System for assisting energy storage peak regulation of high-temperature hot water tank by using fused salt and control method

Abstract

The invention discloses a system for assisting energy storage and peak regulation of a high-temperature hot water tank through fused salt and a control method, and belongs to the technical field of energy storage and peak regulation. The system comprises a unit power generation circulating system and a heat storage system. The heat storage system comprises a high-temperature hot water energy storage part and a fused salt energy storage part, and a high-temperature fused salt storage tank and a low-temperature fused salt storage tank are arranged in the fused salt energy storage part, so that part of heat of redundant steam of a boiler is stored in high-temperature fused salt when the unit operates at low load; the high-pressure and high-temperature steam after heat exchange with the high-temperature fused salt is bubbled in the water storage tank, water in the water storage tank is heated into high-temperature hot water, and therefore steam heat generated by the boiler is completely stored. When the unit is high in load and needs to release energy, high-temperature hot water in the high-temperature hot water tank is converted into saturated steam through the pressure reducer, then exchanges heat with the high-temperature fused salt and is heated into superheated steam, and the superheated steam enters the medium-pressure cylinder to expand and do work. The system can improve the peak regulation capacity of the unit and quickly realize the change of the unit response load.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage and peak shaving, and particularly to a molten salt-assisted high-temperature hot water tank energy storage and peak shaving system and control method for thermal power units. Background Art

[0002] The development of new energy impacts the traditional energy structure mainly based on thermal power. However, the volatility and randomness of new energy also limit the stable operation of the power grid. Therefore, energy storage technology and the flexibility transformation of thermal power plants have become important means to maintain the stable operation of the power grid and suppress the peak-valley difference of the power grid.

[0003] At present, the actual peak shaving capacity of pure condensing units in China is generally about 50% of the rated capacity, and the peak shaving capacity of typical extraction condensing units during the heating period is only about 20% of the rated capacity. The slow load response speed is a potential factor restricting the flexible operation of thermal power units. For thermal power units, the energy generation and conversion process is relatively complex, and the system heat exchange equipment has strong thermal inertia, resulting in a large time delay between commands and responses.

[0004] Therefore, there is an urgent need for a molten salt-assisted high-temperature hot water tank energy storage and peak shaving system for thermal power units to solve the above technical problems. Summary of the Invention

[0005] The purpose of the present invention is to solve the problem of the large time delay between commands and responses of thermal power units, and provide a molten salt-assisted high-temperature hot water tank energy storage and peak shaving system for thermal power units.

[0006] The present invention provides a molten salt-assisted high-temperature hot water tank energy storage and peak shaving system, including a unit power generation system and a heat storage system; the heat storage system includes a water storage tank, a pressure reducer, a bubbling chamber, a low-temperature molten salt storage tank, a high-temperature molten salt storage tank, and a heat exchanger; the power generation cycle system includes a boiler.

[0007] The first steam outlet end of the boiler is connected to the steam inlet end of the molten salt-steam heat exchanger through a pipeline via a first control valve, and the second steam outlet end is connected to the steam inlet end of the superheater through a pipeline; one path of the molten salt-steam heat exchanger is connected to the water storage tank after being connected in parallel with the pressure reducer branch through a second three-way valve and a first three-way valve, another path is connected to the low-temperature molten salt storage tank through a first pump, and still another path is connected to the high-temperature molten salt storage tank through a second pump; the first water inlet end of the water storage tank is connected to a makeup water system.

[0008] Furthermore, the bubbling chamber is located inside the water storage tank and is connected to the steam pipeline of the water storage tank, and is used for transporting the steam output by the heat exchanger to the inside of the water storage tank.

[0009] Furthermore, the unit power generation system further includes: a deaerator, a condenser, a high-pressure cylinder, an intermediate-pressure cylinder, a low-pressure cylinder, a high-pressure heat exchanger, a low-pressure heat exchanger, and a generator.

[0010] The high-pressure cylinder, the intermediate-pressure cylinder, and the low-pressure cylinder are connected by a rotating shaft drive and jointly drive a generator to output electric power to the outside; the steam extraction outlet end of the high-pressure cylinder is connected to the steam inlet end of the high-pressure heat exchanger through a pipeline; the steam extraction outlet end of the intermediate-pressure cylinder is connected to the steam inlet of the deaerator through a pipeline; the steam extraction outlet end of the low-pressure cylinder is connected to the steam inlet end of the low-pressure heat exchanger, and the steam outlet end of the low-pressure cylinder is connected to the steam inlet end of the condenser; the water outlet end of the condenser is connected to the water inlet end of the low-pressure heat exchanger through a condensate pump and a pipeline; the water outlet end of the low-pressure heat exchanger is connected to the water inlet end of the deaerator through a pipeline; the water outlet end of the deaerator is connected to the water inlet end of the high-pressure heat exchanger through a feed water pump; the feed water outlet end of the high-pressure heat exchanger is connected to the feed water inlet end of the boiler through a feed water pipeline.

[0011] Furthermore, a branch of the feed water pipeline is connected to the second feed water inlet end of the water storage tank through a second control valve.

[0012] The present invention also provides a control method for a molten salt-assisted high-temperature hot water tank energy storage and peak shaving system, as follows:

[0013] (1) When the unit operates at a low load, the heat storage system needs to store energy; close the third control valve of the heat storage system and open the first control valve; input the excess steam in the boiler into the molten salt-steam heat exchanger; start the first pump to extract low-temperature molten salt from the low-temperature molten salt storage tank into the molten salt-steam heat exchanger, and exchange heat with the steam in the molten salt-steam heat exchanger. After heat exchange, the low-temperature molten salt is heated into high-temperature molten salt and input into the high-temperature molten salt storage tank for storage; switch the first three-way valve and the second three-way valve to the steam pipeline, and the steam after heat exchange enters the bubbling chamber inside the water storage tank through the steam pipeline; the steam enters the water storage tank through the bubbling chamber and exchanges heat with water to jointly become high-temperature hot water, completing energy storage;

[0014] (2) When the unit increases the load rate, the heat storage system needs to release energy; close the first control valve of the heat storage system and open the third control valve; switch the first three-way valve and the second three-way valve to the pipeline of the pressure reducer branch, and the high-temperature hot water in the water storage tank becomes saturated steam through the pressure reducer and enters the molten salt-steam heat exchanger; start the second pump to extract high-temperature molten salt from the high-temperature molten salt storage tank into the molten salt-steam heat exchanger, and exchange heat with the saturated steam in the molten salt-steam heat exchanger. After heat exchange, the high-temperature molten salt is cooled to low-temperature molten salt and input into the low-temperature molten salt storage tank for storage; the saturated steam absorbs heat in the molten salt-steam heat exchanger and becomes superheated steam, and enters the intermediate-pressure cylinder through the pipeline where the third control valve is located to expand and do work, for energy release.

[0015] Furthermore, when energy needs to be stored, if the water capacity in the water storage tank is insufficient, start the water replenishment system or open the second control valve to supplement hot water through the branch of the feed water pipeline.

[0016] The beneficial effects of the present invention are as follows:

[0017] (1) A molten salt-assisted high-temperature hot water tank energy storage and peak shaving system provided by the present invention introduces a molten salt-assisted energy storage part; when the unit operates at low load, the steam generated by the boiler first exchanges heat with the low-temperature molten salt from the low-temperature molten salt storage tank through a low-temperature heat exchanger, and then exchanges heat with the atmospheric pressure water in the water storage tank in a bubbling manner to be jointly converted into high-temperature and high-pressure hot water. In this way, most of the heat of the steam generated by the boiler is stored in the high-temperature hot water tank, and the remaining heat exchanges heat with the low-temperature molten salt through the low-temperature heat exchanger to store the remaining heat in the high-temperature molten salt. When the unit needs to release energy during high-load operation, the high-temperature and high-pressure hot water stored in the water storage tank is decompressed by a pressure reducer to be converted into saturated steam, enters the high-temperature heat exchanger to further exchange heat with the high-temperature molten salt from the high-temperature molten salt storage tank to reach the superheated steam state, and is introduced into the intermediate pressure cylinder of the steam turbine to expand and do work.

[0018] (2) A molten salt-assisted high-temperature hot water tank energy storage and peak shaving system provided by the present invention, when releasing energy, further exchanges heat with the high-temperature molten salt through the mixed gas of the decompressed saturated steam and wet steam to reach the superheated steam state, avoiding the influence of the wet steam mixed during flashing on the corrosion of the steam turbine blades when the existing high-temperature hot water tank energy storage system releases energy. At the same time, the high-temperature hot water is decompressed to saturated steam by a pressure reducer, saving equipment costs compared with the existing molten salt storage tank energy storage system that converts hot water into steam through a heat exchanger or a steam generator.

[0019] (3) A molten salt-assisted high-temperature hot water tank energy storage and peak shaving system provided by the present invention reduces the usage amount of molten salt compared with the existing molten salt storage tank energy storage system, reduces the construction cost of the energy storage system, and improves the economy of the unit.

[0020] (4) A molten salt-assisted high-temperature hot water tank energy storage and peak shaving system provided by the present invention, the water supply of the water storage tank can also come from the water outlet end of the high-pressure heat exchanger, improving the load-changing ability of the unit.

[0021] (5) A molten salt-assisted high-temperature hot water tank energy storage and peak shaving system provided by the present invention first uses molten salt to store heat and lock high-grade thermal energy, and then uses hot water to store medium- and low-grade thermal energy. When the system needs to release energy, the hot water is flashed into saturated steam, and the high-grade thermal energy stored in the molten salt is used to heat it into superheated steam and delivered to the steam turbine to expand and do work. The cascade cooperation of the two not only retains the power generation efficiency during the deep peak shaving of the thermal power unit, but also endows the system with the agile characteristics of flexibly adapting to the fluctuations of the power market, significantly improving the overall thermodynamic efficiency of the system and the working efficiency of the steam turbine. Brief Description of the Drawings

[0022] Figure 1 is a schematic diagram of the molten salt-assisted high-temperature hot water tank energy storage and peak shaving system of the present invention;

[0023] Figure 2 This is a schematic diagram of the energy storage part of the molten salt-assisted high-temperature hot water tank energy storage and peak shaving system for storing energy in the present invention;

[0024] Figure 3 This is a schematic diagram of the energy release part of the molten salt-assisted high-temperature hot water tank energy storage and peak shaving system for releasing energy in the present invention.

[0025] The reference numerals are: 2 water replenishing system, 3 high-temperature hot water storage tank, 4 pressure reducer, 5 deaerator, 8 condenser, 9 generator, 10 bubbling chamber, 11 boiler, 12 superheater, 13 high-pressure cylinder, 14 intermediate-pressure cylinder, 15 low-pressure cylinder, 21 low-temperature molten salt storage tank, 22 high-temperature molten salt storage tank, 61 high-pressure heat exchanger, 62 low-pressure heat exchanger, 63 molten salt-steam heat exchanger, 71 feed water pump, 72 condensate pump, 73 first pump, 74 second pump, 81 first three-way valve, 82 second three-way valve, 83 first control valve, 84 second control valve, 85 third control valve. Detailed implementation manners

[0026] The present invention will be further described below with reference to the accompanying drawings.

[0027] As Figure 1 shown, the present invention provides a molten salt-assisted high-temperature hot water tank energy storage and peak shaving system, including a power generation cycle system and a heat storage system;

[0028] Figure 1 Among them, the power generation cycle system includes a deaerator 5, a condenser 8, a generator 9, a boiler 11, a superheater 12, a high-pressure cylinder 13, an intermediate-pressure cylinder 14, a low-pressure cylinder 15, a high-pressure heat exchanger 61, a low-pressure heat exchanger 62, a feed water pump 71 and a condensate pump 72; the heat storage system includes: a water replenishing system 2, a water storage tank 3, a pressure reducer 4, a bubbling chamber 10, a low-temperature molten salt storage tank 21, a high-temperature molten salt storage tank 22, a molten salt-steam heat exchanger 63, a first pump 73, a second pump 74, a first three-way valve 81, a second three-way valve 82, a first control valve 83, a second control valve 84, a third control valve 85.

[0029] The first branch of the molten salt-steam heat exchanger 63 is respectively connected to the boiler 11 and the intermediate-pressure cylinder 14 through pipelines, and control valves are installed in the pipelines.

[0030] The second branch and the third branch of the molten salt-steam heat exchanger 63 are respectively connected to the low-temperature molten salt storage tank 21 and the high-temperature molten salt storage tank 22 through pipelines for heat exchange treatment of the molten salt.

[0031] The fourth branch of the molten salt-steam heat exchanger 63 is connected to the water storage tank 3 through a pipeline via a three-way valve. The branch pipeline of the pressure reducer 4 is installed in parallel with the three-way valve. The branch of the pressure reducer is used to turn the warm and hot water in the water storage tank 3 into saturated steam and enter the molten salt-steam heat exchanger 63. The bubbling chamber 10 is placed inside the water storage tank 3 and is connected to the pipelines of the molten salt-steam heat exchanger 63 and the water storage tank 3, and is used to transport the steam in the molten salt-steam heat exchanger 63 to the inside of the water storage tank 3. The water replenishing system 2 is connected to the water storage tank 3 and is used to supply water to the water storage tank.

[0032] The high-pressure cylinder 13, the intermediate-pressure cylinder 14, the low-pressure cylinder 15 and the generator are sequentially connected in transmission. The main steam outlet end of the boiler 11 is connected to the steam inlet end of the high-pressure cylinder 13 through the superheater 12 via a pipeline. The extraction steam outlet end of the high-pressure cylinder 13 is connected to the steam inlet end of the high-pressure heat exchanger 61 through a pipeline. The extraction steam of the intermediate-pressure cylinder 14 is connected to the steam inlet end of the deaerator 5 through a pipeline. The extraction steam outlet end of the low-pressure cylinder 15 is connected to the steam inlet end of the low-pressure heat exchanger 62 through a pipeline. The steam outlet end of the low-pressure cylinder 15 is connected to the condenser 8. The condensate outlet end of the condenser 8 is connected to the condensate inlet end of the low-pressure heat exchanger 62 through the condensate pump 72. The condensate outlet end of the low-pressure heat exchanger 62 is connected to the feed water inlet end of the deaerator 5. The feed water outlet end of the deaerator 5 is connected to the feed water inlet end of the high-pressure heat exchanger 61 through the feed water pump 71. The feed water outlet end of the high-pressure heat exchanger 61 is connected to the boiler 11 through a feed water pipeline.

[0033] A molten salt-assisted high-temperature hot water tank energy storage and peak shaving system includes the following two operating modes:

[0034] During energy storage, the unit operates at low load. Excess steam is extracted from the outlet of the boiler 11 and enters the molten salt-steam heat exchanger 63 to exchange heat with the molten salt from the low-temperature molten salt storage tank 21, heating the molten salt to a high temperature state and storing it in the high-temperature molten salt storage tank 23. The exchanged steam enters the bubbling chamber 10 inside the water storage tank 3 and exchanges heat with the water in the water storage tank 3 to jointly become high-temperature hot water, completing energy storage. Among them, according to the water storage volume in the water storage tank, water is replenished by the water replenishing system as needed.

[0035] During energy release, the unit operates at high load. The high-temperature hot water in the water storage tank 3 becomes saturated steam through the pressure reducer 4 and enters the molten salt-steam heat exchanger 63, further exchanges heat with the molten salt from the high-temperature molten salt storage tank 22 to reach the superheated steam state, and enters the intermediate-pressure cylinder 14 of the steam turbine to expand and do work for energy release.

[0036] Embodiment 1

[0037] A molten salt-assisted high-temperature hot water tank energy storage and peak shaving system includes a power generation cycle system and a heat storage system;

[0038] Power generation cycle system, including a boiler device, a steam turbine, a deaerator 5, a condenser 8 and a heat exchanger; the boiler device includes a boiler 11 and a superheater 12; the steam turbine includes a high-pressure cylinder 13, an intermediate-pressure cylinder 14 and a low-pressure cylinder 15 of the steam turbine; the heat exchanger includes a high-pressure heat exchanger 61 and a low-pressure heat exchanger 62; wherein, the superheater 12 is connected to the high-pressure cylinder 13 of the steam turbine, the high-pressure cylinder 13 of the steam turbine is respectively connected to the high-pressure heat exchanger 61 and the intermediate-pressure cylinder 14 of the steam turbine, the intermediate-pressure cylinder 14 of the steam turbine is respectively connected to the deaerator 5 and the low-pressure cylinder 15 of the steam turbine, the low-pressure cylinder 15 of the steam turbine is respectively connected to the low-pressure heat exchanger 62 and the condenser 8, the deaerator 5 is respectively connected to the high-pressure heat exchanger 61 and the low-pressure heat exchanger 62, the low-pressure heat exchanger 62 and the condenser 8 are connected by a condensate pump 72, and a generator 9 is arranged on one side of the low-pressure cylinder 15 of the steam turbine and is connected to the low-pressure cylinder 15 of the steam turbine through a rotating shaft;

[0039] The energy storage part of the heat storage system, such as Figure 2 shown, includes a water replenishing system 2, a water storage tank 3, a low-temperature molten salt storage tank 21, a high-temperature molten salt storage tank 22, a molten salt-steam heat exchanger 63, a first pump 73, a second pump 74, a first three-way valve 81, a second three-way valve 82, a first control valve 83, a second control valve 84, and a third control valve 85. The inlet end of the water storage tank 3 has three branches. The first branch is connected to the outlet end of the water replenishing system 2, the second branch is connected to the pipeline branch of the high-pressure heat exchanger 61 and the boiler 11, and the third branch is connected to the outlet end of the molten salt-steam heat exchanger 63; the inlet end of the molten salt-steam heat exchanger 63 has two branches. The first branch is connected to the steam outlet end generated by the boiler 11, and the second branch is connected to the outlet end of the low-temperature molten salt storage tank 21 through the first pump 73. The outlet end has two branches. The first branch is connected to the inlet end of the high-temperature molten salt storage tank 22, and the second is connected to the inlet end of the water storage tank 3. The bubbling chamber 10 is placed inside the water storage tank 3 and is connected to the outlet end of the low-temperature heat exchanger 64.

[0040] The energy release part, such as Figure 3 shown, includes a high-temperature hot water tank 3, a pressure reducer 4, a high-temperature molten salt storage tank 22, a low-temperature molten salt storage tank 21, and a molten salt-steam heat exchanger 63. The outlet end of the high-temperature hot water tank 3 is connected to the inlet end of the pressure reducer 4. The inlet end of the molten salt-steam heat exchanger 63 has two branches. The first branch is connected to the outlet end of the high-temperature molten salt storage tank 22 through the second pump 74, and the second branch is connected to the outlet end of the pressure reducer 4. The outlet end of the molten salt-steam heat exchanger 63 has two branches. The first branch is connected to the inlet end of the low-temperature molten salt storage tank 21, and the second branch is connected to the inlet end of the intermediate-pressure cylinder 14 of the steam turbine.

[0041] The working principle and working process of this embodiment are as follows:

[0042] When the unit operates at low load, the heat storage system needs to store energy; close the third control valve 85; open the first control valve 83, and the excess steam in the boiler 11 flows to the molten salt-steam heat exchanger 63; start the first pump 73 to draw low-temperature molten salt from the low-temperature molten salt storage tank 21 to the molten salt-steam heat exchanger 63 for heat exchange with steam. After heat exchange, the low-temperature molten salt is heated into high-temperature molten salt and flows to the high-temperature molten salt storage tank 22 for storage; switch the first three-way valve 81 and the second three-way valve 82 to the main pipeline. The steam after heat exchange directly enters the bubbling chamber 10 inside the water storage tank 3 through the main pipeline, and fully exchanges heat with the water in the water storage tank 3 to jointly become high-temperature hot water, completing energy storage. If the water in the water storage tank 3 is insufficient, start the water replenishment system 2 or open the second control valve 84 to supplement the hot water from the outlet pipeline of the high-pressure heat exchanger 61.

[0043] When the unit quickly increases the load rate, the heat storage system needs to release energy; close the first control valve 83 and open the third control valve 85; switch the first three-way valve 81 and the second three-way valve 82 to the pipeline where the pressure reducer 4 is located. The high-temperature hot water in the high-temperature hot water tank 3 becomes saturated steam through the pressure reducer 4 and enters the molten salt-steam heat exchanger 63; start the second pump 74 to draw high-temperature molten salt from the high-temperature molten salt storage tank 22 to the molten salt-steam heat exchanger 63 for heat exchange with the saturated steam. After heat exchange, the high-temperature molten salt is cooled to low-temperature molten salt and flows to the low-temperature molten salt storage tank 21 for storage; the saturated steam absorbs heat in the molten salt-steam heat exchanger 63 and becomes superheated steam, and enters the intermediate pressure cylinder 14 of the steam turbine through the pipeline where the third control valve 85 is located to expand and do work, releasing energy.

[0044] In summary, when the unit operates at low load, the system can store all the heat carried by the steam in the water storage tank 3 and the high-temperature molten salt storage tank 22; during the deep regulation of the unit, the system can quickly increase the load or improve the peak load capacity. Open the pressure reducer 4 to reduce the pressure of the high-temperature hot water in the water storage tank 3 into saturated steam, and then heat it to superheated steam state by exchanging heat with the high-temperature molten salt, enter the intermediate pressure cylinder 14 to expand and do work, and then merge with the exhaust steam of the intermediate pressure cylinder 14 and enter the low-pressure cylinder 15 to expand and generate electricity, improving the quick load-changing ability and peak load capacity of the unit.

[0045] It should be noted that in the description of the present disclosure, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of the present disclosure, unless otherwise specified, the meaning of "plurality" is two or more.

[0046] Any process or method description depicted in the flowchart or otherwise described herein can be understood to represent a module, segment, or portion of code including one or more executable instructions for implementing a specific logical function or process. The scope of the preferred embodiments of the present disclosure includes additional implementations where functions may be executed in a substantially simultaneous manner or in the reverse order according to the functions involved, rather than in the order shown or discussed, which should be understood by those skilled in the art to which the embodiments of the present disclosure pertain.

[0047] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0048] Although the embodiments of the present disclosure have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present disclosure. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present disclosure.

Claims

1. A molten salt-assisted high-temperature hot water tank energy storage and peak shaving system, characterized in that It includes a unit power generation system and a heat storage system; the heat storage system includes a water storage tank (3), a pressure reducer (4), a bubbling chamber (10), a low-temperature molten salt storage tank (21), a high-temperature molten salt storage tank (22), and a heat exchanger (63); the power generation cycle system includes a boiler (11). The first steam outlet end of the boiler (11) is connected to the steam inlet end of the molten salt-steam heat exchanger (63) through a pipeline via a first control valve (83), and the second steam outlet end is connected to the steam inlet end of the superheater (12) through a pipeline; one path of the molten salt-steam heat exchanger (63) is connected to the water storage tank (3) after being in parallel with the pressure reducer (4) branch through a second three-way valve (82) and a first three-way valve (81), another path is connected to the low-temperature molten salt storage tank (21) through a first pump (73), and still another path is connected to the high-temperature molten salt storage tank (22) through a second pump (74); the first water inlet end of the water storage tank (3) is connected to the makeup water system (2).

2. The molten salt-assisted high-temperature hot water tank energy storage and peak shaving system according to claim 1, wherein The bubbling chamber (10) is located inside the water storage tank (3) and is connected to the steam pipeline of the water storage tank (3) for transporting the steam output by the heat exchanger (63) to the inside of the water storage tank (3).

3. The molten salt-assisted high-temperature hot water tank energy storage and peak shaving system according to claim 2, wherein, The unit power generation system further includes: a deaerator (5), a condenser (8), a high-pressure cylinder (13), a low-pressure cylinder (15), a high-pressure heat exchanger (61), a low-pressure heat exchanger (62), and a generator (9). The high-pressure cylinder (13), the intermediate-pressure cylinder (14), and the low-pressure cylinder (15) are connected by a rotating shaft for transmission and jointly drive the generator (9) to output electric power externally; the extraction steam outlet end of the high-pressure cylinder (13) is connected to the steam inlet end of the high-pressure heat exchanger (61) through a pipeline; the extraction steam outlet end of the intermediate-pressure cylinder (14) is connected to the steam inlet of the deaerator (5) through a pipeline; the extraction steam outlet end of the low-pressure cylinder (15) is connected to the steam inlet end of the low-pressure heat exchanger (62), and the steam outlet end of the low-pressure cylinder (15) is connected to the steam inlet end of the condenser (8); the water outlet end of the condenser (8) is connected to the water inlet end of the low-pressure heat exchanger (62) through a condensate pump (72) by a pipeline; the water outlet end of the low-pressure heat exchanger (62) is connected to the water inlet end of the deaerator (5) through a pipeline; the water outlet end of the deaerator (5) is connected to the water inlet end of the high-pressure heat exchanger (61) through a feed water pump (71); the feed water outlet end of the high-pressure heat exchanger (61) is connected to the feed water inlet end of the boiler (11) through a feed water pipeline.

4. The molten salt-assisted high-temperature hot water tank energy storage and peak shaving system according to claim 3, wherein A branch of the feed water pipeline is connected to the second water inlet end of the water storage tank (3) through a second control valve (84).

5. A control method for a molten salt-assisted high-temperature hot water tank energy storage and peak shaving system as described in claim 4, characterized in that, As follows: (1) When the unit operates at low load, the heat storage system needs to store energy; close the third control valve (85) of the heat storage system and open the first control valve (83); input the surplus steam in the boiler (11) into the molten salt-steam heat exchanger (63); start the first pump (73) to extract low-temperature molten salt from the low-temperature molten salt storage tank (21) into the molten salt-steam heat exchanger (63) to exchange heat with the steam in the molten salt-steam heat exchanger (63). After heat exchange, the low-temperature molten salt is heated into high-temperature molten salt and input into the high-temperature molten salt storage tank (22) for storage; switch the first three-way valve (81) and the second three-way valve (82) to the steam pipeline, and the steam after heat exchange enters the bubbling chamber (10) inside the water storage tank (3) through the steam pipeline; the steam enters the water storage tank (3) through the bubbling chamber (10) and exchanges heat with water to jointly become high-temperature hot water, completing energy storage. (2) When the unit increases the load rate, the heat storage system needs to release energy; close the first control valve (83) of the heat storage system and open the third control valve (85); switch the first three-way valve (81) and the second three-way valve (82) to the pipeline of the pressure reducer (4) branch. The high-temperature hot water in the water storage tank (3) becomes saturated steam through the pressure reducer (4) and enters the molten salt-steam heat exchanger (63); start the second pump (74) to extract high-temperature molten salt from the high-temperature molten salt storage tank (22) into the molten salt-steam heat exchanger (63) to exchange heat with the saturated steam in the molten salt-steam heat exchanger (63). After heat exchange, the high-temperature molten salt is cooled to low-temperature molten salt and input into the low-temperature molten salt storage tank (21) for storage; the saturated steam absorbs heat in the molten salt-steam heat exchanger (63) and becomes superheated steam, and enters the intermediate pressure cylinder (14) through the pipeline where the third control valve (85) is located to expand and do work, releasing energy.

6. The control method of the molten salt-assisted high-temperature hot water tank energy storage and peak shaving system according to claim 5, characterized in that, When energy storage is required, if the water capacity in the water storage tank (3) is insufficient, start the water replenishing system (2) or open the second control valve (84) to supplement hot water from the branch of the water supply pipeline.

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