A molten salt energy storage peak shaving system for a thermal power plant

Abstract

The application provides a thermal power plant molten salt energy storage peak shaving system and belongs to the technical field of energy storage. The system comprises a steam compressor, a steam-molten salt heat exchanger, a low-temperature molten salt storage tank, a high-temperature molten salt storage tank, a superheater, a booster compressor, an evaporator, a preheater, a boiler feed water heater and a high-temperature water storage tank. When the unit deeply stores energy for peak shaving, high-temperature molten salt is formed by heat exchange between high-temperature steam from the boiler and low-temperature molten salt, and condensed saturated water is stored in the high-temperature water storage tank. When the unit releases energy for peak shaving, hot water from the high-temperature water storage tank is initially pressurized by a high-temperature water pump, enters the preheater to be heated to a temperature close to the evaporation temperature, then enters the evaporator to be evaporated into saturated water vapor, enters the booster compressor, is compressed to the pressure of the boiler steam, enters the superheater, is heated to be superheated, and is then led to the boiler to improve the peak capacity of the boiler. The system stores excess heat energy. During the low electricity consumption period, the amount of thermal power grid electricity is reduced. During the high electricity consumption period, the stored heat energy is released to increase the amount of grid electricity.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, and in particular to a molten salt energy storage peak-shaving system for thermal power plants. Background Technology

[0002] Large-scale, low-cost energy storage technology is a crucial support for achieving the "dual carbon" goal and a cornerstone and hallmark of the construction of new energy and power systems. High-temperature molten salt thermal energy storage, as a novel energy storage method, has experienced rapid development due to its mature technology, safety, high efficiency, and lack of geographical limitations. Its main applications include solar thermal power generation, peak shaving of coupled thermal power units, independent energy storage power stations, and green electricity heating.

[0003] Deep peak shaving in power plants refers to the ability of thermal power units to rapidly adjust their output to operate at 30% or even lower load for short periods when there are significant fluctuations in the power system load, in order to meet the requirements for the safe and stable operation of the power grid. The main methods of deep peak shaving in thermal power plants include adjusting fuel quantity, steam quantity, and turbine extraction steam quantity. During deep peak shaving in thermal power plants, various factors need to be comprehensively considered, such as unit performance, grid load demand, and environmental conditions, to ensure the safe and stable operation of the units. However, existing molten salt energy storage peak shaving schemes cannot achieve deep peak shaving because the main steam pressure is too low when the unit load is low, preventing the use of steam to heat the molten salt. This results in a waste of thermal energy due to the low conversion and storage of thermal energy.

[0004] In view of the above reasons, the present invention proposes a molten salt energy storage peak-shaving system for thermal power plants to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a molten salt energy storage peak-shaving system for thermal power plants. By adding a molten salt energy storage peak-shaving system to a thermal power plant, excess thermal energy can be converted into thermal energy and stored through energy storage facilities. During periods of low electricity demand, the amount of thermal power fed into the grid is reduced, while the amount of solar and wind power fed into the grid is increased. During periods of high electricity demand, the stored thermal energy is released, increasing the amount of power fed into the grid, thus achieving the purpose of deep peak shaving for the unit.

[0006] This invention provides a molten salt energy storage and peak-shaving system for thermal power plants, comprising: a steam compressor, a steam-molten salt heat exchanger, a low-temperature molten salt storage tank, a high-temperature molten salt storage tank, a superheater, a booster compressor, an evaporator, a preheater, a boiler feedwater heater, and a high-temperature water storage tank. The steam compressor is connected to the gas inlet of the steam-molten salt heat exchanger. High-temperature steam from the boiler enters the steam compressor, is pressurized, and then enters the steam-molten salt heat exchanger. The molten salt inlet of the steam-molten salt heat exchanger is connected to the low-temperature molten salt storage tank via a low-temperature molten salt pump. The molten salt outlet of the steam-molten salt heat exchanger is connected to the high-temperature molten salt storage tank. The liquid outlet of the steam-molten salt heat exchanger is connected to the boiler feedwater heater. The outlet of the boiler feedwater heater is connected to the high-temperature water storage tank via a thermal storage switching valve. When the unit is performing deep peak-shaving energy storage, the high-temperature steam from the boiler and the low-temperature molten salt in the steam-molten salt heat exchanger... The high-temperature molten salt formed after heat exchange in the steam-molten salt heat exchanger flows into the high-temperature molten salt storage tank for storage. The saturated water condensed after steam heat exchange enters the boiler feedwater heater and the boiler deaerator water for further heat exchange, and then is introduced into the high-temperature water storage tank through the heat storage switching valve. The high-temperature water storage tank is connected to the preheater, the evaporator, the booster compressor, and the superheater in sequence through the heat release switching valve and the high-temperature water pump. The high-temperature molten salt storage tank is connected to the superheater through the high-temperature molten salt pump. When the unit releases energy at peak, the heat release switching valve is opened, and the hot water from the high-temperature water storage tank is initially pressurized by the high-temperature water pump, enters the preheater and is heated to near the evaporation temperature at this pressure, then enters the evaporator to evaporate into saturated water vapor, and then enters the booster compressor. After being compressed to the boiler steam pressure, it enters the superheater, is heated to superheated temperature, and then flows to the boiler.

[0007] Preferably, the high-temperature steam entering the steam compressor is main steam or reheat steam from the boiler.

[0008] Preferably, the liquid outlet of the steam-molten salt heat exchanger is connected to the boiler feedwater heater via a drain valve, and the saturated water condensed after steam heat exchange enters the boiler feedwater heater through the drain valve.

[0009] Preferably, the boiler deaerator water flows back to the boiler economizer after heat exchange in the boiler feedwater heater.

[0010] Preferably, the top of the high-temperature water storage tank is connected to a nitrogen storage tank to regulate the internal pressure of the high-temperature water storage tank.

[0011] Preferably, the nitrogen storage tank is connected to the nitrogen generator.

[0012] Preferably, the molten salt outlet of the superheater is connected in sequence to the evaporator, the preheater and the low-temperature molten salt storage tank. The high-temperature molten salt flowing into the superheater from the high-temperature molten salt storage tank exchanges heat in the superheater, evaporator and preheater in sequence and then flows into the low-temperature molten salt storage tank for storage.

[0013] Preferably, the high-temperature water pump is connected to the preheater via a feedwater electric heater. Hot water from the high-temperature water storage tank is initially pressurized by the high-pressure water pump and then enters the feedwater electric heater for initial heating. It then flows into the preheater and is heated to the evaporation temperature at this pressure.

[0014] Preferably, a start-up bypass is connected between the inlet of the feedwater electric heater and the steam outlet of the evaporator. The start-up bypass is sequentially connected to a first start-up switching valve, a start-up circulation pump, and a second start-up switching valve. The start-up bypass is used when the water temperature in the high-temperature water storage tank is low and still low after being heated by the feedwater electric heater, and there is a risk of molten salt crystallization when it enters the preheater and exchanges heat with the molten salt. In this case, the first start-up switching valve, the second start-up switching valve, and the start-up circulation pump are opened to extract the liquid high-temperature water inside the evaporator and mix it with the incoming water at the inlet of the feedwater electric heater.

[0015] Preferably, the steam outlet of the superheater is connected to the main steam or reheat steam header of the boiler. The saturated steam flowing out of the evaporator outlet is compressed to the main steam or reheat steam pressure of the boiler by the booster compressor and then enters the superheater. In the superheater, the high-pressure steam heats the steam to superheat, and after reaching the temperature of the main steam or reheat steam of the boiler, it is discharged to the main steam or reheat steam header of the boiler.

[0016] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0017] 1. This system has a steam compressor and a booster compressor installed on the gas inlet side of the steam-molten salt heat exchanger and the superheater, respectively. When the unit is in deep peak-shaving energy storage, the heat release switching valve is closed and the heat storage switching valve is opened. Steam from the main steam or reheat steam header of the boiler is first pressurized by the steam compressor to increase the saturation temperature of the steam, and then enters the steam-molten salt heat exchanger for heat exchange, turning the steam into saturated water, which is stored in the high-temperature water storage tank. The high-temperature molten salt formed by the low-temperature molten salt heat exchange is stored in the high-temperature molten salt storage tank. During off-peak electricity demand, the amount of electricity fed into the grid by thermal power is reduced, while the amount of electricity fed into the grid by photovoltaic and wind power is increased. When the unit is releasing energy at peak demand, the heat storage switching valve is closed and the heat release switching valve is opened. Hot water from the high-temperature water storage tank is initially pressurized by the high-pressure water pump and preheated to the evaporation temperature of this pressure by the preheater before entering the evaporator to evaporate into saturated water. The steam and saturated steam are compressed to the boiler's main steam or reheat steam pressure by a booster compressor and then enter the superheater to be heated to superheat. This superheated steam is then added to the boiler's main steam or reheat steam header, increasing the boiler's steam output and increasing the amount of electricity fed into the grid. This achieves the purpose of deep peak shaving for the unit. Compared with traditional technologies, this avoids the disadvantages of low main steam or reheat steam pressure and low saturation temperature caused by low boiler load, which prevents the effective utilization of latent heat of steam to heat molten salt. It can meet the heat exchange requirements of steam and molten salt under any operating condition during deep peak shaving. At the same time, during heat release, the steam evaporation temperature can be effectively controlled by the combination of a high-temperature water pump and a booster compressor to increase the pressure. This avoids the problem of excessively large heat exchange area and high cost caused by too small a temperature difference at the heat exchange end. It can also meet the requirement of adjusting the steam temperature and pressure according to the boiler load.

[0018] 2. This system can utilize the saturated water condensed from the heat exchange between high-temperature steam and low-temperature molten salt to exchange heat with the boiler deaerator water in the boiler feed water heater. After heat exchange, the boiler deaerator water is used as the economizer water, which can further remove oxygen from the boiler water. The saturated water after heat exchange is stored in a high-temperature water storage tank, realizing dual energy storage of high-temperature molten salt and saturated water, and improving the energy storage capacity of the system during deep peak shaving.

[0019] 3. The flow direction of hot water in the high-temperature water storage tank can be adjusted by the heat storage switching valve and the heat release switching valve. When the unit releases energy at its peak, the stored hot water can be pressurized and heated. After evaporation, it exchanges heat with the stored high-temperature molten salt and is used as high-temperature steam to supplement the boiler's main steam or reheat steam header, thereby improving the boiler's peak capacity, saving heat exchange water, and reducing the heat energy required for heating the heat exchange water and the electrical energy required for heat exchange, making it more energy-efficient and effective. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a connection principle diagram of the molten salt energy storage and peak-shaving system for thermal power plants according to the present invention;

[0022] Explanation of reference numerals in the attached figures:

[0023] 1: Steam compressor; 2: Steam-molten salt heat exchanger; 3: Low-temperature molten salt storage tank; 4: High-temperature molten salt storage tank; 5: Superheater; 6: Boiler booster compressor; 7: Evaporator; 8: Preheater; 9: Boiler feedwater heater; 10: High-temperature water storage tank; 11: Low-temperature molten salt pump; 12: Heat storage switching valve; 13: Heat release switching valve; 14: High-temperature water pump; 15: High-temperature molten salt pump; 16: Steam trap; 17: Nitrogen storage tank; 18: Nitrogen generator; 19: Feedwater electric heater; 20: First start-up switching valve; 21: Start-up circulation pump; 22: Second start-up switching valve. Detailed Implementation

[0024] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0026] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; and they may refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0027] like Figure 1 As shown, this invention provides a molten salt energy storage peak-shaving system for thermal power plants, comprising: a steam compressor 1, a steam-molten salt heat exchanger 2, a low-temperature molten salt storage tank 3, a high-temperature molten salt storage tank 4, a superheater 5, a booster compressor 6, an evaporator 7, a preheater 8, a boiler feedwater heater 9, and a high-temperature water storage tank 10. The steam compressor 1 is connected to the gas inlet of the steam-molten salt heat exchanger 2. High-temperature steam, such as main steam or reheat steam from the boiler, first enters the steam compressor 1 for pressurization before entering the steam-molten salt heat exchanger 2. This avoids the drawback of insufficient latent heat of steam to heat molten salt due to low boiler load causing excessively low pressure or saturation temperature of the main steam or reheat steam. It can meet the heat exchange requirements of steam and molten salt under any operating condition for deep peak shaving.

[0028] The molten salt inlet of the steam-molten salt heat exchanger 2 is connected to the low-temperature molten salt storage tank 3 via a low-temperature molten salt pump 11. The pump 11 pumps the low-temperature molten salt stored in the tank 3 into the steam-molten salt heat exchanger 2 to exchange heat with the main steam or reheat steam from the boiler. The molten salt outlet of the steam-molten salt heat exchanger 2 is connected to the high-temperature molten salt storage tank 4. After heat exchange, the low-temperature molten salt forms high-temperature molten salt which flows into the tank 4 for heat storage. The liquid outlet of the steam-molten salt heat exchanger 2 is connected to the boiler feedwater heater 9. The outlet of the boiler feedwater heater 9 is connected to the boiler feedwater heater 9 via a heat storage switching valve 12. When the unit is in deep peak shaving and energy storage, the high-temperature water storage tank 10 is connected. The high-temperature molten salt formed after the main steam or reheat steam from the boiler exchanges heat with the low-temperature molten salt in the steam-molten salt heat exchanger 2 flows into the high-temperature molten salt storage tank 4 for storage. The saturated water condensed after the steam heat exchange enters the boiler feedwater heater 9 and exchanges heat with the boiler deaerator water. After the temperature is further reduced, it is passed into the high-temperature water storage tank 10 through the heat storage switching valve 12 for storage. The boiler deaerator water after heat exchange flows back to the boiler economizer for use, thereby storing the excess heat energy. During the off-peak electricity demand, the amount of electricity fed into the grid by thermal power is reduced, while the amount of electricity fed into the grid by photovoltaic and wind power is increased.

[0029] The high-temperature water storage tank 10 is connected to the preheater 8, evaporator 7, booster compressor 6, and superheater 5 in sequence through the heat release switching valve 13 and the high-temperature water pump 14. The high-temperature molten salt storage tank 4 is connected to the superheater 5 through the high-temperature molten salt pump 15. When the unit releases energy at its peak, the heat release switching valve 13 is opened. The hot water from the high-temperature water storage tank 10 is initially pressurized by the high-temperature water pump 14 and enters the preheater 8 to be heated to near the evaporation temperature at this pressure. Then, the hot water enters the evaporator and evaporates into saturated steam before entering the booster compressor 6. In the booster compressor 6, the saturated steam is compressed to the pressure of the boiler main steam or reheat steam. The high-pressure steam enters the superheater 5 and is heated to superheat. After reaching the temperature of the boiler main steam or reheat steam, it is discharged to the boiler main steam or reheat steam header, thereby releasing the stored heat energy, increasing the boiler steam output, increasing the grid-connected power output, and thus improving the boiler's peak capacity.

[0030] In this embodiment, the liquid outlet of the steam-molten salt heat exchanger 2 is connected to the boiler feedwater heater 9 through a steam trap 16. The density difference between the steam and the saturated water condensed after heat exchange can be used to allow the saturated water to quickly enter the boiler feedwater heater 9 through the steam trap 16.

[0031] In this embodiment, the top of the high-temperature water storage tank 10 is connected to the nitrogen storage tank 17, and the nitrogen storage tank 17 is connected to the nitrogen generator 18. By adjusting the pressure of the nitrogen storage tank 17 and the nitrogen generator 18, the pressure inside the high-temperature water storage tank 10 can be maintained, and vaporization can be avoided.

[0032] In this embodiment, the molten salt outlet of the superheater 5 is connected in sequence to the evaporator 7, the preheater 8 and the low-temperature molten salt storage tank 3. The high-temperature molten salt in the superheater 5 is pumped into the superheater 5 by the high-temperature molten salt pump 15 through the high-temperature molten salt storage tank 4. After heat exchange in the superheater 5, the evaporator 7 and the preheater 8, it flows into the low-temperature molten salt storage tank 3 for storage.

[0033] In this embodiment, a water supply electric heater 19 is also connected between the high-temperature water pump 14 and the preheater 8. In order to prevent the hot water temperature in the high-temperature water storage tank 10 from being too low, the hot water from the high-temperature water storage tank 10 is initially pressurized by the high-pressure water pump 14 and then enters the water supply electric heater 19 for initial heating before flowing into the preheater 8 to be heated to the evaporation temperature under this pressure.

[0034] In this embodiment, a start-up bypass is connected between the inlet of the water heater 19 and the steam outlet of the evaporator 7. The start-up bypass is connected in sequence to a first start-up switching valve 20, a start-up circulation pump 21, and a second start-up switching valve 22. When the water temperature in the high-temperature water storage tank is low and the water temperature is still low after being heated by the water heater 19, there is a risk that the molten salt will crystallize when it enters the preheater 8 and exchanges heat with the molten salt. The first start-up switching valve 20, the second start-up switching valve 22, and the start-up circulation pump 21 on the start-up bypass are opened to extract the liquid high-temperature water inside the evaporator 7 and mix it with the incoming water at the inlet of the water heater 19 to increase the temperature before entering the preheater 8, thus preventing the molten salt from crystallizing due to excessively low temperature after heat exchange.

[0035] In this embodiment, the steam outlet of the superheater 5 is connected to the main steam or reheat steam header of the boiler. Saturated steam flowing out of the evaporator 7 outlet is compressed to the main steam or reheat steam pressure of the boiler by the booster compressor 6 before entering the superheater 5. In the superheater 5, the high-pressure steam heats the steam to superheat, reaching the main steam or reheat steam temperature of the boiler, and then it is discharged to the main steam or reheat steam header of the boiler, increasing the boiler steam output and thus improving the boiler's peak capacity. By coordinating the high-temperature water pump 14 and the booster compressor 6 to increase the pressure, the steam evaporation temperature can be effectively controlled, avoiding the problem of excessively large heat exchange area and high cost caused by too small a heat exchange temperature difference. It can also meet the requirement of adjusting the steam temperature and pressure according to the boiler load, thus having a higher adaptability to boiler load.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A molten salt energy storage and peak-shaving system for thermal power plants, characterized in that, include: The unit comprises a steam compressor, a steam-molten salt heat exchanger, a low-temperature molten salt storage tank, a high-temperature molten salt storage tank, a superheater, a booster compressor, an evaporator, a preheater, a boiler feedwater heater, and a high-temperature water storage tank. The steam compressor is connected to the gas inlet of the steam-molten salt heat exchanger. High-temperature steam from the boiler enters the steam compressor, is pressurized, and then enters the steam-molten salt heat exchanger. The molten salt inlet of the steam-molten salt heat exchanger is connected to the low-temperature molten salt storage tank via a low-temperature molten salt pump. The molten salt outlet of the steam-molten salt heat exchanger is connected to the high-temperature molten salt storage tank. The liquid outlet of the steam-molten salt heat exchanger is connected to the boiler feedwater heater. The outlet of the boiler feedwater heater is connected to the high-temperature water storage tank via a thermal storage switching valve. When the unit performs deep peak-shaving energy storage, the high-temperature steam from the boiler exchanges heat with the low-temperature molten salt in the steam-molten salt heat exchanger. The formed high-temperature molten salt flows into the high-temperature molten salt storage tank for storage. The saturated water condensed after steam heat exchange enters the boiler feedwater heater and the boiler deaerator water for further heat exchange, and then is introduced into the high-temperature water storage tank through the heat storage switching valve. The high-temperature water storage tank is connected to the preheater, the evaporator, the booster compressor, and the superheater in sequence through the heat release switching valve and the high-temperature water pump. The high-temperature molten salt storage tank is connected to the superheater through the high-temperature molten salt pump. When the unit releases energy at its peak, the heat release switching valve is opened, and the hot water from the high-temperature water storage tank is initially pressurized by the high-temperature water pump, enters the preheater and is heated to near the evaporation temperature at this pressure, then enters the evaporator to evaporate into saturated water vapor, and then enters the booster compressor. After being compressed to the boiler steam pressure, it enters the superheater, is heated to superheated temperature, and then goes to the boiler.

2. The molten salt energy storage and peak-shaving system for thermal power plants according to claim 1, characterized in that, The high-temperature steam entering the steam compressor is either main steam or reheat steam from the boiler.

3. The molten salt energy storage and peak-shaving system for thermal power plants according to claim 1, characterized in that, The liquid outlet of the steam-molten salt heat exchanger is connected to the boiler feedwater heater via a drain valve. The saturated water condensed after steam heat exchange enters the boiler feedwater heater through the drain valve.

4. The molten salt energy storage and peak-shaving system for thermal power plants according to claim 3, characterized in that, The water from the boiler deaerator is returned to the boiler economizer after heat exchange in the boiler feedwater heater.

5. The molten salt energy storage and peak-shaving system for thermal power plants according to claim 1, characterized in that, The top of the high-temperature water storage tank is connected to a nitrogen storage tank to regulate the internal pressure of the high-temperature water storage tank.

6. The molten salt energy storage and peak-shaving system for thermal power plants according to claim 5, characterized in that, The nitrogen storage tank is connected to the nitrogen generator.

7. The molten salt energy storage and peak-shaving system for thermal power plants according to claim 1, characterized in that, The molten salt outlet of the superheater is connected in sequence to the evaporator, the preheater and the low-temperature molten salt storage tank. The high-temperature molten salt flowing into the superheater from the high-temperature molten salt storage tank exchanges heat in the superheater, evaporator and preheater in sequence before flowing into the low-temperature molten salt storage tank for storage.

8. The molten salt energy storage and peak-shaving system for thermal power plants according to claim 1, characterized in that, The high-temperature water pump is connected to the preheater via a feedwater electric heater. Hot water from the high-temperature water storage tank is initially pressurized by the high-temperature water pump and then enters the feedwater electric heater for initial heating. It then flows into the preheater and is heated to the evaporation temperature at this pressure.

9. The molten salt energy storage and peak-shaving system for thermal power plants according to claim 8, characterized in that, A start-up bypass is connected between the inlet of the feedwater electric heater and the steam outlet of the evaporator. The start-up bypass is sequentially connected to a first start-up switching valve, a start-up circulation pump, and a second start-up switching valve. The start-up bypass is used when the water temperature in the high-temperature water storage tank is low and still low after being heated by the feedwater electric heater, and there is a risk of molten salt crystallization when it enters the preheater and exchanges heat with molten salt. In this case, the first start-up switching valve, the second start-up switching valve, and the start-up circulation pump are opened to extract the liquid high-temperature water inside the evaporator and mix it with the incoming water at the inlet of the feedwater electric heater.

10. The molten salt energy storage and peak-shaving system for thermal power plants according to claim 1, characterized in that, The steam outlet of the superheater is connected to the main steam or reheat steam header of the boiler. The saturated steam flowing out of the evaporator outlet is compressed to the main steam or reheat steam pressure of the boiler by the booster compressor and then enters the superheater. In the superheater, the high-pressure steam heats the steam to superheat, and after reaching the main steam or reheat steam temperature of the boiler, it is discharged to the main steam or reheat steam header of the boiler.

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