A compressed air energy storage thermal power cogeneration system and method using salt cavern geothermal

Abstract

The application discloses a compressed air energy storage combined heat and power system and method using salt cavern geothermal resources, and relates to the field of energy storage, and solves the problems of low energy utilization and low energy storage efficiency in the prior art.The system comprises a salt cavern air storage device and a compressed air energy storage device; the salt cavern air storage device is used for storing high-pressure air and providing geothermal resources; the compressed air energy storage device comprises a power storage structure, a power release structure and a heat release structure; the power storage structure is connected with the salt cavern air storage device and the heat release structure, high-pressure air is obtained by compressing air using electric energy at a low electricity consumption valley, and the high-pressure air is sent to the salt cavern air storage device; the compression process generates residual heat which is sent to the heat release structure; the power release structure is connected with the salt cavern air storage device, high-pressure air is obtained from the salt cavern air storage device at a high electricity consumption peak, and the air pressure energy is converted into electric energy for release; the heat release structure is connected with the salt cavern air storage device and the power storage structure, and geothermal resources of the salt cavern air storage device and residual heat generated in the compression process are used for city heating. The application uses salt cavern geothermal resources to provide city heating, and realizes efficient energy utilization.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy storage, and relates to a compressed air energy storage combined heat and power system and method using salt cavern geothermal energy. BACKGROUND

[0002] The advanced compressed air energy storage system has the advantages of large energy storage scale, high efficiency, long service life, convenient scheduling, no pollution, no dependence on geographical conditions, and low water resource consumption. Due to the mature operation, maintenance and control technology, the product is stable and reliable, and is very suitable for peak shaving and large-scale energy storage of the power grid. The advanced compressed air energy storage system mainly comprises a compressor, a turbine, a cold and heat storage heat exchanger, a gear box, a generator, a motor, a high-pressure air storage tank, valves and pipelines, and a control system, all of which are conventional mechanical equipment.

[0003] Among them, the advanced compressed air energy storage system using salt cavern as a gas storage library can break away from the dependence on fossil fuels such as natural gas and oil, and has great advantages in system scale and initial investment compared with traditional compressed air energy storage systems.

[0004] However, the profit scale of the existing salt cavern type compressed air energy storage system is limited by electricity price policy, and the project recovery period is in a relatively long period of time. In addition, the salt cavern also has abundant natural geothermal resources. The natural salt cavern gas storage library is located underground at about 700-1200 meters, and the stratum temperature at this moment is 40-45℃. The geothermal resources can be used for urban heating, but they have not been effectively utilized.

[0005] In summary, in addition to improving the isentropic efficiency of equipment, developing a multi-combined supply system of salt cavern type compressed air energy storage from the perspective of thermodynamics, fully utilizing the geothermal resources of the salt cavern, and expanding the profit scale of the system, have become one of the difficult problems to be solved in the field of energy storage. SUMMARY

[0006] Therefore, the present application provides a compressed air energy storage combined heat and power system and method using salt cavern geothermal energy, which can store energy using compressed air during peak and off-peak periods of the power grid. Not only high-pressure air is stored in the salt cavity, but also the natural geothermal resources possessed by the salt cavern are fully utilized for urban heating. The system operation efficiency is improved, energy is efficiently utilized, and the economy of the energy storage system and the salt cavern gas storage library is improved, thereby solving the problems in the background technology.

[0007] To achieve the above purpose, the present application provides the following technical scheme:

[0008] In a first aspect, the present application provides a compressed air energy storage combined heat and power system using salt cavern geothermal energy, comprising:

[0009] a salt cavern gas storage device and a compressed air energy storage device;

[0010] Salt cavern gas storage device for storing high-pressure air and providing geothermal resources;

[0011] Compressed air energy storage device, comprising: electricity storage structure, electricity release structure and heat release structure;

[0012] The electricity storage structure is connected with the salt cavern gas storage device and the heat release structure, and is used for compressing air to obtain high-pressure air and delivering the high-pressure air to the salt cavern gas storage device by using electric energy in a low electricity consumption period, and delivering residual heat generated in the compression process to the heat release structure;

[0013] The electricity release structure is connected with the salt cavern gas storage device, and is used for obtaining high-pressure air from the salt cavern gas storage device and converting air pressure energy into electric energy for release in a high electricity consumption period;

[0014] The heat release structure is connected with the salt cavern gas storage device and the electricity storage structure, and obtains geothermal resources of the salt cavern gas storage device and residual heat generated in the compression process to provide city heating.

[0015] Optionally, the electricity storage structure comprises: an electric motor, a plurality of compressors, a plurality of inter-compressor heat exchangers and an energy saver, each compressor is provided with an air inlet and an air outlet, the air inlet of the lowest-level compressor is connected with the electric motor and air respectively, and the air outlet of the highest-level compressor is connected with the salt cavern gas storage device; each heat exchanger is provided with an air inlet, an air outlet, a cold water inlet and a hot water outlet, wherein the air inlet of the heat exchanger is connected with the air outlet of the same-level compressor, the air outlet of the heat exchanger is connected with the air inlet of the next-level compressor, at least one cold water inlet of the heat exchanger is connected with an externally- connected cold water tank, and at least one hot water outlet of the heat exchanger is connected with an externally- connected hot water tank and the energy saver respectively.

[0016] Optionally, the electricity release structure comprises: a plurality of expanders, a plurality of inter-expander reheaters and a generator, each expander is provided with an air inlet and an air outlet, the air inlet of the lowest-level expander is connected with the reheater, and the air outlet of the highest-level expander is connected with the generator; each reheater is provided with an air inlet, an air outlet, a hot water inlet and a cold water outlet, wherein the air inlet of the reheater is connected with the salt cavern gas storage device, the air outlet of the reheater is connected with the air inlet of the same-level expander, at least one hot water inlet of the reheater is connected with a hot water tank, and at least one cold water outlet of the reheater is connected with a water purification device.

[0017] Optionally, the heat-releasing structure comprises: a booster, a heat exchanger, an evaporator, an organic working medium compressor, a condenser and an expansion valve; one end of the heat exchanger is connected with the salt cavern gas storage device for obtaining geothermal resources, and the other end is connected with the booster for boosting the high-pressure air and then delivering the high-pressure air to the salt cavern gas storage device; the heat exchanger is further connected with the energy saver and the evaporator through pipelines in sequence to form a circulating water circuit, for absorbing heat of the geothermal resources, boosting and heating the heat through the organic working medium compressor to obtain high-temperature and high-pressure heat, releasing the high-temperature heat through the condenser to provide heat for the urban heating pipe network, and releasing the pressure through the expansion valve.

[0018] Optionally, the salt cavern gas storage device comprises at least two wells, which are respectively arranged in the top layer of the salt cavity and the brine layer.

[0019] Optionally, a first control valve is arranged between the air outlet of the highest-stage compressor in the electricity storage structure and the well mouth arranged in the brine layer in the salt cavern gas storage device, for controlling the action of the electricity storage structure; a second control valve is arranged between the air inlet of the reheater in the electricity release structure and the well mouth arranged in the top layer of the salt cavity in the salt cavern gas storage device, for controlling the action of the electricity release structure; the first control valve and the second control valve are used for jointly controlling the action of the heat-releasing structure.

[0020] In the second aspect, the embodiments of the present application provide a compressed air energy storage and heat and power cogeneration method using salt cavern geothermal energy, which stores and releases electricity and releases heat based on the system provided in the first aspect, and comprises the following steps:

[0021] In the electricity storage process, high-pressure air is obtained by compressing air using electric energy at a low electricity consumption valley and is delivered to the salt cavern gas storage device, and the remaining heat generated in the compression process is delivered to the heat-releasing structure.

[0022] In the electricity release process, high-pressure air is obtained from the salt cavern gas storage device at a high electricity consumption peak, and the air pressure energy is converted into electric energy for release.

[0023] In the heat release process, the geothermal resources of the salt cavern gas storage device and the remaining heat generated in the compression process are used for urban heating.

[0024] Optionally, the heat generated in the air compression process is used as follows: part of the compression heat of the multi-stage compressor is recovered through the heat exchanger and stored in the heat storage medium, and after the heat is recovered, the heat storage medium is stored in the hot water tank; the remaining part of the compression heat is recovered through the energy saver and is used for heating the organic working medium to provide heat energy for the urban heating pipe network.

[0025] Optionally, the heat generated in the process of converting the air pressure energy into electric energy for release is used as follows: the heat from the heat storage medium in the hot water tank is introduced into the reheater of each stage of the expander, for heating the high-pressure air of each stage of the expander, and the heat-released heat storage medium is stored in the cold water tank.

[0026] Optionally, the geothermal resource utilization process comprises: opening the first control valve and the second control valve, high-pressure air in the well arranged at the top layer of the salt cavity passes through the heat exchanger to transfer heat to the circulating water circuit, the high-pressure air is pressurized by the booster, the high-pressure air in the well arranged at the brine layer enters the high-pressure air storage cavity of the salt cavern gas storage device, heat exchange between the brine and the boundary of the storage cavity is realized, and heat is absorbed and stored; the heat circulating water in the circulating water circuit heats the normal-pressure organic working medium through the evaporator, the high-temperature and high-pressure heat is obtained by pressurizing and heating through the working medium compressor, the high-temperature heat is released through the condenser to provide heat for the urban heating pipe network, and the pressure of the organic working medium is released to normal pressure through the expansion valve; the process of heat absorption, pressure increase, energy release and pressure release of the organic working medium is repeated through the circulating water circuit.

[0027] The technical scheme has the following advantages:

[0028] The compressed air energy storage combined heat and power system and method using salt cavern geothermal energy provided by the application, the system comprises: a salt cavern gas storage device and a compressed air energy storage device; the salt cavern gas storage device is used for storing high-pressure air and providing geothermal resources; the compressed air energy storage device comprises: a power storage structure, a power release structure and a heat release structure; the power storage structure is connected with the salt cavern gas storage device and the heat release structure, and is used for compressing air to obtain high-pressure air by using electric energy at a low power consumption valley and delivering the high-pressure air to the salt cavern gas storage device, and delivering residual heat generated in the compression process to the heat release structure; the power release structure is connected with the salt cavern gas storage device, and is used for obtaining high-pressure air from the salt cavern gas storage device at a high power consumption peak, converting air pressure energy into electric energy and releasing the electric energy; the heat release structure is connected with the salt cavern gas storage device and the power storage structure, and is used for obtaining geothermal resources of the salt cavern gas storage device and residual heat generated in the compression process to provide heat for urban heating. The application not only stores high-pressure air in the salt cavity to realize power peak regulation, but also fully utilizes geothermal resources of the salt cavity for urban heating, improves the system operation efficiency, realizes efficient utilization of energy, and is beneficial to the economy of the energy storage system and the salt cavern gas storage. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical scheme in the specific embodiments or prior art, the drawings needed in the following specific embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can be obtained by those skilled in the art without creating labor.

[0030] Figure 1 The structure schematic diagram of the compressed air energy storage combined heat and power system using salt cavern geothermal energy provided in the embodiment of the application;

[0031] Figure 2A schematic diagram of a specific structure of a compressed air energy storage combined heat and power system utilizing salt cavern geothermal energy provided in an embodiment of the present invention;

[0032] Figure 3 A schematic diagram of a compressed air energy storage combined heat and power method utilizing salt cavern geothermal energy provided in this embodiment of the invention. Detailed Implementation

[0033] To enable those skilled in the art to better understand the present invention, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them, and are not intended to limit the scope of the present invention. Furthermore, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion regarding the concepts disclosed in the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0034] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0035] Example 1

[0036] This invention provides a compressed air energy storage combined heat and power system utilizing salt cavern geothermal energy, such as... Figure 1 As shown, it includes: a salt cavern gas storage device and a compressed air energy storage device; wherein, the salt cavern gas storage device is used to store high-pressure air and provide geothermal resources; the compressed air energy storage device includes: an electric energy storage structure, an electric energy release structure, and a heat release structure; the electric energy storage structure, connected to the salt cavern gas storage device and the heat release structure, is used to compress air using electrical energy during off-peak hours to obtain high-pressure air and transport it to the salt cavern gas storage device, and the residual heat generated during the compression process is transferred to the heat release structure; the electric energy release structure, connected to the salt cavern gas storage device, is used to obtain high-pressure air from the salt cavern gas storage device during peak hours and convert its air pressure energy into electrical energy for release; the heat release structure, connected to the salt cavern gas storage device and the electric energy storage structure, obtains geothermal resources from the salt cavern gas storage device and residual heat generated during the compression process for urban heating.

[0037] This embodiment provides a compressed air energy storage combined heat and power system utilizing salt cavern geothermal energy, such as... Figure 2As shown, the electricity storage structure comprises: an electric motor, a multi-stage compressor, a plurality of inter-compressor heat exchangers, and an energy saver, each stage of the compressor is provided with an air inlet and an air outlet, the air inlet of the lowest stage of the compressor is connected with the electric motor and air respectively, and the air outlet of the highest stage of the compressor is connected with the salt cavern gas storage device; each heat exchanger is provided with an air inlet, an air outlet, a cold water inlet and a hot water outlet, wherein the air inlet of the heat exchanger is connected with the air outlet of the same stage of the compressor, the air outlet of the heat exchanger is connected with the air inlet of the next stage of the compressor, at least one cold water inlet of the heat exchanger is connected with an external cold water tank, and at least one hot water outlet of the heat exchanger is connected with an external hot water tank and the energy saver respectively.

[0038] In a specific embodiment, as shown in the figure, Figure 2 The multi-stage compressor comprises one to eight stages of compressors, and the stages of compressors are connected in series, wherein the first stage is the lowest stage, the level is sequentially increased, the highest stage is the eighth stage, which is only used as an example and is not limited thereto, and adaptive modification can be made according to the actual application scene. The air inlet of the first stage of the compressor is connected with the electric motor, the electric motor is connected with the power grid of the wind power generation through the power transmission line, and the transformer is arranged between the electric motor and the power transmission line, so as to drive the multi-stage compressor to work together through the power grid. Specifically, when the low-pressure air is compressed into high-pressure air by the compressor, heat is released, so that the temperature of the heat exchange medium in the heat exchanger is increased; with continuous compression, the high-pressure air meeting the target requirement is delivered to the salt cavern gas storage device through the air outlet of the eighth stage of the compressor.

[0039] In this embodiment, the electricity release structure comprises: a multi-stage expander, a plurality of inter-expander reheaters, and a generator, each stage of the expander is provided with an air inlet and an air outlet, the air inlet of the lowest stage of the expander is connected with the reheater, and the air outlet of the highest stage of the expander is connected with the generator; each reheater is provided with an air inlet, an air outlet, a hot water inlet and a cold water outlet, wherein the air inlet of the reheater is connected with the salt cavern gas storage device, the air outlet of the reheater is connected with the air inlet of the same stage of the expander, at least one hot water inlet of the reheater is connected with the hot water tank, and at least one cold water outlet of the reheater is connected with the purified water equipment.

[0040] In a specific embodiment, as shown in the figure, Figure 2As shown, the multi-stage expander includes a first-stage to fourth-stage turbine expander, and each stage turbine expander is connected in series, wherein the first stage is the lowest stage, the level is sequentially increased, and the highest stage is the fourth stage, which is only used as an example and is not limited thereto, and adaptive modification is made according to the actual application scene. Specifically, the first-stage turbine expander is connected to the reheater, and when the high-pressure air is expanded into low-pressure air by the turbine expander, heat will be absorbed, and the temperature of the heat exchange medium in the reheater will be reduced. The fourth-stage turbine expander is connected to the generator to drive the generator to generate electricity. The generator is connected to the power grid through the power transmission line. A transformer is arranged between the generator and the power transmission line to jointly release and utilize the air compression energy. This is only used as an example and is not limited thereto. The fourth-stage turbine expander can also be connected to other power equipment to convert air pressure energy into other forms of energy.

[0041] In this embodiment, the heat releasing structure includes a booster, a heat exchanger, an evaporator, an organic working medium compressor, a condenser and an expansion valve. One end of the heat exchanger is connected to the salt cavern gas storage device for obtaining geothermal resources, and the other end is connected to the booster for pressurizing the high-pressure air and then delivering it to the salt cavern gas storage device. The heat exchanger is also connected to the energy saver and the evaporator in sequence through pipelines to form a circulating water path for absorbing the heat of the geothermal resources, increasing the pressure and heating the heat by the organic working medium compressor to obtain high-temperature and high-pressure heat, releasing the high-temperature heat by the condenser to provide heat to the urban heating pipe network, and releasing the pressure by the expansion valve.

[0042] In this embodiment, the salt cavern gas storage device includes at least two wells, which are respectively arranged in the top layer of the salt cavity and the brine layer. Specifically, as shown in the figure, the well arranged in the top layer of the salt cavity is No. 2 well, and the well arranged in the brine layer is No. 1 well. The double well mouth facilitates the circulation of high-pressure hot air and helps efficient use of energy. Figure 2

[0043] In this embodiment, the outlet of the eighth-stage compressor in the power storage structure and the No. 1 well mouth of the salt cavern gas storage device are provided with a first control valve for controlling the operation of the power storage structure. The inlet of the reheater in the power release structure and the No. 2 well mouth of the salt cavern gas storage device are provided with a second control valve for controlling the operation of the power release structure. The first control valve and the second control valve are used to jointly control the operation of the heat releasing structure.

[0044] The present application provides a compressed air energy storage thermal power cogeneration system using salt cavern geothermal energy, which can store energy using compressed air during peak and valley periods of the power grid or during renewable energy grid connection. Not only does it store high-pressure air using a salt cavity, but it also uses the geothermal energy contained in the underground salt cavern to achieve urban heating, increasing the operating efficiency of the salt cavern energy storage system and benefiting the economy of the energy storage system and the salt cavern gas storage.

[0045] Embodiment 2

[0046] ​The embodiment of the present application provides a compressed air energy storage combined heat and power method using salt cavern geothermal energy, as shown in the figure, the method is based on the system provided in the embodiment 1 to store electricity, release electricity and release heat, and comprises a power storage process, a power release process and a heat release process. Figure 3

[0047] In the embodiment, in the power storage process, high-pressure air is obtained by compressing air by using electric energy at a power valley, and the high-pressure air is transported to a salt cavern gas storage device, and the remaining heat generated in the compression process is transported to a heat release structure.

[0048] In a specific embodiment, when the power grid is in a valley or intermittent power generated by renewable energy cannot be put on the grid, the excess power will drive the motor to drive the eight-stage compressor to compress the air to high pressure, open the first control valve, so that the high-pressure air is transported to the salt cavern gas storage device through the No. 1 well mouth, the conversion of electric energy to air pressure energy is completed, and the storage of electric energy is realized. The heat generated in the air compression process is utilized, including: part of the compression heat of the eight-stage compressor is recovered through the heat exchanger and stored in the heat storage medium, and after the heat is recovered, the heat storage medium is stored in the hot water tank; the remaining part of the compression heat is recovered through the economizer and is used for heating the organic working medium to provide heat energy for the city heating pipe network.

[0049] In the embodiment, in the power release process, high-pressure air is obtained from the salt cavern gas storage device at a power peak, and the air pressure energy is converted into electric energy for release.

[0050] In a specific embodiment, at a power peak, the first control valve is closed, and the second control valve is opened, the compressed air is released from the salt cavern gas storage device through the No. 2 well, and the air is expanded to do work through the reheater and the four-stage turbine expander, and the conversion of air pressure energy to electric energy is completed. The heat utilization condition in the process of converting air pressure energy into electric energy for release includes: the heat in the heat storage medium from the hot water tank is introduced into the reheater of each stage of the expander, and is used for heating the high-pressure air of each stage of the expander, and the heat storage medium after releasing heat is stored in the cold water tank.

[0051] In the embodiment, in the heat release process, the geothermal resources of the salt cavern gas storage device and the remaining heat generated in the compression process are used for city heating.

[0052] ​In a specific embodiment, the geothermal resource utilization process comprises: opening the first control valve and the second control valve, high-pressure air in the No. 2 well placed in the top layer of the salt cavity passes through the heat exchanger to transfer heat to the circulating water circuit, and then the high-pressure air is pressurized by the booster, the high-pressure air in the No. 1 well placed in the brine layer enters the high-pressure air storage cavity of the salt cave gas storage device, realizes the heat exchange between the brine and the storage cavity boundary, and is used for absorbing and storing heat; the heat circulating water in the circulating water circuit heats the normal-pressure organic working medium through the evaporator, the high-temperature and high-pressure heat is obtained by the organic working medium compressor, the high-temperature heat is released through the condenser to provide heat for the urban heating pipe network, and the organic working medium pressure is released to normal pressure through the expansion valve; the process of heat absorption, pressure increase, energy release and pressure release of the organic working medium is repeated through the circulating water circuit, so that the cyclic utilization of geothermal resources is realized.

[0053] The application provides a compressed air energy storage heat and power cogeneration method using salt cave geothermal energy, which can realize continuous operation of power storage and heating units for 24 hours, and is beneficial to the economy of the energy storage system; in the energy storage process, part of the compression heat is recycled through the energy-saving device for urban heating, improving the energy utilization rate; in the heat release process, the natural geothermal resources of the salt cave are fully utilized for urban heating, improving the system operation efficiency, realizing efficient utilization of energy, and being beneficial to the economy of the energy storage system and the salt cave gas storage.

[0054] Obviously, the above embodiments are only examples for clearly illustrating, and are not intended to limit the embodiments. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, all the embodiments are not required to be exhausted, and the obvious changes or variations derived therefrom are still within the protection scope of the application.

Claims

1. A compressed air energy storage combined heat and power system utilizing salt cavern geothermal energy, characterized in that, The application relates to a salt cavern gas storage device and a compressed air energy storage device. The salt cavern gas storage device is used for storing high-pressure air and providing geothermal resources. The compressed air energy storage device comprises a power storage structure, a power release structure and a heat release structure. The power storage structure is connected with the salt cavern gas storage device and the heat release structure, and is used for storing high-pressure air by using electric energy during an off-peak period and delivering the high-pressure air to the salt cavern gas storage device, and delivering residual heat generated in the compression process to the heat release structure. The power release structure is connected with the salt cavern gas storage device, and is used for obtaining high-pressure air from the salt cavern gas storage device during a peak period, and converting air pressure energy into electric energy for release. The heat release structure is connected with the salt cavern gas storage device and the power storage structure, and is used for obtaining geothermal resources of the salt cavern gas storage device and residual heat generated in the compression process to provide city heating. The power storage structure comprises a motor, a multi-stage compressor, a plurality of inter-compressor heat exchangers and an energy saver. The heat release structure comprises a booster, a heat exchanger, an evaporator, an organic working medium compressor, a condenser and an expansion valve; one end of the heat exchanger is connected with the salt cavern gas storage device to obtain geothermal resources, and the other end of the heat exchanger is connected with the booster to deliver high-pressure air to the salt cavern gas storage device after the high-pressure air is pressurized; the heat exchanger is further connected with the energy saver and the evaporator through pipelines to form a circulating water circuit, is used for absorbing heat of the geothermal resources, and is used for obtaining high-temperature and high-pressure heat by pressurizing and heating the heat through the organic working medium compressor, releasing the high-temperature heat through the condenser to provide heat for a city heating pipe network, and releasing pressure through the expansion valve. The power storage structure is provided with an air inlet and an air outlet on each stage of the compressor, the air inlets of the lowest stage of the compressor are connected with the motor and air respectively, and the air outlet of the highest stage of the compressor is connected with the salt cavern gas storage device; each heat exchanger is provided with an air inlet, an air outlet, a cold water inlet and a hot water outlet, wherein the air inlet of the heat exchanger is connected with the air outlet of the same stage of the compressor, the air outlet of the heat exchanger is connected with the air inlet of the next stage of the compressor, at least one cold water inlet of the heat exchanger is connected with an external cold water tank, and at least one hot water outlet of the heat exchanger is connected with an external hot water tank and the energy saver respectively.

2. The compressed air energy storage thermal power cogeneration system utilizing salt cavern geothermal according to claim 1, characterized in that, The power release structure comprises a multi-stage expander, a plurality of inter-expander reheaters and a generator, the air inlets and air outlets of each stage of the expander are provided, the air inlet of the lowest stage of the expander is connected with the reheater, the air outlet of the highest stage of the expander is connected with the generator, each reheater is provided with an air inlet, an air outlet, a hot water inlet and a cold water outlet, wherein the air inlet of the reheater is connected with the salt cavern gas storage device, the air outlet of the reheater is connected with the air inlet of the same stage of the expander, at least one hot water inlet of the reheater is connected with a hot water tank, and at least one cold water outlet of the reheater is connected with a water purification device.

3. The compressed air energy storage thermal power cogeneration system utilizing salt cavern geothermal according to claim 1, characterized in that, The salt cavern gas storage device comprises at least two wells arranged in a salt cavity top layer and a brine layer respectively.

4. The compressed air energy storage thermal power cogeneration system utilizing salt cavern geothermal according to claim 1, characterized in that, ​ 5. The compressed air energy storage thermal power cogeneration system utilizing salt cavern geothermal according to any one of claims 2-4, characterized in that, The outlet of the highest level compressor in the electricity storage structure is provided with a first control valve between the well mouth placed in the brine layer of the salt cavern gas storage device, for controlling the action of the electricity storage structure; the inlet of the reheater in the electricity release structure is provided with a second control valve between the well mouth placed in the top layer of the salt cavity of the salt cavern gas storage device, for controlling the action of the electricity release structure; the first control valve and the second control valve are used for jointly controlling the action of the heat release structure.

6. A compressed air energy storage thermal power cogeneration method using salt cavern geothermal, characterized in that, The system based on any one of claims 1-5 is used for electricity storage, electricity release and heat release, comprising: In the electricity storage process, high-pressure air is obtained by compressing air using electric energy at the electricity low valley and is transported to the salt cavern gas storage device, and the residual heat generated in the compression process is transported to the heat release structure; In the electricity release process, high-pressure air is obtained from the salt cavern gas storage device at the electricity peak, and the air pressure energy is converted into electric energy for release; In the heat release process, the geothermal resources of the salt cavern gas storage device and the residual heat generated in the compression process are used for city heating.

7. The compressed air energy storage thermal power generation method using salt cavern geothermal according to claim 6, characterized by, The heat generated in the air compression process is utilized, including: part of the compression heat of the multi-stage compressor is recovered by the heat exchanger and stored in the heat storage medium, and after the heat is recovered, the heat storage medium is stored in the hot water tank; the remaining part of the compression heat is recovered by the energy saver and is used for heating the organic working medium to provide heat energy for the city heating pipe network.

8. The compressed air energy storage thermal power generation method using salt cavern geothermal according to claim 7, characterized by, In the process of converting air pressure energy into electric energy for release, the heat from the heat storage medium in the hot water tank is introduced into the reheater of each stage of the expander, for heating the high-pressure air of each stage of the expander, and the heat release heat storage medium is stored in the cold water tank.

9. The compressed air energy storage thermal power generation method using salt cavern geothermal according to claim 6, characterized by, The geothermal resource utilization process includes: opening the first control valve and the second control valve, the high-pressure air in the well placed in the top layer of the salt cavity passes through the heat exchanger to transfer heat to the circulating water path, and then passes through the booster to pressurize the high-pressure air, and the high-pressure air in the well placed in the brine layer enters the high-pressure air storage cavity of the salt cavern gas storage device, to realize brine and storage cavity boundary heat exchange for absorbing and storing heat; the hot circulating water in the circulating water path heats the organic working medium at normal pressure through the evaporator, and the organic working medium is pressurized and heated by the organic working medium compressor to obtain high-temperature and high-pressure heat, and the high-temperature heat is released through the condenser to provide heat for the city heating pipe network, and the organic working medium is released to normal pressure through the expansion valve; the process of heat absorption, pressure increase, energy release and pressure release of the organic working medium is repeated through the circulating water path.

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