A thermal power unit coupled with molten salt energy storage deep peak regulation system and method thereof

Abstract

The present invention relates to a thermal power unit coupled with molten salt energy storage deep peak regulation system and method thereof, wherein the system comprises: a circulating power generation mechanism, comprising a steam turbine unit and a waste heat utilization device, wherein the steam generated by the waste heat utilization device enters the steam turbine unit to perform work and generate electricity, and the waste heat utilization device comprises a feed water heater; a molten salt energy storage mechanism, comprising an energy storage component, an electrically heated molten salt heater, a molten salt bypass pipe, an electrically heated steam superheater, a steam bypass pipe, a high-temperature molten salt storage tank, 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 enables the flue gas waste heat to heat the molten salt in multiple stages for energy storage, and at the same time enables the high-temperature molten salt heat to heat the feed water in multiple stages to produce steam of different qualities, thereby realizing the step-by-step efficient utilization of the high-temperature flue gas waste heat and the high-temperature molten salt heat, reducing irreversible losses, and in addition, with the aid of electric heating, increasing the output of high-quality steam.

Description

Technical Field

[0001] The present invention relates to the technical field of energy conservation and emission reduction, and in particular to a thermal power unit coupled with molten salt energy storage deep peak regulation system and method thereof. Background Art

[0002] The gas-steam combined cycle has become the fastest growing form of power generation in the world due to its advantages of high power generation efficiency, short construction period, and convenient operation. This also has important guiding significance for the current adjustment of my country's power structure. However, when the combined cycle unit participates in the peak load regulation of the power grid, the operating load fluctuates frequently with the fluctuation of power load and new energy power, resulting in a significant reduction in the efficiency of the combined cycle unit. For example, compared with the full load operation, the heat consumption increases by 8% when the unit load rate is 60% when the unit is running at low load, and increases by 20% when the unit load rate is 40%. Therefore, it is very important to integrate energy storage devices in the combined cycle system to ensure that the unit can still operate at a higher load when participating in power peak regulation, so as to improve 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 in the world with its advantages of 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 particular, for ternary molten salts with a maximum operating temperature below 500°C, it is more suitable for thermal power coupled molten salt energy storage peak-shaving systems that achieve efficient utilization of flue gas waste heat. In related technologies, molten salt energy storage is coupled with peak-shaving in the field of flue gas waste heat utilization. High-temperature flue gas directly heats low-temperature molten salt into high-temperature molten salt. However, due to the large heat exchange temperature difference, serious irreversible losses are generated; and the use of high-temperature molten salt to produce low-parameter steam for heating also causes high-grade molten salt heat losses. Summary of the invention

[0004] The purpose of the present invention is to provide a deep peak-shaving system and method for a thermal power unit coupled with molten salt energy storage, which realizes the high-efficiency step-by-step utilization of high-temperature flue gas waste heat and high-temperature molten salt heat, greatly reduces the heat exchange temperature difference, reduces irreversible losses, and increases the output of high-quality steam. After the steam is output, it continues to act on the steam turbine unit, which also greatly improves the ability of the steam turbine unit to generate power.

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

[0006] A thermal power unit coupled with molten salt energy storage deep peak regulation system, comprising:

[0007] A circulating power generation mechanism, comprising a steam turbine unit and a waste heat utilization device, wherein the steam generated by the waste heat utilization device enters the steam turbine unit to perform work and generate electricity, and the waste heat utilization device comprises a feed water heater;

[0008] A molten salt energy storage mechanism, including an energy storage component, an electrically heated molten salt heater, a molten salt bypass pipe, an electrically heated steam superheater, a steam bypass pipe, a high-temperature molten salt storage tank, 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 feedwater pump;

[0009] Wherein, the molten salt bypass pipe is arranged between the molten salt inlet and the molten salt outlet of the electrically heated molten salt heater, the molten salt outlet of the energy storage component is connected to the molten salt inlet of the electrically heated molten salt heater, the molten salt outlet of the electrically heated 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, and the molten salt outlet of the low-pressure steam generator is connected to the molten salt inlet of the energy storage component;

[0010] The steam bypass pipe is arranged between the steam inlet and the steam outlet of the electrically heated steam superheater, the feedwater outlet of the feedwater heater is respectively connected to the feedwater inlets of the high-pressure steam generator and the low-pressure steam generator, the feedwater inlet of the high-pressure steam generator is installed with the first feedwater 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 inlet of the electrically heated steam superheater, the steam outlet of the electrically heated steam superheater is connected to the steam turbine unit and high-pressure steam enters the steam turbine unit to perform 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 and low-pressure steam enters the steam turbine unit to perform work and generate electricity.

[0011] Preferably, the molten salt energy storage mechanism also includes a secondary feed water heater, the feed water outlet of the feed water heater is connected to the feed water inlet of the secondary feed water heater, and the feed water outlet of the secondary feed water heater is respectively connected to the feed water inlets of the high-pressure steam generator and the low-pressure steam generator; the molten salt outlet of the low-pressure steam generator is connected to the molten salt inlet of the secondary feed water heater, and the molten salt outlet of the secondary feed water heater is connected to the molten salt inlet of the low-temperature molten salt storage tank.

[0012] Preferably, the circulating power generation mechanism also includes a circulating water supply system, which includes a condensate pump, a deaerator, a condensate storage tank, a circulating water pump, a condensate pipe and a condenser. 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 water inlet of the feed water heater, 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 energy storage component includes a low-temperature molten salt storage tank, a low-temperature molten salt pump, a primary molten salt heater and a secondary molten salt heater. The low-temperature molten salt pump is installed at the molten salt outlet of the low-temperature molten salt storage tank, 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 electrically heated molten salt heater, and 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.

[0014] Preferably, the waste heat utilization device also 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 feedwater pump. The high-pressure superheater, the high-pressure steam drum, the low-pressure superheater, the low-pressure steam drum and the feedwater heater are sequentially arranged in the waste heat boiler along the flow direction from the flue gas inlet to the flue gas outlet. The feedwater outlet of the feedwater heater is respectively connected to the feedwater inlets of the low-pressure steam drum and the high-pressure steam drum. The feedwater inlet of the high-pressure steam drum is installed with the second feedwater pump. 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 and high-pressure steam enters the steam turbine unit to perform 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 and low-pressure steam enters the steam turbine unit to perform work and generate electricity.

[0015] Preferably, the energy storage component includes a primary molten salt heater and a secondary molten salt heater, both of which are arranged in the waste heat boiler, the primary molten salt heater is located between the low-pressure superheater and the low-pressure steam drum, the secondary molten salt heater is located between the high-pressure steam drum and the low-pressure superheater, or the secondary molten salt heater is located between the high-pressure superheater and the high-pressure steam drum.

[0016] Preferably, the cycle power generation mechanism also includes a gas turbine unit, which includes a gas turbine compressor, a gas turbine combustion chamber, a gas turbine turbine, and a first generator; the exhaust port of the gas turbine compressor is connected to the air inlet of the gas turbine combustion chamber, the exhaust port of the gas turbine combustion chamber is connected to the air inlet of the gas turbine turbine, the gas turbine turbine drives the first generator to generate electricity, and the exhaust port of the gas turbine turbine is connected to the air inlet of the waste heat boiler.

[0017] Preferably, the steam turbine unit includes medium- and high-pressure cylinders, a low-pressure cylinder, a second generator and a connecting pipe, the steam outlet of the electrically heated steam superheater is connected to the steam inlet of the medium- and high-pressure cylinders, 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 utilization device is respectively connected to the steam inlets of the medium- and high-pressure cylinders and the low-pressure cylinder, the steam outlet of the medium- and high-pressure cylinders is connected to the steam inlet of the low-pressure cylinder through the connecting pipe, the medium- and high-pressure cylinders and the low-pressure cylinder are both coaxially connected to the second generator, and the medium- and high-pressure cylinders and the low-pressure cylinder simultaneously work to drive the second generator to generate electricity.

[0018] The present invention also provides a method for coupling the thermal power unit with the molten salt energy storage deep peak regulation system, comprising the following steps:

[0019] Determining whether the system participates in power peak regulation;

[0020] If the system participates in power peak regulation, determining whether it is necessary to reduce or increase the output power load;

[0021] If the output power load needs to be reduced, part of the flue gas waste heat is used to heat the waste heat utilization device to generate steam, and the steam of the waste heat utilization device drives the steam turbine unit to work and generate electricity, and the other part of the flue gas waste heat is used to heat the low-temperature molten salt in the molten salt energy storage mechanism for heat storage; if the output power load needs to be further reduced, the low-temperature molten salt in the molten salt energy storage mechanism needs to be further heated to a preset temperature by an electrically heated molten salt heater;

[0022] If the output electrical load needs to be increased, all the waste heat of the flue gas will be used to heat the waste heat utilization device to generate steam, and the steam from the waste heat utilization device will drive the steam turbine unit to work and generate electricity; if the output electrical load needs to be further increased, it is also necessary to supplement the feed water to the molten salt energy storage mechanism through the feed water heater, and the molten salt energy storage mechanism will release heat to heat the feed water supplemented by the feed water heater into steam, and the steam from the molten salt energy storage mechanism will also be used to drive the steam turbine unit to work and generate electricity.

[0023] Preferably, if the output power load needs to be further reduced, the low-temperature molten salt in the molten salt energy storage mechanism needs to be further heated to a preset temperature by an electrically heated molten salt heater. The specific steps are as follows: after the low-temperature molten salt is step-heated in the energy storage component, it enters the electrically heated molten salt heater and is heated to a preset temperature to obtain high-temperature molten salt, and then the high-temperature molten salt is sent to a high-temperature molten salt storage tank for storage;

[0024] If the output power load is to be further increased, the specific steps are as follows: the high-temperature molten salt outputted from the high-temperature molten salt storage tank is sequentially cooled by a high-pressure steam superheater, a high-pressure steam generator, a low-pressure steam superheater and a low-pressure steam generator 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 judging whether the high-pressure steam parameter output by the high-pressure steam superheater reaches a preset value; when the high-pressure steam parameter is lower than the preset value, the high-pressure steam enters the electrically heated steam superheater to continue to be heated to a preset temperature, and finally enters the steam turbine unit to perform work and generate electricity; when the high-pressure steam parameter reaches the preset value, the high-pressure steam directly enters the steam turbine unit to perform work and generate electricity, and the low-pressure steam generated by the low-pressure steam generator enters the low-pressure steam superheater for further heating, and then the low-pressure steam enters the steam turbine unit to perform work and generate electricity.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The above technical solution provides a thermal power unit coupled with a molten salt energy storage deep peak-shaving system, which compensates for the shortcomings of low thermal energy grade or insufficient thermal energy of the high-temperature molten salt output from the high-temperature molten salt storage tank through an electrically heated steam superheater, and better ensures that the steam parameters output by the high-pressure steam superheater meet the needs of the steam turbine unit; when the high-temperature flue gas waste heat is insufficient, the electrically heated molten salt heater can ensure the temperature of the molten salt stored in the high-temperature molten salt storage tank, and can further reduce the on-grid power load of the circulating power generation mechanism, increase the minimum load depth of power peak-shaving, and fully meet the peak-shaving needs of the power grid.

[0027] After the low-temperature molten salt is heated in stages by the primary molten salt heater and the secondary molten salt heater, it is stored in the high-temperature molten salt storage tank, which realizes the high-temperature flue gas waste heat of the high-temperature step-by-step efficient utilization and greatly reduces the heat exchange temperature difference; secondly, the high-temperature molten salt is cooled in stages by the high-pressure steam superheater, the high-pressure steam generator, the low-pressure steam superheater and the low-pressure steam generator in turn, and 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, and the distribution positions of various heat exchangers utilizing the heat of the high-temperature molten salt are reasonably designed, and different parameter steam based on the step-by-step matching of energy grade is efficiently produced, so as to realize the high-temperature molten salt heat of the high-temperature step-by-step efficient utilization, greatly reduce the heat exchange temperature difference, and reduce irreversible losses; the feedwater heater is used to supplement the feedwater flow required for steam production when the molten salt energy storage mechanism releases heat, thereby increasing the output of high-quality steam, and the steam continues to act on the steam turbine unit after output, which also greatly improves the ability of the steam turbine unit to generate power. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram of a thermal power unit coupled with a molten salt energy storage deep peak regulation system according to the present invention;

[0029] Figure 2 A schematic diagram of the system in one embodiment of the present invention;

[0030] Figure 3 is a schematic diagram of the system in another embodiment of the present invention;

[0031] Figure 4 FIG. 4 is a schematic diagram of the system in yet another embodiment of the present invention.

[0032] Description of reference numerals:

[0033] 10. Waste heat utilization device; 101. Feed water heater; 102. Waste heat boiler; 103. Low-pressure drum; 104. Low-pressure superheater; 105. High-pressure drum; 106. High-pressure superheater; 107. Second feed water pump;

[0034] 20. Steam turbine unit; 201. Medium and high pressure cylinder; 202. Low pressure cylinder; 203. Second generator; 204. Connecting pipe;

[0035] 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 feedwater pump; 312. Electric-heating molten salt heater; 313. Molten salt bypass pipe; 314. Electric-heating steam superheater; 315. Steam bypass pipe; 316. Secondary feedwater heater;

[0036] 40. Circulating water supply system; 401. Condensate pump; 402. Deaerator; 403. Condensate storage tank; 404. Circulating water pump; 405. Condensate pipe; 406. Condenser;

[0037] 50. Gas turbine unit; 501. Gas turbine compressor; 502. Gas turbine combustion chamber; 503. Gas turbine turbine; 504. First generator;

[0038] 601, valve number one; 602, valve number two; 603, valve number three; 604, valve number four; 605, valve number five; 606, valve number six; 607, valve number seven; 608, valve number eight; 609, valve number nine; 610, valve number ten; 611, valve number eleven; 612, valve number twelve; 613, valve number thirteen; 614, valve number fourteen; 615, valve number fifteen; 616, valve number sixteen; 617, valve number seventeen; 618, valve number eighteen; 619, valve number nineteen; 620, valve number twenty; 621, valve number twenty-one; 622, valve number twenty-two; 623, valve number twenty-three. DETAILED DESCRIPTION

[0039] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are 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 cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0041] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] In an embodiment of the present invention, a deep peak-shaving system and method for a thermal power unit coupled with a molten salt energy storage are provided. When the thermal energy grade of the high-temperature molten salt outputted from the high-temperature molten salt storage tank 302 is low or the thermal energy is insufficient, the system can ensure that the steam parameters outputted by the high-pressure steam superheater 307 meet the requirements of the steam turbine unit 20 through the electrically heated steam superheater 314; when the high-temperature flue gas waste heat is insufficient, the electrically heated molten salt heater 312 can ensure the temperature of the molten salt stored in the high-temperature molten salt storage tank 302; secondly, the high-temperature flue gas waste heat and the high-temperature molten salt heat are efficiently utilized in a stepped manner, which greatly reduces the heat exchange temperature difference and the irreversible loss, and can also supplement the feed water flow required for producing steam when the molten salt energy storage mechanism 30 releases heat, thereby increasing the output of high-quality steam and applying the steam to the steam turbine unit 20, thereby greatly improving the ability of the steam turbine unit 20 to generate power.

[0043] It should be noted that either the electrically heated molten salt heater 312 or the electrically heated steam superheater 314 is used selectively.

[0044] See also Figure 1 and Figure 3 In one embodiment, the system at least comprises: a cycle power generation mechanism, the cycle power generation mechanism comprises a gas turbine unit 50, the gas turbine unit 50 comprises 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 air inlet of the gas turbine combustion chamber 502, the exhaust port of the gas turbine combustion chamber 502 is connected to the air inlet of the gas turbine turbine 503, the exhaust port of the gas turbine turbine 503 drives the first generator 504 to generate electricity, and the exhaust port of the gas turbine turbine 503 is connected to the air inlet of the waste heat boiler 102. The gas discharged from the gas turbine turbine 503 is flue gas, and the present invention improves the power peak-shaving capacity of the thermal power unit by utilizing the waste heat of the flue gas.

[0045] In order to utilize the waste heat of the flue gas, the circulating power generation mechanism also includes a steam turbine unit 20, a waste heat utilization device 10 and a circulating water supply system 40. The steam generated by the waste heat utilization device 10 enters the steam turbine unit 20 to perform work and generate electricity; the system also includes a molten salt energy storage mechanism 30.

[0046] 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. 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 utilization device 10 is connected to the steam inlets of the medium-high pressure cylinder 201 and the low pressure cylinder 202 respectively. 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 simultaneously work to drive the second generator 203 to generate electricity.

[0047] The circulating water supply system 40 includes a condensate pump 401 , a deaerator 402 , a condensate storage tank 403 , a circulating water pump 404 , a condensate pipe 405 and a condenser 406 .

[0048] The waste heat utilization device 10 includes a feed water heater 101, 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.

[0049] Circuit 1: In order to use the high-temperature flue gas from the gas turbine 503 to heat the feed water to produce steam, and then the steam enters the steam turbine unit 20 to generate power. Open and adjust valve No. 1 601, valve No. 2 602, valve No. 6 606, valve No. 8 608, valve No. 9 609, valve No. 10 610 and valve No. 21 621, the feed water is heated by the feed water heater 101 and then divided into two feed water paths, and the feed water outlet of the feed water heater 101 is connected to the feed water inlet of the low-pressure drum 103 and the high-pressure drum 105 respectively.

[0050] One of the branches: a valve No. 1 601 is installed at the feed water inlet of the low-pressure drum 103, the steam outlet of the low-pressure drum 103 is connected to the steam inlet of the low-pressure superheater 104, the low-pressure steam generated by the low-pressure drum 103 enters the low-pressure superheater 104 for further heating, a valve No. 6 606 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, and the steam of the low-pressure superheater 104 directly enters the low-pressure cylinder 202 of the steam turbine to perform work. Another branch: The feed water inlet of the high-pressure drum 105 is installed with a second feed water pump 107 and a second valve 602. The feed water entering the high-pressure drum 105 is first pressurized by the first feed water pump. The steam outlet of the high-pressure drum 105 is connected to the steam inlet of the high-pressure superheater 106. The high-pressure steam generated by the high-pressure 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 medium and high-pressure cylinder 201. The steam outlet of the high-pressure superheater 106 is connected to the steam inlet of the medium and high-pressure cylinder 201. A No. 9 valve 609 is installed at the inlet, and the steam in the high-pressure superheater 106 enters the medium- and high-pressure cylinders 201 and the low-pressure cylinder 202 of the steam turbine in turn to perform work. A No. 10 valve 610 is installed at the steam inlet of the medium- and high-pressure cylinder 201, and the steam outlet of the medium- and high-pressure cylinder 201 is connected to the steam inlet of the low-pressure cylinder 202 through a connecting pipe 204, and a No. 8 valve 608 is installed on the connecting pipe 204. The medium- and high-pressure cylinders 201 and the low-pressure cylinder 202 perform work at the same time to drive the second generator 203 to generate electricity.

[0051] The steam outlet of the low-pressure cylinder 202 is connected to the exhaust steam inlet of the condenser 406, and the condensate 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 and the No. 21 valve 621 are installed in sequence on the condensate pipe 405 along the water flow direction, and the water outlet of the deaerator 402 is connected to the feed water inlet of the feed water heater 101, thereby forming a loop one.

[0052] As a preferred embodiment, the condensate storage tank 403 is used to meet the condensate demand of the system when participating in power peak regulation. The outlet of the condensate pump 401 is connected to the water inlet of the condensate storage tank 403, and a valve No. 22 622 is installed at the water inlet of the condensate storage tank 403. The outlet of the condensate storage tank 403 is connected to the water inlet of the deaerator 402. The outlet of the condensate storage tank 403 is installed with a circulating water pump 404 and a valve No. 23 623, and the outlet of the deaerator 402 is connected to the water inlet of the feed water heater 101.

[0053] It can be understood that when the system participates in power peak regulation and needs to reduce the output power load, valve No. 21 621 and valve No. 22 622 are opened and adjusted, and valve No. 23 623 is closed to reduce the amount of condensate delivered to the deaerator 402 through the condensate pump 401. The excess condensate from the condensate pump 401 is directly delivered to the condensate storage tank 403 for storage, thereby reducing the parameters of the superheated steam delivered from the waste heat boiler 102 to the steam turbine unit 20, reducing the working capacity of the steam turbine unit 20, and thereby reducing the power load output by the second generator 203 to meet the power peak regulation demand.

[0054] When the system participates in power peak regulation and needs to increase the output power load, open and adjust valve No. 21 621 and valve No. 23 623, close valve No. 22 622, and the condensate storage tank 403 replenishes the insufficient condensate of the system. When the system participates in power peak regulation and needs to continue to increase the output power load, it can also replenish the water supply required for producing steam when the molten salt energy storage mechanism 30 releases heat.

[0055] Specific implementation method of the molten salt energy storage mechanism 30: The molten salt energy storage mechanism 30 includes an energy storage component, an electrically heated molten salt heater 312, a molten salt bypass pipe 313, an electrically heated steam superheater 314, a steam bypass pipe 315, a high-temperature molten salt storage tank 302, 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 energy storage component includes a low-temperature molten salt storage tank 301, a low-temperature molten salt pump 305, a primary molten salt heater 303 and a secondary molten salt heater 304.

[0056] like Figure 1-Figure 3 As shown, the secondary molten salt heater 304 and the primary molten salt heater 303 are both arranged in the waste heat boiler 102, the primary molten salt heater 303 is located between the low-pressure superheater 104 and the low-pressure drum 103, and the secondary molten salt heater 304 is located between the high-pressure drum 105 and the low-pressure superheater 104. According to the principles of temperature matching and cascade utilization, the heat exchange equipment in the waste heat boiler 102 is reasonably arranged to achieve cascade efficient utilization of flue gas waste heat.

[0057] Loop 2: The molten salt energy storage mechanism 30 stores energy or releases heat.

[0058] like Figure 1 , Figure 2 As shown, when the system participates in power peak regulation and needs to reduce the output power load, in order to keep the steam turbine unit 20 running at a low load, a portion of the flue gas waste heat from the gas turbine 503 needs to be stored in the molten salt energy storage mechanism 30. Specifically, valve No. 11 611, valve No. 14 614 and valve No. 15 615 are opened and adjusted.

[0059] A low-temperature molten salt pump 305 and a No. 11 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 low-pressure drum 103 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 through the molten salt bypass pipe 313, a No. 14 valve 614 is installed on the molten salt bypass pipe 313, and a No. 15 valve 615 is installed at the molten salt inlet of the high-temperature molten salt storage tank 302.

[0060] It is understandable that the low-temperature molten salt in the low-temperature molten salt storage tank 301, driven by the low-temperature molten salt pump 305, enters the primary molten salt heater 303 and the secondary molten salt heater 304 in turn to be heated in stages to obtain high-temperature molten salt, which is then sent to the high-temperature molten salt storage tank 302 for storage, that is, the high-temperature flue gas waste heat is stored, achieving high-efficiency step-by-step utilization of the high-temperature flue gas waste heat, greatly reducing the heat exchange temperature difference, and reducing irreversible losses. The use of the molten salt energy storage mechanism 30 to store the high-temperature flue gas waste heat avoids the priority choice of reducing the operating load of the gas turbine unit 50, and largely ensures the high-efficiency operation of the cycle power generation mechanism.

[0061] When the system participates in power peak regulation and needs to continue to 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 continuing to increase the output power load of the system.

[0062] Specifically, the molten salt outlet of the high-temperature molten salt storage tank 302 is installed with a high-temperature molten salt pump 306 and a No. 16 valve 616, 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 secondary feed water heater 316, the molten salt outlet of the secondary feed water heater 316 is connected to the molten salt inlet of the low-temperature molten salt storage tank 301, and a No. 17 valve 617 is installed at the molten salt inlet of the low-temperature molten salt storage tank 301.

[0063] It can be understood that the high-temperature molten salt output from the high-temperature molten salt storage tank 302 is sequentially cooled by the high-pressure steam superheater 307, the high-pressure steam generator 308, the low-pressure steam superheater 309, the low-pressure steam generator 310 and the secondary feed water heater 316 to obtain low-temperature molten salt and store it 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 energy cascade utilization, the distribution positions of various types of heat exchangers utilizing the heat of high-temperature molten salt are reasonably designed, and steam with different parameters based on energy grade cascade matching is efficiently produced, and the heat stored in the high-temperature molten salt storage tank 302 is released, which not only realizes the cascade efficient utilization of high-temperature molten salt heat, greatly reduces the heat exchange temperature difference, further reduces the irreversible loss, and increases the output of high-quality steam, which greatly improves the working capacity of the steam turbine unit. The heat released by 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 to generate electricity, so as to further increase the operating load of the steam turbine unit 20, thereby continuing to increase the output electrical load of the system. The secondary feedwater heater 316 is set up to further utilize the molten salt heat in a step-by-step manner. When heat is released by producing steam, the heat released can be increased, thereby increasing the heat storage and release capacity of the molten salt energy storage mechanism.

[0064] like Figure 1 , Figure 2 As shown, loop three: when the system participates in power peak regulation and needs to continue to 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 continuing to increase the output power load of the system. Specifically, open and adjust valve No. 3 603, valve No. 4 604, valve No. 5 605, valve No. 7 607, valve No. 8 608, valve No. 10 610, valve No. 16 616, valve No. 17 617, valve No. 18 618 and valve No. 19 619, and close valve No. 11 611 and valve No. 15 615. After being heated by the feedwater heater 101, the feedwater enters the secondary feedwater heater 316 for secondary preheating and is divided into two feedwater routes. The secondary feedwater heater 316 is connected to the feedwater inlet of the high-pressure steam generator 308 and the low-pressure steam generator 310 respectively.

[0065] One of the branches: the first feed water pump 311 and the No. 5 valve 605 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 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 electric-heating steam superheater 314, the steam inlet of the electric-heating steam superheater 314 is installed with the No. 18 valve 618, and the steam outlet is installed with the No. 19 valve 619, the steam outlet of the electric-heating steam superheater 314 is connected to the steam inlet of the medium and high-pressure cylinder 201, and the steam enters the medium and high-pressure cylinder 201 and the low-pressure cylinder 202 in turn to do work. Another branch: The steam inlet of the low-pressure steam generator 310 is installed with a No. 4 valve 604, and 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 enters the low-pressure steam superheater 309 for further heating. The steam outlet of the low-pressure steam superheater 309 is installed with a No. 7 valve 607, and the steam outlet of the low-pressure steam superheater 309 is connected to the steam inlet of the low-pressure cylinder 202. The steam of the low-pressure steam superheater 309 directly enters the low-pressure cylinder 202 of the steam turbine to perform work. The medium and high-pressure cylinders 201 and the low-pressure cylinder 202 perform work at the same time to drive the second generator 203 to generate electricity.

[0066] It is understandable that the feedwater heater 101 in loop three is divided into two feedwater routes after secondary preheating by the secondary feedwater heater 316, which supplements the feedwater flow required for producing steam when the molten salt energy storage mechanism 30 releases heat, thereby increasing the output of high-quality steam. At the same time, when the system participates in power peak regulation and needs to continue to increase the output power load, loop three and loop one work together on the steam turbine unit 20, and the steam output of the two loops acts on the steam turbine unit 20, which greatly improves the ability of the steam turbine unit 20 to work and generate electricity. The electrically heated steam superheater 314 makes up for the shortcomings of the low thermal energy grade or insufficient thermal energy of the high-temperature molten salt output by the high-temperature molten salt storage tank 302, and better ensures that the steam parameters output by the high-pressure steam superheater 307 meet the needs of the steam turbine unit 20.

[0067] It should be noted that in loop two and loop three, the electrically heated molten salt heater 312 is turned off and the electrically heated steam superheater 314 is turned on. At this time, the temperature of the low-temperature molten salt in the low-temperature molten salt storage tank 301 can be 150-200°C, and the temperature of the molten salt stored in the high-temperature molten salt storage tank 302 can be 450-500°C.

[0068] like Figure 1 , Figure 3As shown, in another embodiment, the main difference is: when the combined cycle power generation system participates in power peak regulation and needs to continue to reduce the output power load, the gas turbine unit 50 and the steam turbine unit 20 both maintain low load operation, a portion of the flue gas waste heat from the gas turbine turbine 503 is stored in the molten salt energy storage mechanism 30, and valve No. 11 611, valve No. 15 615, valve No. 12 612 and valve No. 13 613 are opened and adjusted.

[0069] Specifically, the molten salt outlet of the secondary molten salt heater 304 is connected to the molten salt inlet of the electrically heated molten salt heater 312, and the molten salt outlet of the electrically heated molten salt heater 312 is connected to the molten salt inlet of the high-temperature molten salt storage tank 302. The molten salt inlet of the electrically heated molten salt heater 312 is installed with valve No. 12, and its molten salt outlet is installed with valve No. 13.

[0070] It can be understood that the high-temperature flue gas from the gas turbine 503 is first used to heat the feed water in the waste heat utilization device 10 to generate steam, and the steam is used to drive the steam turbine unit 20 to generate power, and then used to heat the molten salt for heat storage. At this time, the high-temperature flue gas has insufficient waste heat, so that the low-temperature molten salt cannot be heated to the set temperature by the high-temperature flue gas. The low-temperature molten salt in the low-temperature molten salt storage tank 301 enters the primary molten salt heater 303 and the secondary molten salt heater 304 in turn to be heated in stages, and then enters the electric heating molten salt heater 312 to use electric energy to further heat the molten salt to the set temperature, and then returns to the high-temperature molten salt storage tank 302 for storage. Therefore, the molten salt is supplemented with electric energy by the electrically heated molten salt heater 312, which not only makes up for the lack of waste heat of the high-temperature flue gas and ensures the molten salt temperature required for the molten salt energy storage mechanism 30 to store heat, but also consumes a part of the output electric load through the electrically heated molten salt heater 312 to meet the load reduction demand of power peak regulation, so that the operating load of the gas turbine unit 50 participating in power peak regulation is relatively reduced, further effectively ensuring the high-efficiency operation of the circulating power generation mechanism.

[0071] In this embodiment, the circuit from the high temperature molten salt storage tank 302 to the low temperature molten salt storage tank 301 refers to the corresponding technical solution in the circuit 2 of the previous embodiment, and combined with the circuit 3 in the previous embodiment, it should be noted that the valve No. 18 618 and the valve No. 19 619 in the circuit 3 are closed, and the valve No. 20 620 is opened. Specifically, the steam bypass pipe 315 is arranged between the steam inlet and the steam outlet of the electric heating steam superheater 314, and the valve No. 20 620 is installed on the steam bypass pipe 315.

[0072] That is, the electrically heated molten salt heater 312 is turned on and the electrically heated steam superheater 314 is turned off. At this time, the temperature of the molten salt stored in the high-temperature molten salt storage tank 302 can be 600° C. or above.

[0073] See also Figure 4 In yet another embodiment, the main difference is that the secondary molten salt heater 304 is located between the high-pressure superheater 106 and the high-pressure steam drum 105, which has a similar technical effect to the previous embodiment.

[0074] Please continue reading Figure 1-Figure 4 In an embodiment of the present invention, there is also provided a method for coupling a thermal power unit with a molten salt energy storage deep peak regulation system as claimed in claim 1, comprising the following steps:

[0075] Determine whether the system participates in power peak regulation.

[0076] If the system does not participate in power peak regulation, the gas turbine unit 50 and the steam turbine unit 20 both maintain high load operation to ensure the high efficiency operation of the circulating power generation mechanism. The high-temperature flue gas from the gas turbine 503 is all used to heat the feed water to produce steam, and then enters the steam turbine unit 20 to generate power. At this time, open and adjust valve No. 1 601, valve No. 2 602, valve No. 6 606, valve No. 8 608, valve No. 9 609, valve No. 10 610 and valve No. 21 621. The feed water from the deaerator 402 is heated by the feed water heater 101 and then divided into two feed water routes, which enter the low-pressure drum 103 and the high-pressure drum 105 respectively. The feed water entering the high-pressure drum 105 is first pressurized by the second feed water pump 107, and the high-pressure steam generated by the high-pressure drum 105 enters the high-pressure superheater 106 for further heating, and then enters the medium-pressure cylinder 201 and the low-pressure cylinder 202 in sequence to perform work; the low-pressure steam generated by the low-pressure drum 103 enters the low-pressure superheater 104 for further heating, and then directly enters the low-pressure cylinder 202 to perform work, and the medium-pressure cylinder 201 and the low-pressure cylinder 202 perform work at the same time to drive the second generator 203 to generate electricity, and the exhaust steam generated after the steam turbine unit 20 performs work enters the condenser 406 to form condensate, and then returns to the deaerator 402 through the condensate pump 401.

[0077] If the system participates in power peak regulation, determine whether it is necessary to reduce or increase the output power load.

[0078] If it is necessary to reduce the output power 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 turbine 503 is used to heat the waste heat utilization device 10 to generate steam. The steam of the waste heat utilization device 10 drives the steam turbine unit 20 to 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 maintain the high-load operation of the gas turbine unit 50. At this time, the heat storage of the molten salt energy storage mechanism 30 is used to store the excess high-temperature flue gas waste heat, thereby ensuring the high-efficiency operation of the cycle power generation mechanism and avoiding the direct emission loss of flue gas waste heat.

[0079] Specifically, open and adjust valve No. 21 621 and valve No. 22 622, and close valve No. 23 623 to reduce the amount of condensate delivered to the deaerator 402 through the condensate pump 401. The excess condensate from the condensate pump 401 is directly delivered to the condensate storage tank 403 for storage, which in turn reduces the feed water flow from the deaerator 402 to the waste heat boiler 102, thereby reducing the superheated steam flow from the waste heat boiler 102 to the steam turbine unit 20, reducing the working capacity of the steam turbine unit 20, and thereby reducing the electrical load output by the second generator 203 to meet the power peak regulation demand.

[0080] Open and adjust valve No. 11 611, valve No. 14 614 and valve No. 15 615. Driven by the low-temperature molten salt pump 305, the low-temperature molten salt in the low-temperature molten salt storage tank 301 enters the primary molten salt heater 303 and the secondary molten salt heater 304 in turn to be heated into high-temperature molten salt. The high-temperature molten salt returns to the high-temperature molten salt storage tank 302 through the molten salt bypass pipe 313 for storage, thereby storing the high-temperature flue gas waste heat through the molten salt energy storage system. The high-temperature flue gas waste heat is efficiently utilized in stages, greatly reducing the heat exchange temperature difference and reducing irreversible losses. The use of the molten salt energy storage mechanism 30 to store the high-temperature flue gas waste heat avoids the priority choice of reducing the operating load of the gas turbine unit 50, and largely ensures the high-efficiency operation of the cycle power generation mechanism.

[0081] If the system participates in power peak regulation and needs to continue to reduce the output power load, the steam turbine unit 20 and the gas turbine unit 50 need to maintain low-load operation. Since the power load output by the gas turbine unit 50 is also reduced, the flue gas waste heat is insufficient, and the low-temperature molten salt in the molten salt energy storage mechanism 30 needs to be further heated to a preset temperature by the electrically heated molten salt heater 312; it can be understood that the operation load of the gas turbine unit 50 and the steam turbine unit 20 is reduced at the same time. At this time, the molten salt energy storage mechanism 30 is used to store the excess high-temperature flue gas waste heat, so that the operation load of the thermal power unit is further reduced, and the electrically heated molten salt heater 312 consumes part of the power load for heating the molten salt, which is stored through the molten salt energy storage system, thereby avoiding the operation load of the gas turbine unit 50 being too low, thereby ensuring the operation efficiency of the combined cycle power generation system. At this time, open and adjust valve No. 12 612 and valve No. 13 613, and close valve No. 14 614.

[0082] Specifically, the high-temperature flue gas from the gas turbine 503 is first used to heat the feed water to generate steam to drive the steam turbine unit 20 to generate power. The feed water from the deaerator 402 is heated by the feed water heater 101 and then divided into two feed water paths, which enter the low-pressure steam drum 103 and the high-pressure steam drum 105 respectively, and finally act on the medium- and high-pressure cylinders 201 and the low-pressure cylinder 202, so that the medium- and high-pressure cylinders 201 and the low-pressure cylinder 202 work at the same time to drive the second generator 203 to generate power. The specific cycle loop will not be repeated here, and please refer to the above system when it does not participate in power peak regulation.

[0083] The high-temperature flue gas from the gas turbine 503 is then used to heat the molten salt for heat storage. When the gas turbine unit 50 is running at a low load, the flue gas flow and temperature will decrease. Therefore, the high-temperature flue gas has insufficient waste heat, so that the molten salt cannot be heated to the set temperature by the high-temperature flue gas. The low-temperature molten salt in the low-temperature molten salt storage tank 301 enters the primary molten salt heater 303 and the secondary molten salt heater 304 in turn to be heated in stages, and then enters the electric heating molten salt heater 312 to use electric energy to further heat the molten salt to the set temperature, and then returns to the high-temperature molten salt storage tank 302 for storage.

[0084] If the output electrical load needs to be increased, both the gas turbine unit 50 and the steam turbine unit 20 must maintain high load operation to ensure high-efficiency operation of the circulating power generation mechanism. The high-temperature flue gas waste heat from the gas turbine turbine 503 is all used to heat the feed water in the waste heat utilization device 10 to generate steam, and then the steam from the waste heat utilization device 10 drives the steam turbine unit 20 to work and generate electricity.

[0085] Specifically, valve No. 1 601, valve No. 2 602, valve No. 606, valve No. 8 608, valve No. 9 609, valve No. 10 610 and valve No. 21 621 are opened and adjusted, and the feed water from the deaerator 402 is heated by the feed water heater 101 and then divided into two feed water routes, which enter the low-pressure drum 103 and the high-pressure drum 105 respectively, and the feed water entering the high-pressure drum 105 is first pressurized by the second feed water pump 107, and the high-pressure steam generated by the high-pressure drum 105 enters the high-pressure drum 103 and the high-pressure drum 105. The superheater 106 is further heated, and then enters the medium and high pressure cylinder 201 and the low pressure cylinder 202 in turn to perform work; the low pressure steam generated by the low pressure drum 103 enters the low pressure superheater 104 for further heating, and then directly enters the low pressure cylinder 202 to perform work, and the medium and high pressure cylinder 201 and the low pressure cylinder 202 perform work at the same time to drive the second generator 203 to generate electricity, and the exhaust steam generated after the turbine unit 20 performs work enters the condenser 406 to form condensate, and then returns to the deaerator 402 through the condensate pump 401.

[0086] If the output electrical load is to be further increased, not only the gas turbine unit 50 and the steam turbine unit 20 need to maintain high load operation, but also the molten salt energy storage mechanism 30 needs to release heat to heat the feed water added by the feed water heater 101 into steam. The generated steam is used to drive the steam turbine unit 20 to work and generate electricity, so as to further increase the operating load of the steam turbine unit 20 and further increase the output electrical load. After heating, the feed water heater 101 is divided into two feed waters, which continue to enter the low-pressure drum 103 and the high-pressure drum 105 respectively, and finally work and generate electricity in the steam turbine unit 20. The specific steps will not be repeated.

[0087] In addition, the following steps are required: open and adjust valve No. 3 603, valve No. 4 604, valve No. 5 605, valve No. 7 607, valve No. 8 608, valve No. 10 610, valve No. 16 616, valve No. 17 617, valve No. 18 618 and valve No. 19 619, and close valve No. 11 611, valve No. 15 615 and valve No. 20.

[0088] After the feed water from the deaerator 402 is heated by the feed water heater 101, the steam is further heated to a preset temperature by the secondary feed water heater 316. The feed water from the secondary feed water heater 316 enters the low-pressure steam generator 310 and the high-pressure steam generator 308 respectively. Before entering the high-pressure steam generator 308, the feed water is pressurized by the first feed water pump 311. The high-pressure steam generated by the high-pressure steam generator 308 enters the high-pressure steam superheater 307 for further heating. Then, it is determined whether the high-pressure steam parameter output by the high-pressure steam superheater 307 reaches the preset value. When the high-pressure steam parameter is lower than the preset value, the The high-pressure steam then enters the electric heating steam superheater 314 to continue heating to the preset temperature, and then enters the medium and high pressure cylinder 201 and the low pressure cylinder 202 in turn to perform work. When the high-pressure steam parameter reaches the preset value, the high-pressure steam enters the medium and high pressure cylinder 201 and the low pressure cylinder 202 in turn to perform 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 to perform work. The medium and high pressure cylinder 201 and the low pressure cylinder 202 perform work at the same time to drive the second generator 203 to generate electricity. The exhaust steam generated by the steam turbine unit 20 after performing work enters the condenser 406 to form condensed water. Open and adjust valve No. 21 621 and valve No. 23 623, close valve No. 22 622, and use the condensed water storage tank 403 to supplement the feed water flow required for producing steam when the molten salt energy storage mechanism 30 releases heat. The secondary feed water heater 316 is connected to the high-pressure steam generator 308 and the low-pressure steam generator 310 to supplement the feed water flow required to produce steam when the molten salt energy storage mechanism 30 releases heat, thereby increasing the output of high-quality steam.

[0089] In addition, the high-temperature molten salt output from the high-temperature molten salt storage tank 302 is sequentially cooled through the high-pressure steam superheater 307, the high-pressure steam generator 308, the low-pressure steam superheater 309, the low-pressure steam generator 310 and the secondary feed water heater 316 to obtain low-temperature molten salt and store it in the low-temperature molten salt storage tank 301.

[0090] 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 energy cascade utilization, the distribution positions of various heat exchangers utilizing high-temperature molten salt heat are reasonably designed, and steam with different parameters based on energy grade cascade matching is efficiently produced, and the heat stored in the high-temperature molten salt storage tank 302 is released, which not only realizes the cascade efficient utilization of high-temperature molten salt heat, greatly reduces the heat exchange temperature difference, reduces irreversible losses, and increases the output of high-quality steam, greatly improving the working capacity of the steam turbine. The heat released by the high-temperature molten salt storage tank 302 is used together with the heat output from the feedwater 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, so as to further increase the operating load of the steam turbine unit 20, thereby increasing the output electrical load. The electrically heated steam superheater 314 compensates for the disadvantage of low thermal energy quality or insufficient thermal energy of the high-temperature molten salt output by the high-temperature molten salt storage tank 302, and better ensures that the steam parameters output by the high-pressure steam superheater 307 meet the requirements of the steam turbine unit 20.

[0091] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A thermal power unit coupled with molten salt energy storage deep peak regulation system, characterized in that: include: A circulating power generation mechanism, comprising a steam turbine unit and a waste heat utilization device, wherein the steam generated by the waste heat utilization device enters the steam turbine unit to perform work and generate electricity, and the waste heat utilization device comprises a feed water heater; A molten salt energy storage mechanism, including an energy storage component, an electrically heated molten salt heater, a molten salt bypass pipe, an electrically heated steam superheater, a steam bypass pipe, a high-temperature molten salt storage tank, 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 feedwater pump; Wherein, the molten salt bypass pipe is arranged between the molten salt inlet and the molten salt outlet of the electrically heated molten salt heater, the molten salt outlet of the energy storage component is connected to the molten salt inlet of the electrically heated molten salt heater, the molten salt outlet of the electrically heated 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, and the molten salt outlet of the low-pressure steam generator is connected to the molten salt inlet of the energy storage component; The steam bypass pipe is arranged between the steam inlet and the steam outlet of the electrically heated steam superheater, the feedwater outlet of the feedwater heater is respectively connected to the feedwater inlets of the high-pressure steam generator and the low-pressure steam generator, the feedwater inlet of the high-pressure steam generator is installed with the first feedwater 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 inlet of the electrically heated steam superheater, the steam outlet of the electrically heated steam superheater is connected to the steam turbine unit and high-pressure steam enters the steam turbine unit to perform 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 and low-pressure steam enters the steam turbine unit to perform work and generate electricity.

2. The system according to claim 1, characterized in that The molten salt energy storage mechanism also includes a secondary feed water heater, the feed water outlet of the feed water heater is connected to the feed water inlet of the secondary feed water heater, and the feed water outlet of the secondary feed water heater is respectively connected to the feed water inlets of the high-pressure steam generator and the low-pressure steam generator; the molten salt outlet of the low-pressure steam generator is connected to the molten salt inlet of the secondary feed water heater, and the molten salt outlet of the secondary feed water heater is connected to the molten salt inlet of the energy storage component.

3. The system according to claim 1, characterized in that The circulating power generation mechanism also includes a circulating water supply system, which includes a condensate pump, a deaerator, a condensate storage tank, a circulating water pump, a condensate pipe and a condenser. 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 water inlet of the feed water heater, 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.

4. The system according to claim 1, characterized in that The energy storage component includes a low-temperature molten salt storage tank, a low-temperature molten salt pump, a primary molten salt heater and a secondary molten salt heater. The low-temperature molten salt pump is installed at the molten salt outlet of the low-temperature molten salt storage tank, 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 electrically heated molten salt heater, and 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.

5. The system according to claim 1, wherein: The waste heat utilization device also 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 feedwater pump. The high-pressure superheater, the high-pressure steam drum, the low-pressure superheater, the low-pressure steam drum and the feedwater heater are sequentially arranged in the waste heat boiler along the flow direction from the flue gas inlet to the flue gas outlet. The feedwater outlet of the feedwater heater is respectively connected to the feedwater inlets of the low-pressure steam drum and the high-pressure steam drum. The feedwater inlet of the high-pressure steam drum is installed with the second feedwater pump. 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 and high-pressure steam enters the steam turbine unit to perform 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 and low-pressure steam enters the steam turbine unit to perform work and generate electricity.

6. The system according to claim 5, characterized in that The energy storage component includes a primary molten salt heater and a secondary molten salt heater, both of which are arranged in the waste heat boiler, the primary molten salt heater is located between the low-pressure superheater and the low-pressure steam drum, the secondary molten salt heater is located between the high-pressure steam drum and the low-pressure superheater, or the secondary molten salt heater is located between the high-pressure superheater and the high-pressure steam drum.

7. The system according to claim 5, characterized in that The cycle power generation mechanism also includes a gas turbine unit, which includes a gas turbine compressor, a gas turbine combustion chamber, a gas turbine turbine, and a first generator; the exhaust port of the gas turbine compressor is connected to the air inlet of the gas turbine combustion chamber, the exhaust port of the gas turbine combustion chamber is connected to the air inlet of the gas turbine turbine, the gas turbine turbine drives the first generator to generate electricity, and the exhaust port of the gas turbine turbine is connected to the air inlet of the waste heat boiler.

8. The system of claim 1, wherein: The steam turbine unit includes medium- and high-pressure cylinders, a low-pressure cylinder, a second generator and a connecting pipe. The steam outlet of the electrically heated steam superheater is connected to the steam inlet of the medium- and high-pressure cylinders, 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 utilization device is respectively connected to the steam inlets of the medium- and high-pressure cylinders and the low-pressure cylinder, the steam outlet of the medium- and high-pressure cylinders is connected to the steam inlet of the low-pressure cylinder through the connecting pipe, the medium- and high-pressure cylinders and the low-pressure cylinder are both coaxially connected to the second generator, and the medium- and high-pressure cylinders and the low-pressure cylinder simultaneously work to drive the second generator to generate electricity.

9. A method for coupling a thermal power unit with a molten salt energy storage deep peak regulation system as claimed in claim 1, characterized in that: The steps include: Determining whether the system participates in power peak regulation; If the system participates in power peak regulation, determining whether it is necessary to reduce or increase the output power load; If the output power load needs to be reduced, part of the flue gas waste heat is used to heat the waste heat utilization device to generate steam. The steam output by the waste heat utilization device drives the steam turbine unit to work and generate electricity, and the other part of the flue gas waste heat is used to heat the low-temperature molten salt in the molten salt energy storage mechanism for heat storage; if the output power load needs to be further reduced, the low-temperature molten salt in the molten salt energy storage mechanism needs to be further heated to a preset temperature by an electrically heated molten salt heater; If the output electrical load needs to be increased, all the waste heat of the flue gas will be used to heat the waste heat utilization device to generate steam, and the steam output by the waste heat utilization device drives the steam turbine unit to work and generate electricity; if the output electrical load needs to be further increased, it is also necessary to supplement the feed water to the molten salt energy storage mechanism through the feed water heater, and 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 work and generate electricity.

10. The method according to claim 9, characterized in that: If the output power load needs to be further reduced, the low-temperature molten salt in the molten salt energy storage mechanism needs to be further heated to a preset temperature by an electrically heated molten salt heater. The specific steps are as follows: After the low-temperature molten salt is step-heated in the energy storage component, it enters the electrically heated molten salt heater and is heated to a preset temperature to obtain high-temperature molten salt, and then the high-temperature molten salt is sent to a high-temperature molten salt storage tank for storage; If the output power load is to be further increased, the specific steps are as follows: the high-temperature molten salt outputted from the high-temperature molten salt storage tank is sequentially cooled by a high-pressure steam superheater, a high-pressure steam generator, a low-pressure steam superheater and a low-pressure steam generator to obtain low-temperature molten salt and store it in a 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 a 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. Heat, and then determine whether the high-pressure steam parameter output by the high-pressure steam superheater reaches a preset value. When the high-pressure steam parameter is lower than the preset value, the high-pressure steam enters the electrically heated steam superheater to continue to be heated to a preset temperature, and finally enters the steam turbine unit to do work and generate electricity. When the high-pressure steam parameter reaches the preset value, the high-pressure steam directly enters the steam turbine unit to do work and generate electricity, and the low-pressure steam generated by the low-pressure steam generator enters the low-pressure steam superheater for further heating, and then the low-pressure steam enters the steam turbine unit to do work and generate electricity.

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