A segmented ammonia-hydrogen fuel cell system and method of generating electricity therefrom

Abstract

This invention discloses a segmented ammonia-hydrogen fuel cell system and its power generation method. The system includes a liquid ammonia tank, an evaporator, a first ammonia decomposition reactor, a second ammonia decomposition reactor, an adsorption device, a fuel cell, and a burner. Liquid ammonia enters the first ammonia decomposition reactor via the evaporator. Its decomposed gas outlet is connected to both the second ammonia decomposition reactor and the adsorption device, with the flow direction regulated by control valves. The outlet of the second ammonia decomposition reactor is connected to the adsorption device, which is connected to the anode of the fuel cell. The fuel cell outlet is connected to the burner and the adsorption device, with the burner providing heat to the ammonia decomposition reactor. This invention uses ammonia decomposition reactors of different sizes connected in series. A small amount of ammonia is used to preheat the system, and then the system heat is used to fully decompose and purify the ammonia before it enters the fuel cell. This ensures stable internal temperature and pressure increases, improves operating efficiency, avoids damage from pressure fluctuations, achieves energy self-circulation, and reduces external energy consumption.

Description

Technical Field

[0001] This invention relates to the field of fuel cell equipment technology, specifically to a segmented ammonia-hydrogen fuel cell system and its power generation method. Background Technology

[0002] With the continuous growth of energy demand and the increasing prominence of environmental problems, the development of efficient and clean energy conversion technologies has become a global focus. Fuel cells, as devices that directly convert chemical energy into electrical energy, have broad application prospects in the energy field due to their high efficiency and low emissions. Among them, ammonia-hydrogen fuel cells (AHFCs), using ammonia (NH3) as fuel, have advantages such as high energy density, ease of storage, and transportation, and are gradually becoming a research hotspot. However, traditional ammonia-hydrogen fuel cell systems still face many challenges in practical applications. First, the process of ammonia decomposition to produce hydrogen requires high temperature and a highly efficient catalyst, resulting in high energy consumption and harsh reaction conditions. Second, the mixed gas after ammonia decomposition may contain incompletely decomposed ammonia, directly affecting the performance and lifespan of the fuel cell. Furthermore, uneven distribution of reactants inside the fuel cell, incomplete gas venting, and fluctuations in internal temperature and pressure also affect the fuel cell's operating efficiency. It is difficult to efficiently and stably couple ammonia decomposition with the fuel cell. Summary of the Invention

[0003] To address the shortcomings of existing technologies, such as the difficulty in efficiently and stably coupling ammonia decomposition and fuel cell systems, and the impact on power generation efficiency due to uneven reactant distribution and large temperature and pressure fluctuations during fuel cell operation, this paper provides a segmented ammonia-hydrogen fuel cell system and its power generation method that can operate stably, generate hydrogen efficiently, and effectively adjust and control the internal temperature and pressure of the fuel cell.

[0004] The technical solution adopted by this invention to solve its technical problem is: a segmented ammonia-hydrogen fuel cell system, including a liquid ammonia tank, an evaporator, a first ammonia decomposition reactor, a second ammonia decomposition reactor, a first adsorption device, a second adsorption device, a fuel cell, and a burner; the liquid ammonia tank is connected to the evaporator, and the evaporator is then connected to the first ammonia decomposition reactor; the first ammonia decomposition reactor is composed of multiple sleeves, which are not interconnected and have gaps between them; an induction coil is wound on the outer wall of the outermost sleeve; the decomposition gas outlet of the first ammonia decomposition reactor is connected in series with the ammonia inlet of the second ammonia decomposition reactor; the volume of the first ammonia decomposition reactor is larger than the volume of the second ammonia decomposition reactor; the decomposition gas outlet of the second ammonia decomposition reactor is... The gas outlet is connected to the first adsorption device, which is connected to the anode inlet of the fuel cell. The decomposition gas outlet of the first ammonia decomposition reactor is also directly connected to the second adsorption device, which is also connected to the anode inlet of the fuel cell. A first control valve is provided between the decomposition gas outlet of the first ammonia decomposition reactor and the second ammonia decomposition reactor, and a second control valve is provided between the decomposition gas outlet of the first ammonia decomposition reactor and the second adsorption device. The opening and closing states of the first and second control valves are opposite. The outlet of the fuel cell is connected to both the burner and the first adsorption device. The first and second adsorption devices are connected in series. The combustion outlet of the burner is connected to both the first and second ammonia decomposition reactors.

[0005] Furthermore, the first ammonia decomposition reactor consists of an inner tube and an outer tube nested together, with the inner and outer tubes not communicating with each other and a gap existing between them; one end of the gap between the inner and outer tubes is the ammonia inlet, and the other end is the decomposition gas outlet; an induction coil is spirally wound around the outside of the outer tube; the gap between the inner and outer tubes is filled with an ammonia decomposition catalyst, and the density of the induction coils on the outer tube near the ammonia inlet is greater than the density of the induction coils on the outer tube near the decomposition gas outlet.

[0006] Furthermore, the second ammonia decomposition reactor includes an ammonia gas pipeline and a flue gas pipeline, which are connected to each other; the outlet of the ammonia gas pipeline of the second ammonia decomposition reactor is also connected to a burner; an electric heating device is installed on the ammonia gas pipeline.

[0007] Furthermore, the combustion outlet of the burner is connected to the inner tube, and a fifth control valve is installed between the burner and the inner tube; the combustion outlet of the burner is connected to the flue gas duct, and a sixth control valve is installed between the burner and the flue gas duct; the opening degree of the fifth control valve and the opening degree of the sixth control valve are different.

[0008] Furthermore, the decomposition gas outlet of the first ammonia decomposition reactor is connected to the evaporator, and the flue gas duct of the second ammonia decomposition reactor is connected to the evaporator.

[0009] Furthermore, an ejector is provided at the exhaust end of the fuel cell, which is connected to both the burner and the first purification device; a third control valve is provided between the ejector and the first purification device, and a fourth control valve is provided between the ejector and the second purification device.

[0010] Furthermore, the first purification device and the second purification device are connected together, and the second purification device is then connected to the evaporator; a buffer tank is provided between the second purification device and the fuel cell.

[0011] A method for generating electricity using a segmented ammonia-hydrogen fuel cell system includes the following steps: Step 1: Heating and evaporating liquid ammonia to form ammonia gas; introducing the evaporated ammonia gas into a first ammonia decomposition reactor, where the ammonia gas in the first ammonia decomposition reactor decomposes into a mixed gas containing hydrogen and nitrogen; Step 2: Opening a first control valve and keeping a second control valve closed, introducing the gas decomposed in the first ammonia decomposition reactor into a second ammonia decomposition reactor; the second ammonia decomposition reactor further decomposes the residual ammonia gas in the introduced decomposed gas into hydrogen and nitrogen; Step 3: Introducing a portion of the gas decomposed in the second ammonia decomposition reactor into a burner for combustion, and introducing a portion of the gas decomposed in the second ammonia decomposition reactor into a first purification device for purification; Step 4: Introducing the gas after combustion in the burner into the first ammonia decomposition reactor and the second ammonia decomposition reactor respectively; Step 5: The volume of the gas after combustion entering the second ammonia decomposition reactor is greater than the volume of the gas after combustion entering the first ammonia decomposition reactor; Step 6: The gas purified by the first purification device is introduced into the fuel cell, where the fuel cell converts the chemical energy of the gas into electrical energy; Step 7: The exhaust gas discharged from the fuel cell after power generation is introduced into the burner for combustion; The gas after combustion in the burner is further introduced into the first and second ammonia decomposition reactors; The volume of the gas after combustion entering the second ammonia decomposition reactor is less than the volume of the gas after combustion entering the first ammonia decomposition reactor; Step 8: The first ammonia decomposition reactor continues to decompose ammonia into hydrogen and nitrogen, the second control valve is opened, the first control valve is closed, and the hydrogen and nitrogen after decomposition in the first ammonia decomposition reactor are introduced into the second purification device for purification; The purified hydrogen and nitrogen are then introduced into the fuel cell to continue generating electricity.

[0012] Furthermore, in step four, the high-temperature combustion gas used to heat the first and second ammonia decomposition reactors is introduced into the evaporator; in step six, the exhaust gas emitted after the fuel cell generates electricity is simultaneously introduced into the first purification device for purging; after purging is completed, the purged gas is introduced back into the evaporator.

[0013] This invention discloses a segmented ammonia-hydrogen fuel cell system and its power generation method. It employs two ammonia decomposition reactors of different sizes connected in series. A small amount of ammonia gas is first heated and decomposed, then introduced into the fuel cell at a lower pressure. Subsequently, the heat generated during system operation is used to effectively heat the ammonia decomposition reactors, ensuring complete decomposition of the ammonia gas. After purification, the ammonia gas directly enters the fuel cell. This pre-raising of the internal pressure and temperature of the fuel cell, followed by the purification of the fully reacted decomposed gas at a higher pressure before being introduced into the fuel cell, facilitates a stable increase in internal temperature and pressure, thereby improving the fuel cell's operating efficiency. It also avoids damage to the fuel cell caused by excessive pressure fluctuations. Simultaneously, the system effectively utilizes the gas and corresponding heat generated during operation, achieving energy self-circulation and reducing the consumption and demand for external energy. Attached Figure Description

[0014] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the specific embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the structure of a segmented ammonia-hydrogen fuel cell system according to the present invention. Detailed Implementation

[0016] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] like Figure 1 As shown, the segmented ammonia-hydrogen fuel cell system of the present invention includes a liquid ammonia tank 1, an evaporator 2, a first ammonia decomposition reactor 3, a second ammonia decomposition reactor 4, a first adsorption device 51, a second adsorption device 52, a fuel cell 7, and a burner 9.

[0018] The liquid ammonia tank 1 is connected to the evaporator 2, and the evaporator 2 is connected to the first ammonia decomposition reactor 3. The first ammonia decomposition reactor 3 is composed of multiple sleeves, which are not interconnected and have gaps between them. An induction coil is wound on the outer wall of the outermost sleeve. The decomposition gas outlet of the first ammonia decomposition reactor 3 is connected in series with the ammonia inlet of the second ammonia decomposition reactor 4. The volume of the first ammonia decomposition reactor 3 is larger than the volume of the second ammonia decomposition reactor 4. The decomposition gas outlet of the second ammonia decomposition reactor 4 is connected to the first adsorption device 51, and the first adsorption device 51 is connected to the anode inlet of the fuel cell 7.

[0019] The decomposition gas outlet of the first ammonia decomposition reactor 3 is also directly connected to the second adsorption device 52, and the second adsorption device 52 is also connected to the anode inlet of the fuel cell 7; a first control valve 41 is provided between the decomposition gas outlet of the first ammonia decomposition reactor 3 and the second ammonia decomposition reactor 4, and a second control valve 53 is provided between the decomposition gas outlet of the first ammonia decomposition reactor 3 and the second adsorption device 52; the opening and closing states of the first control valve 41 and the second control valve 53 are opposite.

[0020] The outlet of the fuel cell 7 is connected to both the burner 9 and the first adsorption device 51; the first adsorption device 51 and the second adsorption device 52 are connected in series; the combustion outlet of the burner 9 is connected to both the first ammonia decomposition reactor 3 and the second ammonia decomposition reactor 4.

[0021] like Figure 1As shown, liquid ammonia in the liquid ammonia tank 1 enters the evaporator 2 for heating and evaporation; ammonia gas is formed after evaporation in the evaporator 2; the vaporized ammonia gas enters the first ammonia decomposition reactor 3 for ammonia decomposition; wherein, the first ammonia decomposition reactor 3 is a sleeve-type structure, consisting of an inner tube and an outer tube nested together, the inner tube and the outer tube are not connected to each other, and there is a gap between the inner tube and the outer tube; one end of the gap between the inner tube and the outer tube is the ammonia gas inlet, and the other end of the gap between the inner tube and the outer tube is the decomposition gas outlet, and an induction coil is spirally wound on the outside of the outer tube; the ammonia gas after evaporation in the evaporator 2 enters the gap between the inner tube and the outer tube; and flows through the gap between the inner tube and the outer tube before being discharged; an ammonia decomposition reaction occurs in the gap between the inner tube and the outer tube, generating a mixed gas of hydrogen, nitrogen and a small amount of ammonia; wherein, the induction coil is electrically connected to an external power source; when When the induction coil is energized, electromagnetic induction occurs inside the outer tube, including inside the inner tube and the gap between the inner and outer tubes, generating heat to heat the gas inside the outer tube. By setting up a sleeve-type structure consisting of an inner and outer tube with a gap between them, ammonia gas flows through the gap between the inner and outer tubes and is eventually discharged. This facilitates the maximum transfer of heat generated by electromagnetic induction to the ammonia gas, allowing the ammonia gas to effectively absorb heat and undergo a decomposition reaction. To enable rapid ammonia decomposition and improve ammonia decomposition efficiency, preferably, the gap between the inner and outer tubes is filled with an ammonia decomposition catalyst. The density of the induction coils on the outer tube near the ammonia inlet is greater than the density on the outer tube near the decomposed gas outlet, to better match the ammonia concentration between the outer and inner tubes, allowing the ammonia gas to uniformly absorb heat and decompose in the first ammonia decomposition reactor 3, thus improving the decomposition efficiency and effect of ammonia.

[0022] The gap between the inner and outer pipes of the first ammonia decomposition reactor 3 is connected to the ammonia inlet of the second ammonia decomposition reactor 4. A first control valve 41 is provided between the first ammonia decomposition reactor 3 and the second ammonia decomposition reactor 4. Preferably, the second ammonia decomposition reactor 4 includes an ammonia pipeline and a flue gas pipeline, which are fitted together. One end of the ammonia pipeline is a second ammonia inlet and is connected to the first ammonia decomposition reactor 3, and the other end of the ammonia pipeline is a second decomposition gas outlet and is connected to the first purification device 51. A mixture of hydrogen and nitrogen introduced from the first ammonia decomposition reactor 3 enters the second ammonia decomposition reactor 4. Further heating and decomposition are carried out in the mixture to further decompose the residual ammonia in the gas mixture, preventing ammonia from entering the fuel cell 7 and improving the purity of the hydrogen subsequently entering the fuel cell 7. Simultaneously, because the volume of the second ammonia decomposition reactor 4 is larger than that of the first ammonia decomposition reactor 3, when gas enters the second ammonia decomposition reactor 4 from the first ammonia decomposition reactor 3, the smaller volume of the second ammonia decomposition reactor 4, combined with the first control valve 41, can buffer the introduced gas, reducing the pressure of the gas subsequently discharged from the second ammonia decomposition reactor 4. Therefore, it reduces the impact of excessive pressure fluctuations inside the fuel cell caused by excessive gas pressure entering the fuel cell. The fuel cell generates electricity effectively. The decomposed gas, after depressurization, enters the first purification device 51 for further adsorption and extraction, ensuring no residual ammonia enters the fuel cell and improving its operational safety. To further ensure the purification effect of the first purification device 51, a first cooling device (not shown) is preferably provided between the first purification device 51 and the second ammonia decomposition reactor 4. This first cooling device cools the gas discharged from the second ammonia decomposition reactor 4 before it enters the first purification device 51 for purification. This also reduces the temperature of the gas entering the fuel cell 7, minimizing instability in fuel cell operation caused by temperature fluctuations. Qualitatively, to better control the temperature and pressure of the gas entering the fuel cell 7 and avoid the impact of excessively high temperature or pressure on the fuel cell, preferably, the outlet of the ammonia pipeline of the second ammonia decomposition reactor 4 is also connected to the burner 9; part of the decomposed gas in the second ammonia decomposition reactor 4 can be introduced into the burner 9 for combustion, which promotes the complete combustion of the burner 9 and provides fuel for the burner 9; at the same time, it reduces the gas content entering the fuel cell 7, thereby avoiding temperature fluctuations inside the fuel cell 7 caused by the introduction of gas with high pressure and temperature; an electric heating device is also provided on the ammonia pipeline of the second ammonia decomposition reactor.

[0023] An ejector 8 is provided at the exhaust end of the fuel cell 7. The ejector 8 is connected to the burner 9 and the first purification device 51. The gas remaining after the fuel cell 7 generates electricity includes water vapor and unreacted hydrogen. Under the ejection action of the ejector 8, the gas can be quickly introduced into the burner 9 to improve the combustion effect of the burner 9. It can also quickly enter the first purification device 51 for purging. By setting the ejector 8, the gas can be quickly discharged from the inside of the fuel cell 7, which is beneficial to reducing the internal pressure of the fuel cell and avoiding damage to the inside of the fuel cell caused by excessive pressure. At the same time, it is also beneficial to the combustion of gas in the burner 9 and the purification of gas in the first purification device 51, thereby improving the operating efficiency of the system. A third control valve and a fourth control valve are respectively provided between the ejector 8, the first purification device 51, and the burner 9 to adjust the gas flow rate entering the first purification device 51 and the burner 9 through the ejector 8, so as to better control the combustion of the burner 9 and the purification of gas by the first purification device 51.

[0024] The combustion outlet of the burner 9 is connected to the inner tube of the first ammonia decomposition reactor 3 and the flue gas duct of the second ammonia decomposition reactor 4, respectively. The high-temperature combustion gas generated after combustion enters the inner tube of the first ammonia decomposition reactor 3 and the flue gas duct of the second ammonia decomposition reactor 4, respectively, to heat the ammonia in the first ammonia decomposition reactor 3; at the same time, it also heats the decomposition gas in the second ammonia decomposition reactor 4, promoting the endothermic decomposition of the ammonia in the first ammonia decomposition reactor 3 and the residual ammonia in the second ammonia decomposition reactor 4. For the first ammonia decomposition reactor 3, since the combustion gas enters the inner tube and the ammonia flows in the gap between the inner tube and the outer tube, plus the induction coil wound around the outer tube, the ammonia between the inner tube and the outer tube is heated simultaneously from the inside and outside, avoiding the uneven temperature distribution inside the first ammonia decomposition reactor 3 from affecting the heating effect of the ammonia; and promoting the full endothermic decomposition of ammonia.

[0025] In order to achieve the recovery and utilization of energy after ammonia decomposition, reduce the system's energy consumption, and save energy, preferably, the inner tube of the first ammonia decomposition reactor 3 is connected to the evaporator 2, and the outlet of the flue gas pipe of the second ammonia decomposition reactor 4 is connected to the evaporator 2; the heated combustion gas in the inner tube of the first ammonia decomposition reactor 3 and the heated combustion gas in the flue gas pipe of the second ammonia decomposition reactor 4 simultaneously enter the evaporator 2 to further heat the liquid ammonia introduced from the liquid ammonia tank 1, promoting the heating and vaporization of the liquid ammonia in the evaporator 2 to generate ammonia gas; the heated high-temperature combustion gas is discharged from the evaporator 2; since the gas entering the burner is a mixture of hydrogen and nitrogen generated by ammonia decomposition, and unreacted hydrogen and water vapor discharged from the fuel cell outlet, the combustion gas is water vapor and nitrogen, which reduces the risk of greenhouse gas emissions compared to traditional fossil fuels; and greatly improves the environmental protection effect of the system.

[0026] Furthermore, the gap between the inner and outer tubes of the first ammonia decomposition reactor 3 is also connected to the second purification device 52, and a second control valve 53 is provided between the first ammonia decomposition reactor 3 and the second purification device 52. During operation, preferably, the decomposed gas discharged from the first ammonia decomposition reactor 3 preferentially enters the second ammonia decomposition reactor 4 for ammonia decomposition. After some of the ammonia in the second ammonia decomposition reactor 4 is decomposed, it first enters the fuel cell. Since the gas discharged from the first ammonia decomposition reactor 3 undergoes further reaction in the larger second ammonia decomposition reactor 4 and purification by the first purification device 51, and some of the decomposed gas in the second ammonia decomposition reactor 4 can be diverted to the burner 9, the gas pressure and temperature entering the fuel cell can be effectively reduced, avoiding fluctuations inside the fuel cell caused by high-temperature and high-pressure gas directly entering the fuel cell, which would affect the fuel cell's lifespan and operational stability. At the same time, a preheating effect is achieved inside the fuel cell.

[0027] Once sufficient high-temperature combustion gas is generated inside the burner 9, it is gradually introduced into the inner tube of the first ammonia decomposition reactor 3 to increase the heating of the ammonia inside the reactor 3. Then, the second control valve 53 is opened to directly introduce the decomposed gas from the first ammonia decomposition reactor 3 into the second purification device 52 for purification. Afterward, the gas is introduced into the buffer tank 6 connected to the second purification device 52 for pressure adjustment before entering the fuel cell for power generation. This gradually increases the pressure of the gas entering the fuel cell 7, which helps to improve the electrochemical reaction rate and battery voltage inside the fuel cell, thereby improving the fuel cell output efficiency. During operation, the pressure adjustment inside the fuel cell 7, combined with the ejector 8 at the tail of the fuel cell 7, can also prevent damage caused by excessive pressure.

[0028] A fifth control valve 91 is provided between the burner 9 and the inner tube, and a sixth control valve 92 is provided between the burner 9 and the second ammonia decomposition reactor 4. The fifth control valve 91 and the sixth control valve 92 are opened simultaneously, with different opening degrees for each. This allows the gases generated during combustion to be introduced simultaneously but in different amounts into the first ammonia decomposition reactor 3 and the second ammonia decomposition reactor 4. Specifically, during the system startup phase, the opening degree of the fifth control valve 91 is less than that of the sixth control valve 92, so that most of the high-temperature gases after combustion are first introduced into the second ammonia decomposition reactor 4. This ensures that the second ammonia decomposition reactor 4 has sufficient heat to remove residual ammonia from the mixed gas as much as possible, and also effectively preheats the first ammonia decomposition reactor 3. After the fuel cell heating is complete, the opening degree of the fifth control valve 91 is greater than that of the sixth control valve 92. The opening degree allows most of the high-temperature flue gas after combustion to be first introduced into the first ammonia decomposition reactor 3 for reaction, so that the ammonia gas can fully react in the first ammonia decomposition reactor 3 to generate hydrogen and nitrogen gas. After the mixed gas is purified by adsorption, it can enter the fuel cell, gradually increasing the gas pressure inside the fuel cell and promoting the power generation efficiency of the fuel cell. In order to further utilize the gas and its heat during the system operation, preferably, the first purification device 51 and the second purification device 52 are connected, and the second purification device 52 is connected to the evaporator 2. The exhaust gas after the fuel cell power generation introduced from the ejector 8 enters the second purification device 52 for further purging after the first purification device 51 is purged, and at the same time, the purification device is purged and desorbed, improving the operating efficiency of the system. The purged gas enters the evaporator 2, and its remaining heat is used to continue heating the liquid ammonia in the evaporator 2, improving the energy utilization rate of the system.

[0029] This application also discloses a method for generating electricity using the segmented ammonia-hydrogen fuel cell system, comprising the following steps:

[0030] Step 1: Heating and evaporating liquid ammonia to form ammonia gas; introducing the evaporated ammonia gas into the first ammonia decomposition reactor, where the ammonia gas in the first ammonia decomposition reactor decomposes the ammonia gas into a mixed gas containing hydrogen and nitrogen;

[0031] Step 2: Open the first control valve and keep the second control valve closed to introduce the gas decomposed in the first ammonia decomposition reactor into the second ammonia decomposition reactor; the second ammonia decomposition reactor further decomposes the residual ammonia in the introduced decomposed gas into hydrogen and nitrogen.

[0032] Step 3: Part of the gas decomposed by the second ammonia decomposition reactor is introduced into the burner for combustion, and part of the gas decomposed by the second ammonia decomposition reactor is introduced into the first purification device for purification.

[0033] Step 4: The combusted gas from the burner is introduced into the first ammonia decomposition reactor and the second ammonia decomposition reactor respectively; the volume of the combusted gas entering the second ammonia decomposition reactor is greater than the volume of the combusted gas entering the first ammonia decomposition reactor.

[0034] Step 5: The gas purified by the first purification device is introduced into the fuel cell, where the fuel cell converts the chemical energy of the gas into electrical energy;

[0035] Step Six: The exhaust gas emitted after the fuel cell generates electricity is introduced into the burner for combustion; the gas after combustion in the burner is then introduced into the first ammonia decomposition reactor and the second ammonia decomposition reactor; the volume of the gas after combustion entering the second ammonia decomposition reactor is smaller than the volume of the gas after combustion entering the first ammonia decomposition reactor.

[0036] Step 7: The first ammonia decomposition reactor continues to decompose ammonia into hydrogen and nitrogen. The second control valve is opened and the first control valve is closed. The hydrogen and nitrogen decomposed by the first ammonia decomposition reactor are introduced into the second purification device for purification. The purified hydrogen and nitrogen are then introduced into the fuel cell to continue generating electricity.

[0037] In step four, the high-temperature combustion gas used to heat the first and second ammonia decomposition reactors is introduced into the evaporator to heat the liquid ammonia. In step six, the exhaust gas emitted after the fuel cell generates electricity is simultaneously introduced into the first purification device, and the exhaust gas is used to purge the first and second purification devices in sequence. After purging, the purged gas is introduced into the evaporator to continue heating the liquid ammonia, thereby improving the energy utilization rate of the system.

[0038] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A segmented ammonia-hydrogen fuel cell system, comprising a liquid ammonia tank, an evaporator, a first ammonia decomposition reactor, a second ammonia decomposition reactor, a first adsorption device, a second adsorption device, a fuel cell, and a burner; characterized in that: The liquid ammonia tank is connected to the evaporator, which is in turn connected to the first ammonia decomposition reactor. The first ammonia decomposition reactor is composed of multiple sleeves, which are not interconnected and have gaps between them. An induction coil is wound around the outer wall of the outermost sleeve. The decomposition gas outlet of the first ammonia decomposition reactor is connected in series with the ammonia inlet of the second ammonia decomposition reactor. The volume of the first ammonia decomposition reactor is larger than that of the second ammonia decomposition reactor. The decomposition gas outlet of the second ammonia decomposition reactor is connected to the first adsorption device, which is connected to the anode inlet of the fuel cell. The decomposition gas outlet of the first ammonia decomposition reactor is also directly connected to the second adsorption device, and the second adsorption device is also connected to the anode inlet of the fuel cell; a first control valve is provided between the decomposition gas outlet of the first ammonia decomposition reactor and the second ammonia decomposition reactor, and a second control valve is provided between the decomposition gas outlet of the first ammonia decomposition reactor and the second adsorption device; the opening and closing states of the first control valve and the second control valve are opposite. The outlet of the fuel cell is connected to both the burner and the first adsorption device; the first adsorption device and the second adsorption device are connected in series; the combustion outlet of the burner is connected to both the first ammonia decomposition reactor and the second ammonia decomposition reactor.

2. The segmented ammonia-hydrogen fuel cell system according to claim 1, characterized in that: The first ammonia decomposition reactor consists of an inner tube and an outer tube nested together, with the inner and outer tubes not communicating with each other and a gap existing between them. One end of the gap between the inner and outer tubes is the ammonia inlet, and the other end is the decomposition gas outlet. An induction coil is spirally wound around the outside of the outer tube. The gap between the inner and outer tubes is filled with an ammonia decomposition catalyst. The density of the induction coils on the outer tube near the ammonia inlet is greater than the density of the induction coils on the outer tube near the decomposition gas outlet.

3. A segmented ammonia-hydrogen fuel cell system according to claim 2, characterized in that: The second ammonia decomposition reactor includes an ammonia gas pipeline and a flue gas pipeline, which are connected to each other; the outlet of the ammonia gas pipeline of the second ammonia decomposition reactor is also connected to the burner; an electric heating device is installed on the ammonia gas pipeline.

4. A segmented ammonia-hydrogen fuel cell system according to claim 3, characterized in that: The combustion outlet of the burner is connected to the inner tube, and a fifth control valve is provided between the burner and the inner tube; the combustion outlet of the burner is connected to the flue gas duct, and a sixth control valve is provided between the burner and the flue gas duct; the opening degree of the fifth control valve and the opening degree of the sixth control valve are different.

5. A segmented ammonia-hydrogen fuel cell system according to claim 3, characterized in that: The decomposition gas outlet of the first ammonia decomposition reactor is connected to the evaporator, and the flue gas duct of the second ammonia decomposition reactor is connected to the evaporator.

6. A segmented ammonia-hydrogen fuel cell system according to claim 1, characterized in that: An ejector is provided at the exhaust end of the fuel cell, and the ejector is connected to both the burner and the first purification device. A third control valve is provided between the ejector and the first purification device, and a fourth control valve is provided between the ejector and the second purification device.

7. A segmented ammonia-hydrogen fuel cell system according to claim 6, characterized in that: The first purification device is connected to the second purification device, and the second purification device is then connected to the evaporator; a buffer tank is provided between the second purification device and the fuel cell.

8. A method for generating electricity using a segmented ammonia-hydrogen fuel cell system according to any one of claims 1 to 7, characterized in that: Includes the following steps: Step 1: Heating and evaporating liquid ammonia to form ammonia gas; introducing the evaporated ammonia gas into the first ammonia decomposition reactor, where the ammonia gas in the first ammonia decomposition reactor decomposes the ammonia gas into a mixed gas containing hydrogen and nitrogen; Step 2: Open the first control valve and keep the second control valve closed to introduce the gas decomposed in the first ammonia decomposition reactor into the second ammonia decomposition reactor; the second ammonia decomposition reactor further decomposes the residual ammonia in the introduced decomposed gas into hydrogen and nitrogen. Step 3: Part of the gas decomposed by the second ammonia decomposition reactor is introduced into the burner for combustion, and part of the gas decomposed by the second ammonia decomposition reactor is introduced into the first purification device for purification. Step 4: The combusted gas from the burner is introduced into the first ammonia decomposition reactor and the second ammonia decomposition reactor respectively; the volume of the combusted gas entering the second ammonia decomposition reactor is greater than the volume of the combusted gas entering the first ammonia decomposition reactor. Step 5: The gas purified by the first purification device is introduced into the fuel cell, where the fuel cell converts the chemical energy of the gas into electrical energy; Step Six: The exhaust gas emitted after the fuel cell generates electricity is introduced into the burner for combustion; the gas after combustion in the burner is then introduced into the first ammonia decomposition reactor and the second ammonia decomposition reactor; the volume of the gas after combustion entering the second ammonia decomposition reactor is smaller than the volume of the gas after combustion entering the first ammonia decomposition reactor. Step 7: The first ammonia decomposition reactor continues to decompose ammonia into hydrogen and nitrogen. The second control valve is opened and the first control valve is closed. The hydrogen and nitrogen decomposed by the first ammonia decomposition reactor are introduced into the second purification device for purification. The purified hydrogen and nitrogen are then introduced into the fuel cell to continue generating electricity.

9. A power generation method according to claim 8, characterized in that: In step four, the high-temperature combustion gas used to heat the first and second ammonia decomposition reactors is introduced into the evaporator; in step six, the exhaust gas emitted after the fuel cell generates electricity is simultaneously introduced into the first purification device for purging; after purging, the purged gas is introduced back into the evaporator.

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