g. pressure or concentration
  • H01M8/04201—Reactant storage and supply, e.g. means for feeding, pipes
  • H01M8/04208—Cartridges, cryogenic media or cryogenic reservoirs
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/30—Hydrogen technology
  • Y02E60/36—Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/30—Hydrogen technology
  • Y02E60/50—Fuel cells

Definitions

• the invention relates to generating hydrogen gas using fuel solutions of borohydride compounds. More particularly, the invention relates to a fuel cartridge and hydrogen generation apparatus having a volume-exchange configuration for the storage of fuel solution, hydrogen gas, and a hydrogen separation region.
• Hydrogen is the fuel of choice for fuel cells; however, its widespread use is complicated by the difficulties in storing the gas.
• Many hydrogen carriers, including hydrocarbons, metal hydrides, and chemical hydrides are being considered as hydrogen storage and supply systems. In each case, specific systems need to be developed in order to release the hydrogen from its carrier, either by reformation as in the case of hydrocarbons, desorption from metal hydrides, or catalyzed hydrolysis of chemical hydrides.
• One of the more promising systems for hydrogen storage and generation utilizes borohydride compounds as the hydrogen storage media.
• Sodium borohydride (NaBHi) is of particular interest because it can be dissolved in alkaline water solutions with virtually no reaction; in this case, the stabilized alkaline solution of sodium borohydride is referred to as fuel. Furthermore, the aqueous borohydride fuel solutions are non- volatile and will not burn. These traits impart handling and transport ease both in the bulk sense and within the hydrogen generator itself.
• Hydrogen generation systems have been developed for the production of hydrogen gas from aqueous sodium borohydride fuel solutions. Such generators typically require chambers to store fuel, borate product, and a catalyst or other reagent to promote hydrolysis of the borohydride. Hydrogen generation systems can also incorporate additional components such as hydrogen ballast tanks, heat exchangers, condensers, and gas-liquid separators.
• a fuel cell power system for small applications needs to be compact and lightweight, have a high gravimetric hydrogen storage density, and preferably be operable in any orientation. Additionally, it should be easy to match the control of the system's hydrogen flow rate and pressure to the operating demands of the fuel cell.
• the invention relates to apparatus and methods for generating hydrogen gas using a catalyst or reagent and a boron hydride compound.
• One embodiment of the present invention provides a hydrogen gas generator with a housing having a fuel storage chamber, a hydrogen storage chamber, and a hydrogen separation chamber wherein both of the hydrogen separation and fuel storage chambers include at least one gas permeable membrane to transport hydrogen out of the respective chambers.
• Another preferred embodiment of the present invention utilizes a volume exchanging configuration having a fuel storage chamber enclosed within both a hydrogen storage chamber and a hydrogen separation chamber, wherein both the hydrogen separation and fuel storage chambers have at least one gas permeable membrane located therein.
• a hydrogen generator capable of forming hydrogen gas, comprising a fuel storage chamber; a hydrogen storage region; and a pump for removing fuel from the fuel storage chamber; wherein the fuel storage chamber comprises a fuel outlet for removing the fuel and at least one gas permeable membrane to allow hydrogen gas generated by the fuel to pass through the gas permeable membrane to the hydrogen storage region; and a hydrogen outlet to allow hydrogen gas to pass from the hydrogen storage region to outside of the system.
• the invention provides a hydrogen gas generator, comprising a hydrogen separation chamber; a hydrogen storage chamber; a fuel storage chamber at least partially enclosed within the hydrogen storage chamber; a first conduit for conveying a fuel solution from the fuel storage chamber to a reaction chamber to promote reaction of the fuel solution to produce hydrogen and product material, and a second conduit for conveying the hydrogen and product material from the reaction chamber to the hydrogen separation chamber; a hydrogen gas outlet for discharging hydrogen from the hydrogen separation chamber; and at least one gas permeable membrane in contact with each of the fuel storage chamber and the hydrogen separation chamber to allow hydrogen gas to pass through the gas permeable membrane while substantially preventing solid and liquid materials from passing through the gas permeable membrane.
• the present invention further provides methods for hydrogen gas generation, comprising providing a fuel storage chamber, a fuel solution, a hydrogen storage chamber, and a hydrogen separation chamber.
• the fuel chamber is located at least partially within the hydrogen storage chamber
• the hydrogen storage chamber is located at least partially within the hydrogen separation chamber.
• At least a first gas permeable membrane is provided in contact with the fuel solution storage chamber, and at least a second gas permeable membrane in contact with the hydrogen separation chamber, to allow hydrogen to pass through the first and second gas permeable membranes.
• the fuel solution is conveyed from the fuel solution storage chamber to a reaction chamber for generating hydrogen gas and a product material.
• the product material and hydrogen gas are conveyed from the reaction chamber to the hydrogen separation chamber.
• the hydrogen storage chamber is maintained at a lower pressure than the fuel solution chamber.
• FIGS. IA and IB are schematic illustrations of a fuel container for a hydrogen gas generation system in accordance with the invention.
• Figure 2 is a schematic illustration of an alternative configuration of a fuel container for a hydrogen gas generation system in accordance with the invention
• Figures 3A and 3B are schematic illustrations of an arrangement for a fuel cartridge for a hydrogen gas generation system in accordance with the invention
• Figures 4A and 4B are schematic illustrations of an alternative arrangement for a fuel cartridge for a hydrogen gas generation system.
• Figure 5 is a schematic illustration of an arrangement for a preferred hydrogen gas generation system in accordance with the present invention.
• a hydrogen gas generation system that comprises a housing that includes a volume exchanging configuration having a fuel storage chamber containing a first flexible bag and a hydrogen separation chamber containing a second flexible bag where either or both of these flexible bags may have a gas permeable membrane located therein.
• Such systems meter the flow of the hydrogen generation fuel primarily through a passive pressure system, wherein applied mechanical pressure from a spring or the like or applied gas pressure forces the fuel through a valve into a reaction chamber. Control of hydrogen generation is imparted by pressure regulation.
• the liquid hydrogen generation fuel is stable (i.e., little to no hydrogen generation is observed) at temperatures below about 40°C, but hydrogen can evolve as the temperature increases.
• hydrogen gas that is produced spontaneously from the fuel solution in the fuel storage chamber can be driven though the membranes in the fuel storage chamber and into the main body of the housing by the same pressure differential that is used to push the fuel through the control valve to the reaction chamber.
• Pumps are often smaller volumetrically and gravimetrically than a spring mechanism, and pumps offer the potential to reverse fuel flow to actively withdraw fuel from the reaction chamber.
• no pressure differential would be available to remove hydrogen gas from the fuel solution and the fuel storage chamber.
• the presence of gas bubbles in the fuel solution is undesirable; for instance, bubbles can cause the pump to cavitate.
• any hydrogen trapped in the fuel solution is potentially unavailable for delivery to the hydrogen device or for conversion to electrical power by a fuel cell.
• a system and method is provided to create a pressure differential in a pumped system in order to remove hydrogen from the hydrogen generation fuel solution and the fuel storage chamber.
• the hydrogen generation fuel useful in these and the following aspects of the present invention is preferably a boron hydride compound that is a liquid or that can be formulated as a flowable fuel.
• Many of the boron hydride compounds are water soluble and aqueous flowable fuel solutions may be prepared as aqueous mixtures which may contain a stabilizer component, such as a metal hydroxide having the general formula M(OH) n , wherein M is a cation selected from the group consisting of alkali metal cations such as sodium, potassium or lithium, alkaline earth metal cations such as calcium, aluminum cation, and ammonium cation, and n is equal to the charge of the cation.
• Nonaqueous flowable fuels also can be prepared as dispersions or emulsions in nonaqueous solvents, for example, as dispersions in mineral oil, or as a solution in, for example, toluene, glymes, or acetonitrile.
• Boron hydrides as used herein include boranes, polyhedral boranes, and anions of borohydrides or polyhedral boranes, such as those provided in co-pending U.S. Patent Application Serial No. 10/741,199, entitled “Fuel Blends for Hydrogen Generators,” the content of which is hereby incorporated herein by reference in its entirety.
• M is preferably sodium, potassium, lithium, or calcium.
• the boron hydride fuels may be prepared as aqueous mixtures and may contain a stabilizer component, such as a metal hydroxide having the general formula M(OH) n , wherein M is a cation selected from the group consisting of alkali metal cations such as sodium, potassium or lithium, alkaline earth metal cations such as calcium, aluminum cation, and ammonium cation, and n is equal to the charge of the cation.
• the hydrogen generation fuel is preferably a stabilized metal borohydride solution such as described in U.S. Patent No. 6,534,033, entitled “A System for Hydrogen Generation,” the content of which is hereby incorporated herein by reference in its entirety, from which hydrogen is produced as shown in Equation 1, where MBH 4 and MB(OH) 4 , respectively, represent an alkali metal borohydride and an alkali metal me tabor ate:
• a fuel container 100 for a hydrogen gas generation system includes an outer housing 102 which can be of any suitable material as appropriate to construct a fuel cartridge of the present invention. Such materials include, but are not limited to, metals and plastics. Within the housing are a fuel storage chamber 104 separated from a hydrogen storage chamber 106 by a movable or flexible partition 108, wherein the partition includes at least one gas permeable membrane 110.
• suitable gas permeable membranes include materials that are more permeable to hydrogen than to a liquid, for example water, such as silicon rubber, polyethylene, polypropylene, polyurethane, fluoropolymers or any hydrogen- permeable metal membranes such as palladium-gold alloys.
• Suitable gas permeable membranes may be microporous and hydrophobic and/or oleophobic.
• the flexible or movable nature of the partition accommodates volume expansion and reduction and thus pressure changes within the two storage regions.
• the terms “chamber” and “region” are used interchangeably herein.
• the hydrogen storage chamber is maintained at a lower pressure than the fuel storage chamber such that a pressure differential is maintained between the two chambers.
• pressure differentials can be realized by maintaining regions within the system at different pressures.
• the fuel reservoir may be under pressure due to the compression of elastic walls or the application of applied force by a spring plate, for example.
• Hydrogen produced from the fuel solution contained within fuel storage chamber 104 can be forced though the gas permeable membrane into the hydrogen storage chamber by the higher pressure in the fuel storage chamber.
• the pressure differential between the two chambers can be maintained by the removal of hydrogen from the hydrogen storage chamber, such as via a pressure relieve valve that vents at a preset pressure below the pressure in the fuel storage chamber, or the consumption of hydrogen by a hydrogen device or removal of hydrogen from chamber 106 via hydrogen outlet 112.
• a region of lower pressure may be created by the operation of the fuel cell to help ensure the pressure differential.
• This arrangement allows chamber 106 to be vented to a lower pressure to create the pressure differential needed for efficient removal of hydrogen from the fuel solution.
• the hydrogen storage chamber can be vented directly to the atmosphere through hydrogen outlet 112 which can include a check valve to prevent the backflow of air.
• hydrogen outlet 112 can be connected to a hydrogen outlet line 120 downstream from the pressure drop in order to capture the off-gassed hydrogen gas for delivery to the hydrogen device, such as a power module.
• An illustrative example of such a connection is shown in Figure IB, wherein hydrogen outlet 112 is connected to hydrogen line 120 downstream of regulator 124, which receives hydrogen generated from the reaction of the hydrogen generation fuel in reaction chamber 116.
• the regulator 124 may be replaced by the use of an orifice or other flow restrictor that would impart a pressure drop in line 120
• One or more pressure relief valves that vent to a lower pressure such as the atmosphere may be incorporated in the system to remove accumulated hydrogen gas for those instances when the system is inactive for extended periods.
• a fuel regulator controller 122 such as a fuel pump causes the fuel solution to be transported from the fuel storage chamber 104 through fuel conduit 114 to a reaction chamber 116 which contains a catalyst to enhance the reaction of the fuel solution to produce hydrogen gas as shown in Equation 1 for borohydrides.
• the product stream comprising a boron product material and hydrogen gas is transported to a hydrogen separation chamber 118 to separate the gas from liquid and solid components of the product stream and deliver the gas.
• the gas may be delivered for use by a power module comprising a fuel cell or hydrogen-burning engine for conversion to energy, or any other hydrogen device, including balloons or hydrogen storage devices such as a hydrogen cylinders or metal hydrides.
• At least one pressure relief valve may be included in chamber 118 or in the conduit line 120 to vent hydrogen.
• the reaction chamber used with this embodiment preferably contains a reagent, such as a catalyst metal supported on a substrate.
• a reagent such as a catalyst metal supported on a substrate.
• a reagent such as a catalyst metal supported on a substrate.
• the preparation of such supported catalysts is taught, for example, in U.S. Patent No. 6,534,033 entitled "System for Hydrogen Generation.”
• Other suitable catalysts or reagents that are known to promote the reaction of boron hydride compounds such as unsupported metals, acids, or heat can alternatively be present in the reaction chamber.
• These catalysts and reagents can be combined to work in concert for the production of hydrogen; for example, heat may be used with a supported metal catalyst system.
• FIG. 2 illustrates another configuration of a fuel container in accordance with the present invention, wherein features that are the same as those shown in Figure 1 have like numbering.
• the fuel storage chamber 104 is a flexible liquid-tight material, such as, but not limited to: nylon; polyurethane; polyvinylchloride (PVC); polyethylene polymers, including such as low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE), and ethylene-vinyl acetate copolymers (EVA); natural rubber; synthetic rubber; metal foil or other material, and which contains at least one gas permeable membrane.
• LDPE low density polyethylene
• LLDPE linear low density polyethylene
• HDPE high density polyethylene
• EVA ethylene-vinyl acetate copolymers
• the gas permeable membrane is preferably substantially impermeable to liquids and solids, and substantially prevents solid and liquid materials from passing through the gas permeable membrane while allowing gas flow.
• substantially in this context what is meant is preferentially allowing passage of gases relative to the passage of solids and/or liquids or, in preferred cases, allowing passage only of gases.
• the flexible fuel storage chamber 104 is contained within the outer housing as illustrated in Figure 2; the region bounded by and between the outer housing and the fuel chamber comprises the hydrogen storage chamber 106. The flexible walls of the fuel chamber accommodate the pressure changes of the two storage regions.
• a hydrogen gas generation system 300 includes an outer housing 102, which contains a flexible fuel storage chamber 104 enclosed within a flexible hydrogen storage chamber 106, and a hydrogen separation chamber 302.
• the hydrogen separation chamber 302 may be the interior of the housing as shown in Figure 3A, or may be a separate flexible chamber as shown in Figure 3B.
• One or more of the various chambers may be comprised of a flexible, liquid-tight material, such as nylon; polyurethane; polyvinylchloride; polyethylene polymers including, such as, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE), and ethylene-vinyl acetate copolymers (EVA); natural rubber; synthetic rubber; metal foil or other material, or may be comprised of a non- flexible or rigid material, such as metal or plastic, which contains one or more movable partitions telescopically or otherwise to provide for a volume exchanging configuration.
• the fuel storage chamber 104 contains at least one gas permeable membrane.
• the hydrogen generation reaction results in the generation of hydrogen gas and a boron product material which are transported to the hydrogen separation chamber 302 via conduit 304.
• a borate salt is included in the product material.
• the hydrogen and product materials collect in the interior of the housing, i.e., the hydrogen separation chamber 302, and the hydrogen is delivered through at least one hydrogen separation membrane 110 present in the inlet of hydrogen line 120 while maintaining any solid and liquid components of the product mixture within the hydrogen separation chamber 302.
• the hydrogen can be delivered for use by a power module, comprising a fuel cell or hydrogen-burning engine for conversion to energy, or other hydrogen device.
• the hydrogen and boron product materials collect in the flexible hydrogen separation chamber 302.
• the hydrogen is delivered through a hydrogen separation membrane 110 present in the wall of chamber 302 while maintaining any solid and liquid components of the product mixture within the hydrogen separation chamber 302.
• the hydrogen collects in the interior of the housing and can be drawn off through hydrogen gas outlet 306 for use by a power module, comprising a fuel cell or hydrogen-burning engine for conversion to energy, or other hydrogen device.
• the hydrogen generation system of Figures 3A and 3B are preferably operated in a volume exchanging manner, such that initially a full fuel storage chamber surrounded by the hydrogen storage bag occupies the majority of the housing's interior volume.
• a full fuel storage chamber surrounded by the hydrogen storage bag occupies the majority of the housing's interior volume.
• the hydrogen gas and boron reaction products such as borate compounds are transferred to the hydrogen separation chamber 302.
• the reaction products will occupy the volume once occupied by fuel.
• the hydrogen separation chamber or bag may constitute a majority of the interior volume.
• the hydrogen separation chamber 302 encloses the fuel storage chamber and hydrogen storage chamber, wherein features that are the same as those shown in previous figures have like numbering. Such a system maximizes volumetric efficiency, operates in a volume exchanging manner, and can be operated in an orientation independent manner.
• the hydrogen separation chamber may wholly, as shown in Figure 4A, or partially, as shown in Figure 4B, enclose the fuel storage and hydrogen storage chambers.
• Fuel pump 502 conveys fuel from the fuel storage chamber 104 via fuel conduit 114 to reaction chamber 504.
• the product stream comprising hydrogen gas and boron reaction products such as borate compounds, is transported from the outlet of the reaction chamber to hydrogen separation chamber 302 via conduit 304.
• hydrogen gas outlet 306 could be connected directly to the hydrogen separation chamber 302, and at least one hydrogen separation membrane 110 present in the inlet of the gas line 306 would maintain any solid and liquid components of the product mixture within the hydrogen separation chamber 302.
• Any accumulated hydrogen in the hydrogen storage chamber 106 can be provided to the device or power module via an optional regulator 506 which connects hydrogen conduits 112 and 306, or it may simply be vented from the system.
• the hydrogen is withdrawn from both hydrogen storage chamber 106 and hydrogen separation chamber 302 at the same time; that is, both regions feed the hydrogen consuming device at once.
• hydrogen may be variably withdrawn from first one region and then the other.
• the fuel container system of Figure 4 was constructed from a set of three bags that were constructed of 2 mil polyurethane (Stevens Urethane P/N ST-1522F3).
• the fuel storage chamber 104 and hydrogen separation chamber 302 each contained 19.2 cm 2 of polytetrafluoroethylene membrane (Gore, Inc.) capable of allowing the passage of hydrogen while providing a barrier to solids and liquids.
• the three bags were contained within a copper-plated aluminum housing 102 that was hermetically sealed and fitted with a hydrogen outlet and pressure relief valves.
• the inner bag 104 was charged with a solution of 20% by weight sodium borohydride and 3% by weight sodium hydroxide in water (the fuel solution).
• the hydrogen storage bag surrounding the inner fuel bag was connected to atmospheric pressure.
• the solution was pumped through a reaction chamber containing a hydrogen generation catalyst to produce a product stream comprising borate compounds, water, and hydrogen.
• the product stream was transferred into outer hydrogen separation chamber 302 while the hydrogen generation system was held at a pressure between 5 to 7 psig.
• Hydrogen was separated from the liquid and solid products by allowing the gas to pass through the membrane in bag 302 into the interior of the aluminum housing. Due to the exothermicity of the hydrogen generation reaction, the product stream is at a higher temperature than the fuel solution. As the product stream filled bag 302, heat was transferred to the fuel solution in bag 104, and, as the fuel solution warmed, a portion of the fuel underwent hydrolysis, releasing hydrogen into inner bag 104. This hydrogen passed from the bag 104 through its membrane to hydrogen storage bag 106 and vented from the box at atmospheric pressure via outlet 112. The hydrogen produced through reaction with the hydrogen generation catalyst in the reaction chamber was monitored with a mass flow controller external to the hydrogen generation system. From 800 mL of fuel solution, 425 cc/min of hydrogen were produced over continuous operation of the system for 17 hours.
• reaction chamber may be incorporated within the outer housing; in such cases, the appropriate fuel and product conduit lines would not exit the outer housing.
• Additional components of the exemplary hydrogen generation systems such as regulators and fuel pumps may also be incorporated within the outer housing.
• the outer rigid housing 102 can be replaced with a flexible housing to eliminate the weight of an outer container, and increase the energy density of the system.
• Elements such as pistons or springs that apply pressure mechanically may be incorporated into some aspects to push against one or both of chambers 104 and 106 to assist in maintaining a pressure differential and/or drive the fuel into the reactor.

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• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
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• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• General Chemical & Material Sciences (AREA)
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• Separation Using Semi-Permeable Membranes (AREA)

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• 2006
  • 2006-01-27 EP EP06849344A patent/EP1851813A2/en not_active Withdrawn
  • 2006-01-27 JP JP2007555120A patent/JP2008528438A/ja active Pending
  • 2006-01-27 WO PCT/US2006/002895 patent/WO2007084142A2/en active Application Filing
  • 2006-01-27 CN CNA2006800098412A patent/CN101208261A/zh active Pending
  • 2006-01-27 CA CA002600920A patent/CA2600920A1/en not_active Abandoned
  • 2006-01-27 KR KR1020077019318A patent/KR20070106737A/ko not_active Application Discontinuation

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