Shared system components: methane-electric-hydrogen reversible solid oxide fuel cell system

Abstract

This invention discloses a methane-electric-hydrogen reversible solid oxide fuel cell system with shared system components, belonging to the field of hydrogen energy and energy storage. The system mainly consists of a fuel cell stack, electric heater, mixer, splitter, heat exchanger, and combustion chamber. The system can flexibly switch between power generation and electrolysis modes. Components such as the fuel cell stack, feedwater heat exchanger, fuel heat exchanger, and air heat exchanger are used in both fuel cell and electrolysis modes. The use of shared system components greatly improves the utilization rate of system components, reduces system investment costs, and facilitates thermal management. In this system, hydrogen generated in electrolysis mode is directly stored in natural gas pipelines without the need for hydrogen storage equipment, significantly reducing hydrogen storage costs. This technology is expected to solve the large-scale energy storage problem in the utilization of intermittent renewable energy at low cost, and improve the grid's ability to absorb renewable energy.

Description

Technical Field

[0001] This invention belongs to the field of energy storage and hydrogen energy, and specifically relates to a reversible solid oxide fuel cell system using natural gas and methane as fuels; more specifically, it is a reversible operation technology of a solid oxide fuel cell-solid oxide fuel electrolyzer. In fuel cell mode, the system uses a mixture of natural gas and hydrogen as fuel, and in electrolyzer mode, it produces hydrogen. The system operates in both modes using a single set of auxiliary components. This system can both generate electricity from hydrocarbon fuels and electrolyze to produce hydrocarbon fuels, achieving integrated energy storage and power generation equipment. Background Technology

[0002] With the rapid growth of my country's economy and population, energy, as a fundamental driving force, continues to grow. To address the problems caused by fossil fuel supply, the replacement of fossil fuels with renewable energy has become an inevitable trend in the future development of the energy industry. Reversible solid oxide fuel cells (SOCFCs) combine the functions of both SOCFCs and SOCFC electrolyzers, enabling integrated operation in both forward and reverse electrolysis modes. When electricity is needed, it operates in fuel cell mode, converting the chemical energy in the fuel into electrical energy to supply the demand. When there is a power surplus, it operates in electrolyzer mode, converting electrical energy back into fuel for storage and use in power generation. It can achieve efficient utilization of intermittent renewable energy sources and has great application potential.

[0003] In terms of system design and integration, component and system design are the core technologies for achieving high energy efficiency in reversible solid oxide fuel cell systems. The fuel cell stack is the core component of the system, and auxiliary components include equipment such as steam generators, mixers, splitters, and combustion chambers. Electric heaters and heat exchangers are used to meet the heat requirements of system components. The common use of auxiliary components significantly improves the utilization rate of equipment and reduces costs.

[0004] my country has a well-developed natural gas pipeline network. Connecting the fuel cell system to the natural gas pipeline allows the hydrogen produced by the fuel cell in electrolysis mode to be stored in the natural gas pipeline and used during power generation, thereby saving hydrogen storage equipment and reducing system costs.

[0005] Compared to hydrogen-fueled fuel cell systems, methane-fueled fuel cell systems require significantly less air-side heat exchange, effectively reducing the workload of the air-side heat exchanger.

[0006] The invention patent CN 113851617 A, published on December 28, 2021, relates to a solid oxide fuel cell system for reforming natural gas. Liquefied natural gas is vaporized and reformed in a reformer before entering the fuel cell anode. Air is heated by an air heater and then sent to the cell cathode. The exhaust gas is used to separate and utilize carbon dioxide after combustion, thus completing the extraction and utilization of carbon dioxide. However, in this system, the natural gas reforming process is overly simplified, and no practical operating method is provided for utilizing the thermal energy of the exhaust gas; it fails to use this energy to heat the air and provide heat for fuel reforming.

[0007] Utility model patent CN 208898500 U, published on May 24, 2018, relates to a methane reforming system utilizing high-temperature flue gas from a solid oxide fuel cell. After the reformed fuel enters the fuel cell stack, the unreacted exhaust gas is directly fed into the exhaust gas combustion unit. The high-temperature exhaust gas produced after combustion is sequentially fed into the methane reforming unit, the methane supply unit, and the reforming medium supply unit to heat the feedstock and provide heat for the reforming reaction. Because there is no gas diversion device capable of withstanding temperatures above 800°C, the flue gas diversion device described in this patent may have certain limitations in practical operation.

[0008] The invention patent CN 106784960 A, published on May 31, 2017, relates to an integrated reversible fuel cell system, which includes a hydrogen circulation module, an oxygen circulation module, and a water circulation module. It fully utilizes the hydrogen and oxygen produced in electrolysis mode. The water circulation system design saves water, but the system does not consider heat demand and utilization. Furthermore, due to the system's reversible function, a large number of system components are used, increasing the system's investment cost.

[0009] US Patent 7,150,927 B2, published on December 19, 2006, discloses a reversible solid oxide fuel cell system. The fuel cell anode outlet is connected to a heat exchanger. In power generation mode, the high-temperature exhaust gas from the anode enters a gas-liquid separator after heat exchange, where hydrogen is separated, pressurized, and then sent back to the fuel cell anode. In electrolysis mode, the hydrogen produced at the fuel cell anode undergoes heat exchange and gas-liquid separation before being stored in a hydrogen cylinder for use in power generation mode. This system requires a hydrogen cylinder for hydrogen storage, and in power generation mode, when the hydrogen is depleted, power generation can no longer continue.

[0010] Furthermore, publication number CN113745575A discloses a method for measuring a reversible solid oxide fuel cell system, including a gas path control system, a three-electrode measurement system, a voltage and current measurement system, and a gas chromatograph. The three-electrode measurement system includes a fuel cell stack and a box furnace, with the fuel cell stack installed within the box furnace. The box furnace has a fuel electrode and an air electrode connected to the fuel cell stack. The gas path control system includes a gas cylinder, an air compressor, a steam generator, and a gas flow meter. The gas paths of the gas cylinder and the steam generator are both connected to one end of the fuel electrode, and the air compressor is connected to one end of the air electrode. The fuel cell gas outlet is connected to an exhaust system and a gas chromatograph. The gas flow meter is installed on the gas path of the gas cylinder. Both the fuel electrode and the air electrode are connected to the voltage and current measurement system via circuitry. The gas flow meter, gas chromatograph, controllable voltage and current power supply, and electronic load are all electrically connected to a computer. However, this prior art also cannot achieve a methane-electricity-hydrogen reversible solid oxide fuel cell device using shared system components.

[0011] Taking into account the above-mentioned technologies and problems, this invention proposes a methane-electricity-hydrogen reversible solid oxide fuel cell system with shared system components. In this system, most auxiliary components are shared, improving the utilization efficiency of system components. The use of shared thermal system components such as the feedwater heat exchanger, heat exchange steam generator, fuel heat exchanger, fuel-side heat exchanger, and air-side heat exchanger fully utilizes the thermal energy in the stack exhaust gas. In power generation mode, the fuel-side exhaust gas first passes through the fuel-side heat exchanger, reducing its temperature to a suitable level, thus providing an application environment for the splitter. Hydrogen produced in electrolysis mode is cooled, separated from water, and stored in a natural gas pipeline, eliminating the need for dedicated hydrogen storage equipment. Summary of the Invention

[0012] To address the shortcomings of existing technologies, this invention proposes a methane-electric-hydrogen reversible solid oxide fuel cell system with shared system components, the technical solution of which is as follows:

[0013] A methane-electricity-hydrogen reversible solid oxide fuel cell system with shared components is characterized by its ability to switch between power generation and electrolysis modes. In power generation mode, the system supplies electricity to the outside, while in electrolysis mode, it produces and stores hydrogen. The system includes shared system components that can be used in both power generation and electrolysis modes. These shared system components perform the following functions: heating feedwater, fuel, and air using the high-temperature exhaust gas from the fuel cell stack; providing fuel and air to the fuel cell stack; and ensuring the system's thermal and fuel management. The shared system components include: a fuel cell stack, a feedwater heat exchanger, a fuel-side heat exchanger, an air-side heat exchanger, a mixer, a distributor, a burner, and a natural gas pipeline.

[0014] In the system power generation mode, the system components are connected as follows: the feedwater heat exchanger is connected in series with the heat exchange steam generator, fuel heat exchanger, fuel reformer, fuel-side heat exchanger of the fuel stack, and the fuel stack; the mixer is connected in series with the fuel heat exchanger, fuel reformer, fuel-side heat exchanger of the fuel stack, distributor, and natural gas pipeline to form a loop; the fuel-side heat exchanger of the fuel stack is connected in series with the distributor and burner; the air-side heat exchanger of the fuel stack is connected in series with the fuel stack; and the burner is connected to the air-side heat exchanger of the fuel stack, fuel heat exchanger, heat exchange steam generator, and feedwater heat exchanger respectively.

[0015] The upgrading functional component in the power generation mode is characterized by comprising a fuel heat exchanger and a fuel reformer. The fuel heat exchanger utilizes high-temperature exhaust gas from the burner to heat the supplied fuel and feedwater, providing the necessary heat for fuel reforming. The fuel reformer reforms hydrogen-doped methane into hydrogen, which is then fed into the fuel-side heat exchanger of the fuel stack and subsequently reacts at the anode. During fuel reforming, the conversion of alkane compounds into hydrogen absorbs a significant amount of heat, reducing the amount of air required to cool the fuel stack and lowering the workload of the air-side heat exchanger, thus benefiting system thermal management. The upgrading functional component upgrades the supplied fuel, converting alkane fuel into hydrogen before it is fed into the system fuel stack, thus avoiding carbon buildup reactions within the fuel stack.

[0016] In the system electrolysis mode, the system components are connected as follows: the feedwater heat exchanger is connected in series with the electric steam generator, the mixer, and the fuel-side heat exchanger of the fuel cell stack; the fuel-side heat exchanger of the fuel cell stack is connected in series with the distributor, the cooler, the steam-water separator, and the natural gas pipeline to form a loop; the air-side heat exchanger of the fuel cell stack is connected in series with the fuel-side electric heater and the fuel cell stack to form a loop; the air-side heat exchanger of the fuel cell stack is connected in series with the air-side electric heater, the fuel cell stack, and the burner to form a loop; and the air-side heat exchanger of the fuel cell stack is connected in series with the feedwater heat exchanger.

[0017] The hydrogen storage components in electrolysis mode include a distributor, cooler, vapor-water separator, and natural gas pipeline. The distributor provides the fluid flow path; the cooler cools the mixed hydrogen and water vapor stream and liquefies the water vapor; the vapor-water separator separates the hydrogen from the condensate; and the natural gas pipeline stores the hydrogen separated by the vapor-water separator. The hydrogen storage components process the hydrogen produced by the fuel cell stack and store it in the natural gas pipeline, eliminating the need for additional hydrogen storage equipment and significantly reducing system component costs.

[0018] The present invention also discloses a control method for a methane-electric-hydrogen reversible solid oxide fuel cell system with shared system components, including the aforementioned methane-electric-hydrogen reversible solid oxide fuel cell system with shared system components.

[0019] The power generation process is as follows: Industrial water is heated by a feedwater heat exchanger and then steamed in a heat exchange steam generator. This steam, along with hydrogen and natural gas from the natural gas pipeline, is fed into a mixer. The mixed fuel is heated in a fuel heat exchanger and then fed into a fuel reformer. After reforming in the reformer, it is heated in the fuel-side heat exchanger of the fuel cell stack and then enters the fuel electrode of the fuel cell stack. Air is heated by the air-side heat exchanger of the fuel cell stack and then enters the air electrode of the fuel cell stack. Inside the fuel cell stack, hydrogen reacts with oxygen in the air to produce water. The fuel electrode of the fuel cell stack discharges unreacted hydrogen and water vapor, which is then heated by the fuel-side heat exchanger to produce hydrogen from the fuel reformer. This hydrogen then passes through a splitter into the burner, where it is burned with oxygen-deficient air discharged from the air electrode of the fuel cell stack. The high-temperature exhaust gas from the burner is heated by the air-side heat exchanger to supply air, then by the feedwater heater to heat feedwater, then by the fuel heat exchanger to heat fuel, and finally by the heat exchange steam generator to produce steam.

[0020] The electrolysis mode workflow is as follows: Exhaust gas from the fuel cell stack air-side heat exchanger is heated to water by the feedwater heat exchanger, and then heated to generate steam by the electric steam generator. This steam then passes through a mixer, fuel-side heat exchanger, and fuel-side electric heater for further heating before entering the fuel electrode of the fuel cell stack. Air is heated by the fuel cell stack air-side heat exchanger and then heated by the air-side electric heater before entering the fuel electrode of the fuel cell stack. An electrolysis reaction of water occurs inside the fuel cell stack. The mixture of hydrogen and steam discharged from the fuel electrode is heated by the fuel-side heat exchanger to generate steam from the mixer. Based on the system's heat demand, a portion of the hydrogen is diverted by a splitter into the combustion chamber, where it burns with the air discharged from the fuel cell stack air electrode. The remaining portion is cooled by the splitter and then enters a steam-water separator for separation before being sent to a natural gas pipeline for storage. The high-temperature exhaust gas from the combustion chamber is heated by the fuel cell stack air-side heat exchanger to supply air, and the exhaust gas from the fuel cell stack air-side heat exchanger is heated by the feedwater heat exchanger to supply water.

[0021] The present invention also discloses a methane-electric-hydrogen reversible solid oxide fuel cell system with shared system components applied in energy storage production equipment. Beneficial effects

[0022] (1) In both operating modes of this system, shared system components will be put into use. In addition to shared cooling system components, more importantly, high-temperature heat exchangers are shared, including: feedwater heat exchanger, fuel-side heat exchanger of the fuel cell stack, and air-side heat exchanger of the fuel cell stack. The use of shared system components improves the utilization rate of system components, saves system investment, and provides convenience for system thermal management.

[0023] (2) It can realize flexible switching between fuel cell / electrolysis mode. When the power supply is sufficient, the power can be converted into hydrogen and stored in the natural gas pipeline. When there is a demand for power, the fuel can be fed into the stack and converted into power. The system can switch modes in response to changes in external load to meet the actual needs of power consumption and energy storage, which can greatly improve the annual utilization rate of the system.

[0024] (3) Effectively solves the problem of large difference in heat exchange load between air-side heat exchanger in fuel cell mode and electrolysis mode in hydrogen-electricity-hydrogen reversible system, and improves the utilization rate of common system components; For fuel cell systems using pure hydrogen as fuel, stack cooling can only rely on inlet air, and the large amount of air required results in a large air-side heat exchange load, which far exceeds the heat exchange capacity of the same heat exchanger in electrolysis mode; For fuel cell systems using natural gas or hydrogen-blended natural gas, most of the natural gas reforming process can occur inside the stack. Taking a 5kW stack as an example, for a solid oxide fuel cell system using pure hydrogen as fuel, the pre-side heat exchange capacity of the air side is 15.3kW in SOFC mode and 5kW in SOEC mode. For a solid oxide fuel cell system using methane as fuel, the pre-side heat exchange capacity of the air side is 9.45kW in SOFC mode and 5kW in SOEC mode. The heat-absorbing reforming process can effectively assist in the thermal management of the fuel cell stack, thereby reducing the amount of air used to remove the heat released by the electrochemical reactions within the stack. This significantly reduces the heat exchange load on the air-side heat exchanger, making the air-side heat exchange load more matched between the two modes. It also maximizes the sharing of heat exchangers, which helps reduce the overall system investment cost.

[0025] (4) The hydrogen produced in the electrolysis mode is cooled, purified and compressed to the pressure of the natural gas pipeline, and can be directly introduced into the natural gas pipeline without the need for additional high-pressure hydrogen compression and storage equipment, which effectively reduces the cost of hydrogen storage.

[0026] (5) The key difference between the system described in this invention and the conventional RSOC system lies in the connection of a heat exchanger to the fuel-side outlet of the fuel stack. The high-temperature exhaust gas from the fuel-side outlet is heated by the heat exchanger and supplied to the fuel for cooling before being introduced into the splitter and other cooling components. This ensures that the flue gas temperature remains within a suitable temperature range to meet the operating temperature requirements of the splitter and other cooling components. This provides a basis for the splitter and other cooling components to be used in both battery mode and electrolysis mode. In conventional SOEC systems, the hydrogen produced is directly stored after cooling and gas-liquid separation. In the system described in this invention, a portion of the hydrogen can be allocated to the burner for combustion after system thermal balance calculations to assist in system thermal management.

[0027] (6) The system described in this invention can use a steam generator that integrates electricity and heat exchange for both fuel cell mode and electrolysis mode, which can further improve the utilization rate of system accessories and reduce system investment. Attached Figure Description

[0028] Figure 1 A schematic diagram of a methane-electric-hydrogen reversible solid oxide fuel cell system with shared system components.

[0029] Figure 2 A schematic diagram of the power generation mode of a methane-electric-hydrogen reversible solid oxide fuel cell system with shared system components.

[0030] Figure 3 A schematic diagram of the electrolysis mode of a methane-electric-hydrogen reversible solid oxide fuel cell system with shared system components.

[0031] In the diagram: 1-Feedwater heat exchanger, 2-Electric steam generator, 3-Mixer, 4-Fuel reformer, 5-Fuel stack fuel-side heat exchanger, 6-Fuel-side electric heater, 7-Fuel cell stack, 8-Air-side electric heater, 9-Burner, 10-Fuel stack air-side heat exchanger, 11-Diverter, 12-Cooler, 13-Steam-water separator, 14-Natural gas pipeline, 15-Heat exchange type steam generator, 16-Fuel heat exchanger. Detailed Implementation

[0032] This invention proposes a methane-electric-hydrogen reversible solid oxide fuel cell system with shared system components, which will be described below with reference to the accompanying drawings.

[0033] like Figure 1-3 The reversible solid oxide fuel cell system with shared system auxiliary components shown includes the system's power generation mode and electrolysis mode. In the system's power generation mode, the system components are connected as follows: the feedwater heat exchanger 1 is connected in series with the heat exchange steam generator 15, the fuel heat exchanger 16, the fuel reformer 4, the fuel-side heat exchanger 5, and the fuel stack 7; the mixer 3 is connected in series with the fuel heat exchanger 16, the fuel reformer 4, the fuel-side heat exchanger 5, the splitter 11, and the natural gas pipeline 14 to form a loop; the fuel-side heat exchanger 5 is connected in series with the splitter 11 and the burner 9; the air-side heat exchanger 10 is connected in series with the fuel stack 7; and the burner 9 is connected to the air-side heat exchanger 10, the fuel heat exchanger 16, the heat exchange steam generator 15, and the feedwater heat exchanger 1, respectively.

[0034] This invention utilizes the working process of a reversible solid oxide fuel cell system power generation mode with shared system auxiliary components. The working process is as follows: Industrial water is heated by a feedwater heat exchanger 1 and then converted into steam in a heat exchange steam generator 15. This steam, along with hydrogen and natural gas from a natural gas pipeline 14, is fed into a mixer 3. The mixed fuel is heated in a fuel heat exchanger 16 and then fed into a fuel reformer 4. After reforming in the fuel reformer 4, the fuel is further heated by the fuel-side heat exchanger 5 and then enters the fuel electrode of the fuel cell stack 7. Air is heated by the air-side heat exchanger 10 and then enters the fuel electrode of the fuel cell stack 7. The hydrogen gas enters the air electrode of the fuel cell stack 7; inside the fuel cell stack 7, hydrogen reacts with oxygen in the air to produce water. The fuel electrode of the fuel cell stack 7 discharges unreacted hydrogen and water vapor, which is heated by the fuel side heat exchanger 5. The hydrogen from the fuel reformer 4 is then heated by the fuel side heat exchanger 5 and then enters the combustor 9 through the splitter 11, where it is burned with the oxygen-deficient air discharged from the air electrode of the fuel cell stack 7. The high-temperature exhaust gas from the combustor 9 is heated by the fuel cell stack air side heat exchanger 10 to supply air, heated by the feed water heater 1, heated by the fuel heat exchanger 16 to heat fuel, and then generated as steam by the heat exchange steam generator 15.

[0035] The upgrading functional component in the power generation mode is characterized by comprising a fuel heat exchanger 16 and a fuel reformer 4. The fuel heat exchanger 16 utilizes the high-temperature exhaust gas from the burner 9 to heat the supplied fuel and feedwater, providing the necessary heat for fuel reforming. The fuel reformer 4 reforms hydrogen-doped methane into hydrogen, which is then fed into the fuel-side heat exchanger 5 and subsequently reacts at the anode of the fuel stack. During fuel reforming, the conversion of alkane compounds into hydrogen absorbs a large amount of heat, reducing the amount of air required to cool the fuel stack and lowering the workload of the air-side heat exchanger, thus benefiting system thermal management. The upgrading functional component upgrades the supplied fuel, converting alkane fuel into hydrogen before it is fed into the system fuel stack, thus avoiding carbon buildup within the fuel stack.

[0036] In the system power generation mode and the system electrolysis mode, the system components are connected as follows: the feedwater heat exchanger 1 is connected in series with the electric steam generator 2, the mixer 3, and the fuel-side heat exchanger 5 of the electric stack; the fuel-side heat exchanger 5 of the electric stack is connected in series with the distributor 11, the cooler steam-water separator 13, and the natural gas pipeline 14 to form a loop; the air-side heat exchanger 5 of the electric stack is connected in series with the fuel-side electric heater 6 and the electric stack 7 to form a loop; the air-side heat exchanger 10 of the electric stack is connected in series with the air-side electric heater 8, the electric stack 7, and the burner 10 to form a loop; and the air-side heat exchanger 10 of the electric stack is connected in series with the feedwater heat exchanger 1.

[0037] This invention utilizes the electrolysis mode workflow of a reversible solid oxide fuel cell system with shared system auxiliary components. The electrolysis mode workflow is as follows: Exhaust gas from the stack air-side heat exchanger 10 is heated to water by the feedwater heat exchanger 1, and then heated to generate steam by the electric steam generator 2. The steam then passes through the mixer 3, the stack fuel-side heat exchanger 5, and the fuel-side electric heater 6 for further heating before entering the fuel electrode of the fuel cell stack 7. Air is heated by the stack air-side heat exchanger 10, and then heated by the air-side electric heater 8 before entering the air electrode of the fuel cell stack. An electrolysis reaction of water occurs inside the fuel cell stack 7. The mixture of hydrogen and water vapor discharged from the fuel electrode is heated by the fuel-side heat exchanger 5 of the fuel cell stack to heat the water vapor from the mixer. Then, based on the system's heat demand, a portion of the hydrogen is diverted by the splitter 11 into the combustion chamber 9, where it is burned with the air discharged from the air electrode of the fuel cell stack 7. The other portion is cooled by the cooler 12 through the splitter 11 and then enters the steam-water separator 13 for steam-water separation before being sent to the natural gas pipeline 14 for storage. The high-temperature exhaust gas discharged from the combustion chamber 9 enters the air-side heat exchanger 10 of the fuel cell stack to heat and supply air. The exhaust gas discharged from the air-side heat exchanger 10 of the fuel cell stack is heated by the feedwater heat exchanger 1 to supply water.

[0038] The hydrogen storage components in electrolysis mode include a distributor 11, a cooler 12, a vapor-water separator 13, and a natural gas pipeline 14. The distributor 11 provides a fluid passage; the cooler 12 cools the mixed hydrogen and water vapor stream, liquefying the water vapor; the vapor-water separator 13 separates the hydrogen and condensate mixture; and the natural gas pipeline 14 stores the hydrogen separated by the vapor-water separator 13. No additional high-pressure hydrogen compression and storage equipment is required, effectively reducing hydrogen storage costs.

[0039] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A methane-electric-hydrogen reversible solid oxide fuel cell system with shared system components, characterized in that; The system can switch between power generation and electrolysis modes. In power generation mode, the system transmits electricity to the outside, and in electrolysis mode, it produces and stores hydrogen. The system components can be used in both power generation and electrolysis modes. The shared system components are divided into shared cold system components and shared hot system components. The shared cold system components include: mixers, distributors, and natural gas pipelines, which provide fluid channels and storage containers for fuel and air. The shared hot system components include: fuel cell stack, feedwater heat exchanger, fuel-side heat exchanger, air-side heat exchanger, and burner. Their functions are as follows: using the high-temperature exhaust gas from the fuel cell stack to heat the feedwater, fuel, and air; providing fuel and air for the fuel cell stack; and ensuring the system's thermal and fuel management. In the system power generation mode: the feedwater heat exchanger is connected in series with the heat exchange steam generator, fuel heat exchanger, fuel reformer, fuel-side heat exchanger of the fuel stack, and fuel cell stack; the mixer is connected in series with the fuel heat exchanger, fuel reformer, fuel-side heat exchanger of the fuel stack, splitter, and natural gas pipeline to form a loop; the fuel-side heat exchanger of the fuel stack is connected in series with the splitter and burner; the air-side heat exchanger of the fuel stack is connected in series with the fuel cell stack; and the burner is connected to the air-side heat exchanger of the fuel stack, fuel heat exchanger, heat exchange steam generator, and feedwater heat exchanger respectively. The power generation process is as follows: Industrial water is heated by a feedwater heat exchanger and then steamed in a heat exchange steam generator. This steam, along with hydrogen and natural gas from the natural gas pipeline, is fed into a mixer. The mixed fuel is heated in a fuel heat exchanger and then fed into a fuel reformer. After reforming in the fuel reformer, it is heated in the fuel-side heat exchanger of the fuel cell stack and then enters the fuel electrode of the fuel cell stack. Air is heated by the air-side heat exchanger of the fuel cell stack and then enters the air electrode of the fuel cell stack. Inside the fuel cell stack, hydrogen reacts with oxygen in the air to produce water. The fuel electrode of the fuel cell stack discharges unreacted hydrogen and water vapor, which is then heated by the fuel-side heat exchanger to produce hydrogen from the fuel reformer. This hydrogen then passes through a splitter into the burner, where it is burned with oxygen-deficient air discharged from the air electrode of the fuel cell stack. The high-temperature exhaust gas from the burner is heated by the air-side heat exchanger to supply air, then by a feedwater heater to heat feedwater, then by a fuel heat exchanger to heat fuel, and finally by a heat exchange steam generator to produce steam. In the system electrolysis mode: the feedwater heat exchanger is connected in series with the electric steam generator, the mixer, and the fuel-side heat exchanger of the fuel cell stack; the fuel-side heat exchanger of the fuel cell stack is connected in series with the distributor, the cooler, the steam-water separator, and the natural gas pipeline to form a loop; the fuel-side heat exchanger of the fuel cell stack is connected in series with the fuel-side electric heater and the fuel cell stack to form a loop; the air-side heat exchanger of the fuel cell stack is connected in series with the air-side electric heater, the fuel cell stack, and the burner to form a loop; and the air-side heat exchanger of the fuel cell stack is connected in series with the feedwater heat exchanger. The electrolysis mode workflow is as follows: Exhaust gas from the fuel cell stack air-side heat exchanger is heated to water by the feedwater heat exchanger, and then heated to generate steam by the electric steam generator. This steam then passes through a mixer, fuel-side heat exchanger, and fuel-side electric heater for further heating before entering the fuel electrode of the fuel cell stack. Air is heated by the fuel cell stack air-side heat exchanger and then heated by the air-side electric heater before entering the fuel electrode of the fuel cell stack. An electrolysis reaction of water occurs inside the fuel cell stack. The mixture of hydrogen and steam discharged from the fuel electrode is heated by the fuel-side heat exchanger to generate steam from the mixer. Based on the system's heat demand, a portion of the hydrogen is diverted by a splitter to the burner, where it is burned with the air discharged from the fuel cell stack air electrode. The remaining portion is cooled by the splitter and then enters a steam-water separator for separation before being sent to a natural gas pipeline for storage. The high-temperature exhaust gas from the burner is heated by the fuel cell stack air-side heat exchanger to supply air, and the exhaust gas from the fuel cell stack air-side heat exchanger is heated by the feedwater heat exchanger to supply water.

2. A methane-electric-hydrogen reversible solid oxide fuel cell system with shared system components according to claim 1, characterized in that: The power generation mode includes a quality improvement function component, which comprises a fuel heat exchanger and a fuel reformer. The fuel heat exchanger uses the high-temperature exhaust gas provided by the burner to heat the fuel and feedwater, providing the heat required for fuel reforming. The fuel reformer reforms hydrogen-doped methane into hydrogen, which is then sent to the fuel-side heat exchanger of the fuel stack and enters the anode of the fuel stack for reaction.

3. The methane-electric-hydrogen reversible solid oxide fuel cell system with shared system components according to claim 1, characterized in that: The hydrogen storage component in electrolysis mode includes: a distributor, a cooler, a vapor-water separator, and a natural gas pipeline; wherein the distributor provides a fluid passage; the cooler is used to cool the mixed gas flow of hydrogen and water vapor and liquefy the water vapor; the vapor-water separator is used to separate the mixture of hydrogen and condensate; and the natural gas pipeline is used to store the hydrogen separated by the vapor-water separator.

4. The methane-electric-hydrogen reversible solid oxide fuel cell system according to claim 1, characterized in that, In power generation mode, the exhaust gas from the fuel cell stack is fed into a feedwater heat exchanger, a heat exchange steam generator, a fuel heat exchanger, a fuel-side heat exchanger, and an air-side heat exchanger. In electrolysis mode, the exhaust gas from the fuel cell stack is fed into a feedwater heat exchanger, a fuel-side heat exchanger, and an air-side heat exchanger.

5. An energy storage and production device, characterized in that: The device includes a methane-electric-hydrogen reversible solid oxide fuel cell system with shared system components as described in claim 1.

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