Ammonia boiler for real-time cracking of ammonia fuel by using plasma based on energy storage of molten salt
Technical Field
The invention belongs to the technical field of new energy boilers, and particularly relates to an ammonia boiler for cracking ammonia fuel in real time by using plasma based on energy storage of molten salt, in particular to an ammonia boiler for cracking ammonia fuel in real time and on line, igniting and supporting combustion by using plasma based on magnetic ring enhanced rotating arc.
Background
Most of the current civil and industrial boilers use fossil fuels for combustion, but CO generated in the combustion process of the fossil fuels2Causing significant greenhouse effect, whether coal or natural gas, the emission of carbon dioxide from boilers contributes a significant portion of the greenhouse effect. If the greenhouse effect is to be reduced, a new fuel is adopted to replace or partially replace the existing fossil fuel, the hydrogen energy is used as clean energy, the combustion process is stable, the calorific value released by combustion is high, and the storage and transportation problems of the hydrogen energy cannot be effectively solved all the time.
The ammonia can be used as a good hydrogen storage medium, greenhouse gases cannot be generated in the combustion process, the octane number of the ammonia fuel is very high, so that the explosion-proof performance of the ammonia fuel is excellent, and the ammonia fuel has excellent safety performance.
And how to recycle the generated waste heat or store the heat energy by the waste heat after the ammonia boiler is combusted and utilized so as to further utilize the energy generated by combustion and improve the energy utilization rate.
Disclosure of Invention
The invention aims to provide an ammonia boiler for cracking ammonia fuel in real time by magnetic ring enhanced rotating arc plasma based on molten salt energy storage, so as to provide the ammonia fuel without carbon emission for the boiler and solve the problems of unstable combustion, insufficient combustion and the like of the ammonia fuel.
In order to solve the technical problems, the invention is realized by the following technical scheme:
the invention relates to an ammonia boiler for cracking ammonia fuel in real time by using plasma based on energy storage of molten salt, which comprises an ammonia decomposition box, wherein the ammonia decomposition box comprises a plasma generator, a temperature sensor, a gas pressure sensor and a hydrogen component sensor; the ammonia fuel source and the air source, the ammonia fuel source heats and decomposes the ammonia fuel source on line in real time through the ammonia decomposition box before being mixed and combusted with the air source; a plasma igniter comprising an electric spark plasma generator; the plasma combustion-supporting device comprises a microwave plasma generator; wherein, the plasma igniter and the plasma combustion-supporting device are arranged in a combustion chamber of the ammonia boiler; the control system, the signal that real-time control system controlled includes: the pressure signal of a gas pressure sensor, the signal of a hydrogen component sensor of an ammonia fuel cracking box, the temperature signal of an air inlet temperature sensor and the steam pressure signal of an outlet of an ammonia boiler.
As a preferred technical scheme of the invention, the liquid ammonia fuel is vaporized or the ammonia fuel enters the ammonia decomposition tank in a gaseous form to be immediately decomposed into mixed gas of ammonia and hydrogen on line; the decomposition rate of the ammonia gas is controlled by the input power of the plasma generator, the decomposition temperature and the catalyst; the plasma input power of the ammonia decomposition tank is controlled by a control system.
As a preferred technical scheme of the invention, the plasma generator is a magnetic ring enhanced rotating arc type plasma generator or an array type plasma generator.
As a preferred technical scheme of the invention, the overall structure of the magnetic ring enhanced rotary arc type plasma generator adopts a coaxial structure; the magnetic ring enhanced rotary arc plasma generator comprises a high-voltage electrode, a magnetic ring, a cyclone ring, a ground electrode and a nozzle; the high-voltage electrode is of a rod-shaped structure, the ground electrode is of a tapered tubular structure, and the nozzle is of a conical structure; the magnetic ring, the high-voltage electrode, the ground electrode and the nozzle are fixed in a coaxial mode in space; the high-voltage electrode and the nozzle are respectively and fixedly connected with the ground electrode.
In a preferred embodiment of the present invention, the nozzle is provided with a constriction device.
In a preferred embodiment of the present invention, the plasma generator includes an ammonia decomposition catalyst disposed in a plasma discharge region.
In a preferred embodiment of the present invention, the ammonia decomposition catalyst includes one or two or more of Ru, Rh, Ni, Co, Ir, Fe, Pt, Cr, and Pd.
In a preferred embodiment of the present invention, the air source further includes an air compressor for increasing a mixing ratio of air and fuel at the air inlet.
As a preferable technical scheme of the invention, the waste heat after the combustion of the ammonia boiler is connected into heat storage equipment or power generation equipment.
As a preferred technical solution of the present invention, the control system comprises the following control steps:
SS01 fuel split setting step: setting plasma radio frequency power in a setting unit of a control system according to a hydrogen component sensor signal in an ammonia decomposition tank or a preset ammonia fuel hydrogen proportion;
optimizing microwave power of a combustion chamber of an SS02 boiler: when the ammonia boiler burns, the control system controls the microwave plasma input power according to the set fuel composition and the values of the air inlet pressure sensor, the air inlet temperature sensor and the steam outlet pressure.
As a preferred technical scheme of the invention, the heat storage equipment comprises a cold molten salt storage tank, a low-temperature molten salt pump, a hot molten salt storage tank, a high-temperature molten salt pump, a first heat exchanger, a second heat exchanger, a steam drum, a third heat exchanger and a fourth heat exchanger; the waste heat after the ammonia boiler burns heats the fused salt with the fused salt in the cold fused salt storage tank through heat conduction, a plurality of pipelines penetrate through the periphery of the cold fused salt storage tank, one end of each pipeline is introduced into the waste heat after the ammonia boiler burns, and the other end of each pipeline is converged into tail gas.
The tail gas treatment process comprises the following steps:
firstly, the acidic gas CO is removed by introducing ammonia water2And NO2Then through configuration with detection of NOxConcentration of NOxSensor and NH3Concentration of NH3A sensor;
if the concentration of ammonia is high, the exhaust gas is led into line A for purifying NO by a selective catalytic reduction catalystxTreated to contain a higher concentration of NH3The tail gas is led into an ammonia boiler for reutilization, and part of the tail gas is purified NH3Introducing ammonia water to keep the concentration of the ammonia water at the optimal value for absorbing acid gas;
if the concentration of ammonia is low, it passes through NH in line B equipped with a suitable catalyst3+NOx→N2+H2Reaction of O with NH3And NOxPurification, followed by treatment of purified CO may utilize high temperature water gas shift, low temperature water gas shift and selective oxidation (Pt catalyst);
and detecting tail gas after treatment, directly discharging the tail gas if the concentration of the pollutants meets the discharge requirement, and sending the tail gas into a line B for purification if the concentration of the pollutants does not meet the discharge requirement until the concentration of the pollutants meets the discharge requirement.
In order to solve the problem of hydrogen production by cracking ammonia fuel on line in real time, the ammonia fuel is quickly reformed by utilizing sliding arc plasma or other plasmas, high-energy electrons generated by plasma discharge can break chemical bonds of ammonia molecules to enable the ammonia molecules to be decomposed into atomic hydrogen atoms and nitrogen atoms, and the two hydrogen atoms are combined to generate hydrogen. In order to solve the problem of insufficient combustion of ammonia fuel, the fuel in the combustion chamber is ignited by adopting the electric spark plasma, the voltage loaded on an electric spark discharge electrode can reach more than twenty thousand volts when the electric spark discharge electrode is in no load, the electric spark plasma can be stably generated even if the air pressure in the combustion chamber reaches ten atmospheric pressures, the fuel combustion is supported by adopting the microwave plasma, seed electrons and ions generated by the electric spark plasma can further absorb microwaves, and more free electrons and ions are generated by collision, excitation and ionization so as to generate the microwave plasma.
The invention has the following beneficial effects:
1. the ammonia fuel is quickly reformed by introducing the sliding arc plasma into the feeding pipeline of the ammonia fuel, and the proportion of ammonia gas/hydrogen gas can be accurately adjusted by adjusting the discharge power of the plasma so that the ammonia/hydrogen mixed fuel can be stably combusted in the boiler combustion chamber.
2. The plasma igniter and the plasma combustion-supporting device are arranged in the combustion chamber, so that stable ignition and combustion supporting of the ammonia/hydrogen mixture are realized, and the combustion efficiency and the combustion fullness of the fuel are effectively improved.
3. The invention changes the working gas components of the boiler through the plasma and generates the plasma in the boiler, thereby effectively improving the stability of the ammonia fuel boiler.
Of course, it is not necessary for any product in which the invention is practiced to achieve all of the above-described advantages at the same time.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic diagram of a system for a plasma real-time ammonia-fueled ammonia boiler based on molten salt energy storage;
FIG. 2 is a schematic view of a magnetic ring enhanced rotary arc plasma generator;
FIG. 3 is a schematic diagram of a magnetic ring enhanced rotating arc plasma power supply principle;
FIG. 4 is a schematic structural diagram of a split plasma igniter and combustion improver;
FIG. 5 is a schematic diagram of the structure of an integrated plasma igniter and combustion improver;
FIG. 6 is a schematic diagram of a power supply system for an ammonia-fueled boiler;
FIG. 7 is a flow diagram of an ammonia boiler tail gas treatment process;
FIG. 8 is a schematic diagram of a high-temperature steam molten salt energy storage system generated by waste heat generated after combustion of an ammonia boiler
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example one
Referring to fig. 1-7, the present invention is an ammonia boiler for real-time pyrolysis of ammonia fuel by plasma based on energy storage of molten salt. Wherein the ammonia decomposition box contains a plasma generator, a temperature sensor, a gas pressure sensor and a hydrogen component sensor; the plasma igniter comprises an electric spark plasma generator; the plasma combustion-supporting device comprises a microwave plasma generator; the plasma igniter and the plasma combustion-supporting device are arranged in a combustion chamber of the ammonia boiler.
The ammonia fuel source is heated and decomposed on line in real time through an ammonia decomposition box before being mixed and combusted with an air source; after the liquid ammonia fuel is vaporized or the ammonia fuel enters the ammonia decomposition tank in a gaseous form to be immediately decomposed into mixed gas of ammonia and hydrogen on line; the decomposition rate of the ammonia gas is controlled by the input power of the plasma generator, the decomposition temperature and the catalyst; the plasma input power of the ammonia decomposition tank is controlled by a control system.
The control system, the signal that real-time control system controlled includes: the pressure signal of a gas pressure sensor, the signal of a hydrogen component sensor of an ammonia fuel cracking box, the temperature signal of an air inlet temperature sensor and the steam pressure signal of an outlet of an ammonia boiler.
As shown in fig. 3, the control steps of the control system are as follows:
SS01 fuel split setting step: setting plasma radio frequency power in a setting unit of a control system according to a hydrogen component sensor signal in an ammonia decomposition tank or a preset ammonia fuel hydrogen proportion;
optimizing microwave power of a combustion chamber of an SS02 boiler: when the ammonia boiler burns, the control system controls the microwave plasma input power according to the set fuel composition and the values of the air inlet pressure sensor, the air inlet temperature sensor and the steam outlet pressure.
Example two
As shown in fig. 2, the plasma generator is a sliding arc type plasma generator, and the overall structure of the sliding arc type plasma generator is a coaxial structure;
the sliding arc plasma generator in the ammonia decomposition box comprises a high-voltage electrode, a cyclone ring, a ground electrode and a nozzle; the high-voltage electrode is of a rod-shaped structure, the ground electrode is of a tapered tubular structure, and the nozzle is of a conical structure; the high-voltage electrode, the ground electrode and the nozzle are fixed in a coaxial manner in space; the high-voltage electrode and the nozzle are respectively and fixedly connected with the ground electrode. And a constriction device is provided on the nozzle.
The functional block diagram of the sliding arc plasma power supply is shown in fig. 3, the power supply of the sliding arc plasma power supply is provided by commercial power or a generator, the power supply comprises a rectifying circuit, a filter circuit, an inverter circuit and a resonant circuit, and the output end of the resonant circuit is connected to a high-voltage electrode and a ground electrode of the sliding arc plasma generator.
The spark plasma generator and the microwave plasma generator may be independently distributed in the boiler combustion chamber, i.e. separate ignition plugs, or may be integrated together, i.e. integrated ignition plugs, as shown in fig. 4 and 5, respectively, the spark plasma generator adopts a needle-plate corona discharge structure, and the microwave plasma generator adopts a ring antenna structure.
The power supply system of the boiler is derived from commercial power or a generator and supplies power to four subsystems or components, as shown in fig. 6, namely an ignition plug of a plasma igniter, a combustion plug of a plasma combustion-supporting device, a sliding arc plasma generator and a load.
The plasma generator places an ammonia decomposition catalyst in the plasma discharge region. The ammonia decomposition catalyst comprises one or two or more of Ru, Rh, Ni, Co, Ir, Fe, Pt, Cr and Pd.
EXAMPLE III
The tail gas treatment process flow of the ammonia boiler is shown in figure 7, and the tail gas generated by the ammonia boiler is firstly introduced into ammonia water to remove acid gas CO2And NO2Then through configuration with detection of NOxConcentration of NOxSensor and NH3Concentration of NH3A sensor for introducing the exhaust gas into the line A if the concentration of ammonia is high, and purifying NO by a selective catalytic reduction catalyst (zeolite or vanadium catalyst containing Fe ions and having Si, O, Al as main components, etc.)xTreated to contain a higher concentration of NH3The tail gas is led into an ammonia boiler for reutilization, and part of the tail gas is purified NH3Introducing ammonia water to keep the concentration of the ammonia water at the optimal value for absorbing acid gas; if the concentration of ammonia is low, it passes through NH in line B equipped with a suitable catalyst3+NOx→N2+H2Reaction of O with NH3And NOxPurification and subsequent treatment of purified CO can be achieved by high temperature water gas shift (350 ℃ C., 550 ℃ C., Fe-Cr-O catalyst), low temperature water gas shift (200 ℃ C., 300 ℃ C.)Cu-Zn-Al-O catalyst) and selective oxidation (Pt catalyst), or developing the catalyst by itself, detecting the tail gas after treatment, directly discharging the pollutant if the pollutant concentration meets the discharge requirement, and sending the tail gas into a line B for purification if the pollutant concentration does not meet the discharge requirement until the discharge requirement is met. This step is collectively referred to as the tail gas treatment device.
Example four
The plasma generator adopts an array type plasma generator. The plasma generator places an ammonia decomposition catalyst in the plasma discharge region. The ammonia decomposition catalyst comprises one or two or more of Ru, Rh, Ni, Co, Ir, Fe, Pt, Cr and Pd.
EXAMPLE five
Based on in embodiment one through the fourth, the air source still is equipped with the air compressor machine that is used for improving air and fuel mixture ratio at the income gas port, improves air and fuel mixture ratio through the mode of air compressor machine increase pressure.
EXAMPLE six
Based on the first embodiment to the fifth embodiment, the waste heat generated after the combustion of the ammonia boiler is connected to the heat storage device or the power generation device, the heat storage device can store heat by using the existing molten salt, the waste heat generated after the combustion of the ammonia boiler is used for heating the molten salt to store heat, and the stored heat can be used for power generation or heat supply.
As shown in fig. 8, a high-temperature steam molten salt energy storage system using waste heat generated after combustion of an ammonia boiler mainly comprises a cold molten salt storage tank 1, a low-temperature molten salt pump 2, a hot molten salt storage tank 3, a high-temperature molten salt pump 4, a first heat exchanger 5, a second heat exchanger 6, a steam drum 7, a third heat exchanger 8 and a fourth heat exchanger 9, wherein the waste heat generated after combustion of the ammonia boiler and the molten salt in the cold molten salt storage tank 1 heat the molten salt in a heat conduction manner, a plurality of pipelines penetrate through the periphery of the cold molten salt storage tank 1, one end of each pipeline is introduced into the waste heat generated after combustion of the ammonia boiler, and the other end of each pipeline is converged into tail gas.
The low-temperature molten salt pump 2 and the high-temperature molten salt pump 4 are respectively arranged at the tops of the cold molten salt storage tank 1 and the hot molten salt storage tank 3; the first heat exchanger 5 is connected with the low-temperature molten salt pump 2 and the hot molten salt storage tank 3 to form a molten salt flow channel, and is provided with an external high-temperature steam inlet al and an external high-temperature steam outlet a 2; the second heat exchanger 6, the third heat exchanger 8 and the fourth heat exchanger 9 are sequentially connected in series and connected with the high-temperature molten salt pump 4 and the cold molten salt storage tank 1 to form a molten salt flow channel; the fourth heat exchanger 9, the third heat exchanger 8, the steam drum 7 and the second heat exchanger 6 form a water/steam flow passage, an external supercooled water inlet bl is arranged on the fourth heat exchanger 9, and a high-temperature steam outlet b2 is arranged on the second heat exchanger 6.
The device mainly comprises two working modes of heat storage and heat release. When heat is stored, the low-temperature molten salt of 250 ℃ in the cold molten salt storage tank 1 is conveyed to the first heat exchanger 5 through the low-temperature molten salt pump 2, high-temperature high-pressure steam of 470 ℃ and 50bar flows in from the al port to heat the low-temperature molten salt, the obtained high-temperature molten salt of 450 ℃ flows in the hot molten salt storage tank 3 to be stored, meanwhile, the high-temperature high-pressure steam is cooled into condensate water of 260 ℃ and 50bar, and the condensate water can be recycled as feed water of a boiler of a thermal power plant. When heat is released, the high-temperature molten salt pump 4 sequentially conveys the high-temperature molten salt of 450 ℃ in the high-temperature molten salt storage tank 3 to the second heat exchanger 6, the third heat exchanger 8 and the fourth heat exchanger 9 to realize heat exchange between the high-temperature molten salt and steam/water, and the low-temperature molten salt of 250 ℃ obtained after heat release flows into the cold molten salt storage tank 1 to be stored; in the molten salt heat release process, supercooled water at 200 ℃ and 50bar flows into a fourth heat exchanger 9, a third heat exchanger 8, a steam drum 7 and a second heat exchanger 6 from a bl port in sequence, finally becomes steam at 440 ℃ and 50bar through three processes of preheating, evaporation and overheating respectively, flows out from a b2 port of the second heat exchanger 6, and is conveyed to a steam turbine power generation system of a thermal power plant for cogeneration.
EXAMPLE seven
Based on the first to fifth embodiments, the waste heat after the combustion of the ammonia boiler is connected to the heat storage device or the power generation device, the heat storage device can be an existing steam generator, the steam turbine is driven to generate power by heating the water steam by the waste heat after the combustion of the ammonia boiler, and a power supply system of the boiler is derived from commercial power or the generator to supply power to four subsystems or components, such as an ignition plug of a plasma igniter, a combustion plug of a plasma combustion-supporting device, a sliding arc plasma generator and a load, as shown in fig. 6; the waste heat can be used for heat supply.
In the description herein, references to the description of "one embodiment," "an example," "a specific example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The preferred embodiments of the invention disclosed above are intended to be illustrative only. The preferred embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention. The invention is limited only by the claims and their full scope and equivalents.