Carbon capture power plant combination system coupled with solar C-P2G and operation method

Abstract

The invention belongs to the technical field of carbon capture, and discloses a solar C-P2G coupled carbon capture power plant combined system and an operation method. The system comprises a combined cycle power plant subsystem, a carbon capture subsystem, a solar photo-thermal subsystem and a P2G subsystem. The carbon capture subsystem is used for carrying out carbon dioxide recovery on flue gas of the combined cycle power plant subsystem, heat sources such as solar energy and power plant steam are used for providing heat required by reaction for the carbon capture subsystem, and a carbon raw material is provided for the P2G system while the influence of the carbon capture system on the power plant energy efficiency is reduced; the solar photo-thermal subsystem is coordinated to operate through the heat storage system so as to cope with the volatility of renewable energy sources, and gradient utilization of solar heat energy is achieved at the same time; the P2G subsystem consumes redundant electric quantity of the system, and meanwhile, the operation reliability and stability of the coupled solar P2G carbon capture power plant combined system are ensured. The invention further discloses an operation method. According to the invention, low-carbon flexible operation is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon capture and renewable energy utilization, and in particular to a solar-P2G coupled carbon capture power plant combined system and an operation method. Background Art

[0002] Cogeneration is a technology with high energy utilization efficiency. While generating electricity, it uses the steam from the steam turbine to generate electricity for heating, thus realizing the cascade utilization of energy. However, the flue gas discharged during the power generation process of thermal power plants still contains 5% to 10% carbon dioxide. In order to reduce the impact of this part of carbon dioxide on the environment, it is of great significance to develop carbon capture and its utilization technology. At present, the amine absorption method is an efficient carbon capture method that can capture up to 99% purity of carbon dioxide. However, the traditional carbon capture process has certain limitations. It usually requires the extraction of part of the steam from the waste heat boiler to provide heat for the carbon capture process, resulting in a 10-30% reduction in the power generation efficiency of the power plant, which greatly increases the operating cost. Therefore, in order to achieve more environmentally friendly and economical energy production, it is particularly important to explore and apply more efficient carbon capture technology.

[0003] In order to further reduce the dependence of carbon capture technology on fossil energy, the use of renewable energy must be considered. Solar thermal power generation technology is a solar energy technology that uses a linear focusing mechanism to convert solar energy into electrical energy and thermal energy. It can achieve the cascade utilization of solar thermal energy. High-quality thermal energy can be used for power generation, and low-quality thermal energy can provide heat for the carbon capture process, thereby improving the power generation efficiency of the carbon capture power plant system. However, the intermittent and volatile nature of renewable energy will affect the safety and operational reliability of the solar-assisted carbon capture system.

[0004] P2G is a technology that converts electricity into natural gas energy by electrolyzing water to obtain hydrogen and reacting it with carbon dioxide to obtain methane. It is also a suitable solution for long-term storage of electricity in renewable energy power plants. However, P2G requires additional purchase of carbon raw materials, and the high cost of raw materials inhibits its ability to absorb abandoned electricity.

[0005] In summary, designing a carbon capture power plant combined system based on renewable energy can improve energy utilization efficiency, reduce the impact on the environment, absorb and supplement electricity, and ensure the operational reliability and stability of the system, which is of great significance for achieving sustainable development. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a solar-P2G coupled carbon capture power plant combined system, which can effectively solve the problems of high energy consumption of the carbon capture system, volatility of renewable energy and source of P2G raw materials.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A solar-P2G coupled carbon capture power plant combined system includes a combined cycle power plant subsystem, a carbon capture subsystem, a solar thermal subsystem and a P2G subsystem;

[0009] The combined cycle power plant subsystem includes an air compressor, a combustion chamber, a gas turbine, a waste heat boiler, a No. 1 steam turbine, a No. 1 condenser, a steam heat exchanger, a thermal network, a hot water preparation station and a water tank;

[0010] The combustion chamber is provided with a compressed air inlet, a natural gas inlet and a high-temperature and high-pressure flue gas outlet; the compressed air outlet of the air compressor is connected to the compressed air inlet of the combustion chamber; the gas turbine is provided with a flue gas inlet and a flue gas outlet, and the flue gas inlet of the gas turbine is connected to the high-temperature and high-pressure flue gas outlet of the combustion chamber;

[0011] The waste heat boiler is provided with a flue gas channel and a water vapor channel, the flue gas channel is provided with a flue gas inlet and a flue gas outlet, the water vapor channel is provided with a medium-pressure steam outlet, a first condensed water inlet, a low-pressure steam outlet, a second condensed water inlet, a heat medium water inlet and a heat medium water outlet, and the medium-pressure steam outlet is close to the flue gas inlet;

[0012] The flue gas inlet of the waste heat boiler is connected to the flue gas outlet of the gas turbine; the No. 1 steam turbine is provided with a steam inlet and a drain outlet; the medium-pressure steam outlet of the waste heat boiler is connected to the steam inlet of the No. 1 steam turbine, and the drain outlet of the No. 1 steam turbine is connected to the water tank through the No. 1 condenser;

[0013] The steam heat exchanger is provided with a steam inlet, a steam outlet, an amine solution inlet and an amine solution outlet; the low-pressure steam outlet of the waste heat boiler is respectively connected to the steam inlet of the steam heat exchanger and the steam inlet of the thermal network; the steam outlet of the steam heat exchanger is connected to the steam inlet of the thermal network; a valve is provided on the pipeline between the low-pressure steam outlet of the waste heat boiler and the steam inlet of the steam heat exchanger; the low-pressure steam outlet of the thermal network is connected to the water tank;

[0014] The thermal network is provided with a tap water inlet and a tap water outlet; the hot water preparation station is provided with a heat medium water inlet, a heat medium water outlet, a tap water inlet and a tap water outlet; the tap water inlet of the thermal network is connected to the tap water outlet of the hot water preparation station, the heat medium water inlet of the hot water preparation station is connected to the heat medium water outlet of the waste heat boiler, and the heat medium water outlet of the hot water preparation station is connected to the heat medium water inlet of the waste heat boiler through a No. 1 hot water pump; the tap water outlet of the thermal network is transported to the user;

[0015] The carbon capture subsystem includes an absorption tower, an amine liquid heat exchanger, a desorption tower, a solar heat exchanger, and a compression module; the absorption tower is provided with a flue gas inlet, a clean flue gas outlet, a lean amine liquid inlet, and a rich amine liquid outlet; the amine liquid heat exchanger is provided with a rich amine liquid inlet, a rich amine liquid outlet, a lean amine liquid inlet, and a lean amine liquid outlet; the desorption tower is provided with a lean amine liquid outlet, a rich amine liquid first inlet, a rich amine liquid second inlet, a rich amine liquid outlet, and a carbon dioxide outlet; the solar energy converter is provided with an alcoholamine solution inlet and an alcoholamine solution outlet;

[0016] The flue gas outlet of the waste heat boiler is connected to the flue gas inlet of the absorption tower, and a No. 1 cooler is provided on the pipeline connecting the flue gas outlet of the waste heat boiler and the flue gas inlet of the absorption tower, and the clean flue gas outlet of the absorption tower is connected to the atmosphere; the lean amine liquid inlet of the absorption tower is connected to the lean amine liquid outlet of the amine liquid heat exchanger, and the rich amine liquid outlet of the absorption tower is connected to the rich amine liquid inlet of the amine liquid heat exchanger; a rich amine liquid pump is provided on the pipeline connecting the rich amine liquid outlet of the absorption tower and the rich amine liquid inlet of the amine liquid heat exchanger; the lean amine liquid outlet of the desorption tower is connected to the lean amine liquid inlet of the amine liquid heat exchanger, and the rich amine liquid first inlet of the desorption tower is connected to the rich amine liquid outlet of the amine liquid heat exchanger; the carbon dioxide outlet of the desorption tower is connected to the compression module;

[0017] The rich amine liquid outlet of the desorption tower is connected to the alcohol amine solution inlet of the solar heat exchanger, and a regulating valve is provided on the connected pipeline; the rich amine liquid second inlet of the desorption tower is connected to the alcohol amine solution outlet of the solar heat exchanger; the rich amine liquid outlet of the desorption tower is also connected to the alcohol amine solution inlet of the steam heat exchanger, and a solution regulating valve is provided on the connected pipeline; the rich amine liquid second inlet of the desorption tower is also connected to the alcohol amine solution outlet of the steam heat exchanger.

[0018] The flue gas inlet of the absorption tower is arranged at the lower end of the absorption tower, the clean flue gas outlet of the absorption tower is arranged at the top of the absorption tower, the lean amine liquid inlet of the absorption tower is arranged at the upper end of the absorption tower, and the rich amine liquid outlet of the absorption tower is arranged at the bottom of the absorption tower;

[0019] The lean amine liquid inlet of the absorption tower is connected to the lean amine liquid outlet of the amine liquid heat exchanger, and a second cooler is arranged on the connecting pipeline.

[0020] The lean amine liquid outlet of the desorption tower is arranged at the lower end of the desorption tower, the rich amine liquid first inlet is arranged in the middle of the desorption tower, the rich amine liquid second inlet and the rich amine liquid outlet are arranged at the lower end of the desorption tower, and the carbon dioxide outlet is arranged at the top of the desorption tower.

[0021] The solar heat exchanger is also provided with a steam inlet and a steam outlet.

[0022] The solar thermal subsystem includes a heat storage medium heat exchanger, a No. 2 steam turbine, a heat storage medium cold tank, a parabolic trough solar collector and a heat storage medium hot tank; the heat storage medium heat exchanger is provided with a medium water inlet, a medium water outlet, a heat storage medium inlet and a heat storage medium outlet; the No. 2 steam turbine is provided with a steam inlet and a steam outlet; the heat storage medium hot tank is provided with an inlet and an outlet, the heat storage medium cold tank is provided with an inlet and an outlet, and the parabolic trough solar collector is provided with an inlet and an outlet;

[0023] The steam outlet of the solar heat exchanger is connected to the medium water inlet of the heat storage medium heat exchanger, and a No. 2 condenser and a No. 2 hot water pump are arranged in sequence on the connected pipeline, and the No. 2 condenser is close to the steam outlet of the solar heat exchanger; the medium water outlet of the heat storage medium heat exchanger is connected to the steam inlet of the No. 2 steam turbine; the steam outlet of the No. 2 steam turbine is connected to the steam inlet of the solar heat exchanger; the heat storage medium inlet of the heat storage medium heat exchanger is connected to the outlet of the heat storage medium hot tank, and the heat storage medium outlet of the heat storage medium heat exchanger is connected to the inlet of the heat storage medium cold tank; the outlet of the heat storage medium cold tank is connected to the inlet of the parabolic trough solar collector, and the outlet of the parabolic trough solar collector is connected to the inlet of the heat storage medium hot tank.

[0024] The P2G subsystem includes a gas mixer, a heat exchanger, a methanogenization device and a water electrolysis device; the gas mixer is provided with a hydrogen inlet, a carbon dioxide inlet and a mixed gas outlet; the heat exchanger is provided with a mixed gas inlet, a mixed gas outlet, a methane inlet and a methane outlet; the methanogenization device is provided with a mixed gas inlet and a methane outlet; the electrohydrolysis device is provided with a hydrogen outlet and an oxygen outlet;

[0025] The compression module is provided with a carbon dioxide outlet, which is connected to a storage device for compressed carbon dioxide. The carbon dioxide outlet of the compression module is also connected to a carbon dioxide inlet of a gas mixer, and a gas regulating valve is provided on the connected pipeline; the hydrogen inlet of the gas mixer is connected to the hydrogen outlet of the water electrolysis device, and the mixed gas outlet of the gas mixer is connected to the mixed gas inlet of the heat exchanger; the mixed gas outlet of the heat exchanger is connected to the mixed gas inlet of the methanation device, the methane outlet of the methanation device is connected to the methane inlet of the heat exchanger, and the methane outlet of the heat exchanger is connected to the methane storage device.

[0026] The oxygen outlet of the water electrolysis device is connected to the oxygen storage device.

[0027] The upper end of the desorption tower is provided with an inlet for the alcohol amine supplementing liquid; the water electrolysis device is provided with an inlet for water and an inlet for the electrolyte.

[0028] Oxygen and hydrogen are electrolyzed in the water electrolysis device, and part of the captured carbon dioxide and hydrogen are connected to the carbon dioxide inlet of the gas mixer through a regulating valve and mixed in the gas mixture. The mixed gas exchanges heat with the methane prepared by the methanation device in the heat exchanger. After the heat exchange, the mixed gas enters the methanation device to react to obtain methane. The methane after the heat exchange enters the storage device (such as a natural gas storage tank) and can be connected to the natural gas inlet of the combustion chamber.

[0029] The method for operating the solar-P2G coupled carbon capture power plant combined system comprises the following steps:

[0030] 1) Natural gas and air pressurized by the air compressor enter the combustion chamber for mixed combustion, generating high-temperature and high-pressure flue gas; the high-temperature and high-pressure flue gas enters the gas turbine to generate power, and part of the power generated by the gas turbine is used to drive the air compressor, hot water pump and condensate pump; after the high-temperature and high-pressure flue gas enters the gas turbine to generate power, the flue gas enters the flue gas channel in the waste heat boiler, and exchanges heat with the condensed water in the water vapor channel in the waste heat boiler, and the condensed water successively generates medium-pressure steam, low-pressure steam and heat medium water; the medium-pressure steam enters the steam turbine to generate power, and part of the steam is extracted during the power generation process to supply the process For industrial users, medium-pressure steam forms water after generating power in the No. 1 steam turbine, which is discharged through the drain port, condensed by the No. 1 condenser and then enters the water tank. The water in the water tank enters the waste heat boiler through the first condensate inlet and the second condensate inlet in the waste heat boiler to realize circulation; low-pressure steam enters the thermal network to exchange heat with tap water from the hot water preparation station, and is sent to the water tank after the heat exchange is completed; heat medium water enters the hot water preparation station to exchange heat with tap water, and after the heat exchange is completed, the heat medium water re-enters the waste heat boiler through the No. 1 hot water pump for heat exchange; tap water is used as domestic hot water after being heat-exchanged with heat medium water and low-pressure steam;

[0031] 2) The flue gas discharged from the waste heat boiler is cooled by the No. 1 cooler and then enters the absorption tower, where it reacts with the lean amine liquid. Clean flue gas is discharged from the top of the absorption tower, and rich amine liquid flows out from the bottom of the tower. The rich amine liquid flowing out of the absorption tower is pressurized by the rich amine liquid pump and then enters the amine liquid heat exchanger to exchange heat with the lean amine liquid from the desorption tower. The heated rich amine liquid enters the desorption tower from the first rich amine liquid inlet. The lean amine liquid from the desorption tower is cooled by the No. 2 cooler after heat exchange and enters the absorption tower. The rich amine liquid in the desorption tower decomposes carbon dioxide, which is discharged from the carbon dioxide outlet of the desorption tower and enters the compression module. After compression and cooling by the compression module, carbon dioxide is obtained. Compressing carbon dioxide; the heat in the desorption tower is provided by a solar heat exchanger and / or a steam heat exchanger; the heat provided by the solar heat exchanger specifically means that the rich amine liquid in the desorption tower flows out from the rich amine liquid outlet and enters the solar heat exchanger for heat exchange through the solution regulating valve, and then flows back to the desorption tower from the second inlet of the rich amine liquid; the heat provided by the steam heat exchanger means that the rich amine liquid in the desorption tower flows out from the rich amine liquid outlet and enters the steam heat exchanger through the solution regulating valve, and exchanges heat with the low-pressure steam in the steam heat exchanger, and then flows back to the desorption tower from the second inlet of the rich amine liquid; the low-pressure steam in the steam heat exchanger enters the thermal network after heat exchange;

[0032] 3) The rich amine liquid flows out from the rich amine liquid outlet and is regulated by the solution regulating valve to enter the solar heat exchanger for heat exchange, which means that the rich amine liquid exchanges heat with the steam of the circulating water medium in the solar heat exchanger. The circulating water medium after heat exchange is cooled by the condenser and pressurized by the hot water pump and then enters the heat storage medium heat exchanger. The circulating water medium exchanges heat with the high-temperature heat storage medium in the heat storage medium heat exchanger. The circulating water medium is heated into steam, and the steam enters the back pressure steam turbine (No. 2 steam turbine) to generate power. The steam at the outlet of the No. 2 steam turbine enters the solar heat exchanger to exchange heat with the rich amine liquid; the high-temperature The heat storage medium forms a low-temperature heat storage medium after heat exchange in the heat storage medium heat exchanger, and the low-temperature heat storage medium enters the heat storage medium cold tank for storage; the high-temperature heat storage medium comes from the heat storage medium hot tank, and is formed by the parabolic trough solar collector using a linear focusing mechanism to heat the low-temperature heat storage medium from the heat storage medium cold tank; the steam turbine generates power, and the power generated is used for the rich amine liquid pump, hot water pump and compression module. The remaining power is connected to the grid according to the load change. When the carbon capture power plant combined system coupled with solar energy and P2G has excess power that cannot be absorbed, P2G technology is used for energy storage;

[0033] 4) In the P2G subsystem, after the carbon dioxide enters the compression module, part of the carbon dioxide is mixed with the hydrogen from the water electrolysis device in the mixer through the gas regulating valve, and then enters the heat exchanger to exchange heat with the methane from the methanation device. The mixed gas after heat exchange enters the methanation device to react and obtain methane; the methane that has completed heat exchange in the heat exchanger enters the storage device; the water electrolysis device generates hydrogen and oxygen through electrolysis.

[0034] In the carbon capture subsystem, the circulating medium for adsorbing carbon dioxide in the lean amine solution and the rich amine solution is an alcoholamine solution, including an ethanolamine solution and an N-methyldiethanolamine solution. The alcoholamine solution is added through the alcoholamine supplementary liquid inlet at the upper end of the absorption tower.

[0035] The working pressure of the absorption tower is 100-120 kPa, the outlet pressure of the rich amine liquid pump is 200-220 kPa, and the working pressure of the desorption tower is 200-220 kPa; the working temperature of the solar heat exchanger and the steam heat exchanger is 135-170 °C

[0036] The heat storage medium in the solar thermal system includes but is not limited to thermal oil (such as Therminal VP-1, Dowtherm A, Helisol 5A) or molten salt with low melting point, wide temperature range and high specific heat capacity (such as Solarsalt, Hitec solar salt, HitecXL solar salt, etc.).

[0037] The operating temperature of the heat storage medium in the solar thermal system is 200-400°C.

[0038] The parabolic trough solar collector in the solar thermal system consists of four parts: a parabolic reflector, a heat collection assembly, a support structure and a drive structure, and is composed of a plurality of solar heat collection tubes connected in series and then in parallel.

[0039] The water electrolysis device in the P2G system includes but is not limited to a PEM electrolyzer, an alkaline electrolyzer, an AEM electrolyzer, and the like.

[0040] The operating temperature of the methanogenation device in the P2G system is 350-380° C., and the operating pressure is 3-3.5 MPa.

[0041] The heat exchanger in the P2G system preheats the mixed gas to 300-330°C, and the operating pressure ranges from 3 to 3.1 MPa.

[0042] When the combined cycle power plant system is operating stably, when the solar radiation intensity suddenly decreases, the heat collected by the solar collector decreases accordingly. At this time, the flow rate of the heat storage medium entering the solar collector is reduced to keep the outlet temperature of the heat storage medium of the solar collector unchanged; when the solar radiation intensity suddenly increases, the heat collected by the solar collector increases accordingly. At this time, the flow rate of the heat storage medium entering the solar collector is increased to keep the outlet temperature of the heat storage medium of the solar collector unchanged; when the liquid level of the heat storage medium in the hot tank is low, the outlet flow rate of the heat storage medium in the heat storage tank is reduced, the opening of the solution regulating valve of the solar heat exchanger is reduced or closed, the flow rate of the amine solution entering the solar heat exchanger is reduced, the opening of the solution regulating valve of the steam heat exchanger is increased, and part of the low-pressure steam at the outlet of the waste heat boiler is extracted to heat the steam heat exchanger. The adjustment target is to reduce the heat exchange rate between solar heat and amine solution, increase the heat exchange rate between low-pressure steam and amine solution, and ensure the stable operation of the carbon capture system.

[0043] When the heat storage capacity of the solar thermal system is sufficient and the load of the carbon capture power plant combined system coupled with solar energy and P2G increases, the outlet flue gas flow rate in the waste heat boiler increases, and the flow rate of the amine supplementary liquid regulating valve is increased by increasing the flow rate of the amine supplementary liquid, and the flow rate of the heat storage medium entering the heat storage medium heat exchanger is increased, so that the power generation of the No. 2 steam turbine is increased, and the load of the solar heat exchanger is increased accordingly to ensure the capture rate of carbon dioxide in the flue gas; when the heat storage capacity of the solar thermal system is sufficient and the load of the carbon capture power plant combined system coupled with solar energy and P2G decreases, the outlet flue gas flow rate decreases, and the heat storage medium flow rate entering the heat storage medium heat exchanger is reduced, so that the power generation of the No. 2 steam turbine is reduced, and the load of the solar heat exchanger is reduced accordingly. Low to ensure the capture rate of carbon dioxide in flue gas; when the heat storage of solar thermal system is insufficient and the load of carbon capture power plant combined system coupled with solar energy-P2G increases, the outlet flue gas flow rate increases, and the flow of alcohol amine supplementary liquid is increased by opening the regulating valve of alcohol amine supplementary liquid, and the opening of the solution regulating valve of steam heat exchanger is increased to increase the flow of solution entering steam heat exchanger to ensure the capture rate of carbon dioxide in flue gas; when the heat storage of solar thermal system is insufficient and the load of carbon capture power plant combined system coupled with solar energy-P2G decreases, the outlet flue gas flow rate decreases, and the opening of the solution regulating valve of steam heat exchanger is reduced to reduce the flow of solution entering steam heat exchanger to ensure the capture rate of carbon dioxide in flue gas. The water electrolysis device in P2G subsystem absorbs the excess power of the system, electrolyzes hydrogen and oxygen, and hydrogen reacts with part of the captured carbon dioxide in the methanation device to prepare methane, which is input into the natural gas storage tank to maintain safe and stable operation of the system.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] (1) The solar-P2G coupled carbon capture power plant combined system of the present invention applies solar thermal technology to the carbon capture power plant process, and provides heat for the steam cycle through the solar thermal system. The steam cycle can simultaneously realize power generation and heat supply for the carbon capture process, thus solving the problem of excessive energy consumption of traditional carbon capture power plants. It not only reduces the consumption of fossil energy in power plants, realizes flexible and low-carbon operation of the system, but also ensures the stability and reliability of system operation.

[0046] (2) The solar-P2G coupled carbon capture power plant combined system of the present invention applies P2G technology to a solar-assisted carbon capture power plant, which not only solves the problem of the source of carbon raw materials for P2G technology, but also has the ability to reduce system operating costs and smooth the volatility of renewable energy by absorbing excess electricity from the solar thermal system and the combined cycle power plant system.

[0047] The solar-P2G coupled carbon capture power plant combined system of the present invention solves the problems of huge energy consumption of traditional carbon capture power plants, impact of renewable energy volatility on system operation stability and safety, and high carbon raw material costs of P2G technology, and provides a theoretical basis and technical guidance for the construction of carbon capture power plant systems based on renewable energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 Schematic diagram of the carbon capture power plant combined system coupled with solar energy-P2G of the present invention; 1-air compressor, 2-combustion chamber, 3-gas turbine, 4-waste heat boiler, 5-No. 1 steam turbine, 6-No. 1 condenser, 7-steam heat exchanger, 8-thermal network, 9-hot water preparation station, 10-No. 1 hot water pump, 11-No. 1 cooler, 12: absorption tower, 13-rich amine liquid pump, 14-amine liquid heat exchanger, 15-desorption tower, 16-No. 2 cooler, 17-solar heat exchanger, 18-No. 2 condenser, 19-No. 2 hot water pump, 20-heat storage medium heat exchanger, 21-No. 2 steam turbine, 22-heat storage medium cold tank, 23-parabolic trough solar collector, 24-heat storage medium hot tank, 25-compression module, 26-gas mixer, 27-heat exchanger, 28-methanization device, 29-water electrolysis device, 30-water tank. DETAILED DESCRIPTION

[0049] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. These embodiments are only used to illustrate the present invention, but not to limit the present invention.

[0050] A solar-P2G coupled carbon capture power plant combined system comprises a combined cycle power plant subsystem, a carbon capture subsystem, a solar thermal subsystem and a P2G subsystem;

[0051] The combined cycle power plant subsystem includes an air compressor 1, a combustion chamber 2, a gas turbine 3, a waste heat boiler 4, a No. 1 steam turbine 5, a No. 1 condenser 6, a steam heat exchanger 7, a thermal network 8, a hot water preparation station 9 and a water tank 30;

[0052] The combustion chamber 2 is provided with a compressed air inlet, a natural gas inlet and a high-temperature and high-pressure flue gas outlet; the compressed air outlet of the air compressor 1 is connected to the compressed air inlet of the combustion chamber 2; the gas turbine 3 is provided with a flue gas inlet and a flue gas outlet, and the flue gas inlet of the gas turbine 3 is connected to the high-temperature and high-pressure flue gas outlet of the combustion chamber 2; the waste heat boiler 4 is provided with a flue gas channel and a water vapor channel, the flue gas channel is provided with a flue gas inlet and a flue gas outlet, the water vapor channel is provided with a medium-pressure steam outlet, a first condensed water inlet, a low-pressure steam outlet, a second condensed water inlet, a heat medium water inlet and a heat medium water outlet, and the medium-pressure steam outlet is close to the flue gas inlet;

[0053] The flue gas inlet of the waste heat boiler 4 is connected to the flue gas outlet of the gas turbine 3; the No. 1 steam turbine 5 is provided with a steam inlet and a drain outlet; the medium-pressure steam outlet of the waste heat boiler 4 is connected to the steam inlet of the No. 1 steam turbine 5, and the drain outlet of the No. 1 steam turbine 5 is connected to the water tank 30 through the No. 1 condenser 6;

[0054] The steam heat exchanger 7 is provided with a steam inlet, a steam outlet, an amine solution inlet and an amine solution outlet; the low-pressure steam outlet of the waste heat boiler 4 is connected to the steam inlet of the steam heat exchanger 7 and the thermal network 8 respectively; the steam outlet of the steam heat exchanger 7 is connected to the steam inlet of the thermal network 8; a valve is provided on the pipeline between the low-pressure steam outlet of the waste heat boiler 4 and the steam inlet of the steam heat exchanger 7; the low-pressure steam outlet of the thermal network 8 is connected to the water tank 30;

[0055] The thermal network 8 is provided with a tap water inlet and a tap water outlet; the hot water preparation station 9 is provided with a heat medium water inlet, a heat medium water outlet, a tap water inlet and a tap water outlet; the tap water inlet of the thermal network 8 is connected to the tap water outlet of the hot water preparation station 9, the heat medium water inlet of the hot water preparation station 9 is connected to the heat medium water outlet of the waste heat boiler 4, and the heat medium water outlet of the hot water preparation station 9 is connected to the heat medium water inlet of the waste heat boiler 4 through a No. 1 hot water pump 10; the tap water outlet of the thermal network 8 is transported to the user;

[0056] The carbon capture system comprises an absorption tower 12, an amine liquid heat exchanger 14, a desorption tower 15, a solar heat exchanger 17, and a compression module 25; the absorption tower 12 is provided with a flue gas inlet, a clean flue gas outlet, a lean amine liquid inlet, and a rich amine liquid outlet; the amine liquid heat exchanger 14 is provided with a rich amine liquid inlet, a rich amine liquid outlet, a lean amine liquid inlet, and a lean amine liquid outlet; the desorption tower 15 is provided with a lean amine liquid outlet, a first rich amine liquid inlet, a second rich amine liquid inlet, a rich amine liquid outlet, and a carbon dioxide outlet; the solar energy converter 17 is provided with an alcoholamine solution inlet and an alcoholamine solution outlet;

[0057] The flue gas outlet of the waste heat boiler 4 is connected to the flue gas inlet of the absorption tower 12, and a No. 1 cooler 11 is provided on the pipeline connecting the flue gas outlet of the waste heat boiler 4 and the flue gas inlet of the absorption tower 12, and the clean flue gas outlet of the absorption tower 12 is connected to the atmosphere; the lean amine liquid inlet of the absorption tower 12 is connected to the lean amine liquid outlet of the amine liquid heat exchanger 14, and a No. 2 cooler 16 is provided on the connected pipeline; the rich amine liquid outlet of the absorption tower 12 is connected to the rich amine liquid inlet of the amine liquid heat exchanger 14; the rich amine liquid outlet of the absorption tower 12 is connected to the rich amine liquid inlet of the amine liquid heat exchanger 14. A rich amine liquid pump 13 is provided on the pipeline connecting the rich amine liquid outlet of the absorption tower 12 and the rich amine liquid inlet of the amine liquid heat exchanger 14; the lean amine liquid outlet of the desorption tower 15 is connected to the lean amine liquid inlet of the amine liquid heat exchanger 14, and the rich amine liquid first inlet of the desorption tower 15 is connected to the rich amine liquid outlet of the amine liquid heat exchanger 14; the carbon dioxide outlet of the desorption tower 15 is connected to the compression module 25;

[0058] The rich amine liquid outlet of the desorption tower 15 is connected to the alcoholamine solution inlet of the solar heat exchanger 17, and a regulating valve is provided on the connected pipeline; the rich amine liquid second inlet of the desorption tower 15 is connected to the alcoholamine solution outlet of the solar heat exchanger 17; the rich amine liquid outlet of the desorption tower 15 is also connected to the alcoholamine solution inlet of the steam heat exchanger 7, and a solution regulating valve is provided on the connected pipeline; the rich amine liquid second inlet of the desorption tower 15 is also connected to the alcoholamine solution outlet of the steam heat exchanger 7.

[0059] The flue gas inlet of the absorption tower 12 is arranged at the lower end of the absorption tower 12, the clean flue gas outlet of the absorption tower 12 is arranged at the top of the absorption tower 12, the lean amine liquid inlet of the absorption tower 12 is arranged at the upper end of the absorption tower 12, and the rich amine liquid outlet of the absorption tower 12 is arranged at the bottom of the absorption tower 12.

[0060] The lean amine liquid outlet of the desorption tower 15 is arranged at the lower end of the desorption tower 15, the rich amine liquid first inlet is arranged in the middle of the desorption tower 15, the rich amine liquid second inlet and the rich amine liquid outlet are arranged at the lower end of the desorption tower 15, and the carbon dioxide outlet is arranged at the top of the desorption tower 15.

[0061] The solar heat exchanger 17 is also provided with a steam inlet and a steam outlet.

[0062] The solar thermal system includes a heat storage medium heat exchanger 20, a No. 2 steam turbine 21, a heat storage medium cold tank 22, a parabolic trough solar collector 23 and a heat storage medium hot tank 24; the heat storage medium heat exchanger 20 is provided with a medium water inlet, a medium water outlet, a heat storage medium inlet and a heat storage medium outlet; the No. 2 steam turbine 21 is provided with a steam inlet and a steam outlet; the heat storage medium hot tank 24 is provided with an inlet and an outlet, the heat storage medium cold tank 22 is provided with an inlet and an outlet, and the parabolic trough solar collector 23 is provided with an inlet and an outlet;

[0063] The steam outlet of the solar heat exchanger 17 is connected to the medium water inlet of the heat storage medium heat exchanger 20, and a No. 2 condenser 18 and a hot water pump 19 are sequentially arranged on the connected pipeline, and the No. 2 condenser 18 is close to the steam outlet; the medium water outlet of the heat storage medium heat exchanger 20 is connected to the steam inlet of the No. 2 steam turbine; the steam outlet of the No. 2 steam turbine 21 is connected to the steam inlet of the solar heat exchanger 17; the heat storage medium inlet of the heat storage medium heat exchanger 20 is connected to the outlet of the heat storage medium hot tank 24, and the heat storage medium outlet of the heat storage medium heat exchanger is connected to the inlet of the heat storage medium cold tank 22; the outlet of the heat storage medium cold tank 22 is connected to the inlet of the parabolic trough solar collector 23, and the outlet of the parabolic trough solar collector 23 is connected to the inlet of the heat storage medium hot tank 24.

[0064] The P2G system includes a gas mixer 26, a heat exchanger 27, a methanogen 28 and a water electrolysis device 29; the gas mixer 26 is provided with a hydrogen inlet, a carbon dioxide inlet and a mixed gas outlet; the heat exchanger 27 is provided with a mixed gas inlet, a mixed gas outlet, a methane inlet and a methane outlet; the methanogen 28 is provided with a mixed gas inlet and a methane outlet; the water electrolysis device 29 is provided with a hydrogen outlet and an oxygen outlet;

[0065] The compression module 25 is provided with a carbon dioxide outlet, and the carbon dioxide outlet of the compression module 25 is connected to a storage device for compressed carbon dioxide. The carbon dioxide outlet of the compression module 25 is also connected to a carbon dioxide inlet of a gas mixer 26, and a gas regulating valve is provided on the connected pipeline; the hydrogen inlet of the gas mixer 26 is connected to the hydrogen outlet of the water electrolysis device 29, and the mixed gas outlet of the gas mixer 26 is connected to the mixed gas inlet of the heat exchanger 27; the mixed gas outlet of the heat exchanger 27 is connected to the mixed gas inlet of the methanation device 28, the methane outlet of the methanation device 28 is connected to the methane inlet of the heat exchanger 27, and the methane outlet of the heat exchanger 27 is connected to the storage device for methane.

[0066] The oxygen outlet of the water electrolysis device 29 is connected to an oxygen storage device.

[0067] Oxygen and hydrogen are electrolyzed in the water electrolysis device 29, and part of the captured carbon dioxide and hydrogen are connected to the carbon dioxide inlet of the gas mixer through a regulating valve and mixed in the gas mixer. The mixed gas exchanges heat with the methane prepared by the methanation device 28 in the heat exchanger. After the heat exchange, the mixed gas enters the methanation device 28 to react to obtain methane. The methane after the heat exchange enters the storage device (such as a natural gas storage tank) and can be connected to the natural gas inlet of the combustion chamber 2.

[0068] The method for operating the solar-P2G coupled carbon capture power plant combined system comprises the following steps:

[0069] 1) Natural gas from the gas pipeline and air pressurized by the air compressor 1 enter the combustion chamber 2 for mixed combustion to generate high-temperature and high-pressure flue gas; the high-temperature and high-pressure flue gas enters the gas turbine 3 to generate power, and part of the power generated by the gas turbine 3 is used to drive the air compressor, the hot water pump and the condensate pump; after the high-temperature and high-pressure flue gas enters the gas turbine 3 to generate power, the flue gas coming out of the flue gas outlet of the gas turbine 3 enters the flue gas channel in the waste heat boiler 4, and exchanges heat with the condensed water in the water vapor channel in the waste heat boiler 4 (the condensed water in the water vapor channel is the circulating water medium entering from the first condensed water inlet and the second condensed water inlet of the water vapor channel and the circulating water medium entering from the heat medium water inlet of the waste heat boiler), and the condensed water successively generates medium-pressure steam, low-pressure steam and heat medium water; the medium-pressure steam enters the No. 1 steam generator The steam turbine 5 generates power (extraction condensing steam turbine), and part of the steam is extracted during the process of generating power to supply industrial users. The medium-pressure steam forms water after the No. 1 steam turbine 5 generates power, and is discharged through the drain port. After being condensed by the No. 1 condenser 6, it enters the water tank 30. The water in the water tank 30 enters the waste heat boiler 4 through the first condensate inlet and the second condensate inlet in the waste heat boiler 4 to realize circulation; the low-pressure steam enters the thermal network 8 to exchange heat with the tap water from the hot water preparation station 9, and is sent to the water tank 30 after the heat exchange is completed; the heat medium water enters the hot water preparation station 9 to exchange heat with the tap water, and after the heat exchange is completed, the heat medium water re-enters the waste heat boiler 4 through the hot water pump 10 for heat exchange; the tap water is used as domestic hot water after being heat-exchanged with the heat medium water and the low-pressure steam; the temperature of the flue gas discharged from the waste heat boiler 4 is 140°C;

[0070] 2) The flue gas discharged from the waste heat boiler 4 is cooled by the first cooler 11 and then enters the absorption tower 12, where it reacts with the lean amine liquid in the absorption tower 12. Clean flue gas is discharged from the top of the absorption tower 12, and rich amine liquid flows out from the bottom of the tower; the rich amine liquid flowing out of the absorption tower 12 is pressurized by the rich amine liquid pump 13, and then enters the amine liquid heat exchanger 14 to exchange heat with the lean amine liquid from the desorption tower 15. The heated rich amine liquid enters the desorption tower 15 from the first rich amine liquid inlet, and the lean amine liquid from the desorption tower 15 is cooled by the second cooler 16 after heat exchange and enters the absorption tower 12; carbon dioxide is decomposed from the rich amine liquid in the desorption tower 15, and the carbon dioxide is discharged from the carbon dioxide outlet of the desorption tower 15 and enters the compression module 25. After compression and cooling by the compression module 25, compressed carbon dioxide is obtained; the heat in the desorption tower 15 is generated by solar energy. The heat exchanger 17 and / or the steam heat exchanger 7 provide heat; the heat provided by the solar heat exchanger 17 specifically means that the rich amine liquid in the desorption tower 15 flows out from the rich amine liquid outlet and enters the solar heat exchanger 17 through the solution regulating valve for heat exchange, and then flows back to the desorption tower 15 from the second inlet of the rich amine liquid; the heat provided by the steam heat exchanger 7 means that the rich amine liquid in the desorption tower 15 flows out from the rich amine liquid outlet and enters the steam heat exchanger 7 through the solution regulating valve, and exchanges heat with the low-pressure steam in the steam heat exchanger, and then flows back to the desorption tower 15 from the second inlet of the rich amine liquid; the low-pressure steam in the steam heat exchange enters the thermal network 8 after heat exchange; the heat required by the desorption tower 15 is preferentially provided by the solar heat exchanger 17, and when the heat provided by the solar heat exchanger 17 is insufficient, the steam heat exchanger 7 supplements the heat;

[0071] The carbon capture system uses MEA solution as a circulating medium, which has the characteristics of fast absorption rate and low price, and its lean liquid load is 0.25; the top working pressure of the absorption tower 12 is 110kPa, and the pressure drop of the whole tower is 10kPa; the outlet pressure of the rich amine liquid pump 13 is 220kPa; the top working pressure of the desorption tower 15 is 210kPa, and the pressure drop of the whole tower is 200kPa;

[0072] The temperature of the flue gas cooled by the No. 1 cooler 11 is 40°C; the temperature of the lean amine liquid cooled by the No. 2 cooler 16 is 40°C; the temperature of the rich amine liquid outlet of the amine liquid heat exchanger 14 is 100°C; the operating temperature range of the desorption tower 15 is 120-125°C; the carbon dioxide outlet temperature range of the desorption tower 15 is 25-35°C; the carbon dioxide outlet temperature of the compression module 25 is 25°C, and the outlet pressure is 11MPa; the operating temperature range of the solar heat exchanger 17 and the steam heat exchanger 7 is 135-170°C;

[0073] 3) The rich amine liquid flows out from the rich amine liquid outlet and is regulated by the solution regulating valve to enter the solar heat exchanger 17 for heat exchange, which means that the rich amine liquid exchanges heat with the steam of the circulating water medium in the solar heat exchanger 17. The circulating water medium after heat exchange is cooled by the second condenser 18 and pressurized by the hot water pump 19 before entering the heat storage medium heat exchanger 20. The circulating water medium exchanges heat with the high-temperature heat storage medium in the heat storage medium heat exchanger 20. The circulating water medium is heated into steam, which enters the second steam turbine 21 (back pressure steam turbine) to generate power. The steam at the outlet of the second steam turbine enters the solar heat exchanger 17 to exchange heat with the rich amine liquid. The high-temperature storage medium After the heat medium is heat exchanged in the heat storage medium heat exchanger 20, a low-temperature heat storage medium is formed, and the low-temperature heat storage medium enters the heat storage medium cold tank 22 for storage; the high-temperature heat storage medium comes from the heat storage medium hot tank 24, and is formed by the parabolic trough solar collector 23 using a linear focusing mechanism to heat the low-temperature heat storage medium from the heat storage medium cold tank 22; the No. 2 steam turbine 21 generates power, and the power generated is used for the rich amine liquid pump 13, the hot water pump 19 and the compression module 25. The remaining power is connected to the grid according to the load change. When the carbon capture power plant combined system coupled with solar energy and P2G has excess power that cannot be absorbed, P2G technology is used to store energy;

[0074] The high-temperature heat storage medium and the low-temperature heat storage medium in the solar thermal system are molten salts, which have the characteristics of low melting point, wide temperature range and high specific heat capacity, and the mass ratio of Ca(NO3)2:KNO3:NaNO3 is 42%:43%:15%; the parabolic trough solar collector in the solar thermal system consists of four parts: a parabolic reflector, a heat collection component, a support structure and a drive structure; the parabolic reflector model adopts Ultimate Trough; it is composed of multiple solar collector tubes connected in series and then in parallel, and the collector tube model adopts a high-temperature molten salt collector tube HCEMS-11, and its maximum operating temperature is 580°C;

[0075] The operating temperature range of the heat storage medium in the solar thermal system is 200-400°C, the inlet temperature of the molten salt of the parabolic trough solar collector is 200°C, the outlet temperature is 400°C, the operating temperature of the molten salt cold tank is 200°C, and the operating temperature of the molten salt hot tank is 400°C;

[0076] The steam circulation medium in the solar thermal system is water, and its operating temperature range is 120-350°C. The steam outlet temperature of the heat storage medium heat exchanger (molten salt heat exchanger) 20 is 350°C, and the medium water outlet temperature of the second condenser 18 is 135°C. The outlet pressure of the hot water pump 19 in the solar thermal system is 4MPa; the steam outlet pressure of the second steam turbine 21 is 0.3MPa;

[0077] The solar thermal system operates by using a reflector system to focus sunlight at one point to generate a high temperature of more than 1200°C, thereby heating a heat transfer medium such as heat transfer oil or molten salt, and then heating water vapor through the heat transfer medium, and the water vapor drives a turbine to generate electricity;

[0078] 4) In the P2G system, after the carbon dioxide enters the compression module 25, part of the carbon dioxide is mixed with the hydrogen from the water electrolysis device 29 in the gas mixer 26 through the gas regulating valve, and then enters the heat exchanger 27 to exchange heat with the methane from the methanation device 28. The mixed gas after heat exchange enters the methanation device 28 to react and obtain methane; the methane that has completed heat exchange in the heat exchanger 27 enters the storage device; the water electrolysis device 29 generates hydrogen and oxygen through electrolysis.

[0079] The water electrolysis device in the P2G system is a PEM electrolyzer, whose operating temperature is 80°C and the pure water inlet temperature is 80°C.

[0080] The operating temperature of the methanogenation device in the P2G system is 380°C and the operating pressure is 3MPa.

[0081] The heat exchanger 27 in the P2G system preheats the mixed gas to 320° C., and the working pressure is 3.1 MPa.

[0082] When the combined cycle power plant system of the present invention operates stably, when the solar radiation intensity suddenly decreases, the heat collected by the solar collector decreases accordingly. At this time, the flow rate of the heat storage medium entering the solar collector is reduced, so that the outlet temperature of the heat storage medium of the solar collector remains unchanged; when the solar radiation intensity suddenly increases, the heat collected by the solar collector increases accordingly. At this time, the flow rate of the heat storage medium entering the solar collector is increased, so that the outlet temperature of the heat storage medium of the solar collector remains unchanged; when the liquid level of the heat storage medium in the hot tank is low, the outlet flow rate of the heat storage medium in the hot tank is reduced, the opening of the solution regulating valve of the solar heat exchanger is reduced or closed, the flow rate of the alcoholamine solution entering the solar heat exchanger is reduced, the opening of the solution regulating valve of the steam heat exchanger is increased, and part of the low-pressure steam at the outlet of the waste heat boiler is extracted to heat the steam heat exchanger. The adjustment target is to reduce the heat exchange rate between the solar heat and the alcoholamine solution, increase the heat exchange rate between the low-pressure steam and the alcoholamine solution, and ensure the stable operation of the carbon capture system.

[0083] When the heat storage capacity of the solar thermal system is sufficient and the load of the carbon capture power plant combined system coupled with solar energy-P2G increases, the outlet flue gas flow rate increases, and the opening of the amine supplementary liquid regulating valve is increased to increase the flow of the amine supplementary liquid, and increase the heat storage medium flow entering the heat storage medium heat exchanger 20 (molten salt heat exchanger), so that the power generation of the No. 2 steam turbine 21 increases, and the load of the solar heat exchanger increases accordingly to ensure the capture rate of carbon dioxide in the flue gas; when the heat storage capacity of the solar thermal system is sufficient and the load of the carbon capture power plant combined system coupled with solar energy-P2G decreases, the outlet flue gas flow rate decreases, and the heat storage medium flow entering the heat storage medium heat exchanger 20 is reduced, so that the power generation of the No. 2 steam turbine 21 decreases, and the load of the solar heat exchanger The temperature of the flue gas is reduced accordingly to ensure the capture rate of carbon dioxide in the flue gas; when the solar thermal system has insufficient heat storage and the load of the carbon capture power plant combined system coupled with solar energy-P2G increases, the outlet flue gas flow rate increases, and the opening of the alcohol amine supplementary liquid regulating valve is increased to increase the flow of alcohol amine supplementary liquid, and the opening of the solution regulating valve of the steam heat exchanger 7 is increased to increase the flow of solution entering the steam heat exchanger 7 to ensure the capture rate of carbon dioxide in the flue gas; when the solar thermal system has insufficient heat storage and the load of the carbon capture power plant combined system coupled with solar energy-P2G decreases, the outlet flue gas flow rate decreases, and the opening of the solution regulating valve of the steam heat exchanger 7 is reduced to reduce the flow of solution entering the steam heat exchanger 7 to ensure the capture rate of carbon dioxide in the flue gas. The water electrolysis device in the P2G system consumes excess power in the system, electrolyzes hydrogen and oxygen, and the hydrogen reacts with part of the captured carbon dioxide in the methanation device 28 to prepare methane, which is input into the natural gas storage tank to maintain safe and stable operation of the system.

[0084] The present embodiment proposes a solar-P2G coupled carbon capture power plant combined system that can simultaneously solve the problem of the carbon capture system seriously reducing the power generation efficiency of the combined cycle power plant, the problem of unstable operation of the carbon capture power plant coupled with solar energy, and the problem of carbon source cost of P2G technology, thereby achieving the flexibility and stability of the system and clean and low-carbon power generation, which is of great significance to ensuring the sustainable development of the carbon capture power system based on renewable energy.

[0085] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention shall be equivalent replacement methods and shall be included in the protection scope of the present invention.

Claims

1. A solar-P2G coupled carbon capture power plant system, characterized by: It includes combined cycle power plant subsystem, carbon capture subsystem, solar thermal subsystem and P2G subsystem; The combined cycle power plant subsystem includes an air compressor (1), a combustion chamber (2), a gas turbine (3), a waste heat boiler (4), a No. 1 steam turbine (5), a No. 1 condenser (6), a steam heat exchanger (7), a thermal network (8), a hot water preparation station (9) and a water tank (30); The combustion chamber (2) is provided with a compressed air inlet, a natural gas inlet and a high-temperature and high-pressure flue gas outlet; The compressed air outlet of the air compressor (1) is connected to the compressed air inlet of the combustion chamber (2); the gas turbine (3) is provided with a flue gas inlet and a flue gas outlet, and the flue gas inlet of the gas turbine (3) is connected to the high-temperature and high-pressure flue gas outlet of the combustion chamber (2); The waste heat boiler (4) is provided with a flue gas channel and a water vapor channel, the flue gas channel is provided with a flue gas inlet and a flue gas outlet, the water vapor channel is provided with a medium-pressure steam outlet, a first condensed water inlet, a low-pressure steam outlet, a second condensed water inlet, a heat medium water inlet and a heat medium water outlet, the medium-pressure steam outlet is close to the flue gas inlet; The flue gas inlet of the waste heat boiler (4) is connected to the flue gas outlet of the gas turbine (3); the first steam turbine (5) is provided with a steam inlet and a drain outlet; the medium-pressure steam outlet of the waste heat boiler (4) is connected to the steam inlet of the first steam turbine (5), and the drain outlet of the first steam turbine (5) is connected to the water tank (30) through the first condenser (6); The steam heat exchanger (7) is provided with a steam inlet, a steam outlet, an alcoholamine solution inlet and an alcoholamine solution outlet; the low-pressure steam outlet of the waste heat boiler (4) is respectively connected to the steam inlet of the steam heat exchanger (7) and the steam inlet of the thermal network (8); the steam outlet of the steam heat exchanger (7) is connected to the steam inlet of the thermal network (8); a valve is provided on the pipeline between the low-pressure steam outlet of the waste heat boiler (4) and the steam inlet of the steam heat exchanger (7); the low-pressure steam outlet of the thermal network (8) is connected to the water tank (30); The thermal network (8) is provided with a tap water inlet and a tap water outlet; the hot water preparation station (9) is provided with a heat medium water inlet, a heat medium water outlet, a tap water inlet and a tap water outlet; the tap water inlet of the thermal network (8) is connected to the tap water outlet of the hot water preparation station (9), the heat medium water inlet of the hot water preparation station (9) is connected to the heat medium water outlet of the waste heat boiler (4), and the heat medium water outlet of the hot water preparation station (9) is connected to the heat medium water inlet of the waste heat boiler (4) via a No. 1 hot water pump (10); the tap water outlet of the thermal network (8) is transported to the user; The carbon capture subsystem comprises an absorption tower (12), an amine liquid heat exchanger (14), a desorption tower (15), a solar heat exchanger (17), and a compression module (25); the absorption tower (12) is provided with a flue gas inlet, a clean flue gas outlet, a lean amine liquid inlet, and a rich amine liquid outlet; the amine liquid heat exchanger (14) is provided with a rich amine liquid inlet, a rich amine liquid outlet, a lean amine liquid inlet, and a lean amine liquid outlet; the desorption tower (15) is provided with a lean amine liquid outlet, a first rich amine liquid inlet, a second rich amine liquid inlet, a rich amine liquid outlet, and a carbon dioxide outlet; the solar energy converter (17) is provided with an alcoholamine solution inlet and an alcoholamine solution outlet; The flue gas outlet of the waste heat boiler (4) is connected to the flue gas inlet of the absorption tower (12); a first cooler (11) is provided on the pipeline connecting the flue gas outlet of the waste heat boiler (4) and the flue gas inlet of the absorption tower (12); the clean flue gas outlet of the absorption tower (12) is connected to the atmosphere; the lean amine liquid inlet of the absorption tower (12) is connected to the lean amine liquid outlet of the amine liquid heat exchanger (14); the rich amine liquid outlet of the absorption tower (12) is connected to the rich amine liquid outlet of the amine liquid heat exchanger (14); ); a rich amine liquid pump (13) is provided on a pipeline connecting the rich amine liquid outlet of the absorption tower (12) and the rich amine liquid inlet of the amine liquid heat exchanger (14); a lean amine liquid outlet of the desorption tower (15) is connected to the lean amine liquid inlet of the amine liquid heat exchanger (14), and a rich amine liquid first inlet of the desorption tower (15) is connected to the rich amine liquid outlet of the amine liquid heat exchanger (14); a carbon dioxide outlet of the desorption tower (15) is connected to a compression module (25); The rich amine liquid outlet of the desorption tower (15) is connected to the alcohol amine solution inlet of the solar heat exchanger (17), and a regulating valve is provided on the connected pipeline; the rich amine liquid second inlet of the desorption tower (15) is connected to the alcohol amine solution outlet of the solar heat exchanger (17); the rich amine liquid outlet of the desorption tower (15) is also connected to the alcohol amine solution inlet of the steam heat exchanger (7), and a solution regulating valve is provided on the connected pipeline; the rich amine liquid second inlet of the desorption tower (15) is also connected to the alcohol amine solution outlet of the steam heat exchanger (7); The solar heat exchanger (17) is also provided with a steam inlet and a steam outlet; The solar thermal subsystem comprises a heat storage medium heat exchanger (20), a No. 2 steam turbine (21), a heat storage medium cold tank (22), a parabolic trough solar collector (23) and a heat storage medium hot tank (24); the heat storage medium heat exchanger (20) is provided with a medium water inlet, a medium water outlet, a heat storage medium inlet and a heat storage medium outlet; the No. 2 steam turbine (21) is provided with a steam inlet and a steam outlet; the heat storage medium hot tank (24) is provided with an inlet and an outlet, the heat storage medium cold tank (22) is provided with an inlet and an outlet, and the parabolic trough solar collector (23) is provided with an inlet and an outlet; The steam outlet of the solar heat exchanger (17) is connected to the medium water inlet of the heat storage medium heat exchanger (20), and the connecting pipeline is provided with a No. 2 condenser (18) and a No. 2 hot water pump (19) in sequence, and the No. 2 condenser (18) is close to the steam outlet of the solar heat exchanger (17); the medium water outlet of the heat storage medium heat exchanger (20) is connected to the steam inlet of the No. 2 steam turbine (21); the steam outlet of the No. 2 steam turbine (21) is connected to the steam inlet of the solar heat exchanger (17); the heat storage medium inlet of the heat storage medium heat exchanger (20) is connected to the outlet of the heat storage medium hot tank (24), and the heat storage medium outlet of the heat storage medium heat exchanger (20) is connected to the inlet of the heat storage medium cold tank (22); the outlet of the heat storage medium cold tank (22) is connected to the inlet of the parabolic trough solar collector (23), and the outlet of the parabolic trough solar collector (23) is connected to the inlet of the heat storage medium hot tank (24); The P2G subsystem comprises a gas mixer (26), a heat exchanger (27), a methanogenization device (28) and a water electrolysis device (29); the gas mixer (26) is provided with a hydrogen inlet, a carbon dioxide inlet and a mixed gas outlet; the heat exchanger (27) is provided with a mixed gas inlet, a mixed gas outlet, a methane inlet and a methane outlet; the methanogenization device (28) is provided with a mixed gas inlet and a methane outlet; the water electrolysis device (29) is provided with a hydrogen outlet and an oxygen outlet; The compression module (25) is provided with a carbon dioxide outlet, and the carbon dioxide outlet of the compression module (25) is connected to a storage device for compressed carbon dioxide. The carbon dioxide outlet of the compression module (25) is also connected to a carbon dioxide inlet of a gas mixer (26), and a gas regulating valve is provided on the connected pipeline; the hydrogen inlet of the gas mixer (26) is connected to a hydrogen outlet of a water electrolysis device (29), and the mixed gas outlet of the gas mixer (26) is connected to a mixed gas inlet of a heat exchanger (27); the mixed gas outlet of the heat exchanger (27) is connected to a mixed gas inlet of a methanation device (28), the methane outlet of the methanation device (28) is connected to a methane inlet of the heat exchanger (27), and the methane outlet of the heat exchanger (27) is connected to a methane storage device.

2. The solar-P2G coupled carbon capture power plant combined system according to claim 1, characterized in that: The flue gas inlet of the absorption tower (12) is arranged at the lower end of the absorption tower (12), the clean flue gas outlet of the absorption tower (12) is arranged at the top of the absorption tower (12), the lean amine liquid inlet of the absorption tower (12) is arranged at the upper end of the absorption tower (12), and the rich amine liquid outlet of the absorption tower (12) is arranged at the bottom of the absorption tower (12); The lean amine liquid inlet of the absorption tower (12) is connected to the lean amine liquid outlet of the amine liquid heat exchanger (14), and a second cooler (16) is provided on the connecting pipeline; The lean amine liquid outlet of the desorption tower (15) is arranged at the lower end of the desorption tower (15), the rich amine liquid first inlet is arranged at the middle of the desorption tower (15), the rich amine liquid second inlet and the rich amine liquid outlet are arranged at the lower end of the desorption tower (15), and the carbon dioxide outlet is arranged at the top of the desorption tower (15); The oxygen outlet of the water electrolysis device (29) is connected to an oxygen storage device.

3. The solar-P2G coupled carbon capture power plant combined system according to claim 1, characterized in that: The upper end of the desorption tower (15) is provided with an inlet for the alcohol amine supplementary liquid; the water electrolysis device (29) is provided with an inlet for water and an inlet for the electrolyte.

4. The method for operating the solar-P2G coupled carbon capture power plant combined system according to any one of claims 1 to 3, characterized in that: The following steps are involved: 1) Natural gas and air pressurized by an air compressor (1) enter a combustion chamber (2) and are mixed and burned to produce high-temperature and high-pressure flue gas; High-temperature and high-pressure flue gas enters the gas turbine (3) to generate power, and part of the power generated by the gas turbine (3) is used to drive an air compressor, a hot water pump and a condensate pump; after the high-temperature and high-pressure flue gas enters the gas turbine (3) to generate power, the flue gas from the flue gas outlet of the gas turbine (3) enters the flue gas channel in the waste heat boiler (4) and exchanges heat with the condensed water in the water vapor channel in the waste heat boiler (40), the condensed water in the water vapor channel is the circulating water medium entering from the first condensed water inlet and the second condensed water inlet of the water vapor channel and the circulating water medium entering from the heat medium water inlet of the waste heat boiler (4); the condensed water successively generates medium-pressure steam, low-pressure steam and heat medium water; the medium-pressure steam enters the No. 1 steam turbine (5) to generate power, and the work process During the process, part of the steam is extracted to supply industrial users. After the medium-pressure steam generates power in the No. 1 steam turbine (5), it forms water, which is discharged through the drain outlet and condensed by the No. 1 condenser (6) before entering the water tank (30). The water in the water tank (30) enters the waste heat boiler (4) through the first condensate inlet and the second condensate inlet in the waste heat boiler (4) to realize circulation; the low-pressure steam enters the thermal power pipe network (8) to exchange heat with the tap water from the hot water preparation station (9), and is sent to the water tank (30) after the heat exchange is completed; the heat medium water enters the hot water preparation station (9) to exchange heat with the tap water, and after the heat exchange is completed, the heat medium water re-enters the waste heat boiler (4) through the No. 1 hot water pump (10) for heat exchange; the tap water is used as domestic hot water after it is successively heat-exchanged with the heat medium water and the low-pressure steam; 2) The flue gas discharged from the waste heat boiler (4) is cooled by the first cooler (11) and then enters the absorption tower (12), where it reacts with the lean amine liquid. The top of the absorption tower (12) discharges clean flue gas, and the bottom of the absorption tower (12) flows out rich amine liquid. The rich amine liquid flowing out of the absorption tower (12) is pressurized by the rich amine liquid pump (13), and then enters the amine liquid heat exchanger (14) to exchange heat with the lean amine liquid from the desorption tower (15). The heated rich amine liquid enters the desorption tower (15) from the first inlet of the rich amine liquid. The lean amine liquid from the desorption tower (15) is cooled by the second cooler (16) after the heat exchange and enters the absorption tower (12); carbon dioxide is decomposed from the rich amine liquid in the desorption tower (15), and the carbon dioxide is discharged from the carbon dioxide outlet of the desorption tower (15) and enters the compression module (25). After being compressed and cooled by the compression module (25), compressed carbon dioxide is obtained; the heat in the desorption tower (15) is provided by the solar heat exchanger (17) and / or the steam heat exchanger (7); the heat provided by the solar heat exchanger (17) is specifically The method refers to the rich amine liquid in the desorption tower (15) flowing out from the rich amine liquid outlet and entering the solar heat exchanger (17) through the solution regulating valve for heat exchange, and then flowing back to the desorption tower (15) from the second inlet of the rich amine liquid; the heat provided by the steam heat exchanger (7) refers to the rich amine liquid in the desorption tower (15) flowing out from the rich amine liquid outlet and entering the steam heat exchanger (7) through the solution regulating valve for heat exchange with the low-pressure steam in the steam heat exchanger (7), and then flowing back to the desorption tower (15) from the second inlet of the rich amine liquid; the low-pressure steam in the steam heat exchanger enters the thermal network (8) after heat exchange; the heat required by the desorption tower (15) is first provided by the solar heat exchanger (17), and when the heat provided by the solar heat exchanger (17) is insufficient, the steam heat exchanger (7) supplements the heat; 3) The rich amine liquid flows out from the rich amine liquid outlet and is regulated by the solution regulating valve to enter the solar heat exchanger (17) for heat exchange, which means that the rich amine liquid exchanges heat with the steam of the circulating water medium in the solar heat exchanger (17). After the heat exchange, the circulating water medium is cooled by the second condenser (18) and pressurized by the second hot water pump (19) before entering the heat storage medium heat exchanger (20). The circulating water medium exchanges heat with the high-temperature heat storage medium in the heat storage medium heat exchanger (20). The circulating water medium is heated to steam, which enters the second steam turbine (21) to generate power. The steam at the outlet of the second steam turbine (21) enters the solar heat exchanger (17) for heat exchange with the rich amine liquid. The high-temperature heat storage medium in the After heat exchange in the heat storage medium heat exchanger (20), a low-temperature heat storage medium is formed, and the low-temperature heat storage medium enters the heat storage medium cold tank (22) for storage; the high-temperature heat storage medium comes from the heat storage medium hot tank (24), and is formed by the parabolic trough solar collector (23) using a linear focusing mechanism to heat the low-temperature heat storage medium from the heat storage medium cold tank (22); the No. 2 steam turbine (21) performs work to generate electricity, and the generated electricity is used for the rich amine liquid pump (13), the No. 2 hot water pump (19) and the compression module (25), and the remaining electricity is determined whether to be connected to the grid according to load changes. When the solar-P2G coupled carbon capture power plant combined system has excess electricity that cannot be absorbed, the P2G technology is used to store energy; 4) In the P2G subsystem, after the carbon dioxide enters the compression module (25), part of the carbon dioxide is mixed with the hydrogen from the water electrolysis device (29) in the gas mixer (26) through the gas regulating valve, and then enters the heat exchanger (27) to exchange heat with the methane from the methanation device (28). The mixed gas after heat exchange enters the methanation device (28) to react and obtain methane; the methane that has completed heat exchange in the heat exchanger (27) enters the storage device; the water electrolysis device (29) generates hydrogen and oxygen through electrolysis.

5. The method for operating the solar-P2G coupled carbon capture power plant combined system according to claim 4, characterized in that: The circulating medium for adsorbing carbon dioxide in the lean amine solution and the rich amine solution is an alcoholamine solution, including an ethanolamine solution and an N-methyldiethanolamine solution; The working pressure of the absorption tower (12) is 100-120 kPa, the outlet pressure of the rich amine liquid pump (13) is 200-220 kPa, and the working pressure of the desorption tower (15) is 200-220 kPa; the working temperature of the solar heat exchanger (17) and the steam heat exchanger (7) is 135-170°C.

6. The method for operating the solar-P2G coupled carbon capture power plant combined system according to claim 4, characterized in that: In step 3), the heat storage medium includes heat transfer oil or molten salt; the working temperature of the heat storage medium is 200-400° C.; The parabolic trough solar collector consists of four parts: a parabolic reflector, a heat collection assembly, a support structure, and a drive structure. It is composed of multiple solar heat collection tubes connected in series and then in parallel. The operating temperature of the circulating water medium in step 3) is 120-350°C.

7. The method for operating the solar-P2G coupled carbon capture power plant combined system according to claim 4, characterized in that: The water electrolysis device in the P2G subsystem includes a PEM electrolyzer, an alkaline electrolyzer and an AEM electrolyzer; The operating temperature of the methanation device is 350-380°C and the operating pressure is 3-3.5MPa; The heat exchanger in the P2G subsystem preheats the mixed gas to 300-320°C, and the working pressure is 3-3.1 MPa.

8. The method for operating the solar-P2G coupled carbon capture power plant combined system according to claim 4, characterized in that: When the combined cycle power plant subsystem is running stably, when the solar radiation intensity suddenly drops, the heat collected by the solar collector decreases accordingly. At this time, the flow rate of the heat storage medium entering the solar collector is reduced to keep the outlet temperature of the heat storage medium of the solar collector unchanged. When the solar radiation intensity suddenly increases, the heat collected by the solar collector increases accordingly. At this time, the flow rate of the heat storage medium entering the solar collector is increased to keep the outlet temperature of the heat storage medium of the solar collector unchanged; when the liquid level of the heat storage medium in the hot tank is low, the outlet flow rate of the heat storage medium in the hot tank is reduced, the solution regulating valve opening of the solar heat exchanger is reduced or closed, the flow rate of the alcohol amine solution entering the solar heat exchanger is reduced, the solution regulating valve opening of the steam heat exchanger is increased, and part of the low-pressure steam at the outlet of the waste heat boiler is extracted to heat the steam heat exchanger. The adjustment target is to reduce the heat exchange rate between solar heat and alcohol amine solution, increase the heat exchange rate between low-pressure steam and alcohol amine solution, and ensure the stable operation of the carbon capture system; When the heat storage capacity of the solar thermal subsystem is sufficient and the load of the carbon capture power plant combined system coupled with solar energy-P2G increases, the flue gas flow rate at the flue gas outlet of the waste heat boiler increases, and the flow rate of the amine supplementary liquid is increased by opening the amine supplementary liquid regulating valve, and the heat storage medium flow entering the heat storage medium heat exchanger is increased, so that the power generation of the No. 2 steam turbine is increased, and the load of the solar heat exchanger increases accordingly to ensure the capture rate of carbon dioxide in the flue gas; when the heat storage capacity of the solar thermal subsystem is sufficient and the load of the carbon capture power plant combined system coupled with solar energy-P2G decreases, the flue gas flow rate at the flue gas outlet of the waste heat boiler decreases, and the heat storage medium flow entering the heat storage medium heat exchanger is reduced, so that the power generation of the No. 2 steam turbine is reduced, and the load of the solar heat exchanger is reduced accordingly to ensure the capture rate of carbon dioxide in the flue gas; when the heat storage capacity of the solar thermal subsystem is insufficient and the load of the carbon capture power plant combined system coupled with solar energy-P2G decreases, the flue gas flow rate at the flue gas outlet of the waste heat boiler decreases, and the heat storage medium flow entering the heat storage medium heat exchanger is reduced, so that the power generation of the No. 2 steam turbine is reduced, and the load of the solar heat exchanger is reduced accordingly to ensure the capture rate of carbon dioxide in the flue gas; When the load of the carbon capture power plant combined system increases, the flue gas flow at the flue gas outlet of the waste heat boiler increases. By opening the amine supplementary liquid regulating valve to increase the flow of amine supplementary liquid, opening the solution regulating valve of the steam heat exchanger to increase the solution flow entering the steam heat exchanger to ensure the capture rate of carbon dioxide in the flue gas; when the heat storage capacity of the solar thermal subsystem is insufficient and the load of the carbon capture power plant combined system coupled with solar energy and P2G decreases, the flue gas flow at the flue gas outlet of the waste heat boiler decreases, opening the solution regulating valve of the steam heat exchanger to reduce the solution flow entering the steam heat exchanger to ensure the capture rate of carbon dioxide in the flue gas; the water electrolysis device in the P2G system absorbs excess system electricity, electrolyzes hydrogen and oxygen, and the hydrogen reacts with part of the captured carbon dioxide in the methanation device to prepare methane, which is input into the natural gas storage tank to maintain safe and stable operation of the system.

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