Compressed air energy storage power station molten salt heat storage and exchange system and operation method

Abstract

This invention discloses a molten salt heat exchange system and its operation method for a compressed air energy storage power station, belonging to the technical field of compressed air energy storage systems. The heat exchange system includes a compressor. The high-pressure gas outlet of the compressor is connected to the high-pressure gas inlet of the gas storage tank after passing through a compression-side heat transfer oil-air heat exchanger, a compression-side medium-low temperature heat exchanger, and a compression-side isolation valve. The high-pressure gas outlet of the gas storage tank is connected to a turbine after passing through an expansion-side isolation valve, an expansion-side low-temperature heat exchanger, and an expansion-side heat transfer oil-air heat exchanger. The compression-side and expansion-side heat transfer oil-air heat exchangers exchange heat with the low-temperature salt tank and the high-temperature salt tank through the compression-side and expansion-side molten salt-heat transfer oil heat exchangers, respectively. This invention can effectively isolate the high-pressure gas-side medium from the molten salt circulation loop, effectively avoiding the risk of rupture of the heat exchange tubes inside the molten salt-air heat exchanger.

Description

Technical Field

[0001] This invention relates to a molten salt heat exchange system and its operation method for a compressed air energy storage power station, belonging to the technical field of compressed air energy storage systems. Background Technology

[0002] Compressed air energy storage technology, as one of the core technologies for large-scale, long-term energy storage, has broad application prospects in areas such as peak shaving in new power systems and renewable energy consumption due to its advantages of large storage capacity, long operating life, safety, and environmental friendliness. Molten salt thermal energy storage technology, with its high thermal density and excellent heat transfer performance, has gradually become the mainstream thermal energy storage solution for compressed air energy storage power plants. The coupled application of these two technologies can effectively improve the efficiency of power plant systems and address the pain points of heat waste and high carbon emissions associated with traditional compressed air energy storage. Currently, in the molten salt-air heat exchange system on the expansion side of compressed air energy storage power plants, heat transfer is generally achieved through direct heat exchange between molten salt and high-pressure air. However, this heat exchange method has significant safety hazards and technical defects. Because the pressure on the high-pressure gas side is much higher than that on the molten salt side, and heat exchanger tube bundle damage is a common operational failure, if the heat exchange tubes inside the molten salt-air heat exchanger rupture, high-pressure air will directly invade the molten salt circulation system. Molten salt tanks are mostly atmospheric or low-pressure vessels and cannot withstand the pressure surge from the influx of high-pressure air, easily causing overpressure in the molten salt thermal storage system. This can lead to safety accidents such as molten salt tank leaks and salt spraying, and may also exacerbate molten salt degradation and pipe blockage, affecting system stability and equipment lifespan. Current technologies lack reliable solutions to effectively isolate the high-pressure gas side from the molten salt circulation loop, making it difficult to meet the long-term, high-safety, and high-reliability operation requirements of large-scale compressed air energy storage power plants. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a molten salt heat exchange system and operation method for a compressed air energy storage power station, which can effectively isolate the high-pressure gas-side medium from the molten salt circulation loop and effectively avoid the risk of rupture of the heat exchange tube inside the molten salt-air heat exchanger.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0005] In a first aspect, the present invention discloses a molten salt heat exchange system for a compressed air energy storage power station, comprising a compressor, wherein the high-pressure gas outlet of the compressor is connected to the high-pressure gas inlet of the gas storage tank via a compression-side heat transfer oil-air heat exchanger, a compression-side medium-low temperature heat exchanger and a compression-side isolation valve in sequence, and the high-pressure gas outlet of the gas storage tank is connected to the turbine via an expansion-side isolation valve, an expansion-side low-temperature heat exchanger and an expansion-side heat transfer oil-air heat exchanger in sequence.

[0006] The shell-side outlet of the compression-side heat transfer oil-air heat exchanger is connected to the tube-side inlet of the compression-side molten salt-heat transfer oil heat exchanger after passing through a compression-side heat transfer oil isolation valve and a compression-side heat transfer oil regulating valve in sequence. The tube-side outlet of the compression-side molten salt-heat transfer oil heat exchanger is connected to the inlet of the compression-side heat transfer oil circulation pump, and the outlet of the compression-side heat transfer oil circulation pump is connected to the shell-side inlet of the compression-side heat transfer oil-air heat exchanger. The shell-side outlet of the expansion-side heat transfer oil-air heat exchanger is connected to the inlet of the expansion-side heat transfer oil circulation pump in sequence. The outlet of the expansion-side heat transfer oil circulation pump is connected to the shell-side inlet of the expansion-side heat transfer oil-air heat exchanger after passing through the expansion-side molten salt-heat transfer oil heat exchanger, the expansion-side heat transfer oil isolation valve, and the expansion-side heat transfer oil regulating valve in sequence. The tube-side outlet of the expansion-side molten salt-heat transfer oil heat exchanger is connected to the inlet of the cryogenic salt pump after passing through a cryogenic salt tank. The outlet of the cryogenic salt pump is connected to the shell-side inlet of the compression-side molten salt-heat transfer oil heat exchanger. The shell-side outlet of the compression-side molten salt-heat transfer oil heat exchanger passes through a compression-side molten salt isolation valve, a compression-side molten salt regulating valve, and a high-temperature salt tank in sequence before being connected to the inlet of the high-temperature salt pump. The outlet of the high-temperature salt pump passes through an expansion-side heat transfer oil isolation valve and an expansion-side heat transfer oil regulating valve in sequence before being connected to the tube-side inlet of the expansion-side molten salt-heat transfer oil heat exchanger.

[0007] The head of the compression-side heat transfer oil circulation pump and the expansion-side heat transfer oil circulation pump is 48~52m.

[0008] The tube-side outlet of the compression-side molten salt-heat transfer oil heat exchanger and the inlet of the compression-side heat transfer oil circulation pump are connected to the compression-side closed expansion heat transfer oil tank; the shell-side outlet of the expansion-side heat transfer oil-air heat exchanger and the inlet of the expansion-side heat transfer oil circulation pump are connected to the expansion-side closed expansion heat transfer oil tank.

[0009] The volume of the compression-side closed expansion heat transfer oil tank and the expansion-side closed expansion heat transfer oil tank is 8~12m³. 3 .

[0010] The compression-side closed expansion heat transfer oil tank and the expansion-side closed expansion heat transfer oil tank are arranged at a high position. The height difference between the closed expansion heat transfer oil tank and the inlet of the compression-side heat transfer oil circulation pump should be no less than 20m, and the height difference between the expansion-side closed expansion heat transfer oil tank and the inlet of the expansion-side heat transfer oil circulation pump should be no less than 20m.

[0011] The cryogenic salt tank is designed with a pressure of 1.9~2.1MPa and a temperature of 290~310℃.

[0012] The high-temperature salt tank is designed with a pressure of 1.9~2.1MPa and a temperature of 390~410℃.

[0013] The expansion-side isolation valve includes a first isolation valve on the compression side of the gas storage tank and a second isolation valve on the compression side of the gas storage tank, which are connected in series. The expansion-side isolation valve includes a first isolation valve on the expansion side of the gas storage tank and a second isolation valve on the expansion side of the gas storage tank, which are connected in series.

[0014] The tube-side outlet of the expansion-side heat transfer oil-air heat exchanger and the tube-side outlet of the compression-side molten salt-heat transfer oil heat exchanger are connected sequentially through a first isolation valve and a second isolation valve of the heat transfer oil interconnection pipeline.

[0015] Secondly, this invention discloses an operation method for a molten salt heat exchange system in a compressed air energy storage power station.

[0016] When applied to energy storage applications, the following steps are included:

[0017] Start the compression-side heat transfer oil pump and the compression-side heat transfer oil isolation valve, and gradually open the compression-side heat transfer oil regulating valve to establish a stable heat transfer oil circulation loop.

[0018] Open the compression side molten salt isolation valve on the outlet side of the cryogenic molten salt tank, start the cryogenic molten salt pump, and gradually open the compression side molten salt regulating valve on the outlet side of the cryogenic molten salt tank to establish a stable molten salt circulation loop.

[0019] Start the compressor and adjust the opening of the compressor-side heat transfer oil regulating valve to ensure that the outlet temperature of the heat transfer oil on the shell side of the compressor-side heat transfer oil-air heat exchanger is maintained at 350℃. Adjust the opening of the compressor-side molten salt regulating valve on the outlet side of the low-temperature molten salt tank to ensure that the outlet temperature of the molten salt on the shell side of the compressor-side molten salt-heat transfer oil heat exchanger is maintained at 345℃.

[0020] When applied to energy release conditions, the following steps are included:

[0021] Start the expansion-side heat transfer oil pump and the expansion-side heat transfer oil isolation valve, and gradually open the expansion-side heat transfer oil regulating valve to establish a stable heat transfer oil circulation loop.

[0022] Open the expansion side molten salt isolation valve on the outlet side of the high-temperature molten salt tank, start the high-temperature molten salt pump, and gradually open the expansion side molten salt regulating valve on the outlet side of the high-temperature molten salt tank to establish a stable molten salt circulation loop.

[0023] Open the expansion side isolation valve on the gas outlet side of the gas storage tank, start the air turbine, and ensure that the air temperature at the tube outlet of the expansion side heat transfer oil-air heat exchanger is maintained at 330℃ by adjusting the opening of the expansion side heat transfer oil regulating valve. Ensure that the heat transfer oil temperature at the tube outlet of the expansion side molten salt-heat transfer oil heat exchanger is maintained at 340℃ by adjusting the opening of the expansion side molten salt regulating valve on the outlet side of the high temperature molten salt tank.

[0024] The beneficial effects of this invention are:

[0025] 1. Enhance system operational safety and mitigate safety risks at the source: The addition of an intermediate heat exchange loop for heat transfer oil achieves complete physical isolation between the high-pressure gas-side medium and the molten salt circulation loop. Even if the heat exchange tube inside the heat transfer oil-high-pressure air heat exchanger ruptures, the high-pressure air will only intrude into the heat transfer oil system and cannot directly enter the molten salt circulation loop and molten salt tank. Effective isolation enables zoned control of fault risks. Even if a leak occurs on the high-pressure gas side, it will not affect the normal operation of the molten salt system. This completely solves the safety hazards of overpressure in the molten salt system, leakage in the molten salt tank, and salt spraying caused by heat exchange tube rupture in the existing direct heat exchange method. It provides reliable active protection for the molten salt thermal energy storage system, ensuring the safety of personnel and equipment in the energy storage power station, significantly improving the operational stability, controllability, and fault resistance of the entire compressed air energy storage power station, and meeting the long-term, high-reliability operation requirements of large-scale energy storage power stations.

[0026] 2. Protect the molten salt system and extend equipment service life: Since high-pressure air and impurities in the pipeline will not come into direct contact with the molten salt, the risk of oxidation, deterioration, crystallization and pipeline blockage of the molten salt is effectively reduced, the heat transfer and storage performance of the molten salt is maintained stably, the cost of molten salt replacement and pipeline maintenance is reduced, and the service life of core equipment such as molten salt circulation pumps and heat exchangers is extended, thereby improving the economic efficiency of system operation and maintenance.

[0027] 3. Improve system stability and reliability: The improved solution of this invention does not affect the heat exchange efficiency between molten salt and high-pressure air, and is adaptable to compressed air expansion conditions of different pressure levels and temperature ranges, which can flexibly meet the needs of different operating loads of power plants.

[0028] 4. Simple structure, strong adaptability, and easy to promote and apply: This invention only adds a heat transfer oil intermediate heat exchange loop to the existing molten salt-air heat exchange system, without the need for large-scale modification of the original system. The structural design is simple, the modification difficulty is low, and the cost is controllable. It can be widely adapted to various types of supplementary combustion and non-supplementary combustion compressed air energy storage power stations, and has strong practicality and promotion value. It can promote the coupled application of compressed air energy storage technology and molten salt thermal energy storage technology towards a safer and more reliable direction. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of a molten salt heat exchange system for a compressed air energy storage power station according to the present invention;

[0030] The diagram is labeled as follows: 100 - Compressor; 200 - Air turbine; 310 - High-temperature salt tank; 320 - Low-temperature salt tank; 400 - Gas storage tank; 510 - Compressor-side heat transfer oil-air heat exchanger; 511 - Compressor-side medium-low temperature heat exchanger; 520 - Expansion-side heat transfer oil-air heat exchanger; 521 - Expansion-side medium-low temperature heat exchanger; 530 - Compressor-side molten salt-heat transfer oil heat exchanger; 540 - Expansion-side molten salt-heat transfer oil heat exchanger; 230 - Expansion-side heater; 610 - Compressor-side heat transfer oil circulation pump; 620 - Expansion-side heater; 230 - Expansion-side heater; 610 - Compressor-side heat transfer oil circulation pump; 620 - Expansion-side heater; 230 - Expansion-side heater; 610 - Compressor-side heat transfer oil circulation pump; 620 - Expansion-side heater; 630 - Compressor-side heat transfer oil circulation pump; 640 - Expansion-side heater; 650 - Expansion-side heater; 620 - Expansion-side heater; 630 - Expansion-side heater ... Hot oil circulating pump; 630-Cryogenic salt pump; 640-High temperature salt pump; 701-First isolation valve on the compression side of the gas storage tank; 702-Second isolation valve on the compression side of the gas storage tank; 703-First isolation valve on the expansion side of the gas storage tank; 704-Second isolation valve on the expansion side of the gas storage tank; 705-Molten salt isolation valve on the compression side; 706-Molten salt isolation valve on the expansion side; 707-Heat transfer oil isolation valve on the compression side; 708-Heat transfer oil isolation valve on the expansion side; 709-First isolation valve on the heat transfer oil interconnection pipeline; 710-Second isolation valve on the heat transfer oil interconnection pipeline; 711-Molten salt regulating valve on the compression side; 712-Molten salt regulating valve on the expansion side; 713-Heat transfer oil regulating valve on the compression side; 714-Heat transfer oil regulating valve on the expansion side; 810-Closed expansion heat transfer oil tank on the compression side; 820-Closed expansion heat transfer oil tank on the expansion side. Detailed Implementation

[0031] The present invention will be further described below. The following embodiments are only used to illustrate the technical solution of the present invention more clearly, and should not be used to limit the scope of protection of the present invention.

[0032] Example 1

[0033] like Figure 1 As shown, this invention discloses a molten salt heat exchange system for a compressed air energy storage power station, comprising a gas storage subsystem, a compression-side subsystem, an expansion-side subsystem, a molten salt heat storage subsystem, a molten salt heat exchange subsystem, and a heat transfer oil subsystem. The gas storage subsystem is connected to both the compression-side and expansion-side subsystems. During energy storage operation, gas is injected into the gas storage subsystem from the compression-side subsystem, and during energy release operation, gas is released from the gas storage subsystem to the expansion-side subsystem.

[0034] The compression subsystem includes a compressor 100, piping, and valves, while the gas storage subsystem includes a gas storage tank 400. The compressor 100 draws in air from the atmospheric environment and compresses it to obtain high-pressure gas. This high-pressure gas is then fed into the compression-side heat transfer oil-air heat exchanger 510 in the heat transfer oil heat exchange subsystem for heat exchange, and further cooled by the compression-side low-temperature heat exchanger 511 before being fed into the gas storage tank 400. The expansion subsystem includes a turbine 200, piping, and valves. The high-pressure gas stored in the gas storage tank 400 is sequentially fed into the expansion-side low-temperature heat exchanger 521 and the expansion-side heat transfer oil-air heat exchanger 520 in the heat transfer oil heat exchange subsystem for heating before being fed into the turbine 200. The high-temperature, high-pressure gas expands and performs work in the turbine 200, and the cooled air after work is discharged into the atmosphere.

[0035] The molten salt thermal storage subsystem includes a low-temperature salt tank 320 and a high-temperature salt tank 310. The molten salt heat exchange subsystem includes a compression-side molten salt-heat transfer oil heat exchanger 530 and an expansion-side molten salt-heat transfer oil heat exchanger 540, a low-temperature salt pump 630 and a high-temperature salt pump 640, a compression-side molten salt isolation valve 705 and an expansion-side molten salt isolation valve 706, and a compression-side molten salt regulating valve 711 and an expansion-side molten salt regulating valve 712. The outlet of the low-temperature salt tank 320 is connected in sequence to the low-temperature salt pump 630 and the shell-side inlet of the compression-side molten salt-heat transfer oil heat exchanger 530. The inlet of the low-temperature salt tank 320 is connected to the shell-side outlet of the expansion-side molten salt-heat transfer oil heat exchanger 540. The outlet of the high-temperature salt tank 310 is connected in sequence to the high-temperature salt pump 640, the isolation valve 706, the regulating valve 712, and the shell-side inlet of the expansion-side molten salt-heat transfer oil heat exchanger 540. The inlet of the high-temperature salt tank 310 is connected in sequence to the regulating valve 711, the isolation valve 705, and the shell-side outlet of the compression-side molten salt-heat transfer oil heat exchanger 530, forming a complete molten salt-heat transfer oil heat exchange loop.

[0036] The heat transfer oil heat exchange subsystem includes a compression-side heat transfer oil circulation pump 610 and an expansion-side heat transfer oil circulation pump 620, a compression-side medium-low temperature heat exchanger 510, an expansion-side heat transfer oil-air heat exchanger 520, a compression-side closed expansion heat transfer oil tank 810, an expansion-side closed expansion heat transfer oil tank 820, a compression-side heat transfer oil isolation valve 707, an expansion-side heat transfer oil isolation valve 708, a compression-side heat transfer oil regulating valve 713, and an expansion-side heat transfer oil regulating valve 714. The shell-side inlet of the compression-side heat transfer oil-air heat exchanger 510 is sequentially connected to the compression-side heat transfer oil circulation pump 610 and the tube-side outlet of the compression-side molten salt-heat transfer oil heat exchanger 530. The shell-side outlet of the compression-side heat transfer oil-air heat exchanger 510 is sequentially connected to the compression-side isolation valve 707, the compression-side regulating valve 713 and the tube-side inlet of the compression-side molten salt-heat transfer oil heat exchanger 530. The tube-side outlet of the compression-side molten salt-heat transfer oil heat exchanger 530 is connected to the inlet of the compression-side heat transfer oil circulation pump 610, and the outlet of the compression-side heat transfer oil circulation pump 610 is connected to the shell-side inlet of the compression-side heat transfer oil-air heat exchanger 510.

[0037] The shell-side outlet of the expansion-side heat transfer oil-air heat exchanger 520 is sequentially connected to the expansion-side heat transfer oil circulation pump 620 and the tube-side inlet of the expansion-side molten salt-heat transfer oil heat exchanger 540. The shell-side inlet of the expansion-side heat transfer oil-air heat exchanger 520 is sequentially connected to the expansion-side regulating valve 714, the expansion-side heat transfer oil isolation valve 708, and the tube-side outlet of the expansion-side molten salt-heat transfer oil heat exchanger 540.

[0038] The tube-side outlet of the expansion-side molten salt-heat transfer oil heat exchanger 540 is connected to the inlet of the cryogenic salt pump 630 after passing through the cryogenic salt tank 320. The outlet of the cryogenic salt pump 630 is connected to the shell-side inlet of the compression-side molten salt-heat transfer oil heat exchanger 530. The shell-side outlet of the compression-side molten salt-heat transfer oil heat exchanger 530 passes sequentially through the compression-side molten salt isolation valve 705, the compression-side molten salt regulating valve 711, and the high-temperature salt tank 310 before being connected to the inlet of the high-temperature salt pump 640. The outlet of the high-temperature salt pump 640 passes sequentially through the expansion-side heat transfer oil isolation valve 708 and the expansion-side heat transfer oil regulating valve 714 before being connected to the tube-side inlet of the expansion-side molten salt-heat transfer oil heat exchanger 540.

[0039] This invention adds an intermediate heat exchange loop of heat transfer oil to the molten salt-air heat exchange system on the expansion side of the compressed air energy storage unit to effectively isolate the high-pressure gas-side medium from the molten salt circulation loop. This improvement can effectively avoid the technical risk of high-pressure air intruding into the molten salt circulation system due to the rupture of the heat exchange tube inside the molten salt-air heat exchanger, causing overpressure in the molten salt heat storage system and thus inducing a safety accident in the molten salt tank. It can provide reliable protection for the molten salt system and ensure the safety and stability of the entire energy storage power station operation.

[0040] Example 2

[0041] This embodiment is a further improvement upon Embodiment 1. Specifically, the head of the hot oil circulation pump 610 and the expansion-side heat transfer oil circulation pump 620 is 48-52m, preferably 50m. The tube-side outlet of the compression-side molten salt-heat transfer oil heat exchanger 530 and the inlet of the compression-side heat transfer oil circulation pump 610 are connected to the compression-side closed-loop expansion heat transfer oil tank 810 to stabilize the pressure of the compression-side closed-loop heat transfer oil circulation system and ensure stable system operation. The shell-side outlet of the expansion-side heat transfer oil-air heat exchanger 520 and the inlet of the expansion-side heat transfer oil circulation pump 620 are connected to the expansion-side closed-loop expansion heat transfer oil tank 820 to stabilize the pressure of the expansion-side closed-loop heat transfer oil circulation system and ensure stable system operation.

[0042] The volume of the compression-side closed expansion heat transfer oil tank 810 and the expansion-side closed expansion heat transfer oil tank 820 is 8~12m³. 3 Preferably 10 m 3 .

[0043] The compression-side closed expansion heat transfer oil tank 810 and the expansion-side closed expansion heat transfer oil tank 820 are arranged at a high position. The height difference between the closed expansion heat transfer oil tank 810 and the inlet of the compression-side heat transfer oil circulation pump 610 should not be less than 20m, and the height difference between the expansion-side closed expansion heat transfer oil tank 820 and the inlet of the expansion-side heat transfer oil circulation pump 620 should not be less than 20m.

[0044] The low-temperature salt tank 320 has a design pressure of 1.9~2.1 MPa, preferably 2.0 MPa, and a design temperature of 290~310℃, preferably 300℃. The high-temperature salt tank 310 has a design pressure of 1.9~2.1 MPa, preferably 2.0 MPa, and a design temperature of 390~410℃, preferably 400℃.

[0045] The expansion-side isolation valve includes a first isolation valve 701 and a second isolation valve 702 on the compression side of the gas storage tank, which are connected in series. The expansion-side isolation valve includes a first isolation valve 703 and a second isolation valve 704 on the expansion side of the gas storage tank, which are connected in series.

[0046] The tube-side outlet of the expansion-side heat transfer oil-air heat exchanger 520 and the tube-side outlet of the compression-side molten salt-heat transfer oil heat exchanger 530 are connected sequentially through the first isolation valve 709 and the second isolation valve 710 of the heat transfer oil interconnection pipeline.

[0047] Example 3

[0048] This embodiment discloses an operation method for the molten salt heat exchange system of a compressed air energy storage power station as described in Embodiment 1 or Embodiment 2, applicable to energy storage conditions, including the following steps:

[0049] Step 1: Turn on the compression-side heat transfer oil pump 610 and the compression-side heat transfer oil isolation valve 707, and gradually open the compression-side heat transfer oil regulating valve 713 to establish a stable heat transfer oil circulation loop.

[0050] Step 2: Open the compression side molten salt isolation valve 705 on the outlet side of the cryogenic molten salt tank 320, start the cryogenic molten salt pump 630, and gradually open the compression side molten salt regulating valve 711 on the outlet side of the cryogenic molten salt tank 320 to establish a stable molten salt circulation loop.

[0051] Step 3: Start the compressor 100. Adjust the opening of the compressor-side heat transfer oil regulating valve 713 to ensure that the heat transfer oil temperature at the shell-side outlet of the compressor-side heat transfer oil-air heat exchanger 510 is maintained at 350℃. Adjust the opening of the compressor-side molten salt regulating valve 711 at the outlet of the low-temperature molten salt tank 320 to ensure that the molten salt temperature at the shell-side outlet of the compressor-side molten salt-heat transfer oil heat exchanger 530 is maintained at 345℃.

[0052] This embodiment discloses an operation method for the molten salt heat exchange system of a compressed air energy storage power station as described in Embodiment 1 or Embodiment 2, applicable to energy release conditions, including the following steps:

[0053] Step 1: Turn on the expansion side heat transfer oil pump 620 and the expansion side heat transfer oil isolation valve 708, and gradually open the expansion side heat transfer oil regulating valve 714 to establish a stable heat transfer oil circulation loop.

[0054] Step 2: Open the expansion side molten salt isolation valve 706 on the outlet side of the high-temperature molten salt tank 310, start the high-temperature molten salt pump 640, and gradually open the expansion side molten salt regulating valve 712 on the outlet side of the high-temperature molten salt tank 310 to establish a stable molten salt circulation loop.

[0055] Step 3: Open the expansion side isolation valve on the gas outlet side of the gas storage tank 400, start the air turbine 200, and ensure that the air temperature at the tube side outlet of the expansion side heat transfer oil-air heat exchanger 520 is maintained at 330℃ by adjusting the opening of the expansion side heat transfer oil regulating valve 714. Ensure that the heat transfer oil temperature at the tube side outlet of the expansion side molten salt-heat transfer oil heat exchanger is maintained at 340℃ by adjusting the opening of the expansion side molten salt regulating valve 712 on the outlet side of the high temperature molten salt tank 310.

[0056] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A molten salt heat exchange system for a compressed air energy storage power station, characterized in that: The system includes a compressor. The high-pressure gas outlet of the compressor is connected to the high-pressure gas inlet of the gas storage tank via a compression-side heat transfer oil-air heat exchanger, a compression-side low-temperature heat exchanger, and a compression-side isolation valve. The high-pressure gas outlet of the gas storage tank is connected to the turbine via an expansion-side isolation valve, an expansion-side low-temperature heat exchanger, and an expansion-side heat transfer oil-air heat exchanger. The shell-side outlet of the compression-side heat transfer oil-air heat exchanger is connected to the tube-side inlet of the compression-side molten salt-heat transfer oil heat exchanger via a compression-side heat transfer oil isolation valve and a compression-side heat transfer oil regulating valve. The tube-side outlet of the compression-side molten salt-heat transfer oil heat exchanger is connected to the inlet of the compression-side heat transfer oil circulating pump. The outlet of the compression-side heat transfer oil circulating pump is connected to the shell-side inlet of the compression-side heat transfer oil-air heat exchanger. The shell-side outlet of the expansion-side heat transfer oil-air heat exchanger... The outlet of the expansion-side heat transfer oil circulation pump is connected in sequence to the inlet of the expansion-side heat transfer oil circulation pump. The outlet of the expansion-side heat transfer oil circulation pump is connected to the shell-side inlet of the expansion-side heat transfer oil-air heat exchanger after passing through the expansion-side molten salt-heat transfer oil heat exchanger, the expansion-side heat transfer oil isolation valve, and the expansion-side heat transfer oil regulating valve. The tube-side outlet of the expansion-side molten salt-heat transfer oil heat exchanger is connected to the inlet of the low-temperature salt pump after passing through the low-temperature salt tank. The outlet of the low-temperature salt pump is connected to the shell-side inlet of the compression-side molten salt-heat transfer oil heat exchanger. The shell-side outlet of the compression-side molten salt-heat transfer oil heat exchanger is connected to the inlet of the high-temperature salt pump after passing through the compression-side molten salt isolation valve, the compression-side molten salt regulating valve, and the high-temperature salt tank. The outlet of the high-temperature salt pump is connected to the tube-side inlet of the expansion-side molten salt-heat transfer oil heat exchanger after passing through the expansion-side heat transfer oil isolation valve and the expansion-side heat transfer oil regulating valve.

2. The molten salt heat exchange system for compressed air energy storage power station according to claim 1, characterized in that: The head of the compression-side heat transfer oil circulation pump and the expansion-side heat transfer oil circulation pump is 48~52m.

3. The molten salt heat exchange system for compressed air energy storage power station according to claim 1, characterized in that: The tube-side outlet of the compression-side molten salt-heat transfer oil heat exchanger and the inlet of the compression-side heat transfer oil circulation pump are connected to the compression-side closed expansion heat transfer oil tank; the shell-side outlet of the expansion-side heat transfer oil-air heat exchanger and the inlet of the expansion-side heat transfer oil circulation pump are connected to the expansion-side closed expansion heat transfer oil tank.

4. The molten salt heat exchange system for compressed air energy storage power station according to claim 3, characterized in that: The volume of the compression-side closed expansion heat transfer oil tank and the expansion-side closed expansion heat transfer oil tank is 8~12m³. 3 .

5. The molten salt heat exchange system for compressed air energy storage power station according to claim 3, characterized in that: The compression-side closed expansion heat transfer oil tank and the expansion-side closed expansion heat transfer oil tank are arranged at a high position. The height difference between the closed expansion heat transfer oil tank and the inlet of the compression-side heat transfer oil circulation pump should be no less than 20m, and the height difference between the expansion-side closed expansion heat transfer oil tank and the inlet of the expansion-side heat transfer oil circulation pump should be no less than 20m.

6. The molten salt heat exchange system for compressed air energy storage power station according to claim 1, characterized in that: The cryogenic salt tank is designed with a pressure of 1.9~2.1MPa and a temperature of 290~310℃.

7. The molten salt heat exchange system for compressed air energy storage power station according to claim 1, characterized in that: The high-temperature salt tank is designed with a pressure of 1.9~2.1MPa and a temperature of 390~410℃.

8. The molten salt heat exchange system for a compressed air energy storage power station according to claim 1, characterized in that: The expansion-side isolation valve includes a first isolation valve on the compression side of the gas storage tank and a second isolation valve on the compression side of the gas storage tank, which are connected in series. The expansion-side isolation valve includes a first isolation valve on the expansion side of the gas storage tank and a second isolation valve on the expansion side of the gas storage tank, which are connected in series.

9. The molten salt heat exchange system for a compressed air energy storage power station according to claim 1, characterized in that: The expansion-side heat transfer oil-air heat exchanger (520) and the compression-side molten salt-heat transfer oil heat exchanger (530) are connected sequentially through the first isolation valve (709) and the second isolation valve (710) of the heat transfer oil interconnection pipeline.

10. A method for operating a molten salt heat exchange system in a compressed air energy storage power station according to any one of claims 1 to 9, characterized in that: When applied to energy storage applications, the following steps are included: Start the compression-side heat transfer oil pump and the compression-side heat transfer oil isolation valve, and gradually open the compression-side heat transfer oil regulating valve to establish a stable heat transfer oil circulation loop. Open the compression side molten salt isolation valve on the outlet side of the cryogenic molten salt tank, start the cryogenic molten salt pump, and gradually open the compression side molten salt regulating valve on the outlet side of the cryogenic molten salt tank to establish a stable molten salt circulation loop. Start the compressor and adjust the opening of the compressor-side heat transfer oil regulating valve to ensure that the outlet temperature of the heat transfer oil on the shell side of the compressor-side heat transfer oil-air heat exchanger is maintained at 350℃. Adjust the opening of the compressor-side molten salt regulating valve on the outlet side of the low-temperature molten salt tank to ensure that the outlet temperature of the molten salt on the shell side of the compressor-side molten salt-heat transfer oil heat exchanger is maintained at 345℃. When applied to energy release conditions, the following steps are included: Start the expansion-side heat transfer oil pump and the expansion-side heat transfer oil isolation valve, and gradually open the expansion-side heat transfer oil regulating valve to establish a stable heat transfer oil circulation loop. Open the expansion side molten salt isolation valve on the outlet side of the high-temperature molten salt tank, start the high-temperature molten salt pump, and gradually open the expansion side molten salt regulating valve on the outlet side of the high-temperature molten salt tank to establish a stable molten salt circulation loop. Open the expansion side isolation valve on the gas outlet side of the gas storage tank, start the air turbine, and ensure that the air temperature at the tube outlet of the expansion side heat transfer oil-air heat exchanger is maintained at 330℃ by adjusting the opening of the expansion side heat transfer oil regulating valve. Ensure that the heat transfer oil temperature at the tube outlet of the expansion side molten salt-heat transfer oil heat exchanger is maintained at 340℃ by adjusting the opening of the expansion side molten salt regulating valve on the outlet side of the high temperature molten salt tank.

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