A high-temperature molten salt energy storage coupled gas power generation peak shaving system and operation method

Abstract

The present invention relates to a high-temperature molten salt energy storage coupled gas power generation peak shaving system and an operation method, which includes a gas turbine generator set, a flue gas heat exchange device, a molten salt energy storage heat exchange device, a steam turbine generator set and a circulating water path; the molten salt energy storage heat exchange device includes a low-temperature molten salt storage tank, a low-temperature molten salt pump, a high-temperature molten salt storage tank, a high-temperature molten salt pump and a molten salt-steam heat exchange mechanism; the flue gas outlet of the gas turbine generator set is communicated with the flue gas inlet of the flue gas heat exchange device, and the low-temperature molten salt storage tank, the flue gas heat exchange device, the high-temperature molten salt storage tank and the molten salt-steam heat exchange mechanism are sequentially communicated to form a circulating energy storage heat exchange loop, and the steam turbine generator set, the molten salt-steam heat exchange mechanism and the circulating water path are sequentially communicated to form a steam cycle power generation loop; a low-temperature molten salt bypass pipe is arranged at the molten salt inlet and the molten salt outlet of the low-temperature molten salt storage tank, and a high-temperature molten salt bypass pipe is arranged at the molten salt inlet of the high-temperature molten salt storage tank and the molten salt outlet of the high-temperature molten salt pump; this system can perform deep peak shaving with a higher peak shaving capacity.

Description

Technical Field

[0001] The present invention relates to the field of thermal power flexibility technology, and in particular to a high-temperature molten salt heat storage coupled gas power generation peak regulation system and an operation method. Background Art

[0002] At present, my country's policies attach great importance to the promotion of new energy electricity and reduce the proportion of thermal power units, which makes the development of thermal power units face severe tests. In the future, thermal power generation will inevitably give way to the development of new energy electricity, which will fundamentally change the main function of thermal power generation, and will transform from the original main power source for power supply guarantee to a flexible and adjustable power source. In recent years, due to the vigorous development of new energy electricity, a high proportion of new energy electricity has been connected to the power grid, resulting in serious "wind and light abandonment" phenomenon, which has brought huge challenges to the safe operation of the power grid and the guarantee of power supply. Therefore, it is urgent to increase the proportion of flexible regulating power sources in the power grid, so as to improve the ability of the power grid to absorb new energy electricity and increase the proportion of clean green electricity in the power grid.

[0003] At present, the gas-steam combined cycle has become the fastest-growing form of power generation in the world with 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, when the unit is operated at low load, the heat consumption increases by 8% when the unit load rate is 60%, and when the unit load rate is 40%, the heat consumption will increase by 20%. 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.

[0004] Molten salt heat 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. Therefore, using molten salt heat storage technology to solve the problem of insufficient power peak-shaving capacity in thermal power plants dominated by combined cycle units is a very promising technical application method. In the relevant patented technologies, the main technical applications are direct heating of molten salt by high-temperature flue gas for heat storage and peak-shaving, direct heating of molten salt by electric energy for heat storage and peak-shaving, and direct heating of molten salt by high-parameter steam for heat storage and peak-shaving. When high-temperature flue gas and high-parameter steam heat molten salt for heat storage, the gas turbine unit maintains high-efficiency and stable operation, but the operating load of the steam turbine generator unit cannot be reduced to zero, and the heat storage and peak-shaving capacity is limited, which cannot meet the deep power peak-shaving requirements of the power grid. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the defect that when a gas turbine unit operates stably with high efficiency in the prior art, the operating load of the steam turbine generator set cannot be reduced to zero, the heat storage peak shaving capacity is limited, and the deep power peak shaving requirements of the power grid cannot be met. Therefore, a high-temperature molten salt heat storage coupled gas power generation peak shaving system and an operation method are provided.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A high-temperature molten salt heat storage coupled gas power generation peak shaving system includes a gas turbine generator set, a flue gas heat exchange device, a molten salt heat storage heat exchange device, a steam turbine generator set, and a circulating water path;

[0008] The above-mentioned molten salt heat storage heat exchange device includes a low-temperature molten salt storage tank, a low-temperature molten salt pump, a high-temperature molten salt storage tank, a high-temperature molten salt pump, and a molten salt-steam heat exchange mechanism;

[0009] The flue gas outlet of the above-mentioned gas turbine generator set is communicated with the flue gas inlet of the above-mentioned flue gas heat exchange device. The above-mentioned low-temperature molten salt storage tank, the above-mentioned flue gas heat exchange device, the above-mentioned high-temperature molten salt storage tank, and the above-mentioned molten salt-steam heat exchange mechanism are sequentially communicated to form a circulating heat storage heat exchange loop. And the above-mentioned low-temperature molten salt pump is arranged at the molten salt inlet of the above-mentioned flue gas heat exchange device, and the above-mentioned high-temperature molten salt pump is arranged at the molten salt outlet of the above-mentioned high-temperature molten salt storage tank; the above-mentioned steam turbine generator set, the above-mentioned molten salt-steam heat exchange mechanism, and the above-mentioned circulating water path are sequentially communicated to form a steam cycle power generation loop, and the above-mentioned steam turbine generator set is communicated with the steam outlet of the above-mentioned molten salt-steam heat exchange mechanism;

[0010] A low-temperature molten salt bypass pipe is communicated between the molten salt inlet and the molten salt outlet of the above-mentioned low-temperature molten salt storage tank, and a high-temperature molten salt bypass pipe is communicated between the molten salt inlet of the above-mentioned high-temperature molten salt storage tank and the molten salt outlet of the above-mentioned high-temperature molten salt pump.

[0011] Preferably, the above-mentioned molten salt-steam heat exchange mechanism includes a high-pressure superheater, a high-pressure steam drum, a medium-pressure superheater, and a medium-pressure steam drum;

[0012] The molten salt outlets of the above-mentioned high-pressure superheater are communicated with the molten salt inlets of the above-mentioned high-pressure steam drum and the above-mentioned medium-pressure superheater. The molten salt inlets of the above-mentioned medium-pressure steam drum are communicated with the molten salt outlet of the above-mentioned high-pressure steam drum and the molten salt outlet of the above-mentioned medium-pressure superheater. The molten salt inlet of the above-mentioned high-pressure superheater is communicated with the molten salt outlet of the above-mentioned high-temperature molten salt pump. The molten salt outlet of the above-mentioned medium-pressure steam drum is communicated with the molten salt inlet of the above-mentioned low-temperature molten salt storage tank;

[0013] A first water pump is provided at the water inlet of the above-mentioned high-pressure steam drum, a second water pump is provided at the water inlet of the above-mentioned medium-pressure steam drum, the water outlets of the above-mentioned circulating water circuits are all connected to the above-mentioned first water pump and the above-mentioned second water pump, the steam outlet of the above-mentioned high-pressure steam drum is connected to the steam inlet of the above-mentioned high-pressure superheater, the steam outlet of the above-mentioned medium-pressure steam drum is connected to the steam inlet of the above-mentioned medium-pressure superheater, and the steam outlets of the above-mentioned high-pressure superheater and the above-mentioned medium-pressure superheater are respectively connected to the high-pressure steam inlet and the medium-pressure steam inlet of the above-mentioned steam turbine generator set.

[0014] Preferably, the above-mentioned flue gas heat exchange device includes a molten salt waste heat boiler, a molten salt low-temperature heater and a molten salt high-temperature heater. The above-mentioned molten salt low-temperature heater and the above-mentioned molten salt high-temperature heater are arranged in the above-mentioned molten salt waste heat boiler, and the above-mentioned low-temperature molten salt storage tank, the above-mentioned molten salt low-temperature heater, the above-mentioned molten salt high-temperature heater and the above-mentioned high-temperature molten salt storage tank are connected in sequence.

[0015] Preferably, the above-mentioned circulating water circuit includes a condenser, a condensate pump, a third water pump, a deaerator, a fifth water pump and a feed water preheater. The exhaust steam inlet of the above-mentioned condenser is connected to the exhaust steam outlet of the above-mentioned steam turbine generator set. The above-mentioned condenser, the above-mentioned condensate pump, the above-mentioned deaerator, the above-mentioned fifth water pump and the above-mentioned feed water preheater are connected in sequence. The water outlet of the above-mentioned feed water preheater is connected to the water inlet of the above-mentioned molten salt-steam heat exchange mechanism. A make-up water pipe is connected to the water inlet of the above-mentioned deaerator, and the above-mentioned third water pump is arranged on the above-mentioned make-up water pipe.

[0016] Preferably, a low-pressure steam generator is further connected to the flue gas outlet of the above-mentioned flue gas heat exchange device. The water inlet of the above-mentioned low-pressure steam generator is connected to the water outlet of the above-mentioned feed water preheater. The flue gas inlet of the above-mentioned feed water preheater is connected to the flue gas outlet of the above-mentioned low-pressure steam generator. The steam inlet of the above-mentioned deaerator is connected to the steam outlet of the above-mentioned low-pressure steam generator.

[0017] Preferably, a low-pressure steam superheater is further connected to the flue gas outlet of the above-mentioned flue gas heat exchange device. The flue gas outlet of the above-mentioned low-pressure steam superheater is connected to the flue gas inlet of the above-mentioned low-pressure steam generator. The steam outlet of the above-mentioned low-pressure steam generator is connected to the steam inlet of the above-mentioned low-pressure steam superheater. The steam outlet of the above-mentioned low-pressure steam superheater is further connected to an industrial steam user.

[0018] Preferably, the above-mentioned circulating water circuit further includes a hot water storage tank. The water outlet of the above-mentioned hot water storage tank is connected to a fourth water pump. The water inlet of the above-mentioned hot water storage tank is connected to the water outlet of the above-mentioned feed water preheater. The water outlet of the above-mentioned fourth water pump is connected to the water inlets of both the above-mentioned molten salt-steam heat exchange mechanism and the above-mentioned low-pressure steam generator.

[0019] An operation method of a high-temperature molten salt energy storage coupled gas power generation peak shaving system includes:

[0020] When the thermal power plant does not participate in power peak shaving, the above-mentioned gas turbine generator set and the above-mentioned steam turbine generator set both operate at high load to ensure the high-efficiency operation of the thermal power plant. During the operation process, the above-mentioned molten salt heat storage and heat exchange device only participates in the heat exchange process, does not participate in heat storage and heat release, and the molten salt only heats the circulating water into steam by carrying the waste heat of the flue gas;

[0021] When the thermal power plant participates in power peak shaving and needs to reduce the on-grid power load, the above-mentioned gas turbine generator set still operates at high load, and the operation load of the above-mentioned steam turbine generator set is reduced to reduce the on-grid power load. During the operation process, the above-mentioned molten salt heat storage and heat exchange device participates in the heat exchange process and also participates in heat storage. Part of the molten salt carries the waste heat of the flue gas to heat the circulating water into steam, and part of the molten salt with the waste heat of the flue gas is stored;

[0022] When the thermal power plant participates in power peak shaving and needs to increase the on-grid power load, the above-mentioned gas turbine generator set still operates at high load, and the operation load of the above-mentioned steam turbine generator set is increased to increase the on-grid power load. During the operation process, the above-mentioned molten salt heat storage and heat exchange device participates in the heat exchange process and also participates in heat release. Part of the molten salt carries the waste heat of the flue gas to heat the circulating water into steam, and part of the stored molten salt with the waste heat of the flue gas releases heat to heat the circulating water into steam;

[0023] When the thermal power plant participates in power peak shaving and needs to deeply reduce the on-grid power load, the above-mentioned gas turbine generator set still operates at high load, and the operation load of the above-mentioned steam turbine generator set is zero. During the operation process, the above-mentioned molten salt heat storage and heat exchange device does not participate in the heat exchange process and only performs heat storage, and all the molten salt absorbing the waste heat of the flue gas is stored.

[0024] Preferably, when the thermal power plant participates in power peak shaving and needs to reduce the on-grid power load, the high-temperature molten salt from the above-mentioned flue gas heat exchange device is divided into two paths. One path enters the above-mentioned high-temperature molten salt storage tank for heat storage, and the above-mentioned high-temperature molten salt pump does not operate. The other path enters the above-mentioned molten salt-steam heat exchange mechanism through the above-mentioned high-temperature molten salt bypass pipe and exchanges heat with the circulating water therein to be heated into steam, and then enters the above-mentioned steam turbine generator set to generate electricity. Finally, the formed low-temperature molten salt enters the above-mentioned low-temperature molten salt bypass pipe and converges with the low-temperature molten salt output from the above-mentioned low-temperature molten salt storage tank, and then enters the above-mentioned flue gas heat exchange device under the drive of the above-mentioned low-temperature molten salt pump to be heated into high-temperature molten salt for cyclic use, and then enters the above-mentioned high-temperature molten salt storage tank for storage and enters the above-mentioned molten salt-steam heat exchange mechanism for cyclic use respectively.

[0025] Preferably, when the thermal power plant participates in power peak shaving and needs to increase the grid-connected power load, the high-temperature molten salt from the above-mentioned flue gas heat exchange device converges with the high-temperature molten salt from the above-mentioned high-temperature molten salt storage tank under the action of the above-mentioned high-temperature molten salt pump through the above-mentioned high-temperature molten salt bypass pipe and then enters the above-mentioned molten salt-steam heat exchange mechanism together, exchanges heat with the circulating water therein, is heated into steam, then enters the above-mentioned steam turbine generator set for power generation, and finally forms low-temperature molten salt, which is divided into two paths. One path returns to the above-mentioned low-temperature molten salt storage tank for storage, and the other path passes through the above-mentioned low-temperature molten salt bypass pipe and enters the above-mentioned flue gas heat exchange device under the drive of the above-mentioned low-temperature molten salt pump to be reheated into high-temperature molten salt for recycling.

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

[0027] In this system, the flue gas waste heat is used to heat the molten salt, and the molten salt transports the flue gas waste heat to reheat the circulating water into steam, so that the steam turbine generator set generates electricity. The molten salt becomes the carrier of the flue gas waste heat. Through the coordinated operation of the low-temperature molten salt storage tank, the low-temperature molten salt pump, the high-temperature molten salt storage tank, the high-temperature molten salt pump, the molten salt-steam heat exchange mechanism, the low-temperature molten salt bypass pipe and the high-temperature molten salt bypass, the operating load of the steam turbine generator set is adjusted, overcoming the defect that the prior art uses high-parameter steam or part of the high-temperature flue gas to heat the molten salt for heat storage, and the peak shaving ability is limited, and the operating load of the steam turbine unit cannot be reduced to zero while the gas turbine unit operates efficiently. It realizes that the operating load of the steam turbine unit can still be reduced to zero when the gas turbine unit operates at a high load with high efficiency, greatly improves the power peak shaving ability of the thermal power plant, meets the deep power peak shaving requirements of the power grid, and when the thermal power plant participates in power peak shaving and needs to reduce the output power load, the molten salt heat storage device is used to store the high-temperature flue gas waste heat, avoiding choosing to reduce the operating load of the gas turbine unit to meet the power peak shaving requirements, ensuring the high-efficiency operation of the gas turbine unit, and thus relatively improving the energy utilization efficiency of the thermal power plant. Brief Description of the Drawings

[0028] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0029] Figure 1 It is the system block diagram of the embodiment of the present invention.

[0030] Description of the Reference Numerals:

[0031] 1. Gas turbine generator set; 101. Gas turbine compressor; 102. Gas turbine combustor; 103. Gas turbine turbine; 104. First generator; 2. Flue gas heat exchange device; 201. Molten salt waste heat boiler; 202. Molten salt low-temperature heater; 203. Molten salt high-temperature heater; 3. Low-temperature molten salt storage tank; 4. Low-temperature molten salt pump; 5. High-temperature molten salt storage tank; 6. High-temperature molten salt pump; 7. Molten salt-steam heat exchange mechanism; 71. High-pressure superheater; 72. High-pressure steam drum; 73. Medium-pressure superheater; 74. Medium-pressure steam drum; 75. First water pump; 76. Second water pump; 8. Low-temperature molten salt bypass pipe; 9. High-temperature molten salt bypass pipe; 10. Steam turbine generator set; 105. Steam turbine high- and medium-pressure cylinder; 106. Steam turbine low-pressure cylinder; 107. Second generator; 11. Condenser; 12. Condensate pump; 13. Third water pump; 14. Deaerator; 15. Feed water preheater; 16. Make-up water pipe; 17. Condensate pipe; 18. Low-pressure steam generator; 19. Low-pressure steam superheater; 20. Industrial steam user; 21. Hot water storage tank; 22. Fourth water pump; 23. Fifth water pump; 24. First valve; 25. Second valve; 26. Third valve; 27. Fourth valve; 28. Fifth valve; 29. Sixth valve; 30. Seventh valve; 31. Eighth valve; 32. Ninth valve; 33. Tenth valve; 34. Eleventh valve; 35. Twelfth valve; 36. Thirteenth valve; 37. Fourteenth valve; 38. Fifteenth valve; 39. Sixteenth valve; 40. Seventeenth valve; 41. Eighteenth valve; 42. Nineteenth valve; 43. High-pressure steam inlet pipe; 44. Medium-pressure steam inlet pipe. Detailed implementation manners

[0032] 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.

[0033] 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.

[0034] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, 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 communication 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 situations.

[0035] As Figure 1 shown, an embodiment of the present invention provides a high-temperature molten salt energy storage coupled gas power generation peak shaving system, which includes a gas turbine generator set 1, a flue gas heat exchange device 2, a molten salt energy storage heat exchange device, a steam turbine generator set 10, and a circulating water path; the gas turbine generator set 1 includes a gas turbine compressor 101, a gas turbine combustion chamber 102, a gas turbine turbine 103, and a first generator 104. The exhaust port of the gas turbine compressor 101 is connected to the intake port of the gas turbine combustion chamber 102, the exhaust port of the gas turbine combustion chamber 102 is connected to the intake port of the gas turbine turbine 103, the exhaust port of the gas turbine turbine 103 is connected to the flue gas inlet of the molten salt waste heat boiler 201, the gas turbine turbine 103 drives the first generator 104 to generate electricity, and the gas turbine turbine 103 is coaxially connected to the gas turbine compressor 101; the molten salt energy storage heat exchange device includes a low-temperature molten salt storage tank 3, a low-temperature molten salt pump 4, a high-temperature molten salt storage tank 5, a high-temperature molten salt pump 6, and a molten salt-steam heat exchange mechanism 7; the flue gas heat exchange device 2 includes a molten salt waste heat boiler 201, a molten salt low-temperature heater 202, and a molten salt high-temperature heater 203. The molten salt low-temperature heater 202 and the molten salt high-temperature heater 203 are sequentially installed in the molten salt waste heat boiler 201 along the flue gas flow direction, and the low-temperature molten salt storage tank 3, the molten salt low-temperature heater 202, the molten salt high-temperature heater 203, and the high-temperature molten salt storage tank 5 are sequentially connected.

[0036] Specifically, the flue gas outlet of the gas turbine turbine 103 is connected to the flue gas inlet of the flue gas heat exchange device 2. The low-temperature molten salt storage tank 3, the flue gas heat exchange device 2, the high-temperature molten salt storage tank 5, and the molten salt-steam heat exchange mechanism 7 are sequentially connected to form a circulating heat storage and heat exchange loop. Specifically, the molten salt outlet of the low-temperature molten salt storage tank 3 is connected to a first pipe, and a first valve 24 is provided on the first pipe. A second pipe is connected between the first pipe and the molten salt low-temperature heater 202. The low-temperature molten salt pump 4 is provided at the molten salt inlet of the molten salt low-temperature heater 202 and the low-temperature molten salt pump 4 is provided on the second pipe. The molten salt low-temperature heater 202 is connected to the molten salt high-temperature heater 203. The molten salt outlet of the molten salt high-temperature heater 203 is connected to a third pipe. The molten salt inlet of the high-temperature molten salt storage tank 5 is connected to a fourth pipe, and a second valve 25 is connected to the fourth pipe. The third pipe and the fourth pipe are connected. The molten salt outlet of the high-temperature molten salt storage tank 5 is connected to a fifth pipe, and a third valve 26 is connected to the fifth pipe and the high-temperature molten salt pump 6 is located on the fifth pipe. A high-temperature molten salt bypass pipe 9 is connected between the third pipe and the fifth pipe, and a fourth valve 27 is connected to the high-temperature molten salt bypass pipe 9. The fifth pipe is connected to the high-temperature molten salt inlet of the molten salt-steam heat exchange mechanism 7. The low-temperature molten salt outlet of the molten salt-steam heat exchange mechanism 7 is connected to the molten salt inlet of the low-temperature molten salt storage tank 3 by a sixth pipe, and a fifth valve 28 is connected to the sixth pipe. A low-temperature molten salt bypass pipe 8 is connected between the sixth pipe and the first pipe, and a sixth valve 29 is connected to the low-temperature molten salt bypass pipe 8. When the circulating heat storage and heat exchange loop is in use, four closed loops can be formed in the system according to the usage conditions as follows. Loop 1: The fourth valve 27, the sixth valve 29, and the low-temperature molten salt pump 4 are opened. The molten salt low-temperature heater 202, the molten salt high-temperature heater 203, the high-temperature molten salt bypass pipe 9, the molten salt-steam heat exchange mechanism 7, and the low-temperature molten salt bypass pipe 8 form a closed loop, and the low-temperature molten salt storage tank 3 and the high-temperature molten salt storage tank 5 are not involved in the use. In this loop, the molten salt heat storage and heat exchange device only participates in the heat exchange process, does not participate in heat storage and heat release, and only heats the circulating water to steam by carrying the waste heat of the flue gas. Loop 2: The first valve 24, the second valve 25, the fourth valve 27, the sixth valve 29, and the low-temperature molten salt pump 4 are opened. The molten salt low-temperature heater 202, the molten salt high-temperature heater 203, the high-temperature molten salt bypass pipe 9, the molten salt-steam heat exchange mechanism 7, and the low-temperature molten salt bypass pipe 8 form a closed loop, and the low-temperature molten salt storage tank 3 and the high-temperature molten salt storage tank 5 are involved in the use. In this loop, the molten salt heat storage and heat exchange device participates in the heat exchange process and also participates in heat storage. A part of the molten salt carries the waste heat of the flue gas to heat the circulating water to steam, and a part of the molten salt with the waste heat of the flue gas enters the high-temperature molten salt storage tank 5 for storage.Circuit Three: The third valve 26, the fourth valve 27, the fifth valve 28, the sixth valve 29, the low-temperature molten salt pump 4, and the high-temperature molten salt pump 6 are opened. The molten salt low-temperature heater 202, the molten salt high-temperature heater 203, the high-temperature molten salt bypass pipe 9, the molten salt-steam heat exchange mechanism 7, and the low-temperature molten salt bypass pipe 8 form a closed loop. The low-temperature molten salt storage tank 3 and the high-temperature molten salt storage tank 5 are involved in the use. In this circuit, the molten salt heat storage and heat exchange device participates in the heat exchange process and also participates in heat release. Part of the molten salt transports the waste heat of the flue gas to heat the circulating water into steam, and part of the high-temperature molten salt stored in the high-temperature molten salt storage tank 5 is transported out through the high-temperature molten salt pump 6 for heat release, which is used to heat the circulating water into steam to supplement the heat in the system; Circuit Four: The first valve 24, the second valve 25, and the low-temperature molten salt pump 4 are opened. The low-temperature molten salt storage tank 3, the molten salt low-temperature heater 202, the molten salt high-temperature heater 203, and the high-temperature molten salt storage tank 5 form a one-way loop, and the molten salt only participates in the heat storage process.

[0037] Specifically, when the thermal power plant does not participate in power peak shaving, both the gas turbine generator set 1 and the steam turbine generator set 10 operate at high load, and Circuit One operates. When the thermal power plant participates in power peak shaving and needs to reduce the on-grid power load, the above-mentioned gas turbine generator set 1 still operates at high load. When it is necessary to reduce the operating load of the above-mentioned steam turbine generator set 10 to reduce the on-grid power load, Circuit Two operates; when the thermal power plant participates in power peak shaving and needs to increase the on-grid power load, the gas turbine generator set 1 still operates at high load. When it is necessary to increase the operating load of the above-mentioned steam turbine generator set 10 to increase the on-grid power load, Circuit Three operates; when the thermal power plant participates in power peak shaving and needs to deeply reduce the on-grid power load, the gas turbine generator set 1 still operates at high load. When the operating load of the steam turbine generator set 10 needs to be zero, Circuit Four operates; In summary, by heating the molten salt with the waste heat of the flue gas, the molten salt transports the waste heat of the flue gas to heat the circulating water into steam again, so that the steam turbine generator set 10 generates electricity. The molten salt becomes the carrier of the waste heat of the flue gas. By the coordinated operation of the low-temperature molten salt storage tank 3, the low-temperature molten salt pump 4, the high-temperature molten salt storage tank 5, the high-temperature molten salt pump 6, the molten salt-steam heat exchange mechanism 7, the low-temperature molten salt bypass pipe 8, and the high-temperature molten salt bypass, the operating load of the steam turbine generator set 10 is adjusted, overcoming the defect that the prior art uses high-parameter steam or part of the high-temperature flue gas to heat the molten salt for heat storage, and the peak shaving ability is limited because the operating load of the steam turbine generator set 10 cannot be reduced to zero while the gas turbine generator set 1 operates efficiently. It realizes that when the gas turbine generator set 1 operates at high load with high efficiency, the operating load of the steam turbine generator set 10 can still be reduced to zero, greatly improving the power peak shaving ability of the thermal power plant, meeting the requirements of deep power peak shaving of the power grid. Moreover, when the thermal power plant participates in power peak shaving and needs to reduce the output power load, the molten salt heat storage and heat exchange device is used to store the waste heat of the high-temperature flue gas, avoiding choosing to reduce the operating load of the gas turbine generator set 1 to meet the power peak shaving requirements, ensuring the high-efficiency operation of the gas turbine generator set 1, and thus relatively improving the energy utilization efficiency of the thermal power plant.

[0038] The steam turbine generator set 10, the molten salt steam heat exchange mechanism 7, and the circulating water path are connected in sequence to form a steam cycle power generation loop. Specifically, the steam turbine generator set 10 includes a steam turbine high-pressure and intermediate-pressure cylinder 105, a steam turbine low-pressure cylinder 106, and a second generator 107. The steam inlet of the steam turbine high-pressure and intermediate-pressure cylinder 105 is connected to the high-pressure steam inlet of the molten salt steam heat exchange mechanism 7 through a high-pressure steam inlet pipe 43. The steam inlet of the steam turbine low-pressure cylinder 106 is connected to the medium-pressure steam outlet of the molten salt steam heat exchange mechanism 7 through a medium-pressure steam inlet pipe 44. The exhaust port of the steam turbine high-pressure and intermediate-pressure cylinder 105 is connected to the steam inlet of the steam turbine low-pressure cylinder 106 through a medium-low pressure connecting pipe, and a nineteenth valve 42 is installed on the medium-low pressure connecting pipe. The exhaust port of the steam turbine low-pressure cylinder 106 is connected to the exhaust steam inlet of the condenser 11. The steam turbine high-pressure and intermediate-pressure cylinder 105 and the steam turbine low-pressure cylinder 106 are coaxially connected to the second generator 107 and drive the second generator 107 to generate electricity while doing work. The circulating water path includes a condenser 11, a condensate pump 12, a third water pump 13, a deaerator 14, a fifth water pump 23, and a feed water preheater 15. The exhaust steam inlet of the condenser 11 is connected to the exhaust port of the steam turbine generator set 10. The condenser 11 is connected to the condensate pump 12. A condensate pipe 17 is connected between the condensate pump 12 and the deaerator 14. A makeup water pipe 16 is connected to the condensate pipe 17. A third water pump 13 and a seventh valve 30 are connected in sequence on the makeup water pipe 16. An eighth pipe is connected between the water outlet of the deaerator 14 and the water inlet of the feed water preheater 15. The fifth water pump 23 is connected to the eighth pipe. The water outlet of the feed water preheater 15 is connected to a ninth pipe.

[0039] Specifically, the flue gas outlet of the molten salt waste heat boiler 201 is further connected in sequence to a low-pressure steam superheater 19 and a low-pressure steam generator 18. A tenth pipe is connected between the flue gas outlet of the low-pressure steam generator 18 and the flue gas inlet of the feed water preheater 15. An eleventh pipe is connected between the ninth pipe at the water outlet of the feed water preheater 15 and the water inlet of the low-pressure steam generator 18. An eighth valve 31 is provided on the eleventh pipe. A twelfth pipe is connected between the steam outlet of the low-pressure steam generator 18 and the steam inlet of the deaerator 14. A ninth valve 32 is connected to the twelfth pipe. A thirteenth pipe is connected between the steam outlet of the low-pressure steam generator 18 and the steam inlet of the low-pressure steam superheater 19. A tenth valve 33 is connected to the thirteenth pipe. The steam outlet of the low-pressure steam superheater 19 is further connected to an industrial steam user 20. On the one hand, the waste heat of the flue gas is used to heat the steam through the low-pressure steam superheater 19 and the low-pressure steam generator 18 to provide steam for industrial users. On the other hand, the waste heat of the flue gas is used to preheat the circulating water, so that the waste heat of the flue gas is fully utilized.

[0040] Specifically, the circulating water path further includes a hot water storage tank 21. The water outlet of the hot water storage tank 21 is connected to a fourteenth pipe, and the fourteenth pipe is connected to an eleventh valve 34 and a fourth water pump 22. The water outlet of the fourteenth pipe is connected to a ninth pipe. A fifteenth pipe is connected between the water inlet of the hot water storage tank 21 and the ninth pipe at the water outlet of the feed water preheater 15, and the fifteenth pipe is connected to a twelfth valve 35. When the load decreases, the excess hot water can be stored in the hot water storage tank 21. When the load increases, the hot water in the hot water storage tank 21 can be utilized to increase the temperature and flow rate of the circulating water, accelerate the generation of steam, and meet the steam quantity required by the load.

[0041] Specifically, the molten salt steam heat exchange mechanism 7 includes a high-pressure superheater 71, a high-pressure steam drum 72, a medium-pressure superheater 73 and a medium-pressure steam drum 74; the molten salt inlet of the high-pressure superheater 71 is connected to a sixteenth pipe, the fifth pipe and the high-temperature molten salt bypass pipe 9 are both connected to the sixteenth pipe, the molten salt outlet of the high-pressure superheater 71 is connected to a seventeenth pipe, and the seventeenth pipe is connected to the molten salt inlet of the high-pressure steam drum 72 by an eighteenth pipe, and a thirteenth valve 36 is connected to the eighteenth pipe. The molten salt outlet of the high-pressure steam drum 72 is connected to a nineteenth pipe, and a fourteenth valve 37 is connected to the nineteenth pipe. The seventeenth pipe is connected to the molten salt inlet of the medium-pressure superheater 73 by a twentieth pipe, and a fifteenth valve 38 is connected to the twentieth pipe. The molten salt outlet of the medium-pressure superheater 73 is connected to a twenty-first pipe, and the twelfth pipe is connected to a sixteenth valve 39. The molten salt inlet of the medium-pressure steam drum 74 is connected to a twenty-second pipe, and the nineteenth pipe and the twenty-first pipe are both connected to the twenty-second pipe. The molten salt outlet of the medium-pressure steam drum 74 is connected to the molten salt inlet of the low-temperature molten salt storage tank 3 through a sixth pipe; the water outlet of the feed water preheater 15 is connected to a ninth pipe, and a twenty-third pipe is connected between the water inlet of the high-pressure steam drum 72 and the ninth pipe. The twenty-third pipe is sequentially connected to a first water pump 75 and a seventeenth valve 40. The high-pressure steam drum 72 heats the water therein into saturated steam. The steam outlet of the high-pressure steam drum 72 is connected to the steam inlet of the high-pressure superheater 71 by a twenty-fourth pipe, and the steam outlet of the high-pressure superheater 71 is connected to the steam inlet of the high-pressure cylinder 105 of the steam turbine by a high-pressure steam inlet pipe 43; the water inlet of the medium-pressure steam drum 74 is connected to a twenty-fifth pipe between the ninth pipe, and the twenty-fifth pipe is sequentially connected to a second water pump 76 and an eighteenth valve 41. The medium-pressure steam drum 74 heats the water therein into saturated steam. The steam outlet of the medium-pressure steam drum 74 is connected to the steam inlet of the medium-pressure superheater 73 by a twenty-sixth pipe, and the steam outlet of the medium-pressure superheater 73 is connected to the steam inlet of the low-pressure cylinder 106 of the steam turbine by a medium-pressure steam inlet pipe 44; thus, the molten salt enters the high-pressure steam drum 72 and the medium-pressure superheater 73 from the high-pressure superheater 71, then converges into the medium-pressure steam drum 74, and after three heat exchanges, the circulating water is heated into high-pressure steam and medium-pressure steam, enabling the molten salt to fully exchange heat with water or steam. The high-pressure steam comes out of the high-pressure superheater 71 and enters the high-pressure cylinder 105 of the steam turbine through the high-pressure steam inlet pipe 43. The medium-pressure steam enters the low-pressure cylinder 106 of the steam turbine from the medium-pressure superheater 73 through the medium-pressure steam inlet pipe 44, jointly driving the second generator 107 to generate electricity; by reasonably setting the molten salt circulation pipeline and the steam circulation pipeline between the high-pressure superheater 71, the high-pressure steam drum 72, the medium-pressure superheater 73 and the medium-pressure steam drum 74, the cascade high-efficiency utilization of the heat of the high-temperature molten salt is realized, the heat exchange temperature difference is greatly reduced, the irreversible loss is largely reduced, and the output of high-quality steam is increased, greatly enhancing the work capacity of the steam turbine.

[0042] In summary, an operation method of a high-temperature molten salt energy storage coupled gas power generation peak shaving system includes:

[0043] When the thermal power plant does not participate in power peak shaving, both the gas turbine generator set 1 and the steam turbine generator set 10 operate at high load to ensure the high-efficiency operation of the thermal power plant. The high-temperature molten salt storage tank 5 does not store or release heat, but only exchanges heat. At this time: The high-temperature flue gas from the gas turbine turbine 103 heats the molten salt and is all used to heat the feed water to produce steam, and then enters the steam turbine generator set 10 to do work respectively, that is, the first operation loop. The fourth valve 27, the sixth valve 29, and the low-temperature molten salt pump 4 are opened. The molten salt low-temperature heater 202, the molten salt high-temperature heater 203, the high-temperature molten salt bypass pipe 9, the molten salt-steam heat exchange mechanism 7, and the low-temperature molten salt bypass pipe 8 form a closed loop. The low-temperature molten salt storage tank 3 and the high-temperature molten salt storage tank 5 are not involved in use. Specifically, the thirteenth valve 36, the fourteenth valve 37, the fifteenth valve 38, and the sixteenth valve 39 are opened simultaneously. The high-temperature molten salt from the molten salt high-temperature heater 203 directly enters the high-pressure superheater 71 for the first-stage cooling, and then is divided into two paths to enter the high-pressure steam drum 72 and the intermediate-pressure superheater 73 respectively for the second-stage cooling. The high-temperature molten salt after being cooled by the high-pressure steam drum 72 and the intermediate-pressure superheater 73 converges and then enters the intermediate-pressure steam drum 74 for the third-stage cooling, and finally forms low-temperature molten salt and returns to the molten salt waste heat boiler 201. It is heated by the molten salt low-temperature heater 202 and the molten salt high-temperature heater 203 in turn to form high-temperature molten salt, and then returns to the high-pressure superheater 71, and the molten salt heat exchange is carried out in turn.

[0044] The seventeenth valve 40 and the eighteenth valve 41 are opened simultaneously. The high-temperature feed water from the feed water preheater 15 is transported to the high-pressure steam drum 72 by the first water pump 75 and heated to form high-pressure saturated steam. The high-pressure saturated steam then enters the high-pressure superheater 71 and is further heated to form high-pressure superheated steam. Then the high-pressure superheated steam enters the intermediate-high pressure cylinder 105 and the low-pressure cylinder 106 of the steam turbine in turn through the high-pressure steam inlet pipe 43 to do work, driving the second generator 107 to generate electricity. At the same time, the high-temperature feed water from the feed water preheater 15 is transported to the intermediate-pressure steam drum 74 by the second water pump 76 and heated to form intermediate-pressure saturated steam. The intermediate-pressure saturated steam then enters the intermediate-pressure superheater 73 and is further heated to form intermediate-pressure superheated steam. Then the intermediate-pressure superheated steam enters the low-pressure cylinder 106 of the steam turbine through the intermediate-pressure steam inlet pipe 44 to do work, driving the second generator 107 to generate electricity. The exhaust steam discharged after the steam turbine generator set 10 does work enters the condenser 11 and condenses into condensate, which is then transported to the deaerator 14 by the condensate pump 12 for heating, and then transported to the feed water preheater 15 by the fifth water pump 23 and further heated by the flue gas waste heat from the low-pressure steam generator 18 to form high-temperature feed water. The seventh valve 30 is opened simultaneously, and the make-up water pipe 16 is used for water replenishment.

[0045] While opening the eighth valve 31, the ninth valve 32, and the tenth valve 33 simultaneously, the high-temperature feed water from the feed water preheater 15 is also transported to the low-pressure steam generator 18, where it is further heated by the waste heat of the flue gas from the low-pressure steam superheater 19 to form low-pressure saturated steam. Then, it is divided into two paths and enters the deaerator 14 and the low-pressure steam superheater 19 respectively. The low-pressure saturated steam enters the deaerator 14 to heat the condensate from the condenser 11 and the make-up water from the make-up water pipe 16. After the low-pressure saturated steam enters the low-pressure steam superheater 19, it is further heated by the waste heat of the flue gas from the molten salt waste heat boiler 201 to form low-pressure superheated steam, and then transported to the industrial steam user 20 for external heat supply. At the same time, the third water pump 13 is used to supply water to the deaerator 14 to supplement the feed water required for heating the industrial steam user 20.

[0046] When the thermal power plant participates in power peak shaving and needs to reduce the on-grid power load, the gas turbine unit still operates at a high load, and the operating load of the steam turbine generator set 10 is reduced to reduce the on-grid power load. The high-temperature molten salt storage tank 5 stores heat and exchanges heat, resulting in the excess high-temperature molten salt output by the molten salt waste heat boiler 201 being stored by the high-temperature molten salt storage tank 5. At this time: that is, the operating loop two, the first valve 24, the second valve 25, the fourth valve 27, the sixth valve 29, and the low-temperature molten salt pump 4 are opened, and the molten salt low-temperature heater 202, the molten salt high-temperature heater 203, the high-temperature molten salt bypass pipe 9, the molten salt-steam heat exchange mechanism 7, and the low-temperature molten salt bypass pipe 8 form a closed loop, and the low-temperature molten salt storage tank 3 and the high-temperature molten salt storage tank 5 participate in the use. Specifically, while opening the thirteenth valve 36, the fourteenth valve 37, the fifteenth valve 38, and the sixteenth valve 39, the high-temperature molten salt from the molten salt high-temperature heater 203 is divided into two paths. One path enters the high-temperature molten salt storage tank 5 for heat storage, and the amount entering the high-temperature molten salt storage tank 5 can be controlled to reduce the amount of high-temperature molten salt transported to the molten salt-steam heat exchange mechanism 7, thereby further reducing the amount of superheated steam transported from the molten salt-steam heat exchange mechanism 7 to the steam turbine generator set 10, further reducing the operating load of the steam turbine generator set 10, and thus enabling deeper peak shaving. The other path enters the high-pressure superheater 71 for the first-stage temperature reduction, and then is divided into two paths and enters the high-pressure steam drum 72 and the medium-pressure superheater 73 respectively for the second-stage temperature reduction. After the high-temperature molten salt is cooled by the high-pressure steam drum 72 and the medium-pressure superheater 73, it converges and then enters the medium-pressure steam drum 74 for the third-stage temperature reduction, and finally forms low-temperature molten salt, which converges with the low-temperature molten salt output from the low-temperature molten salt storage tank 3 and then returns to the molten salt waste heat boiler 201, and is heated by the molten salt low-temperature heater 202 and the molten salt high-temperature heater 203 in turn to form high-temperature molten salt, and circulates reciprocally. All the excess high-temperature molten salt enters the high-temperature molten salt storage tank 5 for storage.

[0047] Open the seventeenth valve 40 and the eighteenth valve 41 simultaneously. The high-temperature feed water from the feed water preheater 15 is conveyed by the first water pump 75 to the high-pressure steam drum 72, where it is heated to form high-pressure saturated steam. The high-pressure saturated steam then enters the high-pressure superheater 71 and is further heated to form high-pressure superheated steam. Then, the high-pressure superheated steam enters the high-pressure and intermediate-pressure cylinders 105 and the low-pressure cylinder 106 of the steam turbine in sequence through the high-pressure steam inlet pipe 43 to perform work, driving the second generator 107 to generate electricity. At the same time, the high-temperature feed water from the feed water preheater 15 is conveyed by the second water pump 76 to the intermediate-pressure steam drum 74, where it is heated to form intermediate-pressure saturated steam. The intermediate-pressure saturated steam then enters the intermediate-pressure superheater 73 and is further heated to form intermediate-pressure superheated steam. Then, the intermediate-pressure superheated steam enters the low-pressure cylinder 106 of the steam turbine through the intermediate-pressure steam inlet pipe 44 to perform work, driving the second generator 107 to generate electricity. At this time, both the flow rate of the high-pressure superheated steam and the flow rate of the low-pressure superheated steam entering the steam turbine generator set 10 decrease, thereby reducing the operating load of the steam turbine generator set 10. The exhaust steam discharged after performing work by the steam turbine generator set 10 enters the condenser 11 and condenses into condensate, which is then conveyed by the condensate pump 12 to the deaerator 14 for heating, and then conveyed by the fifth water pump 23 to the feed water preheater 15, where it is further heated by the flue gas waste heat from the low-pressure steam generator 18 to form high-temperature feed water.

[0048] Specifically, when the steam turbine generator set 10 reduces its operating load and the required amount of steam decreases, resulting in an excess amount of feed water, which is greater than the amount of feed water required for heating the industrial steam user 20, open the twelfth valve 35, and use the hot water storage tank 21 to store the high-temperature feed water output by the feed water preheater 15 in excess; when the steam turbine generator set 10 reduces its operating load and the required amount of steam decreases, resulting in an excess amount of feed water, which is less than the amount of feed water required for heating the industrial steam user 20, open the fourth water pump 22 and the eleventh valve 34, and / or open the seventh valve 30, and use the hot water storage tank 21 and / or the make-up water pipe 16 to supplement the lacking amount of feed water.

[0049] Open the eighth valve 31, the ninth valve 32, and the tenth valve 33 simultaneously. The high-temperature feed water from the feed water preheater 15 is also conveyed to the low-pressure steam generator 18, where it is further heated by the flue gas waste heat from the low-pressure steam superheater 19 to form low-pressure saturated steam. Then, it is divided into two paths and enters the deaerator 14 and the low-pressure steam superheater 19 respectively. The low-pressure saturated steam enters the deaerator 14 to heat the condensate from the condenser 11 and the make-up water from the make-up water pipe 16. The low-pressure saturated steam enters the low-pressure steam superheater 19 and is further heated by the flue gas waste heat from the molten salt type waste heat boiler 201 to form low-pressure superheated steam, which is then conveyed to the industrial steam user 20 for external heating. At the same time, use the third water pump 13 to make up water for the deaerator 14 to supplement the amount of feed water required for heating the industrial steam user 20.

[0050] When the thermal power plant participates in power peak shaving and needs to increase the grid-connected power load, both the gas turbine unit and the steam turbine generator set 10 operate at high load, and the steam turbine generator set 10 continuously increases its operating load by releasing heat through the molten salt thermal energy storage device, thereby increasing the grid-connected power load. At this time, the molten salt in the high-temperature molten salt storage tank 5 releases heat and also exchanges heat. At this time: In operation loop three, the third valve 26, the fourth valve 27, the fifth valve 28, the sixth valve 29, the low-temperature molten salt pump 4, and the high-temperature molten salt pump 6 are opened, and the molten salt low-temperature heater 202, the molten salt high-temperature heater 203, the high-temperature molten salt bypass pipe 9, the molten salt-steam heat exchange mechanism 7, and the low-temperature molten salt bypass pipe 8 form a closed loop. The low-temperature molten salt storage tank 3 and the high-temperature molten salt storage tank 5 are involved in the use. Specifically, the thirteenth valve 36, the fourteenth valve 37, the fifteenth valve 38, and the sixteenth valve 39 are opened simultaneously. The high-temperature molten salt from the molten salt high-temperature heater 203 and the high-temperature molten salt from the high-temperature molten salt storage tank 5 converge and then enter the molten salt-steam heat exchange mechanism 7. By releasing heat, the amount of high-temperature molten salt transported to the molten salt-steam heat exchange mechanism 7 is increased, thereby increasing the amount of superheated steam transported from the molten salt-steam heat exchange mechanism 7 to the steam turbine generator set 10, to further increase the operating load of the steam turbine generator set 10. The high-temperature molten salt cooled by the high-pressure superheater 71 is divided into two paths and enters the high-pressure steam drum 72 and the intermediate-pressure superheater 73 respectively for the second-stage cooling. The high-temperature molten salt cooled by the high-pressure steam drum 72 and the intermediate-pressure superheater 73 converges and then enters the intermediate-pressure steam drum 74 for the third-stage cooling. Finally, the low-temperature molten salt is divided into two paths. One path returns to the low-temperature molten salt storage tank 3 for storage, and the other path returns to the molten salt waste heat boiler 201. After being heated by the molten salt low-temperature heater 202 and the molten salt high-temperature heater 203 in sequence, it forms high-temperature molten salt, converges with the high-temperature molten salt output from the high-temperature molten salt storage tank 5, and then returns to the high-pressure superheater 71.

[0051] Open the seventeenth valve 40 and the eighteenth valve 41 simultaneously. The high-temperature feed water from the feed water preheater 15 is transported by the first water pump 75 to the high-pressure steam drum 72, where it is heated to form high-pressure saturated steam. The high-pressure saturated steam then enters the high-pressure superheater 71 and is further heated to form high-pressure superheated steam. Then, the high-pressure superheated steam enters the intermediate-pressure cylinder 105 and the low-pressure cylinder 106 of the steam turbine in sequence through the high-pressure steam inlet pipe 43 to perform work, driving the second generator 107 to generate electricity. At the same time, the high-temperature feed water from the feed water preheater 15 is transported by the second water pump 76 to the intermediate-pressure steam drum 74, where it is heated to form intermediate-pressure saturated steam. The intermediate-pressure saturated steam then enters the intermediate-pressure superheater 73 and is further heated to form intermediate-pressure superheated steam. Then, the intermediate-pressure superheated steam enters the low-pressure cylinder 106 of the steam turbine through the intermediate-pressure steam inlet pipe 44 to perform work, driving the second generator 107 to generate electricity. At this time, both the flow rate of the high-pressure superheated steam and the flow rate of the low-pressure superheated steam entering the steam turbine generator set 10 increase, thereby increasing the operating load of the steam turbine generator set 10. The exhaust steam discharged after performing work by the steam turbine generator set 10 enters the condenser 11 and condenses into condensate, which is then transported to the deaerator 14 by the condensate pump 12 for heating, and then transported to the feed water preheater 15 by the fifth water pump 23 and further heated by the flue gas waste heat from the low-pressure steam generator 18 to form high-temperature feed water. When the circulating water volume is insufficient, open the seventh valve 30 and the make-up water pipe 16 for water replenishment.

[0052] Specifically, open the fourth water pump 22 and the eleventh valve 34, and / or open the seventh valve 30, and use the hot water storage tank 21 and / or the make-up water pipe 16 to supplement the water volume required for heating the industrial steam user 20 and the water volume required due to the increase in the steam demand caused by the increase in the operating load of the steam turbine generator set 10.

[0053] Open the eighth valve 31, the ninth valve 32, and the tenth valve 33 simultaneously. The high-temperature feed water from the feed water preheater 15 is also transported to the low-pressure steam generator 18 and is further heated by the flue gas waste heat from the low-pressure steam superheater 19 to form low-pressure saturated steam, which then divides into two paths and enters the deaerator 14 and the low-pressure steam superheater 19 respectively. The low-pressure saturated steam enters the deaerator 14 to heat the condensate from the condenser 11 and the make-up water from the make-up water pipe 16. After the low-pressure saturated steam enters the low-pressure steam superheater 19, it is further heated by the flue gas waste heat from the molten salt type waste heat boiler 201 to form low-pressure superheated steam, which is then transported to the industrial steam user 20 for external heating. At the same time, use the third water pump 13 to replenish water to the deaerator 14 to supplement the water volume required for heating the industrial steam user 20.

[0054] There is also a special case. When the thermal power plant participates in power peak shaving and needs to deeply reduce the on-grid power load, the gas turbine generator set 1 still operates at a high load, and the operating load of the steam turbine generator set 10 is zero. During the operation, the molten salt thermal energy storage heat exchange device does not participate in the heat exchange process, but only stores heat, and all the molten salt that absorbs the waste heat of the flue gas is stored; specifically, for operating loop four, the first valve 24, the second valve 25, and the low-temperature molten salt pump 4 are opened, and the low-temperature molten salt storage tank 3, the molten salt low-temperature heater 202, the molten salt high-temperature heater 203, and the high-temperature molten salt storage tank 5 form a one-way loop. The molten salt only participates in the heat storage process, the steam turbine generator set 10 does not operate, the feedwater preheater 15, the low-pressure steam generator 18, and the low-pressure steam superheater 19 operate, and still supply steam to the industrial steam user 20.

[0055] The above-mentioned 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-substantial changes and substitutions made by those skilled in the art based on the present invention belong to the scope of protection required by the present invention.

Claims

1. A high-temperature molten salt energy storage coupled gas power generation peak shaving system, characterized in that, It includes a gas turbine generator set, a flue gas heat exchange device, a molten salt heat storage heat exchange device, a steam turbine generator set and a circulating water circuit; The molten salt heat storage heat exchange device includes a low-temperature molten salt storage tank, a low-temperature molten salt pump, a high-temperature molten salt storage tank, a high-temperature molten salt pump and a molten salt-steam heat exchange mechanism; The flue gas outlet of the gas turbine generator set is communicated with the flue gas inlet of the flue gas heat exchange device. The low-temperature molten salt storage tank, the flue gas heat exchange device, the high-temperature molten salt storage tank and the molten salt-steam heat exchange mechanism are sequentially communicated to form a circulating heat storage heat exchange loop. The low-temperature molten salt pump is arranged at the molten salt inlet of the flue gas heat exchange device, and the high-temperature molten salt pump is arranged at the molten salt outlet of the high-temperature molten salt storage tank. The steam turbine generator set, the molten salt-steam heat exchange mechanism and the circulating water circuit are sequentially communicated to form a steam cycle power generation loop, and the steam turbine generator set is communicated with the steam outlet of the molten salt-steam heat exchange mechanism; A low-temperature molten salt bypass pipe is communicated between the molten salt inlet and the molten salt outlet of the low-temperature molten salt storage tank, and a high-temperature molten salt bypass pipe is communicated between the molten salt inlet of the high-temperature molten salt storage tank and the molten salt outlet of the high-temperature molten salt pump; When the thermal power plant does not participate in power peak regulation, both the gas turbine generator set and the steam turbine generator set operate at high load. During operation, the molten salt heat storage heat exchange device only participates in the heat exchange process, does not participate in heat storage and heat release, the high-temperature molten salt storage tank and the low-temperature molten salt storage tank are not used, and the molten salt transfers the flue gas waste heat and passes through the high-temperature molten salt bypass pipe to the molten salt-steam heat exchange mechanism to heat the circulating water into steam; When the thermal power plant participates in power peak regulation and needs to reduce the on-grid power load, the gas turbine generator set still operates at high load, and the operation load of the steam turbine generator set is reduced to reduce the on-grid power load. During operation, the molten salt heat storage heat exchange device participates in the heat exchange process and also participates in heat storage, does not release heat. Part of the molten salt transfers the flue gas waste heat and passes through the high-temperature molten salt bypass pipe to the molten salt-steam heat exchange mechanism to heat the circulating water into steam, and part of the molten salt with flue gas waste heat is stored in the high-temperature molten salt storage tank; When the thermal power plant participates in power peak regulation and needs to increase the on-grid power load, the gas turbine generator set still operates at high load, and the operation load of the steam turbine generator set is increased to increase the on-grid power load. During operation, the molten salt heat storage heat exchange device participates in the heat exchange process and also participates in heat release, does not store heat. Part of the molten salt transfers the flue gas waste heat and passes through the high-temperature molten salt bypass pipe to the molten salt-steam heat exchange mechanism to heat the circulating water into steam, and part of the molten salt stored with flue gas waste heat is output from the high-temperature molten salt storage tank and enters the molten salt-steam heat exchange mechanism to release heat and heat the circulating water into steam; When the thermal power plant participates in power peak regulation and needs to deeply reduce the on-grid power load, the gas turbine generator set still operates at high load, and the operation load of the steam turbine generator set is zero. During operation, the molten salt heat storage heat exchange device does not participate in the heat exchange and heat release processes, only stores heat. The low-temperature molten salt in the low-temperature molten salt storage tank enters the flue gas heat exchange device to form high-temperature molten salt, and then is stored in the high-temperature molten salt storage tank. All the molten salt that absorbs the flue gas waste heat is stored up.

2. The gas power generation peak shaving system according to claim 1, wherein The molten salt steam heat exchange mechanism includes a high-pressure superheater, a high-pressure steam drum, a medium-pressure superheater, and a medium-pressure steam drum; The molten salt outlets of the high-pressure superheater are respectively connected to the molten salt inlets of the high-pressure steam drum and the medium-pressure superheater. The molten salt inlets of the medium-pressure steam drum are respectively connected to the molten salt outlets of the high-pressure steam drum and the medium-pressure superheater. The molten salt inlet of the high-pressure superheater is connected to the molten salt outlet of the high-temperature molten salt pump. The molten salt outlet of the medium-pressure steam drum is connected to the molten salt inlet of the low-temperature molten salt storage tank; A first water pump is provided at the water inlet of the high-pressure steam drum, and a second water pump is provided at the water inlet of the medium-pressure steam drum. The water outlets of the circulating water path are respectively connected to the first water pump and the second water 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 medium-pressure steam drum is connected to the steam inlet of the medium-pressure superheater. The steam outlets of the high-pressure superheater and the medium-pressure superheater are respectively connected to the high-pressure steam inlet and the medium-low pressure steam inlet of the steam turbine generator set.

3. The gas power generation peak shaving system according to claim 1, wherein The flue gas heat exchange device includes a molten salt waste heat boiler, a molten salt low-temperature heater, and a molten salt high-temperature heater. The molten salt low-temperature heater and the molten salt high-temperature heater are arranged in the molten salt waste heat boiler. The low-temperature molten salt storage tank, the molten salt low-temperature heater, the molten salt high-temperature heater, and the high-temperature molten salt storage tank are connected in sequence.

4. The gas power generation peak shaving system according to claim 1, wherein The circulating water path includes a condenser, a condensate pump, a third water pump, a deaerator, a fifth water pump, and a feed water preheater. The exhaust steam inlet of the condenser is connected to the exhaust steam outlet of the steam turbine generator set. The condenser, the condensate pump, the deaerator, the fifth water pump, and the feed water preheater are connected in sequence. The water outlet of the feed water preheater is connected to the water inlet of the molten salt steam heat exchange mechanism. A make-up water pipe is connected to the water inlet of the deaerator, and the third water pump is arranged on the make-up water pipe.

5. The gas power generation peak shaving system according to claim 4, wherein A low-pressure steam generator is further connected to the flue gas outlet of the flue gas heat exchange device. The water inlet of the low-pressure steam generator is connected to the water outlet of the feed water preheater. The flue gas inlet of the feed water preheater is connected to the flue gas outlet of the low-pressure steam generator. The steam inlet of the deaerator is connected to the steam outlet of the low-pressure steam generator.

6. The gas power generation peak shaving system according to claim 5, wherein A low-pressure steam superheater is further connected to the flue gas outlet of the flue gas heat exchange device. The flue gas outlet of the low-pressure steam superheater is connected to the flue gas inlet of the low-pressure steam generator. 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 further connected to an industrial steam user.

7. The gas power generation peak shaving system according to claim 5, wherein, The circulating water path further includes a hot water storage tank. The water outlet of the hot water storage tank is connected to a fourth water pump. The water inlet of the hot water storage tank is connected to the water outlet of the feed water preheater. The water outlets of the fourth water pump are respectively connected to the water inlet of the molten salt steam heat exchange mechanism and the water inlet of the low-pressure steam generator.

8. The gas power generation peak shaving system according to claim 1, wherein When the thermal power plant participates in power peak shaving and needs to reduce the on-grid power load, the high-temperature molten salt from the flue gas heat exchange device is divided into two paths. One path enters the high-temperature molten salt storage tank for heat storage, and the high-temperature molten salt pump does not operate. The other path enters the molten salt-steam heat exchange mechanism through the high-temperature molten salt bypass pipe, exchanges heat with the circulating water therein, is heated into steam, then enters the steam turbine generator set for power generation, and finally the formed low-temperature molten salt enters the low-temperature molten salt bypass pipe and converges with the low-temperature molten salt output from the low-temperature molten salt storage tank, and then enters the flue gas heat exchange device under the drive of the low-temperature molten salt pump to be heated into high-temperature molten salt for recycling, and then enters the high-temperature molten salt storage tank for storage and enters the molten salt heat storage and heat exchange device for recycling respectively.

9. The gas power generation peak shaving system according to claim 1, characterized in that, When the thermal power plant participates in power peak shaving and needs to increase the on-grid power load, the high-temperature molten salt from the flue gas heat exchange device converges with the high-temperature molten salt from the high-temperature molten salt storage tank under the action of the high-temperature molten salt pump through the high-temperature molten salt bypass pipe and then enters the molten salt-steam heat exchange mechanism together, exchanges heat with the circulating water therein, is heated into steam, then enters the steam turbine generator set for power generation, and finally the formed low-temperature molten salt is divided into two paths. One path returns to the low-temperature molten salt storage tank for storage, and the other path passes through the low-temperature molten salt bypass pipe and enters the flue gas heat exchange device under the drive of the low-temperature molten salt pump to be reheated into high-temperature molten salt for recycling.

Images