CO2 self-supply supercritical CO2 thermal power plant based on carbon capture and operation method

Abstract

The invention provides a CO2 self-supply supercritical CO2 thermal power plant based on carbon capture and an operation method. The CO2 self-supply supercritical CO2 thermal power plant comprises a fuel combustion module, a supercritical CO2 power circulation module, a carbon capture module and a cooling water circulation module, supercritical CO2 power cycle is used for replacing traditional steam Rankine cycle for power generation, and the power generation efficiency of the system is effectively improved; the CO2 liquid storage tank is introduced into the supercritical CO2 power cycle, so that variable load regulation of a power generation system can be realized, and impurities in a cycle working medium can be effectively discharged; cO2 capture is carried out on flue gas generated in a thermal power plant through an alcohol amine method, carbon emission can be effectively reduced, meanwhile, obtained CO2 is directly used for supercritical CO2 power circulation, CO2 loss caused by leakage, overhauling and the like can be supplemented, self-supply of CO2 of a system is effectively achieved, the cost of purchasing and transporting CO2 of the thermal power plant is reduced, and besides self-utilization, the CO2 recovery rate of the thermal power plant is improved. And redundant CO2 can be conveyed to other industries needing CO2 to participate in the whole carbon market transaction, so that the revenue capacity of the power plant is improved.

Description

Technical Field

[0001] The present invention relates to the fields of carbon capture and supercritical CO2 thermal power generation, and in particular to a CO2 self-supply supercritical CO2 thermal power plant based on carbon capture and an operation method thereof. Background Art

[0002] At present, environmental issues and carbon emission reduction issues have received more and more attention. The goals of carbon peak and carbon neutrality are constantly pushing society towards more energy-saving, environmental protection and carbon reduction. Although the proportion of new energy power generation is increasing, the main source of electricity in society is still thermal power generation. A large amount of CO2 is emitted during thermal power generation, and its capture and utilization is a hot topic of current concern.

[0003] Among the existing disclosed technical solutions, researchers have studied carbon capture in thermal power plants. For example, invention patent CN108679682A discloses a system for recovering waste heat from the dry CO2 capture process in thermal power plants and using it for heating. The system combines low-temperature dry CO2 capture technology and absorption heat exchange technology to recover waste heat from the carbon capture process, while achieving power generation, CO2 capture and centralized heating. Invention patent CN109876590A discloses a thermal power plant using LNG cold energy carbon capture system, combining LNG cold energy utilization with CO2 capture from flue gas emissions of fossil fuel thermal power plants to solve the problem of LNG cold energy waste and CO2 pollution in thermal power plants. In addition, invention patent CN116146296A provides a thermal power plant decarbonization energy storage coupling system, which captures CO2 emitted by thermal power plants for secondary use, and produces carbon monoxide and hydrogen at low cost through solid oxide electrolysis cells, which not only reduces carbon emissions, but also increases the income of generator sets.

[0004] In the existing technical solutions, various methods are adopted to capture and further utilize the CO2 discharged from thermal power plants, which not only reduces carbon emissions but also improves system benefits and energy utilization. However, the thermal power generation in the system still adopts steam Rankine cycle power generation, which has low system efficiency, and the captured CO2 is either directly stored, which increases the storage cost of CO2, or enters other auxiliary systems for utilization, which increases the cost of additional components. Summary of the invention

[0005] The present invention provides a CO2 self-supply supercritical CO2 thermal power plant based on carbon capture, which utilizes a supercritical CO2 power cycle to generate electricity, thereby improving the power generation efficiency of the system. At the same time, the CO2 of the thermal power plant is captured for supercritical CO2 power cycle power generation, thereby achieving self-supply of the system power generation cycle working fluid, reducing carbon emissions, eliminating the storage and transportation costs of CO2 and additional component costs, increasing system revenue, and improving the system energy utilization rate.

[0006] In order to realize the above-mentioned technical features, the purpose of the present invention is achieved as follows: a CO2 self-supply supercritical CO2 thermal power plant based on carbon capture, comprising a fuel combustion module for burning fuel and providing thermal energy; the fuel combustion module is connected to a supercritical CO2 power circulation module; the fuel combustion module and the supercritical CO2 power circulation module are simultaneously connected to a carbon capture module; the supercritical CO2 power circulation module is connected to a cooling water circulation module.

[0007] The fuel combustion module includes a raw coal bunker, the outlet of the raw coal bunker is connected to a coal feeder, the outlet of the coal feeder is connected to a coal mill, the outlet of the coal mill is connected to a burner, the burner is arranged on the side of the boiler furnace, and a heat exchange vertical pipe is arranged inside the boiler furnace; the air outlet of the blower is connected to an air preheater installed on the vertical flue, and the outlet of the air preheater is connected to the coal mill and the burner at the same time.

[0008] The supercritical CO2 power cycle module includes a low-temperature superheater connected to the outlet of the heat exchange riser, the low-temperature superheater is installed on the vertical flue, the other end of the low-temperature superheater is connected to the high-temperature superheater, the high-temperature superheater is arranged on the horizontal flue, the high-temperature superheater is connected to the high-pressure turbine through a first valve, the other end of the high-pressure turbine is connected to the low-temperature reheater, the low-temperature reheater is installed on the vertical flue, the low-temperature reheater is connected to the high-temperature reheater installed on the horizontal flue, the high-temperature reheater is connected to the low-pressure turbine, the low-pressure turbine is connected to the high-temperature reheater, the low-temperature reheater and the first cooler in sequence, the first cooler is connected to the first compressor through a first three-way valve, a second valve and a check valve; The outlet of the first compressor is connected to the low-temperature regenerator and the economizer installed on the vertical flue through the second three-way valve. The low-temperature regenerator and the economizer are connected to the high-temperature regenerator through the third three-way valve, and the high-temperature regenerator is connected to the heat exchange vertical pipe.

[0009] The first three-way valve is connected to the first throttle valve through the third valve, and the first throttle valve is connected to the CO2 liquid storage tank; the bottom of the CO2 liquid storage tank is connected to the first compressor through a CO2 pump, an air vaporizer and a valve, and a ninth valve is installed on the top of the CO2 liquid storage tank.

[0010] The carbon capture module includes a flue gas baffle, which is arranged inside the vertical flue and below the low-temperature reheater and the low-temperature superheater. The low-temperature reheater and the low-temperature superheater are installed side by side. When the flue gas passes through the low-temperature reheater and the low-temperature superheater, the flue gas flow passing through the low-temperature reheater and the low-temperature superheater is regulated by the flue gas baffle; the end of the vertical flue is sequentially provided with a denitrification device, an electrostatic precipitator, a desulfurization device and an induced draft fan; the outlet of the induced draft fan is connected to the chimney through a fifth valve for flue gas discharge or carbon capture.

[0011] The outlet of the induced draft fan is connected to the first heat exchanger and the second heat exchanger in sequence through the sixth valve. The second heat exchanger is connected to the absorption tower. The absorption tower stores amine liquid inside, and allows the flue gas after heat release to enter the absorption tower to react with the lean amine liquid to remove CO2. After that, the flue gas is discharged from the absorption tower. The heat of the flue gas before CO2 removal is absorbed in the second heat exchanger, and then sent to the chimney to be discharged into the environment. The absorption tower is connected to the third heat exchanger through a rich liquid pump, the outlet of the third heat exchanger is connected to the decomposition tower, the decomposition tower is connected to the third heat exchanger through a lean liquid pump, and the third heat exchanger is connected to the absorption tower through a lean liquid cooler.

[0012] The bottom of the analysis tower is connected to the first heat exchanger through an amine solution pump, the first heat exchanger is connected to the oil burner, and the oil burner is connected to the analysis tower.

[0013] A separator is connected to the top of the analysis tower, and the gas is separated by the separator to obtain pure CO2, while the water vapor returns to the analysis tower to heat the rich amine liquid; the separator outlet is connected to the second compressor, and the second compressor outlet is connected to the second cooler. The outlet of the second cooler is divided into two streams, one of which is connected to the third compressor through the seventh valve, and the other is connected to the CO2 liquid storage tank through the eighth valve and the second throttle valve for supercritical CO2 power cycle.

[0014] The cooling water circulation module includes a cooling water pump, which is arranged inside the cooling tower and is used to pump the cooling water in the cooling tower into the first cooler and the second cooler respectively to cool the CO2 therein, and then return to the cooling tower.

[0015] A method for operating a supercritical CO2 thermal power plant with self-supply of CO2 based on carbon capture, comprising: Fuel combustion process: used to burn fuel and generate heat for heating CO2; Supercritical CO2 power cycle process: Use supercritical CO2 power cycle to generate electricity, and introduce CO2 liquid storage tanks into the supercritical CO2 power cycle to achieve variable load regulation of the power generation system and effectively discharge impurities in the circulating working fluid; Carbon capture process: The amine method is used to capture CO2 from flue gas generated in thermal power plants to reduce carbon emissions. At the same time, the obtained CO2 is directly used in the supercritical CO2 power cycle to supplement the CO2 loss caused by leakage and maintenance, effectively realizing the self-supply of CO2 in the system, and the excess CO2 is transported to industries that need CO2 to participate in the entire carbon market transaction; Cooling water circulation process: used to provide the cooling water required for operation during the operation process.

[0016] The fuel combustion process specifically includes: The raw coal in the raw coal bin enters the coal mill through the coal feeder and is ground into coal powder; the blower sends the air to the air preheater installed on the vertical flue for preheating. The preheated air is divided into two streams, one stream enters the coal mill to dry the coal powder, and then the hot air carries the ground coal powder into the burner for combustion, and the other stream directly enters the burner for combustion assistance; the combustion of the fuel generates a large amount of heat in the boiler furnace, and the heat is taken away by the CO2 in the heat exchange vertical pipe.

[0017] The supercritical CO2 power cycle process specifically includes: The CO2 in the heat exchange vertical pipe absorbs a large amount of heat generated in the boiler furnace during the fuel combustion process. The CO2 after absorbing heat passes through the low-temperature superheater installed on the vertical flue and the high-temperature superheater installed on the horizontal flue in turn to continue absorbing heat and become superheated CO2. The superheated CO2 enters the high-pressure turbine through the first valve to expand and do work. The CO2 after doing work passes through the low-temperature reheater installed on the vertical flue and the high-temperature reheater installed on the horizontal flue in turn to absorb heat, and then enters the low-pressure turbine to expand and do work again. The CO2 after doing work passes through the high-temperature regenerator, the low-temperature regenerator and the first cooler in turn to release heat. The CO2 after releasing heat enters the first compressor through the first three-way valve, the second valve and the check valve for compression; The compressed CO2 is divided into two streams. One stream enters the economizer installed on the vertical flue through the second three-way valve to absorb heat. The CO2 after absorbing heat directly enters the high-temperature regenerator through the third three-way valve to absorb heat again. The other stream enters the low-temperature regenerator through the second three-way valve to absorb heat. After that, it is mixed with the CO2 from the economizer through the third three-way valve and enters the high-temperature regenerator to absorb the heat of the CO2 at the outlet of the low-pressure turbine. The CO2 after absorbing heat enters the heat exchange vertical pipe to absorb the heat in the boiler furnace again. During stable operation, the third valve and the fourth valve are closed; during variable operating conditions, when the load decreases, the third valve is opened, and the circulating CO2 enters the first throttle valve through the third valve for throttling, and is then stored in the CO2 liquid storage tank; When the load increases, the fourth valve opens, and the CO2 stored in the CO2 liquid storage tank enters the CO2 pump for pressurization. The pressurized CO2 is gasified in the wind gasifier, and then enters the first compressor through the fourth valve for compression. At the same time, the CO2 liquid storage tank not only stores CO2 to adjust the system load, but also discharges impurities in the working fluid through the liquefaction of CO2. The impurities are discharged from the CO2 liquid storage tank through the ninth valve.

[0018] The carbon capture process specifically includes: After the fuel is burned, hot flue gas is formed in the boiler furnace. The hot flue gas flows along the horizontal flue and vertical flue of the boiler, and releases heat through the high-temperature superheater, high-temperature reheater, low-temperature reheater, low-temperature superheater, economizer and air preheater in turn. The low-temperature reheater and low-temperature superheater are installed side by side. When the flue gas passes through the low-temperature reheater and low-temperature superheater, the flue gas flow through the low-temperature reheater and low-temperature superheater is adjusted by the flue gas damper; the flue gas after heat release enters the denitrification equipment for denitrification, and then enters the electrostatic precipitator to remove dust in the flue gas, and then enters the desulfurization equipment for desulfurization, and then is sent out through the induced draft fan; the flue gas passing through the induced draft fan is passed through the fifth valve The flue gas is directly sent to the chimney and discharged into the environment through the door. It can also be used for carbon capture. The flue gas passes through the first heat exchanger and the second heat exchanger in sequence through the sixth valve to release heat. The flue gas after heat release enters the absorption tower to react with the lean amine liquid to remove CO2. Then the flue gas is discharged from the absorption tower and enters the second heat exchanger to absorb the heat of the flue gas before removing CO2. Then it is sent to the chimney and discharged into the environment. The lean amine liquid after absorbing CO2 in the absorption tower is converted into rich amine liquid. The rich amine liquid is pumped into the third heat exchanger through the rich liquid pump to absorb the heat of the lean amine liquid. Then it enters the analysis tower to contact with the water vapor of the amine solution for thermal analysis. CO2 is generated during the analysis process, and the rich amine liquid is converted into lean amine liquid at the same time. The lean amine liquid flowing out of the analysis tower is pumped into the third heat exchanger by the lean liquid pump to release heat, and then enters the lean liquid cooler to release heat again. The lean amine liquid after heat release enters the absorption tower to react with the flue gas to absorb the CO2 therein; The amine solution produced in the analysis tower is pumped into the first heat exchanger by the amine solution pump to absorb the heat of the flue gas, and then absorbs heat again through the oil burner. After absorbing sufficient heat, amine solution water vapor is obtained, and then enters the analysis tower to react with the rich amine liquid flowing into it to precipitate CO2; The gas precipitated in the analysis tower may contain water vapor, which is separated by a separator to obtain pure CO2, and the water vapor returns to the analysis tower to heat the rich amine liquid. The CO2 at the separator outlet enters the second compressor for compression, and the pressurized CO2 enters the second cooler for cooling, and then is divided into two streams as needed. One stream enters the third compressor through the seventh valve for compression again, and then is used for CO2 storage and transportation, and the other stream enters the second throttle valve through the eighth valve for throttling. The throttled CO2 flows into the CO2 liquid storage tank for storage and is used for supercritical CO2 power cycle.

[0019] The cooling water circulation process specifically includes: The cooling water pump pumps the cooling water in the cooling tower into the first cooler and the second cooler respectively to cool the CO2 therein, and then returns to the cooling tower.

[0020] During the supercritical CO2 power cycle, the CO2 at the outlet of the first cooler controls the flow of the branch through the second valve and the third valve, and the third valve controls the opening and closing of the branch flowing through the CO2 liquid storage tank; the flue gas at the outlet of the induced draft fan controls the flow of the branch through the fifth valve and the sixth valve; the CO2 at the outlet of the second cooler controls the flow of the branch through the seventh valve and the eighth valve; the check valve controls the CO2 in the flow path to flow in one direction only, and after flowing out from the outlet of the wind vaporizer through the fourth valve, it only flows into the first compressor, and will not flow into the first cooler or the first throttle valve through the check valve.

[0021] The fuel combustion process and the supercritical CO2 power cycle process exchange energy through the heat exchange riser; the hot flue gas formed in the boiler furnace carries a large amount of heat, and in the process of the flue gas entering the carbon capture module, it exchanges energy with the high-temperature superheater, high-temperature reheater, low-temperature reheater, low-temperature superheater, economizer and air preheater installed in the horizontal flue and the vertical flue; in the carbon capture module, the heat of the flue gas is further recovered through the first heat exchanger and the second heat exchanger, and the temperature of the flue gas entering the absorption tower is reduced to improve the chemical reaction efficiency of carbon capture in the absorption tower; the supercritical CO2 power cycle process exchanges energy with the cooling water cycle through the first cooler and the second cooler to complete the cooling of CO2 in the cycle.

[0022] Beneficial effects of the present invention: 1. The present invention utilizes supercritical CO2 power cycle to generate electricity, replacing the traditional steam Rankine cycle power generation, effectively improving the energy utilization rate of the system.

[0023] 2. The present invention introduces a CO2 liquid storage tank into the supercritical CO2 power cycle, which can not only quickly realize the variable load regulation of the power generation system, but also effectively discharge impurities in the circulating working fluid.

[0024] 3. The method of CO2 self-supply for supercritical CO2 thermal power plants proposed in the present invention further processes the flue gas generated by the power plant, and directly uses the obtained CO2 in its own power generation cycle, effectively realizing the self-supply of CO2 in the system, while effectively reducing the cost of purchasing and transporting CO2 for the thermal power plant.

[0025] 4. The present invention captures CO2 in flue gas and can effectively reduce carbon emissions, which is in line with the national dual carbon policy. At the same time, the collected CO2 can be transported to other industries that need CO2, or sealed for subsequent use, and can participate in the entire carbon market transaction, thereby increasing the revenue capacity of the power plant.

[0026] 5. The present invention introduces a CO2 liquid storage tank into the supercritical CO2 power cycle, which can not only realize variable load regulation of the power generation system, but also effectively discharge impurities in the circulating working fluid.

[0027] 6. The present invention utilizes the alcohol amine method to capture CO2 from the flue gas generated in the thermal power plant, and directly uses the obtained CO2 in the supercritical CO2 power cycle to supplement the CO2 loss caused by leakage, maintenance, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0029] Figure 1 It is the overall flow chart of the present invention.

[0030] Figure 2 The present invention Figure 1 An enlarged view of the fuel combustion module.

[0031] Figure 3 For the present invention Figure 1 A magnified view of the location of the carbon capture module.

[0032] In the figure: 1-raw coal bunker, 2-coal feeder, 3-pulverizer, 4-burner, 5-heat exchange vertical pipe, 6-boiler furnace, 7-low temperature superheater, 8-high temperature superheater, 9-first valve, 10-high pressure turbine, 11-low temperature reheater, 12-high temperature reheater, 13-low pressure turbine, 14-high temperature reheater, 15-low temperature reheater, 16-first cooler, 17-first three-way valve, 18-second valve, 19-check valve, 20-first compressor, 21-second three-way valve, 22-economizer, 23-third three-way valve, 24-blower, 25-air preheater, 26-third valve, 27-first throttle valve, 28-CO2 liquid storage tank, 29-CO2 pump , 30-air gasifier, 31-fourth valve, 32-smoke damper, 33-desulfurization equipment, 34-electrostatic precipitator, 35-desulfurization equipment, 36-induced draft fan, 37-fifth valve, 38-sixth valve, 39-first heat exchanger, 40-second heat exchanger, 41-absorption tower, 42-rich liquid pump, 43-third heat exchanger, 44-analysis tower, 45-lean liquid pump, 46-lean liquid cooler, 47-amine solution pump, 48-oil furnace, 49-separator, 50-second compressor, 51-second cooler, 52-seventh valve, 53-third compressor, 54-eighth valve, 55-second throttle valve, 56-ninth valve, 57-cooling water pump, 58-cooling tower. DETAILED DESCRIPTION

[0033] In order to more clearly illustrate the technical solutions of the embodiments of this specification, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of this specification. For ordinary technicians in this field, this specification can also be applied to other similar scenarios based on these drawings without creative work. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation.

[0034] Embodiment 1: See also Figure 1-3 , a CO2 self-supply supercritical CO2 thermal power plant based on carbon capture, including a fuel combustion module for fuel combustion and providing heat energy; the fuel combustion module is connected to a supercritical CO2 power cycle module; the fuel combustion module and the supercritical CO2 power cycle module are simultaneously connected to a carbon capture module; the supercritical CO2 power cycle module is connected to a cooling water cycle module. By adopting the above-mentioned power plant, the supercritical CO2 power cycle is used to generate electricity, thereby improving the power generation efficiency of the system. At the same time, the CO2 of the thermal power plant is captured for supercritical CO2 power cycle power generation, thereby achieving self-supply of the system power generation cycle working fluid, reducing carbon emissions, eliminating the storage and transportation costs of CO2 and the cost of additional components, increasing system revenue, and improving system energy utilization.

[0035] Embodiment 2: Furthermore, the fuel combustion module includes a raw coal bin 1, the outlet of the raw coal bin 1 is connected to a coal feeder 2, the outlet of the coal feeder 2 is connected to a coal mill 3, the outlet of the coal mill 3 is connected to a burner 4, the burner 4 is arranged on the side of a boiler furnace 6, and a heat exchange vertical pipe 5 is arranged inside the boiler furnace 6; it also includes a blower 24, the air outlet of the blower 24 is connected to an air preheater 25 installed on a vertical flue, and the outlet of the air preheater 25 is connected to both the coal mill 3 and the burner 4.

[0036] The above-mentioned fuel combustion module can be used to provide heat energy in the power generation process. In the specific working process, the raw coal in the raw coal bin 1 enters the coal mill 3 through the coal feeder 2 and is ground into coal powder; the blower 24 sends air to the air preheater 25 installed on the vertical flue for preheating, and the preheated air is divided into two streams, one enters the coal mill 3 to dry the coal powder, and then the hot air carries the ground coal powder into the burner 4 for combustion, and the other directly enters the burner 4 for combustion support; the combustion of the fuel generates a large amount of heat in the boiler furnace 6, and the heat is taken away by the CO2 in the heat exchange vertical pipe 5.

[0037] Embodiment 3: Furthermore, the supercritical CO2 power cycle module includes a low-temperature superheater 7 connected to the outlet of the heat exchange riser 5, the low-temperature superheater 7 is installed on the vertical flue, the other end of the low-temperature superheater 7 is connected to the high-temperature superheater 8, the high-temperature superheater 8 is arranged on the horizontal flue, the high-temperature superheater 8 is connected to the high-pressure turbine 10 through the first valve 9, the other end of the high-pressure turbine 10 is connected to the low-temperature reheater 11, the low-temperature reheater 11 is installed on the vertical flue, the low-temperature reheater 11 is connected to the high-temperature reheater 12 installed on the horizontal flue, and the high-temperature reheater 12 is connected to the high-pressure turbine 10. The low-pressure turbine 13 is connected, and the low-pressure turbine 13 is connected to the high-temperature regenerator 14, the low-temperature regenerator 15 and the first cooler 16 in sequence. The first cooler 16 is connected to the first compressor 20 through the first three-way valve 17, the second valve 18 and the check valve 19; the outlet of the first compressor 20 is respectively connected to the low-temperature regenerator 15 and the economizer 22 installed on the vertical flue through the second three-way valve 21, and the low-temperature regenerator 15 and the economizer 22 are both connected to the high-temperature regenerator 14 through the third three-way valve 23, and the high-temperature regenerator 14 is connected to the heat exchange vertical pipe 5. The first three-way valve 17 is connected to the first throttle valve 27 through the third valve 26, and the first throttle valve 27 is connected to the CO2 liquid storage tank 28; the bottom of the CO2 liquid storage tank 28 is connected to the first compressor 20 through the CO2 pump 29, the wind gasifier 30 and the valve 31, and the top of the CO2 liquid storage tank 28 is installed with a ninth valve 56.

[0038] The above-mentioned supercritical CO2 power cycle module can realize the circulation of supercritical CO2, and then realize the power generation process. In the specific working process, the CO2 in the heat exchange vertical pipe 5 absorbs a large amount of heat generated in the boiler furnace 6 during the fuel combustion process. The CO2 after absorbing heat passes through the low-temperature superheater 7 installed on the vertical flue and the high-temperature superheater 8 installed on the horizontal flue in turn to continue absorbing heat and become superheated CO2. The superheated CO2 enters the high-pressure turbine 10 through the first valve 9 to expand and do work. The CO2 after doing work passes through the low-temperature reheater 11 installed on the vertical flue and the high-temperature reheater 12 installed on the horizontal flue in turn to absorb heat, and then enters the low-pressure turbine 10. The CO2 expands again to do work, and the CO2 after doing work passes through the high-temperature regenerator 14, the low-temperature regenerator 15 and the first cooler 16 in sequence to release heat. The CO2 after releasing heat enters the first compressor 20 through the first three-way valve 17, the second valve 18 and the check valve 19 for compression; the compressed CO2 is divided into two streams, one of which enters the economizer 22 installed on the vertical flue through the second three-way valve 21 to absorb heat, and the CO2 after absorbing heat directly enters the high-temperature regenerator 14 through the third three-way valve 23 to absorb heat again, and the other stream passes through the second three-way valve 2 1 enters the low-temperature regenerator 15 to absorb heat, then passes through the third three-way valve 23 to mix with the CO2 from the economizer 22, enters the high-temperature regenerator 14 to absorb the heat of the CO2 at the outlet of the low-pressure turbine 13, and the CO2 after absorbing heat enters the heat exchange riser 5 to absorb the heat in the boiler furnace 6 again; during stable operation, the third valve 26 and the fourth valve 31 are closed; during variable operating conditions, when the load decreases, the third valve 26 is opened, and the circulating CO2 enters the first throttle valve 27 through the third valve 26 to throttle , and then stored in the CO2 liquid storage tank 28; when the load increases, the fourth valve 31 opens, and the CO2 stored in the CO2 liquid storage tank 28 enters the CO2 pump 29 for pressurization, and the pressurized CO2 is gasified in the wind gasifier 30, and then enters the first compressor 20 through the fourth valve 31 for compression; at the same time, the CO2 liquid storage tank 28 not only stores CO2 to achieve system load regulation, but also discharges impurities in the working fluid through the liquefaction of CO2, and the impurities are discharged from the CO2 liquid storage tank 28 through the ninth valve 56.

[0039] Embodiment 4: Furthermore, the carbon capture module includes a flue gas baffle 32, which is arranged inside the vertical flue and below the low-temperature reheater 11 and the low-temperature superheater 7. The low-temperature reheater 11 and the low-temperature superheater 7 are installed side by side. When the flue gas passes through the low-temperature reheater 11 and the low-temperature superheater 7, the flue gas flow passing through the low-temperature reheater 11 and the low-temperature superheater 7 is regulated by the flue gas baffle 32; the end of the vertical flue is sequentially provided with a denitrification device 33, an electrostatic precipitator 34, a desulfurization device 35 and an induced draft fan 36; the outlet of the induced draft fan 36 is connected to the chimney through a fifth valve 37 for flue gas discharge or carbon capture. The outlet of the induced draft fan 36 is connected to the first heat exchanger 39 and the second heat exchanger 40 in sequence through the sixth valve 38. The second heat exchanger 40 is connected to the absorption tower 41. The absorption tower 41 stores amine liquid inside, and allows the flue gas after heat release to enter the absorption tower 41 to react with the lean amine liquid to remove CO2. Then the flue gas is discharged from the absorption tower 41. The heat of the flue gas before CO2 removal is absorbed in the second heat exchanger 40, and then sent to the chimney to be discharged into the environment; the absorption tower 41 is connected to the third heat exchanger 43 through the rich liquid pump 42, and the outlet of the third heat exchanger 43 is connected to the desorption tower 44. The desorption tower 44 is connected to the third heat exchanger 43 through the lean liquid pump 45, and the third heat exchanger 43 is connected to the absorption tower 41 through the lean liquid cooler 46. The bottom of the desorption tower 44 is connected to the first heat exchanger 39 through the amine solution pump 47, the first heat exchanger 39 is connected to the oil burner 48, and the oil burner 48 is connected to the desorption tower 44. A separator 49 is connected to the top of the analysis tower 44, and the gas is separated by the separator 49 to obtain pure CO2, while the water vapor returns to the analysis tower 44 to heat the rich amine liquid; the outlet of the separator 49 is connected to the second compressor 50, and the outlet of the second compressor 50 is connected to the second cooler 51. The outlet of the second cooler 51 is divided into two streams, one of which is connected to the third compressor 53 through the seventh valve 52, and the other is connected to the CO2 liquid storage tank 28 through the eighth valve 54 and the second throttle valve 55 for supercritical CO2 power cycle.

[0040] The carbon capture module mentioned above uses the alcohol amine method to capture CO2 from the flue gas generated in the thermal power plant, and the obtained CO2 is directly used in the supercritical CO2 power cycle to supplement the CO2 loss caused by leakage, maintenance, etc. In the specific operation process, hot flue gas is formed in the boiler furnace 6 after the fuel is burned. The hot flue gas flows along the horizontal flue and vertical flue of the boiler, and releases heat through the high-temperature superheater 8, the high-temperature reheater 12, the low-temperature reheater 11, the low-temperature superheater 7, the economizer 22 and the air preheater 25 in sequence, wherein the low-temperature reheater 11 and the low-temperature superheater 7 are installed side by side. When the flue gas passes through the low-temperature reheater 11 and the low-temperature superheater 7, the flue gas baffle 32 adjusts the flue gas flow through the low-temperature reheater 11 and the low-temperature superheater 7; the flue gas after heat release enters the denitrification equipment 33 for denitrification, and then enters the electrostatic precipitator 34 to remove dust in the flue gas, and then enters the desulfurization equipment 35 for desulfurization, and then is sent out through the induced draft fan 36; after the induced draft fan The flue gas of 36 is directly sent to the chimney through the fifth valve 37 to be discharged into the environment, and can also be used for carbon capture. The flue gas passes through the first heat exchanger 39 and the second heat exchanger 40 in sequence through the sixth valve 38 to release heat. The flue gas after heat release enters the absorption tower 41 to react with the lean amine liquid to remove CO2, and then the flue gas is discharged from the absorption tower 41, enters the second heat exchanger 40 to absorb the heat of the flue gas before removing CO2, and then is sent to the chimney to be discharged into the environment; the lean amine liquid after absorbing CO2 in the absorption tower 41 is converted into rich amine liquid, and the rich amine liquid is pumped into the third heat exchanger 43 through the rich liquid pump 42 to absorb the heat of the lean amine liquid, and then enters the analysis tower 44 to contact with the water vapor of the amine solution for thermal analysis, CO2 is generated during the analysis, and the rich amine liquid is converted into lean amine liquid at the same time; The lean amine liquid flowing out of the analysis tower 44 is pumped into the third heat exchanger 43 by the lean liquid pump 45 to release heat, and then enters the lean liquid cooler 46 to release heat again. The lean amine liquid after heat release enters the absorption tower 41 to react with the flue gas to absorb CO2 therein; The amine solution produced in the analysis tower 44 is pumped into the first heat exchanger 39 by the amine solution pump 47 to absorb the heat of the flue gas, and then is absorbed again by the fuel burner 48. After absorbing sufficient heat, the amine solution water vapor is obtained, and then enters the analysis tower 44 to react with the rich amine liquid flowing into it to precipitate CO2; The gas precipitated in the analysis tower 44 may contain water vapor, and the gas is separated by the separator 49 to obtain pure CO2, and the water vapor returns to the analysis tower 44 to heat the rich amine liquid. The CO2 at the outlet of the separator 49 enters the second compressor 50 for compression, and the pressurized CO2 enters the second cooler 51 for cooling, and then is divided into two streams as needed. One stream enters the third compressor 53 through the seventh valve 52 for compression again, and then is used for CO2 storage and transportation, and the other stream enters the second throttle valve 55 through the eighth valve 54 for throttling. The throttled CO2 flows into the CO2 liquid storage tank 28 for storage and is used for supercritical CO2 power cycle.

[0041] Embodiment 5: Further, the cooling water circulation module includes a cooling water pump 57, which is arranged inside the cooling tower 58 and is used to pump the cooling water in the cooling tower 58 into the first cooler 16 and the second cooler 51 respectively to cool the CO2 therein, and then return to the cooling tower 58. The above-mentioned cooling water circulation module can be used to cool the system operation process. In the specific operation process, the cooling water pump 57 pumps the cooling water in the cooling tower 58 into the first cooler 16 and the second cooler 51 respectively to cool the CO2 therein, and then returns to the cooling tower 58.

[0042] Embodiment 6: A method for operating a supercritical CO2 thermal power plant with self-supply of CO2 based on carbon capture, comprising: Fuel combustion process: used to burn fuel and generate heat for heating CO2; Supercritical CO2 power cycle process: Use supercritical CO2 power cycle to generate electricity, and introduce CO2 liquid storage tanks into the supercritical CO2 power cycle to achieve variable load regulation of the power generation system and effectively discharge impurities in the circulating working fluid; Carbon capture process: The amine method is used to capture CO2 from flue gas generated in thermal power plants to reduce carbon emissions. At the same time, the obtained CO2 is directly used in the supercritical CO2 power cycle to supplement the CO2 loss caused by leakage and maintenance, effectively realizing the self-supply of CO2 in the system, and the excess CO2 is transported to industries that need CO2 to participate in the entire carbon market transaction; Cooling water circulation process: used to provide the cooling water required for operation during the operation process.

[0043] The fuel combustion process specifically includes: The raw coal in the raw coal bin 1 enters the coal mill 3 through the coal feeder 2 and is ground into coal powder; the blower 24 sends air to the air preheater 25 installed on the vertical flue for preheating, and the preheated air is divided into two streams, one stream enters the coal mill 3 to dry the coal powder, and then the hot air carries the ground coal powder into the burner 4 for combustion, and the other stream directly enters the burner 4 for combustion assistance; the combustion of the fuel generates a large amount of heat in the boiler furnace 6, and the heat is taken away by the CO2 in the heat exchange vertical pipe 5.

[0044] The supercritical CO2 power cycle process specifically includes: The CO2 in the heat exchange vertical pipe 5 absorbs a large amount of heat generated in the boiler furnace 6 during the fuel combustion process. The CO2 after absorbing heat passes through the low-temperature superheater 7 installed on the vertical flue and the high-temperature superheater 8 installed on the horizontal flue in sequence to continue absorbing heat and become superheated CO2. The superheated CO2 enters the high-pressure turbine 10 through the first valve 9 to expand and do work. The CO2 after doing work passes through the low-temperature reheater 11 installed on the vertical flue and the high-temperature reheater 12 installed on the horizontal flue in sequence to absorb heat, and then enters the low-pressure turbine 13 to expand and do work again. The CO2 after doing work passes through the high-temperature regenerator 14, the low-temperature regenerator 15 and the first cooler 16 in sequence to release heat. The CO2 after releasing heat passes through the first three-way valve 17, the second valve 18 and the check valve 19 to enter the first compressor 20 for compression; The compressed CO2 is divided into two streams, one stream passes through the second three-way valve 21 and enters the economizer 22 installed on the vertical flue to absorb heat. The CO2 after absorbing heat directly enters the high-temperature regenerator 14 through the third three-way valve 23 to absorb heat again. The other stream passes through the second three-way valve 21 and enters the low-temperature regenerator 15 to absorb heat. After that, it passes through the third three-way valve 23 and is mixed with the CO2 from the economizer 22, and then enters the high-temperature regenerator 14 to absorb the heat of the CO2 at the outlet of the low-pressure turbine 13. The CO2 after absorbing heat enters the heat exchange vertical pipe 5 to absorb the heat in the boiler furnace 6 again. During stable operation, the third valve 26 and the fourth valve 31 are closed; during variable operating conditions, when the load decreases, the third valve 26 is opened, and the circulating CO2 enters the first throttle valve 27 through the third valve 26 for throttling, and is then stored in the CO2 liquid storage tank 28; When the load increases, the fourth valve 31 opens, and the CO2 stored in the CO2 liquid storage tank 28 enters the CO2 pump 29 for pressurization. The pressurized CO2 is gasified in the wind gasifier 30, and then enters the first compressor 20 through the fourth valve 31 for compression. At the same time, the CO2 liquid storage tank 28 not only stores CO2 to adjust the system load, but also discharges impurities in the working fluid through the liquefaction of CO2. The impurities are discharged from the CO2 liquid storage tank 28 through the ninth valve 56.

[0045] The carbon capture process specifically includes: After the fuel is burned, hot flue gas is formed in the boiler furnace 6. The hot flue gas flows along the horizontal flue and the vertical flue of the boiler, and releases heat through the high-temperature superheater 8, the high-temperature reheater 12, the low-temperature reheater 11, the low-temperature superheater 7, the economizer 22 and the air preheater 25 in sequence. Among them, the low-temperature reheater 11 and the low-temperature superheater 7 are installed side by side. When the flue gas passes through the low-temperature reheater 11 and the low-temperature superheater 7, the flue gas flow rate passing through the low-temperature reheater 11 and the low-temperature superheater 7 is adjusted by the flue gas damper 32; the flue gas after heat release enters the denitrification equipment 33 for denitrification, and then enters the electrostatic precipitator 34 to remove dust in the flue gas, and then enters the desulfurization equipment 35 for desulfurization, and then is sent out through the induced draft fan 36; the flue gas passing through the induced draft fan 36 The flue gas is directly sent to the chimney through the fifth valve 37 and discharged into the environment. It can also be used for carbon capture. The flue gas passes through the first heat exchanger 39 and the second heat exchanger 40 in sequence through the sixth valve 38 to release heat. The flue gas after heat release enters the absorption tower 41 to react with the lean amine liquid to remove CO2. Then the flue gas is discharged from the absorption tower 41 and enters the second heat exchanger 40 to absorb the heat of the flue gas before removing CO2. Then it is sent to the chimney and discharged into the environment. The lean amine liquid after absorbing CO2 in the absorption tower 41 is converted into rich amine liquid. The rich amine liquid is pumped into the third heat exchanger 43 through the rich liquid pump 42 to absorb the heat of the lean amine liquid. Then it enters the analysis tower 44 to contact with the water vapor of the amine solution for thermal analysis. CO2 is generated during the analysis process, and the rich amine liquid is converted into lean amine liquid. The lean amine liquid flowing out of the analysis tower 44 is pumped into the third heat exchanger 43 by the lean liquid pump 45 to release heat, and then enters the lean liquid cooler 46 to release heat again. The lean amine liquid after heat release enters the absorption tower 41 to react with the flue gas to absorb CO2 therein; The amine solution produced in the analysis tower 44 is pumped into the first heat exchanger 39 by the amine solution pump 47 to absorb the heat of the flue gas, and then is absorbed again by the fuel burner 48. After absorbing sufficient heat, the amine solution water vapor is obtained, and then enters the analysis tower 44 to react with the rich amine liquid flowing into it to precipitate CO2; The gas precipitated in the analysis tower 44 may contain water vapor, and the gas is separated by the separator 49 to obtain pure CO2, and the water vapor returns to the analysis tower 44 to heat the rich amine liquid. The CO2 at the outlet of the separator 49 enters the second compressor 50 for compression, and the pressurized CO2 enters the second cooler 51 for cooling, and then is divided into two streams as needed. One stream enters the third compressor 53 through the seventh valve 52 for compression again, and then is used for CO2 storage and transportation, and the other stream enters the second throttle valve 55 through the eighth valve 54 for throttling. The throttled CO2 flows into the CO2 liquid storage tank 28 for storage and is used for supercritical CO2 power cycle.

[0046] The cooling water circulation process specifically includes: The cooling water pump 57 pumps the cooling water in the cooling tower 58 into the first cooler 16 and the second cooler 51 respectively to cool the CO 2 therein, and then returns to the cooling tower 58 .

[0047] During the supercritical CO2 power cycle, the CO2 at the outlet of the first cooler 16 controls the flow of the branch through the second valve 18 and the third valve 26, and the third valve 26 controls the opening and closing of the branch flowing through the CO2 liquid storage tank 28; the flue gas at the outlet of the induced draft fan 36 controls the flow of the branch through the fifth valve 37 and the sixth valve 38; the CO2 at the outlet of the second cooler 51 controls the flow of the branch through the seventh valve 52 and the eighth valve 54; the check valve 19 controls the CO2 in the flow path to flow only in one direction, and after flowing out from the outlet of the wind gasifier 30 through the fourth valve 31, it only flows into the first compressor 20, and will not flow into the first cooler 16 or the first throttle valve 27 through the check valve 19.

[0048] The fuel combustion process and the supercritical CO2 power cycle process exchange energy through the heat exchange riser 5; the hot flue gas formed in the boiler furnace 6 carries a large amount of heat. In the process of the flue gas entering the carbon capture module, it exchanges energy with the high-temperature superheater 8, high-temperature reheater 12, low-temperature reheater 11, low-temperature superheater 7, economizer 22 and air preheater 25 installed in the horizontal flue and the vertical flue; in the carbon capture module, the heat of the flue gas is further recovered through the first heat exchanger 39 and the second heat exchanger 40, and the flue gas temperature entering the absorption tower 41 is reduced to improve the chemical reaction efficiency of carbon capture in the absorption tower; the supercritical CO2 power cycle process exchanges energy with the cooling water cycle through the first cooler 16 and the second cooler 51 to complete the cooling of CO2 in the cycle.

[0049] Finally, it should be understood that the embodiments described in this specification are only used to illustrate the principles of the embodiments of this specification. Other variations may also fall within the scope of this specification. Therefore, as an example and not a limitation, alternative configurations of the embodiments of this specification may be considered consistent with the teachings of this specification. Accordingly, the embodiments of this specification are not limited to the embodiments explicitly introduced and described in this specification.

Claims

1. A CO2 self-supply supercritical CO2 thermal power plant based on carbon capture, characterized in that: It includes a fuel combustion module for burning fuel and providing heat energy; the fuel combustion module is connected to a supercritical CO2 power circulation module; the fuel combustion module and the supercritical CO2 power circulation module are simultaneously connected to a carbon capture module; the supercritical CO2 power circulation module is connected to a cooling water circulation module.

2. A CO2 self-supply supercritical CO2 thermal power plant based on carbon capture according to claim 1, characterized in that: The fuel combustion module comprises a raw coal bin (1), the outlet of the raw coal bin (1) is connected to a coal feeder (2), the outlet of the coal feeder (2) is connected to a coal mill (3), the outlet of the coal mill (3) is connected to a burner (4), the burner (4) is arranged on the side of a boiler furnace (6), and a heat exchange vertical pipe (5) is arranged inside the boiler furnace (6); the air outlet of the air blower (24) is connected to an air preheater (25) installed on a vertical flue, and the outlet of the air preheater (25) is connected to both the coal mill (3) and the burner (4).

3. A CO2 self-supply supercritical CO2 thermal power plant based on carbon capture according to claim 2, characterized in that: The supercritical CO2 power cycle module comprises a low-temperature superheater (7) connected to the outlet of the heat exchange riser (5), the low-temperature superheater (7) being installed on the vertical flue, the other end of the low-temperature superheater (7) being connected to a high-temperature superheater (8), the high-temperature superheater (8) being arranged on the horizontal flue, the high-temperature superheater (8) being connected to a high-pressure turbine (10) via a first valve (9), the other end of the high-pressure turbine (10) being connected to a low-temperature reheater (11), the low-temperature reheater (12) being connected to the high-pressure turbine (10) via a first valve (9). 1) Installed on a vertical flue, a low-temperature reheater (11) is connected to a high-temperature reheater (12) installed on a horizontal flue, the high-temperature reheater (12) is connected to a low-pressure turbine (13), the low-pressure turbine (13) is connected in sequence to a high-temperature regenerator (14), a low-temperature regenerator (15) and a first cooler (16), the first cooler (16) is connected to a first compressor (20) via a first three-way valve (17), a second valve (18) and a check valve (19); The outlet of the first compressor (20) is respectively connected to a low-temperature regenerator (15) and an economizer (22) installed on the vertical flue through a second three-way valve (21); the low-temperature regenerator (15) and the economizer (22) are both connected to a high-temperature regenerator (14) through a third three-way valve (23); and the high-temperature regenerator (14) is connected to a heat exchange vertical pipe (5).

4. A CO2 self-supply supercritical CO2 thermal power plant based on carbon capture according to claim 3, characterized in that: The first three-way valve (17) is connected to the first throttle valve (27) via the third valve (26), and the first throttle valve (27) is connected to the CO2 liquid storage tank (28); the bottom of the CO2 liquid storage tank (28) is connected to the first compressor (20) via the CO2 pump (29), the air vaporizer (30) and the valve (31), and the top of the CO2 liquid storage tank (28) is installed with a ninth valve (56).

5. A CO2 self-supply supercritical CO2 thermal power plant based on carbon capture according to claim 4, characterized in that: The carbon capture module comprises a flue gas damper (32), which is arranged inside a vertical flue and below a low-temperature reheater (11) and a low-temperature superheater (7). The low-temperature reheater (11) and the low-temperature superheater (7) are installed side by side. When the flue gas passes through the low-temperature reheater (11) and the low-temperature superheater (7), the flue gas flow rate passing through the low-temperature reheater (11) and the low-temperature superheater (7) is regulated by the flue gas damper (32); a denitration device (33), an electrostatic precipitator (34), a desulfurization device (35) and an induced draft fan (36) are arranged in sequence at the end of the vertical flue; the outlet of the induced draft fan (36) is connected to a chimney through a fifth valve (37) to discharge the flue gas or capture carbon.

6. A CO2 self-supply supercritical CO2 thermal power plant based on carbon capture according to claim 5, characterized in that: The outlet of the induced draft fan (36) is connected to the first heat exchanger (39) and the second heat exchanger (40) in sequence through the sixth valve (38); the second heat exchanger (40) is connected to the absorption tower (41); the absorption tower (41) stores amine liquid inside, and allows the flue gas after heat release to enter the absorption tower (41) to react with the lean amine liquid to remove CO2; then the flue gas is discharged from the absorption tower (41); the heat of the flue gas before CO2 removal is absorbed in the second heat exchanger (40), and then sent to the chimney for discharge into the environment; The absorption tower (41) is connected to the third heat exchanger (43) via a rich liquid pump (42); the outlet of the third heat exchanger (43) is connected to the decomposition tower (44); the decomposition tower (44) is connected to the third heat exchanger (43) via a lean liquid pump (45); and the third heat exchanger (43) is connected to the absorption tower (41) via a lean liquid cooler (46).

7. A CO2 self-supply supercritical CO2 thermal power plant based on carbon capture according to claim 6, characterized in that: The bottom of the analysis tower (44) is connected to the first heat exchanger (39) via an amine solution pump (47), the first heat exchanger (39) is connected to the oil burner (48), and the oil burner (48) is connected to the analysis tower (44).

8. A CO2 self-supply supercritical CO2 thermal power plant based on carbon capture according to claim 7, characterized in that: The top of the analysis tower (44) is connected to a separator (49), and the gas is separated by the separator (49) to obtain pure CO2, while the water vapor returns to the analysis tower (44) to heat the rich amine liquid; the outlet of the separator (49) is connected to the second compressor (50), and the outlet of the second compressor (50) is connected to the second cooler (51), and the outlet of the second cooler (51) is divided into two streams, one of which is connected to the third compressor (53) through the seventh valve (52), and the other is connected to the CO2 liquid storage tank (28) through the eighth valve (54) and the second throttle valve (55), for supercritical CO2 power cycle.

9. A CO2 self-supply supercritical CO2 thermal power plant based on carbon capture according to claim 5, characterized in that: The cooling water circulation module comprises a cooling water pump (57), which is arranged inside a cooling tower (58) and is used to pump cooling water in the cooling tower (58) into a first cooler (16) and a second cooler (51) respectively to cool the CO2 therein, and then returns the cooling water to the cooling tower (58).

10. The method for operating a supercritical CO2 thermal power plant with self-supply of CO2 based on carbon capture as claimed in claim 9, characterized in that: include: Fuel combustion process: used to burn fuel and generate heat for heating CO2; Supercritical CO2 power cycle process: Use supercritical CO2 power cycle to generate electricity, and introduce CO2 liquid storage tanks into the supercritical CO2 power cycle to achieve variable load regulation of the power generation system and effectively discharge impurities in the circulating working fluid; Carbon capture process: The amine method is used to capture CO2 from flue gas generated in thermal power plants to reduce carbon emissions. At the same time, the obtained CO2 is directly used in the supercritical CO2 power cycle to supplement the CO2 loss caused by leakage and maintenance, effectively realizing the self-supply of CO2 in the system, and the excess CO2 is transported to industries that need CO2 to participate in the entire carbon market transaction; Cooling water circulation process: used to provide the cooling water required for operation during the operation process.

11. The method for operating a supercritical CO2 thermal power plant with self-supply of CO2 based on carbon capture according to claim 10, characterized in that: The fuel combustion process specifically includes: The raw coal in the raw coal bin (1) enters the coal mill (3) through the coal feeder (2) and is ground into coal powder. The blower (24) sends air to the air preheater (25) installed on the vertical flue for preheating. The preheated air is divided into two streams. One stream enters the coal mill (3) to dry the coal powder. Then, the hot air carries the ground coal powder into the burner (4) for combustion. The other stream directly enters the burner (4) for combustion assistance. The combustion of the fuel generates a large amount of heat in the boiler furnace (6), and the heat is taken away by the CO2 in the heat exchange vertical pipe (5).

12. The method for operating a supercritical CO2 thermal power plant with self-supply of CO2 based on carbon capture according to claim 10, characterized in that: The supercritical CO2 power cycle process specifically includes: The CO2 in the heat exchange vertical pipe (5) absorbs a large amount of heat generated in the boiler furnace (6) during the combustion of the fuel. The CO2 after absorbing heat passes through the low-temperature superheater (7) installed on the vertical flue and the high-temperature superheater (8) installed on the horizontal flue in turn to continue absorbing heat and become superheated CO2. The superheated CO2 enters the high-pressure turbine (10) through the first valve (9) to expand and do work. The CO2 after doing work passes through the low-temperature reheater (11) installed on the vertical flue and the high-temperature reheater (12) installed on the horizontal flue in turn to absorb heat, and then enters the low-pressure turbine (13) to expand and do work again. The CO2 after doing work passes through the high-temperature reheater (14), the low-temperature reheater (15) and the first cooler (16) in turn to release heat. The CO2 after releasing heat passes through the first three-way valve (17), the second valve (18) and the check valve (19) to enter the first compressor (20) for compression; The compressed CO2 is divided into two streams, one stream passes through the second three-way valve (21) and enters the economizer (22) installed on the vertical flue to absorb heat. The CO2 that has absorbed heat directly enters the high-temperature regenerator (14) through the third three-way valve (23) to absorb heat again. The other stream passes through the second three-way valve (21) and enters the low-temperature regenerator (15) to absorb heat. After that, it passes through the third three-way valve (23) and is mixed with the CO2 from the economizer (22). It then enters the high-temperature regenerator (14) to absorb heat from the CO2 at the outlet of the low-pressure turbine (13). The CO2 that has absorbed heat enters the heat exchange vertical pipe (5) to absorb heat from the boiler furnace (6) again. During stable operation, the third valve (26) and the fourth valve (31) are closed; during variable operating conditions, when the load decreases, the third valve (26) is opened, and the circulating CO2 enters the first throttle valve (27) through the third valve (26) for throttling, and is then stored in the CO2 liquid storage tank (28); When the load increases, the fourth valve (31) opens, and the CO2 stored in the CO2 liquid storage tank (28) enters the CO2 pump (29) for pressurization. The pressurized CO2 is gasified in the wind gasifier (30), and then enters the first compressor (20) for compression through the fourth valve (31). At the same time, the CO2 liquid storage tank (28) not only stores CO2 to adjust the system load, but also discharges impurities in the working fluid through the liquefaction of CO2. The impurities are discharged from the CO2 liquid storage tank (28) through the ninth valve (56).

13. The method for operating a supercritical CO2 thermal power plant with self-supply of CO2 based on carbon capture according to claim 10, characterized in that: The carbon capture process specifically includes: After the fuel is burned, hot flue gas is formed in the boiler furnace (6). The hot flue gas flows along the horizontal flue and the vertical flue of the boiler, and releases heat by passing through the high-temperature superheater (8), the high-temperature reheater (12), the low-temperature reheater (11), the low-temperature superheater (7), the economizer (22) and the air preheater (25) in sequence. The low-temperature reheater (11) and the low-temperature superheater (7) are installed side by side. When the flue gas passes through the low-temperature reheater (11) and the low-temperature superheater (7), the flue gas flow rate passing through the low-temperature reheater (11) and the low-temperature superheater (7) is adjusted by the flue gas damper (32); the flue gas after releasing heat enters the denitration device (33) for denitration, then enters the electrostatic precipitator (34) to remove dust in the flue gas, then enters the desulfurization device (35) for desulfurization, and then is sent out through the induced draft fan (36); after passing through the induced draft fan (36), the flue gas is discharged. The flue gas from the fan (36) is directly sent to the chimney through the fifth valve (37) to be discharged into the environment, and can also be used for carbon capture. The flue gas passes through the first heat exchanger (39) and the second heat exchanger (40) in sequence through the sixth valve (38) to release heat. The flue gas after heat release enters the absorption tower (41) to react with the lean amine liquid to remove CO2. The flue gas then exits the absorption tower (41) and enters the second heat exchanger (40) to absorb the heat of the flue gas before CO2 is removed. The flue gas is then sent to the chimney to be discharged into the environment. The lean amine liquid after absorbing CO2 in the absorption tower (41) is converted into rich amine liquid. The rich amine liquid is pumped into the third heat exchanger (43) through the rich liquid pump (42) to absorb the heat of the lean amine liquid. The rich amine liquid then enters the analysis tower (44) to contact with the water vapor of the amine solution to undergo thermal analysis. CO2 is generated during the analysis process, and the rich amine liquid is converted into lean amine liquid. The lean amine liquid flowing out of the analysis tower (44) is pumped into the third heat exchanger (43) through the lean liquid pump (45) to release heat, and then enters the lean liquid cooler (46) to release heat again. The lean amine liquid after heat release enters the absorption tower (41) to react with the flue gas to absorb CO2 therein; The amine solution produced in the desorption tower (44) is pumped into the first heat exchanger (39) through the amine solution pump (47) to absorb the heat of the flue gas, and then passes through the oil burner (48) to absorb heat again. After absorbing sufficient heat, amine solution water vapor is obtained, and then enters the desorption tower (44) to react with the rich amine liquid flowing into it to precipitate CO2; The gas precipitated in the analysis tower (44) may contain water vapor. The gas is separated by the separator (49) to obtain pure CO2, and the water vapor returns to the analysis tower (44) to heat the rich amine liquid. The CO2 at the outlet of the separator (49) enters the second compressor (50) for compression. The pressurized CO2 enters the second cooler (51) for cooling and is then divided into two streams as needed. One stream enters the third compressor (53) through the seventh valve (52) for compression again and is then used for CO2 storage and transportation. The other stream enters the second throttle valve (55) through the eighth valve (54) for throttling. The throttled CO2 flows into the CO2 liquid storage tank (28) for storage and is used for the supercritical CO2 power cycle.

14. The method for operating a supercritical CO2 thermal power plant with self-supply of CO2 based on carbon capture according to claim 10, characterized in that: The cooling water circulation process specifically includes: The cooling water pump (57) pumps the cooling water in the cooling tower (58) into the first cooler (16) and the second cooler (51) respectively to cool the CO2 therein, and then returns the cooling water to the cooling tower (58).

15. The method for operating a supercritical CO2 thermal power plant with self-supply of CO2 based on carbon capture according to claim 10, characterized in that: During the supercritical CO2 power cycle, the CO2 at the outlet of the first cooler (16) controls the flow rate of the branch through the second valve (18) and the third valve (26), and the third valve (26) controls the opening and closing of the branch flowing through the CO2 liquid storage tank (28); the flue gas at the outlet of the induced draft fan (36) controls the flow rate of the branch through the fifth valve (37) and the sixth valve (38); the CO2 at the outlet of the second cooler (51) controls the flow rate of the branch through the seventh valve (52) and the eighth valve (54); the check valve (19) controls the CO2 in the flow path to flow in only one direction, and after flowing out from the outlet of the wind gasifier (30) through the fourth valve (31), it only flows into the first compressor (20), and does not flow into the first cooler (16) or the first throttle valve (27) through the check valve (19).

16. The method for operating a supercritical CO2 thermal power plant with self-supply of CO2 based on carbon capture according to claim 10, characterized in that: The fuel combustion process and the supercritical CO2 power cycle process exchange energy through the heat exchange riser (5); the hot flue gas formed in the boiler furnace (6) carries a large amount of heat, and when the flue gas enters the carbon capture module, it exchanges energy with the high-temperature superheater (8), high-temperature reheater (12), low-temperature reheater (11), low-temperature superheater (7), economizer (22) and air preheater (25) installed in the horizontal flue and the vertical flue; in the carbon capture module, the heat of the flue gas is further recovered through the first heat exchanger (39) and the second heat exchanger (40), and the temperature of the flue gas entering the absorption tower (41) is reduced to improve the chemical reaction efficiency of carbon capture in the absorption tower; the supercritical CO2 power cycle process exchanges energy with the cooling water cycle through the first cooler (16) and the second cooler (51), completing the cooling of CO2 in the cycle.

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