A combined cycle coupled molten salt energy storage deep peak shaving system and its method

Abstract

The present invention relates to a combined cycle coupled molten salt energy storage deep peak shaving system and a method thereof. The system includes: a circulating power generation mechanism, including a steam turbine unit and a waste heat boiler unit. The steam generated by the waste heat boiler unit enters the steam turbine unit to do work and generate electricity. The waste heat boiler unit includes a feed water heater; a molten salt energy storage mechanism, including a low-temperature molten salt storage tank, a high-temperature molten salt storage tank, a primary molten salt heater, a secondary molten salt heater, a low-temperature molten salt pump, a high-temperature molten salt pump, a high-pressure steam superheater, a high-pressure steam generator, a low-pressure steam superheater, a low-pressure steam generator, and a first feed water pump. The technical solution of the present invention realizes the cascaded and efficient utilization of the waste heat of high-temperature flue gas and the heat of high-temperature molten salt, greatly reduces the heat transfer temperature difference, reduces the irreversible loss, and also increases the output of high-quality steam. After the steam is output, it continues to act on the steam turbine unit, and also greatly improves the power generation capacity of the steam turbine unit.

Description

Technical Field

[0001] The present invention relates to the technical field of energy conservation and emission reduction, and particularly to a combined cycle coupled molten salt energy storage deep peak shaving system and its method. Background Art

[0002] The gas-steam combined cycle method has become the fastest-growing power generation form internationally due to its advantages such as high power generation efficiency, short construction period, and convenient operation, which also has great guiding significance for the current power structure adjustment in China. However, when the combined cycle unit participates in power grid peak shaving, with the fluctuations of the power consumption load and new energy power, the operating load fluctuates frequently, resulting in a significant reduction in the efficiency of the combined cycle unit. For example, when the unit operates at low load compared with full load, when the unit load rate is 60%, the heat consumption increases by 8%, and when the unit load rate is 40%, the heat consumption will increase by 20%. Therefore, it is crucial to integrate an energy storage device in the combined cycle system to ensure that the unit can still operate at a relatively high load when participating in power peak shaving, improving the efficiency and flexibility of the overall system.

[0003] Therefore, molten salt energy storage technology has developed into the most mainstream high-temperature heat storage technology internationally due to its advantages such as low cost, high heat capacity, and good safety. Using molten salt energy storage technology to solve the problem of insufficient power peak shaving capacity of combined cycle units is a very promising technical application method. In related technologies, for peak shaving in the field of coupling molten salt energy storage with flue gas waste heat utilization, high-temperature flue gas directly heats low-temperature molten salt into high-temperature molten salt. However, due to the too large heat transfer temperature difference, serious irreversible losses are generated; and using high-temperature molten salt to produce low-parameter steam for heating also causes high-grade molten salt heat loss. Summary of the Invention

[0004] The purpose of the present invention is to provide a combined cycle coupled molten salt energy storage deep peak shaving system and its method. This system realizes the cascade high-efficient utilization of high-temperature flue gas waste heat and high-temperature molten salt heat, greatly reduces the heat transfer temperature difference, reduces irreversible losses, and also increases the output of high-quality steam. After the steam is output, it continues to act on the steam turbine unit, greatly improving the power generation capacity of the steam turbine unit.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A combined cycle coupled molten salt energy storage deep peak shaving system, comprising:

[0007] A cycle power generation mechanism, including a steam turbine unit and a waste heat boiler unit. The steam generated by the waste heat boiler unit enters the steam turbine unit to do work and generate electricity. The waste heat boiler unit includes a feed water heater;

[0008] Molten salt energy storage mechanism, including a low-temperature molten salt storage tank, a high-temperature molten salt storage tank, a primary molten salt heater, a secondary molten salt heater, a low-temperature molten salt pump, a high-temperature molten salt pump, a high-pressure steam superheater, a high-pressure steam generator, a low-pressure steam superheater, a low-pressure steam generator and a first feed water pump;

[0009] Among them, the molten salt outlet of the low-temperature molten salt storage tank is installed with the low-temperature molten salt pump. The molten salt outlet of the low-temperature molten salt storage tank is connected to the molten salt inlet of the primary molten salt heater. The molten salt outlet of the primary molten salt heater is connected to the molten salt inlet of the secondary molten salt heater. The molten salt outlet of the secondary molten salt heater is connected to the molten salt inlet of the high-temperature molten salt storage tank. The molten salt outlet of the high-temperature molten salt storage tank is installed with the high-temperature molten salt pump and is connected to the molten salt inlet of the high-pressure steam superheater. The molten salt outlet of the high-pressure steam superheater is connected to the molten salt inlet of the high-pressure steam generator. The molten salt outlet of the high-pressure steam generator is connected to the molten salt inlet of the low-pressure steam superheater. The molten salt outlet of the low-pressure steam superheater is connected to the molten salt inlet of the low-pressure steam generator. The molten salt outlet of the low-pressure steam generator is connected to the molten salt inlet of the low-temperature molten salt storage tank;

[0010] The feed water outlet of the feed water heater is respectively connected to the feed water inlets of the high-pressure steam generator and the low-pressure steam generator. The feed water inlet of the high-pressure steam generator is installed with the first feed water pump. The steam outlet of the high-pressure steam generator is connected to the steam inlet of the high-pressure steam superheater. The steam outlet of the high-pressure steam superheater is connected to the steam turbine unit to do work and generate electricity. The steam outlet of the low-pressure steam generator is connected to the steam inlet of the low-pressure steam superheater. The steam outlet of the low-pressure steam superheater is connected to the steam turbine unit to do work and generate electricity.

[0011] Preferably, the circulating power generation mechanism further includes a circulating feed water unit, and the circulating feed water unit includes a condensate pump, a deaerator, a condensate storage tank and a circulating water pump. The water outlet of the condensate pump is connected to the water inlet of the condensate storage tank. The water outlet of the condensate storage tank is connected to the water inlet of the deaerator. The water outlet of the condensate storage tank is installed with the circulating water pump. The water outlet of the deaerator is connected to the feed water inlet of the feed water heater.

[0012] Preferably, the circulating feed water unit further includes a condensate pipe and a condenser. The water outlet of the condenser is connected to the water inlet of the deaerator through the condensate pipe, and the condensate pump is installed on the condensate pipe.

[0013] Preferably, the molten salt energy storage mechanism further includes an electric heating type molten salt heater, which is installed at the molten salt outlet of the secondary molten salt heater, and the molten salt outlet of the electric heating type molten salt heater is connected to the molten salt inlet of the high-temperature molten salt storage tank.

[0014] Preferably, the waste heat boiler unit further includes a waste heat boiler, a low-pressure steam drum, a low-pressure superheater, a high-pressure steam drum, a high-pressure superheater and a second feed water pump. The high-pressure superheater, the high-pressure steam drum, the low-pressure superheater, the low-pressure steam drum and the feed water heater are arranged in the waste heat boiler in sequence along the flue gas inlet to flue gas outlet flow direction. The feed water outlet of the feed water heater is respectively connected to the feed water inlets of the low-pressure steam drum and the high-pressure steam drum. The second feed water pump is installed at the feed water inlet of the high-pressure steam drum. The steam outlet of the high-pressure steam drum is connected to the steam inlet of the high-pressure superheater. The steam outlet of the high-pressure superheater is connected to the steam turbine unit to do work and generate electricity. The steam outlet of the low-pressure steam drum is connected to the steam inlet of the low-pressure superheater. The steam outlet of the low-pressure superheater is connected to the steam turbine unit to do work and generate electricity.

[0015] Preferably, the high-pressure steam drum is located on the side of the high-pressure superheater away from the flue gas inlet. The secondary molten salt heater is arranged between the high-pressure steam drum and the high-pressure superheater, or the secondary molten salt heater is arranged on the side of the high-pressure superheater close to the flue gas inlet.

[0016] Preferably, the steam turbine unit includes a medium-high pressure cylinder, a low-pressure cylinder, a second generator and a connecting pipe. The steam outlet of the high-pressure steam superheater is connected to the steam inlet of the medium-high pressure cylinder. The steam outlet of the low-pressure steam superheater is connected to the steam inlet of the low-pressure cylinder. The steam outlet of the waste heat boiler unit is respectively connected to the steam inlets of the medium-high pressure cylinder and the low-pressure cylinder. The steam outlet of the medium-high pressure cylinder is connected to the steam inlet of the low-pressure cylinder through the connecting pipe. The medium-high pressure cylinder and the low-pressure cylinder are both coaxially connected to the second generator. The medium-high pressure cylinder and the low-pressure cylinder do work simultaneously to drive the second generator to generate electricity.

[0017] Preferably, the circulating power generation mechanism further includes a gas turbine unit. The gas turbine unit includes a gas turbine compressor, a gas turbine combustor, a gas turbine turbine and a first generator. The exhaust port of the gas turbine compressor is connected to the intake port of the gas turbine combustor. The exhaust port of the gas turbine combustor is connected to the intake port of the gas turbine turbine. The exhaust port of the gas turbine turbine is connected to the intake port of the waste heat boiler. The exhaust port of the gas turbine turbine drives the first generator to generate electricity.

[0018] The present invention also provides a method for the combined cycle coupled molten salt energy storage deep peak shaving system as described above, including the following steps:

[0019] Determine whether the system participates in power peak shaving;

[0020] If the system participates in power peak shaving, determine whether to reduce or increase the output electrical load;

[0021] If it is necessary to reduce the output electrical load, part of the flue gas waste heat is used to heat the waste heat boiler unit to generate steam. The steam of the waste heat boiler unit drives the steam turbine unit to do work and generate electricity, and the other part of the flue gas waste heat is used to heat the molten salt energy storage mechanism and store heat;

[0022] If it is necessary to increase the output electrical load, all the flue gas waste heat is used to heat the waste heat boiler unit to generate steam. The steam of the waste heat boiler unit drives the steam turbine unit to do work and generate electricity; if it is necessary to further increase the output electrical load, it is also necessary to supplement the water supply to the molten salt energy storage mechanism through the feed water heater. The molten salt energy storage mechanism releases heat to heat the feed water supplemented by the feed water heater into steam, and the steam of the molten salt energy storage mechanism is also used to drive the steam turbine unit to do work and generate electricity.

[0023] Preferably,

[0024] If it is necessary to reduce the output electrical load, the other part of the flue gas waste heat is used to heat the molten salt energy storage mechanism and store heat. The specific steps are as follows: The low-temperature molten salt in the low-temperature molten salt storage tank is driven by the low-temperature molten salt pump and sequentially enters the primary molten salt heater and the secondary molten salt heater to be heated in a cascade manner to obtain high-temperature molten salt, and then the high-temperature molten salt is sent to the high-temperature molten salt storage tank for storage;

[0025] If it is necessary to further increase the output electrical load, the specific steps are as follows: The high-temperature molten salt output from the high-temperature molten salt storage tank is sequentially passed through the high-pressure steam superheater, the high-pressure steam generator, the low-pressure steam superheater and the low-pressure steam generator for cascade cooling to obtain low-temperature molten salt and store it in the low-temperature molten salt storage tank. At the same time, the feed water in the feed water heater enters the low-pressure steam generator and the high-pressure steam generator respectively, and the feed water is pressurized by the first feed water pump before entering the high-pressure steam generator. The high-pressure steam generated by the high-pressure steam generator enters the high-pressure steam superheater for further heating, and then the steam enters the steam turbine unit to do work and generate electricity. The low-pressure steam generated by the low-pressure steam generator enters the low-pressure steam superheater for further heating, and then the steam enters the steam turbine unit to do work and generate electricity.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] In the above technical solution, a combined cycle coupled molten salt energy storage deep peak shaving system is provided. The low-temperature molten salt in the low-temperature molten salt storage tank is stepwise heated by passing through a primary molten salt heater and a secondary molten salt heater, and then stored in the high-temperature molten salt storage tank, that is, the waste heat of the high-temperature flue gas is stored, realizing the stepwise and efficient utilization of the waste heat of the high-temperature flue gas and greatly reducing the heat transfer temperature difference. Secondly, the high-temperature molten salt output from the warm molten salt storage tank is stepwise cooled by passing through a high-pressure steam superheater, a high-pressure steam generator, a low-pressure steam superheater, and a low-pressure steam generator in sequence, and then the low-temperature molten salt is obtained and stored in the low-temperature molten salt storage tank, that is, the heat stored in the high-temperature molten salt storage tank is released. By reasonably designing the distribution positions of various heat exchangers using the heat of the high-temperature molten salt, different-parameter steam based on the stepwise matching of energy grades is efficiently produced, realizing the stepwise and efficient utilization of the heat of the high-temperature molten salt, greatly reducing the heat transfer temperature difference, and reducing irreversible losses. In addition, the water outlet of the feed water heater is respectively connected to the water inlets of the high-pressure steam generator and the low-pressure steam generator. By supplementing the feed water flow required for steam production when the molten salt energy storage mechanism releases heat through the feed water heater, the output of high-quality steam is increased. After the steam is output, it continues to act on the steam turbine unit, and the power generation capacity of the steam turbine unit is also greatly improved. Brief Description of the Drawings

[0028] Figure 1 It is a schematic diagram of a combined cycle coupled molten salt energy storage deep peak shaving system in one embodiment of the present invention;

[0029] Figure 2 It is a schematic diagram of a combined cycle coupled molten salt energy storage deep peak shaving system in another embodiment of the present invention;

[0030] Figure 3 is Figure 1 a schematic diagram after installing an electric heating type molten salt heater as shown.

[0031] Description of the Reference Numerals:

[0032] 10. Waste heat boiler unit; 101. Feed water heater; 102. Waste heat boiler; 103. Low-pressure steam drum; 104. Low-pressure superheater; 105. High-pressure steam drum; 106. High-pressure superheater; 107. Second feed water pump; 20. Steam turbine unit; 201. Medium-high pressure cylinder; 202. Low-pressure cylinder; 203. Second generator; 204. Connecting pipe; 30. Molten salt energy storage mechanism; 301. Low-temperature molten salt storage tank; 302. High-temperature molten salt storage tank; 303. Primary molten salt heater; 304. Secondary molten salt heater; 305. Low-temperature molten salt pump; 306. High-temperature molten salt pump; 307. High-pressure steam superheater; 308. High-pressure steam generator; 309. Low-pressure steam superheater; 310. Low-pressure steam generator; 311. First feed water pump; 312. Electric heating type molten salt heater; 40. Circulating feed water unit; 401. Condensate pump; 402. Deaerator; 403. Condensate storage tank; 404. Circulating water pump; 405. Condensate pipe; 406. Condenser; 50. Gas turbine unit; 501. Gas turbine compressor; 502. Gas turbine combustion chamber; 503. Gas turbine turbine; 504. First generator; 601. First valve; 602. Second valve; 603. Third valve; 604. Fourth valve; 605. Fifth valve; 606. Sixth valve; 607. Seventh valve; 608. Eighth valve; 609. Ninth valve; 610. Tenth valve; 611. Eleventh valve; 612. Twelfth valve; 613. Thirteenth valve; 614. Fourteenth valve; 615. Fifteenth valve; 616. Sixteenth valve; 617. Seventeenth valve. Detailed implementation manners

[0033] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0034] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0035] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the connection inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] In an embodiment of the present invention, a combined cycle coupled molten salt energy storage deep peak shaving system is provided. This system makes a cascade and efficient utilization of the waste heat of high-temperature flue gas and the heat of high-temperature molten salt, greatly reducing the heat transfer temperature difference and irreversible losses. It can also supplement the feed water flow required for steam production during the heat release of the molten salt energy storage mechanism 30, increasing the output of high-quality steam, and acting the steam on the steam turbine unit 20, greatly enhancing the power generation capacity of the steam turbine unit 20.

[0037] Please refer to Figures 1 - 3 , in one embodiment, the system at least includes a cycle power generation mechanism. The cycle power generation mechanism includes a gas turbine unit 50. The gas turbine unit 50 includes a gas turbine compressor 501, a gas turbine combustion chamber 502, a gas turbine turbine 503, and a first generator 504. The exhaust port of the gas turbine compressor 501 is connected to the intake port of the gas turbine combustion chamber 502. The exhaust port of the gas turbine combustion chamber 502 is connected to the intake port of the gas turbine turbine 503. The exhaust port of the gas turbine turbine 503 drives the first generator 504 to generate electricity. The exhaust port of the gas turbine turbine 503 is connected to the intake port of the waste heat boiler 102. The gas discharged from the gas turbine turbine 503 is flue gas, and the present invention utilizes the waste heat of this flue gas.

[0038] In order to utilize the waste heat of the flue gas, the cycle power generation mechanism further includes a steam turbine unit 20, a waste heat boiler unit 10, and a circulating feed water unit 40. The steam generated by the waste heat boiler unit 10 enters the steam turbine unit 20 to do work and generate electricity. The system further includes a molten salt energy storage mechanism 30.

[0039] The steam turbine unit 20 includes a medium-high pressure cylinder 201, a low-pressure cylinder 202, a second generator 203, and a connecting pipe 204. The steam outlet of the high-pressure steam superheater 307 is connected to the steam inlet of the medium-high pressure cylinder 201.

[0040] The steam outlet of the low-pressure steam superheater 309 is connected to the steam inlet of the low-pressure cylinder 202. The steam outlets of the waste heat boiler unit 10 are respectively connected to the steam inlets of the medium-high pressure cylinder 201 and the low-pressure cylinder 202. The steam outlet of the medium-high pressure cylinder 201 is connected to the steam inlet of the low-pressure cylinder 202 through the connecting pipe 204. The medium-high pressure cylinder 201 and the low-pressure cylinder 202 are both coaxially connected to the second generator 203. The medium-high pressure cylinder 201 and the low-pressure cylinder 202 perform work simultaneously to drive the second generator 203 to generate electricity.

[0041] The circulating feed water unit 40 includes a condensate pump 401, a deaerator 402, a condensate water storage tank 403, a circulating water pump 404, a condensate water pipe 405, and a condenser 406.

[0042] The waste heat boiler unit 10 includes a waste heat boiler 102, a feed water heater 101, a low-pressure steam drum 103, a low-pressure superheater 104, a high-pressure steam drum 105, a high-pressure superheater 106, and a second feed water pump 107. The high-pressure superheater 106, the high-pressure steam drum 105, the low-pressure superheater 104, the low-pressure steam drum 103, and the feed water heater 101 are arranged in sequence along the flow direction of the flue gas from the flue gas inlet to the flue gas outlet in the waste heat boiler 102.

[0043] Loop 1: In order to use the high-temperature flue gas from the gas turbine turbine 503 to heat the feed water to produce steam, and then the steam enters the steam turbine unit 20 to perform work and generate electricity. Specifically, open and adjust the first valve 601, the second valve 602, the fifth valve 605, the seventh valve 607, the eighth valve 608, the tenth valve 610, and the fifteenth valve 615. After the feed water is heated by the feed water heater 101, it is divided into two paths of feed water. The feed water outlets of the feed water heater 101 are respectively connected to the feed water inlets of the low-pressure steam drum 103 and the high-pressure steam drum 105.

[0044] One branch: A first valve 601 is installed at the water inlet of the low-pressure steam drum 103. The steam outlet of the low-pressure steam drum 103 is connected to the steam inlet of the low-pressure superheater 104. The low-pressure steam generated by the low-pressure steam drum 103 enters the low-pressure superheater 104 for further heating. A fifth valve 605 is installed at the steam outlet of the low-pressure superheater 104. The steam outlet of the low-pressure superheater 104 is connected to the steam inlet of the low-pressure cylinder 202. The steam of the low-pressure superheater 104 directly enters the low-pressure cylinder 202 of the steam turbine to do work. Another branch: A second feed water pump 107 and a second valve 602 are installed at the water inlet of the high-pressure steam drum 105. The feed water entering the high-pressure steam drum 105 is first pressurized by the first feed water pump. The steam outlet of the high-pressure steam drum 105 is connected to the steam inlet of the high-pressure superheater 106. The high-pressure steam generated by the high-pressure steam drum 105 enters the high-pressure superheater 106 for further heating. The steam outlet of the high-pressure superheater 106 is connected to the steam inlet of the intermediate and high-pressure cylinder 201. An eighth valve 608 is installed at the steam outlet of the high-pressure superheater 106. The steam in the high-pressure superheater 106 sequentially enters the intermediate and high-pressure cylinder 201 and the low-pressure cylinder 202 of the steam turbine to do work. A tenth valve 610 is installed at the steam inlet of the intermediate and high-pressure cylinder 201. The steam outlet of the intermediate and high-pressure cylinder 201 is connected to the steam inlet of the low-pressure cylinder 202 through a connecting pipe 204. A seventh valve 607 is installed on the connecting pipe 204. The intermediate and high-pressure cylinder 201 and the low-pressure cylinder 202 do work simultaneously to drive the second generator 203 to generate electricity.

[0045] The steam outlet of the low-pressure cylinder 202 is connected to the exhaust steam inlet of the condenser 406. The condensate water outlet of the condenser 406 is connected to the water inlet of the deaerator 402 through a condensate water pipe 405. A condensate water pump 401 and a fifteenth valve 615 are sequentially installed on the condensate water pipe 405 along the water flow direction. The water outlet of the deaerator 402 is connected to the water inlet of the feed water heater 101, thus forming Loop 1.

[0046] As a preferred embodiment, a condensate water storage tank 403 is used to meet the condensate water demand when the system participates in power peak shaving. The water outlet of the condensate water pump 401 is connected to the water inlet of the condensate water storage tank 403. A sixteenth valve 616 is installed at the water inlet of the condensate water storage tank 403. The water outlet of the condensate water storage tank 403 is connected to the water inlet of the deaerator 402. A circulating water pump 404 and a seventeenth valve 617 are installed at the water outlet of the condensate water storage tank 403. The water outlet of the deaerator 402 is connected to the water inlet of the feed water heater 101.

[0047] It can be understood that when the system participates in power peak shaving and needs to reduce the output electrical load, the 15th valve 615 and the 16th valve 616 are opened and adjusted, the 17th valve 617 is closed, the condensate water volume delivered to the deaerator 402 through the condensate pump 401 is reduced, and the excess condensate water from the condensate pump 401 is directly delivered to the condensate storage tank 403 for storage. Thus, the superheated steam flow rate delivered from the waste heat boiler 102 to the steam turbine unit 20 is reduced, the work capacity of the steam turbine unit 20 is decreased, and the electrical load output by the second generator 203 is reduced to meet the power peak shaving requirements.

[0048] When the system participates in power peak shaving and needs to increase the output electrical load, the 15th valve 615 and the 17th valve 617 are opened and adjusted, the 16th valve 616 is closed, and the condensate storage tank 403 supplements the insufficient condensate water volume of the system. When the system participates in power peak shaving and needs to further increase the output electrical load, it can also supplement the water volume required for steam production during the heat release of the molten salt energy storage mechanism 30.

[0049] Specific implementation manner of the molten salt energy storage mechanism 30: The molten salt energy storage mechanism 30 includes a low-temperature molten salt storage tank 301, a high-temperature molten salt storage tank 302, a primary molten salt heater 303, a secondary molten salt heater 304, a low-temperature molten salt pump 305, a high-temperature molten salt pump 306 of the prior art, a high-pressure steam superheater 307, a high-pressure steam generator 308, a low-pressure steam superheater 309, a low-pressure steam generator 310, and a first feed water pump 311.

[0050] Among them, as Figure 1 、 Figure 3 shown, the high-pressure steam drum 105 is located on the side of the high-pressure superheater 106 away from the flue gas inlet, and the secondary molten salt heater 304 is arranged between the high-pressure steam drum 105 and the high-pressure superheater 106, that is, the secondary molten salt heater 304 is arranged on the side of the high-pressure steam drum 105 close to the upstream of the flue gas. Both the primary molten salt heater 303 and the secondary molten salt heater 304 are arranged on the side of the low-pressure superheater 104 located at the flue gas inlet.

[0051] Loop 2: Energy storage or heat release by the molten salt energy storage mechanism 30.

[0052] When the system participates in power peak shaving and needs to reduce the output electrical load, in order to keep the steam turbine unit 20 running at a low load, a part of the flue gas waste heat from the gas turbine turbine 503 needs to be stored in the molten salt energy storage mechanism 30. Specifically, the 11th valve 611 and the 12th valve 612 are opened and adjusted.

[0053] A low-temperature molten salt pump 305 and an eleventh valve 611 are installed at the molten salt outlet of the low-temperature molten salt storage tank 301. The primary molten salt heater 303 is arranged between the high-pressure steam drum 105 and the low-pressure superheater 104 in the waste heat boiler 102. The molten salt outlet of the low-temperature molten salt storage tank 301 is connected to the molten salt inlet of the primary molten salt heater 303. The molten salt outlet of the primary molten salt heater 303 is connected to the molten salt inlet of the secondary molten salt heater 304. The molten salt outlet of the secondary molten salt heater 304 is connected to the molten salt inlet of the high-temperature molten salt storage tank 302. A twelfth valve 612 is installed at the molten salt inlet of the high-temperature molten salt storage tank 302.

[0054] It can be understood that the low-temperature molten salt in the low-temperature molten salt storage tank 301 is driven by the low-temperature molten salt pump 305 and sequentially enters the primary molten salt heater 303 and the secondary molten salt heater 304, where it is stepwise heated to obtain high-temperature molten salt. The high-temperature molten salt is sent to the high-temperature molten salt storage tank 302 for storage, that is, the waste heat of the high-temperature flue gas is stored, realizing the stepwise and efficient utilization of the waste heat of the high-temperature flue gas, greatly reducing the heat transfer temperature difference and reducing the irreversible loss. Using the molten salt energy storage mechanism 30 to store the waste heat of the high-temperature flue gas avoids preferentially reducing the operating load of the gas turbine unit 50 and largely ensures the high-efficiency operation of the circulating power generation mechanism.

[0055] When the system participates in power peak shaving and needs to further increase the output power load, the steam generated by the heat release of the molten salt energy storage mechanism 30 is transported to the steam turbine unit 20 to further increase the operating load of the steam turbine unit 20, thereby increasing the output power load of the system.

[0056] Specifically, a high-temperature molten salt pump 306 and a thirteenth valve 613 are installed at the molten salt outlet of the high-temperature molten salt storage tank 302 and are connected to the molten salt inlet of the high-pressure steam superheater 307. The molten salt outlet of the high-pressure steam superheater 307 is connected to the molten salt inlet of the high-pressure steam generator 308. The molten salt outlet of the high-pressure steam generator 308 is connected to the molten salt inlet of the low-pressure steam superheater 309. The molten salt outlet of the low-pressure steam superheater 309 is connected to the molten salt inlet of the low-pressure steam generator 310. The molten salt outlet of the low-pressure steam generator 310 is connected to the molten salt inlet of the low-temperature molten salt storage tank 301. A fourteenth valve 614 is installed at the molten salt inlet of the low-temperature molten salt storage tank 301.

[0057] It can be understood that the high-temperature molten salt output from the high-temperature molten salt storage tank 302 undergoes cascaded cooling in sequence through the high-pressure steam superheater 307, the high-pressure steam generator 308, the low-pressure steam superheater 309, and the low-pressure steam generator 310, and then the low-temperature molten salt is obtained and stored in the low-temperature molten salt storage tank 301. That is, the heat stored in the high-temperature molten salt storage tank 302 is released. From the high-temperature molten salt storage tank 302 to the low-temperature molten salt storage tank 301, based on the principle of cascaded utilization of energy, the distribution positions of various heat exchangers using the heat of high-temperature molten salt are reasonably designed to efficiently produce different-parameter steam based on the cascaded matching of energy grades, release the heat stored in the high-temperature molten salt storage tank 302, not only realize the cascaded and efficient utilization of high-temperature molten salt heat, greatly reduce the heat transfer temperature difference, and further reduce the irreversible loss, but also increase the output of high-quality steam and greatly improve the work capacity of the steam turbine. The heat released from the high-temperature molten salt storage tank 302 is used together with the heat output from the feedwater heater 101 in loop three. After the steam is output, it acts on the steam turbine unit 20 for power generation to further increase the operating load of the steam turbine unit 20, thereby increasing the output electric load of the system.

[0058] Loop three: When the system participates in power peak shaving and needs to continue to increase the output electric load, the steam generated by the heat release of the molten salt energy storage mechanism 30 is transported to the steam turbine unit 20 to further increase the operating load of the steam turbine unit 20, thereby increasing the output electric load of the system. Specifically, open and adjust the third valve 603, the fourth valve 604, the ninth valve 609, the thirteenth valve 613, and the fourteenth valve 614, and close the eleventh valve 611 and the twelfth valve 612. The feedwater is divided into two paths after being heated by the feedwater heater 101. The feedwater outlets of the feedwater heater 101 are respectively connected to the feedwater inlets of the high-pressure steam generator 308 and the low-pressure steam generator 310.

[0059] One branch: A fourth valve 604 and a first feed water pump 311 are installed at the feed water inlet of the high-pressure steam generator 308. The feed water entering the high-pressure steam generator 308 is first pressurized by the first feed water pump 311. The steam outlet of the high-pressure steam generator 308 is connected to the steam inlet of the high-pressure steam superheater 307. The high-pressure steam generated by the high-pressure steam generator 308 then enters the high-pressure steam superheater 307 for further heating. The steam outlet of the high-pressure steam superheater 307 is connected to the steam inlet of the intermediate and high-pressure cylinder 201 of the steam turbine, and a ninth valve 609 is installed at the steam outlet of the high-pressure steam superheater 307. The steam in the high-pressure steam superheater 307 sequentially enters the intermediate and high-pressure cylinder 201 and the low-pressure cylinder 202 of the steam turbine to perform work. Another branch: A third valve 603 is installed at the feed water inlet of the low-pressure steam generator 310. The steam outlet of the low-pressure steam generator 310 is connected to the steam inlet of the low-pressure steam superheater 309. The low-pressure steam generated by the low-pressure steam generator 310 then enters the low-pressure steam superheater 309 for further heating. A sixth valve 606 is installed at the steam outlet of the low-pressure steam superheater 309. The steam outlet of the low-pressure steam superheater 309 is connected to the steam inlet of the low-pressure cylinder 202 of the steam turbine, and the steam from the low-pressure steam superheater 309 directly enters the low-pressure cylinder 202 of the steam turbine to perform work. The intermediate and high-pressure cylinder 201 and the low-pressure cylinder 202 of the steam turbine perform work simultaneously to drive the second generator 203 to generate electricity.

[0060] It can be understood that in loop three, the feed water heater 101 is connected to the high-pressure steam generator 308 and the low-pressure steam generator 310 to supplement the feed water flow required for generating steam during the heat release of the molten salt energy storage mechanism 30, increasing the output of high-quality steam. At the same time, when the system participates in power peak shaving and needs to continue to increase the output electrical load, loop three and loop one jointly perform work on the steam turbine unit 20. After the steam outputs of the two loops, they both act on the steam turbine unit 20, greatly improving the ability of the steam turbine unit 20 to perform work and generate electricity.

[0061] In addition, as Figure 3 shown, the molten salt energy storage mechanism 30 further includes an electric heating type molten salt heater 312. The electric heating type molten salt heater 312 is installed at the molten salt outlet of the secondary molten salt heater 304. The molten salt outlet of the electric heating type molten salt heater 312 is connected to the molten salt inlet of the high-temperature molten salt storage tank 302.

[0062] It can be understood that when both the steam turbine unit 20 and the gas turbine unit 50 need to operate at low loads, the high-temperature flue gas from the gas turbine turbine 503 is first used to heat the feed water in the waste heat boiler unit 10 to generate steam, and the steam is used to drive the steam turbine unit 20 to generate electricity. Then, it is used to heat the molten salt for heat storage. At this time, the insufficient waste heat of the high-temperature flue gas causes the low-temperature molten salt to not be heated to the set temperature by the high-temperature flue gas. Therefore, the low-temperature molten salt in the low-temperature molten salt storage tank 301 sequentially enters the primary molten salt heater 303 and the secondary molten salt heater 304 to be heated in a cascade manner, and then enters the electric heating type molten salt heater 312 to further heat the molten salt to the set temperature by using electric energy, and then returns to the high-temperature molten salt storage tank 302 for storage. Therefore, by using the electric heating type molten salt heater 312 to supplementally heat the molten salt with electric energy, it not only makes up for the insufficient waste heat of the high-temperature flue gas and ensures the molten salt temperature required for heat storage of the molten salt energy storage mechanism 30, but also consumes a part of the output electric load through the electric heating type molten salt heater 312 to meet the load reduction requirement of power peak shaving, so that the operating load of the gas turbine unit 50 during power peak shaving is relatively reduced less, and further effectively ensures the high-efficiency operation of the combined cycle power generation mechanism.

[0063] Please refer to Figure 2 , in another embodiment, the main difference from the previous embodiment is that in this embodiment, the secondary molten salt heater 304 is arranged on the side close to the flue gas inlet of the high-pressure superheater 106. Both the primary molten salt heater 303 and the secondary molten salt heater 304 are arranged on the side of the low-pressure superheater 104 located at the flue gas inlet, and have similar technical effects to the previous embodiment.

[0064] Please continue to refer to Figures 1 - 3 , the present invention embodiment also provides a regulation method for a combined cycle coupled molten salt energy storage deep peak shaving system, including the following steps:

[0065] Judge whether the system participates in power peak shaving.

[0066] When the system does not participate in power peak shaving, both the gas turbine unit 50 and the steam turbine unit 20 operate at high loads to ensure the high-efficiency operation of the circulating power generation mechanism. The high-temperature flue gas from the gas turbine turbine 503 is all used to heat the feed water to produce steam, which then enters the steam turbine unit 20 to do work and generate electricity. At this time, open and adjust the first valve 601, the second valve 602, the fifth valve 605, the seventh valve 607, the eighth valve 608, the tenth valve 610 and the fifteenth valve 615. The feed water from the deaerator 402 is heated by the feed water heater 101 and then divided into two paths of feed water, which respectively enter the low-pressure steam drum 103 and the high-pressure steam drum 105. And the feed water entering the high-pressure steam drum 105 is first pressurized by the first feed water pump. The high-pressure steam generated by the high-pressure steam drum 105 enters the high-pressure superheater 106 for further heating, and then successively enters the medium-high pressure cylinder 201 and the low-pressure cylinder 202 to do work; the low-pressure steam generated by the low-pressure steam drum 103 enters the low-pressure superheater 104 for further heating, and then directly enters the low-pressure cylinder 202 to do work. The medium-high pressure cylinder 201 and the low-pressure cylinder 202 do work simultaneously to drive the second generator 203 to generate electricity. The exhaust steam generated after the steam turbine unit 20 does work enters the condenser 406 to form condensate, and then returns to the deaerator 402 through the condensate pump 401.

[0067] If the system participates in power peak shaving, it is judged whether to reduce or increase the output electric load.

[0068] When it is necessary to reduce the output electric load, the gas turbine unit 50 needs to operate at a high load, and the steam turbine unit 20 operates at a low load. Part of the high-temperature flue gas from the gas turbine turbine 503 is used to heat the waste heat boiler unit 10 to produce steam. The steam of the waste heat boiler unit 10 drives the steam turbine unit 20 to do work and generate electricity, and the other part of the flue gas waste heat is used to heat the molten salt energy storage mechanism 30 and store heat. It can be understood that it is preferred to reduce the operating load of the steam turbine unit 20 and still keep the gas turbine unit 50 operating at a high load. At this time, the molten salt energy storage mechanism 30 is used to store the excess high-temperature flue gas waste heat, thus ensuring the high-efficiency operation of the circulating power generation mechanism and avoiding the direct emission loss of the flue gas waste heat.

[0069] Specifically, open and adjust the 15th valve 615 and the 16th valve 616, close the 17th valve 617, reduce the amount of condensate water transported to the deaerator 402 by the condensate pump 401, and directly transport the excess condensate water from the condensate pump 401 to the condensate water storage tank 403 for storage. Open and adjust the 1st valve 601, the 2nd valve 602, the 5th valve 605, the 7th valve 607, the 8th valve 608, and the 10th valve 610, and correspondingly reduce the feed water flow rate from the deaerator 402 to the waste heat boiler 102. Thereby, reduce the superheated steam flow rate from the waste heat boiler 102 to the steam turbine unit 20, reduce the work capacity of the steam turbine unit 20, and thus reduce the electrical load output by the second generator 203 to meet the power peak shaving demand.

[0070] Meanwhile, open and adjust the 11th valve 611 and the 12th valve 612. The low-temperature molten salt in the low-temperature molten salt storage tank 301 is driven by the low-temperature molten salt pump 305 and sequentially enters the primary molten salt heater 303 and the secondary molten salt heater 304 to be stepwise heated into high-temperature molten salt, and then returns to the high-temperature molten salt storage tank 302 for storage. Thereby, the waste heat of the high-temperature flue gas is stored through the molten salt energy storage system. The cascade high-efficiency utilization of the waste heat of the high-temperature flue gas is realized, the heat transfer temperature difference is greatly reduced, and the irreversible loss is reduced. The molten salt energy storage mechanism 30 is used to store the waste heat of the high-temperature flue gas, avoiding the preferential selection of reducing the operating load of the gas turbine unit 50, and largely ensuring the high-efficiency operation of the combined cycle power generation mechanism.

[0071] As Figure 3 shown, when the system participates in power peak shaving and needs to further reduce the output electrical load, both the steam turbine unit 20 and the gas turbine unit 50 need to operate at low loads. It can be understood that when choosing to simultaneously reduce the operating loads of the gas turbine unit 50 and the steam turbine unit 20, at this time, the molten salt energy storage mechanism 30 is used to store the excess waste heat of the high-temperature flue gas by heat storage, so as to further reduce the operating load of the steam turbine unit 20, and a part of the electrical load is consumed by the electric heating type molten salt heater 312 to heat the molten salt, and is stored through the molten salt energy storage system. Thereby, the operating load of the gas turbine unit 50 is prevented from being too low, thus ensuring the operating efficiency of the combined cycle power generation system.

[0072] Specifically, the high-temperature flue gas from the gas turbine turbine 503 is first used to heat the feed water to generate steam to drive the steam turbine unit 20 to generate electricity. The feed water from the deaerator 402 is heated by the feed water heater 101 and then divided into two paths of feed water, which respectively enter the low-pressure steam drum 103 and the high-pressure steam drum 105, and finally act on the medium-high pressure cylinder 201 and the low-pressure cylinder 202, so that the medium-high pressure cylinder 201 and the low-pressure cylinder 202 simultaneously do work to drive the second generator 203 to generate electricity. The specific circulation loop will not be elaborated here, and reference can be made to the above system when it does not participate in power peak shaving.

[0073] The high-temperature flue gas from the gas turbine turbine 503 is reused to heat molten salt for heat storage. When the gas turbine unit 50 operates at low load, both the flue gas flow rate and temperature will decrease. Therefore, the waste heat of the high-temperature flue gas is insufficient, and the molten salt cannot be heated to the set temperature by the high-temperature flue gas. Then, the low-temperature molten salt in the low-temperature molten salt storage tank 301 sequentially enters the primary molten salt heater 303 and the secondary molten salt heater 304 for cascade heating, and then enters the electric heating type molten salt heater 312 to further heat the molten salt to the set temperature by using electric energy, and then returns to the high-temperature molten salt storage tank 302 for storage.

[0074] If it is necessary to increase the output electric load, both the gas turbine unit 50 and the steam turbine unit 20 need to operate at high load to ensure the high-efficiency operation of the circulating power generation mechanism. The waste heat of the high-temperature flue gas from the gas turbine turbine 503 is all used to heat the feed water in the waste heat boiler unit 10 to generate steam. Then, the steam of the waste heat boiler unit 10 drives the steam turbine unit 20 to do work and generate electricity.

[0075] Specifically, open and adjust the first valve 601, the second valve 602, the fifth valve 605, the seventh valve 607, the eighth valve 608, the tenth valve 610, and the fifteenth valve 615. The feed water from the deaerator 402 is heated by the feed water heater 101 and then divided into two paths of feed water, which respectively enter the low-pressure steam drum 103 and the high-pressure steam drum 105. And the feed water entering the high-pressure steam drum 105 is first pressurized by the first feed water pump. The high-pressure steam generated by the high-pressure steam drum 105 enters the high-pressure superheater 106 for further heating, and then sequentially enters the medium-high pressure cylinder 201 and the low-pressure cylinder 202 to do work. The low-pressure steam generated by the low-pressure steam drum 103 enters the low-pressure superheater 104 for further heating, and then directly enters the low-pressure cylinder 202 to do work. The medium-high pressure cylinder 201 and the low-pressure cylinder 202 do work simultaneously to drive the second generator 203 to generate electricity. The exhaust steam generated after the steam turbine unit 20 does work enters the condenser 406 to form condensate, and then returns to the deaerator 402 through the condensate pump 401. At the same time, open and adjust the seventeenth valve 617 and close the sixteenth valve 616, and use the condensate storage tank 403 to supplement the insufficient condensate flow rate of the combined cycle power generation system.

[0076] If it is necessary to continue to increase the output electric load, not only the gas turbine unit 50 and the steam turbine unit 20 need to operate at high load, but also the feed water supplemented by the feed water heater 101 needs to be heated to steam by the heat release of the molten salt energy storage mechanism 30. The generated steam is used to drive the steam turbine unit 20 to do work and generate electricity to further increase the operating load of the steam turbine unit 20 and further increase the output electric load. The feed water is heated by the feed water heater 101 and then divided into two paths of feed water, which continue to enter the low-pressure steam drum 103 and the high-pressure steam drum 105 respectively, and finally do work and generate electricity in the steam turbine unit 20. The specific steps will not be elaborated here.

[0077] In addition, the following steps need to be combined: Open and adjust the third valve 603, the fourth valve 604, the ninth valve 609, the thirteenth valve 613 and the fourteenth valve 614, and close the eleventh valve 611 and the twelfth valve 612. The feed water from the deaerator 402 is heated by the feed water heater 101 and then divided into two paths of feed water, which respectively enter the low-pressure steam generator 310 and the high-pressure steam generator 308. The feed water entering the high-pressure steam generator 308 is first pressurized by the first feed water pump 311. The high-pressure steam generated by the high-pressure steam generator 308 then enters the high-pressure steam superheater 307 for further heating, and then sequentially enters the intermediate and high-pressure cylinders 201 and the low-pressure cylinder 202 of the steam turbine to do work; the low-pressure steam generated by the low-pressure steam generator 310 enters the low-pressure steam superheater 309 for further heating, and then directly enters the low-pressure cylinder 202 of the steam turbine to do work. The intermediate and high-pressure cylinders 201 and the low-pressure cylinder 202 of the steam turbine do work simultaneously to drive the second generator 203 to generate electricity. The exhaust steam generated after the steam turbine unit 20 does work enters the condenser 406 to form condensate. Open and adjust the seventeenth valve 617 and close the sixteenth valve 616. The condensate storage tank 403 is also used to supplement the feed water flow required for generating steam when the molten salt energy storage system releases heat. The feed water heater 101 is connected to the high-pressure steam generator 308 and the low-pressure steam generator 310 to supplement the feed water flow required for generating steam when the molten salt energy storage mechanism 30 releases heat, increasing the output of high-quality steam.

[0078] Moreover, the high-temperature molten salt output from the high-temperature molten salt storage tank 302 sequentially passes through the high-pressure steam superheater 307, the high-pressure steam generator 308, the low-pressure steam superheater 309 and the low-pressure steam generator 310 for cascade cooling, and then the low-temperature molten salt is obtained and stored in the low-temperature molten salt storage tank 301.

[0079] It can be understood that from the high-temperature molten salt storage tank 302 to the low-temperature molten salt storage tank 301, based on the principle of cascade utilization of energy, the distribution positions of various heat exchangers using the heat of high-temperature molten salt are reasonably designed to efficiently produce different-parameter steam based on the cascade matching of energy grades, release the heat stored in the high-temperature molten salt storage tank 302, not only realizing the cascade efficient utilization of high-temperature molten salt heat, greatly reducing the heat transfer temperature difference and reducing irreversible losses, but also increasing the output of high-quality steam and greatly enhancing the work capacity of the steam turbine. The heat released from the high-temperature molten salt storage tank 302 is used together with the heat output from the feed water heater 101 to the low-pressure steam generator 310 and the high-pressure steam generator 308. After the steam is output, it acts on the steam turbine unit 20 to generate electricity to further increase the operating load of the steam turbine unit 20, thereby realizing an increase in the output electric load.

[0080] The above embodiments are only the preferred embodiments of the present invention, and cannot be used to limit the scope of protection of the present invention. Any non-substantive changes and substitutions made by those skilled in the art based on the present invention fall within the scope of protection required by the present invention.

Claims

1. A combined cycle coupled molten salt energy storage deep peak shaving system, characterized in that, Including: A cyclic power generation mechanism, including a steam turbine unit (20), a waste heat boiler unit (10) and a gas turbine unit (50). The steam generated by the waste heat boiler unit (10) enters the steam turbine unit (20) to do work and generate electricity. The exhaust port of the gas turbine unit (50) is connected to the intake port of the waste heat boiler unit (10). The waste heat boiler unit (10) includes a feed water heater (101); A molten salt energy storage mechanism (30), including a low-temperature molten salt storage tank (301), a high-temperature molten salt storage tank (302), a primary molten salt heater (303), a secondary molten salt heater (304), a low-temperature molten salt pump (305), a high-temperature molten salt pump (306), a high-pressure steam superheater (307), a high-pressure steam generator (308), a low-pressure steam superheater (309), a low-pressure steam generator (310) and a first feed water pump (311); Wherein, the molten salt outlet of the low-temperature molten salt storage tank (301) is installed with the low-temperature molten salt pump (305). The molten salt outlet of the low-temperature molten salt storage tank (301) is connected to the molten salt inlet of the primary molten salt heater (303). The molten salt outlet of the primary molten salt heater (303) is connected to the molten salt inlet of the secondary molten salt heater (304). The molten salt outlet of the secondary molten salt heater (304) is connected to the molten salt inlet of the high-temperature molten salt storage tank (302). The molten salt outlet of the high-temperature molten salt storage tank (302) is installed with the high-temperature molten salt pump (306) and is connected to the molten salt inlet of the high-pressure steam superheater (307). The molten salt outlet of the high-pressure steam superheater (307) is connected to the molten salt inlet of the high-pressure steam generator (308). The molten salt outlet of the high-pressure steam generator (308) is connected to the molten salt inlet of the low-pressure steam superheater (309). The molten salt outlet of the low-pressure steam superheater (309) is connected to the molten salt inlet of the low-pressure steam generator (310). The molten salt outlet of the low-pressure steam generator (310) is connected to the molten salt inlet of the low-temperature molten salt storage tank (301); The feed water outlet of the feed water heater (101) is respectively connected to the feed water inlets of the high-pressure steam generator (308) and the low-pressure steam generator (310). The feed water inlet of the high-pressure steam generator (308) is installed with the first feed water pump (311). The steam outlet of the high-pressure steam generator (308) is connected to the steam inlet of the high-pressure steam superheater (307). The steam outlet of the high-pressure steam superheater (307) is connected to the steam turbine unit (20) to do work and generate electricity. The steam outlet of the low-pressure steam generator (310) is connected to the steam inlet of the low-pressure steam superheater (309). The steam outlet of the low-pressure steam superheater (309) is connected to the steam turbine unit (20) to do work and generate electricity; The circulating power generation mechanism further includes a circulating feed water unit (40), and the circulating feed water unit (40) includes a condensate pump (401), a deaerator (402), a condensate storage tank (403), and a circulating water pump (404). The water outlet of the condensate pump (401) is connected to the water inlet of the condensate storage tank (403), the water outlet of the condensate storage tank (403) is connected to the water inlet of the deaerator (402), the circulating water pump (404) is installed at the water outlet of the condensate storage tank (403), and the water outlet of the deaerator (402) is connected to the feed water inlet of the feed water heater (101); The circulating feed water unit (40) further includes a condensate pipe (405) and a condenser (406). The water outlet of the condenser (406) is connected to the water inlet of the deaerator (402) through the condensate pipe (405), and the condensate pump (401) is installed on the condensate pipe (405); The molten salt energy storage mechanism (30) further includes an electric heating molten salt heater (312). The electric heating molten salt heater (312) is installed at the molten salt outlet of the secondary molten salt heater (304), and the molten salt outlet of the electric heating molten salt heater (312) is connected to the molten salt inlet of the high-temperature molten salt storage tank (302); When participating in power peak shaving and needing to reduce the output electric load, the gas turbine unit (50) needs to maintain high-load operation, and the steam turbine unit (20) maintains low-load operation. Part of the high-temperature flue gas from the gas turbine unit (50) is used to heat the waste heat boiler unit (10) to generate steam. The steam of the waste heat boiler unit (10) drives the steam turbine unit (20) to do work and generate electricity. Another part of the flue gas waste heat is used to heat the molten salt energy storage mechanism (30) for heat storage. At the same time, the amount of condensate water transported to the deaerator (402) by the condensate pump (401) is reduced, and the excess condensate water from the condensate pump (401) is directly transported to the condensate storage tank (403) for storage; When participating in power peak shaving and needing to further reduce the output electric load, the gas turbine unit (50) is kept running at low load. At the same time, a part of the electric load is consumed by the electric heating molten salt heater (312) to heat the molten salt, and the molten salt is stored through the molten salt energy storage system; When participating in power peak shaving and needing to increase the output electric load, both the gas turbine unit (50) and the steam turbine unit (20) need to maintain high-load operation. Then all the flue gas waste heat is used to heat the feed water in the waste heat boiler unit (10) to generate steam. The steam of the waste heat boiler unit (10) drives the steam turbine unit (20) to do work and generate electricity. At the same time, the condensate storage tank (403) is used to supplement the insufficient condensate water flow of the combined cycle power generation system; When it is necessary to continuously increase the output electrical load to participate in power peak shaving, the gas turbine unit (50) and the steam turbine unit (20) are kept running at high load. It is also necessary to heat the feed water supplemented by the feed water heater (101) into steam by the heat release of the molten salt energy storage mechanism (30), and the generated steam is used to drive the steam turbine unit (20) to do work and generate electricity. The specific steps are as follows: The high-temperature molten salt output from the high-temperature molten salt storage tank (302) sequentially passes through the high-pressure steam superheater (307), the high-pressure steam generator (308), the low-pressure steam superheater (309) and the low-pressure steam generator (310) for cascade cooling, and then the low-temperature molten salt is stored in the low-temperature molten salt storage tank (301). At the same time, the feed water in the feed water heater (101) enters the low-pressure steam generator (310) and the high-pressure steam generator (308) respectively, and the feed water is pressurized by the first feed water pump (311) before entering the high-pressure steam generator (308). The high-pressure steam generated by the high-pressure steam generator (308) enters the high-pressure steam superheater (307) for further heating, and then the steam enters the steam turbine unit (20) to do work and generate electricity. The low-pressure steam generated by the low-pressure steam generator (310) enters the low-pressure steam superheater (309) for further heating, and then the steam enters the steam turbine unit (20) to do work and generate electricity.

2. The combined cycle coupled molten salt energy storage deep peak shaving system according to claim 1, wherein The waste heat boiler unit (10) further includes a waste heat boiler (102), a low-pressure steam drum (103), a low-pressure superheater (104), a high-pressure steam drum (105), a high-pressure superheater (106) and a second feed water pump (107). The high-pressure superheater (106), the high-pressure steam drum (105), the low-pressure superheater (104), the low-pressure steam drum (103) and the feed water heater (101) are sequentially arranged in the waste heat boiler (102) along the flow direction from the flue gas inlet to the flue gas outlet. The feed water outlet of the feed water heater (101) is respectively connected to the feed water inlets of the low-pressure steam drum (103) and the high-pressure steam drum (105). The second feed water pump (107) is installed at the feed water inlet of the high-pressure steam drum (105). The steam outlet of the high-pressure steam drum (105) is connected to the steam inlet of the high-pressure superheater (106). The steam outlet of the high-pressure superheater (106) is connected to the steam turbine unit (20) to do work and generate electricity. The steam outlet of the low-pressure steam drum (103) is connected to the steam inlet of the low-pressure superheater (104). The steam outlet of the low-pressure superheater (104) is connected to the steam turbine unit (20) to do work and generate electricity.

3. The combined cycle coupled molten salt energy storage deep peak shaving system according to claim 2, wherein, The secondary molten salt heater (304) is arranged between the high-pressure steam drum (105) and the high-pressure superheater (106), or the secondary molten salt heater (304) is arranged on the side of the high-pressure superheater (106) close to the flue gas inlet.

4. The combined cycle coupled molten salt energy storage deep peak shaving system according to claim 1, wherein, The steam turbine unit (20) includes a medium and high pressure cylinder (201), a low pressure cylinder (202), a second generator (203), and a connecting pipe (204). The steam outlet of the high pressure steam superheater (307) is connected to the steam inlet of the medium and high pressure cylinder (201). The steam outlet of the low pressure steam superheater (309) is connected to the steam inlet of the low pressure cylinder (202). The steam outlet of the waste heat boiler unit (10) is respectively connected to the steam inlets of the medium and high pressure cylinder (201) and the low pressure cylinder (202). The steam outlet of the medium and high pressure cylinder (201) is connected to the steam inlet of the low pressure cylinder (202) through the connecting pipe (204). The medium and high pressure cylinder (201) and the low pressure cylinder (202) are both coaxially connected to the second generator (203). The medium and high pressure cylinder (201) and the low pressure cylinder (202) perform work simultaneously to drive the second generator (203) to generate electricity.

5. The combined cycle coupled molten salt energy storage deep peak shaving system according to claim 1, characterized in that The cycle power generation mechanism further includes a gas turbine unit (50). The gas turbine unit (50) includes a gas turbine compressor (501), a gas turbine combustion chamber (502), a gas turbine turbine (503), and a first generator (504). The exhaust port of the gas turbine compressor (501) is connected to the intake port of the gas turbine combustion chamber (502). The exhaust port of the gas turbine combustion chamber (502) is connected to the intake port of the gas turbine turbine (503). The exhaust port of the gas turbine turbine (503) is connected to the intake port of the waste heat boiler (102). The gas turbine turbine (503) drives the first generator (504) to generate electricity.

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