Deep peak regulation system provided with steam ejector and heat storage device and operation method

Abstract

The invention discloses a deep peak regulation system provided with a steam ejector and a heat storage device and an operation method. The deep peak regulation system comprises a coal-fired power generation system, a heat storage loop and a steam ejector loop. When load rising wet state is converted into dry state, recirculating water separated by a boiler steam-water separator is heated through fused salt and mixed with main steam, meanwhile, high-pressure heater feed water is bypassed, steam extraction flow of a steam turbine is reduced, power capability of the steam turbine is rapidly increased, and the temperature of the feed water is reduced due to reduction of the recirculating water and the high-pressure heater steam extraction. The heat storage loop and the steam ejector loop are used for storing energy, water is heated, the enthalpy of an inlet of the water cooling wall is reduced, and rapid state transition is achieved; and when the load reduction dry state is converted into the wet state, the molten salt is heated by bypass reheat steam, the steam is recycled into the steam storage tank, and the output power of the unit is rapidly reduced. Through steam-water working medium circulation path reconstruction and fused salt / steam and other multi-medium energy storage cross-space-time regulation and control, ultra-low load dry-wet rapid state transition of the coal-fired unit is achieved, and the deep peak regulation capacity of the unit is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal-fired power generation, and in particular relates to a deep peak regulation system configured with a steam ejector and a heat storage device and an operation method thereof. Background Art

[0002] With the rapid increase in installed capacity of renewable energy sources such as solar energy and wind energy, their volatility, intermittency and unpredictability have brought huge challenges to the stable and safe operation of the power grid. As the development trend of coal-fired power generation technology, supercritical units are the mainstay of my country's coal-fired power generation, accounting for about 60% of the total installed capacity of coal-fired power. They are also the main models used in my country to absorb renewable energy and regulate peak and frequency. However, under deep peak-shaving conditions, supercritical units inevitably experience wet operation, and the transition process takes a long time and is difficult to control, which seriously limits the deep peak-shaving capability of the units.

[0003] A steam ejector is a device that can use a high-pressure energy flow to eject another low-pressure energy flow. It can increase the pressure of low-pressure steam, increase the dryness of the working fluid, have high ejection efficiency, and reduce energy loss. External heat storage devices can be used to store and release energy across time and space within coal-fired units, and use the energy stored in the load reduction process for the rapid load increase process, breaking through the shackles of large delays and large inertia of the boiler, breaking the constraints of peak-shaving and frequency regulation of coal-fired units, and further improving the deep peak-shaving capabilities of the units. Configuring steam ejectors and heat storage devices in coal-fired power generation thermal systems is a highly potential technical route that can achieve wide-range flexible peak-shaving of supercritical units. Summary of the invention

[0004] In order to solve the problem of insufficient flexibility in deep peak-shaving operation of supercritical coal-fired power generation units, the purpose of the present invention is to provide a deep peak-shaving system and an operating method equipped with a steam ejector and a heat storage device. The steam ejector and the heat storage device are equipped to achieve ultra-low load dry-wet rapid transition through thermal system configuration design, storage / release heat circuit switching, and steam ejection: when the load is increased and the wet state is converted to the dry state, the molten salt is used to release heat to heat the boiler recirculation working medium, increase the main steam flow, and at the same time, the bypass feed water is used to reduce the extraction steam flow, further increase the working capacity of the turbine, and achieve rapid power increase. At the same time, the molten salt / steam energy storage is used in stages to heat the feed water, reduce the water-cooled wall inlet enthalpy, and achieve rapid transition; when the load is reduced and the dry state is converted to the wet state, the bypass reheat steam is used to heat the molten salt, and the heated steam is partially stored in the steam storage tank, and partially used to eject the exhaust steam of the intermediate pressure cylinder to reduce the humidity of the low pressure cylinder at the last stage, so as to quickly reduce the output power of the unit and realize efficient storage of molten salt / steam energy.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A deep peak-shaving system equipped with a steam ejector and a heat storage device, comprising a coal-fired power generation system, a heat storage loop and a steam ejector loop;

[0007] The coal-fired power generation system comprises a boiler 1, a steam turbine high-pressure cylinder 7, a steam turbine medium-pressure cylinder 8, a steam turbine low-pressure cylinder 9, a generator 10, a condenser 11, a condensate pump 12, a low-pressure heater 13, a deaerator 14, a feedwater pump 15, a high-pressure heater 16, a feedwater bypass regulating valve 17, a feedwater bypass pump 18, a feedwater bypass heater 19 and an medium-pressure cylinder outlet regulating valve 33; the main steam outlet of the boiler 1 is connected to the steam inlet of the steam turbine high-pressure cylinder 7 through a pipeline, the steam extraction outlet of the steam turbine high-pressure cylinder 7 is connected to the steam inlet of the high-pressure heater 16 through a pipeline, and the steam turbine high-pressure cylinder 7 is connected to the steam outlet of the steam turbine high-pressure cylinder 7 through a pipeline. The reheated steam of cylinder 7 enters the boiler 1 and is connected to the steam inlet of the turbine intermediate pressure cylinder 8. The extraction steam of the turbine intermediate pressure cylinder 8 is connected to the steam inlet of the deaerator 14 through a pipeline. The steam outlet of the turbine intermediate pressure cylinder 8 is connected to the steam inlet of the turbine low pressure cylinder 9 through the intermediate pressure cylinder outlet regulating valve 33. The extraction steam outlet of the turbine low pressure cylinder 9 is connected to the steam inlet of the low pressure heater 13 through a pipeline. The steam outlet of the turbine low pressure cylinder 9 is connected to the condenser 11. The condensate working medium outlet of the condenser 11 is connected to the condensate working medium inlet of the low pressure heater 13 through the condensate pump 12. The condensate outlet of the low-pressure heater 13 is connected to the feed water inlet of the deaerator 14, the feed water outlet of the deaerator 14 is connected to the feed water inlet of the high-pressure heater 16 through the feed water pump 15, the feed water outlet of the high-pressure heater 16 is connected to the boiler 1 through the molten salt-feed water heat exchanger 26 of the heat storage circuit, and the bypass feed water outlet of the deaerator 14 flows through the feed water bypass regulating valve 17, the feed water bypass pump 18 and the feed water bypass heater 19 respectively, and then mixes with the feed water at the water outlet of the high-pressure heater 16; the boiler 1 is provided with a recirculation system, and the recirculation system includes Steam-water separator 2, separator water storage tank 3, recirculation pump 4, recirculation water first regulating valve 5 and recirculation water second regulating valve 6; saturated water separated by steam-water separator 2 enters separator water storage tank 3, and recirculation water at the outlet of separator water storage tank 3 is divided into two paths after passing through recirculation pump 4, one path passes through recirculation regulating valve 5 and is mixed with turbine feed water before entering boiler 1, and the other path passes through recirculation water second regulating valve 6 and enters molten salt-recirculation water heat exchanger 25 of heat storage circuit; turbine high-pressure cylinder 7, turbine intermediate-pressure cylinder 8 and turbine low-pressure cylinder 9 are coaxial and connected to the power grid through generator 10;

[0008] The heat storage circuit includes a steam-molten salt heat exchanger 20, a hot tank 21, a hot tank outlet regulating valve 22, a hot tank outlet pump 23, a molten salt-recirculating water heat exchanger 25, a molten salt-feed water heat exchanger 26, a cold tank 27, a cold tank outlet regulating valve 28, a cold tank outlet pump 29 and pipelines connecting various types of equipment; the molten salt at the outlet of the hot tank 21 is connected to the molten salt inlet of the molten salt-recirculating water heat exchanger 25 through the hot tank outlet regulating valve 22 and the hot tank outlet pump 23, and the boiler recirculating water is connected to the molten salt through the second recirculating water regulating valve 6. -The working medium inlet of the recirculating water heat exchanger 25 is connected, the steam outlet of the molten salt-recirculating water heat exchanger 25 is connected to the steam inlet of the turbine high-pressure cylinder 7, the molten salt outlet of the molten salt-recirculating water heat exchanger 25 flows through the molten salt-feed water heat exchanger 26, and is connected to the molten salt inlet of the cold tank 27, the molten salt outlet of the cold tank 27 is connected to the molten salt inlet of the steam-molten salt heat exchanger 20 through the cold tank outlet regulating valve 28 and the cold tank outlet pump 29, and the molten salt outlet of the steam-molten salt heat exchanger 20 is connected to the molten salt inlet of the hot tank 21;

[0009] The steam ejector circuit includes a reheat steam bypass regulating valve 24, a first steam ejector 31, a first regulating valve 30 of the first steam ejector, a second regulating valve 32 of the first steam ejector, a low-pressure steam storage tank extraction valve 34, a high-pressure steam storage tank 35, a high-pressure steam storage tank regulating valve 36, a low-pressure steam storage tank 37, a low-pressure steam storage tank regulating valve 38 and a second steam ejector 39; the bypass reheat steam flows through the steam-molten salt heat exchanger 20 and is collected in the high-pressure steam storage tank 35, and part of the bypass reheat steam flows through the first regulating valve 30 of the first steam ejector and enters the first steam ejector 3 1, the exhaust steam at the outlet of the intermediate pressure cylinder 8 of the ejector steam turbine flows through the second regulating valve 32 of the first steam ejector and enters the first steam ejector 31, the working medium at the outlet of the first steam ejector 31 enters the low pressure cylinder 9 of the steam turbine, the extraction steam of the low pressure cylinder 9 of the steam turbine flows through the extraction valve 34 of the low pressure steam storage tank and is stored in the low pressure steam storage tank 37, the steam at the outlet of the high pressure steam storage tank 35 flows through the regulating valve 36 of the high pressure steam storage tank, the low pressure steam from the low pressure steam storage tank 37 flowing through the regulating valve 38 of the low pressure steam storage tank is ejected, and the working medium at the outlet of the second steam ejector 39 heats the feed water in the feed water bypass heater 19 and then returns to the deaerator 14.

[0010] The operating method of the deep peak regulation system equipped with a steam ejector and a heat storage device is as follows: when the coal-fired power generation system increases load and switches from a wet state to a dry state, the first recirculating water regulating valve 5 is closed, the second recirculating water regulating valve 6 is opened, the reheat steam bypass regulating valve 24, the first steam ejector first regulating valve 30, and the second steam ejector second regulating valve 32 are closed, the hot tank outlet regulating valve 22 is opened, and the cold tank outlet regulating valve 28 is closed. The hot molten salt flows through the molten salt-recirculating water heat exchanger 25 to heat the recirculating water and then converge to the main steam, thereby increasing the steam flow rate at the inlet of the high-pressure cylinder 7 of the steam turbine and improving the working capacity; the low-pressure steam storage tank extraction valve 34 is closed, the high-pressure steam storage tank regulating valve 36 and the low-pressure steam storage tank regulating valve 38 are opened, and the feed water bypass regulating valve 17 is opened. After the feed water bypass, the steam extraction flow rate of the steam turbine high-pressure booster is reduced, and the working medium flow rate is increased, thereby improving the working capacity; the temperature is reduced after the feed water bypass, and the working medium at the steam ejector outlet is heated in the feed water bypass heater 19. The heat is collected into the main water supply line and further heated in the molten salt-feedwater heat exchanger 26, thereby reducing the enthalpy deficit of the working medium at the water wall inlet and realizing a rapid conversion from wet to dry state. When the coal-fired power generation system is operated from dry state to wet state with load reduction, the second regulating valve 6 of the recirculating water is closed, the first regulating valve 5 of the recirculating water is opened, and the recirculating water separated by the steam-water separator 2 enters the boiler 1, the hot tank outlet regulating valve 22 is closed, the cold tank outlet regulating valve 28 is opened, and the reheat steam bypass regulating valve 2 is opened. 4. Bypass reheat steam to heat molten salt and reduce the working fluid flow of the medium and low pressure cylinders of the steam turbine to achieve rapid load reduction. Open the first regulating valve 30 of the first steam ejector, the second regulating valve 32 of the first steam ejector, and the regulating valve 33 at the outlet of the medium pressure cylinder. The heated reheat steam is ejected from the medium pressure cylinder 8 of the steam turbine to exhaust steam. Regulate the second regulating valve 32 of the first steam ejector and the regulating valve 33 at the outlet of the medium pressure cylinder to increase the inlet pressure of the low pressure cylinder 9 of the steam turbine and reduce the humidity of the last stage of the low pressure cylinder 9 of the steam turbine.

[0011] Compared with the prior art, the present invention has the following advantages:

[0012] 1. The present invention provides a deep peak regulation system equipped with a steam ejector and a heat storage device. When the load is increased and the wet state is converted to the dry state, the molten salt is used to release heat to heat the boiler recirculation medium to increase the main steam flow rate. At the same time, the bypass feed water reduces the extraction steam flow rate, further increasing the working capacity of the turbine and realizing a rapid increase in power. At the same time, the molten salt / steam energy storage is used in stages to heat the feed water, reduce the water wall inlet under-enthalpy, and realize a rapid conversion.

[0013] 2. The present invention provides a deep peak-shaving system equipped with a steam ejector and a heat storage device. When the load is reduced and the dry state is converted to the wet state, the bypass reheat steam heats the molten salt. Part of the heated steam is stored in the steam storage tank, and part is used to eject the exhaust steam from the intermediate pressure cylinder to reduce the humidity of the last stage of the low pressure cylinder, thereby quickly reducing the output power of the coal-fired power generation system and realizing efficient storage of molten salt / steam energy.

[0014] 3. The present invention configures a steam ejector and a heat storage device in coal-fired power generation, and provides an operation method of a coupling system based on the thermal system configuration design, storage / release heat circuit switching, steam ejection, etc., and realizes ultra-low load dry-wet rapid transition through reconstruction of the flow path of steam-water working medium, cross-temporal and spatial control of multi-media energy storage such as molten salt / steam, and cascade utilization of multi-taste energy, thus breaking through the constraints of large delay and large inertia of the boiler and improving the deep peak regulation capability of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of a deep peak-shaving system equipped with a steam ejector and a heat storage device. DETAILED DESCRIPTION

[0016] The present invention is further described below in conjunction with the accompanying drawings and implementation modes.

[0017] like Figure 1 As shown, a deep peak-shaving system equipped with a steam ejector and a heat storage device comprises a coal-fired power generation system, a heat storage loop and a steam ejector loop;

[0018] Figure 1 The coal-fired power generation system includes: a boiler 1, a high-pressure cylinder 7 of a steam turbine, an intermediate-pressure cylinder 8, a low-pressure cylinder 9, a generator 10, a condenser 11, a condensate pump 12, a low-pressure heater 13, a deaerator 14, a feedwater pump 15, a high-pressure heater 16, a feedwater bypass regulating valve 17, a feedwater bypass pump 18, a feedwater bypass heater 19, and an intermediate-pressure cylinder outlet regulating valve 33. The boiler is provided with a steam-water separator 2, a separator water storage tank 3, a recirculation pump 4, a first recirculation water regulating valve 5, and a second recirculation water regulating valve 6; the heat storage circuit includes: a steam-molten salt heat exchanger 20, a hot tank 21, and a hot tank outlet The steam ejector circuit includes: a reheat steam bypass regulating valve 24, a first steam ejector 31, a first regulating valve 30 of the first steam ejector, a second regulating valve 32 of the first steam ejector, a low-pressure steam storage tank extraction valve 34, a high-pressure steam storage tank 35, a high-pressure steam storage tank regulating valve 36, a low-pressure steam storage tank 37, a low-pressure steam storage tank regulating valve 38, and a second steam ejector 39;

[0019] like Figure 1As shown, the main steam outlet of the boiler 1 is connected to the steam inlet of the high-pressure cylinder 7 of the steam turbine through a pipeline, the extraction steam outlet of the high-pressure cylinder 7 of the steam turbine is connected to the steam inlet of the high-pressure heater 16 through a pipeline, the reheated steam of the high-pressure cylinder 7 of the steam turbine enters the boiler 1 and is connected to the steam inlet of the intermediate-pressure cylinder 8 of the steam turbine, the extraction steam of the intermediate-pressure cylinder 8 of the steam turbine is connected to the steam inlet of the deaerator 14 through a pipeline, the steam outlet of the intermediate-pressure cylinder 8 of the steam turbine is connected to the steam inlet of the low-pressure cylinder 9 of the steam turbine through the intermediate-pressure cylinder outlet regulating valve 33, the extraction steam outlet of the low-pressure cylinder 9 of the steam turbine is connected to the steam inlet of the low-pressure heater 13 through a pipeline, the steam outlet of the low-pressure cylinder 9 of the steam turbine is connected to the condenser 11, the condensate working medium outlet of the condenser 11 is connected to the condensate working medium inlet of the low-pressure heater 13 through the condensate pump 12, and the condensate working medium outlet of the low-pressure heater 13 is connected to the deaerator The feed water working medium inlet of the oxygenator 14 is connected, the feed water working medium outlet of the deaerator 14 is connected to the feed water working medium inlet of the high-pressure heater 16 through the feed water pump 15, the feed water working medium outlet of the high-pressure heater 16 is connected to the boiler 1 through the molten salt-feed water heat exchanger 26 of the heat storage circuit, and the bypass feed water working medium outlet of the deaerator 14 flows through the feed water bypass regulating valve 17, the feed water bypass pump 18 and the feed water bypass heater 19 respectively, and then mixes with the feed water working medium outlet of the high-pressure heater 16; the boiler 1 is provided with a recirculation system, the saturated water separated by the steam-water separator 2 enters the separator water storage tank 3, and the outlet recirculating water of the separator water storage tank 3 is divided into two paths after passing through the recirculation pump 4, one path passes through the recirculation regulating valve 5 and is mixed with the turbine feed water before entering the boiler 1; the turbine high-pressure cylinder 7, the turbine intermediate-pressure cylinder 8 and the turbine low-pressure cylinder 9 are coaxial and connected to the power grid through the generator 10.

[0020] like Figure 1 As shown, the molten salt at the outlet of the hot tank 21 is connected to the molten salt inlet of the molten salt-recirculating water heat exchanger 25 through the hot tank outlet regulating valve 22 and the hot tank outlet pump 23, the boiler recirculating water is connected to the working medium inlet of the molten salt-recirculating water heat exchanger 25 through the second recirculating water regulating valve 6, the steam outlet of the molten salt-recirculating water heat exchanger 25 is connected to the steam inlet of the turbine high-pressure cylinder 7, the molten salt outlet of the molten salt-recirculating water heat exchanger 25 flows through the molten salt-feed water heat exchanger 26, and is connected to the molten salt inlet of the cold tank 27, the molten salt outlet of the cold tank 27 is connected to the molten salt inlet of the steam-molten salt heat exchanger 20 through the cold tank outlet regulating valve 28 and the cold tank outlet pump 29, and the molten salt outlet of the steam-molten salt heat exchanger 20 is connected to the molten salt inlet of the hot tank 21.

[0021] like Figure 1As shown, the bypass reheated steam flows through the steam-molten salt heat exchanger 20 and is collected in the high-pressure steam storage tank 35. Part of the bypass reheated steam flows through the first regulating valve 30 of the first steam ejector and enters the first steam ejector 31. The exhaust steam at the outlet of the intermediate-pressure cylinder 8 of the ejected steam turbine flows through the second regulating valve 32 of the first steam ejector and enters the first steam ejector 31. The working medium at the outlet of the first steam ejector 31 enters the low-pressure cylinder 9 of the steam turbine. The extraction steam of the low-pressure cylinder 9 of the steam turbine flows through the extraction valve 34 of the low-pressure steam storage tank and is stored in the low-pressure steam storage tank 37. The steam at the outlet of the high-pressure steam storage tank 35 flows through the regulating valve 36 of the high-pressure steam storage tank, and the low-pressure steam from the low-pressure steam storage tank 37 flowing through the regulating valve 38 of the low-pressure steam storage tank is ejected. The working medium at the outlet of the second steam ejector 39 heats the feed water in the feed water bypass heater 19 and then returns to the deaerator 14.

[0022] The present invention provides an operating method of the deep peak regulation system equipped with a steam ejector and a heat storage device as follows:

[0023] When the coal-fired power generation system is loaded and switched from a wet state to a dry state, the first regulating valve 5 of the recirculating water is closed, the second regulating valve 6 of the recirculating water is opened, the reheat steam bypass regulating valve 24, the first regulating valve 30 of the first steam ejector, and the second regulating valve 32 of the first steam ejector are closed, the hot tank outlet regulating valve 22 is opened, and the cold tank outlet regulating valve 28 is closed. The hot molten salt flows through the molten salt-recirculating water heat exchanger 25 to heat the recirculating water and then converges to the main steam, increasing the steam flow at the inlet of the high-pressure cylinder 7 of the steam turbine and improving the performance. power; close the low-pressure steam storage tank extraction valve 34, open the high-pressure steam storage tank regulating valve 36 and the low-pressure steam storage tank regulating valve 38, open the feedwater bypass regulating valve 17, after the feedwater bypass, the steam extraction flow of the turbine high-pressure booster is reduced, and the working medium flow is increased, thereby improving the working capacity; after the feedwater bypass, the temperature is reduced, and it is heated by the outlet working medium of the steam ejector in the feedwater bypass heater 19, merged into the main feedwater path, and further heated by flowing through the molten salt-feedwater heat exchanger 26, thereby reducing the working medium under-enthalpy at the water-cooled wall inlet, thereby realizing a rapid conversion from wet state to dry state;

[0024] When the coal-fired power generation system switches from a dry state to a wet state during load reduction, the second regulating valve 6 of the recirculating water is closed, the first regulating valve 5 of the recirculating water is opened, and the recirculating water separated by the steam-water separator 2 enters the boiler 1. The hot tank outlet regulating valve 22 is closed, the cold tank outlet regulating valve 28 is opened, the reheat steam bypass regulating valve 24 is opened, the bypass reheat steam heats the molten salt, and the working medium flow of the medium and low pressure cylinders of the steam turbine is reduced at the same time to achieve rapid load reduction. The first regulating valve 30 of the first steam ejector, the second regulating valve 32 of the first steam ejector, and the regulating valve 33 of the outlet of the medium pressure cylinder of the steam turbine are opened, and the heated reheat steam is ejected into the medium pressure cylinder 8 to exhaust steam. The second regulating valve 32 of the first steam ejector and the regulating valve 33 of the outlet of the medium pressure cylinder are adjusted to increase the inlet pressure of the low pressure cylinder 9 of the steam turbine and reduce the humidity of the last stage of the low pressure cylinder 9 of the steam turbine.

Claims

1. A deep peak shaving system equipped with a steam ejector and a heat storage device, characterized in that: It includes coal-fired power generation system, heat storage loop and steam ejector loop; The coal-fired power generation system comprises a boiler (1), a high-pressure cylinder (7) of a steam turbine, an intermediate-pressure cylinder (8) of a steam turbine, a low-pressure cylinder (9) of a steam turbine, a generator (10), a condenser (11), a condensate pump (12), a low-pressure heater (13), a deaerator (14), a feedwater pump (15), a high-pressure heater (16), a feedwater bypass regulating valve (17), a feedwater bypass pump (18), a feedwater bypass heater (19) and an intermediate-pressure cylinder outlet regulating valve (33); the main steam outlet of the boiler (1) is connected to the steam inlet of the high-pressure cylinder (7) of the steam turbine via a pipeline, and the extraction steam outlet of the high-pressure cylinder (7) of the steam turbine is connected to the steam inlet of the high-pressure heater (16) via a pipeline. The reheated steam of the high-pressure cylinder (7) of the steam turbine enters the boiler (1) and is connected to the steam inlet of the intermediate-pressure cylinder (8) of the steam turbine. The extraction steam of the intermediate-pressure cylinder (8) of the steam turbine is connected to the steam inlet of the deaerator (14) through a pipeline. The steam outlet of the intermediate-pressure cylinder (8) of the steam turbine is connected to the steam inlet of the low-pressure cylinder (9) of the steam turbine through an intermediate-pressure cylinder outlet regulating valve (33). The extraction steam outlet of the low-pressure cylinder (9) of the steam turbine is connected to the steam inlet of the low-pressure heater (13) through a pipeline. The steam outlet of the low-pressure cylinder (9) of the steam turbine is connected to the condenser (11). The condensate outlet of the condenser (11) is connected to the condensate inlet of the low-pressure heater (13) through a condensate pump (12). The condensate outlet of the low-pressure heater (13) is connected to the feed water inlet of the deaerator (14), the feed water outlet of the deaerator (14) is connected to the feed water inlet of the high-pressure heater (16) through a feed water pump (15), the feed water outlet of the high-pressure heater (16) is connected to the boiler (1) through a molten salt-feed water heat exchanger (26) of the heat storage circuit, and the bypass feed water outlet of the deaerator (14) flows through a feed water bypass regulating valve (17), a feed water bypass pump (18) and a feed water bypass heater (19) respectively, and then mixes with the feed water at the water outlet of the high-pressure heater (16); the boiler (1) is provided with a recirculation system, and the recirculation system includes a steam-water A separator (2), a separator water storage tank (3), a recirculation pump (4), a first recirculation water regulating valve (5) and a second recirculation water regulating valve (6); saturated water separated by the steam-water separator (2) enters the separator water storage tank (3), and the outlet recirculation water of the separator water storage tank (3) is divided into two paths after passing through the recirculation pump (4), one path passes through the recirculation regulating valve (5) and is mixed with the turbine feed water before entering the boiler (1), and the other path passes through the second recirculation water regulating valve (6) and enters the molten salt-recirculation water heat exchanger (25) of the heat storage circuit; the turbine high-pressure cylinder (7), the turbine intermediate-pressure cylinder (8) and the turbine low-pressure cylinder (9) are coaxial and connected to the power grid through the generator (10); The heat storage circuit comprises a steam-molten salt heat exchanger (20), a hot tank (21), a hot tank outlet regulating valve (22), a hot tank outlet pump (23), a molten salt-recirculating water heat exchanger (25), a molten salt-feed water heat exchanger (26), a cold tank (27), a cold tank outlet regulating valve (28), a cold tank outlet pump (29) and pipelines connecting various types of equipment; the molten salt at the outlet of the hot tank (21) is connected to the molten salt inlet of the molten salt-recirculating water heat exchanger (25) through the hot tank outlet regulating valve (22) and the hot tank outlet pump (23), and the boiler recirculating water is connected to the boiler through the second recirculating water regulating valve (6). The working medium inlet of the molten salt-recirculating water heat exchanger (25) is connected, the steam outlet of the molten salt-recirculating water heat exchanger (25) is connected to the steam inlet of the turbine high-pressure cylinder (7), the molten salt outlet of the molten salt-recirculating water heat exchanger (25) flows through the molten salt-feed water heat exchanger (26) and is connected to the molten salt inlet of the cold tank (27), the molten salt outlet of the cold tank (27) is connected to the molten salt inlet of the steam-molten salt heat exchanger (20) through the cold tank outlet regulating valve (28) and the cold tank outlet pump (29), and the molten salt outlet of the steam-molten salt heat exchanger (20) is connected to the molten salt inlet of the hot tank (21); The steam ejector circuit comprises a reheat steam bypass regulating valve (24), a first steam ejector (31), a first regulating valve (30) of the first steam ejector, a second regulating valve (32) of the first steam ejector, a low-pressure steam storage tank extraction valve (34), a high-pressure steam storage tank (35), a high-pressure steam storage tank regulating valve (36), a low-pressure steam storage tank (37), a low-pressure steam storage tank regulating valve (38) and a second steam ejector (39); the bypass reheat steam flows through the steam-molten salt heat exchanger (20) and is collected in the high-pressure steam storage tank (35), and part of the bypass reheat steam flows through the first regulating valve (30) of the first steam ejector and enters the first steam ejector (31). The exhaust steam at the outlet of the intermediate pressure cylinder (8) of the ejector steam turbine flows through the second regulating valve (32) of the first steam ejector and enters the first steam ejector (31). The working medium at the outlet of the first steam ejector (31) enters the low pressure cylinder (9) of the steam turbine. The extraction steam of the low pressure cylinder (9) of the steam turbine flows through the extraction valve (34) of the low pressure steam storage tank and is stored in the low pressure steam storage tank (37). The steam at the outlet of the high pressure steam storage tank (35) flows through the regulating valve (36) of the high pressure steam storage tank, ejecting the low pressure steam from the low pressure steam storage tank (37) and flowing through the regulating valve (38) of the low pressure steam storage tank. The working medium at the outlet of the second steam ejector (39) heats the feed water in the feed water bypass heater (19) and then returns to the deaerator (14).

2. The method for operating a deep peak shaving system equipped with a steam ejector and a heat storage device according to claim 1, characterized in that: When the coal-fired power generation system is operated from a wet state to a dry state, the first regulating valve (5) of the recirculating water is closed, the second regulating valve (6) of the recirculating water is opened, the reheat steam bypass regulating valve (24), the first regulating valve (30) of the first steam ejector, and the second regulating valve (32) of the first steam ejector are closed, the hot tank outlet regulating valve (22) is opened, and the cold tank outlet regulating valve (28) is closed. The hot molten salt flows through the molten salt-recirculating water heat exchanger (25) to heat the recirculating water and then merges into the main steam, thereby increasing the steam pressure. The steam flow at the inlet of the high-pressure cylinder (7) of the steam turbine is increased to improve the working capacity; the low-pressure steam storage tank extraction valve (34) is closed, the high-pressure steam storage tank regulating valve (36) and the low-pressure steam storage tank regulating valve (38) are opened, and the feed water bypass regulating valve (17) is opened. After the feed water bypass, the steam flow of the high-pressure steam turbine is reduced, and the flow of the working medium is increased to improve the working capacity; after the feed water bypass, the temperature is reduced, and the steam is heated by the outlet working medium of the steam ejector in the feed water bypass heater (19), and then flows into the main feed water path and flows through the molten salt-feed water exchanger. The reheated water is further heated in the heat exchanger (26), thereby reducing the enthalpy deficit of the working medium at the water wall inlet, and realizing a rapid conversion from a wet state to a dry state. When the coal-fired power generation system is operated from a dry state to a wet state at a reduced load, the second recirculating water regulating valve (6) is closed, the first recirculating water regulating valve (5) is opened, and the recirculating water separated by the steam-water separator (2) enters the boiler (1). The hot tank outlet regulating valve (22) is closed, the cold tank outlet regulating valve (28) is opened, and the reheat steam bypass regulating valve (24) is opened to bypass the reheat steam heating. Hot molten salt, while reducing the working fluid flow of the medium and low pressure cylinders of the steam turbine, achieving rapid load reduction, opening the first regulating valve (30) of the first steam ejector, the second regulating valve (32) of the first steam ejector, and the medium pressure cylinder outlet regulating valve (33), and ejecting the heated reheated steam to exhaust steam from the medium pressure cylinder (8) of the steam turbine, regulating the second regulating valve (32) of the first steam ejector and the medium pressure cylinder outlet regulating valve (33), increasing the inlet pressure of the low pressure cylinder (9) of the steam turbine, and reducing the final humidity of the low pressure cylinder (9) of the steam turbine.

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