Fused salt heat storage auxiliary coal-fired unit deep peak regulation system

Abstract

The utility model relates to a fused salt heat storage auxiliary coal-fired unit deep peak shaving system in the field of energy storage. Aiming at the problems that the load of a steam turbine is difficult to adjust to deal with deep peak regulation and the peak regulation operation is unstable in the existing thermal power generating unit, the utility model provides the fused salt heat storage auxiliary coal-fired unit deep peak regulation system which enables the coal-fired unit to change acting and increase or decrease power generation to deal with peak regulation. The system comprises a high-pressure cylinder, a medium-pressure cylinder, a low-pressure cylinder and a fused salt heat storage auxiliary unit composed of a fused salt heat storage device, a fused salt heat release device, a cold salt tank and a hot salt tank, the output of the cold salt tank is connected with the fused salt heat storage device, the output of the fused salt heat storage device is connected with the hot salt tank, the output of the hot salt tank is connected with the fused salt heat release device, and the output of the fused salt heat release device is connected with the cold salt tank. An exhaust pipeline connecting the high-pressure cylinder, the medium-pressure cylinder and the low-pressure cylinder is connected with a reheating pipeline which is connected into the fused salt heat storage device, the reheating pipeline at the rear end of the fused salt heat storage device is connected with the condenser, the fused salt heat release device is connected with auxiliary heating pipelines, and the auxiliary heating pipelines at the front end and the rear end of the fused salt heat release device are connected with a water source and the exhaust pipeline respectively.

Description

Technical Field

[0001] The utility model belongs to the field of energy storage, in particular to a molten salt thermal storage assisted deep peak shaving system for coal-fired units. Background Technique

[0002] At present, the peak-valley difference of the power grid is increasing day by day, and the peak shaving pressure of the power system is also increasing. With the commissioning of UHV transmission projects and the increase in the installed capacity of new energy power generation, the power grid has higher and higher requirements for the flexibility and reliability of regulation. To further tap the peak shaving capacity of thermal power units and ensure the safe and stable operation of the power grid, it has become a development trend for thermal power heating units to perform deep peak shaving operation.

[0003] When a thermal power unit performs deep peak shaving operation, the load of the unit boiler drops significantly, and the furnace temperature also drops accordingly, resulting in problems such as difficult ignition of pulverized coal and poor flame stability, and there is also a major hidden danger of furnace explosion due to fire extinction. Therefore, there is an urgent need for other auxiliaries to help thermal power units cope with peak shaving operation. Without affecting the boiler load, the steam turbine load can be flexibly adjusted, so as to change the work done by the steam turbine to increase / decrease power generation, and ensure the safe and stable operation of the thermal power unit during peak shaving. Content of the Utility Model

[0004] To solve the technical problems that the load of the steam turbine cannot be flexibly adjusted during the deep peak shaving operation of the existing thermal power unit, and there are hidden dangers in the unstable peak shaving operation of the thermal power unit, the utility model provides a molten salt thermal storage assisted deep peak shaving system for coal-fired units. The system helps the coal-fired unit to adjust the steam parameters and change the work done by the steam turbine through molten salt heat storage or heat release without changing the boiler operating parameters, so as to reduce / increase power generation to cope with the peak shaving operation of the power grid.

[0005] The technical solution adopted by the present utility model to solve the technical problem: A molten salt thermal storage assisted coal-fired unit deep peak shaving system, including the high-pressure cylinder, intermediate-pressure cylinder and low-pressure cylinder of the steam turbine. The high-pressure cylinder is connected to an exhaust pipe to supply steam to the intermediate-pressure cylinder and the low-pressure cylinder. The characteristic is that the system includes a molten salt thermal storage device, a molten salt heat release device, and a molten salt thermal storage auxiliary unit composed of a cold salt tank and a hot salt tank. The cold salt tank is connected to the molten salt thermal storage device through a pipeline, and a low-temperature pump is provided on the pipeline. The molten salt thermal storage device is connected to the hot salt tank through a pipeline. The hot salt tank is connected to the molten salt heat release device through a pipeline, and a high-temperature pump is provided on the pipeline. The molten salt heat release device is connected to the cold salt tank through a pipeline. The exhaust pipe branches out a reheater pipeline, and the molten salt thermal storage device is connected to the reheater pipeline. The reheater pipeline behind the molten salt thermal storage device is connected to the condenser. The molten salt thermal storage device can make the molten salt exchange heat with the steam in the reheater pipeline to store heat. The molten salt heat release device is connected to an auxiliary heat pipeline, and the auxiliary heat pipelines before and after the molten salt heat release device are respectively connected to the water source and the exhaust pipe. The molten salt heat release device can make the molten salt exchange heat with the water in the auxiliary heat pipeline to release heat. The present utility model stores and releases heat through molten salt, enabling the steam turbine to adjust the steam parameters according to the actual needs of the power grid, change the work done to increase or decrease power generation, meet the peak shaving requirements of the power grid, and at the same time maintain the safe and stable operation of the boiler, avoiding potential safety hazards caused by changes in the boiler load. Part of the steam output from the high-pressure cylinder is used to heat the molten salt thermal storage, and the work done and power generation of the steam turbine decrease accordingly. When the power grid needs to increase power generation, the molten salt thermal storage is released again to generate steam for supplementation, assisting the steam turbine to do work to increase power generation.

[0006] As a further improvement and supplement to the above technical solution, the present utility model adopts the following technical measures: The molten salt thermal storage device includes a series-connected steam-molten salt condenser and a steam-molten salt heat exchanger. The steam-molten salt condenser is input-connected to the cold salt tank, and the steam-molten salt heat exchanger is output-connected to the hot salt tank. The reheater pipeline passes through the steam-molten salt heat exchanger and the steam-molten salt condenser in sequence; The molten salt heat release device includes a series-connected preheater and a steam generator. The steam generator is input-connected to the hot salt tank, and the preheater is output-connected to the cold salt tank. The auxiliary heat pipeline passes through the preheater and the steam generator in sequence. Both the molten salt thermal storage device and the molten salt heat release device have at least two heat exchanges. When the molten salt stores heat, it passes through the steam-molten salt condenser and the steam-molten salt heat exchanger in sequence to exchange heat with the high-temperature and high-pressure steam sent by the reheater pipeline for heat storage. When the molten salt releases heat, it passes through the steam generator and the preheater in sequence to exchange heat with the water sent by the auxiliary heat pipeline to generate steam.

[0007] The molten salt exothermic device further includes a steam superheater, which is connected in series with the steam generator. The steam superheater is input-connected to the hot salt tank, and the auxiliary heat pipeline sequentially passes through the preheater, the steam generator, and the steam superheater. The molten salt exothermic device also wraps a series-connected steam superheater, which can further heat the steam output by the steam generator, heating the steam from the saturated temperature to the superheated temperature, improving the steam thermal energy, and assisting the subsequent steam turbine to work and generate electricity.

[0008] A reheater is provided on the auxiliary heat pipeline at the rear end of the molten salt exothermic device. The reheater can further heat the steam sent out by the auxiliary heat pipeline, improve the steam energy, and help the steam turbine generate electricity.

[0009] A branch is separated from the auxiliary heat pipeline in front of the reheater and connected to the steam heat exchanger for heat supply, and the branch at the rear end of the steam heat exchanger is connected to the condenser. When there is enough steam in the auxiliary heat pipeline, a branch can be separated from the auxiliary heat pipeline before the reheater and connected to the steam heat exchanger for heat exchange, supplying heat to industrial users or household users in the area where it is located. The steam used by the steam heat exchanger is sent back to the condenser for recovery.

[0010] An deaerating water pump is provided at one end of the auxiliary heat pipeline connected to the water source. The deaerating water pump ensures the quality of the feed water by removing oxygen in the feed water, so as to avoid the corrosion of the contacting metal by the dissolved oxygen in the water, reduce the steam-water loss of power generation, and extend the service life of the equipment.

[0011] The cold salt tank is provided with an intermediate pipeline output-connected to the hot salt tank. An electric heater is provided on the intermediate pipeline, and a transfer pump is provided on the intermediate pipeline in front of the electric heater. The cold salt tank is directly output-connected to the hot salt tank through the intermediate pipeline. When the molten salt exothermically heats to generate insufficient steam for auxiliary power generation, the cold salt tank outputs low-temperature molten salt through the transfer pump, which is heated and raised in temperature by the electric heater and then sent into the hot salt tank to supplement the hot molten salt to generate steam.

[0012] Both the low-temperature pump and the high-temperature pump are molten salt pumps. Molten salt pumps are specifically used for transporting high-temperature molten salts, and have better thermal stability and corrosion resistance compared to common liquid pumps, and have better mechanical strength and sealing at high temperatures.

[0013] The exhaust pipeline is provided with a boiler reheater. The auxiliary heat pipeline is connected to the exhaust pipeline in front of the boiler reheater, and the reheating pipeline is separated from the exhaust pipeline at the rear end of the boiler reheater. The boiler reheater further heats the water vapor sent by the molten salt exothermic device for heating and raising the temperature, improving the steam thermal power supplied to the intermediate and low-pressure cylinders; the reheating pipeline comes from a branch separated from the exhaust pipeline at the rear end of the boiler reheater.

[0014] The utility model provides a molten salt thermal energy storage assisted coal-fired unit deep peak shaving system. The system helps a steam turbine adjust steam parameters to change work done through molten salt heat storage or heat release, enabling the coal-fired unit to flexibly reduce / increase power generation without changing the working parameters of the boiler, coping with the peak shaving operation of the power grid, and ensuring the safe and stable operation of the thermal power unit during peak shaving. Brief Description of the Drawings

[0015] Figure 1 : Schematic structural diagram of the utility model.

[0016] In the figure: 1. High-pressure cylinder, 2. Intermediate and low-pressure cylinder, 3. Exhaust pipe, 4. Boiler reheater, 5. Reheat pipe, 6. Steam-molten salt heat exchanger, 7. Steam-molten salt condenser, 8. Condenser, 9. Heat exchange pipe, 10. Hot salt tank, 11. Cold salt tank, 12. Electric heater, 13. Heat release pipe, 14. Intermediate pipe, 15. Auxiliary heat pipe, 16. Preheater, 17. Steam generator, 18. Reheater, 19. Steam heat exchanger, 20. Return water pipe, 21. Deaerator water pump, 22. Steam superheater, 23. Low-temperature pump, 24. High-temperature pump, 25. Heat user, 26. Transfer pump. Detailed Embodiment

[0017] The following further describes the utility model in conjunction with the description of the drawings and the detailed embodiment.

[0018] As Figure 1As shown, the utility model is a molten salt heat storage auxiliary coal-fired unit deep peak regulation system, including a high-pressure cylinder 1, a medium-pressure cylinder and a low-pressure cylinder of a steam turbine, in which the medium-pressure cylinder and the low-pressure cylinder are simplified as medium- and low-pressure cylinders 2, and the high-pressure cylinder 1 is connected to an exhaust pipe 3 to supply gas to the medium- and low-pressure cylinders. The system also includes a molten salt heat storage device, a molten salt heat release device, a cold salt tank 11 and a hot salt tank 10 connected by pipelines to form a molten salt heat storage auxiliary unit, the cold salt tank 11 is connected to the molten salt heat storage device through a pipeline output, and a low-temperature pump 23 is provided on the pipeline. The molten salt heat storage device is connected to the hot salt tank 10 through a heat exchange pipeline 9 output, and the hot molten salt after heat storage is sent to the hot salt tank 10 for storage, and the hot salt tank 10 is connected to the hot salt tank 10 through a heat release pipeline 1 3 output is connected to the molten salt heat release device, and the hot molten salt is sent out as a heat medium for heat exchange. The heat release pipeline 13 is provided with a high-temperature pump 24. The molten salt heat release device is connected to the cold salt tank 11 through the pipeline output. The exhaust pipeline 3 branches out a reheat pipeline 5. The molten salt heat storage device is connected to the reheat pipeline 5. The reheat pipeline 5 at the rear end of the molten salt heat storage device is connected to the condenser 8. The molten salt heat storage device can make the molten salt and the steam in the reheat pipeline 5 exchange heat to store heat. The molten salt heat release device is connected to an auxiliary heat pipeline 15. The auxiliary heat pipelines 15 at the front and rear ends of the molten salt heat release device are respectively connected to the water source and the exhaust pipeline 3. The molten salt heat release device can make the molten salt and the water in the auxiliary heat pipeline 15 exchange heat to release heat. Both the low-temperature pump and the high-temperature pump use molten salt pumps to ensure mechanical strength and sealing at high temperatures, and at the same time, better corrosion resistance.

[0019] When the power demand of the power grid decreases, the steam output from the high-pressure cylinder enters the molten salt heat storage device to heat the low-temperature cold molten salt sent from the cold salt tank. The cold molten salt is heated and converted into hot molten salt and then input into the hot salt tank for storage. The steam entering the medium and low pressure cylinders decreases, and the power generation of the steam turbine also decreases accordingly. When the power demand of the power grid increases, the hot molten salt stored in the hot salt tank enters the molten salt heat release device to heat the water sent from the auxiliary heat pipeline, generating water vapor to supplement the steam output from the high-pressure cylinder, assisting the medium and low pressure cylinders to do work, so that the power generation of the steam turbine increases. The hot molten salt originally storing heat cools down after heat exchange and turns back into cold molten salt and returns to the cold salt tank for storage. According to the power demand of the power grid, the molten salt is recycled in the molten salt heat storage auxiliary unit composed of the cold salt tank, the molten salt heat storage device, the hot salt tank and the molten salt heat release device. The utility model utilizes molten salt heat storage and heat release, so that the steam turbine can change the steam parameters according to the peak-shaving needs of the power grid, and then change the work to increase or decrease the power generation, meet the peak-shaving requirements of the power grid, and at the same time, the boiler working parameters remain unchanged to maintain stable operation, avoiding the safety hazards caused by the change of boiler load required for the original peak-shaving of the power grid.

[0020] Preferably, the molten salt thermal energy storage device includes a steam molten salt condenser 7 and a steam molten salt heat exchanger 6 connected in series. The input of the steam molten salt condenser 7 is connected to the cold salt tank 11, and the output of the steam molten salt heat exchanger 6 is connected to the hot salt tank 10. The reheating pipeline 5 passes through the steam molten salt heat exchanger 6 and the steam molten salt condenser 7 successively. The low-temperature cold molten salt sent out by the cold salt tank 11 also passes through the steam molten salt condenser 7 and the steam molten salt heat exchanger 6 successively for two heat exchanges to store heat. The heat storage molten salt after heat storage is sent to the hot salt tank 10 for storage. The heat medium for heat exchange in the steam molten salt condenser 7 and the steam molten salt heat exchanger 6 is the hot steam sent by the reheating pipeline 5. The hot steam, as the heat medium, passes through the steam molten salt heat exchanger 6 and the steam molten salt condenser 7 successively for two heat exchanges. At the same time, the molten salt heat release device includes a preheater 16 and a steam generator 17 connected in series. The input of the steam generator 17 is connected to the hot salt tank 10, and the output of the preheater 16 is connected to the cold salt tank 11. The auxiliary heat pipeline 15 passes through the preheater 16 and the steam generator 17 successively, so that the water in the pipeline is used as a supplement after two heat exchanges and sent to the intermediate and low-pressure cylinders for regulation.

[0021] Both the molten salt thermal energy storage device and the molten salt heat release device have at least two heat exchanges. The cold molten salt passes through the steam molten salt condenser and the steam molten salt heat exchanger successively to exchange heat with the high-temperature and high-pressure steam sent by the reheating pipeline for heat storage. The heat storage molten salt passes through the steam generator and the preheater successively for heat release, so that the water sent by the auxiliary heat pipeline exchanges heat to generate steam.

[0022] Preferably, the molten salt heat release device further includes a steam superheater 22. The steam superheater 22 is connected in series with the steam generator 17. The input of the steam superheater 22 is connected to the hot salt tank 10, and the auxiliary heat pipeline 15 passes through the preheater 16, the steam generator 17 and the steam superheater 22 successively. During operation, the molten salt passes through the steam superheater 22, the steam generator 17 and the preheater 16 successively for three heat releases, and the water in the reheating pipeline passes through the preheater 16, the steam generator 17, the steam superheater 22 and the molten salt for three heat exchanges to heat, further improving the steam thermal energy, supplementing the steam of the steam turbine to help generate electricity, and coping with the power grid peak regulation.

[0023] Preferably, a reheater 18 is provided on the auxiliary heat pipeline 15 at the rear end of the molten salt heat release device. A branch is also branched from the auxiliary heat pipeline 15 in front of the reheater 18 to access the steam heat exchanger 19 for heat supply. The steam heat exchanger 19 can be connected to a pipeline to supply heat to the heat user 25. The branch at the rear end of the steam heat exchanger 19 is used as a return water pipeline 20 to connect to the condenser 8. The reheater can further heat the steam sent out by the auxiliary heat pipeline and improve the steam energy to help the steam turbine increase power generation.

[0024] Preferably, a deaerating water pump 21 is provided at one end of the auxiliary heat pipeline 15 connected to the water source. The deaerating water pump can ensure that the water supply in the auxiliary heat pipeline has been deaerated, prevent the dissolved oxygen in the water from corroding the metal equipment passing along the way, and help further reduce the steam-water loss of power generation and extend the service life of the system equipment.

[0025] Preferably, an intermediate pipeline 14 is further provided on the cold salt tank 11 and is output-connected to the hot salt tank 10. An electric heater 12 is provided on the intermediate pipeline 14, and a delivery pump 26 is provided on the intermediate pipeline 14 in front of the electric heater 12. When the molten salt released heat to generate insufficient steam for auxiliary power generation, the cold salt tank outputs low-temperature molten salt through the delivery pump, heats it up through the electric heater, and sends it into the hot salt tank to supplement the hot molten salt to generate steam.

[0026] Preferably, a boiler reheater 4 is provided on the exhaust pipeline 3. The auxiliary heat pipeline 15 is connected to the exhaust pipeline 3 in front of the boiler reheater 4, and the reheating pipeline 5 is branched off from the exhaust pipeline 3 behind the boiler reheater 4. The steam sent by the molten salt heat release device is heated by the boiler reheater to improve the steam heat power supplied to the intermediate and low-pressure cylinders.

[0027] The specific operation process of the present utility model is as follows:

[0028] When the generator set is operating normally, the exhaust steam from the high-pressure cylinder enters the boiler reheater, and the reheated steam enters the intermediate and low-pressure cylinders to do work. When the unit performs deep peak shaving, some of the reheated steam enters the intermediate and low-pressure cylinders. At this time, the boiler parameters remain unchanged. As the input steam volume of the intermediate and low-pressure cylinders decreases, the work done by the steam turbine decreases, and thus the power generation decreases. By adjusting the steam inlet volume into the intermediate and low-pressure cylinders, the work done by the steam turbine can be adjusted, and thus deep peak shaving can be performed. The molten salt thermal energy storage auxiliary unit works as follows:

[0029] First step: Start the low-temperature pump, convey the molten salt in the cold salt tank to the hot salt tank side. The molten salt exchanges heat through the steam-molten salt condenser and the steam-molten salt heat exchanger in sequence to store heat.

[0030] Second step: Some of the steam separated after reheating first enters the steam-molten salt heat exchanger. The high-temperature and high-pressure reheated steam exchanges heat with the molten salt, and the exchanged steam then enters the steam-molten salt condenser to exchange heat with the molten salt.

[0031] Third step: After the cold molten salt sent out by the cold salt tank is heated up through heat exchange in the steam-molten salt condenser and the steam-molten salt heat exchanger in sequence, it enters the hot salt tank for storage. After the cold molten salt in the cold tank reaches the low liquid level, the low-temperature pump is closed to stop outputting molten salt.

[0032] Fourth step: The temperature and pressure of the reheated steam after two heat exchanges decrease, and it is sent into the condenser for recycling.

[0033] Fifth step: When the steam volume is insufficient and the grid load margin is too large, start the delivery pump and the electric heater, send the molten salt in the cold salt tank out through the intermediate pipeline, heat it through the electric heater, and then send it into the hot salt tank.

[0034] When the load of the generator set increases, if there is still a large amount of cold molten salt in the cold salt tank, first stop the low-temperature pump from working.

[0035] First, close the reheating pipeline, stop sending steam to the molten salt thermal energy storage device, and let all the reheated steam enter the intermediate and low-pressure cylinders to do work, thereby increasing the power generation of the unit.

[0036] When the load demand of the generator set continues to increase, the molten salt heat release device starts to work. The deaerating water pump extracts saturated deaerated water, boosts its pressure, and sends it out through the auxiliary heating pipeline. The saturated deaerated water sequentially passes through the preheater, steam generator, and steam superheater. At the same time, the molten salt in the hot salt tank is sent out by the high-temperature pump, and after three heat exchanges successively through the steam superheater, steam generator, and preheater, it is sent back to the cold salt tank. The saturated deaerated water undergoes a phase change when heated by the high-temperature molten salt in the steam generator and steam superheater, and the saturated deaerated water is converted into superheated steam, which is sent back to the boiler reheater along the auxiliary heating pipeline.

[0037] When heat supply is required, or when heat supply is needed during the shutdown of the generator set, the molten salt heat release device works. The saturated deaerated water extracted by the deaerating pump is boosted in pressure and then sent through the preheater, steam generator, and steam superheater. At the same time, the molten salt in the hot salt tank is sent out by the high-temperature pump, and after heat exchanges successively through the steam superheater, steam generator, and preheater, it enters the cold salt tank. The saturated deaerated water undergoes a phase change when heated by the high-temperature molten salt in the steam generator and steam superheater, and the saturated deaerated water is converted into superheated steam. The superheated steam enters the steam heat exchanger for heat supply to conduct heat exchange, providing industrial steam or steam for the park and households. The steam after heat exchange is sent into the condenser for recovery.

Claims

1. A molten salt thermal energy storage assisted deep peak shaving system for coal-fired units, comprising a high-pressure cylinder (1) of a steam turbine, an intermediate-pressure cylinder and a low-pressure cylinder. The high-pressure cylinder (1) is connected to an exhaust gas pipeline (3) to supply gas to the intermediate-pressure cylinder and the low-pressure cylinder. It is characterized in that The system includes a molten salt thermal energy storage device, a molten salt heat release device, and a molten salt thermal energy storage auxiliary unit composed of a cold salt tank (11) and a hot salt tank (10). The cold salt tank (11) is connected to the molten salt thermal energy storage device through a pipeline output, and a low-temperature pump (23) is provided on the pipeline. The molten salt thermal energy storage device is connected to the hot salt tank (10) through a pipeline output. The hot salt tank (10) is connected to the molten salt heat release device through a pipeline output, and a high-temperature pump (24) is provided on the pipeline. The molten salt heat release device is connected to the cold salt tank (11) through a pipeline output. A reheating pipeline (5) is branched from the exhaust pipeline (3), and the molten salt thermal energy storage device is connected to the reheating pipeline (5). The reheating pipeline (5) behind the molten salt thermal energy storage device is connected to the condenser (8). The molten salt thermal energy storage device can enable the molten salt to exchange heat with the steam in the reheating pipeline (5) for heat storage. The molten salt heat release device is connected to an auxiliary heat pipeline (15), and the auxiliary heat pipelines (15) at the front end and the rear end of the molten salt heat release device are respectively connected to a water source and the exhaust pipeline (3). The molten salt heat release device can enable the molten salt to exchange heat with the water in the auxiliary heat pipeline (15) for heat release.

2. The molten salt thermal energy storage assisted coal-fired unit deep peak shaving system according to claim 1, characterized in that The molten salt thermal energy storage device includes a steam-molten salt condenser (7) and a steam-molten salt heat exchanger (6) connected in series. The steam-molten salt condenser (7) is input-connected to the cold salt tank (11), and the steam-molten salt heat exchanger (6) is output-connected to the hot salt tank (10). The reheating pipeline (5) passes through the steam-molten salt heat exchanger (6) and the steam-molten salt condenser (7) in sequence. The molten salt heat release device includes a preheater (16) and a steam generator (17) connected in series. The steam generator (17) is input-connected to the hot salt tank (10), and the preheater (16) is output-connected to the cold salt tank (11). The auxiliary heat pipeline (15) passes through the preheater (16) and the steam generator (17) in sequence.

3. The molten salt thermal energy storage assisted coal-fired unit deep peak shaving system according to claim 2, wherein The molten salt heat release device further includes a steam superheater (22). The steam superheater (22) is connected in series with the steam generator (17). The steam superheater (22) is input-connected to the hot salt tank (10). The auxiliary heat pipeline (15) sequentially passes through the preheater (16), the steam generator (17), and the steam superheater (22).

4. The molten salt thermal energy storage assisted coal-fired unit deep peak shaving system according to claim 1, characterized in that A reheater (18) is provided on the auxiliary heat pipeline (15) at the rear end of the molten salt heat release device.

5. The molten salt thermal energy storage assisted coal-fired unit deep peak shaving system according to claim 4, characterized in that A branch is branched from the auxiliary heat pipeline (15) in front of the reheater (18) to connect to the steam heat exchanger (19) for heating, and the branch behind the steam heat exchanger (19) is connected to the condenser (8).

6. The molten salt thermal energy storage assisted coal-fired unit deep peak shaving system according to claim 1, characterized in that An deaerating water pump (21) is provided at one end of the auxiliary heat pipeline (15) connected to the water source.

7. The molten salt thermal energy storage assisted coal-fired unit deep peak shaving system according to claim 1, wherein An intermediate pipeline (14) is provided on the cold salt tank (11) and output-connected to the hot salt tank (10). An electric heater (12) is provided on the intermediate pipeline (14), and a transfer pump (26) is provided on the intermediate pipeline (14) in front of the electric heater (12).

8. The molten salt thermal energy storage assisted coal-fired unit deep peaking regulation system according to claim 1, wherein Both the low-temperature pump (23) and the high-temperature pump (24) are molten salt pumps.

9. The molten salt thermal energy storage assisted coal-fired unit deep peak shaving system according to any one of claims 1 to 8, characterized in that A boiler reheater (4) is provided on the exhaust pipeline (3). The auxiliary heat pipeline (15) is connected to the exhaust pipeline (3) in front of the boiler reheater (4), and the reheating pipeline (5) is branched from the exhaust pipeline (3) behind the boiler reheater (4).

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