Supercritical CO2 circulation and water electrolysis hydrogen production coupled alcohol-electricity co-production system and method

Abstract

According to the supercritical CO2 circulation and water electrolysis hydrogen production coupled alcohol-electricity co-production system and method, water in an electrolytic bath is electrolyzed through wind and light abandoned electricity, and oxygen and hydrogen are generated. Oxygen and coal are subjected to pure oxygen gasification in a gasification furnace, and generated gasified gases (mainly including methane CH4, hydrogen H2 and carbon monoxide CO) are subjected to direct-fired supercritical CO2 circulation for power generation. Waste gas exhausted by the turbine is subjected to heat recovery through the heat regenerator, water is condensed in the condenser, and remaining CO2 is fed into the gas tank to be stored. One part of CO2 is pressurized by a compressor and then is fed into the combustion chamber through a heat regenerator, and the other part of CO2 and H2 are catalyzed to synthesize methane. According to the system, wind and light abandoned electricity can be converted into hydrogen energy to be stored, efficient clean power generation of coal and synthesis of green methanol are achieved through direct-fired supercritical CO2 circulation, and the green methanol / electricity co-production system with zero carbon emission is formed.

Description

Technical Field

[0001] The present invention belongs to the field of clean energy utilization and energy storage, and in particular relates to an alcohol-electricity cogeneration system and method that couples a direct-fired supercritical CO2 cycle with water electrolysis to produce hydrogen. Background Art

[0002] At present, the problem of power abandonment of renewable energy wind and solar power generation faces many challenges. For example, wind and solar power generation are greatly affected by natural conditions, and the power generation is intermittent and volatile, making it difficult to match the real-time demand of the power grid; the cost of large-scale energy storage technologies (such as battery storage, pumped storage, etc.) is still relatively high, making it difficult to deploy them on a large scale economically and effectively; the existing power grid infrastructure lacks the regulatory capacity and flexibility to adapt to the access and fluctuations of large-scale renewable energy; the power market is unable to absorb these unstable electric energies affected by natural factors, so some wind and solar power cannot be effectively utilized.

[0003] However, for this part of wind and solar power curtailment, energy storage technology can effectively solve its instability disadvantage. Some new energy storage technologies (such as hydrogen energy storage) are already in the research and development stage. The principle is to convert unstable renewable energy into another clean energy that can be stored and transported for a long time, thereby achieving the purpose of storing renewable energy across time and regions.

[0004] In this regard, we can consider rationally utilizing the abandoned wind and solar power to transform it into other stable energy storage. Electrolysis of water will produce two gases, hydrogen and oxygen. In order to make full use of oxygen in addition to hydrogen, a clean energy, we can consider gasifying oxygen with coal and then burning it in oxygen-enriched form to produce supercritical carbon dioxide, a working fluid with superior thermophysical properties, which can be used in turbines to produce stable electricity. The emitted carbon dioxide can also react with hydrogen to synthesize methanol, another clean energy that is more suitable for storage than hydrogen. This can solve the problem of abandoned wind and solar power and transform it into clean energy that is easy to store and transport. It can also generate stable electricity to achieve the effect of "peak shaving and valley filling" and balance the power grid during peak electricity consumption periods.

[0005] In summary, the problems existing in the existing technologies are: low efficiency in energy conversion and utilization, especially in traditional coal-fired power generation and steam power cycles. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide an alcohol-electricity cogeneration system and method that couples direct-fired supercritical CO2 circulation with water electrolysis to produce hydrogen, which can improve the utilization rate of renewable energy, reduce unnecessary carbon emissions, and achieve energy conservation and emission reduction.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is: The alcohol-electricity cogeneration system that couples direct-fired supercritical CO2 cycle with water electrolysis hydrogen production includes an electrolyzer, a gasifier, a combustion chamber, a turbine, a regenerator, a condenser, a compressor, a fixed-bed reactor, a hydrogen storage tank, an oxygen storage tank, and a carbon dioxide storage tank; The hydrogen and oxygen generated by electrolyzing water in the electrolytic cell are connected to a hydrogen storage tank and an oxygen storage tank respectively; The combustion chamber is connected to the gasifier and the oxygen storage tank; The turbine is used to pass the supercritical carbon dioxide and water vapor obtained in the combustion chamber into the turbine to generate power, and the turbine is connected to the regenerator and the generator to form a direct-fired supercritical CO cycle; The regenerator utilizes the waste heat of the gas after the turbine has done work to reheat the supercritical carbon dioxide before it is introduced into the combustion chamber, and the regenerator is then connected to the condenser; The compressor pressurizes the carbon dioxide in the carbon dioxide storage tank to form supercritical carbon dioxide and sends it to the regenerator for preheating, and then mixes it with the oxygen sent from the oxygen storage tank before passing it into the combustion chamber; The fixed bed reactor is connected with a carbon dioxide storage tank and a hydrogen storage tank, and is used for catalytic synthesis of methanol by hydrogen and carbon dioxide.

[0008] Preferably, the system further comprises a coal bunker, which is used to store coal before the gasification furnace reaction and to deliver the coal for gasification reaction when needed.

[0009] Preferably, the system further comprises a generator connected to the turbine, which utilizes supercritical carbon dioxide to do work and obtains output electrical energy.

[0010] Preferably, the circulating working fluid of the system is supercritical carbon dioxide, which is circulated in the combustion chamber, turbine, regenerator, condenser, carbon dioxide storage tank and compressor; while the working fluid used in the fixed bed reactor is part of the carbon dioxide stored in the carbon dioxide storage tank after condensation by the condenser.

[0011] Preferably, the electrolyzer uses a wind turbine and / or a solar photovoltaic power generation device as an energy source to electrolyze water to generate hydrogen and oxygen.

[0012] An operation method of an alcohol-electricity cogeneration system coupled with a direct-fired supercritical CO2 cycle and water electrolysis hydrogen production comprises the following stages: In the renewable energy water electrolysis stage, the wind and solar power that cannot be used by the power grid is first connected to the water electrolysis device, and the wind turbines and photovoltaic power generation devices are connected to the electrolyzer when they are generating unstable electricity, and two parts of gas, hydrogen and oxygen, are electrolyzed; and these two gases are stored in hydrogen storage tanks and oxygen storage tanks respectively for subsequent gasification, combustion, and methanol synthesis processes; in this process, unstable renewable energy is not wasted, but is fully utilized.

[0013] In the coal pure oxygen gasification stage, the coal in the coal bunker is fed into the gasifier, and then the oxygen in the oxygen storage tank is introduced into the gasifier to gasify into synthesis gases such as hydrogen, carbon monoxide, and methane, so as to facilitate the subsequent oxygen-rich combustion to generate supercritical carbon dioxide for work.

[0014] In the oxygen-rich combustion stage, after the coal in the gasifier is gasified, the combustion chamber is opened, the oxygen storage tank is connected to the combustion chamber, and sufficient oxygen is introduced to ensure oxygen-rich combustion of carbon monoxide and other synthesis gases to generate supercritical carbon dioxide. In the high-temperature and high-pressure combustion chamber, the synthesis gas reacts and burns with sufficient oxygen to generate a large amount of supercritical carbon dioxide and water vapor.

[0015] In the turbine power stage, the working medium in the combustion chamber is introduced into the turbine to perform work. At the same time, the turbine is connected to the generator. Supercritical carbon dioxide has excellent thermophysical properties, so the energy output of the generator is stable. During the cycle heat recovery stage, the carbon dioxide and water discharged after the turbine completes its work will first pass through the recuperator to absorb the remaining heat. This heat will be used in the subsequent cycle to regenerate supercritical carbon dioxide as heating; after passing through the recuperator, the gas will pass into the condenser to reduce the temperature and condense to generate condensed water and discharge the system, while the remaining carbon dioxide will be separated and stored in a carbon dioxide storage tank for subsequent supercritical carbon dioxide circulation and methanol synthesis.

[0016] In the supercritical carbon dioxide power cycle stage, part of the carbon dioxide stored in the supercritical carbon dioxide storage tank is passed through a compressor for pressurization. The carbon dioxide with increased pressure absorbs heat through a regenerator and is regenerated into supercritical carbon dioxide. It is passed into the combustion chamber and combined with oxygen-enriched combustion to generate more supercritical carbon dioxide for work. It is then passed into the turbine again to work. The entire system completes the supercritical carbon dioxide power cycle. During the methanol synthesis stage, another part of the carbon dioxide in the carbon dioxide storage tank is introduced into the fixed bed reactor, and the fixed bed reactor is connected to the hydrogen storage tank; hydrogen and dioxide are synthesized into clean energy methanol under the catalysis of the catalyst to complete energy storage. The entire system completes energy storage and can transport or store methanol, a clean energy, across seasons.

[0017] The present invention can achieve the following beneficial effects: (1) It can convert the abandoned wind and solar power that cannot be absorbed by the power grid into hydrogen energy through water electrolysis for storage, which can achieve long-term energy storage across regions and seasons, and then generate electricity during peak electricity consumption periods, effectively balancing the supply and demand relationship in the power system, improving energy utilization efficiency, and having high sustainability and environmental protection.

[0018] (2) The oxygen generated by electrolysis of water is sent to the gasifier and combustion furnace to achieve pure oxygen gasification and oxygen-enriched combustion of coal, which is beneficial to improve combustion efficiency and reduce the generation of dust and pollutants. At the same time, the direct-fired supercritical CO2 cycle is used for power generation. Compared with the traditional water steam power cycle, it has the advantages of high efficiency, high power density, long operating life, and compact system equipment.

[0019] (3) The hydrogen produced by water electrolysis is combined with the exhaust gas from the direct-fired supercritical CO2 cycle to synthesize methanol, thereby achieving the production of green methanol.

[0020] (4) The entire system uses wind and solar power and coal as energy input, ultimately generating electricity and methanol. The entire system has the advantages of high efficiency, compact equipment, and zero carbon emissions, achieving the co-production of green methanol / electricity. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: Figure 1 This is a system structure diagram of the present invention.

[0022] In the figure: 1-electrolyzer, 2-gasifier, 3-combustion chamber, 4-turbine, 5-regenerator, 6-condenser, 7-compressor, 8-fixed bed reactor, 9-hydrogen storage tank, 10-oxygen storage tank, 11-coal bunker, 12-generator, 13-carbon dioxide storage tank. DETAILED DESCRIPTION

[0023] The preferred solution is Figure 1 As shown, the alcohol-electricity cogeneration system of direct-fired supercritical CO2 cycle coupled with water electrolysis hydrogen production includes an electrolyzer 1, a gasifier 2, a combustion chamber 3, a turbine 4, a regenerator 5, a condenser 6, a compressor 7, a fixed bed reactor 8, a hydrogen storage tank 9, an oxygen storage tank 10 and a carbon dioxide storage tank 13; The electrolyzer 1 uses wind and solar power abandonment, i.e., wind turbines and solar photovoltaic power generation devices, as energy sources to electrolyze water to generate hydrogen and oxygen, which are connected to a hydrogen storage tank 9 and an oxygen storage tank 10, respectively.

[0024] The main function of the gasifier 2 is to convert solid fuels such as coal into combustible gas. By controlling the supply of oxygen, the gasifier 2 can adjust the degree of reaction to ensure that the generated gas composition meets expectations. The gasifier 2 is connected to the oxygen storage tank 10 and the coal bunker 11, and reacts with coal through high temperature and high pressure to generate synthesis gas (mainly methane CH4, hydrogen H2, carbon monoxide CO) in the gasifier.

[0025] The combustion chamber 3 is connected to the gasifier 2 and the oxygen storage tank 10, and the synthesis gas CO, H2, CH4 generated by the reaction is combusted with pure oxygen at high temperature to obtain supercritical carbon dioxide and water vapor.

[0026] The turbine 4 is used to pass the supercritical carbon dioxide and water vapor obtained in the combustion chamber 3 into the combustion chamber to generate power. The turbine 4 is connected to the regenerator 5 and the generator 12, and finally forms a direct-fired supercritical CO2 cycle.

[0027] The regenerator 5 utilizes the waste heat of the gas after the turbine 4 has done work to reheat the supercritical carbon dioxide before it is introduced into the combustion chamber 3 , and is connected to the condenser 6 .

[0028] The condenser 6 is used to condense the exhaust gas into water and carbon dioxide, thereby separating the carbon dioxide from the water and storing the carbon dioxide.

[0029] The compressor 7 pressurizes the carbon dioxide in the carbon dioxide storage tank 13 to form supercritical carbon dioxide and sends it to the regenerator 5 for preheating, and then mixes it with the oxygen sent from the oxygen storage tank 10 and then passes it into the combustion chamber 3 to provide an oxidant for oxygen-enriched combustion of coal and achieve temperature regulation.

[0030] The fixed bed reactor 8 is connected to the carbon dioxide storage tank 13 and the hydrogen storage tank 9, and is used to catalyze the synthesis of methanol by hydrogen and carbon dioxide. The catalyst used in the catalytic reaction in the fixed bed reactor is a copper-based catalyst.

[0031] The coal bunker 11 is used to store coal before the reaction in the gasifier 2, and to deliver coal for gasification reaction when needed.

[0032] The generator 12 is connected to the turbine 4 and uses supercritical carbon dioxide to do work to obtain output electrical energy.

[0033] In the cycle of outputting electrical energy through work, the main circulating working fluid is supercritical carbon dioxide, which is circulated in the combustion chamber 3, the turbine 4, the regenerator 5, the condenser 6, the carbon dioxide storage tank 13, and the compressor 7, while the working fluid used in the fixed bed reactor 8 is part of the carbon dioxide stored in the carbon dioxide storage tank 13 after condensation by the condenser 6.

[0034] Furthermore, since wind turbines and solar photovoltaic power generation devices are greatly affected by natural factors and their power generation is unstable, they cannot be directly connected to the power grid for power generation. This unstable electric energy is used in the electrolytic cell 1 to electrolyze hydrogen and oxygen, and the oxygen generated can be used for subsequent coal gasification and combustion, and the hydrogen can be used to catalyze the synthesis of methanol with the carbon dioxide generated by the circulation reaction.

[0035] Furthermore, after coal and part of the oxygen in the oxygen storage tank 10 are introduced into the gasifier 2 to gasify and obtain synthesis gas, the synthesis gas is again introduced into the combustion chamber 3 for high-pressure oxygen-rich combustion to generate supercritical carbon dioxide and water vapor. The supercritical carbon dioxide generated in this process has the advantage of higher efficiency when introduced into the turbine 4 to perform work, thereby making the power generation efficiency higher.

[0036] Furthermore, the exhaust waste heat after the turbine 4 works is utilized by the regenerator 5, and then the supercritical carbon dioxide is circulated for heating, thereby avoiding energy waste. The exhaust gas after the regenerator 5 is condensed by the condenser 6 to generate condensed water and carbon dioxide, which can separate the water and carbon dioxide, and store the carbon dioxide in the carbon dioxide storage tank 13.

[0037] Furthermore, a portion of the carbon dioxide stored in the carbon dioxide storage tank 13 is pressurized by the compressor 7 and heated by the regenerator 5 to obtain supercritical carbon dioxide again, which is introduced into the combustion chamber 3 to adjust the combustion temperature and obtain high-temperature supercritical CO2 gas.

[0038] Furthermore, another part of the carbon dioxide in the carbon dioxide storage tank 13 is connected to the fixed bed reactor 8, and introduced into the hydrogen produced by the electrolytic cell 1, and methanol is synthesized under the catalysis of the copper-based catalyst. The methanol can be stored as a clean energy.

[0039] The system operation phases include the following: Phase 1: Renewable energy electrolysis water phase. First, connect the wind and solar power that cannot be used by the power grid to the water electrolysis device. Connect the wind turbine and photovoltaic power generation device to the electrolyzer 1 when they are unstable, and electrolyze two gases, hydrogen and oxygen. These two gases are stored in the hydrogen storage tank 9 and the oxygen storage tank 10 respectively, for the subsequent gasification, combustion, and methanol synthesis process. In this process, the unstable renewable energy is not wasted, but fully utilized.

[0040] In the second stage, the coal pure oxygen gasification stage, the coal in the coal bunker 11 (the type of coal can be high-ash coal and high-moisture coal) is fed into the gasifier 2, and then the oxygen in the oxygen storage tank 10 is introduced into the gasifier 2 for gasification to generate hydrogen, carbon monoxide, methane and other synthetic gases, so as to facilitate the subsequent oxygen-enriched combustion to generate supercritical carbon dioxide for work.

[0041] Stage three is the oxygen-enriched combustion stage. At this time, after the coal in the gasifier 2 is gasified, the combustion chamber 3 is opened, the oxygen storage tank 10 is connected to the combustion chamber 3, and sufficient oxygen is introduced to ensure oxygen-enriched combustion of carbon monoxide and other synthetic gases to generate supercritical carbon dioxide. In the high-temperature and high-pressure combustion chamber, the synthetic gas reacts and burns with sufficient oxygen to generate a large amount of supercritical carbon dioxide and water vapor.

[0042] In stage 4, the turbine works, the working fluid in the combustion chamber 3 is introduced into the turbine 4 to work. At the same time, the turbine 4 is connected to the generator 12. Supercritical carbon dioxide has excellent thermophysical properties. Since the energy output of the generator 12 is stable, it can be connected to the power grid to "shave the peak and fill the valley" during peak electricity consumption to reduce the load on the power grid.

[0043] Phase 5, the cycle heat recovery phase, after the turbine 4 completes the work, the carbon dioxide and water discharged will first pass through the regenerator 5 to absorb the remaining heat, which will be used for subsequent circulation to regenerate supercritical carbon dioxide as heating. The gas after passing through the regenerator 5 will pass into the condenser 6 to reduce the temperature and condense, generating condensed water to be discharged from the system, while the remaining carbon dioxide will be separated and stored in the carbon dioxide storage tank 13 for subsequent supercritical carbon dioxide circulation and methanol synthesis.

[0044] In stage six, the supercritical carbon dioxide power cycle stage, a part of the carbon dioxide stored in the supercritical carbon dioxide storage tank 13 is passed into the compressor 7 for pressurization. The carbon dioxide with increased pressure after pressurization absorbs heat through the regenerator 5, and is regenerated into supercritical carbon dioxide, which is passed into the combustion chamber 3 and burned with oxygen-rich gas to generate more supercritical carbon dioxide for doing work, and then is passed into the turbine again to do work. The whole system completes the supercritical carbon dioxide power cycle.

[0045] In the seventh stage, the methanol synthesis stage, another part of the carbon dioxide in the carbon dioxide storage tank 13 is introduced into the fixed bed reactor 8, and the fixed bed reactor 8 is connected to the hydrogen storage tank 10. Hydrogen and carbon dioxide are synthesized into clean energy methanol under the catalysis of the catalyst (copper-based catalyst), completing energy storage. The entire system completes energy storage, and can transport or store methanol, a clean energy, across seasons, achieving the goal of carbon zero emission energy storage.

[0046] The present invention improves the utilization rate of unstable energy sources such as wind energy and solar energy that are disturbed by natural factors, and the supercritical carbon dioxide generated in the process can be used as a good working fluid for turbine work, driving the motor to generate stable power and balance the power grid. The novel system for producing green methanol by using wind and solar power to achieve zero carbon emissions uses wind and solar power to electrolyze water to produce hydrogen and oxygen. Synthetic gas such as carbon monoxide and hydrogen is produced by oxygen and coal gasification reaction, and supercritical carbon dioxide and water vapor are produced by oxygen-enriched combustion, which are passed into the turbine and incorporated into the generator to do work and provide stable electric energy. The gas that has done work is stored in the regenerator for residual heat, condensed and discharged through the condenser, and the remaining carbon dioxide is returned to the combustion chamber by a compressor for pressurization and reheating by the regenerator to generate supercritical carbon dioxide that can do work again, and the other part is catalytically synthesized with hydrogen produced by electrolysis on a fixed bed reactor to synthesize methanol that is easy to store and transport. The system not only realizes the storage of renewable energy, but also can convert unstable renewable energy into energy that can output work stably. In addition, it realizes zero emissions to the outside, and only condensed water is generated in the process.

[0047] The above embodiments are only preferred technical solutions of the present invention and should not be regarded as limiting the present invention. The protection scope of the present invention shall be the technical solutions recorded in the claims, including equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. Alcohol-electricity cogeneration system with direct-fired supercritical CO2 cycle coupled with water electrolysis to produce hydrogen, characterized by: It comprises an electrolyzer (1), a gasifier (2), a combustion chamber (3), a turbine (4), a regenerator (5), a condenser (6), a compressor (7), a fixed bed reactor (8), a hydrogen storage tank (9), an oxygen storage tank (10) and a carbon dioxide storage tank (13); The hydrogen and oxygen generated by the electrolysis of water in the electrolytic cell (1) are connected to a hydrogen storage tank (9) and an oxygen storage tank (10) respectively; The combustion chamber (3) is connected to the gasifier (2) and the oxygen storage tank (10); The turbine (4) is used to pass the supercritical carbon dioxide and water vapor obtained in the combustion chamber (3) into the combustion chamber to generate power. The turbine (4) is connected to the regenerator (5) and the generator (12) to form a direct-fired supercritical CO2 cycle. The regenerator (5) utilizes the waste heat of the gas after the turbine (4) has done work to reheat the supercritical carbon dioxide before it is introduced into the combustion chamber (3). The regenerator (5) is then connected to the condenser (6); The compressor (7) pressurizes the carbon dioxide in the carbon dioxide storage tank (13) to form supercritical carbon dioxide and sends it to the regenerator (5) for preheating, and then mixes it with the oxygen sent from the oxygen storage tank (10) and then passes it into the combustion chamber (3); The fixed bed reactor (8) is connected to a carbon dioxide storage tank (13) and a hydrogen storage tank (9) and is used to catalyze the synthesis of methanol using hydrogen and carbon dioxide.

2. The alcohol-electricity cogeneration system of direct-fired supercritical CO2 cycle coupled with water electrolysis hydrogen production according to claim 1 is characterized by: It also comprises a coal bunker (11), wherein the coal bunker (11) is used to store coal before the reaction of the gasifier (2), and to deliver the coal for gasification reaction when needed.

3. The alcohol-electricity cogeneration system of direct-fired supercritical CO2 cycle coupled with water electrolysis hydrogen production according to claim 1 is characterized by: It also includes a generator (12), which is connected to the turbine (4) and uses supercritical carbon dioxide to do work to obtain output electrical energy.

4. The alcohol-electricity cogeneration system of direct-fired supercritical CO2 cycle coupled with water electrolysis hydrogen production according to claim 1 is characterized by: The circulating working fluid of the system is supercritical carbon dioxide, which is circulated in the combustion chamber (3), the turbine (4), the regenerator (5), the condenser (6), the carbon dioxide storage tank (13) and the compressor (7); and the carbon dioxide used in the fixed bed reactor (8) is part of the carbon dioxide stored in the carbon dioxide storage tank (13) after being condensed by the condenser (6).

5. The alcohol-electricity cogeneration system of direct-fired supercritical CO2 cycle coupled with water electrolysis hydrogen production according to claim 1 is characterized by: The electrolyzer (1) uses a wind turbine and / or a solar photovoltaic power generation device as an energy source to electrolyze water to generate hydrogen and oxygen.

6. The method for operating the alcohol-electricity cogeneration system of the direct-fired supercritical CO2 cycle coupled with water electrolysis hydrogen production according to claim 1 is characterized in that The following phases are included: In the renewable energy water electrolysis stage, the wind and solar power that cannot be used by the power grid is first connected to the water electrolysis device, and the wind turbine and photovoltaic power generation device are connected to the electrolyzer (1) when the power generation is unstable, and two gases, hydrogen and oxygen, are electrolyzed; and the two gases are stored in the hydrogen storage tank (9) and the oxygen storage tank (10) respectively, so as to be used in the subsequent gasification, combustion, and methanol synthesis process; in this process, the unstable renewable energy is not wasted, but fully utilized.

7. The operation method of the alcohol-electricity cogeneration system coupled with direct-fired supercritical CO2 cycle and water electrolysis hydrogen production according to claim 6 is characterized by: In the coal pure oxygen gasification stage, the coal in the coal bunker (11) is fed into the gasifier (2), and then the oxygen in the oxygen storage tank (10) is introduced into the gasifier (2) for gasification to generate synthesis gases such as hydrogen, carbon monoxide, and methane, so as to facilitate subsequent oxygen-enriched combustion to generate supercritical carbon dioxide for work.

8. The method for operating the alcohol-electricity cogeneration system of the direct-fired supercritical CO2 cycle coupled with water electrolysis hydrogen production according to claim 6 or 7, characterized in that: In the oxygen-enriched combustion stage, after the coal in the gasifier (2) is gasified, the combustion chamber (3) is opened, the oxygen storage tank (10) is connected to the combustion chamber (3), and a sufficient amount of oxygen is introduced to ensure oxygen-enriched combustion of carbon monoxide and other synthesis gases to generate supercritical carbon dioxide. In the high-temperature and high-pressure combustion chamber, the synthesis gas reacts and burns with sufficient oxygen to generate a large amount of supercritical carbon dioxide and water vapor.

9. The method for operating the alcohol-electricity cogeneration system of the direct-fired supercritical CO2 cycle coupled with water electrolysis hydrogen production according to claim 6 or 7, characterized in that: In the turbine power generation stage, the working medium in the combustion chamber (3) is introduced into the turbine (4) to perform work. At the same time, the turbine (4) is connected to the generator (12). Supercritical carbon dioxide has excellent thermophysical properties, so the energy output of the generator (12) is stable. In the cycle heat recovery stage, the carbon dioxide and water discharged after the turbine (4) completes its work will first pass through the regenerator (5) to absorb the remaining heat, which will be used for subsequent circulation to regenerate supercritical carbon dioxide as heating; after passing through the regenerator (5), the gas will pass into the condenser (6) to reduce the temperature and condense, generating condensed water and discharging it out of the system, while the remaining carbon dioxide will be separated and stored in the carbon dioxide storage tank (13) for subsequent supercritical carbon dioxide circulation and methanol synthesis.

10. The method for operating the alcohol-electricity cogeneration system of the direct-fired supercritical CO2 cycle coupled with water electrolysis hydrogen production according to claim 6 or 7, characterized in that: In the supercritical carbon dioxide power cycle stage, part of the carbon dioxide stored in the supercritical carbon dioxide storage tank (13) is introduced into the compressor (7) for pressurization. The carbon dioxide with increased pressure absorbs heat through the regenerator (5) and is regenerated into supercritical carbon dioxide. The supercritical carbon dioxide is introduced into the combustion chamber (3) and burned with oxygen to generate more supercritical carbon dioxide for doing work. The supercritical carbon dioxide is then introduced into the turbine again for doing work. The whole system completes the supercritical carbon dioxide power cycle. In the methanol synthesis stage, another portion of the carbon dioxide in the carbon dioxide storage tank (13) is introduced into the fixed bed reactor (8), and the fixed bed reactor (8) is connected to the hydrogen storage tank (10); hydrogen and carbon dioxide are synthesized into clean energy methanol under the catalysis of the catalyst, completing energy storage. The entire system completes energy storage and can transport or store methanol, a clean energy, across seasons.

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