Fused salt electric heating energy storage and flue gas purification coupled flexible peak regulation power generation system

Abstract

The invention provides a flexible peak regulation power generation system coupling fused salt electric heating energy storage and flue gas purification, belongs to the technical field of energy storage and peak regulation, and can at least partially solve the problems that in an existing energy storage technology, electrochemical energy storage is affected by safety and environmental protection requirements, and large-scale application is limited; flywheel energy storage is limited by cost and energy storage capacity, and the application range is narrow; the site selection of a gas storage for compressed air energy storage is greatly influenced by geological conditions; the system comprises a generator set, a fused salt energy storage system and an electric heating energy storage system, and has the beneficial effects that fused salt is heated in a stepped mode through heat generated by compression of a compressor and extracted high-temperature flue gas, the higher heat storage temperature can be achieved while load reduction of the unit is achieved, and the energy storage efficiency is improved. Therefore, in the energy release process, the supercritical CO2 working medium is heated by the high-temperature fused salt to generate power, higher power generation efficiency is achieved, and the energy utilization level of the system is improved.

Description

Technical Field

[0001] This invention belongs to the field of energy storage and peak shaving technology, specifically relating to a flexible peak shaving power generation system that couples molten salt electrothermal energy storage with flue gas purification. Background Technology

[0002] With the continuous expansion of installed capacity of new energy sources such as solar and wind power, the proportion of new energy in my country's power structure has been steadily increasing. However, the power generation process of new energy sources is characterized by significant volatility, intermittency, and geographical limitations, making it difficult to reliably meet the power demand of the power grid. To mitigate the volatility of new energy power generation and effectively absorb clean energy sources such as solar and wind power, coal-fired power generation, mainly based on coal, has taken on the role of regulating power supply, leading to the development of various peak-shaving technologies. However, most existing peak-shaving technologies are based on traditional steam Rankine cycle coal-fired power generating units, which are not entirely applicable to new coal-fired supercritical CO2 cycle power generation systems. Supercritical CO2 cycle power generation technology, as an important development direction of coal-fired power generation technology, has higher cycle thermal efficiency than traditional steam Rankine cycle, and its equipment is compact, simple to arrange, and highly flexible. However, the new power system dominated by new energy sources places higher demands on the peak-shaving of coal-fired power units, and relying solely on supercritical CO2 cycle power generation systems is insufficient to efficiently meet the peak-shaving needs of the power grid. Therefore, energy storage peak-shaving technology is crucial for improving the peak-shaving capacity of generating units and the stability of the power system.

[0003] However, common energy storage technologies each have their limitations. For example, electrochemical energy storage is limited in large-scale application due to safety and environmental requirements; flywheel energy storage is limited in application scope due to cost and energy storage capacity constraints; the site selection of compressed air energy storage facilities is greatly affected by geological conditions; and hot water storage technology has low energy density and cannot meet the energy storage and peak-shaving requirements of supercritical CO2 cycle power generation systems. Therefore, we propose a flexible peak-shaving power generation system that couples molten salt electrothermal energy storage with flue gas purification. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art, and to provide a flexible peak-shaving power generation system that couples molten salt electrothermal energy storage and flue gas purification.

[0005] This invention provides a flexible peak-shaving power generation system that couples molten salt electrothermal energy storage with flue gas purification, comprising: A generator set, comprising a boiler and a turbine connected to the boiler piping; An electrothermal energy storage system includes a compressor electrically connected to the generator set, a cold-side inlet of a molten salt heater connected to the compressor via piping, and an energy storage regenerator connected to the molten salt heater, for use in consuming surplus electricity from the generator set during operation to compress a working fluid to obtain a thermal working fluid; and The molten salt energy storage system includes a flue gas-molten salt heat exchanger installed in the bypass flue of the boiler and a high-temperature storage tank connected to the flue gas-molten salt heat exchanger pipeline. The flue gas-molten salt heat exchanger pipeline is connected to the molten salt outlet of the molten salt heater, so as to convert the heat of the compressor and the boiler bypass flue gas into the heat of molten salt during operation.

[0006] Furthermore, the flexible peak-shaving power generation system also includes a pollutant desorption system, which includes a low-temperature adsorption tower and a dust collector and a flue gas cooler arranged sequentially on the flue gas pipeline of the boiler. The flue gas outlet of the low-temperature adsorption tower is connected to the flue gas inlet pipeline of the first auxiliary precooler, and the low-temperature adsorption tower is connected to the flue gas outlet pipeline of the flue gas cooler.

[0007] Specifically, the generator set also includes a main compressor, a low-temperature regenerator, and a high-temperature regenerator connected in sequence by pipelines. The high-temperature regenerator is connected to the boiler pipeline. The inlet of the main compressor is connected to the precooler pipeline. The high-temperature storage tank is connected to a molten salt-CO2 heat exchanger for cooling the molten salt in the high-temperature storage tank during operation. The molten salt-CO2 heat exchanger is connected to a low-temperature storage tank for storing the cooled molten salt during operation.

[0008] Specifically, the boiler is connected to the turbine via a working fluid delivery pipeline, the turbine is connected to the hot-side inlet and outlet pipelines of the high-temperature regenerator, and a regeneration pipeline is provided between the high-temperature regenerator and the low-temperature regenerator to transport the heated working fluid back to the low-temperature regenerator during operation.

[0009] Preferably, the generator set further includes a re-compressor, the inlet of which is connected to the hot-side outlet pipeline of the cryogenic regenerator, and the outlet of which is connected to the cold-side outlet pipeline of the cryogenic regenerator.

[0010] Specifically, the cold-side outlet of the low-temperature regenerator is connected to the cold-side inlet pipe of the energy release regenerator, and the cold-side outlet of the energy release regenerator is connected to the CO2-side inlet pipe of the molten salt-CO2 heat exchanger.

[0011] Furthermore, the CO2 side outlet of the molten salt-CO2 heat exchanger is connected to the inlet pipe of the energy-releasing turbine, the outlet of the energy-releasing turbine is connected to the hot side inlet pipe of the energy-releasing regenerator, and the hot side outlet of the energy-releasing regenerator is connected to the hot side inlet pipe of the low-temperature regenerator.

[0012] Furthermore, a flue gas inlet baffle is installed at the inlet of the bypass flue of the boiler, and a flue gas outlet baffle is installed at the outlet of the bypass flue of the boiler.

[0013] Furthermore, the low-temperature regenerator is connected to the hot-side inlet pipe of the second auxiliary precooler, the hot-side outlet of the second auxiliary precooler is connected to the inlet pipe of the precooler, the cold-side inlet of the second auxiliary precooler is connected to the heat medium outlet pipe of the low-temperature adsorption tower, and the cold-side outlet of the second auxiliary precooler is connected to the heat medium inlet pipe of the low-temperature adsorption tower; the second auxiliary precooler is arranged in parallel with the first auxiliary precooler.

[0014] Specifically, the refrigerant inlet of the low-temperature adsorption tower is connected to the cold-side outlet pipe of the low-temperature cooler to reduce the flue gas temperature inside the low-temperature adsorption tower during operation. The hot-side outlet of the energy storage regenerator is connected to the inlet pipe of the low-temperature expander to increase the working fluid temperature entering the low-temperature expander during operation. The outlet of the low-temperature expander is connected to the hot-side inlet pipe of the low-temperature cooler, and the hot-side outlet of the low-temperature cooler is connected to the cold-side inlet pipe of the energy storage regenerator.

[0015] The beneficial effects of this invention are as follows: By utilizing the heat generated from compressor compression and the cascade heating of molten salt from extracted high-temperature flue gas, the system achieves higher thermal storage temperatures while simultaneously reducing unit load. This allows for the high-temperature molten salt to heat supercritical CO2 working fluid during energy release, resulting in higher power generation efficiency and improved system energy utilization. The cryogenic expander recovers some useful work during energy storage, reducing direct throttling losses and improving system energy efficiency. The cryogenic cooler generates low-temperature cooling energy for cascade cooling of the adsorbent in the cryogenic adsorption tower and the flue gas in the flue gas cooling tower, enhancing the adsorbent's ability to adsorb low-temperature pollutants while reducing the need for energy storage equipment and lowering storage costs. Utilizing the waste heat from the main system's cold end to heat the clean flue gas and the adsorbent in the cryogenic adsorption tower reduces energy loss. This invention's energy storage system can improve the unit's peak shaving and frequency regulation capabilities. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the connection of a flexible peak-shaving power generation system that couples molten salt electrothermal energy storage and flue gas purification according to a specific embodiment of the present invention. The components include: 1. Main compressor; 2. Low-temperature regenerator; 3. High-temperature regenerator; 4. Boiler; 401. Flue gas-molten salt heat exchanger; 402. Flue gas inlet damper; 403. Flue gas outlet damper; 5. Turbine; 6. Precooler; 7. Recompressor; 8. Low-temperature storage tank; 9. High-temperature storage tank; 10. Compressor; 11. Molten salt heater; 12. Energy storage regenerator; 13. Low-temperature expander; 14. Low-temperature cooler; 15. Energy release regenerator; 16. Molten salt-CO2 heat exchanger; 17. Energy release turbine; 18. Dust collector; 19. Flue gas cooler; 20. Low-temperature adsorption tower; 21. First auxiliary precooler; 22. Second auxiliary precooler. Detailed Implementation

[0017] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] like Figure 1 As shown in the figure, a flexible peak-shaving power generation system coupled with molten salt electrothermal energy storage and flue gas purification provided by a specific embodiment of the present invention includes: a generator set, which includes a boiler 4 and a turbine 5 connected to the boiler 4 by pipeline; an electrothermal energy storage system, including a compressor 10 electrically connected to the generator set, a cold-side inlet of a molten salt heater 11 connected to the compressor 10, and an energy storage regenerator 12 connected to the molten salt heater 11, for use in the operation of consuming surplus electricity from the generator set to compress the working fluid to obtain a heat working fluid; and a molten salt energy storage system, including a flue gas-molten salt heat exchanger 401 installed in the bypass flue of the boiler 4 and a high-temperature storage tank 9 connected to the flue gas-molten salt heat exchanger 401 by pipeline, and a molten salt outlet of the flue gas-molten salt heat exchanger 401 connected to the molten salt heater 11 by pipeline, for use in the operation of converting the heat of the compressor 10 and the bypass flue gas of the boiler 4 into the heat of the molten salt.

[0019] Specifically, the compressor 10 has an outlet temperature of 350-600℃ and is used to heat molten salt. When the molten salt energy storage system releases energy, it heats the CO2 working fluid through the molten salt-CO2 heat exchanger 16 to increase the enthalpy of the working fluid and drive the energy-releasing turbine to do work.

[0020] Furthermore, the input end of the molten salt-CO2 heat exchanger 16 comes from the high-temperature molten salt in the high-temperature storage tank 9; the high-temperature molten salt exchanges heat with the CO2 working medium, transferring the heat in the molten salt to the CO2; after cooling, the molten salt flows into the low-temperature storage tank 8, realizing the recycling of molten salt.

[0021] Furthermore, the input end of the molten salt heater 11 is the high-temperature working fluid output by the compressor 10; the high-temperature working fluid passes through the molten salt heater 11 and transfers its heat to the molten salt; after the working fluid cools down, it flows out and enters the downstream energy storage and regenerator 12; the temperature of the molten salt rises and is sent to the high-temperature storage tank 9, realizing the storage of electrical energy converted into thermal energy.

[0022] Based on the above basic implementation method, the system also includes a pollutant desorption system, which includes a low-temperature adsorption tower 20 and a dust collector 18 and a flue gas cooler 19 installed on the flue gas pipeline of the boiler 4. The flue gas outlet of the low-temperature adsorption tower 20 is connected to the flue gas inlet pipeline of the first auxiliary precooler 21, and the flue gas outlet pipeline of the low-temperature adsorption tower 20 is connected to the flue gas outlet pipeline of the flue gas cooler 19.

[0023] Specifically, the cooling capacity generated by the cryogenic cooler 14 is transferred to the flue gas cooler 19 and the cryogenic adsorption tower 20 through an intermediate refrigerant, and the refrigerant outlet temperature of the cryogenic cooler 14 is -30 to -5℃.

[0024] In one specific embodiment, the generator set further includes a main compressor 1, a low-temperature regenerator 2, and a high-temperature regenerator 3 connected in sequence by pipelines. The high-temperature regenerator 3 is connected to the boiler 4 by pipelines. The inlet of the main compressor 1 is connected to the precooler 6 by pipelines. The high-temperature storage tank 9 is connected to a molten salt-CO2 heat exchanger 16 for cooling the molten salt in the high-temperature storage tank 9 during operation. The molten salt-CO2 heat exchanger 16 is connected to a low-temperature storage tank 8 for storing the cooled molten salt during operation.

[0025] In this embodiment, the precooler 6 reduces the temperature of the working fluid entering the main compressor 1, thereby reducing the compression work; at the same time, it can improve the overall cycle efficiency.

[0026] In another specific embodiment, the boiler 4 is connected to the turbine 5 through a working fluid conveying pipeline, the turbine 5 is connected to the hot side inlet and outlet pipelines of the high-temperature regenerator 3, and a regeneration pipeline is provided between the high-temperature regenerator 3 and the low-temperature regenerator 2 to transport the heated working fluid back to the low-temperature regenerator 2 during operation.

[0027] Specifically, the generator set also includes a re-compressor 7, the inlet of which is connected to the hot side outlet pipeline of the low-temperature regenerator 2, and the outlet of the re-compressor 7 is connected to the cold side outlet pipeline of the low-temperature regenerator 2.

[0028] Furthermore, the low-temperature regenerator 2 recovers the heat of the medium- and high-temperature working fluid from the turbine exhaust and uses it to heat the low-temperature working fluid at the outlet of the main compressor 1 or the re-compressor 7; this reduces the heating demand of the boiler 4 and improves fuel utilization; the re-compressor 7 reduces the load on the main compressor 1, increases the regeneration ratio, and reduces irreversible losses.

[0029] In one specific implementation, the cold-side outlet of the low-temperature regenerator 2 is connected to the cold-side inlet pipe of the energy release regenerator 15, and the cold-side outlet of the energy release regenerator 15 is connected to the CO2-side inlet pipe of the molten salt-CO2 heat exchanger 16.

[0030] In this embodiment, the CO2 side outlet of the molten salt-CO2 heat exchanger 16 is connected to the inlet pipe of the energy release turbine 17, the outlet of the energy release turbine 17 is connected to the hot side inlet pipe of the energy release regenerator 15, and the hot side outlet of the energy release regenerator 15 is connected to the hot side inlet pipe of the low temperature regenerator 2.

[0031] Specifically, the function of the energy release regenerator 15 is to recover the waste heat from the exhaust gas of the energy release turbine, reduce cold-end losses, and form a cascaded regeneration network through connection with the molten salt-CO2 heat exchanger 16 and the low-temperature regenerator 2, realizing efficient coupling and recycling between molten salt thermal energy, CO2 working fluid, and electrical energy. The molten salt-CO2 heat exchanger 16 transfers the heat of the high-temperature molten salt to the CO2 working fluid, causing it to heat up and pressurize. The heated CO2 enters the energy release turbine 17 and expands, its volume increasing rapidly, driving the turbine blades to rotate. The turbine is connected to the generator, thereby converting the molten salt thermal energy into electrical energy output. In the energy storage stage, the system uses electrical energy to drive the compressor, "compressing" the energy into molten salt (stored in the form of thermal energy). In the energy release stage, the thermal energy of the molten salt is "released" into electrical energy through the work done by the turbine expansion. The energy release turbine 17 is the "key conversion point" between the energy storage and power generation stages. When the power system is under high load and needs additional power, the energy release turbine 17 is activated; the high-temperature heat energy of molten salt is converted into electricity through CO2 working fluid, which quickly regulates the grid demand; therefore, its function is to support the flexible peak-shaving function of the entire system.

[0032] In another specific embodiment, a flue gas inlet baffle 402 is installed at the inlet of the bypass flue of boiler 4, and a flue gas outlet baffle 403 is installed at the outlet of the bypass flue of boiler 4; the low-temperature regenerator 2 is connected to the hot-side inlet pipeline of the second auxiliary precooler 22, the hot-side outlet of the second auxiliary precooler 22 is connected to the inlet pipeline of the precooler 6, the cold-side inlet of the second auxiliary precooler 22 is connected to the heat medium outlet pipeline of the low-temperature adsorption tower 20, and the cold-side outlet of the second auxiliary precooler 22 is connected to the heat medium inlet pipeline of the low-temperature adsorption tower 20; the second auxiliary precooler 22 is arranged in parallel with the first auxiliary precooler 21; the refrigerant inlet of the low-temperature adsorption tower 20 is connected to the cold side outlet pipe of the low-temperature cooler 14 to reduce the flue gas temperature in the low-temperature adsorption tower 20 during operation; the hot side outlet of the energy storage regenerator 12 is connected to the inlet pipe of the low-temperature expander 13 to increase the working fluid temperature entering the low-temperature expander 13 during operation; the outlet of the low-temperature expander 13 is connected to the hot side inlet pipe of the low-temperature cooler 14; and the hot side outlet of the low-temperature cooler 14 is connected to the cold side inlet pipe of the energy storage regenerator 12.

[0033] Furthermore, the cold-side heat medium of the second auxiliary precooler 22 is hot water. The hot water absorbs the waste heat from the cold end of the unit through the second auxiliary precooler 22 and enters the low-temperature adsorption tower 20 to heat the adsorbent, thereby realizing pollutant desorption and adsorbent regeneration. The low-temperature adsorption tower 20 is a dual-tower arrangement. After the adsorption in the first tower is saturated, it switches to the second tower for adsorption. The adsorbent in the first tower is heated, desorbed, and regenerated for the next use, and the same applies to the second tower. The clean flue gas at the outlet of the low-temperature adsorption tower 20 is heated to 70~90℃ in the first auxiliary precooler 21 and then discharged into the atmosphere through the chimney. This can reduce chimney corrosion and increase the rise height of the flue gas when it is discharged from the chimney, thereby enhancing the pollutant diffusion distance. The flue gas inlet temperature on the flue gas side of the flue gas-molten salt heat exchanger 401 is ≥600℃, and the flue gas outlet temperature on the flue gas side of the flue gas-molten salt heat exchanger 401 is ≥350℃.

[0034] Furthermore, the first auxiliary precooler 21 reduces the working fluid / flue gas temperature and decreases the compression work; the second auxiliary precooler 22 introduces low-temperature cold energy into the flue gas purification process to enhance adsorption; the low-temperature cooler 14 provides a stable low-temperature cold source to serve electrothermal energy storage and flue gas desorption; the low-temperature expander 13 generates cold during the energy storage process, realizing the simultaneous conversion of electrical energy into high-temperature heat and low-temperature cold.

[0035] To aid in a better understanding of the invention, a more comprehensive and specific embodiment is described. In this embodiment, the invention provides a flexible peak-shaving power generation system coupling molten salt electrothermal energy storage and flue gas purification, comprising: a generator set, a molten salt energy storage system, an electrothermal energy storage system, and a cryogenic pollutant removal system, wherein... The main compressor 1 outlet, low-temperature regenerator 2 cold-side inlet and outlet, high-temperature regenerator 3 cold-side inlet and outlet, boiler 4 working fluid inlet and outlet, turbine 5 inlet and outlet, high-temperature regenerator 3 hot-side inlet and outlet, low-temperature regenerator 2 hot-side inlet and outlet, first auxiliary precooler 21 inlet and outlet, precooler 6 inlet and outlet, and main compressor 1 inlet are connected sequentially by pipelines. The re-compressor 7 inlet and outlet are connected to the low-temperature regenerator 2 hot-side outlet and low-temperature regenerator 2 cold-side outlet pipelines, respectively. In the molten salt energy storage system, the low-temperature storage tank 8 outlet is connected to the first-stage molten salt heater 11 molten salt inlet pipeline, the molten salt heater 11 molten salt outlet is connected to the second-stage molten salt heater 401 molten salt inlet pipeline, the flue gas-molten salt heat exchanger 401 molten salt outlet is connected to the high-temperature storage tank 9 inlet pipeline, and the high-temperature storage tank 9 outlet is connected to the molten salt-CO2 heat exchanger 1. 6. Molten salt inlet pipeline connection; molten salt outlet of molten salt-CO2 heat exchanger 16 is connected to inlet pipeline of cryogenic storage tank 8; For the electric thermal energy storage system, during energy storage, compressor 10 outlet is connected to cold-side inlet pipeline of molten salt heater 11; cold-side outlet of molten salt heater 11 is connected to hot-side inlet pipeline of energy storage regenerator 12; hot-side outlet of energy storage regenerator 12 is connected to inlet pipeline of cryogenic expander 13; outlet of cryogenic expander 13 is connected to hot-side inlet pipeline of cryogenic cooler 14; hot-side outlet of cryogenic cooler 14 is connected to cold-side inlet pipeline of energy storage regenerator 12; cold-side outlet of energy storage regenerator 12 is connected to inlet pipeline of compressor 10; During energy release, cold-side outlet of cryogenic regenerator 2 is connected to cold-side inlet pipeline of energy release regenerator 15; cold-side outlet of energy release regenerator 15 is connected to molten salt-CO2 heat exchanger 16. The CO2 side inlet pipe is connected to the molten salt-CO2 heat exchanger 16. The CO2 side outlet is connected to the inlet pipe of the energy release turbine 17. The outlet of the energy release turbine 17 is connected to the hot side inlet pipe of the energy release regenerator 15. The hot side outlet of the energy release regenerator 15 is connected to the hot side inlet pipe of the low-temperature regenerator 2. In the low-temperature pollutant removal system, the boiler exhaust enters the inlet of the dust collector 18. The outlet of the dust collector 18 is connected to the flue gas inlet pipe of the flue gas cooler 19. The flue gas outlet of the flue gas cooler 19 is connected to the flue gas inlet pipe of the low-temperature adsorption tower 20. The flue gas outlet of the low-temperature adsorption tower 20 is connected to the flue gas inlet pipe of the first auxiliary precooler 21. The cold side outlet of the low-temperature cooler 14 is connected to the refrigerant inlet pipe of the low-temperature adsorption tower 20. The refrigerant outlet of the low-temperature adsorption tower 20 is connected to the refrigerant inlet pipe of the flue gas cooler 19. The refrigerant outlet of the flue gas cooler 19 is connected to the cold side inlet pipe of the low-temperature cooler 14.

[0036] In this embodiment, the working fluid of the loop consisting of compressor 10, molten salt heater 11, energy storage regenerator 12, cryogenic expander 13 and cryogenic cooler 14 is CO2 or air. When the working fluid is CO2, the loop cycle is a reverse Rankine cycle; when the working fluid is air, the loop cycle is a reverse Brayton cycle.

[0037] Furthermore, the system operates as follows: During energy storage, a high-temperature heat pump system consisting of compressor 10, molten salt heater 11, energy storage regenerator 12, cryogenic expander 13, and cryogenic cooler 14 consumes surplus electricity and converts it into heat medium and cryogenic cooling capacity. The heat medium heats the molten salt from cryogenic storage tank 8 to a certain temperature through molten salt heater 11. High-temperature flue gas further heats the molten salt to an even higher temperature through flue gas-molten salt heat exchanger 401, and then the molten salt is stored in high-temperature storage tank 9 as heat medium. This process, on the one hand, reduces unit output by consuming surplus electricity through high-pressure compressor 10; on the other hand, boiler 4 extracts some high-temperature flue gas and uses flue gas-molten salt heat exchanger 401 to heat the molten salt, thereby reducing the heat absorption of the supercritical CO2 cycle in the boiler and thus reducing unit output, achieving the effect of unit load reduction. Although the inlet working fluid of cryogenic expander 13 has a low temperature, it has a high pressure and a certain work-doping capacity, which can recover some useful work and reduce energy loss. During energy storage, the pollutant removal process... Simultaneously, the boiler flue gas first passes through dust collector 18 for dust removal, then enters flue gas cooling tower 19, where it is cooled to about 5°C by the low-temperature cooler 14 in the heat pump. Water vapor in the flue gas condenses into water, and some pollutants such as nitrogen oxides, sulfur oxides, and Hg dissolve in the water and are discharged, achieving partial removal of pollutants. Then, the flue gas enters low-temperature adsorption tower 20, where it is further cooled to about -15°C by the low-temperature cooler 14, and the pollutants are almost completely absorbed by the adsorbent. After the clean flue gas is discharged, it is heated to 70~90°C by the system's cold end waste heat through the first auxiliary precooler 21 and discharged into the atmosphere. On the one hand, it can recover the cold end waste heat and reduce energy loss; on the other hand, it can reduce chimney corrosion and increase the pollutant diffusion distance. The low-temperature adsorption tower 20 is arranged in a dual-tower configuration. After the adsorbent in the first tower is saturated, it switches to the second tower for operation. The saturated adsorbent in the first tower is heated to 70~90°C by the system's cold end waste heat through the second auxiliary precooler 22, causing pollutants to precipitate out and the adsorbent to be regenerated for the next use. The same applies to the second tower. While achieving pollutant removal, the system also utilizes the cooling capacity of the low-temperature cooler 14 and the waste heat at the cold end of the main system during energy storage, improving system energy efficiency. Simultaneously, it avoids storing cooling capacity, reduces storage equipment, and lowers energy storage costs. During energy release, a portion of the CO2 working fluid diverted from the cold-side outlet of the low-temperature regenerator 2 is heated by the high-temperature molten salt from the high-temperature storage tank 9 after absorbing heat in the energy release regenerator 15. It then enters the molten salt-CO2 heat exchanger 16, where it is heated by the high-temperature molten salt from the high-temperature storage tank 9. The heated CO2 then enters the energy release turbine 17, where it expands and performs work, thereby increasing the unit's output. The high-temperature exhaust gas from the energy release turbine 17 is cooled and released in the regenerator 15 before returning to the hot-side inlet of the low-temperature regenerator 2. This process enables the unit to achieve peak load operation.

[0038] In summary, the embodiments disclosed herein have at least the following technical effects: Enhance energy storage and peak-shaving capabilities: This system achieves efficient bidirectional conversion between electrical energy and thermal energy through the coupling of "electrothermal energy storage + molten salt energy storage + supercritical CO2 cycle". Molten salt energy storage has the advantages of high energy density and large-scale energy storage, overcoming the shortcomings of traditional electrochemical energy storage, compressed air energy storage, and hot water energy storage in terms of safety, site selection and energy density. The system can be flexibly dispatched to adapt to the peak-valley difference of the power grid and the fluctuating power generation demand of new energy sources. Improve energy efficiency: The system employs a multi-stage heat exchange and waste heat recovery device, including a low-temperature regenerator, an energy release regenerator, and a recompressor, to fully utilize the waste heat of the working fluid and reduce cold-end losses. During the energy storage and release process, both heat and cold are generated, and the heat working fluid is stored in molten salt for efficient reuse. The low-temperature cooling capacity is used for flue gas cooling and pollutant desorption, achieving cascaded utilization of energy. Coupled flue gas purification function: The system integrates a dust collector, a flue gas cooler, and a low-temperature adsorption tower. Combined with the cold source provided by the low-temperature cooler and auxiliary precooler, it achieves deep cooling of the boiler flue gas; SO2 and NO are removed through low-temperature adsorption. X The system effectively removes pollutants, reduces emissions, and meets stringent environmental protection requirements; it forms an integrated system of "power generation - energy storage - purification," taking into account both energy utilization and environmental governance. Enhance system flexibility and economy: During the energy storage phase, the system utilizes surplus electricity from off-peak hours to drive a compressor, converting electrical energy into high-temperature molten salt heat energy and low-temperature cold energy. During the energy release phase, the system uses high-temperature molten salt to drive a turbine for power generation via CO2 working fluid, achieving rapid peak shaving and high electricity-heat-electricity conversion efficiency. It has the ability to shave peaks and fill valleys, smooth out fluctuations in new energy sources, and improve the stability of grid operation.

[0039] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A flexible peak shaving power generation system coupling molten salt electrothermal energy storage and flue gas purification, characterized in that, The system comprises: a generator set comprising a boiler and a turbine connected to the boiler by a pipeline; an electric heat energy storage system comprising a compressor electrically connected to the generator set, a molten salt heater cold side inlet connected to the compressor by a pipeline, and an energy storage regenerator connected to the molten salt heater, for converting the surplus power of the generator set into heat during operation to compress the working medium to obtain hot working medium; and a molten salt energy storage system comprising a flue gas-molten salt heat exchanger arranged in a bypass flue duct of the boiler, and a high-temperature storage tank connected to the flue gas-molten salt heat exchanger by a pipeline, and a molten salt outlet of the flue gas-molten salt heat exchanger connected to the molten salt heater, for converting the heat of the compressor and the boiler bypass flue gas into the heat of the molten salt during operation.

2. The flexible peak shaving power generation system of coupling molten salt electrothermal energy storage with flue gas purification according to claim 1, characterized in that, The flexible peak shaving power generation system further comprises a pollutant desorption system comprising a low-temperature adsorption tower and a dust remover and a flue gas cooler arranged in the flue gas pipeline of the boiler in sequence, a flue gas outlet of the low-temperature adsorption tower connected to a flue gas inlet of a first auxiliary pre-cooler by a pipeline, and a flue gas outlet of the low-temperature adsorption tower connected to a flue gas outlet of the flue gas cooler by a pipeline.

3. The flexible peak shaving power generation system of coupling molten salt electrothermal energy storage with flue gas purification according to claim 1, characterized in that, The generator set further comprises a main compressor, a low-temperature regenerator and a high-temperature regenerator connected in sequence by a pipeline, the high-temperature regenerator connected to the boiler by a pipeline, an inlet of the main compressor connected to a pre-cooler by a pipeline, and a molten salt-CO2 heat exchanger connected to the high-temperature storage tank for cooling the molten salt in the high-temperature storage tank during operation, and a low-temperature storage tank connected to the molten salt-CO2 heat exchanger for storing the cooled molten salt during operation.

4. The flexible peak shaving power generation system of coupling molten salt electrothermal energy storage with flue gas purification according to claim 3, characterized in that, The boiler is connected to the turbine by a working medium conveying pipeline, the turbine is connected to a hot side inlet and outlet of the high-temperature regenerator by a pipeline, and a regenerative pipeline is arranged between the high-temperature regenerator and the low-temperature regenerator for conveying the heated working medium back to the low-temperature regenerator during operation.

5. The flexible peak shaving power generation system of coupling molten salt electrothermal energy storage with flue gas purification according to claim 3, characterized in that, The generator set further comprises a re-compressor, an inlet of the re-compressor connected to a hot side outlet of the low-temperature regenerator by a pipeline, and an outlet of the re-compressor connected to a cold side outlet of the low-temperature regenerator by a pipeline.

6. The flexible peak shaving power generation system of coupling molten salt electrothermal energy storage with flue gas purification according to claim 3, characterized in that, A cold side inlet of the low-temperature regenerator is connected to a cold side inlet of an energy release regenerator by a pipeline, and a CO2 side inlet of the molten salt-CO2 heat exchanger is connected to a CO2 side outlet of the energy release regenerator by a pipeline.

7. The flexible peak shaving power generation system coupling molten salt electrothermal energy storage with flue gas cleaning according to claim 6, characterized in that, A CO2 side outlet of the molten salt-CO2 heat exchanger is connected to an inlet of an energy release turbine by a pipeline, an outlet of the energy release turbine is connected to a hot side inlet of the energy release regenerator by a pipeline, and a hot side outlet of the energy release regenerator is connected to a hot side inlet of the low-temperature regenerator by a pipeline.

8. The flexible peak shaving power generation system coupling molten salt electrothermal energy storage with flue gas cleaning of claim 1, wherein, A flue gas inlet baffle is arranged at an inlet of the bypass flue duct of the boiler, and a flue gas outlet baffle is arranged at an outlet of the bypass flue duct of the boiler.

9. The flexible peak shaving power generation system coupling molten salt electrothermal energy storage with flue gas cleaning of claim 1, wherein, A hot side inlet of the low-temperature regenerator is connected to a hot side inlet of a second auxiliary pre-cooler by a pipeline, a hot side outlet of the second auxiliary pre-cooler is connected to an inlet of the pre-cooler by a pipeline, a cold side inlet of the second auxiliary pre-cooler is connected to a hot medium outlet of the low-temperature adsorption tower by a pipeline, and a cold side outlet of the second auxiliary pre-cooler is connected to a hot medium inlet of the low-temperature adsorption tower by a pipeline; and the second auxiliary pre-cooler is arranged in parallel with the first auxiliary pre-cooler.

10. The flexible peak shaving power generation system coupling molten salt electrothermal energy storage with flue gas cleaning of any one of claims 1 to 9, wherein, The cryogenic adsorption column is connected to a cold side outlet of a cryogenic cooler for reducing the flue gas temperature in the cryogenic adsorption column during operation, the hot side outlet of the energy storage regenerator is connected to an inlet of a cryogenic expander for increasing the working fluid temperature entering the cryogenic expander during operation, the outlet of the cryogenic expander is connected to a hot side inlet of the cryogenic cooler, and the hot side outlet of the cryogenic cooler is connected to a cold side inlet of the energy storage regenerator.

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