Compressor combined operation system and method suitable for variable working condition operation of compressed air energy storage system

Abstract

This invention discloses a compressor combined operation system and method suitable for variable operating conditions in compressed air energy storage systems. During the energy storage phase, the flow rate of the centrifugal compressor is determined, and the opening and closing of the air circuit valves are adjusted via a control module. This allows the reciprocating compressor to be activated as a booster device under low flow conditions. When the flow rate is moderate, the centrifugal compressor is used to boost the air pressure. When the flow rate is too high, the centrifugal compressor and the reciprocating compressor are connected in series, with the centrifugal compressor used for initial boosting, followed by further boosting using the reciprocating compressor. Furthermore, the system utilizes a heat exchanger and a heat storage / cooling device to circulate and utilize the waste heat from compression. This invention cleverly combines the applicable operating conditions of reciprocating and centrifugal compressors, integrating their applications without altering any compressor structure. This allows the system to maintain high operating efficiency even under significant energy storage fluctuations.

Description

Technical Field

[0001] This invention belongs to the field of energy storage technology, specifically relating to a compressor combined operation system and method suitable for variable operating conditions of compressed air energy storage systems. Background Technology

[0002] Energy storage technology is urgently needed to address the large-scale integration of renewable energy and improve conventional power systems. It is a supporting technology and strategic emerging technology for the energy revolution, and has received widespread attention from countries around the world. Compressed air energy storage systems have similar costs to pumped hydro storage, but offer large storage capacity, reliable technology, and long operating life. It is one of the most promising development directions in the field of large-scale energy storage and is a crucial means to solve the widespread problems of wind, solar, and hydropower curtailment in my country, achieve peak shaving and valley filling in smart grids, and improve the flexibility of integrated energy systems.

[0003] When storing energy, air is compressed, converting the energy into the potential energy of the air for storage; when releasing energy, the compressed air expands, converting the potential energy into useful work. Therefore, the main components of the system include compressors, expanders, air storage devices, and thermal storage systems. Under current design and manufacturing capabilities, compressor performance has the most significant impact on the overall system performance, and its energy conversion efficiency directly determines the overall system efficiency and economy. Based on different working principles, commonly used compressors in engineering can be broadly classified into reciprocating compressors and centrifugal compressors. Reciprocating compressors are highly efficient and have a wide range of applications, but their piston diameter limits their application to large volumes, making them unsuitable for high-flow-rate compression and primarily used in MW-level compressed air energy storage systems. Centrifugal compressors are suitable for medium to large flow rates, with single-shaft centrifugal compressors suitable for higher discharge pressures and multi-shaft centrifugal compressors suitable for slightly lower discharge pressures, such as 10MW-level compressed air energy storage systems.

[0004] Existing compressed air energy storage systems with large installed capacities (e.g., 10MW to 500MW) typically use centrifugal compressors as gas pressurization devices. However, due to the randomness and volatility of power output from renewable energy sources such as wind and solar power, the amount of electricity available for storage during peak shaving is also highly unstable. When the amount of electricity to be stored is small, the impeller flow within the centrifugal compressor deteriorates, leading to a significant drop in efficiency. In severe cases, surge may occur, causing serious damage to the compressor in a short period and resulting in substantial economic losses. In this situation, centrifugal compressors perform worse than reciprocating compressors. Conversely, when the surplus electricity to be stored is excessive, the flow rate of the centrifugal compressor increases rapidly, and relying solely on centrifugal compressors to pressurize all the gas also results in low compressor system efficiency. Therefore, in compressed air energy storage systems, using centrifugal compressors alone as air pressurization devices is not the most efficient method. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a compressor combined operation system and method suitable for compressed air energy storage systems operating under varying conditions. This invention cleverly combines the operating characteristics applicable to reciprocating compressors and centrifugal compressors, combining the applications of the two compressors without changing any compressor structure. It can be applied to operating conditions with larger installed capacity and can significantly improve the efficiency of the air compression section in compressed air energy storage systems under varying operating conditions, ensuring the safety and stability of the compressor and promoting the efficient and stable operation of the entire system.

[0006] The technical solution adopted in this invention is as follows:

[0007] A compressor combined operation system suitable for variable operating conditions of compressed air energy storage system, including centrifugal compressor, reciprocating compressor, first electromagnetic three-way valve, second electromagnetic three-way valve, air storage tank, expansion work module and waste heat utilization circulation system;

[0008] The first port of the first electromagnetic three-way valve serves as the air inlet. The second port of the first electromagnetic three-way valve is connected to the air inlet of the centrifugal compressor through the first pipeline. The third port of the first electromagnetic three-way valve is connected to the air inlet of the reciprocating compressor through the second pipeline. The air outlet of the reciprocating compressor is connected to the inlet of the gas storage tank.

[0009] The first port of the second electromagnetic three-way valve is connected to the outlet of the centrifugal compressor through the third pipeline, the second port of the second electromagnetic three-way valve is connected to the inlet of the reciprocating compressor through the fourth pipeline, and the third port of the second electromagnetic three-way valve is connected to the inlet of the gas storage tank through the fifth pipeline.

[0010] The expansion work module is connected to the gas storage tank outlet;

[0011] The heat exchange circulation interface of the centrifugal compressor, the heat exchange circulation interface of the reciprocating compressor, and the heat exchange circulation interface of the expansion work module are all connected to the waste heat utilization circulation system.

[0012] Preferably, the compressor combined operation system of the present invention applicable to the variable operating conditions of the compressed air energy storage system further includes a control module, and the first electromagnetic three-way valve and the second electromagnetic three-way valve are both connected to the control module.

[0013] Preferably, an oil-gas separator is installed on the pipeline connecting the outlet of the reciprocating compressor and the inlet of the gas storage tank.

[0014] Preferably, the waste heat utilization circulation system includes a first heat exchanger, a second heat exchanger, a cold accumulator, and a heat accumulator. The heat inlet of the first heat exchanger is connected to the heat exchange circulation outlet of the centrifugal compressor and the heat exchange circulation outlet of the reciprocating compressor, and the cold outlet of the first heat exchanger is connected to the heat exchange circulation inlet of the centrifugal compressor and the heat exchange circulation inlet of the reciprocating compressor.

[0015] The heat outlet of the first heat exchanger is connected to the heat accumulator through a heat transfer medium, and the cold inlet of the first heat exchanger is connected to the cold accumulator through a heat transfer medium.

[0016] The heat inlet of the second heat exchanger is connected to the heat accumulator via a heat transfer medium. The heat outlet of the second heat exchanger is connected to the heat exchange circulation inlet of the expansion work module via a pipeline. The cold outlet of the second heat exchanger is connected to the cold accumulator via a heat transfer medium. The cold inlet of the second heat exchanger is connected to the heat exchange circulation outlet of the expansion work module via a pipeline.

[0017] Preferably, the expansion work module includes an expander.

[0018] Preferably, the expansion work module further includes a generator, which is connected to the expander.

[0019] This invention also provides a compressor combined operation method suitable for variable operating conditions of compressed air energy storage systems. This method is implemented using the compressor combined operation system described above, and includes the following processes:

[0020] Energy storage stage: Use surplus power from the grid to drive centrifugal compressors and reciprocating compressors, and calculate the operating flow rate of the centrifugal compressors;

[0021] When the operating flow rate is less than 30% of the centrifugal compressor's design flow rate, the first electromagnetic three-way valve is controlled to open the intake passage of the reciprocating compressor and close the intake passage of the centrifugal compressor. The first, second, and third ports of the second electromagnetic three-way valve are closed, and the air is compressed and stored in the air storage tank by the reciprocating compressor.

[0022] When the operating flow rate is 70% to 150% of the design flow rate of the centrifugal compressor, the first electromagnetic three-way valve is controlled to open the intake passage of the centrifugal compressor and close the intake passage of the reciprocating compressor. The first and third ports of the second electromagnetic three-way valve are both opened, and the second port of the second electromagnetic three-way valve is closed. The air is compressed by the centrifugal compressor and stored in the air storage tank.

[0023] When the operating flow rate is higher than 150% of the design flow rate of the centrifugal compressor, the first electromagnetic three-way valve is controlled to open the intake passage of the centrifugal compressor and close the intake passage of the reciprocating compressor. At the same time, the second electromagnetic three-way valve is controlled to open the exhaust end passage of the centrifugal compressor to the intake end passage of the reciprocating compressor and close the third port of the second electromagnetic three-way valve, so that the centrifugal compressor and the reciprocating compressor are connected in series. The air is first compressed by the centrifugal compressor to reach the preset pressure and then enters the reciprocating compressor for compression and storage in the air storage tank.

[0024] The waste heat utilization circulation system stores the heat of compression generated during the air compression process of centrifugal compressors and reciprocating compressors;

[0025] Energy release stage: The expansion work module uses compressed air from the gas storage tank to do work. At the same time, the waste heat is used to heat the expansion gas of the expansion work module through the circulation system, and the cold energy generated during the expansion process of the expansion work module is recovered and stored.

[0026] Preferably, the waste heat utilization circulation system includes a first heat exchanger, a second heat exchanger, a cold accumulator, and a heat accumulator. The heat inlet of the first heat exchanger is connected to the heat exchange circulation outlet of the centrifugal compressor and the heat exchange circulation outlet of the reciprocating compressor, and the cold outlet of the first heat exchanger is connected to the heat exchange circulation inlet of the centrifugal compressor and the heat exchange circulation inlet of the reciprocating compressor.

[0027] The heat outlet of the first heat exchanger is connected to the heat accumulator through a heat transfer medium, and the cold inlet of the first heat exchanger is connected to the cold accumulator through a heat transfer medium.

[0028] The heat inlet of the second heat exchanger is connected to the heat accumulator through a heat transfer medium. The heat outlet of the second heat exchanger is connected to the heat exchange circulation inlet of the expansion work module through a pipeline. The cold outlet of the second heat exchanger is connected to the cold accumulator through a heat transfer medium. The cold inlet of the second heat exchanger is connected to the heat exchange circulation outlet of the expansion work module through a pipeline.

[0029] During the energy storage phase, the heat transfer medium stored in the accumulator flows through the first heat exchanger and enters the heat exchange circulation inlet of the reciprocating compressor and the centrifugal compressor, absorbing the heat generated by the compression of the reciprocating compressor and the centrifugal compressor. The heat transfer medium flows out from the heat exchange circulation outlet of the reciprocating compressor and the centrifugal compressor and is stored in the accumulator after passing through the first heat exchanger.

[0030] During the energy release phase, the heat transfer medium stored in the heat accumulator enters the expansion work module after passing through the second heat exchanger to heat the expansion gas. The heat transfer medium after heat exchange then enters the cold accumulator for storage through the heat exchange circulation outlet of the expansion work module and the second heat exchanger.

[0031] The present invention has the following beneficial effects:

[0032] This invention, by setting up a first electromagnetic three-way valve, a second electromagnetic three-way valve, and related pipelines, enables the compression of air using reciprocating compressors and centrifugal compressors, either individually or in series. This invention is applicable to large-scale compressed air energy storage systems ranging from 10MW to 500MW. It cleverly combines the operating characteristics of reciprocating and centrifugal compressors, integrating their applications without altering any compressor structure. When significant changes in operating conditions occur, switching the air path allows the compressor suitable for the current conditions to operate, or a series combination of the two compressors can be formed, significantly improving system efficiency. This invention recovers and stores the heat released by the compressor during the energy storage phase, using it to heat the gas in the expander during the energy release phase. This method both cools the compressor, improving its efficiency, and significantly enhances the expander's operating efficiency, thereby greatly improving the overall energy storage efficiency of the system. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the combined operation system of a compressor for variable operating conditions in an embodiment of the present invention.

[0034] In the diagram: 11-Reciprocating compressor, 111-Oil-gas separator, 12-Centrifugal compressor, 21-Control module, 22-First solenoid three-way valve, 22-1-First pipeline, 22-2-Second pipeline, 23-Second solenoid three-way valve, 23-1-Third pipeline, 23-2-Fourth pipeline, 23-3-Fifth pipeline, 31-First heat exchanger, 32-Second heat exchanger, 33-Cold accumulator, 34-Heat accumulator, 44-Gas storage tank, 55-Expander, 56-Generator. Detailed Implementation

[0035] In the following, specific embodiments of this application will be described in detail with reference to the accompanying drawings. Based on these detailed descriptions, those skilled in the art will be able to clearly understand and implement this application. Without departing from the principles of this application, features from various embodiments can be combined to obtain new implementations, or certain features from some embodiments can be substituted to obtain other preferred implementations.

[0036] In this invention, the terms "larger", "smaller", "higher", "lower", "lower", "lower", "higher", "closer", and "moderate" used to describe flow rate and pressure ratio mainly refer to the fluctuation range compared to the most original design conditions. Those skilled in the art can define the critical transition parameters according to the specific application conditions and environment.

[0037] The low energy conversion efficiency of existing compressed air energy storage systems is mainly due to the use of a single type of compressor unit, which results in low overall compressor unit efficiency when the system faces varying operating conditions. Furthermore, the continuous increase in gas temperature during gas pressurization requires the compressor to consume more compression work, and the heat generated by the compressor is directly dissipated, causing energy loss. In view of this, the present invention provides the following compressor combined operation system and method suitable for compressed air energy storage systems operating under varying conditions.

[0038] like Figure 1 As shown, the system of the present invention mainly includes an energy storage stage device, an energy release stage device, and a compressor waste heat utilization and recycling device.

[0039] The energy storage stage device mainly includes a centrifugal compressor 12, a reciprocating compressor 11, a gas path control module 21, and a first electromagnetic three-way valve 22 and a second electromagnetic three-way valve 23. The left port of the first electromagnetic three-way valve 22 is its first port, serving as the inlet for ambient air. The first electromagnetic three-way valve 22 is connected to the control module 21 via a circuit. The upper and lower ports (i.e., the second and third ports) of the first electromagnetic three-way valve 22 are connected to the air inlets of the centrifugal compressor 12 and the reciprocating compressor 11 respectively via a first pipe 22-1 and a second pipe 22-2. The control module 21 is connected to the second electromagnetic three-way valve 23 via a circuit. The compressed air outlet of the centrifugal compressor 12 is connected to the upper port (i.e., its first port) of the second electromagnetic three-way valve 23 via a third pipe 23-1. The left port (i.e., its second port) of the second electromagnetic three-way valve 23 is connected to the inlet of the reciprocating compressor 11 via the fourth pipe 23-2, and the lower port (i.e., its third port) of the second electromagnetic three-way valve 23 is connected to the inlet of the air storage tank 44 via the fifth pipe 23-3. The compressed air outlet of the reciprocating compressor 11 is connected to the inlet of the air storage tank 44 via a pipe, and an oil-gas separator 111 is installed on this pipe.

[0040] The energy release stage device mainly consists of a gas storage tank 44, an expander 55, and a generator 56. The gas storage tank 44 is connected to the gas inlet of the expander 55 via a pipeline, and the gas outlet of the expander 55 is directly connected to the atmosphere. The expander 55 is connected to the generator 56 via a line.

[0041] The compressor waste heat recovery circulation device mainly consists of a first heat exchanger 31, a second heat exchanger 32, a cold accumulator 33, and a heat accumulator 34. The upper inlet (i.e., its hot inlet) of the first heat exchanger 31 is connected via a pipeline to the heat exchange circulation outlet of the reciprocating compressor 11 and the heat exchange circulation outlet of the centrifugal compressor 12. The right-side outlet (i.e., its cold outlet) of the first heat exchanger 31 is connected via a pipeline to the heat exchange circulation inlet of the reciprocating compressor 11 and the heat exchange circulation inlet of the centrifugal compressor 12. The lower outlet (i.e., its hot outlet) of the first heat exchanger 31 is connected to the heat accumulator 34 via a heat transfer medium. The left-side inlet (i.e., its cold inlet) of the first heat exchanger 31 is connected to the cold accumulator 33 via a heat transfer medium. The right-side inlet (i.e., its cold inlet) of the second heat exchanger 32 is connected via a pipeline to the heat exchange circulation outlet of the expander 55. The lower outlet (i.e., its hot outlet) of the second heat exchanger 32 is connected via a pipeline to the heat exchange circulation inlet of the expander 55. The outlet on the left side of the second heat exchanger 32 (i.e. its cold outlet) is connected to the cold storage 33 through a heat transfer medium, and the inlet above the second heat exchanger 32 (i.e. its hot inlet) is connected to the cold storage 34 through a heat transfer medium.

[0042] This invention relates to a method for combined operation of compressors in compressed air energy storage systems operating under varying conditions. The specific implementation process is as follows:

[0043] Energy storage stage: The surplus electricity generated by distributed new energy sources such as wind and solar power input into the grid is used to calculate the operating flow rate of centrifugal compressor 12 based on the input power of the motor driving the compressor and parameters such as the filling time and volumetric flow rate of gas storage tank 44.

[0044] When the calculated operating flow rate is less than 30% of the design flow rate of the centrifugal compressor 12, the control module 21 controls the first electromagnetic three-way valve 22 to open the intake passage of the reciprocating compressor 11 and close the intake passage of the centrifugal compressor 12. The control module 21 controls the second electromagnetic three-way valve 23 to close the first port, the second port and the third port of the second electromagnetic three-way valve 23, so that the ambient air enters the reciprocating compressor 11 for pressurization, then enters the oil-gas separator 111 to remove the lubricating oil, and then enters the gas storage tank 44 for storage.

[0045] When the calculated operating flow rate is 70% to 150% of the design flow rate of the centrifugal compressor 12, the control module 21 controls the first electromagnetic three-way valve 22 to open the intake passage of the centrifugal compressor 12 and close the intake passage of the reciprocating compressor 11. At the same time, the control module 21 controls the second electromagnetic three-way valve 23 to open the first port and the third port and close the second port, so that the ambient air enters the centrifugal compressor 12 for pressurization and enters the air storage tank 44 for storage.

[0046] When the calculated operating flow rate is higher than 150% of the design flow rate of the centrifugal compressor 12, the control module 21 controls the first electromagnetic three-way valve 22 to open the intake passage of the centrifugal compressor 12 and close the intake passage of the reciprocating compressor 11. At the same time, the control module 21 controls the second electromagnetic three-way valve 23 to open the exhaust end of the centrifugal compressor 12 to the intake passage of the reciprocating compressor 11 and close the gas passage of the second electromagnetic three-way valve 23 directly to the gas storage tank 44 (i.e., close the third port of the second electromagnetic three-way valve 23), forming a series passage between the centrifugal compressor 12 and the reciprocating compressor 11. This allows air to first enter the centrifugal compressor 12 for compression, and after reaching a certain pressure, it enters the reciprocating compressor 11 to complete the gas pressurization process. After that, it is purified by the oil-gas separator 111 and enters the gas storage tank 44 for storage until the entire energy storage process is completed.

[0047] During the energy release phase, the high-pressure gas in the gas storage tank 44 flows out and enters the expander 55 to do work, driving the generator 56 to generate electricity, which is then fed into the user's power grid.

[0048] During the energy storage phase, the centrifugal compressor 12 and reciprocating compressor 11 generate a large amount of compression heat during operation. The centrifugal compressor 12 and reciprocating compressor 11 are cooled by the first heat exchanger 31 to improve the efficiency of the compressors, and the absorbed compression heat is stored in the heat accumulator 34. During the energy release phase, the high-pressure gas generates a large amount of cold energy when it does work in the expander 55. The heat stored in the heat accumulator 34 is used to heat the expanded gas through the second heat exchanger 32 to improve the efficiency of the expander 55. The cold energy generated during the expansion process is recovered by the second heat exchanger 32 and stored in the cold accumulator 33 to cool the centrifugal compressor 12 and reciprocating compressor 11 operating during the energy storage phase.

[0049] As can be seen from the above scheme, in the energy storage stage, the surplus electricity generated by distributed new energy sources such as wind and solar power input into the power grid can be controlled by the control module to open and close the first and second electromagnetic three-way valves, thus forming a combined form of the compressor that is adapted to the operating conditions.

Claims

1. A compressor combined operation system suitable for variable operating conditions of compressed air energy storage systems, characterized in that, It includes a reciprocating compressor (11), a centrifugal compressor (12), a first electromagnetic three-way valve (22), a second electromagnetic three-way valve (23), a gas storage tank (44), an expansion work module, and a waste heat utilization circulation system; The first port of the first electromagnetic three-way valve (22) serves as the air inlet. The second port of the first electromagnetic three-way valve (22) is connected to the air inlet of the centrifugal compressor (12) through the first pipeline (22-1). The third port of the first electromagnetic three-way valve (22) is connected to the air inlet of the reciprocating compressor (11) through the second pipeline (22-2). The air outlet of the reciprocating compressor (11) is connected to the inlet of the gas storage tank (44). The first port of the second electromagnetic three-way valve (23) is connected to the outlet of the centrifugal compressor (12) through the third pipeline (23-1), the second port of the second electromagnetic three-way valve (23) is connected to the inlet of the reciprocating compressor (11) through the fourth pipeline (23-2), and the third port of the second electromagnetic three-way valve (23) is connected to the inlet of the gas storage tank (44) through the fifth pipeline (23-3); The expansion work module is connected to the outlet of the gas storage tank (44); The heat exchange circulation interface of the centrifugal compressor (12), the heat exchange circulation interface of the reciprocating compressor (11) and the heat exchange circulation interface of the expansion work module are all connected to the waste heat utilization circulation system. The compressor joint operation process applicable to the variable operating conditions of the compressed air energy storage system is as follows: Energy storage stage: The surplus power of the power grid is used to drive the reciprocating compressor (11) and the centrifugal compressor (12) to work, and the operating flow of the centrifugal compressor (12) is calculated; When the operating flow rate is less than 30% of the design flow rate of the centrifugal compressor (12), the first electromagnetic three-way valve (22) is controlled to open the intake passage of the reciprocating compressor (11), close the intake passage of the centrifugal compressor (12), and close the first, second and third ports of the second electromagnetic three-way valve (23). The air is compressed by the reciprocating compressor (11) and stored in the air storage tank (44). When the operating flow rate is 70% to 150% of the design flow rate of the centrifugal compressor (12), the first electromagnetic three-way valve (22) is controlled to open the intake passage of the centrifugal compressor (12) and close the intake passage of the reciprocating compressor (11). The first and third ports of the second electromagnetic three-way valve (23) are both opened, and the second port of the second electromagnetic three-way valve (23) is closed. The air is compressed by the centrifugal compressor (12) and stored in the air storage tank (44). When the operating flow rate is higher than 150% of the design flow rate of the centrifugal compressor (12), the first electromagnetic three-way valve (22) is controlled to open the intake passage of the centrifugal compressor (12) and close the intake passage of the reciprocating compressor (11). At the same time, the second electromagnetic three-way valve (23) is controlled to open the exhaust end passage of the centrifugal compressor (12) to the intake end passage of the reciprocating compressor (11) and close the third port of the second electromagnetic three-way valve (23), so that the centrifugal compressor (12) and the reciprocating compressor (11) are connected in series. The air is first compressed by the centrifugal compressor (12) and reaches the preset pressure before entering the reciprocating compressor (11) for compression and storage in the air storage tank (44). The waste heat utilization circulation system stores the heat of compression generated during the air compression process of the centrifugal compressor (12) and the reciprocating compressor (11); Energy release stage: The expansion work module uses compressed air in the gas storage tank (44) to do work. At the same time, the waste heat is used to heat the expansion gas of the expansion work module through the circulation system, and the cold energy generated during the expansion process of the expansion work module is recovered and stored.

2. The compressor combined operation system for variable operating conditions of compressed air energy storage systems according to claim 1, characterized in that, It also includes a control module (21), and the first electromagnetic three-way valve (22) and the second electromagnetic three-way valve (23) are both connected to the control module (21).

3. The compressor combined operation system for variable operating conditions of compressed air energy storage systems according to claim 1, characterized in that, An oil-gas separator (111) is installed on the pipeline connecting the outlet of the reciprocating compressor (11) and the inlet of the gas storage tank (44).

4. The compressor combined operation system for variable operating conditions of compressed air energy storage systems according to claim 1, characterized in that, The waste heat utilization circulation system includes a first heat exchanger (31), a second heat exchanger (32), a cold storage (33) and a heat storage (34). The heat inlet of the first heat exchanger (31) is connected to the heat exchange circulation outlet of the centrifugal compressor (12) and the heat exchange circulation outlet of the reciprocating compressor (11). The cold outlet of the first heat exchanger (31) is connected to the heat exchange circulation inlet of the centrifugal compressor (12) and the heat exchange circulation inlet of the reciprocating compressor (11). The heat outlet of the first heat exchanger (31) is connected to the heat accumulator (34) through a heat transfer medium, and the cold inlet of the first heat exchanger (31) is connected to the cold accumulator (33) through a heat transfer medium. The heat inlet of the second heat exchanger (32) is connected to the heat storage unit (34) through a heat transfer medium. The heat outlet of the second heat exchanger (32) is connected to the heat exchange circulation inlet of the expansion work module through a pipeline. The cold outlet of the second heat exchanger (32) is connected to the cold storage unit (33) through a heat transfer medium. The cold inlet of the second heat exchanger (32) is connected to the heat exchange circulation outlet of the expansion work module through a pipeline.

5. The compressor combined operation system for variable operating conditions of compressed air energy storage systems according to claim 1, characterized in that, The expansion work module includes an expander (55).

6. The compressor combined operation system for variable operating conditions of compressed air energy storage systems according to claim 5, characterized in that, The expansion power module also includes a generator (56), which is connected to the expander (55).

7. A method for combined operation of compressors applicable to compressed air energy storage systems operating under varying conditions, characterized in that, This method is implemented using a compressor combined operation system as described in any one of claims 1-6, suitable for variable operating conditions of compressed air energy storage systems, and includes the following processes: Energy storage stage: The surplus power of the power grid is used to drive the reciprocating compressor (11) and the centrifugal compressor (12) to work, and the operating flow of the centrifugal compressor (12) is calculated; When the operating flow rate is less than 30% of the design flow rate of the centrifugal compressor (12), the first electromagnetic three-way valve (22) is controlled to open the intake passage of the reciprocating compressor (11), close the intake passage of the centrifugal compressor (12), and close the first, second and third ports of the second electromagnetic three-way valve (23). The air is compressed by the reciprocating compressor (11) and stored in the air storage tank (44). When the operating flow rate is 70% to 150% of the design flow rate of the centrifugal compressor (12), the first electromagnetic three-way valve (22) is controlled to open the intake passage of the centrifugal compressor (12) and close the intake passage of the reciprocating compressor (11). The first and third ports of the second electromagnetic three-way valve (23) are both opened, and the second port of the second electromagnetic three-way valve (23) is closed. The air is compressed by the centrifugal compressor (12) and stored in the air storage tank (44). When the operating flow rate is higher than 150% of the design flow rate of the centrifugal compressor (12), the first electromagnetic three-way valve (22) is controlled to open the intake passage of the centrifugal compressor (12) and close the intake passage of the reciprocating compressor (11). At the same time, the second electromagnetic three-way valve (23) is controlled to open the exhaust end passage of the centrifugal compressor (12) to the intake end passage of the reciprocating compressor (11) and close the third port of the second electromagnetic three-way valve (23), so that the centrifugal compressor (12) and the reciprocating compressor (11) are connected in series. The air is first compressed by the centrifugal compressor (12) and reaches the preset pressure before entering the reciprocating compressor (11) for compression and storage in the air storage tank (44). The waste heat utilization circulation system stores the heat of compression generated during the air compression process of the centrifugal compressor (12) and the reciprocating compressor (11); Energy release stage: The expansion work module uses compressed air in the gas storage tank (44) to do work. At the same time, the waste heat is used to heat the expansion gas of the expansion work module through the circulation system, and the cold energy generated during the expansion process of the expansion work module is recovered and stored.

8. The compressor joint operation method for compressed air energy storage systems under varying operating conditions, as described in claim 7, is characterized in that... The waste heat utilization circulation system includes a first heat exchanger (31), a second heat exchanger (32), a cold storage (33) and a heat storage (34). The heat inlet of the first heat exchanger (31) is connected to the heat exchange circulation outlet of the centrifugal compressor (12) and the heat exchange circulation outlet of the reciprocating compressor (11). The cold outlet of the first heat exchanger (31) is connected to the heat exchange circulation inlet of the centrifugal compressor (12) and the heat exchange circulation inlet of the reciprocating compressor (11). The heat outlet of the first heat exchanger (31) is connected to the heat accumulator (34) through a heat transfer medium, and the cold inlet of the first heat exchanger (31) is connected to the cold accumulator (33) through a heat transfer medium. The heat inlet of the second heat exchanger (32) is connected to the heat storage unit (34) through a heat transfer medium. The heat outlet of the second heat exchanger (32) is connected to the heat exchange circulation inlet of the expansion work module through a pipeline. The cold outlet of the second heat exchanger (32) is connected to the cold storage unit (33) through a heat transfer medium. The cold inlet of the second heat exchanger (32) is connected to the heat exchange circulation outlet of the expansion work module through a pipeline. During the energy storage stage, the heat transfer medium stored in the cold storage (33) flows through the first heat exchanger (31) and enters the heat exchange circulation inlet of the reciprocating compressor (11) and the centrifugal compressor (12) to absorb the heat generated by the compression of the reciprocating compressor (11) and the centrifugal compressor (12). The heat transfer medium flows out from the heat exchange circulation outlet of the reciprocating compressor (11) and the centrifugal compressor (12) and is stored in the heat storage (34) after passing through the first heat exchanger (31). During the energy release phase, the heat transfer medium stored in the heat accumulator (34) enters the expansion work module after passing through the second heat exchanger (32) to heat the expansion gas. After heat exchange, the heat transfer medium enters the cold accumulator (33) for storage through the heat exchange circulation outlet of the expansion work module and the second heat exchanger (32).

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