A multi-stage solid-state hydrogen storage system and method for SOFC

Abstract

The present invention discloses a multi-stage solid-state hydrogen storage system and method for SOFC, comprising a gaseous hydrogen storage device and an air conveying device; the gaseous hydrogen storage device is connected to the SOFC and a combustion device via a hydrogen reheater; the air conveying device is connected to an air supply device, the end of which is connected to the air reheater via an air heat recovery device, and the air reheater is connected to the SOFC; multiple hydrogen storage reactors are installed between the gaseous hydrogen storage device and the hydrogen reheater, and the hydrogen storage reactors include a TiFe reactor, a Mg2Ni reactor, and a TiH2 reactor, which are sequentially connected. By integrating the SOFC with multi-stage solid-state hydrogen storage, the system provides a safe, high-density, and low-cost hydrogen storage function for the SOFC, while the high-temperature waste heat generated during the SOFC power generation process provides a driving heat source for the solid-state hydrogen storage to release hydrogen, thus resolving the shortcomings of the prior art.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid oxide hydrogen storage, and in particular relates to a multi-stage solid-state hydrogen storage system and method for SOFC. Background Art

[0002] Solid oxide fuel cells (SOFCs) are electrochemical conversion devices that generate electricity by oxidizing fuels. They offer advantages such as high combined heat and power efficiency, fuel flexibility, low emissions, and good electrolysis reversibility. Early SOFC development primarily used natural gas as a fuel. Combined heat and power (CHP) allows for efficient natural gas utilization, making it a popular choice for distributed power and heating applications, such as in homes.

[0003] With the increasing installation of renewable energy sources such as photovoltaics and wind power, intermittent and unstable green electricity is increasingly impacting the power grid. Hydrogen electrolysis is considered an effective means of regulating power. The green hydrogen produced can be widely used in transportation, chemicals, steel, kilns, and other sectors, supporting carbon reduction initiatives in key industries. Highly efficient hydrogen-to-electricity conversion through SOFCs has emerged as a highly promising green hydrogen application, particularly in long-term energy storage, shipping, and data centers.

[0004] Relying on renewable energy from wind and solar power, SOFCs use green hydrogen as a fuel, offering the advantages of large-scale, low-cost production. Green hydrogen also prevents problems like carbon deposits on SOFC electrodes. However, hydrogen is difficult to store and has a wide range of explosive limits, making it difficult to use as a fuel in SOFCs. Furthermore, while solid-state hydrogen storage offers advantages such as safety, high storage density, and low cost, it requires an external heat source to operate during the dehydrogenation process. Currently, no commercially available technology can address these issues. Summary of the Invention

[0005] The purpose of the present invention is to provide a multi-stage solid-state hydrogen storage system and method for SOFC. On the one hand, it is used to solve the technical defects that hydrogen is difficult to store, the explosion limit range is wide, and SOFC is difficult to use hydrogen as a fuel; on the other hand, it is used to solve the technical defect that solid-state hydrogen storage requires an external driving heat source to cooperate in the hydrogen release process.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] In a first aspect, a multi-stage solid-state hydrogen storage system for SOFC is provided, comprising:

[0008] A gaseous hydrogen storage device and an air delivery device; the gaseous hydrogen storage device is connected to the SOFC and the combustion device via a hydrogen reheater; the air delivery device is connected to an air supply device, the end of the air supply device is connected to the air reheating device via an air heat recovery device, and the air reheating device is connected to the SOFC;

[0009] Multiple reactors are installed between the gaseous hydrogen storage device and the hydrogen reheater, and the reactors include a TiFe reactor, a Mg2Ni reactor and a TiH2 reactor. The TiFe reactor, Mg2Ni reactor and TiH2 reactor are connected in sequence.

[0010] Furthermore, a MgH2 reactor is connected between the Mg2Ni reactor and the TiH2 reactor;

[0011] Wherein, the TiFe reactor is a hydrogen storage reactor filled with TiFeMn or TiFe-based metal hydride;

[0012] The Mg2Ni reactor is a hydrogen storage reactor filled with Mg2Ni metal hydride;

[0013] The MgH2 reactor is a hydrogen storage reactor filled with Mg-based metal hydride;

[0014] The TiH2 reactor is a hydrogen storage reactor filled with Ti-based metal hydride;

[0015] A pressure control device is connected between the gaseous hydrogen storage device and the hydrogen reheater, and the pressure control device is used to adjust the pressure of the hydrogen output by the gaseous hydrogen storage device.

[0016] Furthermore, the pressure control device is a pressure control valve.

[0017] Furthermore, the SOFC has an anode end and a cathode end, the hydrogen heat replenisher is connected to the anode end, and the air heat replenisher is connected to the cathode end;

[0018] The anode terminal and the cathode terminal of the SOFC are both connected to a combustion device.

[0019] Furthermore, the combustion device is also connected to a plurality of reactors and an air heat recovery device.

[0020] Furthermore, the air heat recovery device includes a first air heat recovery device and a second air heat recovery device, one end of the first air heat recovery device is connected to the combustion device, and the other end is connected to the second air heat recovery device, and the second air heat recovery device is connected to the air supply device.

[0021] Furthermore, the air supply device is a blower.

[0022] Furthermore, the gaseous hydrogen storage device is a gaseous hydrogen storage tank.

[0023] Furthermore, the air heating device is an air heating device.

[0024] In a second aspect, a method for using a multi-stage solid-state hydrogen storage system for SOFC is provided. The method is performed using the multi-stage solid-state hydrogen storage system as described above, comprising:

[0025] Using a gaseous hydrogen storage device to deliver hydrogen to the SOFC, so that the hydrogen undergoes an electrochemical reaction at the anode end of the SOFC to produce a product of water vapor and unreacted high-temperature hydrogen, i.e., anode tail gas;

[0026] The anode tail gas heats the multi-stage hydrogen storage reactor and is condensed in the final TiFe reactor. The hydrogen is separated and recovered to continue participating in the anode reaction.

[0027] Using an air delivery device, air is delivered to the SOFC, so that the air undergoes an electrochemical reaction at the cathode end of the SOFC while the cathode end of the SOFC discharges excess high-temperature air;

[0028] The remaining high-temperature air is distributed to heat the anode fuel, cathode air, and hydrogen storage reactor;

[0029] When the hydrogen storage reactor or SOFC stack needs further heating, part of the anode tail gas and the remaining high-temperature air are distributed to burn in the burner to supplement the required heat;

[0030] In the SOFC reverse electrolysis mode, an exothermic reaction occurs during the hydrogen absorption process of the multi-stage hydrogen storage reactor, heating room temperature water and providing 700-800°C superheated steam for the electrolytic hydrogen production process.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. The system achieves multi-stage solid-state storage of hydrogen through TiFe reactors, Mg2Ni reactors, and TiH2 reactors, and can effectively store and release hydrogen under different conditions, thereby improving the hydrogen storage capacity and flexibility of the entire system. As the main storage unit for hydrogen, the gaseous hydrogen storage device uses high-pressure technology to achieve efficient storage of hydrogen, while the hydrogen reheater can preheat the hydrogen before it enters the SOFC, increasing the reactivity of hydrogen and thus optimizing the power generation efficiency of the SOFC. Finally, through the integration of SOFC and multi-stage solid-state hydrogen storage, the system provides SOFC with safe, high-density, and low-cost hydrogen storage capabilities. The high-temperature waste heat generated by the SOFC power generation process provides a driving heat source for the release of hydrogen from the solid-state hydrogen storage, thus resolving the defects of the existing technology.

[0033] 2. By adding a MgH2 reactor between the Mg2Ni reactor and the TiH2 reactor, the system achieves a more diversified solid-state hydrogen storage method. As an efficient hydrogen storage material, MgH2 has the advantages of high hydrogen storage density and moderate hydrogen release temperature, which can further improve the system's hydrogen storage capacity and hydrogen release efficiency.

[0034] 3. The pressure control valve enables the system to accurately adjust the hydrogen pressure output by the gaseous hydrogen storage device, which is of great significance for maintaining the stable operation of the system, protecting various components from high-pressure shocks, and optimizing the flow state of hydrogen in the reactor.

[0035] 4. The hydrogen reheater is connected to the anode end of the SOFC, which can preheat the hydrogen entering the SOFC. The preheated hydrogen has higher reactivity and can more fully undergo electrochemical reaction with the oxygen provided by the cathode end, thereby improving the power generation efficiency of the SOFC.

[0036] 5. The heat energy generated by the combustion device can be recovered through the air heat recovery device and used to preheat the air or hydrogen entering the reactor, thereby improving the thermal energy utilization rate of the entire system and reducing energy waste.

[0037] 6. By setting up the first air heat recovery device and the second air heat recovery device, the system realizes multi-stage recovery of the heat energy generated by the combustion device, which can more fully capture and utilize the heat energy and improve the heat energy recovery efficiency of the entire system. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0039] Figure 1 Schematic diagram of the multi-stage solid-state hydrogen storage system for SOFC provided by the present invention;

[0040] Figure 2 A flow chart of the method for using the multi-stage solid-state hydrogen storage system for SOFC provided by the present invention;

[0041] In the figure: 1. Gaseous hydrogen storage device; 2. TiFe reactor; 3. Mg2Ni reactor; 4. MgH2 reactor; 5. TiH2 reactor; 6. Pressure control device; 7. SOFC; 8. Combustion device; 9. Hydrogen reheater; 10. Air reheater; 11. First air heat recovery device; 12. Second air heat recovery device; 13. Air supply device; 14. Air conveying device. DETAILED DESCRIPTION

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0043] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0044] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not require further definition or explanation in subsequent drawings.

[0045] In the description of the embodiments of the present invention, it should be noted that if the terms "upper," "lower," "horizontal," "inner," etc. appear, the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the inventive product is typically placed when in use. These terms are merely for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first," "second," etc. are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0046] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0047] In the description of the embodiments of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0048] Solid oxide fuel cells (SOFCs) are electrochemical conversion devices that generate electricity by oxidizing fuels. They offer advantages such as high combined heat and power efficiency, fuel flexibility, low emissions, and good electrolysis reversibility. Early SOFC development primarily used natural gas as a fuel. Combined heat and power (CHP) allows for efficient natural gas utilization, making it a popular choice for distributed power and heating applications, such as in homes.

[0049] With the increasing installation of renewable energy sources such as photovoltaics and wind power, intermittent and unstable green electricity is increasingly impacting the power grid. Hydrogen electrolysis is considered an effective means of regulating power. The green hydrogen produced can be widely used in transportation, chemicals, steel, kilns, and other sectors, supporting carbon reduction initiatives in key industries. Highly efficient hydrogen-to-electricity conversion through SOFCs has emerged as a highly promising green hydrogen application, particularly in long-term energy storage, shipping, and data centers.

[0050] Relying on renewable energy from wind and solar power, SOFCs use green hydrogen as a fuel, offering the advantages of large-scale, low-cost production. Green hydrogen also prevents problems like carbon deposits on SOFC electrodes. However, hydrogen is difficult to store and has a wide range of explosive limits, making it unsuitable for SOFCs. Furthermore, while solid-state hydrogen storage offers advantages like safety, high storage density, and low cost, it requires an external heat source to operate the dehydrogenation process. Currently, no commercially available technology can address these issues.

[0051] In order to solve the above-mentioned defects in the prior art, the inventors provide a multi-stage solid-state hydrogen storage system and method for SOFC.

[0052] The present invention is described in further detail below with reference to the accompanying drawings:

[0053] like Figure 1As shown, in the first aspect, an embodiment of the present invention provides a multi-stage solid-state hydrogen storage system for SOFC, including a gaseous hydrogen storage device 1 and an air conveying device 14; the gaseous hydrogen storage device 1 is preferably a gaseous hydrogen storage tank, which is used to convey hydrogen to SOFC7, and the gaseous hydrogen storage device 1 is connected to SOFC7 and a combustion device 8 through a hydrogen reheater 9; an air supply device 13 is connected to the air conveying device 14, and the end of the air supply device 13 is connected to an air reheating device 10 through an air heat recovery device, and the air reheating device 10 is connected to SOFC7, and the air reheating device 10 is preferably an air reheater; a plurality of reactors are installed between the gaseous hydrogen storage device 1 and the hydrogen reheater 9, and the reactors include a TiFe reactor 2, a Mg2Ni reactor 3 and a TiH2 reactor 5, and the TiFe reactor 2, the Mg2Ni reactor 3 and the TiH2 reactor 5 are connected in sequence. The system achieves multi-stage solid-state storage of hydrogen through the TiFe reactor 2, the Mg2Ni reactor 3, and the TiH2 reactor 5. It can effectively store and release hydrogen under different conditions, thereby improving the hydrogen storage capacity and flexibility of the entire system. The gaseous hydrogen storage device 1, serving as the primary storage and delivery unit for hydrogen, can achieve efficient hydrogen storage through high-pressure technology. The hydrogen reheater 9 can preheat the hydrogen before it enters the SOFC 7, increasing its reactivity and thus optimizing the power generation efficiency of the SOFC 7. Finally, by integrating the SOFC 7 with the multi-stage solid-state hydrogen storage device, the system provides the SOFC 7 with safe, high-density, and low-cost hydrogen storage capabilities. The high-temperature waste heat generated during the SOFC 7 power generation process provides a driving heat source for the dehydrogenation of the solid-state hydrogen storage, resolving the difficulties of hydrogen storage and the wide explosion limit range that prevents the SOFC 7 from using hydrogen as a fuel. Furthermore, while solid-state hydrogen storage offers the advantages of safety, high-density hydrogen storage, and low cost, it also addresses the existing technical drawback of requiring an external driving heat source to operate the dehydrogenation process.

[0054] like Figure 1As shown, a MgH2 reactor 4 is connected between the Mg2Ni reactor 3 and the TiH2 reactor 5. Through the MgH2 reactor 4, a more diversified solid-state hydrogen storage method is achieved. MgH2, as an efficient hydrogen storage material, has the advantages of high hydrogen storage density and moderate hydrogen release temperature, which can further improve the system's hydrogen storage capacity and hydrogen release efficiency. In the application process, the TiFe reactor 2 is a hydrogen storage reactor filled with TiFeMn or TiFe-based metal hydrides; the Mg2Ni reactor 3 is a hydrogen storage reactor filled with Mg2Ni-based metal hydrides; the MgH2 reactor 4 is a hydrogen storage reactor filled with Mg-based metal hydrides; and the TiH2 reactor 5 is a hydrogen storage reactor filled with Ti-based metal hydrides. By filling different types of metal hydrides in different types of reactors, the system can be flexibly adjusted under different operating conditions to adapt to different energy needs and hydrogen storage requirements. In order to ensure the safety and reliability of the hydrogen storage process, a pressure control device 6 is connected between the gaseous hydrogen storage device 1 and the hydrogen reheater 9. The pressure control device 6 is used to adjust the hydrogen pressure output by the gaseous hydrogen storage device 1. The pressure control device 6 is preferably a pressure control valve. By setting the pressure control valve, the system can not only accurately adjust the hydrogen pressure output by the gaseous hydrogen storage device 1, but also maintain the stable operation of the system and protect various components from high-pressure shocks. Figure 1 As shown, SOFC 7 has an anode end and a cathode end. The hydrogen reheater 9 is connected to the anode end and can preheat the hydrogen entering the SOFC. The preheated hydrogen has higher reactivity and can more fully react electrochemically with the oxygen provided by the cathode end, thereby improving the power generation efficiency of the SOFC. The air reheater 10 is connected to the cathode end and can preheat the air entering the SOFC7. The preheated air contains more heat energy and can more effectively participate in the electrochemical reaction, further improving the operating efficiency of the SOFC 7. Figure 1 As can be seen in the figure, both the anode and cathode ends of the SOFC 7 are connected to the combustion device 8. When the output power of the SOFC 7 needs to be adjusted, the combustion device 8 can be flexibly started or shut down to provide additional heat or electricity, enhancing the flexibility and reliability of the system and enabling it to adapt to different energy needs and operating conditions. Furthermore, if the SOFC 7 fails or requires maintenance, the combustion device 8 can serve as a backup power or heat source to ensure continued system operation, improving system reliability and stability and reducing downtime caused by failures.

[0055] like Figure 1As shown, the combustion device 8 is also connected to multiple reactors and an air heat recovery device. The heat energy generated by the combustion device 8 can be recovered through the air heat recovery device and used to preheat the air or hydrogen entering the reactor. This heat recovery mechanism significantly improves the thermal energy utilization rate of the entire system, reduces energy waste, and enables the preheated air or hydrogen to more efficiently participate in the chemical reaction in the reactor, thereby improving the performance and efficiency of the reactor, allowing the system to achieve higher production capacity with lower energy consumption. By connecting multiple reactors to the combustion device 8, the system can flexibly adjust the operating status of each reactor according to different energy requirements and working conditions, enhancing the flexibility and adaptability of the system, enabling it to cope with various complex energy scenarios. It is worth noting that in this solution, such as Figure 1 As shown, the air heat recovery device comprises a first air heat recovery unit 11 and a second air heat recovery unit 12. One end of the first air heat recovery unit 11 is connected to the combustion device 8, and the other end is connected to the second air heat recovery unit 12. The second air heat recovery unit 12 is connected to an air supply unit 13, which is preferably a blower. By providing the first air heat recovery unit 11 and the second air heat recovery unit 12, a multi-stage recovery of the heat energy generated by the combustion device 8 is achieved. This multi-stage recovery mechanism can more fully capture and utilize heat energy, improving the heat recovery efficiency of the entire system. Simultaneously, during the multi-stage recovery process, heat energy can be gradually converted into higher-quality heat energy. For example, the preheated air temperature is higher, making it more suitable for subsequent process requirements. The higher air temperature after two stages of heat recovery can more effectively meet the preheated air requirements of the reactor or other process equipment, helping to improve the overall performance and efficiency of the system. Furthermore, due to the higher preheated air temperature, the system can reduce the need for additional heating equipment, thereby reducing energy consumption. In addition, by adjusting the working status of the first air heat recovery device 11 and the second air heat recovery device 12, the system can flexibly adjust the temperature and flow rate of the preheated air according to different process requirements and working conditions. This two-stage heat recovery device operation mode provides a redundancy mechanism. During the operation process, if one of the heat recovery devices fails or requires maintenance, the other heat recovery device can still continue to work, ensuring that the system can continue to provide preheated air.

[0056] The system's hydrogen storage reactor combination may vary depending on the specific application scenario. For example, in the long-term energy storage scenario of a reversible SOFC 7, the electrolysis mode requires heating ambient-temperature water to 700-800°C superheated steam, necessitating the use of medium- and high-temperature reactors such as the MgH2 reactor 4 and TiH2 reactor 5. In fuel cell mode, however, the excess heat in the exhaust gas is present in the water vapor condensation process. To utilize this heat to drive hydrogen release from metal hydrides, a room-temperature reactor such as the TiFe reactor 2 is required. In other words, for the long-term hydrogen storage scenario of a reversible SOFC 7, three hydrogen storage reactors, TiFe reactor 2, MgH2 reactor 4, and TiH2 reactor 5, must be configured, ranging from low to high temperatures. The locations of the waste heat recovery device and other components in the system can be adaptively adjusted or combined based on the specific SOFC 7 design pressure (ambient pressure in the figure) and the application scenario. This invention integrates the SOFC with multi-stage solid-state hydrogen storage, providing safe, high-density, and low-cost hydrogen storage capabilities for the SOFC. Furthermore, the system can adapt to complex operating conditions such as startup and variable operating conditions. Moreover, it is compatible with reversible SOFC operating in electrolysis mode, and has efficient round-trip conversion of electricity-hydrogen-electricity (round-trip efficiency can reach over 70%), which is expected to provide a safe and low-cost hydrogen energy storage solution for long-term energy storage.

[0057] In a second aspect, an embodiment of the present invention provides a method for using a multi-stage solid-state hydrogen storage system for SOFC, wherein the method is performed using the multi-stage solid-state hydrogen storage system as described above. Figure 2 Shown, including:

[0058] S101. Use a gaseous hydrogen storage device to transport hydrogen to the SOFC so that the hydrogen undergoes an electrochemical reaction at the anode end of the SOFC to obtain product water vapor and unreacted high-temperature hydrogen, namely, anode tail gas. For example, since the multiple reactors themselves have no heat source, hydrogen degassing cannot be performed. When the system is started, the gaseous hydrogen storage device is first used to perform hydrogen degassing. The released hydrogen is depressurized by the pressure control device 6 and heated by the hydrogen reheater 9, so that the hydrogen with a temperature range of 800-850°C enters the anode end of the SOFC 7 for electrochemical reaction, and finally the tail gas is discharged from the anode end. The tail gas is a mixed gas of product water vapor and unreacted high-temperature gas, namely, the anode tail gas.

[0059] S102. The anode tail gas heats the multi-stage hydrogen storage reactor and is condensed at the final TiFe reactor. The hydrogen is separated and recovered to continue participating in the anode reaction. Exemplarily, the obtained anode tail gas is used to heat the multi-stage hydrogen storage reactor and is condensed at the final TiFe reactor. The hydrogen is separated and recovered to continue participating in the anode reaction.

[0060] S103. Based on the air conveying device, air is conveyed to the SOFC so that the air undergoes an electrochemical reaction with the anode end of the SOFC while the cathode end of the SOFC discharges the remaining high-temperature air. For example, the air conveying device 14 is used to convey external air into the system pipeline. The air passes through the blower 13, the second air heat recovery device 12, the first air heat recovery device 11 and the air supplementary heat device 10, and the temperature reaches 800-850°C. The air then enters the anode end of the SOFC 7 for an electrochemical reaction, and then the remaining high-temperature air is discharged from the cathode end of the SOFC.

[0061] S104. The remaining high-temperature air is distributed to heat the anode fuel, cathode air, and hydrogen storage reactor. Exemplarily, the remaining high-temperature air is distributed to heat the anode fuel, cathode air, and hydrogen storage reactor.

[0062] S105. When the hydrogen storage reactor or SOFC stack needs further heating, part of the anode tail gas and the remaining high-temperature air are allocated to be burned in the burner to supplement the required heat; illustratively, the remaining high-temperature air is returned for heating, and during the heating process, it is processed in turn through the hydrogen reheater 9 and the air reheater 10 to meet the SOFC 7 inlet temperature requirement (at this time, the high-temperature air still enters the combustion device 8, but the combustion device 8 does not pass the anode tail gas, and no combustion reaction occurs); and, according to the heat supplement requirements of the hydrogen reheater 9, the air reheater 10 and each hydrogen storage reactor, the system can allocate a certain amount of anode tail gas to enter the combustion device 8 for combustion to generate the required heat.

[0063] S106. In the SOFC reverse electrolysis mode, the multi-stage hydrogen storage reactor undergoes an exothermic reaction during hydrogen absorption, heating room-temperature water and providing superheated steam at 700-800°C for the electrolytic hydrogen production process. For example, the primary anode off-gas (approximately 850°C) passes through the TiH2 reactor 5 and is cooled to approximately 670°C, releasing hydrogen at a pressure exceeding 0.1 MPa. The anode off-gas at approximately 670°C enters the MgH2 reactor 4 and is cooled to approximately 300°C, releasing hydrogen at a pressure exceeding 0.1 MPa. The anode off-gas at approximately 300°C enters the Mg2Ni reactor 3 and is cooled to approximately 260°C, releasing hydrogen at a pressure exceeding 0.1 MPa. The anode off-gas at approximately 260°C enters the TiFe reactor 2 and is cooled to approximately 50°C, releasing hydrogen at a pressure exceeding 0.1 MPa. In the TiFe reactor 2, the water vapor in the anode tail gas is condensed and the outlet water is recovered through gas-liquid separation. The separated hydrogen is combined with the mainstream hydrogen after the action of the pressure control device 6 (the pressures of the two airflows are close here), and is collected together with the hydrogen released from each reactor to the main pipe. After being adjusted to the pressure required by the SOFC 7 by the pressure control valve 6, the SOFC 7 can be continuously supplied with hydrogen. At this time, the gaseous hydrogen storage tank 1 is closed and put into standby. In the SOFC reverse electrolysis mode, the multi-stage hydrogen storage reactor undergoes an exothermic reaction during the hydrogen absorption process, heating the room temperature water and providing 700-800°C superheated steam for the electrolytic hydrogen production process.

[0064] Since thermal management is the key to the long life and efficient operation of the SOFC 7 electrolytic stack, the traditional SOFC 7 adopts the method of introducing excess air into the anode to remove the excess heat generated by the SOFC 7 power generation process. In order to adapt to the solid-state hydrogen storage and SOFC 7 coupling system in this solution, and considering dynamic operating conditions such as startup and variable operating conditions, when the SOFC 7 needs to be cooled, the flow rate of the cathode exhaust gas (high-temperature air) entering the air heating device 10 is reduced. When the SOFC 7 needs to be heated or the hydrogen storage reactor is insufficiently supplied with hydrogen, the anode exhaust gas and the cathode exhaust gas are supplemented in the burner to burn and supplement heat, so as to adjust the internal temperature gradient of the SOFC 7 to meet the requirements of stable operation.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit its scope of protection. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that after reading the present invention, those skilled in the art may still make various changes, modifications or equivalent substitutions to the specific implementation methods of the invention, but these changes, modifications or equivalent substitutions are all within the scope of protection of the pending claims of the invention.

Claims

1. A multi-stage solid-state hydrogen storage system for SOFC, characterized in that: include: A gaseous hydrogen storage device (1) and an air conveying device (14); the gaseous hydrogen storage device (1) is connected to the SOFC (7) and the combustion device (8) via a hydrogen reheater (9); an air supply device (13) is connected to the air conveying device (14); an end of the air supply device (13) is connected to the air reheating device (10) via an air heat recovery device, and the air reheating device (10) is connected to the SOFC (7); A plurality of reactors are installed between the gaseous hydrogen storage device (1) and the hydrogen reheater (9), the reactors comprising a TiFe reactor (2), a Mg2Ni reactor (3) and a TiH2 reactor (5), and the TiFe reactor (2), the Mg2Ni reactor (3) and the TiH2 reactor (5) are sequentially connected; A MgH2 reactor (4) is connected between the Mg2Ni reactor (3) and the TiH2 reactor (5); The SOFC (7) has an anode end and a cathode end, the hydrogen reheater (9) is connected to the anode end, and the air reheater (10) is connected to the cathode end; The anode end and the cathode end of the SOFC (7) are both connected to the combustion device (8); The combustion device (8) is also connected to a plurality of reactors and an air heat recovery device; The air heat recovery device comprises a first air heat recovery device (11) and a second air heat recovery device (12), one end of the first air heat recovery device (11) is connected to the combustion device (8), and the other end is connected to the second air heat recovery device (12), and the second air heat recovery device (12) is connected to the air supply device (13).

2. The multi-stage solid-state hydrogen storage system for SOFC according to claim 1, characterized in that: in, The TiFe reactor (2) is a hydrogen storage reactor filled with TiFeMn or TiFe-based metal hydride; The Mg2Ni reactor (3) is a hydrogen storage reactor filled with Mg2Ni-based metal hydride; The MgH2 reactor (4) is a hydrogen storage reactor filled with Mg-based metal hydride; The TiH2 reactor (5) is a hydrogen storage reactor filled with Ti-based metal hydride; A pressure control device (6) is connected between the gaseous hydrogen storage device (1) and the hydrogen reheater (9), and the pressure control device (6) is used to adjust the pressure of hydrogen output by the gaseous hydrogen storage device (1).

3. The multi-stage solid-state hydrogen storage system for SOFC according to claim 2, characterized in that: The pressure control device (6) is a pressure control valve.

4. The multi-stage solid-state hydrogen storage system for SOFC according to claim 1, characterized in that: The air supply device (13) is a blower.

5. The multi-stage solid-state hydrogen storage system for SOFC according to claim 1, characterized in that: The gaseous hydrogen storage device (1) is a gaseous hydrogen storage tank.

6. The multi-stage solid-state hydrogen storage system for SOFC according to claim 1, characterized in that: The air heat replenishment device (10) is an air heat replenishment device.

7. A method for using a multi-stage solid-state hydrogen storage system for SOFC, characterized in that: The method is carried out using the multi-stage solid-state hydrogen storage system according to any one of claims 1 to 6, comprising: Using a gaseous hydrogen storage device to deliver hydrogen to the SOFC, so that the hydrogen undergoes an electrochemical reaction at the anode end of the SOFC to produce a product of water vapor and unreacted high-temperature hydrogen, i.e., anode tail gas; The anode tail gas heats the multi-stage hydrogen storage reactor and is condensed in the final TiFe reactor. The hydrogen is separated and recovered to continue participating in the anode reaction. Using an air delivery device, air is delivered to the SOFC, so that the air undergoes an electrochemical reaction at the cathode end of the SOFC while the cathode end of the SOFC discharges excess high-temperature air; The remaining high-temperature air is distributed to heat the anode fuel, cathode air, and hydrogen storage reactor; When the hydrogen storage reactor or SOFC stack needs further heating, part of the anode tail gas and the remaining high-temperature air are distributed to burn in the burner to supplement the required heat; In the SOFC reverse electrolysis mode, an exothermic reaction occurs during the hydrogen absorption process of the multi-stage hydrogen storage reactor, heating room temperature water and providing 700-800°C superheated steam for the electrolytic hydrogen production process.

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