A molten salt thermal energy storage coupled thermal power peak shaving system and method based on multi-parameter heat supply

Abstract

The present invention relates to a molten salt thermal energy storage coupled thermal power peak shaving system and method based on multi-parameter heat supply, including a gas turbine generator set, a molten salt waste heat boiler, a molten salt thermal energy storage device, a molten salt-steam heat exchange mechanism, a steam turbine generator set and a circulating water supply pipeline. The flue gas outlet of the gas turbine generator set is communicated with the flue gas inlet of the molten salt waste heat boiler. The molten salt thermal energy storage device includes a low-temperature molten salt storage tank, a low-temperature molten salt pump, a low-temperature heater, a high-temperature heater, a high-temperature molten salt storage tank and a high-temperature molten salt pump which are connected in sequence. The molten salt-steam heat exchange mechanism includes a high-pressure superheater, a high-pressure evaporator, a medium-pressure superheater, a medium-pressure evaporator, a low-pressure superheater and a low-pressure evaporator. The steam outlet of the medium-pressure superheater is communicated with a high-pressure industrial steam user, and the steam outlet of the low-pressure superheater is communicated with a low-pressure industrial steam user. This system not only has a high peak shaving capacity, but also can meet the steam parameter requirements of different industrial steam users.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal power flexibility, and in particular to a molten salt thermal energy storage coupled thermal power peak shaving system and method based on multi-parameter heat supply. Background Art

[0002] When a combined cycle unit participates in power grid peak shaving, with the fluctuations of power consumption load and new energy power, the operating load fluctuates frequently, resulting in a significant reduction in the efficiency of the combined cycle unit. For example, when the unit operates at low load compared with full load, when the unit load rate is 60%, the heat consumption increases by 8%, and when the unit load rate is 40%, the heat consumption will increase by 20%. Therefore, it is crucial to integrate an energy storage device in the combined cycle system to ensure that the unit can still operate at a relatively high load when participating in power peak shaving, and improve the efficiency and flexibility of the overall system.

[0003] Therefore, using molten salt thermal energy storage technology to solve the problem of insufficient power peak shaving capacity in thermal power plants mainly based on combined cycle units is a very promising technical application method. In related patented technologies, the main technical application methods include directly heating molten salt with high-temperature flue gas for thermal energy storage peak shaving, directly heating molten salt with electric energy for thermal energy storage peak shaving, directly heating molten salt with high-parameter steam for thermal energy storage peak shaving, etc. On the one hand, it directly uses high-temperature molten salt to produce low-parameter steam for users, resulting in irreversible loss of high-grade molten salt thermal energy. On the other hand, it cannot produce steam with corresponding parameters for users, and cannot meet the needs of users. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the defects of irreversible loss of high-grade molten salt thermal energy and inability to meet the steam demand with required parameters of users in the prior art, so as to provide a molten salt thermal energy storage coupled thermal power peak shaving system and method based on multi-parameter heat supply.

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

[0006] A molten salt thermal energy storage coupled thermal power peak shaving system based on multi-parameter heat supply includes a gas turbine generator set, a molten salt waste heat boiler, a molten salt thermal energy storage device, a molten salt steam heat exchange mechanism, a steam turbine generator set, and a circulating water supply pipeline. The flue gas outlet of the gas turbine generator set is communicated with the flue gas inlet of the molten salt waste heat boiler; the molten salt thermal energy storage device includes a low-temperature molten salt storage tank, a low-temperature molten salt pump, a low-temperature heater, a high-temperature heater, a high-temperature molten salt storage tank, and a high-temperature molten salt pump that are connected in sequence. A low-temperature molten salt bypass pipe is connected 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 connected 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.

[0007] The above molten salt steam heat exchange mechanism includes a high-pressure superheater, a high-pressure evaporator, a medium-pressure superheater, a medium-pressure evaporator, a low-pressure superheater, and a low-pressure evaporator. 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 outlets of the high-pressure superheater are respectively connected to the molten salt inlets of the medium-pressure superheater and the high-pressure evaporator. The molten salt outlet of the medium-pressure superheater is connected to the molten salt inlet of the medium-pressure evaporator. The molten salt outlet of the high-pressure evaporator is connected to the molten salt inlet of the low-pressure superheater. The molten salt outlets of the medium-pressure evaporator and the low-pressure superheater are both connected to the molten salt outlet of the low-pressure evaporator. The molten salt outlet of the low-pressure evaporator is connected to the molten salt inlet of the low-temperature molten salt storage tank;

[0008] A first water pump is connected to the water inlet of the high-pressure evaporator, and a second water pump is connected to the water inlet of the medium-pressure evaporator. The water inlets of the first water pump, the second water pump, and the low-pressure evaporator are all connected to the water inlet of the circulating water supply pipeline; the steam outlet of the high-pressure evaporator is connected to the steam inlet of the high-pressure superheater, the steam outlet of the high-pressure superheater is connected to the high-pressure steam inlet of the steam turbine generator set, the steam outlet of the medium-pressure evaporator is connected to the steam inlet of the medium-pressure superheater, the steam outlet of the medium-pressure superheater is connected to a high-pressure industrial steam user, the steam outlet of the low-pressure evaporator is connected to the steam inlet of the low-pressure superheater, the steam outlet of the low-pressure superheater is connected to the medium-low pressure steam inlet of the steam turbine generator set through a low-pressure superheated steam main pipe, and the low-pressure superheated steam main pipe is connected to a low-pressure industrial steam user.

[0009] Preferably, the circulating water supply pipeline includes a condenser, a circulating water pump, a makeup water pump, a circulating water storage tank, a deaerator, a third 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 circulating water pump, the deaerator, the third water pump, and the feed water preheater are connected in sequence. The water outlet of the feed water preheater is connected to the water inlets of the first water pump, the second water pump, and the low-pressure evaporator. A makeup water pipe is connected between the water outlet of the circulating water storage tank and the water inlet of the deaerator, and the makeup water pump is connected to the makeup water pipe.

[0010] Preferably, the water inlet of the circulating water storage tank is further connected to the water outlet of the circulating water pump.

[0011] Preferably, the flue gas outlet of the molten salt waste heat boiler is further connected to a steam generator. The water inlet of the steam generator is connected to the water outlet of the feed water preheater, and the steam outlet of the steam generator is connected to the steam inlet of the deaerator.

[0012] Preferably, the flue gas inlet of the above-mentioned feed water preheater is communicated with the flue gas outlet of the above-mentioned steam generator, and the flue gas outlet of the above-mentioned feed water preheater is communicated with the outside.

[0013] Preferably, the above-mentioned gas turbine generator set includes a gas turbine compressor, a gas turbine combustor, a gas turbine turbine and a first generator. The exhaust port of the above-mentioned gas turbine compressor is communicated with the intake port of the above-mentioned gas turbine combustor. The exhaust port of the above-mentioned gas turbine combustor is communicated with the intake port of the above-mentioned gas turbine turbine. The above-mentioned gas turbine turbine is coaxially connected with the above-mentioned gas turbine compressor. The above-mentioned gas turbine compressor and the above-mentioned gas turbine turbine jointly drive the above-mentioned first generator to generate electricity. The exhaust port of the above-mentioned gas turbine turbine is communicated with the flue gas inlet of the above-mentioned molten salt type waste heat boiler.

[0014] Preferably, the above-mentioned steam turbine generator set includes a steam turbine intermediate and high pressure cylinder, a steam turbine low pressure cylinder and a second generator. The steam inlet of the above-mentioned steam turbine intermediate and high pressure cylinder is communicated with the steam outlet of the above-mentioned high pressure superheater. The exhaust port of the above-mentioned steam turbine intermediate and high pressure cylinder is connected to the steam inlet of the above-mentioned steam turbine low pressure cylinder. The steam inlet of the above-mentioned steam turbine low pressure cylinder is communicated with the above-mentioned low pressure superheated steam main pipe. The above-mentioned steam turbine intermediate and high pressure cylinder and the above-mentioned steam turbine low pressure cylinder are coaxially connected with the above-mentioned second generator. The exhaust port of the above-mentioned steam turbine low pressure cylinder is communicated with the steam inlet of the above-mentioned circulating water supply pipeline.

[0015] A method for a molten salt energy storage coupled thermal power peak shaving system based on multi-parameter heat supply, comprising: when the thermal power plant does not participate in power peak shaving, both the above-mentioned gas turbine generator set and the above-mentioned steam turbine generator set operate at high load to ensure the high-efficiency operation of the thermal power plant. At this time, the above-mentioned molten salt energy storage device does not store or release heat, but only conducts heat exchange. The above-mentioned medium pressure superheater provides high-pressure steam for the above-mentioned high-pressure industrial steam users, and the above-mentioned low pressure superheated steam main pipe provides low-pressure steam for the above-mentioned low-pressure industrial steam users.

[0016] 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 operates at high load, and the on-grid power load is reduced by reducing the operating load of the above-mentioned steam turbine generator set. At this time, the above-mentioned molten salt energy storage device not only stores heat but also participates in heat exchange, thereby reducing the on-grid load. The above-mentioned medium pressure superheater provides high-pressure steam for the above-mentioned high-pressure industrial steam users, and the above-mentioned low pressure superheated steam main pipe provides low-pressure steam for the above-mentioned low-pressure industrial steam users.

[0017] When the thermal power plant participates in power peak shaving and needs to increase the grid-connected power load, the above gas turbine generator sets operate at high load, and the grid-connected power load is increased by increasing the operating load of the above steam turbine generator sets. At this time, the above molten salt heat storage device releases heat and also participates in heat exchange, thereby increasing the grid-connected power load. The above medium-pressure superheater provides high-pressure steam for the above high-pressure industrial steam users, and the above low-pressure superheated steam main pipe provides low-pressure steam for the above low-pressure industrial steam users.

[0018] Preferably, when the thermal power plant participates in power peak shaving and needs to reduce the grid-connected power load, the high-temperature molten salt from the above high-temperature heater enters the above high-temperature molten salt storage tank for heat storage, and the other part enters the above high-pressure superheater through the above high-temperature molten salt bypass pipe for the first-stage cooling, and then is divided into two paths to enter the above high-pressure evaporator and the above medium-pressure superheater respectively for the second-stage cooling. The high-temperature molten salt cooled by the above high-pressure evaporator enters the above low-pressure superheater for the third-stage cooling, and the high-temperature molten salt cooled by the above medium-pressure superheater enters the above medium-pressure evaporator for the third-stage cooling. The high-temperature molten salt cooled by the above low-pressure superheater and the above medium-pressure evaporator converges and then enters the above low-pressure evaporator for the fourth-stage cooling. The finally formed low-temperature molten salt enters the above low-temperature molten salt bypass pipe and converges with the low-temperature molten salt output from the above low-temperature molten salt storage tank, and then is driven by the above low-temperature molten salt pump to return to the above molten salt waste heat boiler again, and is heated successively through the above low-temperature heater and the above high-temperature heater to form high-temperature molten salt, and then enters the above high-temperature molten salt storage tank for storage and enters the above high-pressure superheater for recycling respectively.

[0019] 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 high-temperature heater and the high-temperature molten salt from the above-mentioned high-temperature molten salt storage tank converge and then enter the above-mentioned high-pressure superheater for the first-stage cooling. Thus, heat is released through the above-mentioned molten salt thermal energy storage device to increase the amount of high-temperature molten salt transported to the above-mentioned molten salt-steam heat exchange mechanism, thereby increasing the amount of superheated steam transported from the above-mentioned molten salt-steam heat exchange mechanism to the above-mentioned steam turbine generator set, so as to further increase the operating load of the steam turbine generator set. The high-temperature molten salt after being cooled by the above-mentioned high-pressure superheater is divided into two paths and enters the above-mentioned high-pressure evaporator and the above-mentioned medium-pressure superheater respectively for the second-stage cooling. The high-temperature molten salt after being cooled by the above-mentioned high-pressure evaporator enters the above-mentioned low-pressure superheater for the third-stage cooling. The high-temperature molten salt after being cooled by the above-mentioned medium-pressure superheater enters the above-mentioned medium-pressure evaporator for the third-stage cooling. The high-temperature molten salt after being cooled by the above-mentioned low-pressure superheater and the above-mentioned medium-pressure evaporator converges and then enters the above-mentioned low-pressure evaporator for the fourth-stage cooling. Finally, the low-temperature molten salt is divided into two paths. One path returns to the above-mentioned low-temperature molten salt storage tank for storage, and the other path returns to the above-mentioned molten salt waste heat boiler again through the above-mentioned low-temperature molten salt bypass pipe and driven by the above-mentioned low-temperature molten salt pump, and then is heated by the above-mentioned low-temperature heater and the above-mentioned high-temperature heater to form high-temperature molten salt for recycling.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] A molten salt steam heat exchange mechanism composed of a high-pressure superheater, a high-pressure evaporator, a medium-pressure superheater, a medium-pressure evaporator, a low-pressure superheater and a low-pressure evaporator. By arranging the molten salt circulation pipelines among the high-pressure superheater, the high-pressure evaporator, the medium-pressure superheater, the medium-pressure evaporator, the low-pressure superheater and the low-pressure evaporator, the molten salt is cooled four times before and after, and the energy cascade utilization of the molten salt is sufficient, greatly reducing the heat exchange temperature difference and largely reducing the irreversible loss of the molten salt energy. Moreover, by reasonably arranging the steam circulation pipelines among the high-pressure superheater, the high-pressure evaporator, the medium-pressure superheater, the medium-pressure evaporator, the low-pressure superheater and the low-pressure evaporator, the steam circulation pipelines of the molten salt steam heat exchange mechanism are divided into three paths, which fully exchange heat with the molten salt, and can efficiently generate different-parameter steam based on the cascade matching of energy grades. It can not only meet the steam required for the steam turbine generator set to do work, increase the output of high-quality steam, and greatly improve the power generation capacity of the steam turbine generator set, but also meet the requirements of different industrial steam users for steam parameters, and increase the diversity of external heat supply, which is conducive to expanding the external heat supply market. Moreover, the setting of the molten salt heat storage device overcomes the peak shaving capacity defect of the prior art that using high-parameter steam or part of high-temperature flue gas to heat the molten salt for heat storage cannot reduce the operating load of the steam turbine generator set to zero while the gas turbine generator set operates efficiently. It realizes that when the gas turbine generator set operates at high load with high efficiency, the operating load of the steam turbine generator set can still be reduced to zero, greatly improving the power peak shaving capacity of the thermal power plant and meeting the deep power peak shaving requirements of the power grid. Brief Description of the Drawings

[0022] 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 the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0023] Figure 1 It is the system block diagram of the embodiment of the present invention.

[0024] Description of the Reference Numerals:

[0025] 1. Gas turbine generator set; 101. Gas turbine compressor; 102. Gas turbine combustion chamber; 103. Gas turbine turbine; 104. First generator; 2. Molten salt waste heat boiler; 3. Low-temperature molten salt storage tank; 4. Low-temperature molten salt pump; 5. Low-temperature heater; 6. High-temperature heater; 7. High-temperature molten salt storage tank; 8. High-temperature molten salt pump; 9. Low-temperature molten salt bypass pipe; 10. High-temperature molten salt bypass pipe; 11. Molten salt-steam heat exchange mechanism; 111. High-pressure superheater; 112. High-pressure evaporator; 113. Medium-pressure superheater; 114. Medium-pressure evaporator; 115. Low-pressure superheater; 116. Low-pressure evaporator; 117. First water pump; 118. Second water pump; 12. High-pressure superheated steam main pipe; 13. Low-pressure superheated steam main pipe; 14. Steam turbine generator set; 141. Steam turbine high- and medium-pressure cylinder; 142. Steam turbine low-pressure cylinder; 143. Second generator; 15. Condenser; 16. Circulating water pump; 17. Make-up water pump; 18. Circulating water storage tank; 19. Deaerator; 20. Feed water preheater; 21. Steam generator; 22. Third water pump; 23. Condensate pipe; 24. Make-up water pipe; 25. High-pressure industrial steam supply pipe; 26. High-pressure industrial steam user; 27. Low-pressure industrial steam supply pipe; 28. Low-pressure industrial steam user; 29. First valve; 30. Second valve; 31. Third valve; 32. Fourth valve; 33. Fifth valve; 34. Sixth valve; 35. Seventh valve; 36. Eighth valve; 37. Ninth valve; 38. Tenth valve; 39. Eleventh valve; 40. Twelfth valve; 41. Thirteenth valve; 42. Fourteenth valve; 43. Fifteenth valve; 44. Sixteenth valve; 45. Seventeenth valve; 46. Eighteenth valve; 47. Nineteenth valve; 48. Twentieth valve; 49. Twenty-first valve; 50. Twenty-second valve; 51. Twenty-third valve. Detailed implementation manner

[0026] 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.

[0027] 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 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.

[0028] In the description of the present invention, it should be noted that, unless otherwise clearly specified and defined, the terms "installed", "connected", and "coupled" 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.

[0029] As Figure 1 shown, the present invention provides a molten salt thermal energy storage coupled thermal power peak shaving system based on multi-parameter heat supply, including a gas turbine generator set 1, a molten salt waste heat boiler 2, a molten salt thermal energy storage device, a molten salt steam heat exchange mechanism 11, a steam turbine generator set 14, and a circulating water supply pipeline.

[0030] 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 communicated with the intake port of the gas turbine combustion chamber 102. The exhaust port of the gas turbine combustion chamber 102 is communicated with the intake port of the gas turbine turbine 103. The exhaust port of the gas turbine turbine 103 is communicated with the flue gas inlet of the molten salt waste heat boiler 2. The gas turbine turbine 103 is coaxially connected with the gas turbine compressor 101. The gas turbine compressor 101 and the gas turbine turbine 103 drive the first generator 104 to generate electricity. The flue gas outlet of the gas turbine generator set 1 is communicated with the flue gas inlet of the molten salt waste heat boiler 2 through a flue gas pipeline.

[0031] The steam turbine generator set 14 includes a steam turbine high and intermediate pressure cylinder 141, a steam turbine low pressure cylinder 142, and a second generator 143. The exhaust port of the steam turbine high and intermediate pressure cylinder 141 is connected to the intake port of the steam turbine low pressure cylinder 142 through a high and low pressure connecting pipe, and a twenty-third valve 51 is installed on the high and low pressure connecting pipe. The steam turbine high and intermediate pressure cylinder 141 and the steam turbine low pressure cylinder 142 are coaxially connected with the second generator 143 and simultaneously do work to drive the second generator 143 to generate electricity.

[0032] The molten salt thermal energy storage device includes a low-temperature molten salt storage tank 3, a low-temperature molten salt pump 4, a low-temperature heater 5, a high-temperature heater 6, a high-temperature molten salt storage tank 7, and a high-temperature molten salt pump 8. The molten salt outlet of the low-temperature molten salt storage tank 3 is connected to a first pipe, and a first valve 29 is provided on the first pipe. A second pipe is connected between the first pipe and the low-temperature heater 5. The low-temperature molten salt pump 4 is arranged at the molten salt inlet of the low-temperature heater 5 and the low-temperature molten salt pump 4 is arranged on the second pipe. The low-temperature heater 5 and the high-temperature heater 6 are sequentially installed in the molten salt waste heat boiler 2 along the flue gas flow direction. The low-temperature heater 5 and the high-temperature heater 6 are connected. The molten salt outlet of the high-temperature heater 6 is connected to a third pipe. The molten salt inlet of the high-temperature molten salt storage tank 7 is connected to a fourth pipe, and a second valve 30 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 7 is connected to a fifth pipe, a third valve 31 is connected to the fifth pipe and the high-temperature molten salt pump 8 is located on the fifth pipe. A high-temperature molten salt bypass pipe 10 is connected between the third pipe and the fifth pipe, and a fourth valve 32 is connected to the high-temperature molten salt bypass pipe 10. The fifth pipe is connected to the high-temperature molten salt inlet of the molten salt-steam heat exchange mechanism 11. The low-temperature molten salt outlet of the molten salt-steam heat exchange mechanism 11 is connected to the molten salt inlet of the low-temperature molten salt storage tank 3 by a sixth pipe, and a fifth valve 33 is connected to the sixth pipe. A low-temperature molten salt bypass pipe 9 is connected between the sixth pipe and the first pipe, and a sixth valve 34 is connected to the low-temperature molten salt bypass pipe 9.

[0033] 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 14 operate at high loads to ensure the high-efficiency operation of the thermal power plant. At this time, the fourth valve 32, the sixth valve 34, and the low-temperature molten salt pump 4 are opened, and the low-temperature heater 5, the high-temperature heater 6, the high-temperature molten salt bypass pipe 10, the molten salt-steam heat exchange mechanism 11, and the low-temperature molten salt bypass pipe 9 form a closed loop. The low-temperature molten salt storage tank 3 and the high-temperature molten salt storage tank 7 do not participate in use. In this loop, the molten salt heat storage and heat exchange device only participates in the heat exchange process and does not participate in heat storage and heat release. The waste heat of the flue gas is carried into the molten salt-steam heat exchange mechanism 11 to heat the circulating water into steam; when the thermal power plant participates in power peak shaving and needs to reduce the on-grid power load, the gas turbine generator set 1 operates at a high load, and the on-grid power load is reduced by reducing the operating load of the steam turbine generator set 14. At this time, the first valve 29, the second valve 30, the fourth valve 32, the sixth valve 34, and the low-temperature molten salt pump 4 are opened, and the low-temperature heater 5, the high-temperature heater 6, the high-temperature molten salt bypass pipe 10, the molten salt-steam heat exchange mechanism 11, and the low-temperature molten salt bypass pipe 9 form a closed loop. The low-temperature molten salt storage tank 3 and the high-temperature molten salt storage tank 7 participate in use. In this loop, the molten salt heat storage 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 into the molten salt-steam heat exchange mechanism 11 to heat the circulating water into steam, and a part of the molten salt carrying the waste heat of the flue gas enters the high-temperature molten salt storage tank 7 for storage; 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 operates at a high load, and the on-grid power load is increased by increasing the operating load of the steam turbine generator set 14. At this time, the third valve 31, the fourth valve 32, the fifth valve 33, the sixth valve 34, the low-temperature molten salt pump 4, and the high-temperature molten salt pump 8 are opened, and the low-temperature heater 5, the high-temperature heater 6, the high-temperature molten salt bypass pipe 10, the molten salt-steam heat exchange mechanism 11, and the low-temperature molten salt bypass pipe 9 form a closed loop. The low-temperature molten salt storage tank 3 and the high-temperature molten salt storage tank 7 participate in use. In this loop, the molten salt heat storage device participates in the heat exchange process and also participates in heat release. A part of the molten salt carries the waste heat of the flue gas into the molten salt-steam heat exchange mechanism 11 to heat the circulating water into steam, and a part of the high-temperature molten salt stored in the high-temperature molten salt storage tank 7 is transported out by the high-temperature molten salt pump 8 for heat release, heating the circulating water into steam to supplement the heat in the system. After heat release, the low-temperature molten salt enters the low-temperature molten salt storage tank 3 for storage; moreover, when the first valve 29, the second valve 30, and the low-temperature molten salt pump 4 are opened, the low-temperature molten salt storage tank 3, the low-temperature heater 5, the high-temperature heater 6, and the high-temperature molten salt storage tank 7 form a one-way loop, and the molten salt only participates in the heat storage process. At this time, the steam turbine generator set 14 does not operate, and only the gas turbine generator set 1 operates. At this time, the power grid performs an extremely deep peak shaving;In summary, under the combined operation of the low-temperature molten salt storage tank 3, the low-temperature molten salt pump 4, the low-temperature heater 5, the high-temperature heater 6, the high-temperature molten salt storage tank 7, the high-temperature molten salt pump 8, the low-temperature molten salt bypass pipe 9 and the high-temperature molten salt bypass pipe 10, it can not only meet the peak shaving of the power grid, but also overcome the defect of limited peak shaving ability in the prior art that when using high-parameter steam or partial high-temperature flue gas to heat molten salt for heat storage, the operating load of the steam turbine generator set 14 cannot be reduced to zero while the gas turbine generator set 1 operates efficiently. It can achieve high-efficiency power peak shaving, and the peak shaving ability is higher.

[0034] The molten salt-steam heat exchange mechanism 11 includes a high-pressure superheater 111, a high-pressure evaporator 112, a medium-pressure superheater 113, a medium-pressure evaporator 114, a low-pressure superheater 115 and a low-pressure evaporator 116. The molten salt inlet of the high-pressure superheater 111 is connected to a seventh pipe, and the seventh pipe is connected to the molten salt outlets of the high-temperature molten salt bypass pipe 10 and the high-temperature molten salt pump 8. The molten salt outlet of the high-pressure superheater 111 is connected to an eighth pipe, and the eighth pipe is connected to the molten salt inlet of the medium-pressure superheater 113 through a ninth pipe, and a seventh valve 35 is connected to the ninth pipe. The molten salt outlet of the medium-pressure superheater 113 is connected to the molten salt inlet of the medium-pressure evaporator 114 through a tenth pipe. The molten salt outlet of the medium-pressure evaporator 114 is connected to an eleventh pipe, and an eighth valve 36 is connected to the eleventh pipe. The eighth pipe is also connected to the molten salt inlet of the high-pressure evaporator 112 through a twelfth pipe, and a ninth valve 37 is connected to the twelfth pipe. The molten salt outlet of the high-pressure evaporator 112 is connected to the molten salt inlet of the low-pressure superheater 115 through a thirteenth pipe. The molten salt outlet of the low-pressure superheater 115 is connected to a fourteenth pipe, and a tenth valve 38 is connected to the fourteenth pipe. The molten salt inlet of the low-pressure evaporator 116 is connected to a fifteenth pipe, and the fifteenth pipe is connected to both the eleventh pipe and the fourteenth pipe. The molten salt outlet of the low-pressure evaporator 116 is connected to the sixth pipe. The medium-pressure superheater 113 and the medium-pressure evaporator 114 are connected in parallel with the high-pressure evaporator 112 and the low-pressure superheater 115. In summary, by setting the molten salt circulation pipelines among the high-pressure superheater 111, the high-pressure evaporator 112, the medium-pressure superheater 113, the medium-pressure evaporator 114, the low-pressure superheater 115 and the low-pressure evaporator 116, the molten salt undergoes four temperature drops successively during the circulation process, the energy cascade utilization of the molten salt is sufficient, the heat transfer temperature difference is greatly reduced, and the irreversible loss of the molten salt energy is largely reduced.

[0035] The steam circulation pipeline in the molten salt steam heat exchange mechanism 11 is divided into three paths. The first path generates high-pressure steam and supplies it to the high-pressure and medium-pressure cylinders 141 of the steam turbine. Specifically, a sixteenth pipe is connected between the water inlet of the high-pressure evaporator 112 and the water outlet of the circulating water supply pipeline. A first water pump 117 and an eleventh valve 39 are successively connected to the sixteenth pipe. The steam outlet of the high-pressure evaporator 112 is connected to the steam inlet of the high-pressure superheater 111. A high-pressure superheated steam main pipe 12 is connected between the steam outlet of the high-pressure superheater 111 and the steam inlet of the high-pressure and medium-pressure cylinders 141 of the steam turbine. A twelfth valve 40 is connected to the high-pressure superheated steam main pipe 12. The second path generates medium-pressure superheated steam and supplies it to the high-pressure industrial steam user 26. Specifically, a seventeenth pipe is connected between the water inlet of the medium-pressure evaporator 114 and the water outlet of the circulating water supply pipeline. A thirteenth valve 41 and a second water pump 118 are successively connected to the seventeenth pipe. The steam outlet of the medium-pressure evaporator 114 is connected to the steam inlet of the medium-pressure superheater 113. A high-pressure industrial steam supply pipe 25 is connected to the steam outlet of the medium-pressure superheater 113. A fourteenth valve 42 is connected to the high-pressure industrial steam supply pipe 25. And the outlet of the high-pressure industrial steam supply pipe 25 is connected to the high-pressure industrial steam user 26. The third path generates low-pressure superheated steam and supplies it for use by the low-pressure cylinder 142 of the steam turbine and the low-pressure industrial steam user 28. Specifically, an eighteenth pipe is connected between the water inlet of the low-pressure evaporator 116 and the water outlet of the circulating water supply pipeline. A fifteenth valve 43 is connected to the eighteenth pipe. The steam outlet of the low-pressure evaporator 116 is connected to the steam inlet of the low-pressure superheater 115. A low-pressure superheated steam main pipe 13 is connected between the steam outlet of the low-pressure superheater 115 and the steam inlet of the low-pressure cylinder 142 of the steam turbine. A sixteenth valve 44 is connected to the low-pressure superheated steam main pipe 13 at the steam inlet of the low-pressure cylinder 142 of the steam turbine. And a low-pressure industrial steam supply pipe 27 is connected to the low-pressure superheated steam main pipe 13. A seventeenth valve 45 is connected to the low-pressure industrial steam supply pipe 27. And the outlet of the low-pressure industrial steam supply pipe 27 is connected to the low-pressure industrial steam user 28. To sum up, by reasonably arranging the steam circulation pipeline among the high-pressure superheater 111, high-pressure evaporator 112, medium-pressure superheater 113, medium-pressure evaporator 114, low-pressure superheater 115 and low-pressure evaporator 116, the steam circulation pipeline of the molten salt steam heat exchange mechanism 11 is divided into three paths, which fully exchanges heat with the molten salt and can efficiently generate different-parameter steam based on the cascade matching of energy grades. It can not only meet the steam required for the steam turbine generator set 14 to do work, increase the output of high-quality steam, and greatly improve the power generation capacity of the steam turbine generator set 14, but also meet the steam parameter requirements of different industrial steam users, and increase the diversity of external heat supply, which is conducive to expanding the external heat supply market.

[0036] Specifically, the circulating water supply pipeline includes a condenser 15, a circulating water pump 16, a make-up water pump 17, a circulating water storage tank 18, a deaerator 19, a third water pump 22, and a feed water preheater 20. The exhaust steam inlet of the condenser 15 is connected to the exhaust port of the steam turbine generator set 14. The water outlet of the condenser 15 is connected to the water inlet of the circulating water pump 16. A condensate pipe 23 is connected between the circulating water pump 16 and the deaerator 19. An eighteenth valve 46 is connected to the condensate pipe 23. A nineteenth pipe is connected between the deaerator 19 and the feed water preheater 20. The third water pump 22 is connected to the nineteenth pipe. The water outlet of the feed water preheater 20 is connected to a twentieth pipe, and the twentieth pipe is connected to both the first water pump 117 and the second water pump 118. A make-up water pipe 24 is connected to the condensate pipe 23. The make-up water pipe 24 is connected to the water outlet of the circulating water storage tank 18. The make-up water pump 17 is connected to the make-up water pipe 24. A nineteenth valve 47 is connected to the make-up water pipe 24. The water inlet of the circulating water storage tank 18 is connected to the condensate pipe 23 at the water outlet of the circulating water pump 16 by a twenty-first pipe. A twentieth valve 48 is connected to the twenty-first pipe. The eighteenth valve 46 is located on the condensate pipe 23 in parallel with the circulating water storage tank 18. The circulating water storage tank 18 functions to store and supply water. First, when the steam turbine generator set 14 is operating normally, it is used to supplement the water supply required for heating industrial steam users. Second, when the steam turbine generator set 14 reduces its operating load and the required amount of steam decreases, resulting in excess water supply, and the excess water supply is greater than the water supply required for heating industrial steam users, the excess water is stored in the circulating water storage tank 18. When the steam turbine generator set 14 reduces its operating load and the required amount of steam decreases, resulting in excess water supply, and the excess water supply is less than the water supply required for heating industrial steam users, the circulating water storage tank 18 is used to supplement the missing water supply. Third, when the steam turbine generator set 14 increases its operating load and the required amount of steam increases, the circulating water storage tank 18 is used to supply water to the deaerator 19, supplementing the water supply required for heating industrial steam users and increasing the steam inlet of the steam turbine generator set 14.

[0037] Specifically, the flue gas outlet of the molten salt type waste heat boiler 2 is also connected to a steam generator 21. A twenty-second pipe is connected between the water inlet of the steam generator 21 and the water outlet of the feed water preheater 20. A twenty-first valve 49 is connected to the twenty-second pipe. A twenty-third pipe is connected between the steam outlet of the steam generator 21 and the steam inlet of the deaerator 19. A twenty-second valve 50 is connected to the twenty-third pipe. The flue gas inlet of the feed water preheater 20 is connected to the flue gas outlet of the steam generator 21, and the flue gas outlet of the feed water preheater 20 is connected to the outside, making full use of the flue gas waste heat.

[0038] In summary, a method for a molten salt thermal energy storage coupled thermal power peak shaving system based on multi-parameter heat supply includes: 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 14 operate at high load to ensure the high-efficiency operation of the thermal power plant, that is: the fourth valve 32, the sixth valve 34, and the low-temperature molten salt pump 4 are opened, and the low-temperature heater 5, the high-temperature heater 6, the high-temperature molten salt bypass pipe 10, the molten salt-steam heat exchange mechanism 11, and the low-temperature molten salt bypass pipe 9 form a closed loop, and the low-temperature molten salt storage tank 3 and the high-temperature molten salt storage tank 7 are not used. At the same time, the seventh valve 35, the eighth valve 36, the ninth valve 37, and the tenth valve 38 are opened. The high-temperature molten salt from the high-temperature heater 6 first enters the high-pressure superheater 111 for the first-stage temperature reduction, and then is divided into two paths to enter the high-pressure evaporator 112 and the medium-pressure superheater 113 respectively for the second-stage temperature reduction. The high-temperature molten salt after the temperature reduction by the high-pressure evaporator 112 then enters the low-pressure superheater 115 for the third-stage temperature reduction. The high-temperature molten salt after the temperature reduction by the medium-pressure superheater 113 then enters the medium-pressure evaporator 114 for the third-stage temperature reduction. The high-temperature molten salt after the temperature reduction by the low-pressure superheater 115 and the medium-pressure evaporator 114 converges and then enters the low-pressure evaporator 116 for the fourth-stage temperature reduction, and finally forms low-temperature molten salt and returns to the molten salt waste heat boiler 2 through the low-temperature molten salt bypass pipe 9 under the action of the low-temperature molten salt pump 4, and is heated by passing through the low-temperature heater 5 and the high-temperature heater 6 in sequence to form high-temperature molten salt, and then returns to the high-pressure superheater 111 for recycling.

[0039] Open the eleventh valve 39, the twelfth valve 40, the fifteenth valve 43 and the sixteenth valve 44 simultaneously. The high-temperature feed water from the feed water preheater 20 enters the high-pressure evaporator 112 and the low-pressure evaporator 116 respectively and is heated. The high-pressure saturated steam formed by heating in the high-pressure evaporator 112 enters the high-pressure superheater 111 and is further heated to form high-pressure superheated steam. Then, the high-pressure superheated steam enters the high-pressure and intermediate-pressure cylinder 141 and the low-pressure cylinder 142 of the steam turbine in sequence to do work and drive the second generator 143 to generate electricity. The low-pressure saturated steam formed by heating in the low-pressure evaporator 116 enters the low-pressure superheater 115 and is further heated to form low-pressure superheated steam. Then, the low-pressure superheated steam enters the low-pressure cylinder 142 of the steam turbine to do work and drive the second generator 143 to generate electricity. The exhaust steam discharged after passing through the steam turbine generator set 14 enters the condenser 15 to form condensed water. Open the eighteenth valve 46 simultaneously, and then it is transported by the circulating water pump 16 to the deaerator 19 for heating, and then transported by the third water pump 22 to the feed water preheater 20 to be further heated by the flue gas waste heat from the steam generator 21 to form high-temperature feed water for recycling; Open the thirteenth valve 41, the fourteenth valve 42 and the seventeenth valve 45 simultaneously. The high-temperature feed water from the feed water preheater 20 is also transported to the intermediate-pressure evaporator 114 to be heated to form intermediate-pressure saturated steam, and then enters the intermediate-pressure superheater 113 to be further heated to form intermediate-pressure superheated steam. Finally, the intermediate-pressure superheated steam is transported through the high-pressure industrial steam supply pipe 25 to the high-pressure industrial steam user 26 for external heat supply. The low-pressure superheated steam output from the low-pressure superheater 115 is also transported through the low-pressure industrial steam supply pipe 27 to the low-pressure industrial steam user 28 for external heat supply.

[0040] Open the twenty-first valve 49 and the twenty-second valve 50 simultaneously. The high-temperature feed water from the feed water preheater 20 is also transported to the steam generator 21 and is heated by the flue gas waste heat from the molten salt type waste heat boiler 2 to form saturated steam, and then transported to the deaerator 19 to be used for heating the circulating water in the deaerator 19; Open the nineteenth valve 47 simultaneously, and use the circulating water storage tank 18 to replenish water for the deaerator 19 to supplement the feed water required for heating the high-pressure industrial steam user 26 and the low-pressure industrial steam user 28.

[0041] When the thermal power plant participates in power peak regulation and needs to reduce the on-grid power load, the gas turbine generator set 1 maintains high load operation, and the on-grid power load is reduced by reducing the operating load of the steam turbine generator set 14. At this time, the molten salt heat storage device not only stores heat, but also participates in heat exchange, thereby reducing the on-grid load, that is, the first valve 29, the second valve 30, the fourth valve 32, the sixth valve 34 and the low-temperature molten salt pump 4 are opened, the low-temperature heater 5, the high-temperature heater 6, the high-temperature molten salt bypass pipe 10, the molten salt steam heat exchange mechanism 11 and the low-temperature molten salt bypass pipe 9 form a closed loop, the low-temperature molten salt storage tank 3 and the high-temperature molten salt storage tank 7 are used, and the seventh valve 35, the eighth valve 36, the ninth valve 37 and the tenth valve 38 are opened at the same time. The high-temperature molten salt from the high-temperature heater 6 is first divided into two paths, one of which enters the high-temperature molten salt storage tank 7 for heat storage, thereby reducing the amount of high-temperature molten salt transported to the molten salt steam heat exchange mechanism 11 to reduce the amount of superheated steam transported to the steam turbine generator set 14 by the molten salt steam heat exchange mechanism 11, thereby reducing the steam turbine generator The high-temperature molten salt from the high-pressure superheater 111 is also divided into two paths and enters the high-pressure evaporator 112 and the medium-pressure superheater 113 for the second stage of cooling. The high-temperature molten salt cooled by the high-pressure evaporator 112 enters the low-pressure superheater 115 for the third stage of cooling. The high-temperature molten salt cooled by the medium-pressure superheater 113 enters the medium-pressure evaporator 114 for the third stage of cooling. The high-temperature molten salt after cooling in the device 114 is combined and then enters the low-pressure evaporator 116 for the fourth stage cooling. The finally formed low-temperature molten salt enters the low-temperature molten salt bypass pipe 9 and merges with the low-temperature molten salt output from the low-temperature molten salt storage tank 3. Then, driven by the low-temperature molten salt pump 4, it returns to the molten salt waste heat boiler 2 again, and is heated by the low-temperature heater 5 and the high-temperature heater 6 in turn to form high-temperature molten salt, and then enters the high-temperature molten salt storage tank 7 for storage and enters the high-pressure superheater 111 for recycling.

[0042] The eleventh valve 39, the twelfth valve 40, the fifteenth valve 43 and the sixteenth valve 44 are opened simultaneously. The high-temperature feed water from the feed water preheater 20 enters the high-pressure evaporator 112 and the low-pressure evaporator 116 respectively and is heated. The high-pressure saturated steam formed by heating in the high-pressure evaporator 112 enters the high-pressure superheater 111 and is further heated to form high-pressure superheated steam. Then the high-pressure superheated steam enters the high-pressure cylinder 141 and the low-pressure cylinder 142 of the steam turbine in sequence to do work, driving the second generator 143 to generate electricity. The low-pressure saturated steam formed by heating in the low-pressure evaporator 116 enters the low-pressure superheater 115 and is further heated to form low-pressure superheated steam. Then the low-pressure superheated steam enters the low-pressure cylinder 142 of the steam turbine to do work, driving the second generator 143 to generate electricity. At this time, the flow rates of the high-pressure superheated steam and the low-pressure superheated steam entering the steam turbine generator set 14 both decrease, thereby reducing the operating load of the steam turbine generator set 14. The exhaust steam discharged after doing work by the steam turbine generator set 14 enters the condenser 15 and forms condensate. The eighteenth valve 46 is opened simultaneously, and then it is transported to the deaerator 19 by the circulating water pump 16 for heating, and then transported to the feed water preheater 20 by the third water pump 22 and further heated by the flue gas waste heat from the steam generator 21 to form high-temperature feed water for recycling; the thirteenth valve 41, the fourteenth valve 42 and the seventeenth valve 45 are opened simultaneously. The high-temperature feed water from the feed water preheater 20 is also transported to the medium-pressure evaporator 114 and heated to form medium-pressure saturated steam, and then enters the medium-pressure superheater 113 and is further heated to form medium-pressure superheated steam. Finally, the medium-pressure superheated steam is transported to the high-pressure industrial steam user 26 for external heat supply through the high-pressure industrial steam supply pipe 25. The low-pressure superheated steam output by the low-pressure superheater 115 is also transported to the low-pressure industrial steam user 28 for external heat supply through the low-pressure industrial steam supply pipe 27.

[0043] The twenty-first valve 49 and the twenty-second valve 50 are opened simultaneously. The high-temperature feed water from the feed water preheater 20 is also transported to the steam generator 21 and heated by the flue gas waste heat from the molten salt type waste heat boiler 2 to form saturated steam, and then transported to the deaerator 19 for heating the circulating water in the deaerator 19.

[0044] Specifically, when the steam turbine generator set 14 reduces the 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 high-pressure industrial steam user 26 and the low-pressure industrial steam user 28, the twentieth valve 48 is opened, and the excess feed water is stored using the circulating water storage tank 18; when the steam turbine generator set 14 reduces the 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 high-pressure industrial steam user 26 and the low-pressure industrial steam user 28, the nineteenth valve 47 is opened, and the circulating water storage tank 18 is used to supplement the lacking amount of feed water.

[0045] When the thermal power plant participates in power peak shaving and needs to increase the grid-connected power load, the gas turbine generator set 1 operates at a high load, and the grid-connected power load is increased by increasing the operating load of the steam turbine generator set 14. At this time, the molten salt thermal energy storage device releases heat and also participates in heat exchange, that is: at this time, the third valve 31, the fourth valve 32, the fifth valve 33, the sixth valve 34, the low-temperature molten salt pump 4 and the high-temperature molten salt pump 8 are opened, and the low-temperature heater 5, the high-temperature heater 6, the high-temperature molten salt bypass pipe 10, the molten salt-steam heat exchange mechanism 11 and the low-temperature molten salt bypass pipe 9 form a closed loop, and the low-temperature molten salt storage tank 3 and the high-temperature molten salt storage tank 7 participate in the use. At the same time, the seventh valve 35, the eighth valve 36, the ninth valve 37 and the tenth valve 38 are opened. The high-temperature molten salt from the high-temperature heater 6 and the high-temperature molten salt from the high-temperature molten salt storage tank 7 converge and then enter the high-pressure superheater 111 for the first-stage cooling. Thus, heat is released through the molten salt thermal energy storage device to increase the amount of high-temperature molten salt transported to the molten salt-steam heat exchange mechanism 11, thereby increasing the amount of superheated steam transported from the molten salt-steam heat exchange mechanism 11 to the steam turbine generator set 14, to further increase the operating load of the steam turbine generator set 14. The high-temperature molten salt after being cooled by the high-pressure superheater 111 is divided into two paths and enters the high-pressure evaporator 112 and the medium-pressure superheater 113 respectively for the second-stage cooling. The high-temperature molten salt after being cooled by the high-pressure evaporator 112 then enters the low-pressure superheater 115 for the third-stage cooling. The high-temperature molten salt after being cooled by the medium-pressure superheater 113 then enters the medium-pressure evaporator 114 for the third-stage cooling. The high-temperature molten salt after being cooled by the low-pressure superheater 115 and the medium-pressure evaporator 114 converges and then enters the low-pressure evaporator 116 for the fourth-stage cooling. Finally, the low-temperature molten salt is formed and divided into two paths. One path returns to the low-temperature molten salt storage tank 3 for storage, and the other path passes through the low-temperature molten salt bypass pipe 9 and is driven by the low-temperature molten salt pump 4 to return to the molten salt waste heat boiler 2 again, and then is heated by the low-temperature heater 5 and the high-temperature heater 6 to form high-temperature molten salt for recycling.

[0046] The eleventh valve 39, the twelfth valve 40, the fifteenth valve 43 and the sixteenth valve 44 are opened simultaneously. The high-temperature feed water from the feed water preheater 20 enters the high-pressure evaporator 112 and the low-pressure evaporator 116 respectively and is heated. The high-pressure saturated steam formed by heating in the high-pressure evaporator 112 enters the high-pressure superheater 111 and is further heated to form high-pressure superheated steam. Then, the high-pressure superheated steam enters the high-pressure cylinder 141 and the low-pressure cylinder 142 of the steam turbine in sequence to do work, so as to drive the second generator 143 to generate electricity. The low-pressure saturated steam formed by heating in the low-pressure evaporator 116 enters the low-pressure superheater 115 and is further heated to form low-pressure superheated steam. Then, the low-pressure superheated steam enters the low-pressure cylinder 142 of the steam turbine to do work, so as to drive the second generator 143 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 14 increase, thereby increasing the operating load of the steam turbine generator set 14. The exhaust steam discharged after doing work by the steam turbine generator set 14 enters the condenser 15 and forms condensate. The eighteenth valve 46 is opened simultaneously, and then it is conveyed to the deaerator 19 by the circulating water pump 16 for heating, and then conveyed to the feed water preheater 20 by the third water pump 22 and is further heated by the flue gas waste heat from the steam generator 21 to form high-temperature feed water for recycling; the thirteenth valve 41, the fourteenth valve 42 and the seventeenth valve 45 are opened simultaneously. The high-temperature feed water from the feed water preheater 20 is also conveyed to the medium-pressure evaporator 114 and is heated to form medium-pressure saturated steam, and then enters the medium-pressure superheater 113 and is further heated to form medium-pressure superheated steam. Finally, the medium-pressure superheated steam is conveyed to the high-pressure industrial steam user 26 for external heat supply through the high-pressure industrial steam supply pipe 25. The low-pressure superheated steam output by the low-pressure superheater 115 is also conveyed to the low-pressure industrial steam user 28 for external heat supply through the low-pressure industrial steam supply pipe 27.

[0047] The twenty-first valve 49 and the twenty-second valve 50 are opened simultaneously. The high-temperature feed water from the feed water preheater 20 is also conveyed to the steam generator 21 and is heated by the flue gas waste heat from the molten salt type waste heat boiler 2 to form saturated steam, and then conveyed to the deaerator 19 to be used for heating the circulating water in the deaerator 19.

[0048] The nineteenth valve 47 is opened simultaneously. The circulating water storage tank 18 is used to supplement water for the deaerator 19, and at the same time, the water supply required for heating the high-pressure industrial steam user 26 and the low-pressure industrial steam user 28 and the water supply required for the increase in the steam demand due to the increase in the operating load of the steam turbine generator set 14 are supplemented.

[0049] The above embodiments are only the preferred embodiments of the present invention, and the protection scope of the present invention cannot be limited thereby. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention belong to the protection scope required by the present invention.

Claims

1. A molten salt thermal energy storage coupled thermal power peak shaving system based on multi-parameter heat supply, characterized in that It includes a gas turbine generator set, a molten salt waste heat boiler, a molten salt thermal energy storage device, a molten salt-steam heat exchange mechanism, a steam turbine generator set and a circulating water supply pipeline. The flue gas outlet of the gas turbine generator set is communicated with the flue gas inlet of the molten salt waste heat boiler; The molten salt thermal energy storage device includes a low-temperature molten salt storage tank, a low-temperature molten salt pump, a low-temperature heater, a high-temperature heater, a high-temperature molten salt storage tank and a high-temperature molten salt pump which are connected in sequence. 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. 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; The molten salt-steam heat exchange mechanism includes a high-pressure superheater, a high-pressure evaporator, a medium-pressure superheater, a medium-pressure evaporator, a low-pressure superheater and a low-pressure evaporator. The molten salt inlet of the high-pressure superheater is communicated with the molten salt outlet of the high-temperature molten salt pump. The molten salt outlet of the high-pressure superheater is communicated with both the molten salt inlet of the medium-pressure superheater and the molten salt inlet of the high-pressure evaporator. The molten salt outlet of the medium-pressure superheater is communicated with the molten salt inlet of the medium-pressure evaporator. The molten salt outlet of the high-pressure evaporator is communicated with the molten salt inlet of the low-pressure superheater. The molten salt outlets of the medium-pressure evaporator and the low-pressure superheater are both communicated with the molten salt outlet of the low-pressure evaporator. The molten salt outlet of the low-pressure evaporator is communicated with the molten salt inlet of the low-temperature molten salt storage tank; The water inlet of the high-pressure evaporator is communicated with a first water pump. The water inlet of the medium-pressure evaporator is communicated with a second water pump. The water inlets of the first water pump, the second water pump and the low-pressure evaporator are all communicated with the water inlet of the circulating water supply pipeline. The steam outlet of the high-pressure evaporator is communicated with the steam inlet of the high-pressure superheater. The steam outlet of the high-pressure superheater is communicated with the high-pressure steam inlet of the steam turbine generator set. The steam outlet of the medium-pressure evaporator is communicated with the steam inlet of the medium-pressure superheater. The steam outlet of the medium-pressure superheater is communicated with a high-pressure industrial steam user. The steam outlet of the low-pressure evaporator is communicated with the steam inlet of the low-pressure superheater. The steam outlet of the low-pressure superheater is communicated with the medium-low pressure steam inlet of the steam turbine generator set through a low-pressure superheated steam main pipe. The low-pressure superheated steam main pipe is communicated with a low-pressure industrial steam user.

2. The peak shaving system according to claim 1, wherein, The circulating water supply pipeline includes a condenser, a circulating water pump, a makeup water pump, a circulating water storage tank, a deaerator, a third water pump and a feed water preheater. The exhaust steam inlet of the condenser is communicated with the exhaust port of the steam turbine generator set. The condenser, the circulating water pump, the deaerator, the third water pump and the feed water preheater are connected in sequence. The water outlet of the feed water preheater is communicated with the water inlets of the first water pump, the second water pump and the low-pressure evaporator. A makeup water pipe is communicated between the water outlet of the circulating water storage tank and the water inlet of the deaerator. The makeup water pump is connected to the makeup water pipe.

3. The peak shaving system according to claim 2, wherein, The water inlet of the circulating water storage tank is also communicated with the water outlet of the circulating water pump.

4. The peak shaving system according to claim 2, wherein The flue gas outlet of the molten salt waste heat boiler is also connected to a steam generator. The water inlet of the steam generator is connected to the water outlet of the feed water preheater, and the steam outlet of the steam generator is connected to the steam inlet of the deaerator.

5. The peak shaving system according to claim 4, wherein The flue gas inlet of the feed water preheater is connected to the flue gas outlet of the steam generator, and the flue gas outlet of the feed water preheater is connected to the outside.

6. The peak shaving system according to claim 1, characterized in that, The gas turbine generator set includes a gas turbine compressor, a gas turbine combustor, a gas turbine turbine, and a first generator. The exhaust port of the gas turbine compressor is connected to the intake port of the gas turbine combustor. The exhaust port of the gas turbine combustor is connected to the intake port of the gas turbine turbine. The gas turbine turbine is coaxially connected to the gas turbine compressor. The gas turbine compressor and the gas turbine turbine jointly drive the first generator to generate electricity. The exhaust port of the gas turbine turbine is connected to the flue gas inlet of the molten salt waste heat boiler.

7. The peak shaving system according to claim 1, wherein The steam turbine generator set includes a steam turbine intermediate-high pressure cylinder, a steam turbine low pressure cylinder, and a second generator. The steam inlet of the steam turbine intermediate-high pressure cylinder is connected to the steam outlet of the high-pressure superheater. The exhaust port of the steam turbine intermediate-high pressure cylinder is connected to the steam inlet of the steam turbine low pressure cylinder. The steam inlet of the steam turbine low pressure cylinder is connected to the low-pressure superheated steam header. The steam turbine intermediate-high pressure cylinder and the steam turbine low pressure cylinder are coaxially connected to the second generator. The exhaust port of the steam turbine low pressure cylinder is connected to the steam inlet of the circulating water supply pipeline.

8. A method for a molten salt thermal energy storage coupled thermal power peak shaving system based on multi-parameter heat supply according to any one of claims 1-7, characterized in that, Comprising: 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 to ensure the high-efficiency operation of the thermal power plant. At this time, the molten salt energy storage device does not store or release heat, but only exchanges heat. The medium-pressure superheater provides high-pressure steam for the high-pressure industrial steam users, and the low-pressure superheated steam header provides low-pressure steam for the low-pressure industrial steam users. When the thermal power plant participates in power peak regulation and needs to reduce the on-grid power load, the gas turbine generator set operates at high load, and the on-grid power load is reduced by reducing the operating load of the steam turbine generator set. At this time, the molten salt energy storage device not only stores heat but also participates in heat exchange, thereby reducing the on-grid load. The medium-pressure superheater provides high-pressure steam for the high-pressure industrial steam users, and the low-pressure superheated steam header provides low-pressure steam for the low-pressure industrial steam users. When the thermal power plant participates in power peak regulation and needs to increase the on-grid power load, the gas turbine generator set operates at high load, and the on-grid power load is increased by increasing the operating load of the steam turbine generator set. At this time, the molten salt energy storage device releases heat and also participates in heat exchange, thereby increasing the on-grid power load. The medium-pressure superheater provides high-pressure steam for the high-pressure industrial steam users, and the low-pressure superheated steam header provides low-pressure steam for the low-pressure industrial steam users.

9. The method of the peak shaving system according to claim 8, wherein, When the thermal power plant participates in power peak regulation and needs to reduce the on-grid power load, the high-temperature molten salt from the high-temperature heater enters the high-temperature molten salt storage tank for heat storage, and the other part enters the high-pressure superheater through the high-temperature molten salt bypass pipe for the first-stage cooling, and then is divided into two paths to enter the high-pressure evaporator and the medium-pressure superheater respectively for the second-stage cooling. The high-temperature molten salt cooled by the high-pressure evaporator then enters the low-pressure superheater for the third-stage cooling, and the high-temperature molten salt cooled by the medium-pressure superheater then enters the medium-pressure evaporator for the third-stage cooling. The high-temperature molten salt cooled by the low-pressure superheater and the medium-pressure evaporator converges and then enters the low-pressure evaporator for the fourth-stage cooling. The finally 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 is driven by the low-temperature molten salt pump and returns to the molten salt waste heat boiler again. After being heated by the low-temperature heater and the high-temperature heater in sequence to form high-temperature molten salt, it then enters the high-temperature molten salt storage tank for storage and enters the high-pressure superheater for recycling respectively.

10. The method of the peak shaving system according to claim 8, characterized in that When the thermal power plant participates in power peak regulation and needs to increase the on-grid power load, the high-temperature molten salt from the high-temperature heater converges with the high-temperature molten salt from the high-temperature molten salt storage tank and enters the high-pressure superheater for the first-stage cooling. Thus, heat is released through the molten salt heat storage device to increase the amount of high-temperature molten salt transported to the molten salt steam heat exchange mechanism, thereby increasing the amount of superheated steam transported from the molten salt steam heat exchange mechanism to the steam turbine generator set, to further increase the operating load of the steam turbine generator set. The high-temperature molten salt cooled by the high-pressure superheater is divided into two paths to enter the high-pressure evaporator and the medium-pressure superheater respectively for the second-stage cooling. The high-temperature molten salt cooled by the high-pressure evaporator then enters the low-pressure superheater for the third-stage cooling, and the high-temperature molten salt cooled by the medium-pressure superheater then enters the medium-pressure evaporator for the third-stage cooling. The high-temperature molten salt cooled by the low-pressure superheater and the medium-pressure evaporator converges and then enters the low-pressure evaporator for the fourth-stage cooling. The finally 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 is driven by the low-temperature molten salt pump and returns to the molten salt waste heat boiler again. Then, it is heated by the low-temperature heater and the high-temperature heater to form high-temperature molten salt for recycling again.

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