A compressed air energy storage preheating system and method

Abstract

This invention discloses a compressed air energy storage preheating system and method, belonging to the field of compressed air energy storage technology. The system includes a compression module, an air storage unit, an expansion power generation module, a heat storage and release module, and a preheating control unit connected in sequence. The preheating control unit includes a preheating air source branch, a staged preheating component, a regenerative branch, and an interlocking control component. The preheating air source branch is connected to the compressor outlet. The staged preheating component is arranged in the order of shaft seal, expander body, and inlet pipe. The regenerative branch connects the inlet pipe preheating unit and the compressor inlet. This invention utilizes the compressor's waste heat during the compression stage to achieve staged preheating, eliminating the need for an additional heat source, shortening the expander start-up time, improving the grid dispatch response speed, and simultaneously recovering the preheating working fluid and waste heat, reducing system losses, and is suitable for large-capacity compressed air energy storage systems.

Description

Technical Field

[0001] This invention relates to the field of compressed air energy storage technology, and in particular to a compressed air energy storage preheating system and method. Background Technology

[0002] With the rapid construction of new power systems, energy storage technology has ushered in large-scale development. Among them, non-combustion compressed air energy storage systems have become an important development direction for new energy storage due to their advantages of large capacity, long duration, environmental friendliness, and low total life cycle cost. They are also constantly iterating and upgrading towards larger capacity and higher parameters.

[0003] In non-combustion compressed air energy storage systems, during long-term shutdowns, the temperatures of the connecting pipes from the gas storage tank outlet to the expander inlet, and the connecting pipes between each stage of the expander, gradually decrease to ambient temperature over time. The temperatures of the expander body and shaft sealing system also drop to ambient temperature simultaneously. Therefore, during the unit startup phase, a complete preheating process is required, involving the pipes, expander body, and shaft sealing system. Compressed air can only be introduced to perform work after all components reach the required operating temperatures. This lengthy preheating process results in slow response times to grid dispatch, hindering the unit's ability to quickly participate in grid peak shaving and frequency regulation, and limiting the dispatch flexibility of the compressed air energy storage system.

[0004] To address the aforementioned shortcomings, existing technologies have not yet proposed a perfect solution. Conventional designs cannot achieve efficient preheating before unit startup, nor can they solve the problem of no preheating heat source in the initial stage of pure power generation operation, making it difficult to meet the needs of large-capacity compressed air energy storage systems for rapid response to grid dispatch. Summary of the Invention

[0005] To address the technical problems of existing non-combustion compressed air energy storage systems, such as long preheating processes after shutdown, slow unit startup, poor grid dispatch response speed, and lack of preheating heat sources in the initial stage of pure power generation, this invention provides a compressed air energy storage preheating system and method. During the compression energy storage stage, the compression heat at the compressor outlet is used as a heat source. A staged preheating process completes the preheating of the entire system on the expander side, eliminating the need for an additional heat source, shortening expander startup time, improving grid dispatch response speed, and simultaneously achieving efficient recovery of the working fluid and waste heat, ensuring system operating efficiency.

[0006] The technical solution adopted by the compressed air energy storage preheating system and method of the present invention is as follows: A compressed air energy storage preheating system includes a compression module, a gas storage unit, an expansion power generation module, and a heat storage and release module coupled to the compression module and the expansion power generation module, connected in sequence; it also includes a preheating control unit, which includes a preheating gas source branch, a staged preheating component, a regenerative branch, and an interlocking control component; wherein, the inlet end of the preheating gas source branch is connected to the compressor outlet of the compression module, and the outlet end of the preheating gas source branch is connected to each preheating unit of the staged preheating component, for supplying pressurized hot air generated during compression as a preheating gas source to the staged preheating component; The staged preheating assembly includes a shaft seal preheating unit, an expander body preheating unit, and an inlet pipe preheating unit arranged sequentially along the preheating process. These units are used to perform staged preheating of the shaft seal system, expander body, and expander inlet pipe of the expansion power generation module, respectively. The inlet end of the regenerative branch is connected to the outlet end of the inlet pipe preheating unit, and the outlet end is connected to the compressor inlet of the compression module, for recovering the preheated working fluid and waste heat. The interlocking control assembly is connected to the valve assembly of each preheating unit and the preheating gas source branch of the staged preheating assembly, for regulating the on / off state and flow rate of the preheating gas source according to the preheating temperature.

[0007] A further improvement of the technical solution of the present invention is that: the compression module includes at least two air compressors connected in series, and the outlet of each air compressor is provided with a cooling heat exchanger connected to the heat storage and release module; the inlet end of the preheating gas source branch is connected to the outlet of the first air compressor, and the connection position is located upstream of the cooling heat exchanger corresponding to the first air compressor.

[0008] A further improvement of the technical solution of the present invention is that: the expansion power generation module includes at least two stages of air expanders connected in series, and each stage of air expander is provided with a heating heat exchanger connected to the heat storage and release module at its inlet; the shaft seal preheating unit is connected to the shaft seal steam supply station of each stage of air expander, the expander body preheating unit is connected to the internal flow channel of the cylinder of each stage of air expander, and the inlet pipe preheating unit is connected to the inlet pipe of each stage of air expander, and the connection position is located downstream of the corresponding heating heat exchanger.

[0009] A further improvement of the technical solution of the present invention is that: a gas source shut-off valve is provided on the main pipeline of the preheating gas source branch; a flow regulating valve is provided on the air inlet branch of the shaft seal preheating unit, the expander body preheating unit, and the inlet pipeline preheating unit; and a recirculation shut-off valve is provided on the reheating branch.

[0010] A further improvement of the technical solution of the present invention is that: the interlocking control component includes a temperature detection element and a controller; wherein, the temperature detection element is respectively installed at the shaft sealing system, the expander body, and the expander inlet pipe of the expansion power generation module, for real-time acquisition of preheating temperature; the signal input terminal of the controller is connected to the temperature detection element, and the signal output terminal is respectively connected to the gas source shut-off valve, each flow regulating valve, and the return shut-off valve, for interlocking and controlling the opening and closing of the corresponding valves according to the comparison result of the acquired preheating temperature and the preset threshold.

[0011] A further improvement of the technical solution of the present invention is that: the heat storage and release module includes a cold water tank, a hot water tank, a cold water pump, and a hot water pump; wherein, the cold water tank is connected to the cold side inlet of each stage of the cooling heat exchanger of the compression module through the cold water pump, and the cold side outlet of each stage of the cooling heat exchanger is connected to the hot water tank; the hot water tank is connected to the hot side inlet of each stage of the heating heat exchanger of the expansion power generation module through the hot water pump, and the hot side outlet of each stage of the heating heat exchanger is connected to the cold water tank.

[0012] A compressed air energy storage preheating method, using the aforementioned preheating system, includes the following steps: During the compressed energy storage phase when the electricity load is low, the compression module is started and running, while the expansion generator module is shut down; the preheating gas source branch is opened, and the pressurized hot air from the compressor outlet of the compression module is used as the preheating gas source, and the preheating is completed in stages in the order of first the shaft seal system, then the expander body, and finally the expander inlet pipe; during the preheating process, the preheating temperature is collected in real time through an interlocking control component, and the flow rate of the preheating gas source is dynamically adjusted according to the preheating temperature; after the inlet pipe is preheated, the preheated working fluid flows back to the compressor inlet of the compression module through the reheating branch, completing the recovery of the working fluid and waste heat.

[0013] A further improvement of the above technical solution of the present invention is that the start time of the staged preheating is the last 1 / 3 to 1 / 4 of the compression energy storage stage.

[0014] A further improvement of the above-mentioned technical solution of the present invention is that: during each stage of preheating, when the preheating temperature of the corresponding part reaches the minimum temperature requirement for the expansion machine to be put into operation, the air intake branch of the corresponding preheating unit is closed to complete the preheating of that stage.

[0015] A further improvement of the above technical solution of the present invention is that when the initial temperature of each part of the expansion power generation module to be preheated is higher than the minimum temperature requirement for commissioning, the preheating gas source branch and the regeneration branch are closed, and all the air compressed by the compression module enters the gas storage unit for storage.

[0016] The technological advancements achieved by this invention due to the adoption of the above technical solutions are as follows: This invention, by setting up a preheating control unit, directly extracts pressurized hot air from the compressor outlet as a preheating gas source during the compression energy storage stage, eliminating the need for additional auxiliary heat sources such as electric heating or steam heating. This solves the problem of no preheating heat source in the initial stage of pure power generation operation of the energy storage power station. At the same time, it completes the entire process preheating on the expander side before the unit starts up, shortens the expander start-up and commissioning time, improves the unit's response speed to grid dispatch, and enhances the dispatch flexibility of the compressed air energy storage system.

[0017] This invention adopts a staged preheating sequence of shaft seal system → expander body → inlet pipe, which matches the start-up temperature rise logic of the expander. This can avoid damage to components such as expander rotor, cylinder, and shaft seal caused by alternating hot and cold shocks, ensuring the safety and stability of the preheating process. At the same time, the staged preheating mode can achieve independent and precise temperature control of each part, improving preheating efficiency.

[0018] This invention, through the interlocking control structure of temperature detection element and flow regulating valve, can provide real-time feedback on temperature changes in the preheating part, dynamically adjust the flow rate of preheating gas source, accurately control the temperature rise rate and target preheating temperature, match the commissioning temperature requirements given by the expander manufacturer, and avoid problems of insufficient or overheating.

[0019] This invention, by setting up a regenerative branch, recovers the preheated working fluid and waste heat from the inlet pipe to the compressor inlet, thereby minimizing working fluid loss and heat loss during the preheating process and improving the overall energy utilization efficiency of the compressed air energy storage system.

[0020] The system structure of this invention can be adapted to large-capacity, high-parameter compressed air energy storage systems with multi-stage compression and multi-stage expansion, and has a wide range of applications. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of a compressed air energy storage preheating system according to the present invention.

[0022] In the attached diagram: 1. First air compressor; 2. Second air compressor; 3. First heat exchanger; 4. Second heat exchanger; 5. Hot water tank; 6. Cold water tank; 7. Hot water pump; 8. Cold water pump; 9. Third heat exchanger; 10. Fourth heat exchanger; 11. First air expander; 12. Second air expander; 13. First shaft seal steam supply station; 14. Second shaft seal steam supply station; v1. Air source shut-off valve; v2. Recirculation shut-off valve; v3. First expander inlet shut-off valve; v4. First expander outlet check valve; v5. Second expander inlet shut-off valve; v6. Second expander outlet check valve; v7. First inlet pipe preheating regulating valve; v8. First shaft seal preheating regulating valve; v9. First body preheating regulating valve; v10. Second inlet pipe preheating regulating valve; v11. Second shaft seal preheating regulating valve; v12. Second body preheating regulating valve. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings. In the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily obscuring the concept of this invention. Example 1

[0024] like Figure 1 As shown, this embodiment provides a compressed air energy storage preheating system, including a compression module, an air storage unit, an expansion power generation module connected in sequence, and a heat storage and release module coupled to the compression module and the expansion power generation module, and also includes a preheating control unit.

[0025] The compression module includes a first air compressor 1 and a second air compressor 2 connected in series, with the outlet of the first air compressor 1 connected to the inlet of the second air compressor 2; the outlet of the first air compressor 1 is provided with a first heat exchanger 3 (cooling heat exchanger), and the outlet of the second air compressor 2 is provided with a second heat exchanger 4 (cooling heat exchanger). Both the first heat exchanger 3 and the second heat exchanger 4 are shell-and-tube heat exchangers used to recover the heat of compression generated during the air compression process.

[0026] The heat storage and release module includes a cold water tank 6, a hot water tank 5, a cold water pump 8, and a hot water pump 7. The outlet of the cold water tank 6 is connected to the cold side inlet of the first heat exchanger 3 and the second heat exchanger 4 through the cold water pump 8. The cold side outlets of the first heat exchanger 3 and the second heat exchanger 4 are combined into one pipeline, which is connected to the inlet of the hot water tank 5. The outlet of the hot water tank 5 is connected to the hot side inlet of the third heat exchanger 9 and the fourth heat exchanger 10 through the hot water pump 7. The hot side outlets of the third heat exchanger 9 and the fourth heat exchanger 10 are combined into one pipeline, which is connected to the inlet of the cold water tank 6.

[0027] The expansion power generation module includes a first air expander 11 and a second air expander 12 connected in series. The outlet of the first air expander 11 is connected to the inlet of the second air expander 12. A third heat exchanger 9 (heating heat exchanger) is installed at the inlet of the first air expander 11, and a fourth heat exchanger 10 (heating heat exchanger) is installed at the inlet of the second air expander 12. Both the third heat exchanger 9 and the fourth heat exchanger 10 are shell-and-tube heat exchangers used to heat the high-pressure air during the expansion stage. A first expander inlet shut-off valve v3 is installed on the inlet pipe of the first air expander 11, and a first expander outlet check valve v4 is installed on the outlet pipe. A second expander inlet shut-off valve v5 is installed on the inlet pipe of the second air expander 12, and a second expander outlet check valve v6 is installed on the outlet pipe. The first air expander 11 is equipped with a first shaft seal steam supply station 13, and the second air expander 12 is equipped with a second shaft seal steam supply station 14, used to provide sealing air source for the expander shaft seal system.

[0028] In this embodiment, the preheating control unit includes a preheating gas source branch, a staged preheating component, a regeneration branch, and an interlocking control component.

[0029] The preheating air source branch uses a DN100 preheating pipe, whose inlet end is connected to the outlet of the first air compressor 1, and the connection position is located upstream of the first heat exchanger 3. An air source shut-off valve v1 is installed on the main pipe; the outlet end of the preheating air source branch is connected to each preheating unit of the staged preheating component.

[0030] The staged preheating assembly includes a shaft seal preheating unit, an expander body preheating unit, and an inlet pipe preheating unit arranged sequentially along the preheating process.

[0031] The shaft seal preheating unit includes two DN80 intake branch pipes, which are led out from the main pipeline of the preheating gas source branch. One pipe is connected to the first shaft seal steam supply station 13, and the pipeline is equipped with the first shaft seal preheating regulating valve v8; the other pipe is connected to the second shaft seal steam supply station 14, and the pipeline is equipped with the second shaft seal preheating regulating valve v11.

[0032] The expander body preheating unit includes two DN80 air inlet branch pipes, which are respectively led out from the main pipeline of the preheating air source branch. One of them is connected to the outlet pipeline of the first air expander 11, and the connection position is located upstream of the outlet check valve v4 of the first expander. The pipeline is equipped with the first body preheating regulating valve v9; the other is connected to the outlet pipeline of the second air expander 12, and the connection position is located upstream of the outlet check valve v6 of the second expander. The pipeline is equipped with the second body preheating regulating valve v12.

[0033] The inlet pipe preheating unit includes two DN80 air inlet branch pipes, which are respectively led out from the main pipe of the preheating air source branch. One branch pipe is connected to the inlet pipe of the first air expander 11, and the connection point is located downstream of the third heat exchanger 9 and upstream of the first expander inlet shut-off valve v3. A first inlet pipe preheating regulating valve v7 is installed on the pipe. The other branch pipe is connected to the inlet pipe of the second air expander 12, and the connection point is located downstream of the fourth heat exchanger 10 and upstream of the second expander inlet shut-off valve v5. A second inlet pipe preheating regulating valve v10 is installed on the pipe.

[0034] The regenerative branch uses a DN80 regenerative pipe, with its inlet end leading out from the upstream of the first expander inlet shut-off valve v3 and the upstream of the second expander inlet shut-off valve v5, respectively. The two lines are combined and connected to the inlet pipe of the first air compressor 1. A recirculation shut-off valve v2 is installed on the regenerative branch.

[0035] The interlocking control component includes thermocouples (temperature sensors) and a PLC controller. The thermocouples are respectively installed at the first shaft seal steam supply station 13, the second shaft seal steam supply station 14, the cylinder of the first air expander 11, the cylinder of the second air expander 12, the inlet pipe of the first air expander 11, and the inlet pipe of the second air expander 12, for real-time acquisition of the preheating temperature of the corresponding parts. The signal input terminal of the PLC controller is connected to each thermocouple, and the signal output terminal is electrically connected to the gas source shut-off valve v1, the return shut-off valve v2, and each flow regulating valve, for interlocking and controlling the opening and closing of the corresponding valves according to the acquired temperature data. Example 2

[0036] This embodiment provides a compressed air energy storage preheating method, based on the system implementation of Embodiment 1, and the specific steps are as follows: S1. During the compression and energy storage phase when the power load is low, the surplus power from the power grid drives the first air compressor 1 and the second air compressor 2 to operate, while the first air expander 11 and the second air expander 12 are in a stopped state. The first expander inlet shut-off valve v3, the second expander inlet shut-off valve v5, the first expander outlet check valve v4, and the second expander outlet check valve v6 are all in a closed state. During the last 1 / 3 of the compression and energy storage phase, the air source shut-off valve v1 and the return shut-off valve v2 are opened to start the preheating process.

[0037] S2. Shaft seal system preheating: Open the first shaft seal preheating regulating valve v8 and the second shaft seal preheating regulating valve v11. The pressurized hot air from the outlet of the first air compressor 1 enters the first shaft seal steam supply station 13 and the second shaft seal steam supply station 14 through the preheating air source branch to preheat the shaft seal system of the two-stage expander. The air after releasing heat is discharged through the shaft seal overflow system. During the preheating process, the thermocouple collects the shaft seal system temperature in real time. The PLC controller compares the collected temperature with the preset shaft seal commissioning temperature threshold and dynamically adjusts the opening of v8 and v11 to control the temperature rise rate to match the requirements of the expander. When the shaft seal system temperature reaches the commissioning requirements, v8 and v11 are closed to complete the shaft seal system preheating.

[0038] S3. Preheating of the expander body: After the shaft seal system is preheated, the first body preheating regulating valve v9 and the second body preheating regulating valve v12 are opened. Pressurized hot air enters the cylinder of the first air expander 11 and the second air expander 12 through the preheating air source branch to warm up the cylinder and rotor. The air after releasing heat is discharged through the exhaust system of the expander body. During the preheating process, the opening of v9 and v12 is dynamically adjusted through the interlocking control of thermocouple and PLC controller. When the temperature of the expander body reaches the commissioning requirements, v9 and v12 are closed to complete the preheating of the expander body.

[0039] S4. Preheating of the expander inlet pipe: After the expander body is preheated, open the first inlet pipe preheating regulating valve v7 and the second inlet pipe preheating regulating valve v10. Pressurized hot air enters the inlet pipes of the first air expander 11 and the second air expander 12 through the preheating air source branch, respectively, to preheat the pipes between the third heat exchanger 9 and the first expander inlet shut-off valve v3, and between the fourth heat exchanger 10 and the second expander inlet shut-off valve v5. The preheated low-temperature air flows back to the inlet of the first air compressor 1 through the heat recovery branch, completing the recovery of working fluid and waste heat. During the preheating process, the opening of v7 and v10 is dynamically adjusted through interlock control. When the inlet pipe temperature reaches the commissioning requirements, v7 and v10 are closed to complete the inlet pipe preheating.

[0040] S5. After the entire process preheating is completed, close the gas source shut-off valve v1 and the return shut-off valve v2. All the high-pressure air compressed by the compression module enters the gas storage unit for storage. If the unit shutdown time is short and the initial temperature of each part of the expander is higher than the minimum operating temperature requirement, there is no need to start the preheating process. Directly close the gas source shut-off valve v1 and the return shut-off valve v2. All the air compressed by the compression module enters the gas storage unit for storage.

[0041] After the preheating process is completed, when the power grid is in peak electricity demand and the unit needs to start generating electricity, the first expander inlet shut-off valve v3 and the second expander inlet shut-off valve v5 can be opened directly. The high-pressure air in the gas storage unit is heated and then enters the expander to do work, eliminating the need for preheating operations, shortening the unit start-up time, and achieving a rapid response to power grid dispatch.

[0042] In the above embodiments, a compressed air energy storage preheating system and method are provided. This invention, by setting up a preheating control unit, directly extracts pressurized hot air from the compressor outlet as the preheating gas source during the compressed energy storage stage, eliminating the need for additional auxiliary heat sources such as electric heating or steam heating. This solves the problem of no preheating heat source in the initial stage of pure power generation operation of the energy storage power station. Simultaneously, it completes the entire process preheating on the expander side before unit startup, shortening the expander startup and commissioning time, improving the unit's response speed to grid dispatch, and enhancing the dispatch flexibility of the compressed air energy storage system. This invention adopts a staged preheating sequence of shaft seal system → expander body → inlet pipe, matching the expander's startup temperature rise logic, which can avoid damage to components such as the expander rotor, cylinder, and shaft seal caused by alternating hot and cold shocks, ensuring the preheating process is safe. This invention offers enhanced safety and stability. The staged preheating mode enables independent and precise temperature control of each component, improving preheating efficiency. Through an interlocking control structure of temperature sensors and flow regulating valves, it provides real-time feedback on temperature changes in the preheating area, dynamically adjusts the preheating air flow, and precisely controls the temperature rise rate and target preheating temperature, matching the operating temperature requirements given by the expander manufacturer and avoiding insufficient or overheating. Furthermore, by incorporating a regenerative branch, the invention recovers the preheated working fluid and residual heat from the inlet pipe to the compressor inlet, minimizing working fluid loss and heat dissipation during preheating and improving the overall energy utilization efficiency of the compressed air energy storage system. The system structure of this invention is adaptable to large-capacity, high-parameter compressed air energy storage systems with multi-stage compression and expansion, making it widely applicable.

[0043] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the concept and scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the inventive concept should fall within the protection scope of the present invention. All technical contents for which protection is sought in this invention are fully described in the claims.

Claims

1. A compressed air energy storage preheating system, comprising a compression module, an air storage unit, an expansion power generation module connected in sequence, and a heat storage and release module coupled to the compression module and the expansion power generation module; characterized in that: It also includes a preheating control unit, which comprises a preheating gas source branch, a staged preheating component, a regenerative branch, and an interlocking control component. The inlet of the preheating gas source branch is connected to the compressor outlet of the compression module, and the outlet of the preheating gas source branch is connected to each preheating unit of the staged preheating component, used to deliver pressurized hot air generated during compression as a preheating gas source to the staged preheating component. The staged preheating component includes a shaft seal preheating unit, an expander body preheating unit, and an inlet pipe preheating unit arranged sequentially along the preheating process, used to perform staged preheating of the shaft seal system, expander body, and expander inlet pipe of the expansion power generation module, respectively. The inlet of the regenerative branch is connected to the outlet of the inlet pipe preheating unit, and the outlet is connected to the compressor inlet of the compression module, used to recover the preheated working fluid and waste heat. The interlocking control component is signal-connected to the valve components of each preheating unit of the staged preheating component and the preheating gas source branch, used to regulate the on / off state and flow rate of the preheating gas source according to the preheating temperature.

2. The compressed air energy storage preheating system according to claim 1, characterized in that: The compression module includes at least two air compressors connected in series, and the outlet of each air compressor is provided with a cooling heat exchanger connected to the heat storage and release module; the inlet of the preheating gas source branch is connected to the outlet of the first-stage air compressor, and the connection position is located upstream of the cooling heat exchanger corresponding to the first-stage air compressor.

3. The compressed air energy storage preheating system according to claim 1, characterized in that: The expansion power generation module includes at least two stages of air expanders connected in series. Each stage of air expander has a heating heat exchanger connected to the heat storage and release module at its inlet. The shaft seal preheating unit is connected to the shaft seal steam supply station of each stage of air expander. The expander body preheating unit is connected to the internal flow channel of the cylinder of each stage of air expander. The inlet pipe preheating unit is connected to the inlet pipe of each stage of air expander, and the connection position is located downstream of the corresponding heating heat exchanger.

4. The compressed air energy storage preheating system according to claim 1, characterized in that: A gas source shut-off valve is installed on the main pipeline of the preheating gas source branch. Flow regulating valves are installed on the inlet branches of the shaft seal preheating unit, the expander body preheating unit, and the inlet pipeline preheating unit. A recirculation shut-off valve is installed on the reheating branch.

5. The compressed air energy storage preheating system according to claim 4, characterized in that: The interlocking control component includes a temperature sensor and a controller. The temperature sensor is installed at the shaft sealing system, the expander body, and the expander inlet pipe of the expansion power generation module to collect the preheating temperature in real time. The signal input terminal of the controller is connected to the temperature sensor, and the signal output terminal is connected to the gas source shut-off valve, each flow regulating valve, and the return shut-off valve to interlock and control the opening and closing of the corresponding valves based on the comparison result of the collected preheating temperature and the preset threshold.

6. The compressed air energy storage preheating system according to claim 1, characterized in that: The heat storage and release module includes a cold water tank, a hot water tank, a cold water pump, and a hot water pump; wherein, the cold water tank is connected to the cold side inlet of each stage of the cooling heat exchanger of the compression module through the cold water pump, and the cold side outlet of each stage of the cooling heat exchanger is connected to the hot water tank; the hot water tank is connected to the hot side inlet of each stage of the heating heat exchanger of the expansion power generation module through the hot water pump, and the hot side outlet of each stage of the heating heat exchanger is connected to the cold water tank.

7. A method for preheating compressed air energy storage, characterized in that, The preheating system according to any one of claims 1-6 includes the following steps: during the compression energy storage phase when the electrical load is low, the compression module starts up and the expansion power generation module is shut down; the preheating gas source branch is opened, and the pressurized hot air from the compressor outlet of the compression module is used as the preheating gas source, and the staged preheating is completed in the order of first the shaft seal system, then the expander body, and finally the expander inlet pipe; during the preheating process, the preheating temperature is collected in real time through the interlocking control component, and the flow rate of the preheating gas source is dynamically adjusted according to the preheating temperature; after the inlet pipe is preheated, the preheated working fluid flows back to the compressor inlet of the compression module through the reheating branch to complete the recovery of the working fluid and waste heat.

8. The compressed air energy storage preheating method according to claim 7, characterized in that: The timing for initiating the staged preheating is during the last 1 / 3 to 1 / 4 of the compressed energy storage phase.

9. A compressed air energy storage preheating method according to claim 7, characterized in that: During each stage of preheating, when the preheating temperature of the corresponding part reaches the minimum operating temperature requirement of the expander, the air intake branch of the corresponding preheating unit is closed to complete the preheating of that stage.

10. A compressed air energy storage preheating method according to claim 7, characterized in that: When the initial temperature of each part of the expansion power generation module that needs to be preheated is higher than the minimum temperature requirement for commissioning, the preheating gas source branch and the regeneration branch are shut off, and all the air compressed by the compression module is stored in the gas storage unit.

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