Temperature zone matching series-parallel compression and steam turbine side high-pressure heater removal energy storage system and method

Abstract

The invention discloses a temperature zone matching series-parallel compression and steam turbine side high-pressure heater removal energy storage system which comprises a Brayton heat pump circulation unit, the Brayton heat pump circulation unit comprises a first-stage compressor, a second-stage compressor, an air-molten salt heat exchanger set and an air-air heat exchanger set, the air-air heat exchanger set is connected with an expansion machine, and the expansion machine is connected with a heat exchanger. The air-molten salt heat exchanger set is sequentially connected with a double-salt multi-tank heat storage unit, a steam Rankine cycle unit and a generator. The invention further discloses a control method of the system. The structure of an existing Carnot battery system is modified, redundant electricity is converted into heat to be stored in the power grid power supply trough, the stored heat is converted into electricity to be released in the power grid power supply peak, heat is supplied to a high-pressure heater and a preheater, multi-stage compression parallel connection change is conducted on heat storage of the heat pump side in a matched mode, the overall system efficiency is improved, and the energy consumption is reduced. And proportional adjustment of high-temperature heat and low-temperature heat is facilitated.

Description

Technical Field

[0001] The invention relates to an energy storage system and method for temperature zone matching series-parallel compression and turbine side high-pressure heater removal, belonging to the technical field of energy storage. Background Art

[0002] As a representative of electric-thermal-electric energy storage technology, the Carnot Battery achieves flexible conversion of electric and thermal energy through molten salt heat storage. However, the existing system still has significant defects in temperature zone matching, compression efficiency, and coordination with thermal power units.

[0003] Poor temperature zone adaptability: The heat storage requirements of the high temperature section and the medium and low temperature sections are difficult to achieve through a single compression cycle, resulting in significant temperature difference losses in the molten salt heat storage system.

[0004] Insufficient flexibility of the compression system: Traditional series compression or parallel compression technology cannot dynamically match grid load fluctuations, especially under partial load, the compressor energy efficiency drops significantly.

[0005] Thermal power units achieve deep peak regulation by removing high-voltage heaters, but traditional solutions have the following problems:

[0006] Disruption of the thermal cycle: The removal of the high-pressure heater causes a sudden drop in the feed water temperature, requiring additional post-firing or electric heating to maintain steam parameters, increasing carbon emissions and energy consumption.

[0007] Lack of synergy in molten salt heat storage: The existing molten salt heat storage system is not deeply coupled with the waste heat recovery after the high-pressure heater is removed, resulting in the inability to cascade the utilization of medium and low temperature waste heat.

[0008] Dynamic response defects of molten salt thermal storage system

[0009] Although molten salt thermal storage has the advantage of high energy storage density, its dynamic matching with the compression / expansion system still has problems:

[0010] Low multi-stage heat exchange efficiency: The traditional single-tank heat storage structure cannot achieve temperature stratification of molten salt in a wide temperature range, resulting in a sharp increase in stress in the heat exchanger material and loss of heat transfer temperature difference.

[0011] Control strategy lag: The existing system relies on fixed-priority charging and discharging logic, and is unable to dynamically adjust the compression mode and heat storage path based on the real-time grid electricity price, waste heat fluctuations, and molten salt temperature zone status. Summary of the Invention

[0012] The purpose of the present invention is to provide an energy storage system with temperature zone matching series-parallel compression and turbine-side high-pressure heater removal, and also to provide a control method for the energy storage system with temperature zone matching series-parallel compression and turbine-side high-pressure heater removal. The present invention transforms the structure of the existing Carnot battery system to convert excess electricity into heat storage during grid power supply troughs, and to convert the stored heat into electricity and release it during grid power supply peaks to heat the high-pressure heater and preheater. In conjunction with the multi-stage compression and parallel changes of the heat storage on the heat pump side, the overall system efficiency is increased, which is more conducive to the regulation of the high-temperature heat and low-temperature heat ratio.

[0013] To solve the above technical problems, the present invention adopts the following technical solution: an energy storage system with temperature zone matching series-parallel compression and steam turbine side high-pressure heater removal, including a Brayton heat pump circulation unit, the Brayton heat pump circulation unit including a first-stage compressor, a second-stage compressor, an air-molten salt heat exchanger group and an air-air heat exchanger group, the air-air heat exchanger group is connected to an expander, and the air-molten salt heat exchanger group is sequentially connected to a dual-salt multi-tank heat storage unit, a steam Rankine cycle unit and a generator.

[0014] The aforementioned temperature zone matching series-parallel compression and steam turbine side high-pressure heater removal energy storage system, the air-molten salt heat exchanger group is provided with at least five sets, the air-molten salt heat exchanger group includes air-molten salt heat exchanger A, air-molten salt heat exchanger B, air-molten salt heat exchanger C, air-molten salt heat exchanger D, air-molten salt heat exchanger E, air-molten salt heat exchanger A is connected to air-molten salt heat exchanger B in sequence and is arranged between the first compressor and the second compressor, the second compressor is connected to air-molten salt heat exchanger C, air-molten salt heat exchanger D, air-molten salt heat exchanger E, and air-molten salt heat exchanger B is connected to the air-air heat exchanger group.

[0015] The aforementioned temperature zone matching series-parallel compression and steam turbine side high-pressure heater removal energy storage system, the dual-salt multi-tank heat storage unit includes a solar salt molten salt high-temperature heat storage tank, a solar salt molten salt low-temperature heat storage tank, a Hitec salt molten salt high-temperature heat storage tank, a Hitec salt molten salt medium-temperature heat storage tank and a Hitec salt molten salt low-temperature heat storage tank. The solar salt molten salt high-temperature heat storage tank, the solar salt molten salt low-temperature heat storage tank, the Hitec salt molten salt high-temperature heat storage tank, the Hitec salt molten salt medium-temperature heat storage tank and the Hitec salt molten salt low-temperature heat storage tank are all connected to the steam Rankine cycle unit, the C air-molten salt heat exchanger is respectively connected to the solar salt molten salt high-temperature heat storage tank and the solar salt molten salt low-temperature heat storage tank, the D air-molten salt heat exchanger is respectively connected to the Hitec salt molten salt high-temperature heat storage tank and the Hitec salt molten salt medium-temperature heat storage tank, and the E air-molten salt heat exchanger is respectively connected to the Hitec salt molten salt medium-temperature heat storage tank and the Hitec salt molten salt low-temperature heat storage tank.

[0016] The aforementioned temperature zone matching series-parallel compression and turbine side high-pressure heater removal energy storage system, the steam Rankine cycle unit includes a multi-stage steam turbine unit, a superheater, an evaporator, a preheater, and a reheater connected in sequence, the superheater is respectively connected to the solar salt molten salt high-temperature heat storage tank and the solar salt molten salt low-temperature heat storage tank, the evaporator is respectively connected to the Hitec salt molten salt high-temperature heat storage tank and the Hitec salt molten salt medium-temperature heat storage tank, the preheater is respectively connected to the Hitec salt molten salt medium-temperature heat storage tank and the Hitec salt molten salt low-temperature heat storage tank, and the reheater is respectively connected to the solar salt molten salt high-temperature heat storage tank and the solar salt molten salt low-temperature heat storage tank.

[0017] The aforementioned temperature zone matching series-parallel compression and turbine side high-pressure heater removal energy storage system, the multi-stage steam turbine unit includes a steam turbine high-pressure cylinder, a steam turbine intermediate-pressure cylinder, and a steam turbine low-pressure cylinder connected in sequence, a low-pressure heater group is connected to the steam turbine low-pressure cylinder, a superheater is connected to the steam turbine high-pressure cylinder, a reheater is respectively connected to the steam turbine high-pressure cylinder and the steam turbine intermediate-pressure cylinder, and a preheater is connected to the steam turbine intermediate-pressure cylinder.

[0018] The aforementioned temperature zone matches the energy storage system of series-parallel compression and turbine side high-pressure heater removal. A deaerator is provided between the turbine intermediate pressure cylinder and the preheater, and the deaerator is also connected to the low-pressure heater group.

[0019] The aforementioned temperature zone matches the energy storage system of series-parallel compression and turbine side high-pressure heater removal. The low-pressure cylinder of the steam turbine is connected to a condenser, which is also connected to the low-pressure heater group.

[0020] The control method of the energy storage system for the aforementioned temperature zone matching series-parallel compression and turbine side high pressure heater removal is as follows:

[0021] When the power consumption of the power grid is low, the heat pump side passage and the heat exchange passage between the molten salt side and the heat pump side are opened at the same time. The Brayton heat pump circulation unit uses low-cost electricity to act on the first-stage compressor and the second-stage compressor, so that the first-stage compressor and the second-stage compressor work to pressurize the low-temperature and low-pressure air into high-pressure and high-temperature gas. Then, the air is processed by heat exchange, and the high-temperature heat is stored in the solar salt molten salt high-temperature heat storage tank and the solar salt molten salt low-temperature heat storage tank, and the low-temperature heat is stored in the Hitec salt molten salt high-temperature heat storage tank, the Hitec salt molten salt medium-temperature heat storage tank and the Hitec salt molten salt low-temperature heat storage tank. After expansion and environmental heating, the heat enters the first-stage compressor and the second-stage compressor for circulation. At this time, the coal-fired power generation unit stops working;

[0022] During peak power consumption in the power grid, the turbine side passage and the heat exchange passages between the molten salt side and the heat pump side are opened at the same time. Heat is released through the molten salt, and steam is used to pass through the superheater, reheater, evaporator, and preheater to heat the working fluid in the steam Rankine cycle unit, so that the turbine works to generate electricity. At this time, the Brayton heat pump cycle unit stops working.

[0023] The control method of the energy storage system for the aforementioned temperature zone matching series-parallel compression and turbine side high pressure heater removal is as follows:

[0024] When the Brayton heat pump circulation unit is working, the air is split after passing through the first-stage compressor, and part of the air passes through the hot side of the A air-molten salt heat exchanger and the Hitec salt molten salt high-temperature heat storage tank and the B air-molten salt heat exchanger and the Hitec salt molten salt medium-temperature heat storage tank in sequence, and part of the air enters the secondary compressor, and then the air passes through the C air-molten salt heat exchanger and the solar salt molten salt high-temperature heat storage tank, the solar salt molten salt low-temperature heat storage tank in sequence. The hot side of the D air-molten salt heat exchanger and the Hitec salt molten salt high-temperature heat storage tank and the E air-molten salt heat exchanger and the Hitec salt molten salt medium-temperature heat storage tank, the Hitec salt molten salt low-temperature heat storage tank, and then enter the hot side of the air-air heat exchanger group respectively and are connected to the expander inlet for expansion turbine expansion.

[0025] When the steam Rankine cycle unit is working, the steam comes out of the superheater and passes through the high-pressure cylinder of the steam turbine, the intermediate-pressure cylinder of the steam turbine, and the low-pressure cylinder of the steam turbine in sequence to generate electricity. The steam coming out of the high-pressure cylinder of the steam turbine passes through the reheater, and part of it is transported to the intermediate-pressure cylinder of the steam turbine, and the other part enters the low-pressure cylinder of the steam turbine. After doing work, it passes through the condenser and the low-pressure heater group and then enters the deaerator. After passing through the deaerator, it enters the preheater, evaporator, and superheater in sequence to exchange heat with the dual-salt multi-tank heat storage unit;

[0026] When the dual-salt multi-tank heat storage unit is working, the air comes out from the cold side of the heat exchange between the A air-molten salt heat exchanger and the solar salt molten salt high-temperature heat storage tank, and then stores heat in the solar salt molten salt high-temperature heat storage tank. At peak times, the air passes through the superheater and the reheater, releases the stored heat into the steam Rankine cycle unit, and then enters the solar salt molten salt low-temperature heat storage tank; the air comes out from the cold side of the heat exchange between the D air-molten salt heat exchanger and the Hitec salt molten salt high-temperature heat storage tank, and then stores heat in the Hitec salt molten salt high-temperature heat storage tank. At peak times, the air passes through the evaporator, releases the stored heat into the steam Rankine cycle unit, and then enters the Hitec salt molten salt medium-temperature heat storage tank; the air comes out from the cold side of the heat exchange between the E air-molten salt heat exchanger and the Hitec salt molten salt medium-temperature heat storage tank, and then stores heat in the Hitec salt molten salt medium-temperature heat storage tank. At peak times, the air passes through the evaporator, releases the stored heat into the steam Rankine cycle unit, and then enters the Hitec salt molten salt low-temperature heat storage tank.

[0027] Compared with the prior art, the present invention is beneficial in that:

[0028] 1. The present invention removes the high-pressure heater from a coal-fired power plant. This allows for the replacement of existing, older power plants with charging and heat storage units, while shutting down all high-pressure heaters. This reduces costs for retrofitting older power plants while offering certain location advantages, including a smaller footprint and higher heat density. Removing the high-pressure heater expands the heat storage temperature zone on the heat pump side, allowing for better utilization of the low-temperature heat from the Brayton heat pump cycle, resulting in higher efficiency. While the efficiency of the steam Rankine cycle is reduced, the overall system efficiency is increased, resulting in improved system performance.

[0029] 2. The heat storage system of the present invention adopts dual salt species and dual molten salt storage tanks of solar salt molten salt and Hitec molten salt, which expands the temperature range of heat storage, better matches the high-temperature heat and low-temperature heat generated by the heat pump side, and has higher heat storage efficiency.

[0030] 3. The heat pump side of the present invention uses a multi-stage compression series-parallel method to convert electricity into heat, which not only increases the efficiency of the Brayton heat pump cycle, but also makes it easier to adjust the ratio of high-temperature heat and low-temperature heat in the entire process. By adjusting the ratio of the first-stage compressor outlet diverter, the heat in the double molten salt storage tanks can be adjusted, which is better matched with the old generator set. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural schematic diagram of the present invention;

[0032] Figure 2 This is a diagram of the connection relationship between the Brayton heat pump circulation unit, the dual-salt multi-tank heat storage unit, the steam Rankine cycle unit, and the generator in the present invention.

[0033] Figure 1: 1-Brayton heat pump circulation unit, 2-first stage compressor, 3-second stage compressor, 4-air-molten salt heat exchanger group, 5-air-air heat exchanger group, 6-expander, 7-dual salt multi-tank heat storage unit, 8-steam Rankine cycle unit, 9-generator, 10-A air-molten salt heat exchanger, 11-B air-molten salt heat exchanger, 12-C air-molten salt heat exchanger, 13-D air-molten salt heat exchanger, 14-E air-molten salt heat exchanger, 15-solar salt melt Salt high-temperature heat storage tank, 16-solar salt molten salt low-temperature heat storage tank, 17-Hitec salt molten salt high-temperature heat storage tank, 18-Hitec salt molten salt medium-temperature heat storage tank, 19-Hitec salt molten salt low-temperature heat storage tank, 20-multi-stage steam turbine unit, 21-superheater, 22-evaporator, 23-preheater, 24-reheater, 25-turbine high-pressure cylinder, 26-turbine medium-pressure cylinder, 27-turbine low-pressure cylinder, 28-low-pressure heater group, 29-deaerator, 30-condenser.

[0034] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. DETAILED DESCRIPTION

[0035] Embodiment 1 of the present invention: An energy storage system with temperature zone matching series-parallel compression and steam turbine side high-pressure heater removal includes a Brayton heat pump circulation unit 1, wherein the Brayton heat pump circulation unit 1 includes a first-stage compressor 2, a second-stage compressor 3, an air-molten salt heat exchanger group 4 and an air-air heat exchanger group 5, the air-air heat exchanger group 5 is connected to an expander 6, and the air-molten salt heat exchanger group 4 is sequentially connected to a dual-salt multi-tank heat storage unit 7, a steam Rankine cycle unit 8 and a generator 9.

[0036] Embodiment 2 of the present invention: An energy storage system with temperature zone matching series-parallel compression and turbine side high-pressure heater removal, comprising a Brayton heat pump circulation unit 1, wherein the Brayton heat pump circulation unit 1 comprises a primary compressor 2, a secondary compressor 3, an air-molten salt heat exchanger group 4 and an air-air heat exchanger group 5, the air-air heat exchanger group 5 is connected to an expander 6, and the air-molten salt heat exchanger group 4 is sequentially connected to a dual-salt multi-tank heat storage unit 7, a steam Rankine cycle unit 8 and a generator 9; the air-molten salt heat exchanger group 4 is provided with at least five sets, and the air-molten salt heat exchanger Group 4 includes air-molten salt heat exchanger A 10, air-molten salt heat exchanger B 11, air-molten salt heat exchanger C 12, air-molten salt heat exchanger D 13, and air-molten salt heat exchanger E 14. Air-molten salt heat exchanger A 10 is connected to air-molten salt heat exchanger B 11 in sequence and is arranged between the first-stage compressor 2 and the second-stage compressor 3. The second-stage compressor 3 is connected to air-molten salt heat exchanger C 12, air-molten salt heat exchanger D 13, and air-molten salt heat exchanger E 14 in sequence. Air-molten salt heat exchanger B 11 is connected to the air-air heat exchanger group 5.

[0037] Embodiment 3 of the present invention: An energy storage system with temperature zone matching series-parallel compression and turbine side high-pressure heater removal, comprising a Brayton heat pump circulation unit 1, wherein the Brayton heat pump circulation unit 1 comprises a primary compressor 2, a secondary compressor 3, an air-molten salt heat exchanger group 4 and an air-air heat exchanger group 5, the air-air heat exchanger group 5 is connected to an expander 6, and the air-molten salt heat exchanger group 4 is sequentially connected to a dual-salt multi-tank heat storage unit 7, a steam Rankine cycle unit 8 and a generator 9; the air-molten salt heat exchanger group 4 is at least There are five sets of air-molten salt heat exchanger groups 4, including A air-molten salt heat exchanger 10, B air-molten salt heat exchanger 11, C air-molten salt heat exchanger 12, D air-molten salt heat exchanger 13, and E air-molten salt heat exchanger 14. A air-molten salt heat exchanger 10 is connected to B air-molten salt heat exchanger 11 in sequence and is arranged between the first-stage compressor 2 and the second-stage compressor 3. The second-stage compressor 3 is connected to C air-molten salt heat exchanger 12, D air-molten salt heat exchanger 13, and E air-molten salt heat exchanger 14 in sequence. 4, B air-molten salt heat exchanger 11 is connected to the air-air heat exchanger group 5; the dual salt multi-tank heat storage unit 7 includes a solar salt molten salt high temperature heat storage tank 15, a solar salt molten salt low temperature heat storage tank 16, a Hitec salt molten salt high temperature heat storage tank 17, a Hitec salt molten salt medium temperature heat storage tank 18 and a Hitec salt molten salt low temperature heat storage tank 19, a solar salt molten salt high temperature heat storage tank 15, a solar salt molten salt low temperature heat storage tank 16, a Hitec salt molten salt high temperature heat storage tank 17, a Hitec salt molten salt medium temperature heat storage tank 18 and Hitec salt molten salt low-temperature heat storage tank 19 are both connected to the steam Rankine cycle unit 8, C air-molten salt heat exchanger 12 is respectively connected to the solar salt molten salt high-temperature heat storage tank 15 and the solar salt molten salt low-temperature heat storage tank 16, D air-molten salt heat exchanger 13 is respectively connected to the Hitec salt molten salt high-temperature heat storage tank 17 and the Hitec salt molten salt medium-temperature heat storage tank 18, E air-molten salt heat exchanger 14 is respectively connected to the Hitec salt molten salt medium-temperature heat storage tank 18 and the Hitec salt molten salt low-temperature heat storage tank 19.

[0038] Embodiment 4 of the present invention: An energy storage system with temperature zone matching series-parallel compression and turbine side high-pressure heater removal, comprising a Brayton heat pump circulation unit 1, wherein the Brayton heat pump circulation unit 1 comprises a primary compressor 2, a secondary compressor 3, an air-molten salt heat exchanger group 4 and an air-air heat exchanger group 5, the air-air heat exchanger group 5 is connected to an expander 6, and the air-molten salt heat exchanger group 4 is sequentially connected to a dual-salt multi-tank heat storage unit 7, a steam Rankine cycle unit 8 and a generator 9; the air-molten salt heat exchanger group 4 is provided with at least five sets, and the air-molten salt heat exchanger group 4 comprises an air-molten salt heat exchanger A 10, an air-molten salt heat exchanger B 11, and an air-molten salt heat exchanger C 12, D air-molten salt heat exchanger 13, E air-molten salt heat exchanger 14, A air-molten salt heat exchanger 10 is sequentially connected to B air-molten salt heat exchanger 11 and is arranged between the first compressor 2 and the second compressor 3, the second compressor 3 is sequentially connected to C air-molten salt heat exchanger 12, D air-molten salt heat exchanger 13, E air-molten salt heat exchanger 14, B air-molten salt heat exchanger 11 is connected to the air-air heat exchanger group 5; the dual-salt multi-tank heat storage unit 7 includes a solar salt molten salt high-temperature heat storage tank 15, a solar salt molten salt low-temperature heat storage tank 16, a Hitec salt molten salt high-temperature heat storage tank 17, a Hitec salt molten salt medium-temperature heat storage tank 18 and a Hitec The salt molten salt low temperature heat storage tank 19, the solar salt molten salt high temperature heat storage tank 15, the solar salt molten salt low temperature heat storage tank 16, the Hitec salt molten salt high temperature heat storage tank 17, the Hitec salt molten salt medium temperature heat storage tank 18 and the Hitec salt molten salt low temperature heat storage tank 19 are all connected to the steam Rankine cycle unit 8, the C air-molten salt heat exchanger 12 is respectively connected to the solar salt molten salt high temperature heat storage tank 15, the solar salt molten salt low temperature heat storage tank 16, the D air-molten salt heat exchanger 13 is respectively connected to the Hitec salt molten salt high temperature heat storage tank 17, the Hitec salt molten salt medium temperature heat storage tank 18, the E air-molten salt heat exchanger 14 is respectively connected to the Hitec salt molten salt medium temperature heat storage tank 18, the H itec salt molten salt low-temperature heat storage tank 19; the steam Rankine cycle unit 8 includes a multi-stage steam turbine unit 20, a superheater 21, an evaporator 22, a preheater 23, and a reheater 24 connected in sequence, the superheater 21 is respectively connected to the solar salt molten salt high-temperature heat storage tank 15 and the solar salt molten salt low-temperature heat storage tank 16, the evaporator 22 is respectively connected to the Hitec salt molten salt high-temperature heat storage tank 17 and the Hitec salt molten salt medium-temperature heat storage tank 18, the preheater 23 is respectively connected to the Hitec salt molten salt medium-temperature heat storage tank 18 and the Hitec salt molten salt low-temperature heat storage tank 19, and the reheater 24 is respectively connected to the solar salt molten salt high-temperature heat storage tank 15 and the solar salt molten salt low-temperature heat storage tank 16.

[0039] Embodiment 5 of the present invention: An energy storage system with temperature zone matching series-parallel compression and turbine side high-pressure heater removal, including a Brayton heat pump circulation unit 1, the Brayton heat pump circulation unit 1 includes a first-stage compressor 2, a second-stage compressor 3, an air-molten salt heat exchanger group 4 and an air-air heat exchanger group 5, the air-air heat exchanger group 5 is connected to an expander 6, and the air-molten salt heat exchanger group 4 is sequentially connected to a dual-salt multi-tank heat storage unit 7, a steam Rankine cycle unit 8 and a generator 9; the air-molten salt heat exchanger group 4 is provided with at least five sets, and the air-molten salt heat exchanger group 4 includes an air-molten salt heat exchanger A 10, an air-molten salt heat exchanger B 11, and an air-molten salt heat exchanger C 12, D air-molten salt heat exchanger 13, E air-molten salt heat exchanger 14, A air-molten salt heat exchanger 10 is sequentially connected to B air-molten salt heat exchanger 11 and is arranged between the first compressor 2 and the second compressor 3, the second compressor 3 is sequentially connected to C air-molten salt heat exchanger 12, D air-molten salt heat exchanger 13, E air-molten salt heat exchanger 14, B air-molten salt heat exchanger 11 is connected to the air-air heat exchanger group 5; the dual-salt multi-tank heat storage unit 7 includes a solar salt molten salt high-temperature heat storage tank 15, a solar salt molten salt low-temperature heat storage tank 16, a Hitec salt molten salt high-temperature heat storage tank 17, a Hitec salt molten salt medium-temperature heat storage tank 18 and a Hitec The salt molten salt low temperature heat storage tank 19, the solar salt molten salt high temperature heat storage tank 15, the solar salt molten salt low temperature heat storage tank 16, the Hitec salt molten salt high temperature heat storage tank 17, the Hitec salt molten salt medium temperature heat storage tank 18 and the Hitec salt molten salt low temperature heat storage tank 19 are all connected to the steam Rankine cycle unit 8, the C air-molten salt heat exchanger 12 is respectively connected to the solar salt molten salt high temperature heat storage tank 15, the solar salt molten salt low temperature heat storage tank 16, the D air-molten salt heat exchanger 13 is respectively connected to the Hitec salt molten salt high temperature heat storage tank 17, the Hitec salt molten salt medium temperature heat storage tank 18, the E air-molten salt heat exchanger 14 is respectively connected to the Hitec salt molten salt medium temperature heat storage tank 18, the H itec salt molten salt low-temperature heat storage tank 19; the steam Rankine cycle unit 8 includes a multi-stage steam turbine unit 20, a superheater 21, an evaporator 22, a preheater 23, and a reheater 24 connected in sequence, the superheater 21 is respectively connected to the solar salt molten salt high-temperature heat storage tank 15 and the solar salt molten salt low-temperature heat storage tank 16, the evaporator 22 is respectively connected to the Hitec salt molten salt high-temperature heat storage tank 17 and the Hitec salt molten salt medium-temperature heat storage tank 18, the preheater 23 is respectively connected to the Hitec salt molten salt medium-temperature heat storage tank 18 and the Hitec salt molten salt low-temperature heat storage tank 19, and the reheater 24 is respectively connected to the solar salt molten salt high-temperature heat storage tank 15 and the solar salt molten salt low-temperature heat storage tank 16;The multi-stage steam turbine unit 20 includes a steam turbine high-pressure cylinder 25, a steam turbine intermediate-pressure cylinder 26, and a steam turbine low-pressure cylinder 27 connected in sequence. The low-pressure cylinder 27 is connected to a low-pressure heater unit 28. The superheater 21 is connected to the steam turbine high-pressure cylinder 25. The reheater 24 is connected to the steam turbine high-pressure cylinder 25 and the steam turbine intermediate-pressure cylinder 26 respectively. The preheater 23 is connected to the steam turbine intermediate-pressure cylinder 26.

[0040] Embodiment 6 of the present invention: An energy storage system with temperature zone matching series-parallel compression and turbine side high-pressure heater removal, comprising a Brayton heat pump circulation unit 1, wherein the Brayton heat pump circulation unit 1 comprises a first-stage compressor 2, a second-stage compressor 3, an air-molten salt heat exchanger group 4 and an air-air heat exchanger group 5, the air-air heat exchanger group 5 is connected to an expander 6, and the air-molten salt heat exchanger group 4 is sequentially connected to a dual-salt multi-tank heat storage unit 7, a steam Rankine cycle unit 8 and a generator 9; the air-molten salt heat exchanger group 4 is provided with at least five sets, and the air-molten salt heat exchanger group 4 comprises an air-molten salt heat exchanger A 10, an air-molten salt heat exchanger B 11, and an air-molten salt heat exchanger C 12, D air-molten salt heat exchanger 13, E air-molten salt heat exchanger 14, A air-molten salt heat exchanger 10 is sequentially connected to B air-molten salt heat exchanger 11 and is arranged between the first compressor 2 and the second compressor 3, the second compressor 3 is sequentially connected to C air-molten salt heat exchanger 12, D air-molten salt heat exchanger 13, E air-molten salt heat exchanger 14, B air-molten salt heat exchanger 11 is connected to the air-air heat exchanger group 5; the dual-salt multi-tank heat storage unit 7 includes a solar salt molten salt high-temperature heat storage tank 15, a solar salt molten salt low-temperature heat storage tank 16, a Hitec salt molten salt high-temperature heat storage tank 17, a Hitec salt molten salt medium-temperature heat storage tank 18 and a Hitec The salt molten salt low temperature heat storage tank 19, the solar salt molten salt high temperature heat storage tank 15, the solar salt molten salt low temperature heat storage tank 16, the Hitec salt molten salt high temperature heat storage tank 17, the Hitec salt molten salt medium temperature heat storage tank 18 and the Hitec salt molten salt low temperature heat storage tank 19 are all connected to the steam Rankine cycle unit 8, the C air-molten salt heat exchanger 12 is respectively connected to the solar salt molten salt high temperature heat storage tank 15, the solar salt molten salt low temperature heat storage tank 16, the D air-molten salt heat exchanger 13 is respectively connected to the Hitec salt molten salt high temperature heat storage tank 17, the Hitec salt molten salt medium temperature heat storage tank 18, the E air-molten salt heat exchanger 14 is respectively connected to the Hitec salt molten salt medium temperature heat storage tank 18, the H itec salt molten salt low-temperature heat storage tank 19; the steam Rankine cycle unit 8 includes a multi-stage steam turbine unit 20, a superheater 21, an evaporator 22, a preheater 23, and a reheater 24 connected in sequence, the superheater 21 is respectively connected to the solar salt molten salt high-temperature heat storage tank 15 and the solar salt molten salt low-temperature heat storage tank 16, the evaporator 22 is respectively connected to the Hitec salt molten salt high-temperature heat storage tank 17 and the Hitec salt molten salt medium-temperature heat storage tank 18, the preheater 23 is respectively connected to the Hitec salt molten salt medium-temperature heat storage tank 18 and the Hitec salt molten salt low-temperature heat storage tank 19, and the reheater 24 is respectively connected to the solar salt molten salt high-temperature heat storage tank 15 and the solar salt molten salt low-temperature heat storage tank 16;The multi-stage steam turbine unit 20 includes a steam turbine high-pressure cylinder 25, a steam turbine intermediate-pressure cylinder 26, and a steam turbine low-pressure cylinder 27, which are connected in sequence. The low-pressure cylinder 27 is connected to a low-pressure heater group 28. The superheater 21 is connected to the steam turbine high-pressure cylinder 25, the reheater 24 is connected to the steam turbine high-pressure cylinder 25 and the steam turbine intermediate-pressure cylinder 26, respectively, and the preheater 23 is connected to the steam turbine intermediate-pressure cylinder 26. A deaerator 29 is provided between the steam turbine intermediate-pressure cylinder 26 and the preheater 23, and the deaerator 29 is also connected to the low-pressure heater group 28.

[0041] Embodiment 7 of the present invention: An energy storage system with temperature zone matching series-parallel compression and steam turbine side high-pressure heater removal, including a Brayton heat pump circulation unit 1, the Brayton heat pump circulation unit 1 includes a first-stage compressor 2, a second-stage compressor 3, an air-molten salt heat exchanger group 4 and an air-air heat exchanger group 5, the air-air heat exchanger group 5 is connected to an expander 6, and the air-molten salt heat exchanger group 4 is sequentially connected to a dual-salt multi-tank heat storage unit 7, a steam Rankine cycle unit 8 and a generator 9; the air-molten salt heat exchanger group 4 is provided with at least five sets, and the air-molten salt heat exchanger group 4 includes an air-molten salt heat exchanger A 10, an air-molten salt heat exchanger B 11, and an air-molten salt heat exchanger C 12, D air-molten salt heat exchanger 13, E air-molten salt heat exchanger 14, A air-molten salt heat exchanger 10 is sequentially connected to B air-molten salt heat exchanger 11 and is arranged between the first compressor 2 and the second compressor 3, the second compressor 3 is sequentially connected to C air-molten salt heat exchanger 12, D air-molten salt heat exchanger 13, E air-molten salt heat exchanger 14, B air-molten salt heat exchanger 11 is connected to the air-air heat exchanger group 5; the dual-salt multi-tank heat storage unit 7 includes a solar salt molten salt high-temperature heat storage tank 15, a solar salt molten salt low-temperature heat storage tank 16, a Hitec salt molten salt high-temperature heat storage tank 17, a Hitec salt molten salt medium-temperature heat storage tank 18 and a Hitec The salt molten salt low temperature heat storage tank 19, the solar salt molten salt high temperature heat storage tank 15, the solar salt molten salt low temperature heat storage tank 16, the Hitec salt molten salt high temperature heat storage tank 17, the Hitec salt molten salt medium temperature heat storage tank 18 and the Hitec salt molten salt low temperature heat storage tank 19 are all connected to the steam Rankine cycle unit 8, the C air-molten salt heat exchanger 12 is respectively connected to the solar salt molten salt high temperature heat storage tank 15, the solar salt molten salt low temperature heat storage tank 16, the D air-molten salt heat exchanger 13 is respectively connected to the Hitec salt molten salt high temperature heat storage tank 17, the Hitec salt molten salt medium temperature heat storage tank 18, the E air-molten salt heat exchanger 14 is respectively connected to the Hitec salt molten salt medium temperature heat storage tank 18, the H itec salt molten salt low-temperature heat storage tank 19; the steam Rankine cycle unit 8 includes a multi-stage steam turbine unit 20, a superheater 21, an evaporator 22, a preheater 23, and a reheater 24 connected in sequence, the superheater 21 is respectively connected to the solar salt molten salt high-temperature heat storage tank 15 and the solar salt molten salt low-temperature heat storage tank 16, the evaporator 22 is respectively connected to the Hitec salt molten salt high-temperature heat storage tank 17 and the Hitec salt molten salt medium-temperature heat storage tank 18, the preheater 23 is respectively connected to the Hitec salt molten salt medium-temperature heat storage tank 18 and the Hitec salt molten salt low-temperature heat storage tank 19, and the reheater 24 is respectively connected to the solar salt molten salt high-temperature heat storage tank 15 and the solar salt molten salt low-temperature heat storage tank 16;The multi-stage steam turbine unit 20 includes a steam turbine high-pressure cylinder 25, a steam turbine intermediate-pressure cylinder 26, and a steam turbine low-pressure cylinder 27, which are connected in sequence. The steam turbine low-pressure cylinder 27 is connected to a low-pressure heater group 28. The superheater 21 is connected to the steam turbine high-pressure cylinder 25, the reheater 24 is connected to the steam turbine high-pressure cylinder 25 and the steam turbine intermediate-pressure cylinder 26, respectively, and the preheater 23 is connected to the steam turbine intermediate-pressure cylinder 26. A deaerator 29 is provided between the steam turbine intermediate-pressure cylinder 26 and the preheater 23. The deaerator 29 is also connected to the low-pressure heater group 28. The steam turbine low-pressure cylinder 27 is connected to a condenser 30, which is also connected to the low-pressure heater group 28.

[0042] Embodiment 8 of the present invention: An energy storage system with temperature zone matching series-parallel compression and turbine side high-pressure heater removal, comprising a Brayton heat pump circulation unit 1, wherein the Brayton heat pump circulation unit 1 comprises a primary compressor 2, a secondary compressor 3, an air-molten salt heat exchanger group 4 and an air-air heat exchanger group 5, the air-air heat exchanger group 5 is connected to an expander 6, and the air-molten salt heat exchanger group 4 is sequentially connected to a dual-salt multi-tank heat storage unit 7, a steam Rankine cycle unit 8 and a generator 9; the air-molten salt heat exchanger group 4 is provided with at least five sets, and the air-molten salt heat exchanger group 4 comprises an air-molten salt heat exchanger A 10, an air-molten salt heat exchanger B 11, and an air-molten salt heat exchanger C 12, D air-molten salt heat exchanger 13, E air-molten salt heat exchanger 14, A air-molten salt heat exchanger 10 is sequentially connected to B air-molten salt heat exchanger 11 and is arranged between the first compressor 2 and the second compressor 3, the second compressor 3 is sequentially connected to C air-molten salt heat exchanger 12, D air-molten salt heat exchanger 13, E air-molten salt heat exchanger 14, B air-molten salt heat exchanger 11 is connected to the air-air heat exchanger group 5; the dual-salt multi-tank heat storage unit 7 includes a solar salt molten salt high-temperature heat storage tank 15, a solar salt molten salt low-temperature heat storage tank 16, a Hitec salt molten salt high-temperature heat storage tank 17, a Hitec salt molten salt medium-temperature heat storage tank 18 and a Hitec The salt molten salt low temperature heat storage tank 19, the solar salt molten salt high temperature heat storage tank 15, the solar salt molten salt low temperature heat storage tank 16, the Hitec salt molten salt high temperature heat storage tank 17, the Hitec salt molten salt medium temperature heat storage tank 18 and the Hitec salt molten salt low temperature heat storage tank 19 are all connected to the steam Rankine cycle unit 8, the C air-molten salt heat exchanger 12 is respectively connected to the solar salt molten salt high temperature heat storage tank 15, the solar salt molten salt low temperature heat storage tank 16, the D air-molten salt heat exchanger 13 is respectively connected to the Hitec salt molten salt high temperature heat storage tank 17, the Hitec salt molten salt medium temperature heat storage tank 18, the E air-molten salt heat exchanger 14 is respectively connected to the Hitec salt molten salt medium temperature heat storage tank 18, the H itec salt molten salt low-temperature heat storage tank 19; the steam Rankine cycle unit 8 includes a multi-stage steam turbine unit 20, a superheater 21, an evaporator 22, a preheater 23, and a reheater 24 connected in sequence, the superheater 21 is respectively connected to the solar salt molten salt high-temperature heat storage tank 15 and the solar salt molten salt low-temperature heat storage tank 16, the evaporator 22 is respectively connected to the Hitec salt molten salt high-temperature heat storage tank 17 and the Hitec salt molten salt medium-temperature heat storage tank 18, the preheater 23 is respectively connected to the Hitec salt molten salt medium-temperature heat storage tank 18 and the Hitec salt molten salt low-temperature heat storage tank 19, and the reheater 24 is respectively connected to the solar salt molten salt high-temperature heat storage tank 15 and the solar salt molten salt low-temperature heat storage tank 16;The multi-stage steam turbine unit 20 includes a steam turbine high-pressure cylinder 25, a steam turbine intermediate-pressure cylinder 26, and a steam turbine low-pressure cylinder 27 connected in sequence. The steam turbine low-pressure cylinder 27 is connected to a low-pressure heater group 28. The superheater 21 is connected to the steam turbine high-pressure cylinder 25. The reheater 24 is respectively connected to the steam turbine high-pressure cylinder 25 and the steam turbine intermediate-pressure cylinder 26. The preheater 23 is connected to the steam turbine intermediate-pressure cylinder 26. A deaerator 29 is provided between the steam turbine intermediate-pressure cylinder 26 and the preheater 23. The deaerator 29 is also connected to the low-pressure heater group 28. The steam turbine low-pressure cylinder 27 is connected to a condenser 30. The condenser 30 is also connected to the low-pressure heater group 28. The solar salt molten salt high-temperature heat storage tank 15 contains solar salt at a temperature of 553-566°C, preferably 557°C. The solar salt molten salt low-temperature heat storage tank 16 contains solar salt at a temperature of 411-421°C, preferably 415°C. The Hitec salt molten salt high-temperature heat storage tank 17 contains Hitec salt at a temperature of 411-421°C, preferably 415°C. The Hitec salt molten salt medium-temperature heat storage tank 18 contains Hitec salt at a temperature of 357-371°C, preferably 366°C. The Hitec salt molten salt low-temperature heat storage tank 19 contains Hitec salt at a temperature of 202-213°C, preferably 208°C.

[0043] Embodiment 9 of the present invention: Control method for energy storage system with temperature zone matching series-parallel compression and turbine-side high-pressure heater removal,

[0044] When the power consumption of the power grid is low, the heat pump side passage and the heat exchange passage between the molten salt side and the heat pump side are opened at the same time, and the Brayton heat pump circulation unit 1 uses low-cost electricity to act on the first-stage compressor 2 and the second-stage compressor 3, so that the first-stage compressor 2 and the second-stage compressor 3 work to pressurize the low-temperature and low-pressure air to high-pressure and high-temperature gas. Then, the air undergoes heat exchange treatment, and the high-temperature heat is stored in the solar salt molten salt high-temperature heat storage tank 15 and the solar salt molten salt low-temperature heat storage tank 16, and the low-temperature heat is stored in the Hitec salt molten salt high-temperature heat storage tank 17, the Hitec salt molten salt medium-temperature heat storage tank 18 and the Hitec salt molten salt low-temperature heat storage tank 19. Then, after expansion and environmental heating treatment, it enters the first-stage compressor 2 and the second-stage compressor 3 for circulation. At this time, the coal-fired power generation unit stops working;

[0045] During peak power consumption in the power grid, the turbine side passage and the heat exchange passages between the molten salt side and the heat pump side are opened at the same time, heat is released through the molten salt, and steam is used to pass through the superheater 21, the reheater 24, the evaporator 22, and the preheater 23 to heat the working medium in the steam Rankine cycle unit 8, so that the turbine works to generate electricity. At this time, the Brayton heat pump circulation unit 1 stops working.

[0046] Embodiment 10 of the present invention: Control method for energy storage system with temperature zone matching series-parallel compression and turbine-side high-pressure heater removal,

[0047] When the power consumption of the power grid is low, the heat pump side passage and the heat exchange passage between the molten salt side and the heat pump side are opened at the same time, and the Brayton heat pump circulation unit 1 uses low-cost electricity to act on the first-stage compressor 2 and the second-stage compressor 3, so that the first-stage compressor 2 and the second-stage compressor 3 work to pressurize the low-temperature and low-pressure air to high-pressure and high-temperature gas. Then, the air undergoes heat exchange treatment, and the high-temperature heat is stored in the solar salt molten salt high-temperature heat storage tank 15 and the solar salt molten salt low-temperature heat storage tank 16, and the low-temperature heat is stored in the Hitec salt molten salt high-temperature heat storage tank 17, the Hitec salt molten salt medium-temperature heat storage tank 18 and the Hitec salt molten salt low-temperature heat storage tank 19. Then, after expansion and environmental heating treatment, it enters the first-stage compressor 2 and the second-stage compressor 3 for circulation. At this time, the coal-fired power generation unit stops working;

[0048] During peak power demand in the grid, the steam turbine side passage and the heat exchange passages between the molten salt side and the heat pump side are opened simultaneously, heat is released through the molten salt, and steam is used to pass through the superheater 21, the reheater 24, the evaporator 22, and the preheater 23, so that the working medium in the steam Rankine cycle unit 8 is heated, causing the steam turbine to operate and generate electricity. At this time, the Brayton heat pump cycle unit 1 stops working;

[0049] When the Brayton heat pump circulation unit 1 is working, the air is split after passing through the first-stage compressor 2, and part of the air passes through the hot side of the A air-molten salt heat exchanger 10 and the Hitec salt molten salt high-temperature heat storage tank 17 and the B air-molten salt heat exchanger 11 and the Hitec salt molten salt medium-temperature heat storage tank 18 in sequence, and part of the air enters the secondary compressor 3, and then the air passes through the C air-molten salt heat exchanger 12 and the solar salt molten salt high-temperature heat storage tank 15, the solar salt molten salt low-temperature heat storage tank 16 in sequence. The hot side of the heat exchange, the D air-molten salt heat exchanger 13 and the Hitec salt molten salt high-temperature heat storage tank 17 and the E air-molten salt heat exchanger 14 and the Hitec salt molten salt medium-temperature heat storage tank 18, the Hitec salt molten salt low-temperature heat storage tank 19 are exchanged, and then enter the hot side of the air-air heat exchanger group 5 respectively, and are connected to the inlet of the expander 6, and are expanded into the turbine respectively;

[0050] When the steam Rankine cycle unit 8 is working, the steam comes out of the superheater 21 and passes through the turbine high-pressure cylinder 25, the turbine intermediate-pressure cylinder 26, and the turbine low-pressure cylinder 27 in sequence to generate electricity. The steam coming out of the turbine high-pressure cylinder 25 passes through the reheater 24, and a portion is transported to the turbine intermediate-pressure cylinder 26, and the other portion enters the turbine low-pressure cylinder 27. After performing work, it passes through the condenser 30 and the low-pressure heater group 28 and enters the deaerator 29. After passing through the deaerator 29, it enters the preheater 23, the evaporator 22, and the superheater 21 in sequence to exchange heat with the dual-salt multi-tank heat storage unit 7;

[0051] When the dual-salt multi-tank heat storage unit 7 is working, the steam comes out from the cold side of the heat exchange between the A air-molten salt heat exchanger 10 and the solar salt molten salt high-temperature heat storage tank 15 and stores the heat in the solar salt molten salt high-temperature heat storage tank 15. At the peak, the steam passes through the superheater 21 and the reheater 24, releases the stored heat into the steam Rankine cycle unit 8, and then enters the solar salt molten salt low-temperature heat storage tank 16; the steam comes out from the cold side of the heat exchange between the D air-molten salt heat exchanger 13 and the Hitec salt molten salt high-temperature heat storage tank 17 and stores the heat in the Hitec salt molten salt. In the high-temperature heat storage tank 17, at peak times, the stored heat is released into the steam Rankine cycle unit 8 through the evaporator 22, and then enters the Hitec salt molten salt medium-temperature heat storage tank 18; the steam comes out from the cold side of the E air-molten salt heat exchanger 14 and the Hitec salt molten salt medium-temperature heat storage tank 18 after heat exchange, and stores the heat in the Hitec salt molten salt medium-temperature heat storage tank 18. At peak times, the steam passes through the evaporator 22, releases the stored heat into the steam Rankine cycle unit 8, and then enters the Hitec salt molten salt low-temperature heat storage tank 19.

[0052] The working principle of an embodiment of the present invention is as follows:

[0053] When the present invention works:

[0054] When the power consumption of the power grid is low, the heat pump side passage and the heat exchange passage between the molten salt side and the heat pump side are opened at the same time, and the Brayton heat pump circulation unit 1 uses low-cost electricity to act on the first-stage compressor 2 and the second-stage compressor 3, so that the first-stage compressor 2 and the second-stage compressor 3 work to pressurize the low-temperature and low-pressure air to high-pressure and high-temperature gas. Then, the air undergoes heat exchange treatment, and the high-temperature heat is stored in the solar salt molten salt high-temperature heat storage tank 15 and the solar salt molten salt low-temperature heat storage tank 16, and the low-temperature heat is stored in the Hitec salt molten salt high-temperature heat storage tank 17, the Hitec salt molten salt medium-temperature heat storage tank 18 and the Hitec salt molten salt low-temperature heat storage tank 19. Then, after expansion and environmental heating treatment, it enters the first-stage compressor 2 and the second-stage compressor 3 for circulation. At this time, the coal-fired power generation unit stops working;

[0055] During peak power consumption in the power grid, the turbine side passage and the heat exchange passages between the molten salt side and the heat pump side are opened at the same time, heat is released through the molten salt, and steam is used to pass through the superheater 21, the reheater 24, the evaporator 22, and the preheater 23 to heat the working medium in the steam Rankine cycle unit 8, so that the turbine works to generate electricity. At this time, the Brayton heat pump circulation unit 1 stops working.

Claims

1. A temperature zone matching series-parallel compression and turbine side high pressure heater removal energy storage system, comprising a Brayton heat pump circulation unit (1), characterized in that: The Brayton heat pump circulation unit (1) comprises a primary compressor (2), a secondary compressor (3), an air-molten salt heat exchanger group (4) and an air-air heat exchanger group (5); the air-air heat exchanger group (5) is connected to an expander (6); the air-molten salt heat exchanger group (4) is sequentially connected to a dual-salt multi-tank heat storage unit (7), a steam Rankine cycle unit (8) and a generator (9).

2. The energy storage system with temperature zone matching series-parallel compression and turbine side high pressure heater removal according to claim 1 is characterized in that: The air-molten salt heat exchanger group (4) is provided with at least five sets, and the air-molten salt heat exchanger group (4) includes an air-molten salt heat exchanger A (10), an air-molten salt heat exchanger B (11), an air-molten salt heat exchanger C (12), an air-molten salt heat exchanger D (13), and an air-molten salt heat exchanger E (14). The air-molten salt heat exchanger A (10) is sequentially connected to the air-molten salt heat exchanger B (11) and is arranged between the first-stage compressor (2) and the second-stage compressor (3). The second-stage compressor (3) is sequentially connected to the air-molten salt heat exchanger C (12), the air-molten salt heat exchanger D (13), and the air-molten salt heat exchanger E (14). The air-molten salt heat exchanger B (11) is connected to the air-air heat exchanger group (5).

3. The energy storage system with temperature zone matching series-parallel compression and turbine side high pressure heater removal according to claim 2 is characterized in that: The dual-salt multi-tank heat storage unit (7) comprises a solar salt molten salt high-temperature heat storage tank (15), a solar salt molten salt low-temperature heat storage tank (16), a HitecHitec salt molten salt high-temperature heat storage tank (17), a HitecHitec salt molten salt medium-temperature heat storage tank (18) and a HitecHitec salt molten salt low-temperature heat storage tank (19), a solar salt molten salt high-temperature heat storage tank (15), a solar salt molten salt low-temperature heat storage tank (16), a HitecHitec salt molten salt high-temperature heat storage tank (17), a Hitec salt molten salt medium-temperature heat storage tank (18) and a HitecHitec salt molten salt low-temperature heat storage tank (19). Itec salt molten salt low-temperature heat storage tanks (19) are all connected to the steam Rankine cycle unit (8), C air-molten salt heat exchangers (12) are respectively connected to the solar salt molten salt high-temperature heat storage tank (15) and the solar salt molten salt low-temperature heat storage tank (16), D air-molten salt heat exchangers (13) are respectively connected to the Hitec salt molten salt high-temperature heat storage tank (17) and the Hitec salt molten salt medium-temperature heat storage tank (18), and E air-molten salt heat exchangers (14) are respectively connected to the Hitec salt molten salt medium-temperature heat storage tank (18) and the Hitec salt molten salt low-temperature heat storage tank (19).

4. The energy storage system with temperature zone matching series-parallel compression and turbine side high pressure heater removal according to claim 3 is characterized in that: The steam Rankine cycle unit (8) comprises a multi-stage steam turbine unit (20), a superheater (21), an evaporator (22), a preheater (23), and a reheater (24) connected in sequence, wherein the superheater (21) is respectively connected to a solar salt molten salt high-temperature heat storage tank (15) and a solar salt molten salt low-temperature heat storage tank (16), the evaporator (22) is respectively connected to a Hitec salt molten salt high-temperature heat storage tank (17) and a Hitec salt molten salt medium-temperature heat storage tank (18), the preheater (23) is respectively connected to a Hitec salt molten salt medium-temperature heat storage tank (18) and a Hitec salt molten salt low-temperature heat storage tank (19), and the reheater (24) is respectively connected to a solar salt molten salt high-temperature heat storage tank (15) and a solar salt molten salt low-temperature heat storage tank (16).

5. The energy storage system with temperature zone matching series-parallel compression and turbine side high pressure heater removal according to claim 4 is characterized in that: The multi-stage steam turbine unit (20) comprises a steam turbine high-pressure cylinder (25), a steam turbine intermediate-pressure cylinder (26), and a steam turbine low-pressure cylinder (27) connected in sequence, a low-pressure heater unit (28) being connected to the steam turbine low-pressure cylinder (27), a superheater (21) being connected to the steam turbine high-pressure cylinder (25), a reheater (24) being respectively connected to the steam turbine high-pressure cylinder (25) and the steam turbine intermediate-pressure cylinder (26), and a preheater (23) being connected to the steam turbine intermediate-pressure cylinder (26).

6. The energy storage system with temperature zone matching series-parallel compression and turbine side high pressure heater removal according to claim 5 is characterized in that: A deaerator (29) is provided between the steam turbine intermediate pressure cylinder (26) and the preheater (23), and the deaerator (29) is also connected to the low-pressure heater group (28).

7. The energy storage system with temperature zone matching series-parallel compression and turbine side high pressure heater removal according to claim 6 is characterized in that: The low-pressure cylinder (27) of the steam turbine is connected to a condenser (30), and the condenser (30) is also connected to a low-pressure heater group (28).

8. A control method for the system according to claims 1-7, characterized in that: When the power consumption of the power grid is low, the heat pump side passage and the heat exchange passage between the molten salt side and the heat pump side are opened at the same time, and the Brayton heat pump circulation unit (1) uses low-cost electricity to act on the first-stage compressor (2) and the second-stage compressor (3), so that the first-stage compressor (2) and the second-stage compressor (3) work to pressurize the low-temperature and low-pressure air into high-pressure and high-temperature gas. Then, the air is subjected to heat exchange treatment, and the high-temperature heat is stored in the solar salt molten salt high-temperature heat storage tank (15) and the solar salt molten salt low-temperature heat storage tank (16), and the low-temperature heat is stored in the Hitec salt molten salt high-temperature heat storage tank (17), the Hitec salt molten salt medium-temperature heat storage tank (18) and the Hitec salt molten salt low-temperature heat storage tank (19). Then, after expansion and environmental heating treatment, the air enters the first-stage compressor (2) and the second-stage compressor (3) for circulation. At this time, the coal-fired power generation unit stops working; During peak power consumption in the power grid, the steam turbine side passage and the heat exchange passages on the molten salt side and the heat pump side are opened simultaneously, heat is released through the molten salt, and steam is used to pass through the superheater (21), the reheater (24), the evaporator (22), and the preheater (23), so that the working medium in the steam Rankine cycle unit (8) is heated, and the steam turbine is operated to generate electricity. At this time, the Brayton heat pump cycle unit (1) stops working.

9. The control method of the system according to claim 8, characterized in that: When the Brayton heat pump circulation unit (1) is working, the air is divided after passing through the first-stage compressor (2), a part of which is sequentially passed through the hot side of the A air-molten salt heat exchanger (10) and the Hitec salt molten salt high-temperature heat storage tank (17) for heat exchange and the hot side of the B air-molten salt heat exchanger (11) and the Hitec salt molten salt medium-temperature heat storage tank (18) for heat exchange, and a part of which enters the second-stage compressor (3), and then the air is sequentially passed through the C air-molten salt heat exchanger (12) and the solar salt molten salt high-temperature heat storage tank (18) for heat exchange. The hot side of the heat exchanger (15) and the solar salt molten salt low-temperature heat storage tank (16), the hot side of the heat exchanger (13) and the Hitec salt molten salt high-temperature heat storage tank (17), and the hot side of the heat exchanger (14) and the Hitec salt molten salt medium-temperature heat storage tank (18) and the Hitec salt molten salt low-temperature heat storage tank (19), then enter the hot side of the air-air heat exchanger group (5) respectively and are connected to the inlet of the expander (6) to perform expansion turbine respectively; When the steam Rankine cycle unit (8) is working, the steam comes out of the superheater (21) and passes through the turbine high-pressure cylinder (25), the turbine intermediate-pressure cylinder (26), and the turbine low-pressure cylinder (27) in sequence to generate electricity. A portion of the steam coming out of the turbine high-pressure cylinder (25) is transported to the turbine intermediate-pressure cylinder (26) through the reheater (24), and the other portion enters the turbine low-pressure cylinder (27). After doing work, the steam passes through the condenser (30) and the low-pressure heater group (28) and then enters the deaerator (29). After passing through the deaerator (29), the steam enters the preheater (23), the evaporator (22), and the superheater (21) in sequence to exchange heat with the double-salt multi-tank heat storage unit (7); When the dual-salt multi-tank heat storage unit (7) is in operation, the air comes out from the cold side of the heat exchange between the A air-molten salt heat exchanger (10) and the solar salt molten salt high-temperature heat storage tank (15) and stores heat in the solar salt molten salt high-temperature heat storage tank (15). At peak times, the air passes through the superheater (21) and the reheater (24), releases the stored heat into the steam Rankine cycle unit (8), and then enters the solar salt molten salt low-temperature heat storage tank (16); the air comes out from the cold side of the heat exchange between the D air-molten salt heat exchanger (13) and the Hitec salt molten salt high-temperature heat storage tank (17) and stores heat in the Hitec salt molten salt. In the high-temperature heat storage tank (17), at peak times, the stored heat is released into the steam Rankine cycle unit (8) through the evaporator (22), and then enters the Hitec salt molten salt medium-temperature heat storage tank (18); the air comes out from the cold side of the heat exchange between the E air-molten salt heat exchanger (14) and the Hitec salt molten salt medium-temperature heat storage tank (18) and stores the heat in the Hitec salt molten salt medium-temperature heat storage tank (18). At peak times, the air passes through the evaporator (22), releases the stored heat into the steam Rankine cycle unit (8), and then enters the Hitec salt molten salt low-temperature heat storage tank (19).

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