Supercritical carbon dioxide coal-fired power generation system integrated with thermal energy storage and operation method

Abstract

The present invention discloses a supercritical carbon dioxide coal-fired power generation system integrated with thermal energy storage and an operation method thereof. The system includes a reheat and recompression power generation system, a thermal energy storage system, and a heat release system. The equipment of the thermal energy storage system and the heat release system is shared, including a high-temperature heat exchanger, a hot thermal energy storage tank, a cold thermal energy storage tank, an auxiliary turbine, and an auxiliary recuperator. During thermal energy storage, the extraction steam before the high-pressure turbine is used to heat the thermal energy storage material, storing the high-temperature heat of the extraction steam while reducing the working fluid flow rates of the high- and low-pressure turbines, thereby reducing the unit load. During heat release, the stored high-temperature heat is used to heat the diverted working fluid from the inlet side of the high-temperature recuperator, and the heated working fluid enters the auxiliary turbine to do work, thereby increasing the unit load. In addition, the auxiliary recuperator also recovers the heat of the working fluid at the outlet of the auxiliary turbine to preheat the diverted working fluid at the inlet side of the high-temperature recuperator, improving the system efficiency. The present invention improves the flexibility of the coal-fired power generation unit, reduces the minimum operating load of the unit, and increases the load change rate by integrating the thermal energy storage cycle and the heat release cycle.

Description

Technical Field

[0001] The present invention belongs to the technical field of power generation, and in particular relates to a supercritical carbon dioxide coal-fired power generation system with integrated heat storage and an operation method thereof. Background Art

[0002] Supercritical carbon dioxide (SCCO) is a highly promising new circulating fluid. Its critical point is close to ambient temperature and its high density enables high power density and compact turbine and heat exchanger equipment. The SCCO power cycle, based on the Brayton cycle principle, achieves energy conversion, offering higher energy conversion efficiency than conventional steam power cycles and holding great potential for application in coal-fired power generation.

[0003] As my country's power system accelerates its transformation, the coal-fired power generation industry faces urgent demands for more efficient and flexible technologies to better serve the peak load regulation needs of renewable energy. One of the flexibility requirements for coal-fired power generation units is the ability to operate with large load variations and ultra-low loads during steady-state conditions, as well as to rapidly increase or decrease loads during transient conditions. Coal-fired power generation systems using supercritical carbon dioxide as a working fluid can improve unit efficiency, but their flexibility is still limited by the boiler's minimum steady-state load and boiler-turbine energy flow coupling, leaving room for improvement. Summary of the Invention

[0004] In order to further improve the flexibility of supercritical carbon dioxide coal-fired power generation units, widen the load variable range, and increase the load variable rate, the present invention proposes a supercritical carbon dioxide coal-fired power generation system with integrated heat storage and an operation method.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A supercritical carbon dioxide coal-fired power generation system with integrated heat storage, comprising a reheat and recompression power generation system, a heat storage system, and a heat release system;

[0007] The reheating and recompression power generation system specifically includes a boiler 1, a high-pressure turbine 2, a low-pressure turbine 3, a recompressor 4, a main compressor 6, a cooler 5, a low-temperature recuperator 7, and a high-temperature recuperator 8; the outlet of the main compressor 6 is sequentially connected to the cold side of the low-temperature recuperator 7 and the cold side of the high-temperature recuperator 8, the outlet of the cold side of the high-temperature recuperator 8 is connected to the boiler 1, the working medium at the outlet of the boiler 1 is connected to the inlet of the high-pressure turbine 2, the working medium at the outlet of the high-pressure turbine 2 is connected to the boiler 1, the reheated working medium at the outlet of the boiler 1 is connected to the inlet of the low-pressure turbine 3, the outlet of the low-pressure turbine 3 is sequentially connected to the hot side of the high-temperature recuperator 8 and the hot side of the low-temperature recuperator 7, the outlet of the hot side of the low-temperature recuperator 7 is respectively connected to the inlet of the recompressor 4 and the inlet of the cooler 5, the outlet of the recompressor 4 and the outlet of the cold side of the low-temperature recuperator 7 are connected to the inlet of the cold side of the high-temperature recuperator 8, and the outlet of the cooler 5 is connected to the inlet of the main compressor 6; there is also a shunt pipeline at the inlet of the cold side of the high-temperature recuperator 8 that is also connected to the inlet of the tail of the boiler 1; the high-temperature heat exchanger 13, the heat storage cold tank 12, the heat storage hot tank 11, and the auxiliary turbine 10 constitute both a heat storage system and a heat release system; when forming the heat storage system, the inlet of the hot side of the high-temperature heat exchanger 13 is connected to the inlet of the high-pressure turbine 2, the outlet of the hot side of the high-temperature heat exchanger 13 is connected to the inlet of the auxiliary turbine 10, and the inlet and outlet of the cold side of the high-temperature heat exchanger 13 are respectively connected to the heat storage cold tank 12 and the heat storage hot tank 11;

[0008] When forming the heat release system, the inlet of the cold side of the high-temperature heat exchanger 13 is connected to the shunt pipeline at the inlet of the cold side of the high-temperature recuperator 8, the outlet of the cold side of the high-temperature heat exchanger 13 is connected to the inlet of the auxiliary turbine 10, and the inlet and outlet of the hot side of the high-temperature heat exchanger 13 are respectively connected to the heat storage hot tank 11 and the heat storage cold tank 12;

[0009] A first valve 141 is provided on the connecting pipeline between the boiler 1 and the inlet of the high-pressure turbine 2, a second valve 142 is provided on the connecting pipeline between the high-temperature heat exchanger 13 and the inlet of the high-pressure turbine 2, and a third valve 143 is provided on the connecting pipeline between the high-temperature heat exchanger 13 and the shunt at the inlet of the cold side of the high-temperature recuperator 8.

[0010] It also includes an auxiliary recuperator 9; during heat storage, the inlet and outlet of the hot side of the auxiliary recuperator 9 are respectively connected to the outlet of the auxiliary turbine 10 and the inlet of the hot side of the low-temperature recuperator 7, and the inlet and outlet of the cold side of the auxiliary recuperator 9 are respectively connected to the shunt pipeline at the inlet of the cold side of the high-temperature recuperator 8 and the inlet of the tail of the boiler 1; the connection relationship during heat release is the same as that during heat storage.

[0011] The inlet temperature of the main compressor 6 is 32 - 42 °C.

[0012] The inlet pressure of the main compressor 6 is 7.5 - 9.0 MPa.

[0013] The operation method of an integrated heat storage supercritical carbon dioxide coal-fired power generation system includes a conventional operation mode, a heat storage operation mode, and a heat release operation mode:

[0014] In the described normal operation mode, the second valve 142 and the third valve 143 are closed, and the first valve 141 is opened. The high-temperature and high-pressure carbon dioxide working fluid at the outlet of the boiler 1 first enters the high-pressure turbine 2 to do work. After the working fluid at the outlet of the high-pressure turbine 2 is reheated by the boiler 1, it then enters the low-pressure turbine 3 to do work. The working fluid at the outlet of the low-pressure turbine 3 is successively cooled by the high-temperature recuperator 8 and the low-temperature recuperator 7 and then divided into two parts: one part is compressed and boosted by the recompressor 4; the other part is cooled by the cooler 5 and then enters the main compressor 6 to be compressed and boosted. The working fluid at the outlet of the main compressor 6 enters the low-temperature recuperator 7 for heating. After the working fluid at the cold side outlet of the low-temperature recuperator 7 converges with the working fluid at the outlet of the recompressor 4, it is divided again: one part enters the boiler 1 after being heated by the high-temperature recuperator 8; the other part of the working fluid directly enters the tail of the boiler 1 to absorb the heat of the medium and low-temperature flue gas, and the two fluid streams converge in the boiler;

[0015] In the described heat storage operation mode, on the basis of the normal operation mode, the second valve 142 is opened; a part of the working fluid at the inlet of the high-pressure turbine 2 is diverted to heat the heat storage material from the cold heat storage tank 12 in the high-temperature heat exchanger 13. After the heat storage material is heated to a high temperature state, it is stored in the hot heat storage tank 11; by diverting the flow, the working fluid flow rates of the high-pressure turbine 2 and the low-pressure turbine 3 are reduced, and the unit load is quickly reduced;

[0016] In the described heat release operation mode, on the basis of the normal operation mode, the third valve 143 is opened; the system flow rate and the flow rate of the diversion pipeline at the cold side inlet of the high-temperature recuperator 8 are increased to release the high-temperature heat storage material stored in the hot heat storage tank 11, and the carbon dioxide working fluid from the diversion pipeline at the cold side inlet of the high-temperature recuperator 8 is heated in the high-temperature heat exchanger 13. The heated working fluid at the outlet of the high-temperature heat exchanger 13 enters the auxiliary turbine 10 to do work and generate electricity, quickly increasing the unit load.

[0017] In the heat storage operation mode, in order to reduce the pressure of the working fluid at the outlet of the high-temperature heat exchanger 13, the carbon dioxide working fluid at the outlet of the high-temperature heat exchanger 13 enters the auxiliary turbine 10 to expand and do work. After the working fluid at the outlet of the auxiliary turbine 10 heats the diverted working fluid from the cold side inlet of the high-temperature recuperator 8 in the auxiliary recuperator 9, it converges into the hot side inlet of the low-temperature recuperator 7.

[0018] In the heat release operation mode, the working fluid at the outlet of the auxiliary turbine 10 releases heat in the auxiliary recuperator 9, heating the diverted working fluid from the cold side inlet of the high-temperature recuperator 8, and finally converging into the hot side inlet of the low-temperature recuperator 7.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] 1) The present invention reduces the turbine flow rate by extracting steam to achieve rapid load reduction; and realizes rapid load increase through the work of the auxiliary turbine, improving the load change rate of the unit.

[0021] 2) The integrated thermal energy storage system of the present invention can reduce the minimum operating load of a coal-fired power generation unit through air-extraction thermal energy storage, and increase the output power of the unit by releasing heat, thereby broadening the operating load range of the unit and enhancing flexibility.

[0022] 3) The heat storage and heat release cycles of the present invention are similar, and the equipment is universal, which can greatly simplify the structure of the integrated system. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 FIG. is a schematic diagram of a supercritical carbon dioxide coal-fired power generation system with integrated thermal energy storage of the present invention. The solid line is the heat storage cycle, and the dashed line is the heat release cycle.

[0024] FIG. 2(a) is a schematic diagram of the conventional operation mode of a supercritical carbon dioxide coal-fired power generation system;

[0025] FIG. 2(b) is a schematic diagram of the heat storage mode;

[0026] FIG. 2(c) is a schematic diagram of the heat release mode. DETAILED DESCRIPTION OF THE INVENTION

[0027] The present invention will be further described in detail below in conjunction with the drawings and specific embodiments.

[0028] As Figure 1 shown, a supercritical carbon dioxide coal-fired power generation system with integrated thermal energy storage of the present invention includes a reheat and recompression power generation system, a thermal energy storage system and a heat release system:

[0029] The reheat and recompression power generation system specifically includes a boiler 1, a high-pressure turbine 2, a low-pressure turbine 3, a recompressor 4, a main compressor 6, a cooler 5, a low-temperature recuperator 7 and a high-temperature recuperator 8; the outlet of the main compressor 6 is sequentially connected to the cold side of the low-temperature recuperator 7 and the cold side of the high-temperature recuperator 8, the outlet of the cold side of the high-temperature recuperator 8 is connected to the boiler 1, the working medium at the outlet of the boiler 1 is connected to the inlet of the high-pressure turbine 2, the working medium at the outlet of the high-pressure turbine 2 is connected to the boiler 1, the reheated working medium at the outlet of the boiler 1 is connected to the inlet of the low-pressure turbine 3, the outlet of the low-pressure turbine 3 is sequentially connected to the hot side of the high-temperature recuperator 8 and the hot side of the low-temperature recuperator 7, the outlet of the hot side of the low-temperature recuperator 7 is respectively connected to the inlet of the recompressor 4 and the inlet of the cooler 5, the outlet of the recompressor 4 and the outlet of the cold side of the low-temperature recuperator 7 are connected to the inlet of the cold side of the high-temperature recuperator 8, and the outlet of the cooler 5 is connected to the inlet of the main compressor 6; there is also a shunt pipeline at the inlet of the cold side of the high-temperature recuperator 8 that is also connected to the inlet of the tail of the boiler 1.

[0030] The thermal energy storage system specifically includes a high-temperature heat exchanger 13, a cold thermal energy storage tank 12, a hot thermal energy storage tank 11 and an auxiliary turbine 10; the hot side inlet of the high-temperature heat exchanger 13 is connected to the inlet of the high-pressure turbine 2, the hot side outlet of the high-temperature heat exchanger 13 is connected to the inlet of the auxiliary turbine 10, and the cold side inlet and outlet of the high-temperature heat exchanger 13 are respectively connected to the cold thermal energy storage tank 12 and the hot thermal energy storage tank 11.

[0031] The exothermic system specifically includes a high-temperature heat exchanger 13, a heat storage cold tank 12, a heat storage hot tank 11, and an auxiliary turbine 10; the cold-side inlet of the high-temperature heat exchanger 13 is connected to a shunt pipeline at the cold-side inlet of the high-temperature recuperator 8, the cold-side outlet of the high-temperature heat exchanger 13 is connected to the inlet of the auxiliary turbine 10, and the hot-side inlet and outlet of the high-temperature heat exchanger 13 are respectively connected to the heat storage hot tank 11 and the heat storage cold tank 12.

[0032] The system further includes an auxiliary recuperator 9; during heat storage, the inlet and outlet of the hot side of the auxiliary recuperator 9 are respectively connected to the outlet of the auxiliary turbine 10 and the inlet of the hot side of the low-temperature recuperator 7, and the inlet and outlet of the cold side of the auxiliary recuperator 9 are respectively connected to a shunt pipeline at the cold-side inlet of the high-temperature recuperator 8 and the inlet of the tail part of the boiler 1; the connection relationship during heat release is the same as that during heat storage.

[0033] A first valve 141 is provided on the connecting pipeline between the boiler 1 and the inlet of the high-pressure turbine 2, a second valve 142 is provided on the connecting pipeline between the high-temperature heat exchanger 13 and the inlet of the high-pressure turbine 2, and a third valve 143 is provided on the connecting pipeline where the high-temperature heat exchanger 13 is shunted from the inlet of the high-temperature recuperator 8.

[0034] The inlet temperature of the main compressor 6 is 32 - 42 °C.

[0035] The inlet pressure of the main compressor 6 is 7.5 - 9.0 MPa.

[0036] An operation method of an integrated heat storage supercritical carbon dioxide coal-fired power generation system is characterized by including a normal operation mode, a heat storage operation mode, and a heat release operation mode:

[0037] In the normal operation mode, the second valve 142 and the third valve 143 are closed, the first valve 141 is opened, the high-temperature and high-pressure carbon dioxide working medium at the outlet of the boiler 1 first enters the high-pressure turbine 2 to do work, the working medium at the outlet of the high-pressure turbine 2 is reheated by the boiler 1 and then enters the low-pressure turbine 3 to do work, the working medium at the outlet of the low-pressure turbine 3 is successively released heat through the high-temperature recuperator 8 and the low-temperature recuperator 7 and then is divided into two parts: one part is compressed and boosted by the recompressor 4; the other part is cooled by the cooler 5 and then enters the main compressor 6 to be compressed and boosted, the working medium at the outlet of the main compressor 6 enters the low-temperature recuperator 7 for heating, and the working medium at the cold-side outlet of the low-temperature recuperator 7 converges with the working medium at the outlet of the recompressor 4 and then is shunted again: one part enters the boiler 1 after being heated by the high-temperature recuperator 8; the other part of the working medium directly enters the tail part of the boiler 1 to absorb the heat of medium and low-temperature flue gas, and the two fluid streams converge in the boiler, as shown in Figure 2(a);

[0038] In the heat storage operation mode, on the basis of the conventional operation mode, the second valve 142 is further opened; a part of the working medium at the inlet of the high-pressure turbine 2 is diverted to heat the heat storage material from the heat storage cold tank 12 in the high-temperature heat exchanger 13. The heat storage material can be molten salt. After being heated to a high temperature state, the heat storage material is stored in the heat storage hot tank 11; the working medium flow rates of the high-pressure turbine 2 and the low-pressure turbine 3 are reduced by diversion, and the unit load is quickly reduced; in addition, in order to reduce the working medium pressure at the outlet of the high-temperature heat exchanger 13, the carbon dioxide working medium at the outlet of the high-temperature heat exchanger 13 enters the auxiliary turbine 10 to expand and do work. After the working medium at the outlet of the auxiliary turbine 10 heats the diverted working medium from the cold side inlet of the high-temperature recuperator 8 in the auxiliary recuperator 9, it merges into the hot side inlet of the low-temperature recuperator 7, as shown in Fig. 2(b).

[0039] In the heat release operation mode, on the basis of the conventional operation mode, the third valve 143 is opened; the system flow rate and the flow rate of the diversion pipeline at the cold side inlet of the high-temperature recuperator 8 are increased, and the high-temperature heat storage material stored in the heat storage hot tank 11 is released to heat the carbon dioxide working medium from the diversion pipeline at the cold side inlet of the high-temperature recuperator 8 in the high-temperature heat exchanger 13. The heated working medium at the outlet of the high-temperature heat exchanger 13 enters the auxiliary turbine 10 to generate electricity by doing work, and the unit load is quickly increased; the working medium at the outlet of the auxiliary turbine 10 releases heat in the auxiliary recuperator 9 to heat the diverted working medium from the cold side inlet of the high-temperature recuperator 8, and finally merges into the hot side inlet of the low-temperature recuperator 7, as shown in Fig. 2(c).

[0040] When the present invention stores heat, the extraction steam before the high-pressure turbine is used to heat the heat storage material. While storing the high-temperature heat of the extraction steam, the working medium flow rates of the high- and low-pressure turbines are reduced, thereby reducing the unit load; when releasing heat, the stored high-temperature heat is used to heat the diverted working medium from the inlet side of the high-temperature recuperator. The heated working medium enters the auxiliary turbine to do work, thereby increasing the unit load. In addition, the auxiliary recuperator also recovers the heat of the working medium at the outlet of the auxiliary turbine and is used to preheat the diverted working medium at the inlet side of the high-temperature recuperator, improving the system efficiency. By integrating the heat storage cycle and the heat release cycle, the present invention improves the flexibility of the coal-fired power generation unit, reduces the minimum operating load of the unit, and increases the load change rate. At the same time, the sharing of equipment in the heat storage cycle and the heat release cycle in the present invention greatly simplifies the system structure.

Claims

1. A supercritical carbon dioxide coal-fired power generation system integrated with thermal energy storage, characterized in that, It includes a reheating and recompressing power generation system, a heat storage system and a heat release system; The reheating and recompressing power generation system specifically includes a boiler (1), a high-pressure turbine (2), a low-pressure turbine (3), a recompressor (4), a main compressor (6), a cooler (5), a low-temperature recuperator (7) and a high-temperature recuperator (8); the outlet of the main compressor (6) is successively connected to the cold side of the low-temperature recuperator (7) and the cold side of the high-temperature recuperator (8), the outlet of the cold side of the high-temperature recuperator (8) is connected to the boiler (1), the working medium at the outlet of the boiler (1) is connected to the inlet of the high-pressure turbine (2), the working medium at the outlet of the high-pressure turbine (2) is connected to the boiler (1), the reheated working medium at the outlet of the boiler (1) is connected to the inlet of the low-pressure turbine (3), the outlet of the low-pressure turbine (3) is successively connected to the hot side of the high-temperature recuperator (8) and the hot side of the low-temperature recuperator (7), the outlet of the hot side of the low-temperature recuperator (7) is respectively connected to the inlet of the recompressor (4) and the inlet of the cooler (5), the outlet of the recompressor (4) and the outlet of the cold side of the low-temperature recuperator (7) are connected to the inlet of the cold side of the high-temperature recuperator (8), and the outlet of the cooler (5) is connected to the inlet of the main compressor (6); there is also a shunt pipeline at the inlet of the cold side of the high-temperature recuperator (8) connected to the inlet of the tail of the boiler (1); a high-temperature heat exchanger (13), a cold heat storage tank (12), a hot heat storage tank (11) and an auxiliary turbine (10) constitute the heat storage system and also constitute the heat release system; when constituting the heat storage system, the inlet of the hot side of the high-temperature heat exchanger (13) is connected to the inlet of the high-pressure turbine (2), the outlet of the hot side of the high-temperature heat exchanger (13) is connected to the inlet of the auxiliary turbine (10), the inlet of the cold side of the high-temperature heat exchanger (13) is connected to the cold heat storage tank (12), and the outlet of the cold side of the high-temperature heat exchanger (13) is connected to the hot heat storage tank (11); When constituting the heat release system, the inlet of the cold side of the high-temperature heat exchanger (13) is connected to the shunt pipeline at the inlet of the cold side of the high-temperature recuperator (8), the outlet of the cold side of the high-temperature heat exchanger (13) is connected to the inlet of the auxiliary turbine (10), the inlet of the hot side of the high-temperature heat exchanger (13) is connected to the hot heat storage tank (11), and the outlet of the hot side of the high-temperature heat exchanger (13) is connected to the cold heat storage tank (12); A first valve (141) is provided on the connecting pipeline between the boiler (1) and the inlet of the high-pressure turbine (2), a second valve (142) is provided on the connecting pipeline between the high-temperature heat exchanger (13) and the inlet of the high-pressure turbine (2), and a third valve (143) is provided on the shunt pipeline at the inlet of the cold side of the high-temperature heat exchanger (13) and the inlet of the cold side of the high-temperature recuperator (8).

2. The supercritical carbon dioxide coal-fired power generation system with integrated heat storage according to claim 1, further characterized in that, It also includes an auxiliary recuperator (9); during heat storage, the inlet of the hot side of the auxiliary recuperator (9) is connected to the outlet of the auxiliary turbine (10), the outlet of the hot side of the auxiliary recuperator (9) is connected to the inlet of the hot side of the low-temperature recuperator (7), the inlet of the cold side of the auxiliary recuperator (9) is connected to the shunt pipeline at the inlet of the cold side of the high-temperature recuperator (8), and the outlet of the cold side of the auxiliary recuperator (9) is connected to the inlet of the tail of the boiler (1); the connection relationship during heat release is the same as that during heat storage.

3. The supercritical carbon dioxide coal-fired power generation system with integrated heat storage according to claim 1, further characterized in that, The inlet temperature of the main compressor (6) is 32 - 42 °C.

4. The integrated heat storage supercritical carbon dioxide coal-fired power generation system according to claim 1, further characterized in that, The inlet pressure of the main compressor (6) is 7.5 - 9.0 MPa.

5. A method for operating a supercritical carbon dioxide coal-fired power generation system with integrated heat storage according to any one of claims 1-4, characterized in that, It includes a normal operation mode, a heat storage operation mode and a heat release operation mode: In the normal operation mode, the second valve (142) and the third valve (143) are closed, and the first valve (141) is opened. The high-temperature and high-pressure carbon dioxide working medium at the outlet of the boiler (1) first enters the high-pressure turbine (2) to do work. After the working medium at the outlet of the high-pressure turbine (2) is reheated by the boiler (1), it then enters the low-pressure turbine (3) to do work. The working medium at the outlet of the low-pressure turbine (3) is successively released heat through the high-temperature recuperator (8) and the low-temperature recuperator (7) and is divided into two parts: one part is compressed and boosted by the recompressor (4); the other part is cooled by the cooler (5) and then enters the main compressor (6) to be compressed and boosted. The working medium at the outlet of the main compressor (6) enters the low-temperature recuperator (7) for heating. After the working medium at the cold side outlet of the low-temperature recuperator (7) converges with the working medium at the outlet of the recompressor (4), it is divided again: one part enters the boiler (1) after being heated by the high-temperature recuperator (8); the other part of the working medium directly enters the tail of the boiler (1) to absorb the heat of the medium and low-temperature flue gas, and the two fluids converge in the boiler; In the heat storage operation mode, on the basis of the normal operation mode, the second valve (142) is opened; a part of the working medium at the inlet of the high-pressure turbine (2) is diverted to heat the heat storage material from the cold heat storage tank (12) in the high-temperature heat exchanger (13). After the heat storage material is heated to a high temperature state, it is stored in the hot heat storage tank (11); by diverting, the working medium flow rates of the high-pressure turbine (2) and the low-pressure turbine (3) are reduced, and the unit load is quickly reduced; In the heat release operation mode, on the basis of the normal operation mode, the third valve (143) is opened; the system flow rate and the flow rate of the diversion pipeline at the cold side inlet of the high-temperature recuperator (8) are increased to release the high-temperature heat storage material stored in the hot heat storage tank (11), and heat the carbon dioxide working medium from the diversion pipeline at the cold side inlet of the high-temperature recuperator (8) in the high-temperature heat exchanger (13). The heated working medium at the outlet of the high-temperature heat exchanger (13) enters the auxiliary turbine (10) to do work and generate electricity, and the unit load is quickly increased.

6. A method for operating an integrated heat storage supercritical carbon dioxide coal-fired power generation system according to claim 5. In the heat storage operation mode, in order to reduce the working medium pressure at the outlet of the high-temperature heat exchanger (13), the carbon dioxide working medium at the outlet of the high-temperature heat exchanger (13) enters the auxiliary turbine (10) to expand and do work. After the working medium at the outlet of the auxiliary turbine (10) heats the diverted working medium from the cold side inlet of the high-temperature recuperator (8) in the auxiliary recuperator (9), it converges into the hot side inlet of the low-temperature recuperator (7).

7. A method for operating an integrated heat storage supercritical carbon dioxide coal-fired power generation system according to claim 5. In the heat release operation mode, the working medium at the outlet of the auxiliary turbine (10) releases heat in the auxiliary recuperator (9) to heat the diverted working medium from the cold side inlet of the high-temperature recuperator (8), and finally converges into the hot side inlet of the low-temperature recuperator (7).

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