Peak shaving system based on steam heat storage and fused salt heat storage and operation method

Abstract

The invention discloses a peak shaving system based on steam heat storage and fused salt heat storage and an operation method. According to the peak shaving system, one end of a main steam pipeline is connected with a steam turbine generator unit, the other end of the main steam pipeline is connected with the input end of a first temperature and pressure reducing device, and the output end of the first temperature and pressure reducing device is connected with the input end of a steam heat accumulator; the steam output end of the steam heat accumulator is connected with the steam input end of the fused salt heat storage device, and the saturated water output end of the steam heat accumulator is connected with the saturated water input end of the fused salt heat storage device; during heat storage peak regulation, steam heat storage and fused salt electric heat storage are used for reducing the power capability of a steam turbine and the on-grid power of a generator at the same time, and during heat release peak, through the combination of the steam heat accumulator and the fused salt heat storage subsystem, the steam heat accumulator provides saturated steam, the saturated steam is heated into superheated steam, and the superheated steam is stored in the fused salt heat storage subsystem. And superheated steam and / or steam quantity of various qualities can be provided under the same fused salt heat storage quantity, so that the electric and thermal load operation domain of the unit is further widened.

Description

TECHNICAL FIELD

[0001] The present application relates to a peak regulation system based on steam accumulation and molten salt heat storage and an operation method thereof, and belongs to the technical field of multi-element heat storage. BACKGROUND

[0002] Under the background of new power system construction, more and more thermal power units begin to be flexibly modified by coupling heat storage. Steam accumulation and molten salt heat storage are two important technical means in the field of heat storage. However, the steam accumulator can only release saturated steam, and the quality thereof does not meet the requirements of unit peak, heat supply and industrial steam supply. Although the molten salt heat storage technology can generate high-temperature superheated steam, the heat storage process thereof undergoes conversion of thermal energy-mechanical energy-electric energy-thermal energy, and the energy loss is large. Or, the steam heat energy-thermal energy conversion is used, the steam consumption is large, and the molten salt is only suitable for medium-temperature molten salt. In the heat release process, the subcooled water needs to be heated to saturated water, and then to superheated steam, and the heat consumption is large, resulting in a large amount of molten salt. SUMMARY

[0003] The present application aims to overcome the deficiencies of the prior art and provide a peak regulation system based on steam accumulation and molten salt heat storage and an operation method thereof. To achieve the above-mentioned object / To solve the above-mentioned technical problems, the present application is realized by the following technical scheme: First aspect: a peak regulation system based on steam accumulation and molten salt heat storage, characterized in that it comprises a main steam pipeline, a steam turbine generator unit, a steam accumulator, a molten salt heat storage device, a first temperature and pressure reducing device and a second temperature and pressure reducing device. One end of the main steam pipeline is connected with the steam turbine generator unit, the other end is connected with the input end of the first temperature and pressure reducing device, and a high-pressure electric isolation valve, a first valve and a first electric regulating valve are sequentially arranged on the connecting pipeline. The output end of the first temperature and pressure reducing device is connected with the input end of the steam accumulator, and the steam flow sent to the steam accumulator is adjusted by the first electric regulating valve. The steam output end of the steam accumulator is connected with the steam input end of the molten salt heat storage device, and a second valve and a second electric regulating valve are sequentially arranged on the connecting pipeline. The water side output end of the steam accumulator is connected with the water side input end of the molten salt heat storage device, and a water supply pump, a third valve and a third electric regulating valve are sequentially arranged on the connecting pipeline.

[0004] Optionally, the steam turbine generator unit comprises a high-pressure cylinder, a medium-pressure cylinder, a low-pressure cylinder and a generator connected in sequence. The high-pressure cylinder is connected with a steam reheater through a cold re-piping. The output end of the steam reheater is connected with the medium-pressure cylinder.

[0005] Optionally, the molten salt heat storage device comprises a high-temperature molten salt storage tank, a molten salt-steam heat exchange assembly, a low-temperature molten salt storage tank, a molten salt electric heater, a low-temperature molten salt circulating pump and a high-temperature molten salt circulating pump, the output end of the low-temperature molten salt storage tank is connected with the input end of the molten salt electric heater, and is provided with a low-temperature molten salt circulating pump and a fourth valve, the output end of the molten salt electric heater is connected with the input end of the high-temperature molten salt storage tank, and is provided with a fifth valve, the output end of the high-temperature molten salt storage tank is connected with the molten salt input end of the molten salt-steam heat exchange assembly, and is provided with a high-temperature molten salt circulating pump and a sixth valve, the molten salt output end of the molten salt-steam heat exchange assembly is connected with the input end of the low-temperature molten salt storage tank, and is provided with a seventh valve.

[0006] Optionally, the first superheated steam output end of the molten salt-steam heat exchange assembly is connected with the input end of a second desuperheating and pressure reducing device, and is sequentially provided with a twelfth valve and an eighth electric regulating valve on the connecting pipeline, the output end of the second desuperheating and pressure reducing device is connected with a steam turbine generator set in one way, and is sequentially provided with a fourteenth valve, a tenth electric regulating valve and a third check valve on the connecting pipeline, and is provided with a thirteenth valve and a ninth electric regulating valve to provide heat supply / low-pressure industrial steam externally in another way; The second superheated steam output end of the molten salt-steam heat exchange assembly is connected on a cold re-piping line between a high-pressure cylinder and a steam reheater, and is sequentially provided with an eighth valve, a fourth electric regulating valve, a ninth valve, a fifth electric regulating valve and a first check valve on the connecting pipeline; high-pressure steam is externally output between the fourth electric regulating valve and the ninth valve, and is sequentially provided with a tenth valve and a sixth electric regulating valve on the connecting pipeline; The third superheated steam output end of the molten salt-steam heat exchange assembly is connected with a medium-pressure cylinder, and is sequentially provided with an eleventh valve, a seventh electric regulating valve and a first check valve on the connecting pipeline.

[0007] Optionally, the molten salt-steam heat exchange assembly comprises a module one and a module two, the input ends of the module one and the module two are connected with a high-temperature molten salt main pipe, and the output ends of the module one and the module two enter a low-temperature molten salt main pipe.

[0008] Optionally, the module one comprises an eleventh electric regulating valve and a molten salt-low-pressure steam superheater, the output end of the molten salt-low-pressure steam superheater is a first superheated steam output end, the input end is connected with the steam input end of the molten salt heat storage device, high-temperature molten salt becomes low-temperature molten salt after heat release through the molten salt-low-pressure steam superheater, and enters the low-temperature molten salt main pipe; the saturated steam output by the steam heat accumulator is heated into superheated steam through the molten salt-low-pressure steam superheater, and is output from the first superheated steam output end.

[0009] Optionally, the module two comprises a molten salt-high pressure steam generator, a molten salt-high pressure steam first superheater and a molten salt-high pressure steam second superheater, the molten salt-high pressure steam second superheater is connected with the high-temperature molten salt main pipe and is provided with a gate valve and a fifteenth valve, another branch is connected with the gate valve and the fifteenth valve in parallel and enters the molten salt-high pressure steam first superheater and is provided with a twelfth electrically controlled valve, the molten salt output end of the molten salt-high pressure steam first superheater is connected with the molten salt input end of the molten salt-high pressure steam generator, and the molten salt output end of the molten salt-high pressure steam generator is connected with the low-temperature molten salt main pipe; the saturated water of the steam accumulator is sequentially input into the molten salt-high pressure steam generator and the molten salt-high pressure steam first superheater, the steam output end of the molten salt-high pressure steam first superheater outputs steam through the second superheated steam output end, and another branch enters the molten salt-high pressure steam second superheater and is provided with a thirteenth electrically controlled valve, and after being heated into high-pressure high-overheated superheated steam, the steam is output from the third superheated steam output end.

[0010] The second aspect is a running method of the peak shaving system. When the generator set needs to be peak shaved, the high-pressure electric isolation valve, the first valve, the fourth valve, the fifth valve and the low-temperature molten salt circulating pump are opened, the second valve, the second electrically controlled valve, the third valve, the third electrically controlled valve, the sixth valve and the seventh valve are closed, the steam flow rate drawn from the main steam pipe is adjusted through the first electrically controlled valve, and the drawn main steam is stored in the steam accumulator after passing through the first desuperheating and pressure reducing device; the molten salt electric heater heats the low-temperature molten salt from the low-temperature molten salt storage tank into high-temperature molten salt by using the power generation of the steam turbine generator set, and reduces the power generation on-grid output. When the peak operation is performed, the first valve, the first electrically controlled valve, the fourth valve, the fifth valve, the fifteenth valve, the low-temperature molten salt circulating pump, the third valve and the third electrically controlled valve are closed, and the sixth valve, the seventh valve, the high-temperature molten salt circulating pump, the second valve, the second electrically controlled valve and the eleventh electrically controlled valve are opened, and the second electrically controlled valve adjusts the saturated steam flow rate entering the molten salt-steam heat exchange assembly. The saturated steam generated by the steam accumulator enters the molten salt-steam heat exchange assembly to be heated into low-pressure superheated steam, and then is output through the first superheated steam output end of the molten salt-steam heat exchange assembly, is desuperheated and pressure reduced through the second desuperheating and pressure reducing device, and replaces the heating / low-pressure industrial steam extraction, and then, and / or directly enters the low-pressure cylinder to increase the power output of the low-pressure cylinder.

[0011] Optionally, the peak operation method further comprises: The second peak operation method is characterized in that the second valve, the second electric valve, and the eleventh electric valve are closed, the third valve and the third electric valve are opened, and the stored water at the bottom of the steam accumulator is transported to the water side input end of the molten salt-steam water heat exchange assembly through the water supplementing pump.

[0012] Optionally, the peak operation method further comprises, based on the second peak operation method, opening the gate valve, fully opening the thirteenth electric valve, and closing the twelfth electric valve, the eleventh valve, and the seventh electric valve, wherein the high-pressure low-overheating superheated steam generated by the high-pressure steam first superheater is changed into high-pressure high-overheating superheated steam through the high-pressure steam second superheater, and is output to the medium-pressure cylinder through the third superheated steam output end of the molten salt-steam water heat exchange assembly.

[0013] Compared with the prior art, the present application has the following beneficial effects: 1. During heat storage peak shaving, the steam accumulator and the molten salt electric heat storage are used to simultaneously reduce the power of the steam turbine and the power of the generator, thereby increasing the heat storage peak shaving capacity, and the frequency modulation can be achieved to a certain extent through the molten salt electric heater.

[0014] 2. During heat release peak shaving, the steam accumulator and the molten salt heat storage subsystem are combined, the steam accumulator provides saturated steam and / or saturated water, and the molten salt heat storage subsystem heats the saturated steam and / or saturated water into superheated steam of different qualities, thereby providing superheated steam of multiple qualities and / or more superheated steam under the same molten salt heat storage capacity.

[0015] 3. The electric and thermal load operation domain of the unit is further widened. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 FIG. 1 is a schematic diagram of the system of an embodiment of the present application; Figure 2 FIG. 2 is a schematic diagram of the molten salt-steam water heat exchange assembly in the embodiment of the present application.

[0017] In the figure, 11 is a high-pressure cylinder, 12 is a medium-pressure cylinder, 13 is a low-pressure cylinder, 14 is a generator, 15 is a steam reheater, 21, steam accumulator; 22, low-temperature molten salt storage tank; 23, molten salt-steam heat exchange assembly; 231, first superheated steam output end; 232, second superheated steam output end; 233, third superheated steam output end; 2301, molten salt-low-pressure steam superheater; 2302, molten salt-high-pressure steam generator; 2303, molten salt-high-pressure steam first superheater; 2304, molten salt-high-pressure steam second superheater; 24, high-temperature molten salt storage tank; 25, molten salt electric heater; 3, pump and valve assembly; 31, high-temperature molten salt circulating pump; 32, low-temperature molten salt circulating pump; 33, water replenishing pump; 341, first valve; 342, second valve; 343, third valve; 344, fourth valve; 345, fifth valve; 346, sixth valve; 347, seventh valve; 348, eighth valve; 349, ninth valve; 3410, tenth valve; 3411, eleventh valve; 3412, twelfth valve; 3413, thirteenth valve; 3414, fourteenth valve; 3415, fifteenth valve; 351, first electrically-controlled valve; 352, second electrically-controlled valve; 353, third electrically-controlled valve; 354, fourth electrically-controlled valve; 355, fifth electrically-controlled valve; 356, sixth electrically-controlled valve; 357, seventh electrically-controlled valve; 358, eighth electrically-controlled valve; 359, ninth electrically-controlled valve; 3510, tenth electrically-controlled valve; 3511, eleventh electrically-controlled valve; 3512, twelfth electrically-controlled valve; 3513, thirteenth electrically-controlled valve; 361, first check valve; 362, second check valve; 363, third check valve; 37, high-pressure electrically-controlled isolation valve; 381, gate valve; 41, first desuperheating and pressure-reducing device; 42, second desuperheating and pressure-reducing device; 51, cold re-piping; 52, second piping; 53, third piping; 54, fourth piping; 55, fifth piping; 56, sixth piping; 57, seventh piping. DETAILED DESCRIPTION

[0018] In order to make the technical means, creative features, purposes and effects of the present application easy to understand, the present application is further described below in conjunction with specific embodiments.

[0019] In the description of the present application, it needs to be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" and the like are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" and the like can be explicitly or implicitly included one or more. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0020] In the description of the present application, it needs to be understood that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood through specific circumstances.

[0021] Embodiment 1, see Figure 1 The embodiment of the present application provides a peak regulation system based on steam heat storage and molten salt heat storage, which comprises a main steam pipeline, a steam turbine generator set, a steam accumulator 21, a molten salt heat storage device and a desuperheating and pressure reducing device. The steam turbine generator set comprises a high-pressure cylinder 11, a medium-pressure cylinder 12, a low-pressure cylinder 13, a generator 14, a steam reheater 15 and a cold re-pipeline 51, and the steam reheater 15 is arranged between the high-pressure cylinder 11 and the medium-pressure cylinder 12. In order to meet the demand of rapid peak regulation, the molten salt heat storage device comprises a high-temperature molten salt storage tank 24, a molten salt-steam water heat exchange assembly 23, a low-temperature molten salt storage tank 22, a molten salt electric heater 25, a low-temperature molten salt circulating pump 32, a high-temperature molten salt circulating pump 31 and other valves and pipelines, the molten salt electric heater 25 preferentially selects unit power generation by electricity, and the molten salt-steam water heat exchange assembly 23 has three superheated steam output ends, which are a first superheated steam output end 231, a second superheated steam output end 232 and a third superheated steam output end 233.

[0022] The main steam pipeline is connected with the input end of the first desuperheating and decompressing device 41, and a high-voltage electric isolation valve 37, a first valve 341 and a first electric regulating valve 351 are arranged on the connecting pipeline; the output end of the first desuperheating and decompressing device 41 is connected with the input end of the steam accumulator 21, and the steam flow sent to the steam accumulator 21 is adjusted by the first electric regulating valve 351.

[0023] The low-temperature molten salt storage tank 22 is connected with the input end of the molten salt electric heater 25, and a low-temperature molten salt circulating pump 32 and a fourth valve 344 are arranged; the output end of the molten salt electric heater 25 is connected with the input end of the high-temperature molten salt storage tank 24, and a fifth valve 345 is arranged; the output end of the high-temperature molten salt storage tank 24 is connected with the molten salt input end of the molten salt-steam heat exchange assembly 23, and a high-temperature molten salt circulating pump 31 and a sixth valve 346 are arranged; the molten salt output end of the molten salt-steam heat exchange assembly 23 is connected with the input end of the low-temperature molten salt storage tank 22, and a seventh valve 347 is arranged.

[0024] The steam output end of the steam accumulator 21 is connected with the steam input end of the molten salt-steam heat exchange assembly 23, and a second valve 342 and a second electric regulating valve 352 are arranged; the second electric regulating valve 352 is used to adjust the flow of saturated steam sent from the steam accumulator 21 to the molten salt-steam heat exchange assembly 23; The water side output end of the steam accumulator 21 is connected with the water side input end of the molten salt-steam heat exchange assembly 23, and a water supplementing pump 33, a third valve 343 and a third electric regulating valve 353 are arranged.

[0025] The embodiment of the present application provides a routing schematic diagram of the molten salt-steam heat exchange assembly 23, which is shown in Figure 2 .

[0026] The high-temperature molten salt enters the high-temperature molten salt main pipeline through the molten salt input end of the molten salt-steam heat exchange assembly 23, and then enters the module 1 and the module 2 through branches. The module 1 mainly comprises an eleventh electric regulating valve 3511 and a molten salt-low-pressure steam superheater 2301; the module 2 mainly comprises a fifteenth valve 3415, a gate valve 381, a twelfth electric regulating valve 3512, a thirteenth electric regulating valve 3513, a molten salt-high-pressure steam generator 2302, a molten salt-high-pressure steam first superheater 2303 and a molten salt-high-pressure steam second superheater 2304. The low-temperature molten salt after heat release enters the low-temperature molten salt main pipeline, and then is output through the molten salt output end of the molten salt-steam heat exchange assembly 23. The eleventh electric regulating valve 3511 is used to adjust the flow of the high-temperature molten salt distributed into the module 1 and the module 2; the gate valve 381 is used to close the gate valve 381 and the thirteenth electric regulating valve 3513 and open the twelfth electric regulating valve 3512 when high-pressure high-overheating superheated steam is not needed, so as to isolate the molten salt-high-pressure steam second superheater 2304.

[0027] For module one, high temperature molten salt becomes low temperature molten salt after heat release through molten salt-low pressure steam superheater 2301, and enters low temperature molten salt main pipe; saturated steam output by steam accumulator 21 is heated into superheated steam through molten salt-low pressure steam superheater 2301, and is output from first superheated steam output end 231.

[0028] For module two, high temperature molten salt enters molten salt-high pressure steam second superheater 2304 through fifteenth valve 3415, and is connected to low temperature molten salt main pipe through molten salt-high pressure steam generator 2302; saturated water output by steam accumulator 21 is heated into high pressure low superheat superheated steam through molten salt-high pressure steam generator 2302 and molten salt-high pressure steam first superheater 2303, and is output from third superheated steam output end 233 through molten salt-high pressure steam second superheater 2304.

[0029] In order to meet the peak demand, first superheated steam output end 231 of molten salt-steam water heat exchange assembly 23 is connected to sixth pipeline 56, and twelfth valve 3412, eighth electric regulating valve 358 and second desuperheating and pressure reducing device 42 are arranged on sixth pipeline 56; sixth pipeline 56 is connected to seventh pipeline 57 and eighth pipeline 58, and thirteenth valve 5413 and ninth electric regulating valve 359 are arranged on seventh pipeline 57, and seventh pipeline 57 is connected to heating / low pressure industrial steam main pipe; eighth pipeline is connected to low pressure cylinder 13 inlet through fourteenth valve 3414, tenth electric regulating valve 3510 and third check valve 363; ninth electric regulating valve 359 and tenth electric regulating valve 3510 are used to adjust the steam flow rate entering low pressure cylinder 13 and / or heating / low pressure industrial steam main pipe.

[0030] In order to meet the peak demand, second superheated steam output end 232 of molten salt-steam water heat exchange assembly 23 is connected to second pipeline 52, and second pipeline is connected to medium pressure cylinder 12 inlet; eleventh valve 3411, seventh electric regulating valve 357 and second check valve 362 are arranged on second pipeline 52; seventh electric regulating valve 357 is used to adjust the steam flow rate entering medium pressure cylinder 12.

[0031] In order to meet the peak demand, the third superheated steam output end 233 of the molten salt-steam heat exchange assembly 23 is connected with the third pipeline 53, and the eighth valve 348 and the fourth electric regulating valve 354 are arranged on the third pipeline 53, the output end of the third pipeline 53 is connected with the fourth pipeline 54 and the fifth pipeline 55, the fourth pipeline 54 is provided with the ninth valve 349, the fifth electric regulating valve 355 and the first check valve 361, and is connected to the cold re-piping 51, and the fifth pipeline 55 is provided with the tenth valve 3410 and the sixth electric regulating valve 356, and is connected to the high-pressure industrial steam main pipe; the fifth electric regulating valve 355 and the sixth electric regulating valve 356 are used to adjust the steam flow distributed into the cold re-piping 51 and / or the high-pressure industrial steam main pipe.

[0032] In the embodiment 2, the operation method of the system is also provided, and the method comprises: When the generator set needs to be peak-regulated, the high-pressure electric isolation valve 37, the first valve 341, the fourth valve 344, the fifth valve 345 and the low-temperature molten salt circulating pump 32 are opened, the second valve 342, the second electric regulating valve 352, the third valve 343, the third electric regulating valve 353, the sixth valve 346 and the seventh valve 347 are closed, the steam flow extracted from the main steam pipe is adjusted through the first electric regulating valve 351, and the extracted main steam is stored in the steam accumulator 21 after passing through the first desuperheating and pressure-reducing device 41.

[0033] The molten salt electric heater 25 uses the power generation of the unit to heat the low-temperature molten salt in the low-temperature molten salt storage tank 24 into high-temperature molten salt and store the high-temperature molten salt in the high-temperature molten salt storage tank 22. By extracting the main steam, the power generation of the high-pressure cylinder 11, the medium-pressure cylinder 12 and the low-pressure cylinder 13 of the steam turbine can be quickly reduced; and the power generation of the generator can be further reduced through the molten salt electric heater 25.

[0034] When the generator set needs to be peak-regulated.

[0035] The peak-regulated operation mode 1; The first valve 341, the first electric regulating valve 351, the fourth valve 344, the fifth valve 345, the fifteenth valve 3415, the low-temperature molten salt circulating pump 32, the third valve 343 and the third electric regulating valve 353 are closed, the sixth valve 346, the seventh valve 347, the high-temperature molten salt circulating pump 31, the second valve 342, the second electric regulating valve 352 and the eleventh electric regulating valve 3511 are opened, and the second electric regulating valve 352 is used to adjust the saturated steam flow entering the molten salt-steam heat exchange assembly 23; The saturated steam generated by the steam accumulator 21 enters the molten salt-steam water heat exchange assembly 23 to be heated into low-pressure superheated steam, and then is output through the first superheated steam output end 231 of the molten salt-steam water heat exchange assembly 23. After the temperature and pressure are reduced by the second desuperheating and pressure reducing device 42, the low-pressure superheated steam preferentially replaces or partially replaces the industrial steam extraction, and then, and / or directly enters the low-pressure cylinder 13 to increase the power output of the low-pressure cylinder 13.

[0036] Peak operation mode 2; The second valve 342, the second electrically controlled valve 352 and the eleventh electric valve 3511 are closed, and the third valve 343 and the third electrically controlled valve 353 are opened. The stored water at the bottom of the steam accumulator 21 is transported to the water side input end of the molten salt-steam water heat exchange assembly 23 through the water supply pump 33. In the molten salt-steam water heat exchange assembly 23, the high-pressure saturated water is heated by the molten salt-high-pressure steam generator 2302 to become high-pressure saturated steam, and the high-pressure saturated steam is heated by the molten salt-high-pressure steam first superheater 2303 to become high-pressure low-overheating superheated steam. The molten salt-high-pressure steam second superheater 2304 is isolated by closing the gate valve 381 and the thirteenth electrically controlled valve 3513, and the molten salt flow entering the molten salt-high-pressure steam first superheater 2303 is adjusted by the twelfth electric valve 3512. The high-pressure low-overheating superheated steam is output to the third pipeline 53 through the second superheated steam output end 232 of the molten salt-steam water heat exchange assembly 23. When there is a demand for high-pressure industrial steam, the high-pressure low-overheating superheated steam preferentially replaces or partially replaces the high-pressure industrial steam extraction, and then, and / or enters the cold re-piping 51. If there is no demand for high-pressure industrial steam, the high-pressure low-overheating superheated steam enters the cold re-piping 51 through the fourth pipeline 54, is heated by the steam reheater 15, and then enters the medium-pressure cylinder 12 and the low-pressure cylinder 13 to increase the power output of the medium-pressure cylinder 12 and the low-pressure cylinder 13.

[0037] Peak operation mode 3; Based on the peak operation mode 2, the gate valve 381 is opened, the thirteenth electric valve 3513 is fully opened, the twelfth electric valve 3512, the eleventh valve 3411 and the seventh electric valve 357 are closed. The high-pressure low-overheating superheated steam generated by the high-pressure steam first superheater 2303 is heated by the high-pressure steam second superheater 2304 to become high-pressure high-overheating superheated steam. The high-pressure high-overheating superheated steam is output to the second pipeline 52 through the third superheated steam output end 233 of the molten salt-steam water heat exchange assembly 23, and directly enters the medium-pressure cylinder 12 through the second pipeline 52 to increase the power output of the medium-pressure cylinder 12 and the low-pressure cylinder 13.

[0038] The above-mentioned three peak operation modes are mainly obtained by controlling different valves, and therefore, the three peak operation modes can be operated independently or in combination. The actual demand of the unit can be determined.

[0039] The superheated steam generated by the molten salt-water heat exchange component 23 has the following three utilization modes: 1. Supplying low-pressure cylinder 13 for power generation and / or heat supply / low-pressure industrial steam; 2. Supplying cold re-piping 51, which is heated by the reheater 15 and then enters the medium-pressure cylinder 12 and the low-pressure cylinder 13 for power generation, and / or high-pressure industrial steam; 3. Directly supplying the medium-pressure cylinder 12 and the low-pressure cylinder 13 for power generation; The quality of the superheated steam generated by the molten salt-water heat exchange component 23 is different in different utilization modes, so the actual boundary conditions should be considered for the design of the molten salt-water heat exchange component 23 to meet the flexibility and / or heat supply / industrial steam supply requirements of the unit under different conditions.

[0040] The above only describes the preferred embodiments of the present application, and it should be noted that those skilled in the art can make several improvements and modifications without departing from the technical principles of the present application, and these improvements and modifications should also be considered within the protection scope of the present application.

Claims

1. A peak shaving system based on steam thermal storage and molten salt thermal storage, characterized in that, The main steam pipeline, the steam turbine generator unit, the steam accumulator, the molten salt heat storage device, the first temperature and pressure reducing device and the second temperature and pressure reducing device are included. One end of the main steam pipeline is connected with the steam turbine generator unit, the other end is connected with the input end of the first temperature and pressure reducing device, and a high-pressure electric isolation valve, a first valve and a first electric regulating valve are sequentially arranged on the connecting pipeline, the output end of the first temperature and pressure reducing device is connected with the input end of the steam accumulator, and the steam flow sent to the steam accumulator is adjusted by the first electric regulating valve; The steam output end of the steam accumulator is connected with the steam input end of the molten salt heat storage device, and a second valve and a second electric regulating valve are sequentially arranged on the connecting pipeline, the saturated water output end of the steam accumulator is connected with the saturated water input end of the molten salt heat storage device, and a water supply pump, a third valve and a third electric regulating valve are sequentially arranged on the connecting pipeline.

2. The steam accumulation and molten salt heat storage based peak shifting system according to claim 1, wherein, The steam turbine generator unit includes a high-pressure cylinder, a medium-pressure cylinder, a low-pressure cylinder and a generator which are sequentially connected, and the high-pressure cylinder is connected with a steam reheater through a cold reheat pipeline, and the output end of the steam reheater is connected with the medium-pressure cylinder.

3. The steam accumulation and molten salt thermal storage based peak shifting system according to claim 2, wherein, The molten salt heat storage device includes a high-temperature molten salt storage tank, a molten salt-steam water heat exchange assembly, a low-temperature molten salt storage tank, a molten salt electric heater, a low-temperature molten salt circulating pump and a high-temperature molten salt circulating pump, the output end of the low-temperature molten salt storage tank is connected with the input end of the molten salt electric heater, and is provided with a low-temperature molten salt circulating pump and a fourth valve, the output end of the molten salt electric heater is connected with the input end of the high-temperature molten salt storage tank, and is provided with a fifth valve, the output end of the high-temperature molten salt storage tank is connected with the molten salt input end of the molten salt-steam water heat exchange assembly, and is provided with a high-temperature molten salt circulating pump and a sixth valve, and the molten salt output end of the molten salt-steam water heat exchange assembly is connected with the input end of the low-temperature molten salt storage tank, and is provided with a seventh valve.

4. The system of claim 3, wherein, The first superheated steam output end of the molten salt-steam water heat exchange assembly is connected with the input end of the second temperature and pressure reducing device, and a twelfth valve and an eighth electric regulating valve are sequentially arranged on the connecting pipeline, the output end of the second temperature and pressure reducing device is connected with the steam turbine generator unit in one way, and a fourteenth valve, a tenth electric regulating valve and a third check valve are sequentially arranged on the connecting pipeline, and the other way is provided with heat supply / low-pressure industrial steam through a thirteenth valve and a ninth electric regulating valve; The second superheated steam output end of the molten salt-steam water heat exchange assembly is connected on the cold reheat pipeline between the high-pressure cylinder and the steam reheater, and an eighth valve, a fourth electric regulating valve, a ninth valve, a fifth electric regulating valve and a first check valve are sequentially arranged on the connecting pipeline; high-pressure steam is outputted outside between the fourth electric regulating valve and the ninth valve, and a tenth valve and a sixth electric regulating valve are sequentially arranged on the connecting pipeline; The third superheated steam output end of the molten salt-steam water heat exchange assembly is connected with the medium-pressure cylinder, and an eleventh valve, a seventh electric regulating valve and a first check valve are sequentially arranged on the connecting pipeline.

5. The steam accumulation and molten salt heat storage based peak shifting system according to claim 4, wherein, The molten salt-steam water heat exchange assembly includes a module one and a module two, the input ends of the module one and the module two are connected with a high-temperature molten salt main pipeline, and the output ends of the module one and the module two enter a low-temperature molten salt main pipeline.

6. The system of claim 5, wherein, The module one includes an eleventh electric regulating valve and a molten salt-low pressure steam superheater, an output end of the molten salt-low pressure steam superheater is a first superheated steam output end, and an input end is connected with a steam output end of a steam accumulator, high-temperature molten salt becomes low-temperature molten salt after heat release through the molten salt-low pressure steam superheater, and enters a low-temperature molten salt main pipe; saturated steam output by the steam accumulator is heated into superheated steam through the molten salt-low pressure steam superheater, and is output from the first superheated steam output end.

7. The system of claim 5, wherein, The module two includes a molten salt-high pressure steam generator, a molten salt-high pressure steam first superheater and a molten salt-high pressure steam second superheater, the molten salt-high pressure steam second superheater is connected with the high-temperature molten salt main pipe in one way, is provided with a gate valve and a fifteenth valve in another way, enters the molten salt-high pressure steam first superheater in parallel between the gate valve and the fifteenth valve, and is provided with a twelfth electric regulating valve, a molten salt output end of the molten salt-high pressure steam first superheater is connected with a molten salt input end of the molten salt-high pressure steam generator, and a molten salt output end of the molten salt-high pressure steam generator is connected with the low-temperature molten salt main pipe; saturated water of the steam accumulator is sequentially input to the molten salt-high pressure steam generator and the molten salt-high pressure steam first superheater, a steam output end of the molten salt-high pressure steam first superheater is output through a second superheated steam output end in one way, is input to the molten salt-high pressure steam second superheater in another way, is provided with a thirteenth electric regulating valve, is heated into high-pressure high-overheat superheated steam, and is output from a third superheated steam output end.

8. A method of operating a peak shaving system based on the system of claim 7, characterized in that, The method comprises: When the generator set needs to be peak-regulated, a high-pressure electric isolation valve, a first valve, a fourth valve, a fifth valve and a low-temperature molten salt circulating pump are opened, a second valve, a second electric regulating valve, a third valve, a third electric regulating valve, a sixth valve and a seventh valve are closed, a steam flow extracted from a main steam pipeline is adjusted through a first electric regulating valve, and the extracted main steam is stored in a steam accumulator after passing through a first temperature and pressure reducing device; the molten salt electric heater heats low-temperature molten salt from a low-temperature molten salt storage tank into high-temperature molten salt by using power generation of a steam turbine generator set, and reduces power generation on-grid output; When peak operation is performed, the first valve, the first electric regulating valve, the fourth valve, the fifth valve, the fifteenth valve, the low-temperature molten salt circulating pump, the third valve and the third electric regulating valve are closed, and the sixth valve, the seventh valve, a high-temperature molten salt circulating pump, the second valve, the second electric regulating valve and an eleventh electric regulating valve are opened, and the second electric regulating valve functions to adjust saturated steam flow entering a molten salt-steam water heat exchange assembly; Saturated steam generated by the steam accumulator is heated into low-pressure superheated steam through the molten salt-steam water heat exchange assembly, is then output through a first superheated steam output end of the molten salt-steam water heat exchange assembly, is reduced in temperature and pressure through a second temperature and pressure reducing device, replaces a heat supply / low-pressure industrial steam extraction, and is directly input into a low-pressure cylinder, thereby increasing a work output of the low-pressure cylinder.

9. The method according to claim 8, wherein, The peak operation method further comprises: The second peak operation method comprises closing the second valve, the second electric regulating valve and the eleventh electric valve, opening the third valve and the third electric regulating valve, and conveying the stored water at the bottom of the steam accumulator to the water side input end of the molten salt-water heat exchange assembly through the water supply pump. In the molten salt-water heat exchange assembly, the high-pressure saturated water is changed into high-pressure saturated steam after absorbing heat in the molten salt-high-pressure steam generator, and the high-pressure saturated steam is changed into high-pressure low-overheating superheated steam after absorbing heat in the molten salt-high-pressure steam first superheater. The molten salt-high-pressure steam second superheater is isolated by closing the gate valve and the thirteenth electric regulating valve, and the molten salt flow into the molten salt-high-pressure steam first superheater is adjusted through the twelfth electric valve. The high-pressure low-overheating superheated steam is output through the second superheated steam output end of the molten salt-water heat exchange assembly, and is used as high-pressure industrial steam extraction when there is a demand for high-pressure industrial steam, and then and / or enters the cold re-pipe. If there is no demand for high-pressure industrial steam, all enters the cold re-pipe, is heated through the steam reheater, and then enters the intermediate-pressure cylinder and the low-pressure cylinder.

10. The method according to claim 9, wherein, The peak operation method further comprises, based on the second peak operation method, opening the gate valve, fully opening the thirteenth electric valve, closing the twelfth electric valve, the eleventh valve and the seventh electric valve, and changing the high-pressure low-overheating superheated steam generated by the high-pressure steam first superheater into high-pressure high-overheating superheated steam after absorbing heat in the high-pressure steam second superheater, and outputting the high-pressure high-overheating superheated steam through the third superheated steam output end of the molten salt-water heat exchange assembly to enter the intermediate-pressure cylinder.

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