Coal-based supercritical CO2 power generation cycle and compressed CO2 energy storage coupled system and operation method

Abstract

The invention provides a coal-based supercritical CO2 power generation circulation and compressed CO2 energy storage coupled system and an operation method. The coal-based supercritical CO2 power generation circulation and compressed CO2 energy storage coupled system comprises a coal-based S-CO2 power generation circulation system, a compressed CO2 energy storage circulation system, a fused salt heat storage loop system and a heat storage water loop system. According to the system, S-CO2 is used as a thermal power generation cycle working medium driven by fire coal, and a compressed CO2 energy storage system is coupled, so that the load adjusting requirement of a power grid is met. In the electricity utilization trough period, part of high-temperature and high-pressure CO2 at an outlet of the boiler stores heat energy into the molten salt tank and the hot water tank, and low-temperature CO2 is stored in the high-pressure tank. In the peak period of power utilization, except for coal-fired driving of S-CO2 for power generation, CO2 in the high-pressure tank enters the turbine to do work for power generation after absorbing stored heat energy, and the load response capacity of the system to a power grid is greatly improved. Besides, in the energy storage system, a vortex tube and a gas-liquid separator are used, low-pressure CO2 can be stored in a liquid state, and the size of a CO2 storage tank is remarkably reduced.

Description

Technical Field

[0001] The present invention relates to the fields of power engineering and engineering thermophysics, and in particular to a system and an operation method for coupling a coal-based supercritical CO2 power generation cycle with compressed CO2 energy storage. Background Art

[0002] At present, existing thermal power stations are all based on the steam Rankine cycle to achieve the conversion of coal powder combustion heat energy into electrical energy. Due to material limitations, the high-temperature steam temperature of the steam Rankine cycle is difficult to further increase, which makes the improvement of power generation efficiency very limited. In addition, the efficiency of this technology will drop significantly at low loads, and may even cause the boiler to flame out. In comparison, the supercritical CO2 (S-CO2) cycle can achieve higher temperatures, thereby greatly improving the power generation efficiency of the system. At the same time, the S-CO2 power generation system is compact and occupies a small area. However, the S-CO2 power generation system also faces the demand for variable loads, and how to keep the system at a high efficiency under different loads remains to be solved. In addition, considering the excellent thermophysical properties of CO2, compressed CO2 energy storage has received widespread attention from academia and the business community, and can be used for power supply measurement, grid side and load side, thereby solving the mismatch between electricity supply and demand.

[0003] In summary, the defects of the prior art are: (1) Most existing technologies couple the steam Rankine power generation cycle with the compressed CO2 energy storage cycle. Due to the different media used, the two systems cannot be deeply integrated.

[0004] (2) In compressed CO2 energy storage, two storage tanks are required to store high-pressure and low-pressure CO2 respectively. If CO2 is in a supercritical or gaseous state, the volume of the storage tank will be larger. Summary of the invention

[0005] The present invention provides a system that couples a coal-based supercritical CO2 power generation cycle with compressed CO2 energy storage. The system uses S-CO2 as a coal-driven thermal power generation cycle working fluid and is coupled with a compressed CO2 energy storage system to meet the load regulation needs of the power grid. During the off-peak period of electricity consumption, part of the high-temperature and high-pressure CO2 at the boiler outlet will store thermal energy in the molten salt tank and the hot water tank, while the low-temperature CO2 is stored in the high-pressure tank. During peak electricity consumption, in addition to coal-driven S-CO2 power generation, the CO2 in the high-pressure tank will enter the turbine to generate power after absorbing the stored thermal energy, greatly improving the system's load response capability to the power grid.

[0006] In order to achieve the above-mentioned technical features, the purpose of the present invention is achieved as follows: a system in which a coal-based supercritical CO2 power generation cycle is coupled with a compressed CO2 energy storage, comprising a coal-based S-CO2 power generation cycle system, a compressed CO2 energy storage cycle system, a molten salt heat storage loop system and a hot water storage loop system; the coal-based S-CO2 power generation cycle system uses S-CO2 as a coal-driven thermal power generation cycle working fluid; the coal-based S-CO2 power generation cycle system is coupled with a compressed CO2 energy storage cycle system to meet the load regulation requirements of the power grid; during the off-peak period of electricity consumption, part of the high-temperature and high-pressure CO2 at the boiler outlet will store thermal energy in the molten salt tank of the molten salt heat storage loop system and the hot water tank of the hot water storage loop system, while the low-temperature CO2 is stored in the high-pressure tank; during the peak period of electricity consumption, in addition to coal-driven S-CO2 power generation, the CO2 in the high-pressure tank of the compressed CO2 energy storage cycle system will enter the turbine to generate power after absorbing the stored thermal energy.

[0007] The coal-based S-CO2 power generation cycle system comprises a first plug valve, a first check valve, a second plug valve, a first compressor, a third plug valve and a first three-way valve connected in sequence; one outlet of the first three-way valve is connected to the second three-way valve through a fourth plug valve, a low-temperature regenerator and a fifth plug valve, and the other outlet is connected to the second three-way valve through a sixth plug valve, an economizer and a seventh plug valve; The second three-way valve is connected in sequence to the eighth plug valve, the high-temperature regenerator, the ninth plug valve, the boiler furnace, the tenth plug valve, the low-temperature superheater, the eleventh plug valve, the high-temperature superheater, the twelfth plug valve and the third three-way valve; One of the outlets of the third three-way valve is connected to the compressed CO2 energy storage circulation system through the twenty-second plug valve, and the other outlet is connected to the high-pressure turbine through the thirteenth plug valve, the fourth three-way valve and the fourteenth plug valve to perform work.

[0008] The high-pressure turbine outlet is connected to the boiler furnace through the fifteenth plug valve, and then connected to the low-temperature reheater, the sixteenth plug valve and the high-temperature reheater in sequence. The high-temperature reheater is connected to the low-pressure turbine through the seventeenth plug valve and performs work; The outlet of the low-pressure turbine is connected to the first cooler through the eighteenth plug valve, the high-temperature regenerator, the nineteenth plug valve, the low-temperature regenerator, the twentieth plug valve; The first cooler is connected to the fifth three-way valve through the twenty-first stopcock; one of the outlets of the fifth three-way valve is connected to the compressed CO2 energy storage circulation system through the thirty-second stopcock, and the other outlet is reconnected to the first stopcock.

[0009] The compressed CO2 energy storage cycle system includes a low-pressure CO2 storage tank, which is connected to the second plug valve of the coal-based S-CO2 power generation cycle system through a thirty-fourth plug valve; The CO2 participating in the energy storage cycle passes through the 22nd plug valve after being diverted by the third three-way valve, and then sequentially connects to the molten salt cooler, the 23rd plug valve, the high-temperature water cooler, the 24th plug valve and the low-temperature water cooler for cooling. The low-temperature water cooler then passes through the 25th plug valve, the second one-way valve and the 26th plug valve and is connected to the high-pressure CO2 storage tank; The high-pressure CO2 storage tank is connected to the fourth three-way valve of the coal-based S-CO2 power generation circulation system through the twenty-seventh plug valve, the second compressor, the twenty-eighth plug valve, the low-temperature water heater, the twenty-ninth plug valve, the high-temperature water heater, the thirtieth plug valve, the molten salt heater and the thirty-first plug valve in sequence; After the first cooler, the CO2 participating in the energy storage cycle is diverted by the fifth three-way valve, passes through the thirty-second stopcock, the third one-way valve and the thirty-third stopcock, and is finally stored in a low-pressure CO2 storage tank.

[0010] During energy storage, CO2 at the outlet of the low-temperature regenerator passes through the thirty-seventh stopcock and is connected to the first cooler, and the first cooler is connected to the seventh three-way valve through the thirty-eighth stopcock; one of the outlets of the seventh three-way valve passes through the fourth check valve, the ninth three-way valve, the forty-eighth stopcock, the fifth compressor, the forty-ninth stopcock and the sixth three-way valve, and the sixth three-way valve is connected to the coal-based S-CO2 power generation cycle system through the first three-way valve, and one of the outlets of the seventh three-way valve passes through the thirty-ninth stopcock, the eighth three-way valve, and the fortieth stopcock to be connected to the vortex tube; The hot fluid end in the vortex tube is connected in sequence to the 44th plug valve, the second cooler, the 45th plug valve, the fourth compressor, the 46th plug valve, the 9th three-way valve, the 48th plug valve and the fifth compressor, and the fifth compressor is connected to the coal-based S-CO2 power generation cycle system through the 49th plug valve, the 6th three-way valve and the first three-way valve; The cold fluid end in the vortex tube is connected in sequence to the 41st plug valve, the gas-liquid separator, the 32nd plug valve, the third check valve, the 33rd plug valve and the low-pressure CO2 storage tank; The gaseous CO2 outlet of the gas-liquid separator is connected in sequence to the 42nd stopcock, the third compressor, the 43rd stopcock and the 8th three-way valve; When releasing energy, the low-pressure CO2 storage tank is connected to the coal-based S-CO2 power generation circulation system through the thirty-fourth stopcock, the first pump, the thirty-fifth stopcock, the fourth check valve, the thirty-sixth stopcock, the sixth three-way valve and the first three-way valve.

[0011] The molten salt heat storage loop system comprises a molten salt cold tank, the molten salt cold tank is connected to the second pump through a 50th plug valve, the second pump is connected to the molten salt cooler through a 51st plug valve, and the molten salt cooler is connected to the molten salt hot tank through a 52nd plug valve; The molten salt hot tank is connected to the molten salt cold tank through the fifty-third stopcock, the third pump, the fifty-fourth stopcock, the molten salt heater, the fifty-fifth stopcock and the molten salt cold tank.

[0012] The hot water storage circuit system includes a medium-temperature water tank, which is connected to the high-temperature water tank through a fifty-sixth stopcock, a fourth pump, a fifty-seventh stopcock, a high-temperature water cooler, and a fifty-eighth stopcock; The high temperature water tank is connected to the medium temperature water tank through the fifty-ninth stopcock, the fifth pump, the sixtieth stopcock, the high temperature water heater, and the sixty-first stopcock; The low temperature water tank is connected to the medium temperature water tank through the sixty-second stopcock, the sixth pump, the sixty-third stopcock, the low temperature water cooler, and the sixty-fourth stopcock; The medium-temperature water tank is connected to the low-temperature water tank through the sixty-fifth stopcock, the seventh pump, the sixty-sixth stopcock, the low-temperature water heater, and the sixty-seventh stopcock.

[0013] It also includes a first cooler, the first cooler is connected to a cooling tower, and the outlet of the cooling tower is connected to the inlet of the cooling tower through a sixty-eighth plug valve, an eighth pump, a sixty-ninth plug valve, the first cooler, and a seventyth plug valve; The cold water for the second cooler is provided by the cooling tower. The cooling water passes through the 68th stopcock and is pressurized by the 8th pump. It then enters the second cooler through the 71st stopcock. After cooling is completed, the hot water is discharged to the cooling tower through the 72nd stopcock.

[0014] An operating method of a system coupling a coal-based supercritical CO2 power generation cycle with compressed CO2 energy storage includes three operating modes: Mode 1: During the period of electricity grid parity, the coal-based S-CO2 power generation cycle system operates alone to provide the required electricity.

[0015] Mode 2: During peak electricity consumption periods, the compressed CO2 energy storage cycle system releases the stored energy and works together with the coal-based S-CO2 power generation cycle system to provide the required electricity.

[0016] Mode 3: During periods of low electricity consumption, the coal-based S-CO2 power generation cycle system stores excess energy through a compressed CO2 energy storage cycle system for use during peak electricity consumption periods.

[0017] The specific process of Mode 1 is as follows: In the cycle, CO2 is pressurized and heated by the first compressor, and then divided into two paths at the first three-way valve, one path is heated by the low-temperature regenerator, and the other path is heated by the economizer. The two paths of CO2 are heated to the same temperature and mixed at the second three-way valve; the mixed CO2 is heated by the high-temperature regenerator, and is heated again by passing through the boiler furnace, and then converted into superheated steam by the low-temperature superheater and the high-temperature superheater. The superheated steam is passed through the high-pressure turbine to generate power and cool down; then, the medium-pressure CO2 is heated again by passing through the boiler furnace, and then is heated in multiple stages by the low-temperature reheater and the high-temperature reheater in turn, and then is passed through the low-pressure turbine to generate power, and then the low-pressure CO2 is cooled by the high-temperature regenerator, the low-temperature regenerator and the first cooler in turn; At the same time, cold water for the first cooler is provided by a cooling tower, and the cooling water is pressurized by the eighth pump and flows into the first cooler. After cooling is completed, the hot water is discharged to the cooling tower.

[0018] The specific process of Mode 2 is as follows: The CO2 in the high-pressure CO2 storage tank is pressurized by the second compressor and heated in turn by the low-temperature water heater, the high-temperature water heater, and the molten salt heater, and then mixed with the CO2 heated by the high-temperature superheater at the fourth three-way valve to enter the power generation cycle; after the power generation cycle is completed, the CO2 participating in the energy storage cycle is separated from the power generation cycle at the fifth three-way valve, passes through the third one-way valve 221 and is stored in the low-pressure CO2 storage tank; At the same time, in the molten salt heat storage loop, the molten salt in the molten salt cold tank is pressurized by the second pump, and then is heated in the molten salt cooler and stored in the molten salt hot tank; the molten salt in the molten salt hot tank is pressurized by the third pump, and then is cooled in the molten salt heater and stored in the molten salt cold tank; in the hot water storage loop, the water in the medium-temperature water tank is pressurized by the fourth pump, and then is heated in the high-temperature water cooler and stored in the high-temperature water tank; the water in the high-temperature water tank is pressurized by the fifth pump, and then is cooled in the high-temperature water heater and stored in the medium-temperature water tank; the water in the low-temperature water tank is pressurized by the sixth pump, and then is heated in the low-temperature water cooler and stored in the medium-temperature water tank; the water in the medium-temperature water tank is pressurized by the seventh pump, and then is cooled in the low-temperature water heater and stored in the low-temperature water tank; In addition, if the low-pressure CO2 can be stored in liquid form, after the thermal power generation cycle is completed, the CO2 is divided into two paths at the seventh three-way valve, one path is pressurized by the fifth compressor and enters the power generation cycle, and the other path is divided into cold and hot fluids in the vortex tube. The hot fluid is cooled in the second cooler and pressurized in the fourth compressor, and then pressurized by the fifth compressor to enter the power generation cycle; the cold fluid enters the gas-liquid separator, and the separated liquid CO2 is stored in the low-pressure CO2 storage tank, and the gaseous CO2 is pressurized by the third compressor and re-enters the gas-liquid separator through the vortex tube; At the same time, the cold water for the second cooler is provided by the cooling tower. The cooling water is pressurized by the eighth pump and then flows into the second cooler. After cooling is completed, the hot water is discharged to the cooling tower.

[0019] The specific process of Mode 3 is as follows: The low-pressure CO2 storage tank releases the stored CO2 to provide additional working fluid for the power generation cycle. This part of CO2 is separated from the power generation cycle at the third three-way valve, and is cooled by the molten salt cooler, high-temperature water cooler, and low-temperature water cooler in sequence before being stored in the high-pressure CO2 storage tank. In addition, if you choose to store low-pressure CO2 in liquid form, the CO2 that has completed the previous power generation cycle needs to be pressurized by the fifth compressor, and the liquid CO2 in the low-pressure CO2 storage tank is pressurized by the first pump. After that, the two fluids are mixed at the sixth three-way valve to enter a new round of power generation cycle.

[0020] Beneficial effects of the present invention: 1. The present invention deeply couples compressed CO2 energy storage in the coal-fired S-CO2 power generation system, greatly improving the load regulation capability of the coal-fired power plant.

[0021] 2. The present invention realizes the liquefaction of low-pressure CO2 based on the vortex tube and the separator, and reduces the storage tank volume of the compressed CO2 energy storage system.

[0022] 3. The whole system of the present invention uses CO2 as the working fluid, and the power generation cycle is deeply coupled with the CO2 energy storage cycle. 4. The present invention provides a solution for storing CO2 in a low-pressure liquid state, thereby reducing the storage tank volume of the compressed CO2 energy storage system.

[0023] 5. In the present invention, during the low electricity consumption period, part of the high-temperature and high-pressure CO2 at the boiler outlet will store thermal energy in the molten salt tank and the hot water tank, while the low-temperature CO2 is stored in the high-pressure tank.

[0024] 6. During the peak period of electricity consumption, in addition to coal-fired S-CO2 power generation, the CO2 in the high-pressure tank will enter the turbine to generate power after absorbing the stored heat energy, greatly improving the system's load response capability to the power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0026] Figure 1 The present invention is a thermal power generation system coupled with a compressed CO2 energy storage system.

[0027] Figure 2 This is the layout scheme for storing low-pressure CO2 in liquid form according to the present invention.

[0028] In the figure: 11-first plug valve, 12-first check valve, 13-second plug valve, 14-first compressor, 15-third plug valve, 16-first three-way valve, 17-fourth plug valve, 18-low-temperature regenerator, 19-fifth plug valve, 110-second three-way valve, 111-sixth plug valve, 112-economizer, 113-seventh plug valve, 114-eighth plug valve, 115-high-temperature regenerator, 116-ninth plug valve, 117-boiler furnace, 118-air preheater, 119-tenth plug valve, 120-low-temperature superheater, 121-eleventh plug valve valve, 122-high-temperature superheater, 123-twelfth plug valve, 124-third three-way valve, 125-thirteenth plug valve, 126-fourth three-way valve, 127-fourteenth plug valve, 128-high-pressure turbine, 129-fifteenth plug valve, 130-low-temperature reheater, 131-sixteenth plug valve, 132-high-temperature reheater, 133-seventeenth plug valve, 134-low-pressure turbine, 135-eighteenth plug valve, 136-nineteenth plug valve, 137-twentieth plug valve, 138-first cooler, 139-twenty-first plug valve, 140-fifth three-way valve; 21-22nd plug valve, 22-molten salt cooler, 23-23rd plug valve, 24-high temperature water cooler, 25-24th plug valve, 26-low temperature water cooler, 27-25th plug valve, 28-second check valve, 29-26th plug valve, 210-high pressure CO2 storage tank, 211-27th plug valve, 212-second compressor, 213-28th plug valve, 214-low temperature water heater, 215-29th plug valve, 216-high temperature water heater, 217-30th plug valve, 218-molten salt heater, 219-31st plug valve, 220-32nd plug valve, 221-third check valve, 222-33rd plug valve, 223-low pressure CO2 storage tank, 224-34th plug valve, 225-first pump, 226-30th The fifth plug valve, 227-the fourth one-way valve, 228-the thirty-sixth plug valve, 229-the sixth three-way valve, 230-the thirty-seventh plug valve, 231-the thirty-eighth plug valve, 232-the seventh three-way valve, 233-the thirty-ninth plug valve, 234-the eighth three-way valve, 235-the fortieth plug valve, 236-the vortex tube, 237-the forty-first plug valve, 238-the gas-liquid separator, 239-the forty-second plug valve, 240-the third compressor, 241-the forty-third plug valve, 242-the forty-fourth plug valve, 243-the second cooler, 244-the forty-fifth plug valve, 245-the fourth compressor, 246-the forty-sixth plug valve, 247-the forty-seventh plug valve, 248-the ninth three-way valve, 249-the forty-eighth plug valve, 250-the fifth compressor, 251-the forty-ninth plug valve; 31-molten salt cold tank, 32-50th plug valve, 33-second pump, 34-51st plug valve, 35-52nd plug valve, 36-molten salt hot tank, 37-53rd plug valve, 38-third pump, 39-54th plug valve, 310-55th plug valve, 311-medium temperature water tank, 312-56th plug valve, 313-fourth pump, 314-57th plug valve, 315-58th plug valve, 316-high temperature water tank, 317-59th plug valve, 318-5th pump, 319-60th plug valve Plug valve, 320-61st plug valve, 321-low temperature water tank, 322-62nd plug valve, 323-6th pump, 324-63rd plug valve, 325-64th plug valve, 326-65th plug valve, 327-7th pump, 328-66th plug valve, 329-67th plug valve, 330-68th plug valve, 331-8th pump, 332-69th plug valve, 333-70th plug valve, 334-cooling tower, 335-71st plug valve, 336-72nd plug valve DETAILED DESCRIPTION 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.

[0029] Embodiment 1: See also Figure 1-2, a system coupled with a coal-based supercritical CO2 power generation cycle and compressed CO2 energy storage, including a coal-based S-CO2 power generation cycle system, a compressed CO2 energy storage cycle system, a molten salt heat storage loop system and a hot water storage loop system; the coal-based S-CO2 power generation cycle system uses S-CO2 as a coal-fired thermal power generation cycle working fluid; the coal-based S-CO2 power generation cycle system is coupled with a compressed CO2 energy storage cycle system to meet the load regulation requirements of the power grid; during the off-peak period of electricity consumption, part of the high-temperature and high-pressure CO2 at the boiler outlet will store heat energy in the molten salt tank of the molten salt heat storage loop system and the hot water tank of the hot water storage loop system, while the low-temperature CO2 is stored in the high-pressure tank; during the peak period of electricity consumption, in addition to coal-fired S-CO2 power generation, the CO2 in the high-pressure tank of the compressed CO2 energy storage cycle system will enter the turbine to generate power after absorbing the stored heat energy. By adopting the above-mentioned coupled system, S-CO2 is used as a coal-fired thermal power generation cycle working fluid, and the compressed CO2 energy storage system is coupled to meet the load regulation requirements of the power grid. During the low electricity consumption period, part of the high-temperature and high-pressure CO2 at the boiler outlet will store heat energy in the molten salt tank and the hot water tank, while the low-temperature CO2 will be stored in the high-pressure tank. During the peak electricity consumption period, in addition to coal-fired S-CO2 power generation, the CO2 in the high-pressure tank will enter the turbine to generate power after absorbing the stored heat energy, greatly improving the system's load response capability to the power grid. In addition, in the energy storage system, the present invention uses a vortex tube and a gas-liquid separator to achieve liquid storage of low-pressure CO2, thereby significantly reducing the volume of the CO2 storage tank.

[0030] Embodiment 2: Furthermore, the coal-based S-CO2 power generation cycle system includes a first plug valve 11, a first check valve 12, a second plug valve 13, a first compressor 14, a third plug valve 15 and a first three-way valve 16 connected in sequence; one outlet of the first three-way valve 16 is connected to the second three-way valve 110 through a fourth plug valve 17, a low-temperature regenerator 18, and a fifth plug valve 19, and the other outlet is connected to the second three-way valve 110 through a sixth plug valve 111, an economizer 112 and a seventh plug valve 113; the second three-way valve 110 is connected in sequence The eighth plug valve 114, the high-temperature regenerator 115, the ninth plug valve 116, the boiler furnace 117, the tenth plug valve 119, the low-temperature superheater 120, the eleventh plug valve 121, the high-temperature superheater 122, the twelfth plug valve 123 and the third three-way valve 124; one of the outlets of the third three-way valve 124 is connected to the compressed CO2 energy storage circulation system through the twenty-second plug valve 21, and the other outlet is connected to the high-pressure turbine 128 through the thirteenth plug valve 125, the fourth three-way valve 126 and the fourteenth plug valve 127 and performs work. The outlet of the high-pressure turbine 128 is connected to the boiler furnace 117 through the fifteenth plug valve 129 and then connected to the low-temperature reheater 130, the sixteenth plug valve 131 and the high-temperature reheater 132 in sequence. The high-temperature reheater 132 is connected to the low-pressure turbine 134 through the seventeenth plug valve 133 and performs work; the outlet of the low-pressure turbine 134 is connected to the first cooler 138 through the eighteenth plug valve 135, the high-temperature reheater 115, the nineteenth plug valve 136, the low-temperature reheater 18, the twentieth plug valve 137; the first cooler 138 is connected to the fifth three-way valve 140 through the twenty-first plug valve 139; one of the outlets of the fifth three-way valve 140 is connected to the compressed CO2 energy storage circulation system through the thirty-second plug valve 220, and the other outlet is reconnected to the first plug valve 11.

[0031] By adopting the above-mentioned coal-based S-CO2 power generation cycle system, in the S-CO2 power generation cycle, S-CO2 passes through the first plug valve 11, the first one-way valve 12 and the second plug valve 13, then enters the first compressor 14 for pressurization, and then passes through the third plug valve 15 and is divided into two paths at the first three-way valve 16, one path passes through the fourth plug valve 17, is heated by the low-temperature regenerator 18, and then passes through the fifth plug valve 19; the other path passes through the sixth plug valve 111, is heated by the economizer 112 and passes through the seventh plug valve 113, and the two fluids are mixed at the second three-way valve 110. The mixed CO2 passes through the eighth plug valve 114 and is heated by the high-temperature regenerator 115, then passes through the ninth plug valve 116 and is heated by the boiler furnace 117, then passes through the tenth plug valve 119, the low-temperature superheater 120, the eleventh plug valve 121 and the high-temperature superheater 122 to be converted into superheated steam, then passes through the twelfth plug valve 123 and is divided into two paths at the third three-way valve 124, one path passes through the twenty-second plug valve 21, which is part of the CO2 energy storage cycle, and the other path passes through the thirteenth plug valve 125, the fourth three-way valve 126 and the fourteenth plug valve 127, and then passes through the high-pressure turbine 128 to do work. Then, the medium-pressure CO2 passes through the fifteenth plug valve 129 and is heated again by the boiler furnace 117, then passes through the low-temperature reheater 130, the sixteenth plug valve 131 and the high-temperature reheater 132 to increase temperature, then flows through the seventeenth plug valve 133 and passes through the low-pressure turbine 134 to do work. Afterwards, the low-pressure CO2 is cooled down in sequence through the 18th stopcock 135, the high-temperature regenerator 115, the 19th stopcock 136, the low-temperature regenerator 18, the 20th stopcock 137 and the first cooler 138. The cooled CO2 passes through the 21st stopcock 139 and is divided into two paths at the fifth three-way valve 140, one path passes through the 32nd stopcock 220 and is part of the CO2 energy storage cycle, and the other path passes through the first stopcock 11 and re-enters the thermal power generation cycle.

[0032] Embodiment 3: Furthermore, the compressed CO2 energy storage cycle system includes a low-pressure CO2 storage tank 223, which is connected to the second plug valve 13 of the coal-based S-CO2 power generation cycle system through the thirty-fourth plug valve 224; the CO2 participating in the energy storage cycle passes through the twenty-second plug valve 21 after being diverted by the third three-way valve 124, and then sequentially connects to the molten salt cooler 22, the twenty-third plug valve 23, the high-temperature water cooler 24, the twenty-fourth plug valve 25 and the low-temperature water cooler 26 for cooling, and the low-temperature water cooler 26 then passes through the twenty-fifth plug valve 27, the second one-way valve 28 and the twenty-sixth plug valve 29 and is connected to the high-pressure CO2 storage tank 210 The high-pressure CO2 storage tank 210 is connected to the fourth three-way valve 126 of the coal-based S-CO2 power generation cycle system through the twenty-seventh stopcock 211, the second compressor 212, the twenty-eighth stopcock 213, the low-temperature water heater 214, the twenty-ninth stopcock 215, the high-temperature water heater 216, the 30th stopcock 217, the molten salt heater 218 and the thirty-first stopcock 219 in sequence; after the first cooler 138, the CO2 participating in the energy storage cycle is diverted by the fifth three-way valve 140 and then passes through the thirty-second stopcock 220, the third check valve 221 and the thirty-third stopcock 222, and is finally stored in the low-pressure CO2 storage tank 223.During energy storage, CO2 at the outlet of the low-temperature regenerator 18 passes through the thirty-seventh stopcock 230 and is connected to the first cooler 138, and the first cooler 138 is connected to the seventh three-way valve 232 through the thirty-eighth stopcock 231; one of the outlets of the seventh three-way valve 232 passes through the fourth check valve 247, the ninth three-way valve 248, the forty-eighth stopcock 249, the fifth compressor 250, the forty-ninth stopcock 251 and is connected to the sixth three-way valve 229, and the sixth three-way valve 22 9 is connected to the coal-based S-CO2 power generation cycle system through the first three-way valve 16, one of the outlets of the seventh three-way valve 232 is connected to the vortex tube 236 through the thirty-ninth plug valve 233, the eighth three-way valve 234, and the fortieth plug valve 235; the hot fluid end in the vortex tube 236 is connected in sequence to the forty-fourth plug valve 242, the second cooler 243, the forty-fifth plug valve 244, the fourth compressor 245, the forty-sixth plug valve 246, the ninth three-way valve 24 8. The forty-eighth plug valve 249 and the fifth compressor 250, the fifth compressor 250 is connected to the coal-based S-CO2 power generation circulation system through the forty-ninth plug valve 251, the sixth three-way valve 229 and the first three-way valve 16; the cold fluid end in the vortex tube 236 is connected in sequence to the forty-first plug valve 237, the gas-liquid separator 238, the thirty-second plug valve 220, the third one-way valve 221, the thirty-third plug valve 222 and the low-pressure CO2 storage tank 223; the gas-liquid separator The gaseous CO2 outlet of the separator 238 is connected to the forty-second stopcock 239, the third compressor 240, the forty-third stopcock 241 and the eighth three-way valve 234 in sequence; when releasing energy, the low-pressure CO2 storage tank 223 is connected to the coal-based S-CO2 power generation circulation system through the thirty-fourth stopcock 224, the first pump 225, the thirty-fifth stopcock 226, the fourth check valve 227, the thirty-sixth stopcock 228, the sixth three-way valve 229 and the first three-way valve 16.

[0033] Through the above-mentioned compressed CO2 energy storage cycle system, in the CO2 energy storage cycle, when storing energy, the CO2 in the low-pressure CO2 storage tank 223 passes through the thirty-fourth stopcock 224 and then enters the thermal power generation cycle. The CO2 participating in the energy storage cycle passes through the twenty-second stopcock 21 after being diverted by the third three-way valve 124, and then passes through the molten salt cooler 22, the twenty-third stopcock 23, the high-temperature water cooler 24, the twenty-fourth stopcock 25, and the low-temperature water cooler 26 in sequence for cooling, and then passes through the twenty-fifth stopcock 27, the second one-way valve 28 and the twenty-sixth stopcock 29 and then is stored in the high-pressure CO2 storage tank 210; when releasing energy, the CO2 in the high-pressure CO2 storage tank 210 passes through the twenty-seventh stopcock 211 and then enters the second compressor 212 for pressurization, and then in sequence The temperature is raised through the twenty-eighth stopcock 213, the low-temperature water heater 214, the twenty-ninth stopcock 215, the high-temperature water heater 216, the thirtieth stopcock 217, and the molten salt heater 218, and then passes through the thirty-first stopcock 219 and the fourth three-way valve 126 to enter the thermal power generation cycle. After the first cooler 138, the CO2 participating in the energy storage cycle is diverted through the fifth three-way valve 140 and then passes through the thirty-second stopcock 220, the third one-way valve 221 and the thirty-third stopcock 222, and is finally stored in the low-pressure CO2 storage tank 223.

[0034] In order to achieve low pressure liquid storage of CO2, it can be used Figure 2During energy storage, the CO2 at the outlet of the low-temperature regenerator 18 passes through the thirty-seventh stopcock 230 and is cooled by the first cooler 138, then passes through the thirty-eighth stopcock 231 and is divided into two paths at the seventh three-way valve 232. One path passes through the forty-seventh stopcock 247, the ninth three-way valve 248, the forty-eighth stopcock 249, and is pressurized by the fifth compressor 250, then passes through the forty-ninth stopcock 251 and the sixth three-way valve 229, and enters the S-CO2 power generation cycle, and the other path passes through the thirty-ninth stopcock 233, the eighth three-way valve 234, the fortieth stopcock 235, and then is divided into cold and hot fluids in the vortex tube 236. The hot fluid passes through the forty-fourth stopcock 242 and is cooled in the second cooler 243, then passes through the forty-fifth stopcock 244 and It is pressurized in the fourth compressor 245, then passes through the forty-sixth stopcock 246, the ninth three-way valve 248, the forty-eighth stopcock 249, and then is pressurized by the fifth compressor 250, finally passes through the forty-ninth stopcock 251 and the sixth three-way valve 229, and then enters the S-CO2 power generation cycle through the first three-way valve 16; the cold fluid passes through the forty-first stopcock 237 and enters the gas-liquid separator 238, and the separated liquid CO2 directly passes through the thirty-second stopcock 220, the third one-way valve 221, and the thirty-third stopcock 222 to enter the low-pressure CO2 storage tank 223, the gaseous CO2 passes through the forty-second stopcock 239 and is pressurized by the third compressor 240, and then passes through the forty-third stopcock 241 and the eighth three-way valve 234 to re-enter the cycle. When releasing energy, the liquid CO2 in the low-pressure CO2 storage tank 223 passes through the thirty-fourth stopcock 224 and is pressurized by the first pump 225, and then passes through the thirty-fifth stopcock 226, the fourth check valve 227, the thirty-sixth stopcock 228, the sixth three-way valve 229 in sequence, and finally enters the S-CO2 power generation cycle through the first three-way valve 16.

[0035] Embodiment 4: Furthermore, the molten salt heat storage loop system includes a molten salt cold tank 31, which is connected to the second pump 33 through the 50th stopcock 32, the second pump 33 is connected to the molten salt cooler 22 through the 51st stopcock 34, and the molten salt cooler 22 is connected to the molten salt hot tank 36 through the 52nd stopcock 35; the molten salt hot tank 36 is connected to the molten salt cold tank 31 through the 53rd stopcock 37, the third pump 38, the 54th stopcock 39, the molten salt heater 218, the 55th stopcock 310.

[0036] In the molten salt heat storage circuit, the molten salt in the molten salt cold tank 31 passes through the 50th stopcock 32 and is pressurized by the second pump 33, then passes through the 51st stopcock 34 and is heated in the molten salt cooler 22, then flows through the 52nd stopcock 35 and is stored in the molten salt hot tank 36; the molten salt in the molten salt hot tank 36 passes through the 53rd stopcock 37 and is pressurized by the third pump 38, then passes through the 54th stopcock 39 and is cooled in the molten salt heater 218, then flows through the 55th stopcock 310 and is stored in the molten salt cold tank 31.

[0037] Implementation 5: Furthermore, the hot water storage loop system includes a medium-temperature water tank 311, which is connected to a high-temperature water tank 316 via a fifty-sixth stopcock 312, a fourth pump 313, a fifty-seventh stopcock 314, a high-temperature water cooler 24, and a fifty-eighth stopcock 315; the high-temperature water tank 316 is connected to the medium-temperature water tank 311 via a fifty-ninth stopcock 317, a fifth pump 318, a sixtieth stopcock 319, a high-temperature water heater 216, and a sixty-first stopcock 320; the low-temperature water tank 321 is connected to the medium-temperature water tank 311 via a sixty-second stopcock 322, a sixth pump 323, a sixty-third stopcock 324, a low-temperature water cooler 26, and a sixty-fourth stopcock 325; the medium-temperature water tank 311 is connected to the low-temperature water tank 321 via a sixty-fifth stopcock 326, a seventh pump 327, a sixty-sixth stopcock 328, a low-temperature water heater 214, and a sixty-seventh stopcock 329. It also includes a first cooler 138, which is connected to a cooling tower 334, and an outlet of the cooling tower 334 is connected to an inlet of the cooling tower 334 via the sixty-eighth stopcock 330, the eighth pump 331, the sixty-ninth stopcock 332, the first cooler 138, and the seventieth stopcock 333; cold water for the second cooler 243 is provided by the cooling tower 334, and the cooling water passes through the sixty-eighth stopcock 330 and is pressurized by the eighth pump 331, and then enters the second cooler 243 via the seventy-first stopcock 335. After cooling is completed, the hot water is discharged to the cooling tower 334 via the seventy-second stopcock 336.

[0038] In the hot water storage circuit, the water in the medium-temperature water tank 311 passes through the fifty-sixth stopcock 312 and is pressurized by the fourth 313, then passes through the fifty-seventh stopcock 314 and is heated in the high-temperature water cooler 24, then flows through the fifty-eighth stopcock 315 and is stored in the high-temperature water tank 316; the water in the high-temperature water tank 316 passes through the fifty-ninth stopcock 317 and is pressurized by the fifth pump 318, then passes through the sixtieth stopcock 319 and is cooled in the high-temperature water heater 216, then flows through the sixty-first stopcock 320 and is stored in the medium-temperature water tank 311. The water in the low temperature water tank 321 passes through the sixty-second stopcock 322 and is pressurized by the sixth pump 323, then passes through the sixty-third stopcock 324 and is heated in the low temperature water cooler 26, then passes through the sixty-fourth stopcock 325 and is stored in the medium temperature water tank 311; the water in the medium temperature water tank 311 passes through the sixty-fifth stopcock 326 and is pressurized by the seventh pump 327, then passes through the sixty-sixth stopcock 328 and is cooled in the low temperature water heater 214, then passes through the sixty-seventh stopcock 329 and is stored in the low temperature water tank 321. The cold water of the first cooler 138 is provided by the cooling tower 334, the cooling water passes through the sixty-eighth stopcock 330 and is pressurized by the eighth pump 331, then passes through the sixty-ninth stopcock 332 and flows into the first cooler 138, and after cooling, the hot water is discharged to the cooling tower 334 through the seventieth stopcock 333. The cold water of the second cooler 243 is provided by the cooling tower 334. The cooling water passes through the sixty-eighth stopcock 330 and is pressurized by the eighth pump 331. Then, it enters the second cooler 243 through the seventy-first stopcock 335. After cooling is completed, the hot water is discharged to the cooling tower 334 through the seventy-second stopcock 336.

[0039] Embodiment 6: An operating method of a system coupling a coal-based supercritical CO2 power generation cycle with compressed CO2 energy storage includes three operating modes: Mode 1: During the period of electricity grid parity, the coal-based S-CO2 power generation cycle system operates alone to provide the required electricity.

[0040] Mode 2: During peak electricity consumption periods, the compressed CO2 energy storage cycle system releases the stored energy and works together with the coal-based S-CO2 power generation cycle system to provide the required electricity.

[0041] Mode 3: During periods of low electricity consumption, the coal-based S-CO2 power generation cycle system stores excess energy through a compressed CO2 energy storage cycle system for use during peak electricity consumption periods.

[0042] The specific process of Mode 1 is as follows: In the cycle, CO2 is pressurized and heated by the first compressor 14, and then divided into two paths at the first three-way valve 16, one path is heated by the low-temperature reheater 18, and the other path is heated by the economizer 112. The two paths of CO2 are heated to the same temperature and mixed at the second three-way valve 110; the mixed CO2 is heated by the high-temperature reheater 115, and is heated again by the boiler furnace 117, and then converted into superheated steam by the low-temperature superheater 120 and the high-temperature superheater 122. The superheated steam is passed through the high-pressure turbine 128 to generate power and cool down; then, the medium-pressure CO2 is heated again by the boiler furnace 117, and then is heated in multiple stages by the low-temperature reheater 130 and the high-temperature reheater 132 in sequence, and then is passed through the low-pressure turbine 134 to generate power, and then the low-pressure CO2 is cooled by the high-temperature reheater 115, the low-temperature reheater 18 and the first cooler 138 in sequence; At the same time, cold water for the first cooler 138 is provided by the cooling tower 334 . The cooling water is pressurized by the eighth pump 331 and flows into the first cooler 138 . After cooling is completed, the hot water is discharged to the cooling tower 334 .

[0043] The specific process of Mode 2 is as follows: The CO2 in the high-pressure CO2 storage tank 210 is pressurized by the second compressor 212 and heated in turn by the low-temperature water heater 214, the high-temperature water heater 216, and the molten salt heater 218, and then mixed with the CO2 heated by the high-temperature superheater 122 at the fourth three-way valve 126 to enter the power generation cycle; after the power generation cycle is completed, the CO2 participating in the energy storage cycle is separated from the power generation cycle at the fifth three-way valve 140, passes through the third one-way valve 221 and is stored in the low-pressure CO2 storage tank 223; At the same time, in the molten salt heat storage loop, the molten salt in the molten salt cold tank 31 is pressurized by the second pump 33, and then heated in the molten salt cooler 22 and stored in the molten salt hot tank 36; the molten salt in the molten salt hot tank 36 is pressurized by the third pump 38, and then cooled in the molten salt heater 218 and stored in the molten salt cold tank 31; in the hot water storage loop, the water in the medium temperature water tank 311 is pressurized by the fourth pump 313, and then heated in the high temperature water cooler 24 and stored in the high temperature water tank 36. The water in the high-temperature water tank 316 is pressurized by the fifth pump 318, then cooled in the high-temperature water heater 216 and stored in the medium-temperature water tank 311; the water in the low-temperature water tank 321 is pressurized by the sixth pump 323, then heated in the low-temperature water cooler 26 and stored in the medium-temperature water tank 311; the water in the medium-temperature water tank 311 is pressurized by the seventh pump 327, then cooled in the low-temperature water heater 214 and stored in the low-temperature water tank 321; In addition, if the low-pressure CO2 can be stored in liquid form, after the thermal power generation cycle is completed, the CO2 is divided into two paths at the seventh three-way valve 232, one path is pressurized by the fifth compressor 250 and enters the power generation cycle, and the other path is divided into cold and hot fluids in the vortex tube 236. The hot fluid is cooled in the second cooler 243 and pressurized in the fourth compressor 245, and then pressurized by the fifth compressor 250 to enter the power generation cycle; the cold fluid enters the gas-liquid separator 238, and the separated liquid CO2 is stored in the low-pressure CO2 storage tank 223, and the gaseous CO2 is pressurized by the third compressor 240 and enters the gas-liquid separator 238 again through the vortex tube 236; At the same time, cold water for the second cooler 243 is provided by the cooling tower 334 . The cooling water is pressurized by the eighth pump 331 and then flows into the second cooler 243 . After cooling is completed, the hot water is discharged to the cooling tower 334 .

[0044] The specific process of Mode 3 is as follows: The low-pressure CO2 storage tank 223 releases the stored CO2 to provide additional working fluid for the power generation cycle. This part of CO2 is separated from the power generation cycle at the third three-way valve 124, and is cooled by the molten salt cooler 22, the high-temperature water cooler 24, and the low-temperature water cooler 26 in sequence before being stored in the high-pressure CO2 storage tank 210; In addition, if the low-pressure CO2 is selected to be stored in liquid form, the CO2 that has completed the previous power generation cycle needs to be pressurized by the fifth compressor 250, and the liquid CO2 in the low-pressure CO2 storage tank 223 is pressurized by the first pump 225. After that, the two fluids are mixed at the sixth three-way valve 229 and enter a new round of power generation cycle.

[0045] 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 system for coupling a coal-based supercritical CO2 power generation cycle with compressed CO2 energy storage, characterized in that: It includes a coal-based S-CO2 power generation cycle system, a compressed CO2 energy storage cycle system, a molten salt heat storage loop system and a hot water storage loop system; the coal-based S-CO2 power generation cycle system uses S-CO2 as a coal-fired driven thermal power generation cycle working fluid; the coal-based S-CO2 power generation cycle system is coupled with a compressed CO2 energy storage cycle system to meet the load regulation needs of the power grid; during the off-peak period of electricity consumption, part of the high-temperature and high-pressure CO2 at the boiler outlet will store thermal energy in the molten salt tank of the molten salt heat storage loop system and the hot water tank of the hot water storage loop system, while the low-temperature CO2 is stored in the high-pressure tank; during the peak period of electricity consumption, in addition to coal-fired driven S-CO2 power generation, the CO2 in the high-pressure tank of the compressed CO2 energy storage cycle system will enter the turbine to generate power after absorbing the stored heat energy.

2. According to claim 1, a system for coupling a coal-based supercritical CO2 power generation cycle with compressed CO2 energy storage is characterized in that: The coal-based S-CO2 power generation cycle system comprises a first plug valve (11), a first non-return valve (12), a second plug valve (13), a first compressor (14), a third plug valve (15) and a first three-way valve (16) which are connected in sequence; one outlet of the first three-way valve (16) is connected to the second three-way valve (110) via a fourth plug valve (17), a low-temperature regenerator (18) and a fifth plug valve (19), and the other outlet is connected to the second three-way valve (110) via a sixth plug valve (111), an economizer (112) and a seventh plug valve (113); The second three-way valve (110) is connected in sequence to the eighth plug valve (114), the high-temperature regenerator (115), the ninth plug valve (116), the boiler furnace (117), the tenth plug valve (119), the low-temperature superheater (120), the eleventh plug valve (121), the high-temperature superheater (122), the twelfth plug valve (123) and the third three-way valve (124); One of the outlets of the third three-way valve (124) is connected to the compressed CO2 energy storage circulation system through the twenty-second plug valve (21), and the other outlet is connected to the high-pressure turbine (128) through the thirteenth plug valve (125), the fourth three-way valve (126) and the fourteenth plug valve (127) to perform work.

3. According to claim 2, a system for coupling a coal-based supercritical CO2 power generation cycle with compressed CO2 energy storage is characterized in that: The outlet of the high-pressure turbine (128) is connected to the boiler furnace (117) through a fifteenth plug valve (129), and then connected in sequence to a low-temperature reheater (130), a sixteenth plug valve (131), and a high-temperature reheater (132). The high-temperature reheater (132) is connected to a low-pressure turbine (134) through a seventeenth plug valve (133) and performs work. The outlet of the low-pressure turbine (134) is connected to the first cooler (138) via an eighteenth stopcock (135), a high-temperature regenerator (115), a nineteenth stopcock (136), a low-temperature regenerator (18), a twentieth stopcock (137); The first cooler (138) is connected to the fifth three-way valve (140) via the twenty-first stopcock (139); one of the outlets of the fifth three-way valve (140) is connected to the compressed CO2 energy storage circulation system via the thirty-second stopcock (220), and the other outlet is reconnected to the first stopcock (11).

4. According to claim 3, a system for coupling a coal-based supercritical CO2 power generation cycle with compressed CO2 energy storage is characterized in that: The compressed CO2 energy storage circulation system comprises a low-pressure CO2 storage tank (223), and the low-pressure CO2 storage tank (223) is connected to the second plug valve (13) of the coal-based S-CO2 power generation circulation system via a thirty-fourth plug valve (224); The CO2 participating in the energy storage cycle is diverted by the third three-way valve (124) and then passes through the twenty-second plug valve (21), and then sequentially connects to the molten salt cooler (22), the twenty-third plug valve (23), the high-temperature water cooler (24), the twenty-fourth plug valve (25) and the low-temperature water cooler (26) to reduce the temperature. The low-temperature water cooler (26) then passes through the twenty-fifth plug valve (27), the second one-way valve (28) and the twenty-sixth plug valve (29) and is connected to the high-pressure CO2 storage tank (210); The high-pressure CO2 storage tank (210) is connected to the fourth three-way valve (126) of the coal-based S-CO2 power generation cycle system via the twenty-seventh plug valve (211), the second compressor (212), the twenty-eighth plug valve (213), the low-temperature water heater (214), the twenty-ninth plug valve (215), the high-temperature water heater (216), the thirtieth plug valve (217), the molten salt heater (218) and the thirty-first plug valve (219) in sequence; After the first cooler (138), the CO2 participating in the energy storage cycle is diverted by the fifth three-way valve (140) and passes through the thirty-second stopcock (220), the third one-way valve (221) and the thirty-third stopcock (222), and is finally stored in the low-pressure CO2 storage tank (223).

5. A system of coupling a coal-based supercritical CO2 power generation cycle with compressed CO2 energy storage according to claim 4, characterized in that: During energy storage, CO2 at the outlet of the low-temperature regenerator (18) passes through the thirty-seventh stopcock (230) and is connected to the first cooler (138), and the first cooler (138) is connected to the seventh three-way valve (232) through the thirty-eighth stopcock (231); one of the outlets of the seventh three-way valve (232) passes through the fourth check valve (247), the ninth three-way valve (248), the forty-eighth stopcock (249), the fifth compressor (250), the forty-ninth stopcock (251) and is connected to the sixth three-way valve (229), and the sixth three-way valve (229) is connected to the coal-based S-CO2 power generation cycle system through the first three-way valve (16); one of the outlets of the seventh three-way valve (232) passes through the thirty-ninth stopcock (233), the eighth three-way valve (234) and the fortieth stopcock (235) and is connected to the vortex tube (236); The hot fluid end in the vortex tube (236) is connected in sequence to the forty-fourth plug valve (242), the second cooler (243), the forty-fifth plug valve (244), the fourth compressor (245), the forty-sixth plug valve (246), the ninth three-way valve (248), the forty-eighth plug valve (249) and the fifth compressor (250); the fifth compressor (250) is connected to the coal-based S-CO2 power generation cycle system via the forty-ninth plug valve (251), the sixth three-way valve (229) and the first three-way valve (16); The cold fluid end in the vortex tube (236) is connected in sequence to the forty-first plug valve (237), the gas-liquid separator (238), the thirty-second plug valve (220), the third one-way valve (221), the thirty-third plug valve (222) and the low-pressure CO2 storage tank (223); The gaseous CO2 outlet of the gas-liquid separator (238) is connected to the forty-second stopcock (239), the third compressor (240), the forty-third stopcock (241) and the eighth three-way valve (234) in sequence; When releasing energy, the low-pressure CO2 storage tank (223) is connected to the coal-based S-CO2 power generation circulation system through the thirty-fourth stopcock (224), the first pump (225), the thirty-fifth stopcock (226), the fourth one-way valve (227), the thirty-sixth stopcock (228), the sixth three-way valve (229) and the first three-way valve (16).

6. A system of coupling a coal-based supercritical CO2 power generation cycle with compressed CO2 energy storage according to claim 5, characterized in that: The molten salt heat storage loop system comprises a molten salt cold tank (31), the molten salt cold tank (31) is connected to a second pump (33) via a 50th plug valve (32), the second pump (33) is connected to a molten salt cooler (22) via a 51st plug valve (34), and the molten salt cooler (22) is connected to a molten salt hot tank (36) via a 52nd plug valve (35); The molten salt hot tank (36) is connected to the molten salt cold tank (31) via the fifty-third stopcock (37), the third pump (38), the fifty-fourth stopcock (39), the molten salt heater (218), the fifty-fifth stopcock (310).

7. A system of coupling a coal-based supercritical CO2 power generation cycle with compressed CO2 energy storage according to claim 6, characterized in that: The hot water storage circuit system comprises a medium-temperature water tank (311), and the medium-temperature water tank (311) is connected to the high-temperature water tank (316) via a fifty-sixth stopcock (312), a fourth pump (313), a fifty-seventh stopcock (314), a high-temperature water cooler (24), and a fifty-eighth stopcock (315); The high-temperature water tank (316) is connected to the medium-temperature water tank (311) via a fifty-ninth stopcock (317), a fifth pump (318), a sixtieth stopcock (319), a high-temperature water heater (216), and a sixty-first stopcock (320); The low-temperature water tank (321) is connected to the medium-temperature water tank (311) via a sixty-second stopcock (322), a sixth pump (323), a sixty-third stopcock (324), a low-temperature water cooler (26), and a sixty-fourth stopcock (325); The medium-temperature water tank (311) is connected to the low-temperature water tank (321) via a sixty-fifth stopcock (326), a seventh pump (327), a sixty-sixth stopcock (328), a low-temperature water heater (214), and a sixty-seventh stopcock (329).

8. A system of coupling a coal-based supercritical CO2 power generation cycle with compressed CO2 energy storage according to claim 7, characterized in that: It also includes a first cooler (138), the first cooler (138) is connected to a cooling tower (334), and the outlet of the cooling tower (334) is connected to the inlet of the cooling tower (334) via a sixty-eighth plug valve (330), an eighth pump (331), a sixty-ninth plug valve (332), the first cooler (138), and a seventyth plug valve (333); The cold water of the second cooler (243) is provided by the cooling tower (334). The cooling water passes through the sixty-eighth stopcock (330) and is pressurized by the eighth pump (331), and then enters the second cooler (243) through the seventy-first stopcock (335). After cooling is completed, the hot water is discharged to the cooling tower (334) through the seventy-second stopcock (336).

9. The method for operating a system of coupling a coal-based supercritical CO2 power generation cycle with compressed CO2 energy storage as described in claim 7, characterized in that: There are three operating modes: Mode 1: During the period of electricity grid parity, the coal-based S-CO2 power generation cycle system operates alone to provide the required electricity. Mode 2: During peak electricity consumption periods, the compressed CO2 energy storage cycle system releases the stored energy and works together with the coal-based S-CO2 power generation cycle system to provide the required electricity. Mode 3: During periods of low electricity consumption, the coal-based S-CO2 power generation cycle system stores excess energy through a compressed CO2 energy storage cycle system for use during peak electricity consumption periods.

10. The method for operating a system of coupling a coal-based supercritical CO2 power generation cycle with compressed CO2 energy storage according to claim 9, characterized in that: The specific process of Mode 1 is as follows: In the cycle, CO2 is pressurized and heated by the first compressor (14), and then divided into two paths at the first three-way valve (16), one path is heated by the low-temperature regenerator (18), and the other path is heated by the economizer (112). The two paths of CO2 are heated to the same temperature and mixed at the second three-way valve (110); the mixed CO2 is heated by the high-temperature regenerator (115), and is heated again by the boiler furnace (117), and then is heated by the low-temperature superheater (120) and the high-temperature superheater (121). (122) converts it into superheated steam, which is then passed through the high-pressure turbine (128) to generate power and cool down; then, the medium-pressure CO2 is heated again by the boiler furnace (117), and then successively passed through the low-temperature reheater (130) and the high-temperature reheater (132) for multi-stage heating, and then passed through the low-pressure turbine (134) to generate power, and then, the low-pressure CO2 is successively cooled by the high-temperature reheater (115), the low-temperature reheater (18) and the first cooler (138); At the same time, cold water for the first cooler (138) is provided by a cooling tower (334). The cooling water is pressurized by the eighth pump (331) and flows into the first cooler (138). After cooling is completed, the hot water is discharged to the cooling tower (334).

11. The method for operating a system of coupling a coal-based supercritical CO2 power generation cycle with compressed CO2 energy storage according to claim 9, characterized in that: The specific process of Mode 2 is as follows: The CO2 in the high-pressure CO2 storage tank (210) is pressurized by the second compressor (212) and then heated in sequence by the low-temperature water heater (214), the high-temperature water heater (216), and the molten salt heater (218), and then mixed with the CO2 heated by the high-temperature superheater (122) at the fourth three-way valve (126) to enter the power generation cycle; after the power generation cycle is completed, the CO2 participating in the energy storage cycle is separated from the power generation cycle at the fifth three-way valve (140), passes through the third one-way valve 221, and is stored in the low-pressure CO2 storage tank (223); At the same time, in the molten salt heat storage loop, the molten salt in the molten salt cold tank (31) is pressurized by the second pump (33), then heated in the molten salt cooler (22) and stored in the molten salt hot tank (36); the molten salt in the molten salt hot tank (36) is pressurized by the third pump (38), then cooled in the molten salt heater (218) and stored in the molten salt cold tank (31); in the hot water storage loop, the water in the medium temperature water tank (311) is pressurized by the fourth pump (313), then heated in the high temperature water cooler (24) and stored in the high temperature water tank (316); the water in the high-temperature water tank (316) is pressurized by the fifth pump (318), then cooled in the high-temperature water heater (216) and stored in the medium-temperature water tank (311); the water in the low-temperature water tank (321) is pressurized by the sixth pump (323), then heated in the low-temperature water cooler (26) and stored in the medium-temperature water tank (311); the water in the medium-temperature water tank (311) is pressurized by the seventh pump (327), then cooled in the low-temperature water heater (214) and stored in the low-temperature water tank (321); In addition, if the low-pressure CO2 can be stored in a liquid state, after the thermal power generation cycle is completed, the CO2 is divided into two paths at the seventh three-way valve (232), one path is pressurized by the fifth compressor (250) and enters the power generation cycle, and the other path is divided into cold and hot fluids in the vortex tube (236), the hot fluid is cooled in the second cooler (243) and pressurized in the fourth compressor (245), and then pressurized by the fifth compressor (250) and enters the power generation cycle; the cold fluid enters the gas-liquid separator (238), and the separated liquid CO2 is stored in the low-pressure CO2 storage tank (223), and the gaseous CO2 is pressurized by the third compressor (240) and enters the gas-liquid separator (238) again through the vortex tube (236); At the same time, cold water for the second cooler (243) is provided by a cooling tower (334). The cooling water is pressurized by an eighth pump (331) and then flows into the second cooler (243). After cooling is completed, the hot water is discharged to the cooling tower (334).

12. The method for operating a system of coupling a coal-based supercritical CO2 power generation cycle with compressed CO2 energy storage according to claim 9, characterized in that: The specific process of Mode 3 is as follows: The low-pressure CO2 storage tank (223) releases the stored CO2 to provide additional working fluid for the power generation cycle. This part of CO2 is separated from the power generation cycle at the third three-way valve (124), and is cooled in sequence by the molten salt cooler (22), the high-temperature water cooler (24), and the low-temperature water cooler (26) before being stored in the high-pressure CO2 storage tank (210); In addition, if it is chosen to enable the low-pressure CO2 to be stored in liquid form, the CO2 that has completed the previous power generation cycle needs to be pressurized by the fifth compressor (250), and the liquid CO2 in the low-pressure CO2 storage tank (223) is pressurized by the first pump (225). After that, the two fluids are mixed at the sixth three-way valve (229) to enter a new round of power generation cycle.

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