A high-efficiency power generation process and system coupling hydrogen fuel cells and thermochemical energy storage

Abstract

The application belongs to the technical field of energy saving and environmental protection, and relates to a high-efficiency power generation process and system coupling a hydrogen fuel cell and a thermochemical energy storage. The power generation process comprises an energy storage process and a power generation process. The power generation process is as follows: hydrogen and oxygen generated in an electrolysis process are introduced into a hydrogen fuel cell to generate electric energy and high-temperature water vapor through an electrochemical reaction, liquid water generated in a pyrolysis process is gasified into reaction steam by using the high-temperature water vapor, the reaction steam is prepared into mixed gas, the partial pressure of the reaction steam is adjusted, and then the mixed gas is reacted with a calcium carbide slag dehydration product to generate heat energy, and the generated heat energy is used to generate power by a steam turbine generator. The application can not only solve the problem of utilization of high-temperature steam discharge of a medium-high temperature hydrogen fuel cell, but also solve the problems of low energy consumption of gaseous reactants of a calcium carbide slag thermochemical energy storage system and limitation of the storage density of calcium carbide slag by the proportion of effective heat storage materials.

Description

Technical Field

[0001] This invention belongs to the field of energy conservation and environmental protection technology, and relates to a high-efficiency power generation process and system that couples hydrogen fuel cells and thermochemical energy storage. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] The proportion of renewable energy generation, such as solar and wind power, in the power system is gradually increasing. However, the intermittent and fluctuating nature of renewable energy leads to a mismatch between energy supply and demand in time and space. Therefore, energy storage devices are needed to achieve energy supply-demand matching and ensure the stable operation of the power system. Utilizing off-peak green electricity for water electrolysis to produce hydrogen and oxygen is a promising energy storage technology, which converts electrical energy into the chemical energy of substances for storage. Hydrogen fuel cells are widely used due to their high power generation efficiency and low pollution, and can be used as regional power plants. When electricity is needed, the stored hydrogen and oxygen are supplied to the anode and cathode of the fuel cell, respectively, and the chemical energy of hydrogen and oxygen is directly converted into electrical energy through an electrochemical reaction.

[0004] According to the inventors' research, medium- and high-temperature hydrogen fuel cells (such as solid oxide hydrogen fuel cells and molten carbonate hydrogen fuel cells) suitable for district power supply operate at high temperatures. The operating temperature range of solid oxide hydrogen fuel cells is generally 800–1000°C, while that of molten carbonate hydrogen fuel cells is generally 600–700°C. This higher operating temperature results in higher temperatures in the exhaust gas (i.e., water vapor) (600–800°C). Since high-temperature water vapor contains a large amount of sensible and latent heat, failure to fully utilize this high-temperature water vapor will reduce the energy efficiency of the hydrogen fuel cell. Summary of the Invention

[0005] To effectively address the problem of utilizing high-temperature steam emissions from medium- and high-temperature hydrogen fuel cells, the present invention aims to provide a high-efficiency power generation process and system that couples hydrogen fuel cells and thermochemical energy storage, which can effectively improve the utilization of high-temperature steam emissions from high-temperature hydrogen fuel cells.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] On the one hand, there is a high-efficiency power generation process that couples hydrogen fuel cells and thermochemical energy storage, including an energy storage process and a power generation process;

[0008] The energy storage process includes an electrolysis process and a pyrolysis process. The electrolysis process involves using a portion of the electrical energy to electrolyze water to produce hydrogen and oxygen. The pyrolysis process involves using another portion of the electrical energy to heat the calcium carbide slag, causing the calcium hydroxide in it to absorb heat and dehydrate to form calcium carbide slag dehydration products and liquid water.

[0009] The power generation process is as follows: hydrogen and oxygen generated during the electrolysis process are fed into a hydrogen fuel cell to undergo an electrochemical reaction to generate electricity, and high-temperature water vapor at 600-800°C is discharged. The high-temperature water vapor is used to vaporize the liquid water generated during the pyrolysis process to form reaction steam. A gas without carbon dioxide is added to the reaction steam to form a mixed gas. The partial pressure of the reaction steam in the mixed gas is adjusted by the gas without carbon dioxide. The mixed gas with adjusted steam partial pressure undergoes an exothermic reaction with the dehydration product of carbide slag to generate heat energy. The generated heat energy is used to generate electricity using a steam turbine generator.

[0010] Thermochemical energy storage based on the reversible chemical reaction principle of calcium hydroxide dehydration and calcium oxide hydration can also be used for large-scale energy storage. When energy storage is needed, calcium hydroxide is electrically heated to dehydrate it, producing calcium oxide and water vapor, thus converting electrical energy into heat energy, which is ultimately stored in the material structure as chemical energy. When energy is needed, calcium oxide and water vapor are mixed again, and the calcium oxide reacts with the water vapor to produce calcium hydroxide. This reaction is exothermic, converting the stored chemical energy into heat energy, which is then used to generate electricity through heat-work conversion. The key factor affecting the energy efficiency of the calcium hydroxide thermochemical energy storage system is that the stored liquid water (below 100°C) needs to be heated to turn into water vapor during the exothermic process. Due to the large latent heat of phase change of water, this process requires a large amount of heat. Although the reaction between calcium oxide and water vapor in the calcium carbide slag dehydration product releases more heat, the unavoidable heat loss during the water vapor production process will greatly reduce the energy efficiency of this thermochemical energy storage system. This invention uses high-temperature steam generated by a high-temperature hydrogen fuel cell to heat liquid water during energy use, turning it into steam. Then, the steam reacts exothermically with the dehydration products of calcium carbide slag, which are mainly composed of calcium oxide, to generate heat energy. This not only effectively improves the utilization of high-temperature steam emissions from the high-temperature hydrogen fuel cell, but also solves the problem of low-energy consumption in obtaining steam during the exothermic reaction of steam with the dehydration products of calcium carbide slag, which are mainly composed of calcium oxide, to generate heat energy.

[0011] Meanwhile, since the equilibrium temperature of the calcium oxide hydration reaction is related to the vapor partial pressure of the reaction atmosphere, the equilibrium temperature corresponding to a pure vapor atmosphere under one atmosphere of pressure is 520℃. Therefore, in order to adjust the exothermic temperature, it is necessary to introduce a gas to control the vapor partial pressure and thus control the equilibrium temperature, so as to better realize the conversion of chemical energy into thermal energy.

[0012] The main component of calcium carbide slag is calcium hydroxide (up to 80% by mass), and the minor component is calcium carbonate (up to 10% by mass). Calcium carbide slag can replace high-purity calcium hydroxide. However, the decomposition temperature of calcium carbonate is much higher than that of calcium hydroxide, so intuitively, the heat storage density of calcium carbide slag is lower than that of high-purity calcium hydroxide. However, this invention unexpectedly discovered that calcium carbide slag exhibits a self-compensating effect when undergoing heat storage cycling in a carbon dioxide-free gas environment. This not only improves the energy efficiency of each subsystem but also achieves high energy efficiency in the coupled system and enhances the performance (purification) of the calcium carbide slag heat storage material. Specifically, after undergoing cyclic energy storage and release, the calcium hydroxide content in the calcium carbide slag can increase from 80% to 87%, while the calcium carbonate content decreases from 10% to 3%. The self-compensating effect of the aforementioned calcium carbide slag occurs under the condition that the atmosphere is free of carbon dioxide. Therefore, this invention uses a carbon dioxide-free gas mixed with the reaction steam and adjusts the steam partial pressure.

[0013] On the other hand, a high-efficiency power generation system coupling hydrogen fuel cells and thermochemical energy storage, used to realize the above-mentioned high-efficiency power generation process coupling hydrogen fuel cells and thermochemical energy storage, includes:

[0014] The water electrolysis hydrogen production device is used to realize the electrolysis process of the energy storage process, and stores the generated hydrogen and oxygen in hydrogen storage tanks and oxygen storage tanks respectively.

[0015] Hydrogen fuel cell power generation device, which uses hydrogen in hydrogen storage tank and oxygen in oxygen storage tank to realize the electrochemical reaction of the power generation process to generate electricity and high temperature water vapor;

[0016] Thermochemical energy storage and power generation device is used to realize the pyrolysis process of energy storage and the process of generating heat energy by using high-temperature water vapor, dehydrated carbide slag products and liquid water generated by hydrogen fuel cell power generation device to produce heat energy, and using the generated heat energy to generate electricity by steam turbine generator.

[0017] The beneficial effects of this invention are as follows:

[0018] This invention utilizes the high-temperature steam generated during the energy release process of a high-temperature hydrogen fuel cell as a reactant in the exothermic process of a calcium carbide slag thermochemical energy storage system. This coupling process effectively solves the problems of high-temperature steam emission utilization in medium- and high-temperature hydrogen fuel cells and steam generation during the energy release process of calcium carbide slag thermochemical energy storage, achieving efficient utilization of both material and energy flows. Furthermore, after multiple heat storage cycles, the minor component calcium carbonate in the calcium carbide slag can be converted into effective heat storage material calcium hydroxide, increasing the purity of calcium hydroxide in the calcium carbide slag, thereby increasing the energy storage density of the calcium carbide slag, delaying the degradation of its heat storage performance, and enabling it to achieve heat storage for more cycles. Currently, the overall conversion efficiency of various fuel cells in actual operation is mostly in the range of 45%-60%, while this invention, after fully utilizing its emitted heat, is expected to achieve a conversion efficiency of over 80%. Regarding the energy efficiency of the exothermic process of calcium oxide hydration, when external heat is required to convert liquid water into water vapor, the energy release efficiency does not exceed 60%. This invention can directly utilize the high-temperature water vapor discharged during the energy release process of a medium-high temperature hydrogen fuel cell, and is expected to achieve an energy release efficiency of over 80%. When the calcium carbide slag contains 80% calcium hydroxide and 10% calcium carbonate, after five heat storage cycles in a carbon dioxide-free atmosphere, the calcium hydroxide content in the calcium carbide slag can increase to 87%, while the calcium carbonate content can decrease to 3%. When the number of cycles is further increased, the increase in calcium hydroxide content and the decrease in calcium carbonate content in the calcium carbide slag are not significant and can be maintained at a stable ratio. Therefore, this invention patent couples a medium-high temperature hydrogen fuel cell and a calcium carbide slag thermochemical energy storage system through high-energy material flow, and discovers the self-compensation effect of calcium carbide slag in the heat storage cycle. This not only improves the energy efficiency of each subsystem, but also achieves high energy efficiency of the coupled system and performance improvement (purification) of the calcium carbide slag heat storage material. Attached Figure Description

[0019] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0020] Figure 1 This is a process flow diagram of the power generation process of the high-efficiency power generation system coupled with hydrogen fuel cells and carbide slag thermochemical energy storage in an embodiment of the present invention.

[0021] Among them, 1-hydrogen storage tank, 2-oxygen storage tank, 3-medium and high temperature fuel cell, 4-high temperature water tank, 5-water pump, 6-nitrogen source, 7-heat exchanger, 8-mixer, 9-exothermic reactor, 10-dewatering product silo of carbide slag, 11-carbide slag silo, 12-steam turbine generator, 13-nitrogen preheater.

[0022] Figure 2This is a graph showing the evolution of the thermochemical thermal energy storage performance of carbide slag in an atmosphere containing 400 ppm carbon dioxide in an embodiment of the present invention. Detailed Implementation

[0023] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0024] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0025] To simultaneously address the issues of efficient utilization of high-temperature exhaust gas (i.e., water vapor) from high-temperature hydrogen fuel cells, low-energy acquisition of gaseous reactants (i.e., water vapor) from carbide slag thermochemical energy storage systems, and the limitation of carbide slag thermal storage density by the proportion of effective thermal storage materials, this invention proposes a high-efficiency power generation process and system that couples hydrogen fuel cells and thermochemical energy storage.

[0026] A typical embodiment of the present invention provides a high-efficiency power generation process that couples hydrogen fuel cells and thermochemical energy storage, including an energy storage process and a power generation process.

[0027] The energy storage process includes an electrolysis process and a pyrolysis process. The electrolysis process involves using a portion of the electrical energy to electrolyze water to produce hydrogen and oxygen. The pyrolysis process involves using another portion of the electrical energy to heat the calcium carbide slag, causing the calcium hydroxide in it to absorb heat and dehydrate to form calcium carbide slag dehydration products and liquid water.

[0028] The power generation process is as follows: hydrogen and oxygen generated during the electrolysis process are fed into a hydrogen fuel cell to undergo an electrochemical reaction to generate electricity, and high-temperature water vapor at 600-800°C is discharged. The high-temperature water vapor is used to vaporize the liquid water generated during the pyrolysis process to form reaction steam. A gas without carbon dioxide is added to the reaction steam to form a mixed gas. The partial pressure of the reaction steam in the mixed gas is adjusted by the gas without carbon dioxide. The mixed gas with adjusted partial pressure undergoes an exothermic reaction with the dehydration product of the carbide slag to generate heat energy. The generated heat energy is used to generate electricity using a steam turbine generator.

[0029] This invention proposes coupling a medium-high temperature hydrogen fuel cell with a calcium carbide slag thermochemical energy storage system. The high-temperature exhaust gas (i.e., water vapor) from the medium-high temperature hydrogen fuel cell is used for the exothermic process of the calcium carbide slag thermochemical energy storage system (i.e., the exothermic hydration reaction of calcium oxide and water vapor), thereby achieving full utilization of matter and energy and ultimately improving the energy efficiency of the energy release process of both the medium-high temperature hydrogen fuel cell and the calcium carbide slag thermochemical energy storage system. Calcium hydroxide in calcium carbide slag undergoes carbonation upon contact with carbon dioxide due to atmospheric storage, resulting in a discontinuous calcium carbonate shell on the surface of the calcium hydroxide particles. This invention, through experimental research, reveals for the first time that, within the temperature range suitable for calcium hydroxide / calcium oxide thermochemical heat storage cycles, the calcium carbonate shell in calcium carbide slag can decompose into an effective heat storage material, namely calcium hydroxide, under the catalytic action of water molecules during heat storage and release. Specifically, during heat storage, calcium hydroxide in calcium carbide slag dehydrates into calcium oxide. The vapor generated during dehydration can be adsorbed by the calcium carbonate shell, while the calcium carbonate can decompose into calcium oxide at a lower temperature under the catalytic action of water molecules. During the exothermic process, the calcium carbonate shell decomposes under the catalysis of the high-humidity atmosphere provided by the hydrogen fuel cell, producing calcium oxide. This calcium oxide rapidly combines with water molecules to form calcium hydroxide. Therefore, the calcium carbonate shell in the carbide slag gradually disappears during the cyclic heat storage process, leading to a gradual increase in the calcium hydroxide content, which improves the heat storage density and extends the service life of the carbide slag. The self-compensating effect of the carbide slag described above occurs only when the atmosphere is free of carbon dioxide; therefore, air cannot be used in this process.

[0030] In some embodiments, the gas that does not contain carbon dioxide is nitrogen.

[0031] In some embodiments, the partial pressure of the reaction vapor in the mixed gas is adjusted by using a gas that does not contain carbon dioxide, so that the temperature of the exothermic reaction process of the reaction vapor is 480–520°C.

[0032] In some embodiments, the exhaust gas following the exothermic reaction is used to preheat a gas that does not contain carbon dioxide, thereby achieving cascaded energy utilization.

[0033] In some embodiments, the reaction vapor also includes high-temperature steam obtained after heat exchange with liquid water. This is more conducive to the efficient utilization of high-temperature steam in high-temperature hydrogen fuel cells.

[0034] In some embodiments, the electric heating temperature during the electric heating of carbide slag is 400–550°C.

[0035] Another embodiment of the present invention provides a high-efficiency power generation system coupling a hydrogen fuel cell and thermochemical energy storage, for realizing the above-mentioned high-efficiency power generation process coupling a hydrogen fuel cell and thermochemical energy storage, comprising:

[0036] The water electrolysis hydrogen production device is used to realize the electrolysis process of the energy storage process, and stores the generated hydrogen and oxygen in hydrogen storage tanks and oxygen storage tanks respectively.

[0037] Hydrogen fuel cell power generation device, which uses hydrogen in hydrogen storage tank and oxygen in oxygen storage tank to realize the electrochemical reaction of the power generation process to generate electricity and high temperature water vapor.

[0038] Thermochemical energy storage and power generation device is used to realize the pyrolysis process of energy storage and the process of generating heat energy by using high-temperature water vapor, dehydrated carbide slag products and liquid water generated by hydrogen fuel cell power generation device to produce heat energy, and using the generated heat energy to generate electricity by steam turbine generator.

[0039] In some embodiments, a heat exchanger is included, in which high-temperature water vapor generated by the hydrogen fuel cell power generation device and liquid water generated by dehydration of carbide slag are exchanged for heat.

[0040] In some embodiments, a mixer is included to vaporize liquid water generated during pyrolysis using high-temperature steam to form reaction steam, and then the reaction steam is mixed with a carbon dioxide-free gas in the mixer and then delivered to a thermochemical energy storage and power generation device.

[0041] In some embodiments, a gas preheater is included, through which the exhaust gas from the thermochemical energy storage power generation device is preheated to a carbon dioxide-free gas, and then the preheated nitrogen gas is mixed with the reaction vapor and delivered to the thermochemical energy storage power generation device.

[0042] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0043] Example

[0044] When renewable energy generation in the power grid exceeds electricity demand, on the one hand, high-purity hydrogen and oxygen are produced using water electrolysis technology and stored in hydrogen storage tank 1 and oxygen storage tank 2 respectively. On the other hand, electricity is used to heat carbide slag to induce an endothermic dehydration reaction, with the heating temperature ranging from 400℃ to 550℃. Simultaneously, the dehydration product of carbide slag, mainly composed of calcium oxide, and the condensed liquid water are stored at elevated temperatures in carbide slag dehydration product silo 10 and high-temperature water tank 4 respectively. When renewable energy generation in the power grid is lower than electricity demand, such as... Figure 1As shown, hydrogen and oxygen from hydrogen storage tank 1 and oxygen storage tank 2 are supplied to the anode and cathode of the medium-high temperature fuel cell 3, respectively. Through an electrochemical reaction, the chemical energy of hydrogen and oxygen is directly converted into electrical energy. High-temperature steam (approximately 600-800℃) discharged from the medium-high temperature fuel cell 3 enters heat exchanger 7, and after heat exchange, it enters mixer 8. High-temperature water (approximately 90℃) from high-temperature water tank 4 enters heat exchanger 7 via water pump 5. The high-temperature water absorbs heat from the high-temperature steam to vaporize, and then enters mixer 8. Since the equilibrium temperature of the calcium oxide hydration reaction is related to the vapor partial pressure of the reaction atmosphere, under one atmosphere of pressure, the equilibrium temperature corresponding to a pure vapor atmosphere is 520℃. Therefore, to adjust the exothermic temperature, nitrogen needs to be introduced into the process to control the vapor partial pressure and thus the equilibrium temperature. Nitrogen gas (approximately 25°C) from nitrogen source 6 enters nitrogen preheater 13, where it is preheated using the high-temperature exhaust gas (approximately 480-520°C) from exothermic reactor 9. The preheated nitrogen then enters mixer 8. Mixer 8 mixes water vapor and nitrogen, ensuring the temperature of the mixed gas is below the equilibrium temperature of the calcium oxide hydration reaction corresponding to the vapor partial pressure of the mixed gas. This guarantees that the mixed gas can undergo an exothermic hydration reaction in exothermic reactor 9. The calcium carbide slag dewatering product silo 10 provides a continuous and stable supply of material to exothermic reactor 9. In exothermic reactor 9, calcium oxide reacts with water vapor in the mixed gas, converting the stored chemical energy into heat energy. The heat energy released in exothermic reactor 9 is absorbed by the working fluid in turbine generator 12 for power generation, while the calcium carbide slag produced by the reaction is stored in calcium carbide slag silo 11 under insulated conditions. The remaining high-temperature exhaust gas (approximately 480-520°C) that did not participate in the reaction in the exothermic reactor 9 enters the nitrogen preheater 13 to preheat the ambient-temperature nitrogen from the nitrogen source 6.

[0045] Based on estimations, the total conversion efficiency of the hydrogen fuel cell module in this process can reach over 80%, and the energy release efficiency of the carbide slag thermochemical energy storage module can reach over 80%.

[0046] The evolution of multi-cycle thermochemical thermal storage performance of calcium carbide slag in atmospheres containing 400 ppm carbon dioxide is as follows: Figure 2 As shown, when the calcium carbide slag contains 80% calcium hydroxide and 10% calcium carbonate, after 5 cycles in a carbon dioxide-free atmosphere, the calcium hydroxide content in the calcium carbide slag can increase to 87%, while the calcium carbonate content will decrease to 3%. However, in an atmosphere containing 400 ppm carbon dioxide, the calcium hydroxide content gradually decreases with the increase of the number of cycles. After 20 cycles, the calcium hydroxide content in the calcium carbide slag decreases to 20%, while the calcium carbonate content increases to 72%. This indicates that under carbon dioxide-free atmospheric conditions, the calcium carbide slag produces a self-compensating effect in the thermal storage cycle.

[0047] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-efficiency power generation process coupling hydrogen fuel cells and thermochemical energy storage, characterized in that, Includes energy storage and power generation processes; The energy storage process includes an electrolysis process and a pyrolysis process. The electrolysis process involves using a portion of the electrical energy to electrolyze water to produce hydrogen and oxygen. The pyrolysis process involves using another portion of the electrical energy to heat the calcium carbide slag, causing the calcium hydroxide in it to absorb heat and dehydrate to form calcium carbide slag dehydration products and liquid water. The power generation process is as follows: hydrogen and oxygen generated during the electrolysis process are fed into a hydrogen fuel cell to undergo an electrochemical reaction to generate electricity, and high-temperature water vapor at 600-800°C is discharged. The high-temperature water vapor is used to vaporize the liquid water generated during the pyrolysis process to form reaction steam. A gas without carbon dioxide is added to the reaction steam to form a mixed gas. The partial pressure of the reaction steam in the mixed gas is adjusted by the gas without carbon dioxide. The mixed gas with adjusted partial pressure undergoes an exothermic reaction with the dehydration product of the carbide slag to generate heat energy. The generated heat energy is used to generate electricity using a steam turbine generator.

2. The high-efficiency power generation process coupled with hydrogen fuel cells and thermochemical energy storage as described in claim 1, characterized in that, The gas that does not contain carbon dioxide is nitrogen.

3. The high-efficiency power generation process coupled with hydrogen fuel cells and thermochemical energy storage as described in claim 1, characterized in that, The partial pressure of the reaction vapor in the mixed gas is adjusted by using a gas that does not contain carbon dioxide, so that the temperature of the exothermic reaction process of the reaction vapor is 480-520℃.

4. The high-efficiency power generation process coupled with hydrogen fuel cells and thermochemical energy storage as described in claim 1, characterized in that, The exhaust gas after the exothermic reaction is used to preheat a gas that does not contain carbon dioxide, so as to achieve the cascade utilization of energy.

5. The high-efficiency power generation process coupled with hydrogen fuel cells and thermochemical energy storage as described in claim 1, characterized in that, The reaction steam also includes high-temperature steam after heat exchange with liquid water, which is more conducive to the efficient utilization of high-temperature steam in high-temperature hydrogen fuel cells.

6. The high-efficiency power generation process coupled with hydrogen fuel cells and thermochemical energy storage as described in claim 1, characterized in that, The electric heating temperature during the process of electrically heating carbide slag is 400-550℃.

7. A high-efficiency power generation system coupling a hydrogen fuel cell and thermochemical energy storage, characterized in that, The efficient power generation process for realizing the coupled hydrogen fuel cell and thermochemical energy storage as described in any one of claims 1 to 6 includes: The water electrolysis hydrogen production device is used to realize the electrolysis process of the energy storage process, and stores the generated hydrogen and oxygen in hydrogen storage tanks and oxygen storage tanks respectively. Hydrogen fuel cell power generation device, which uses hydrogen in hydrogen storage tank and oxygen in oxygen storage tank to realize the electrochemical reaction of the power generation process to generate electricity and high temperature water vapor; Thermochemical energy storage and power generation device is used to realize the pyrolysis process of energy storage and the process of generating heat energy by using high-temperature water vapor, dehydrated carbide slag products and liquid water generated by hydrogen fuel cell power generation device to produce heat energy, and using the generated heat energy to generate electricity by steam turbine generator.

8. The high-efficiency power generation system coupled with hydrogen fuel cells and thermochemical energy storage as described in claim 7, characterized in that, The device includes a heat exchanger in which high-temperature steam generated by the hydrogen fuel cell power generation device and liquid water generated by dehydration of carbide slag exchange heat.

9. The high-efficiency power generation system coupled with hydrogen fuel cells and thermochemical energy storage as described in claim 7, characterized in that, It includes a mixer that uses high-temperature steam to vaporize the liquid water produced during pyrolysis to form reaction steam. The reaction steam is then mixed with a carbon dioxide-free gas in the mixer and then delivered to a thermochemical energy storage and power generation device.

10. The high-efficiency power generation system coupled with hydrogen fuel cells and thermochemical energy storage as described in claim 7, characterized in that, The device includes a gas preheater. The exhaust gas from the thermochemical energy storage power generation device is preheated by the gas preheater to remove carbon dioxide. The preheated nitrogen gas is then mixed with the reaction vapor and delivered to the thermochemical energy storage power generation device.

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