A three-cycle power generation system integrating fuel cells and supercritical carbon dioxide electrolysis

Abstract

The present invention discloses a water electrolysis three-cycle power generation system integrating a fuel cell and supercritical carbon dioxide, which relates to the technical field of coal-based power generation, and comprises a gasification chamber, wherein the outlet of the gasification chamber is connected to a high-temperature heat exchanger, the high-temperature heat exchanger is connected to a solid oxide fuel cell, the solid oxide fuel cell is connected to a waste heat boiler, the waste heat boiler is connected to a waste heat recovery device, and the waste heat recovery device is connected to a condenser; the present invention realizes efficient and clean utilization of coal, and CO2 in the exhaust gas can be separated from CO2 through the condensation process, and there is no need to provide a large amount of heat for the decarbonization process, thereby reducing overall energy loss, and avoiding the emission of harmful impurities in CO2 into the air, avoiding impact on the environment, and by adopting clean energy to carry out power generation work, and being able to generate sufficient electricity for its own use during the power generation process, thereby reducing power loss during the power generation process, thereby improving the power generation efficiency of the coal-fired power plant.

Description

Technical Field

[0001] The present invention relates to the technical field of coal-based power generation, in particular to a water electrolysis three-cycle power generation system integrating a fuel cell and supercritical carbon dioxide. Background Art

[0002] Coal-fired power generation dominates my country's energy mix. However, coal-fired power plants currently emit nearly 1 kg of CO2 and other pollutants for every kilowatt-hour of electricity generated. With the rapid development of the global economy and the increasingly severe environmental and climate pressures, developing clean and efficient power generation technologies has become a consensus among countries.

[0003] First, when existing coal-fired power plants generate electricity, the CO2 they produce is directly emitted into the air, which has an impact on the environment. In addition, a large amount of heat is required to decarbonize the CO2, which increases the overall energy loss.

[0004] Secondly, existing coal-fired power plants suffer from large power losses during power generation, which affects the power generation efficiency of the coal-fired power plants.

[0005] To this end, we propose a three-cycle power generation system that integrates fuel cells and supercritical carbon dioxide water electrolysis. Summary of the Invention

[0006] The present invention aims to provide a three-cycle water electrolysis power generation system integrating a fuel cell and supercritical carbon dioxide to solve the problems mentioned in the background art above, in which the CO2 generated by existing coal-fired power plants during power generation is directly discharged into the air, thereby affecting the environment, and a large amount of heat is required for decarbonization and separation of the CO2, thereby increasing overall energy loss.

[0007] Secondly, existing coal-fired power plants suffer from large power losses during power generation, thereby affecting the power generation efficiency of the coal-fired power plants.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] The three-cycle power generation system integrating fuel cells and supercritical carbon dioxide water electrolysis includes:

[0010] A gasification chamber, wherein the outlet of the gasification chamber is connected to a high-temperature heat exchanger, the high-temperature heat exchanger is connected to a solid oxide fuel cell, the solid oxide fuel cell is connected to a waste heat boiler, the waste heat boiler is connected to a waste heat recovery device, and the waste heat recovery device is connected to a condenser;

[0011] The condenser is also connected to the waste heat recovery device;

[0012] The condenser is respectively connected to a water electrolysis device, a compressor and three

[0013] The water electrolysis device is connected to a solid oxide fuel cell;

[0014] The compressor 3 is connected to the low-temperature heat exchanger 2, the low-temperature heat exchanger 2 is connected to the compressor 2, and the low-temperature heat exchanger 2 is connected to the high-temperature heat exchanger;

[0015] The second compressor is connected to the first low-temperature heat exchanger, and the first low-temperature heat exchanger is connected to the high-temperature heat exchanger;

[0016] The system also includes a CO2 cycle power generation subsystem.

[0017] As a further solution of the present invention, the water electrolysis device is powered by a wind generator and a solar cell.

[0018] As a further solution of the present invention, the high-temperature heat exchanger, the anode of the solid oxide fuel cell, the waste heat boiler, the waste heat recovery device and the condenser are connected in series to form a loop.

[0019] As a further embodiment of the present invention, the CO2 cycle power generation subsystem includes a generator body, a turbine and an air separator;

[0020] The turbine is coaxially arranged with the generator body, and the turbine is connected to the high-temperature heat exchanger;

[0021] The generator body is connected to a first compressor, and the first compressor is connected to a first low-temperature heat exchanger and a second low-temperature heat exchanger respectively.

[0022] As a further solution of the present invention, the air separator is connected to a heat exchanger body, and the heat exchanger body is connected to a waste heat boiler.

[0023] As a further embodiment of the present invention, the high-temperature heat exchanger is connected to the anode of the solid oxide fuel cell;

[0024] The water electrolysis device is connected to the cathode of the solid oxide fuel cell.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention generates synthesis gas by introducing coal and supercritical water into a gasification chamber. After the synthesis gas passes through a high-temperature heat exchanger, it enters a waste heat boiler together with H2 generated by a water electrolysis device, O2 that has not completely reacted at the cathode of a solid oxide fuel cell, and O2 from an air preheater for mixed combustion. The heat generated by the combustion in the waste heat boiler heats water to generate supercritical water, which is supplied to the gasification chamber. The flue gas generated by the combustion in the waste heat boiler passes through a waste heat recovery device to preheat the water, and then in a condenser, the flue gas is cooled and separated to form water, gaseous CO2, and clean flue gas. Part of the water separated in the condenser enters the water electrolysis device, and the other part enters the waste heat recovery device to absorb the flue gas from the waste heat boiler. The waste heat enters the waste heat boiler; the clean flue gas formed by separation in the condenser and free of impurities such as CO2, ash, sulfur, and heavy metals is discharged into the atmosphere; the gaseous CO2 formed by separation in the condenser is compressed in two stages by compressor three and compressor two, and cooled in two stages by low-temperature heat exchanger two and low-temperature heat exchanger one, and the gaseous CO2 becomes liquid CO2, which is convenient for storage and transportation. Compared with the existing ones, the present invention realizes the efficient and clean utilization of coal, and the CO2 in the exhaust gas can be separated from the CO2 through the condensation process. There is no need to provide a large amount of heat for the decarbonization process, which reduces the overall energy loss, and avoids the emission of harmful impurities in the CO2 into the air, thereby avoiding impact on the environment.

[0027] The present invention uses a wind turbine and solar cells to power a water electrolysis device. The water electrolysis device receives a portion of the water from the condenser and decomposes the water into H2 and O2. The H2 enters the waste heat boiler, and the O2 enters the cathode of the solid oxide fuel cell. In the solid oxide fuel cell, oxygen is catalytically reduced at the cathode and reacts with the synthesis gas on the anode side through the electrolyte, directly converting the chemical energy of the synthesis gas into electrical energy and generating water and CO2.

[0028] Secondly, the turbine is coaxially arranged with the generator body. The CO2 at the outlet of compressor 1 absorbs the cooling heat generated by the compression process of the gaseous CO2 through low-temperature heat exchangers 1 and 2, absorbs part of the heat of the synthesis gas through the high-temperature heat exchanger, and reaches supercriticality, expands and performs work in the turbine. The turbine rotates and drives the generator body to output electrical energy to the outside. Compared with the existing ones, the present invention adopts clean energy to perform power generation and can generate sufficient electricity for its own use during the power generation process, thereby reducing power loss during the power generation process and improving the power generation efficiency of the coal-fired power plant. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a system block diagram of a three-cycle power generation system integrating fuel cells and supercritical carbon dioxide water electrolysis.

[0030] In the figure: 1. Vaporization chamber; 2. High-temperature heat exchanger; 3. Solid oxide fuel cell; 4. Waste heat boiler; 5. Waste heat recovery device; 6. Condenser; 7. Wind turbine; 8. Solar cell; 9. Water electrolysis device; 10. Generator body; 11. Turbine; 12. Heat exchanger body; 13. Air separator; 14. Compressor 1; 15. Compressor 2; 16. Low-temperature heat exchanger 1; 17. Compressor 3; 18. Low-temperature heat exchanger 2. DETAILED DESCRIPTION

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0032] Example 1:

[0033] See also Figure 1 The present invention provides a technical solution: a water electrolysis three-cycle power generation system integrating a fuel cell and supercritical carbon dioxide, comprising a gasification chamber 1, the outlet of the gasification chamber 1 is connected to a high-temperature heat exchanger 2, the high-temperature heat exchanger 2 is connected to a solid oxide fuel cell 3, the high-temperature heat exchanger 2 is connected to the anode of the solid oxide fuel cell 3, the solid oxide fuel cell 3 is connected to a waste heat boiler 4, the waste heat boiler 4 is connected to a waste heat recovery device 5, the waste heat recovery device 5 is connected to a condenser 6; the condenser 6 is also connected to the waste heat recovery device 5; the condenser 6 is respectively connected to a water electrolysis device 9, a compressor 9 and a water electrolysis device 9. It is connected to the solid oxide fuel cell 3; the water electrolysis device 9 is connected to the cathode of the solid oxide fuel cell 3, the compressor three 17 is connected to the low-temperature heat exchanger two 18, the low-temperature heat exchanger two 18 is connected to the compressor two 15, and the low-temperature heat exchanger two 18 is connected to the high-temperature heat exchanger 2; the compressor two 15 is connected to the low-temperature heat exchanger one 16, and the low-temperature heat exchanger one 16 is connected to the high-temperature heat exchanger 2; the water electrolysis device 9 is powered by the wind turbine 7 and the solar cell 8, and the high-temperature heat exchanger 2, the anode of the solid oxide fuel cell 3, the waste heat boiler 4, the waste heat recovery device 5 and the condenser 6 are connected in series to form a loop.

[0034] Specifically, coal and supercritical water are introduced into the gasification chamber 1 to generate synthesis gas. After the synthesis gas passes through the high-temperature heat exchanger 2, it enters the waste heat boiler 4 together with the H2 generated by the water electrolysis device 9, the O2 that has not been completely reacted at the cathode of the solid oxide fuel cell 3, and the O2 from the air preheater for mixed combustion; the heat generated by the combustion in the waste heat boiler 4 heats the water to generate supercritical water, which is supplied to the gasification chamber 1; the flue gas generated by the combustion in the waste heat boiler 4 passes through the waste heat recovery device 5 to preheat the water, and then in the condenser 6, the flue gas is cooled and separated to form water, gaseous CO2 and clean flue gas; part of the water separated by the condenser 6 enters the water electrolysis device 9, and the other part enters the waste heat recovery device 5 to absorb the waste heat from the waste heat boiler 4 The flue gas enters the waste heat boiler 4 after waste heat; the clean flue gas separated by the condenser 6 and free of impurities such as CO2, ash, sulfur, and heavy metals is discharged into the atmosphere; the gaseous CO2 separated by the condenser 6 is compressed in two stages by the compressor three 17 and the compressor two 15, and cooled in two stages by the low-temperature heat exchanger two 18 and the low-temperature heat exchanger one 16, and the gaseous CO2 is converted into liquid CO2, which is convenient for storage and transportation. Compared with the existing ones, the present invention realizes the efficient and clean utilization of coal, and the CO2 in the exhaust gas can be separated from the CO2 through the condensation process, without providing a large amount of heat for the decarbonization process, reducing the overall energy loss, and avoiding the emission of harmful impurities in the CO2 into the air, thereby avoiding impact on the environment.

[0035] Example 2:

[0036] See also Figure 1 The present invention provides a technical solution: a three-cycle power generation system integrating a fuel cell and a water electrolysis system of supercritical carbon dioxide, the system also including a CO2 cycle power generation subsystem, the CO2 cycle power generation subsystem including a generator body 10, a turbine 11 and an air separator 13; the turbine 11 is coaxially arranged with the generator body 10, and the turbine 11 is connected to the high-temperature heat exchanger 2; the generator body 10 is connected to a compressor 14, and the compressor 14 is respectively connected to a low-temperature heat exchanger 16 and a low-temperature heat exchanger 2 18; the air separator 13 is connected to a heat exchanger body 12, and the heat exchanger body 12 is connected to a waste heat boiler 4.

[0037] Specifically, referring to Example 1, a wind turbine 7 and a solar cell 8 are used to power a water electrolysis device 9. The water electrolysis device 9 receives a portion of the water from the condenser 6 and decomposes the water into H2 and O2. The H2 enters the waste heat boiler 4, and the O2 enters the cathode of the solid oxide fuel cell 3. In the solid oxide fuel cell 3, oxygen is catalytically reduced at the cathode and reacts with the synthesis gas on the anode side through the electrolyte, directly converting the chemical energy of the synthesis gas into electrical energy and generating water and CO2.

[0038] Secondly, the turbine 11 is arranged coaxially with the generator body 10. The CO2 at the outlet of the compressor 14 absorbs the cooling heat generated by the compression process of the gaseous CO2 through the low-temperature heat exchanger 16 and the low-temperature heat exchanger 2 18, absorbs part of the heat of the synthesis gas through the high-temperature heat exchanger 2, and reaches supercriticality, and expands and performs work in the turbine 11. The turbine 11 rotates and drives the generator body 10 to output electrical energy to the outside. Compared with the existing ones, the present invention adopts clean energy to perform power generation, and can generate sufficient electricity for its own use during the power generation process, thereby reducing the power loss in the power generation process and improving the power generation efficiency of the coal-fired power plant.

[0039] Based on Example 1 and Example 2, CO2 has a critical temperature of 32°C and a critical pressure of 7.38 MPa. It can be cooled to its critical temperature by water or air at ambient temperature. The supercritical carbon dioxide circulation power generation system uses carbon dioxide as a circulating working fluid, converts thermal energy into mechanical energy, drives turbine 11 to drive the generator to generate electricity, and has the characteristics of cleanliness, high efficiency, and small system size. It is a new power generation technology with great development prospects. The supercritical CO2 circulation power generation system has a wide range of heat source temperatures. The system integrates supercritical CO2 circulation technology and can achieve cascade utilization of energy by absorbing the heat of synthesis gas and recovering the heat of CO2 multi-stage compression cooling, generating additional power output.

[0040] A fuel cell is a chemical power generation device that converts the chemical energy of a fuel directly into electrical energy. Solid oxide fuel cells (SOFCs), a type of high-temperature fuel cell, are named because their electrolytes are mostly solid oxides. Their structure primarily consists of a cathode, an anode, and an electrolyte. When oxygen and a gaseous fuel are introduced into the cathode and anode, respectively, the oxygen is catalytically reduced at the cathode to form oxygen ions, which then migrate through the electrolyte to the anode. There, they react with the gaseous fuel to produce water, CO2, and electrons. These electrons are then transported through an external circuit to the cathode, participating in the oxygen reduction reaction, thus forming a closed circuit and generating current.

[0041] Working principle: For the present invention, when in use, first coal and supercritical water enter the gasification chamber 1 to generate synthesis gas. After the synthesis gas passes through the high-temperature heat exchanger 2, it enters the waste heat boiler 4 together with the H2 generated by the water electrolysis device 9, the O2 that has not completely reacted at the cathode of the solid oxide fuel cell 3, and the O2 from the air preheater for mixed combustion; the heat generated by the combustion in the waste heat boiler 4 heats the water to generate supercritical water, which is supplied to the gasification chamber 1; the flue gas generated by the combustion in the waste heat boiler 4 passes through the waste heat recovery device 5 to preheat the water, and then in the condenser 6, the flue gas is cooled and separated to form water, gaseous CO2 and clean flue gas; part of the water separated by the condenser 6 enters the water electrolysis device 9, and the other part enters the waste heat recovery device 5 , after absorbing the waste heat of the flue gas of the waste heat boiler 4, it enters the waste heat boiler 4; the clean flue gas formed by separation by the condenser 6 is discharged into the atmosphere without impurities such as CO2, ash, sulfur, and heavy metals; the gaseous CO2 formed by the separation by the condenser 6 is compressed in two stages by the compressor three 17 and the compressor two 15, and cooled in two stages by the low-temperature heat exchanger two 18 and the low-temperature heat exchanger one 16, and the gaseous CO2 is converted into liquid CO2, which is convenient for storage and transportation. The present invention realizes the efficient and clean utilization of coal, and the CO2 in the exhaust gas can be separated from the CO2 through the condensation process, without providing a large amount of heat for the decarbonization process, thereby reducing the overall energy loss, and avoiding the emission of harmful impurities in the CO2 into the air, thereby avoiding the impact on the environment;

[0042] Secondly, the wind turbine 7 and solar cell 8 power the water electrolysis device 9, which receives a portion of the water from the condenser 6 and decomposes the water into H2 and O2. The H2 enters the waste heat boiler 4, and the O2 enters the cathode of the solid oxide fuel cell 3. In the solid oxide fuel cell 3, oxygen is catalytically reduced at the cathode and reacts with the synthesis gas on the anode side through the electrolyte, directly converting the chemical energy of the synthesis gas into electrical energy and generating water and CO2.

[0043] The turbine 11 is coaxially arranged with the generator body 10. The CO2 at the outlet of the compressor 14 absorbs the cooling heat generated during the compression of the gaseous CO2 through the low-temperature heat exchanger 16 and the low-temperature heat exchanger 2 18, absorbs part of the heat of the synthesis gas through the high-temperature heat exchanger 2, and reaches supercriticality. It expands and performs work in the turbine 11. The turbine 11 rotates and drives the generator body 10 to output electrical energy. The CO2 at the outlet of the turbine 11 passes through the air preheater and transfers heat to the O2, which increases the temperature of the O2 and reduces the temperature of the CO2, facilitating the compression of the CO2 in the compressor 14. The CO2 at the outlet of the compressor 14 then enters the low-temperature heat exchanger 16 and the low-temperature heat exchanger 2 18, and this cycle repeats. The present invention uses clean energy to generate electricity and can generate sufficient electricity for its own use during the power generation process, thereby reducing power loss during the power generation process and improving the power generation efficiency of the coal-fired power plant.

[0044] Finally, the air separator 13 decomposes the air into N2 and O2. The O2 is heated by the heat exchanger body 12 and enters the waste heat boiler 4 to serve as an oxidant in the combustion process. The water electrolysis device 9 produces H2 and O2. The synthesis gas and O2 are respectively introduced into the anode and cathode of the solid oxide fuel cell 3, and react in the solid oxide fuel cell 3 to generate electricity. The gas that has not completely reacted in the solid oxide fuel cell 3 is introduced into the waste heat boiler 4 for combustion. The H2 produced by the water electrolysis device 9 and the O2 produced by the air separator 13 enter the waste heat boiler 4 as supplementary fuel and oxidant.

Claims

1. A three-cycle power generation system integrating fuel cells and supercritical carbon dioxide electrolysis, characterized in that: include: A vaporization chamber (1), wherein the outlet of the vaporization chamber (1) is connected to a high-temperature heat exchanger (2), the high-temperature heat exchanger (2) is connected to a solid oxide fuel cell (3), the solid oxide fuel cell (3) is connected to a waste heat boiler (4), the waste heat boiler (4) is connected to a waste heat recovery device (5), and the waste heat recovery device (5) is connected to a condenser (6); The condenser (6) is also connected to the waste heat recovery device (5); The condenser (6) is connected to a water electrolysis device (9), a compressor (17) The water electrolysis device (9) is connected to the solid oxide fuel cell (3); The compressor 3 (17) is connected to the low-temperature heat exchanger 2 (18), the low-temperature heat exchanger 2 (18) is connected to the compressor 2 (15), and the low-temperature heat exchanger 2 (18) is connected to the high-temperature heat exchanger (2); The second compressor (15) is connected to a first low-temperature heat exchanger (16), and the first low-temperature heat exchanger (16) is connected to the high-temperature heat exchanger (2); The system also includes a CO2 cycle power generation subsystem; The CO2 cycle power generation subsystem includes a generator body (10), a turbine (11) and an air separator (13); The turbine (11) is coaxially arranged with the generator body (10), and the turbine (11) is connected to the high-temperature heat exchanger (2); The generator body (10) is connected to a compressor 1 (14), and the compressor 1 (14) is connected to a low-temperature heat exchanger 1 (16) and a low-temperature heat exchanger 2 (18) respectively; The air separator (13) is connected to a heat exchanger body (12), and the heat exchanger body (12) is connected to a waste heat boiler (4); The high-temperature heat exchanger (2) is connected to the anode of the solid oxide fuel cell (3); The water electrolysis device (9) is connected to the cathode of the solid oxide fuel cell (3).

2. The integrated fuel cell and supercritical carbon dioxide water electrolysis three-cycle power generation system according to claim 1 is characterized in that: The water electrolysis device (9) is powered by a wind generator (7) and a solar cell (8).

3. The water electrolysis three-cycle power generation system integrating fuel cell and supercritical carbon dioxide according to claim 1 is characterized in that: The high-temperature heat exchanger (2), the anode of the solid oxide fuel cell (3), the waste heat boiler (4), the waste heat recovery device (5) and the condenser (6) are connected in series to form a loop.

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