A 300MW-class compressed air energy storage system

Abstract

A 300MW-class compressed air energy storage system, belonging to the field of compressed air energy storage technology, aims to solve the problem of multiple failure points in compressed air energy storage systems. It includes an axial-flow primary compressor, a centrifugal secondary compressor, a first clutch, an integrated electric generator, a second clutch, and an air turbine, all connected coaxially in sequence. During energy storage, the second clutch disengages, and the axial-flow primary compressor is sequentially connected to the centrifugal secondary compressor, the centrifugal tertiary compressor, and the air storage tank. The integrated electric generator drives the axial-flow primary compressor and the centrifugal secondary compressor to supply compressed air to the air storage tank. During energy release, the first clutch disengages, and the air storage tank is connected to the air turbine. The air turbine draws compressed air from the air storage tank to perform work, driving the integrated electric generator to generate electricity. This invention proposes a single-row coaxial integration method for rotating equipment in a compressed air energy storage system, reducing equipment failure points and improving operation and maintenance efficiency.

Description

Technical Field

[0001] This invention belongs to the field of compressed air energy storage technology, and particularly relates to a 300MW-class compressed air energy storage system. Background Technology

[0002] Compressed air energy storage refers to an energy storage method that uses electrical energy to compress air during periods of low grid load and releases the compressed air to drive a steam turbine to generate electricity during periods of high grid load. It has advantages such as large energy storage capacity, long energy storage period, and low investment.

[0003] The basic working principle of compressed air energy storage system is derived from gas turbine system. The working process is divided into two parts: energy storage and energy release. In the storage process, the electric motor drives the compressor to compress and heat the air, forming high-temperature and high-pressure air that is stored in salt caverns or gas tanks. In the energy release process, the high-temperature and high-pressure air drives the air turbine to rotate, generating electricity to the outside world through the generator.

[0004] However, as the power level of energy storage systems increases, the air flow and compressor pressure ratio increase significantly, and the number of electric motors and compressors used for compression also increases accordingly. For example, the compression section of a 300MW-class compressed air energy storage system is a dual-row eight-section type, with a total of 8 compressors and 8 electric motors. This will inevitably lead to an increase in equipment costs, equipment failure points, site space, and operation and maintenance management difficulties, which is not conducive to the efficient, reliable, and stable operation of compressed air energy storage systems. Summary of the Invention

[0005] The purpose of this invention is to provide a 300MW-class compressed air energy storage system to address the problems of high equipment cost, numerous potential failure points, large site requirements, and complex operation and maintenance management associated with 300MW compressed air energy storage systems. The technical solution adopted by this invention is as follows:

[0006] A 300MW-class compressed air energy storage system includes an air storage tank and a rotating equipment. The rotating equipment consists of an axial-flow primary compressor, a centrifugal secondary compressor, a centrifugal tertiary compressor, a first clutch, an integrated electric generator, a second clutch, and an air turbine. The air turbine is a two-stage expansion turbine. The rotors of the centrifugal secondary compressor, the axial-flow primary compressor, the first clutch, the integrated electric generator, the second clutch, and the air turbine are coaxially connected in sequence. The rotating equipment has an integrated modular design, and the rotor of the centrifugal tertiary compressor is arranged separately.

[0007] One end of the gas storage tank, one end of the first-stage cooler, and one end of the first gas-water heat exchanger are connected by a first three-way valve. The compressed air outlet of the axial-flow first-stage compressor, one end of the first oil-gas heat exchanger, and the first-stage expansion inlet of the air turbine are connected by a second three-way valve. The other end of the first gas-water heat exchanger is connected to the other end of the first oil-gas heat exchanger. The other end of the first-stage cooler is connected to the compressed air inlet of the centrifugal second-stage compressor. The first-stage expansion outlet of the air turbine, one end of the second gas-water heat exchanger, and one end of the second-stage cooler are connected by a fourth three-way valve. The compressed air outlet of the centrifugal second-stage compressor, the second-stage expansion inlet of the air turbine, and one end of the second oil-gas heat exchanger are connected by a third three-way valve. The other end of the second gas-water heat exchanger and the other end of the second oil-gas heat exchanger are connected. The other end of the second-stage cooler is connected to the compressed air inlet of the centrifugal third-stage compressor. The compressed air outlet of the centrifugal third-stage compressor is connected sequentially to the other end of the third-stage cooler and the gas storage tank.

[0008] During the energy release process, the first clutch is disengaged, and the gas storage tank is connected to the first expansion inlet of the air turbine in sequence through the first gas-water heat exchanger and the first oil-gas heat exchanger. The first expansion outlet of the air turbine is connected to the second expansion inlet of the air turbine in sequence through the second gas-water heat exchanger and the second oil-gas heat exchanger.

[0009] During the energy storage process, the second clutch is disengaged, and the axial flow primary compressor is connected in sequence through the first oil-gas heat exchanger, the first gas-water heat exchanger, the primary cooler, the centrifugal secondary compressor, the second oil-gas heat exchanger, the second gas-water heat exchanger, the secondary cooler, the centrifugal tertiary compressor, the tertiary cooler, and the other end of the gas storage tank.

[0010] Furthermore, the rotor of the centrifugal three-stage compressor is connected to the output shaft of the variable frequency motor.

[0011] Furthermore, the first clutch is a drum clutch.

[0012] Furthermore, the second clutch is the same model as the first clutch.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] This invention proposes an integrated method for the single-row coaxial rotation of rotating equipment in a 300MW-class compressed air energy storage system, based on the overall integration of rotating equipment in the compressed air energy storage system. This significantly reduces the number of compressors and motors, lowers equipment costs, reduces equipment failure points, and improves operation and maintenance efficiency. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the present invention;

[0016] Figure 2This is a schematic diagram of the integrated connection of the rotating equipment.

[0017] In the diagram, 1. Gas storage tank, 2. First gas-water heat exchanger, 3. First oil-gas heat exchanger, 4. Air turbine, 5. Second gas-water heat exchanger, 6. Second oil-gas heat exchanger, 7. Second clutch, 8. Integrated electric generator, 9. First clutch, 10. Axial flow primary compressor, 11. First three-way valve, 12. Second three-way valve, 13. Primary cooler, 14. Centrifugal secondary compressor, 15. Third three-way valve, 16. Fourth three-way valve, 17. Secondary cooler, 18. Centrifugal tertiary compressor, 19. Variable frequency motor, 20. Tertiary cooler. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0019] The connections mentioned in this invention are divided into fixed connections and detachable connections. Fixed connections, also known as non-detachable connections, include but are not limited to conventional fixed connection methods such as folded connections, riveted connections, adhesive connections, and welded connections. Detachable connections include but are not limited to conventional disassembly methods such as bolted connections, snap-fit ​​connections, pin connections, and hinged connections. When a specific connection method is not explicitly defined, it is assumed that at least one existing connection method can be found to achieve this function, and those skilled in the art can choose according to their needs. For example, a welded connection can be chosen for fixed connections, and a bolted connection can be chosen for detachable connections.

[0020] The present invention will be further described in detail below with reference to the accompanying drawings. The following embodiments are explanations of the present invention, but the present invention is not limited to the following embodiments.

[0021] Example: Figure 1-2 As shown, hollow arrows represent the direction of compressed air flow during energy storage, while solid arrows represent the direction of compressed air flow during energy release.

[0022] A 300MW-class compressed air energy storage system includes an air storage tank 1 and a rotating device. The rotating device consists of an axial-flow primary compressor 10, a centrifugal secondary compressor 14, a centrifugal tertiary compressor 18, a first clutch 9, an integrated electric generator 8, a second clutch 7, and an air turbine 4. The air turbine 4 is a two-stage expansion turbine. The rotors of the centrifugal secondary compressor 14, the axial-flow primary compressor 10, the first clutch 9, the integrated electric generator 8, the second clutch 7, and the air turbine 4 are coaxially connected in sequence. The rotating device has an integrated modular design, and the rotor of the centrifugal tertiary compressor 18 is arranged separately.

[0023] One end of the gas storage tank 1, one end of the first-stage cooler 13, and one end of the first gas-water heat exchanger 2 are connected by a first three-way valve 11. The compressed air outlet of the axial-flow first-stage compressor 10, one end of the first oil-gas heat exchanger 3, and the first-stage expansion inlet of the air turbine 4 are connected by a second three-way valve 12. The compressed air inlet of the axial-flow first-stage compressor 10 is connected to the atmospheric environment. The other end of the first gas-water heat exchanger 2 is connected to the other end of the first oil-gas heat exchanger 3. The other end of the first-stage cooler 13 is connected to the compressed air inlet of the centrifugal second-stage compressor 14. The first-stage expansion outlet of the air turbine 4 and the second gas-water heat exchanger... One end of the device 5 and one end of the secondary cooler 17 are connected through the fourth three-way valve 16. The compressed air outlet of the centrifugal secondary compressor 14, the secondary expansion inlet of the air turbine 4, and one end of the second oil-gas heat exchanger 6 are connected through the third three-way valve 15. The secondary expansion outlet of the air turbine 4 is connected to the atmospheric environment. The other end of the second gas-water heat exchanger 5 is connected to the other end of the second oil-gas heat exchanger 6. The other end of the secondary cooler 17 is connected to the compressed air inlet of the centrifugal tertiary compressor 18. The compressed air outlet of the centrifugal tertiary compressor 18 is connected in sequence to the other end of the tertiary cooler 20 and the air storage tank 1.

[0024] During the energy release process, the first clutch 9 is disengaged, and the gas storage tank 1 is connected to the first expansion inlet of the air turbine 4 through the first gas-water heat exchanger 2 and the first oil-gas heat exchanger 3 in sequence. The first expansion outlet of the air turbine 4 is connected to the second expansion inlet of the air turbine 4 through the second gas-water heat exchanger 5 and the second oil-gas heat exchanger 6 in sequence.

[0025] During the energy storage process, the second clutch 7 is disengaged, and the axial flow primary compressor 10 sequentially passes through the first oil-gas heat exchanger 3, the first gas-water heat exchanger 2, the primary cooler 13, the centrifugal secondary compressor 14, the second oil-gas heat exchanger 6, the second gas-water heat exchanger 5, the secondary cooler 17, the centrifugal tertiary compressor 18, the tertiary cooler 20, and the other end of the gas storage tank 1, which is connected to the first oil-gas heat exchanger, the first gas-water heat exchanger, the second oil-gas heat exchanger, and the second gas-water heat exchanger.

[0026] The rotor of the centrifugal three-stage compressor 18 is connected to the output shaft of the variable frequency motor 19.

[0027] The first clutch 9 is a drum clutch.

[0028] The second clutch 7 has the same model as the first clutch 9.

[0029] The rotating device of this invention consists of an axial-flow primary compressor 10, a centrifugal secondary compressor 14, a centrifugal tertiary compressor 18, a first clutch 9, an integrated electric generator 8, a second clutch 7, and an air turbine 4. The working process is divided into a compression energy storage process and an expansion energy release process. From the perspective of the overall integration of the rotating device of the compressed air energy storage system, this invention proposes a single-row coaxial integration method for the rotating device of a 300MW-level compressed air energy storage system, thereby significantly reducing the number of compressors and motors, reducing equipment costs, reducing equipment failure points, and improving operation and maintenance efficiency.

[0030] The aforementioned compression and energy storage process is achieved by an axial-flow primary compressor 10, a centrifugal secondary compressor 14, a centrifugal tertiary compressor 18, a first clutch 9, and an integrated electric generator 8. The axial-flow compressor has high efficiency, a large pressure ratio, and a large flow rate; therefore, the axial-flow primary compressor 10 is used for the first stage of compression in this invention. The centrifugal compressor has a wide load range and good adjustability; therefore, the centrifugal secondary compressor 14 and the centrifugal tertiary compressor 18 are used for the second and third stages of compression in this invention, respectively. Since the flow rate of the axial-flow primary compressor 10 for the first stage compression is sufficiently large, the centrifugal tertiary compressor 18 used for the third stage compression can be designed in a single-row arrangement.

[0031] The axial-flow primary compressor 10, the centrifugal secondary compressor 14, and the integrated electric generator 8 are coaxially designed through the first clutch 9, with a rotational speed of 3000 rpm.

[0032] The centrifugal three-stage compressor 18 is used to regulate the outlet pressure of the compression energy storage process and is driven by a separate high-speed variable frequency motor 19, thereby maintaining the flexibility of the centrifugal three-stage compressor 18 in regulation.

[0033] The first clutch 9 is a high-power torque-transmitting clutch, capable of disengaging and engaging when the two clutch-engaged rotors are rotating relative to each other or stationary. During compression and energy storage, the first clutch 9 is engaged, connecting the rotor of the axial-flow primary compressor 10 to the rotor of the integrated electric generator 8, forming a coaxial design. During expansion and energy release, the first clutch 9 is disengaged, the integrated electric generator 8 is used as a generator, and the axial-flow primary compressor 10 does not operate.

[0034] The aforementioned expansion and energy release process is achieved by the integrated electric generator 8, the second clutch 7, and the air turbine 4. The second clutch 7 is the same high-power torque-transmitting clutch as the first clutch 9. During the expansion and energy release process, the second clutch 7 is engaged, and the integrated electric generator 8 functions as a generator. The rotor of the integrated electric generator 8 is connected to the rotor of the air turbine 4 via the second clutch 7, forming a coaxial design. During the compression and energy storage process, the second clutch 7 is disengaged, and the integrated electric generator 8 functions as a motor; the air turbine 4 does not operate.

[0035] The integrated electric generator 8 has functions such as power generation, driving, and phase regulation. It can act as an electric motor during the compression and energy storage process, converting electrical energy into mechanical energy to drive the rotor of the axial flow primary compressor 10 and the rotor of the centrifugal secondary compressor 14. Furthermore, during the expansion and energy release process, the integrated electric generator 8 can act as a generator, converting the mechanical energy of the air turbine 4 into electrical energy to supply power to the grid. Depending on the needs of the grid, it can also act as a synchronous condenser to increase or decrease reactive power, improve the power factor of the grid, and maintain the grid voltage level.

[0036] The gas storage tank 1 is used to store compressed air. During the energy release process, the air turbine 4 draws compressed air from the gas storage tank 1 to perform external work. The amount of compressed air stored in the gas storage tank 1 is enough for the air turbine 4 to use for about six hours. During the energy storage process, the axial flow first-stage compressor 10, the centrifugal second-stage compressor 14, and the centrifugal third-stage compressor 18 draw air from the atmospheric environment, compress it, and store it in the gas storage tank 1.

[0037] This invention uses air as the working fluid, with the inlet at normal temperature and pressure. During the compression and energy storage process, the integrated electric generator 8 functions as an electric motor, connected to the rotor of the axial-flow primary compressor 10 via a first clutch 9 to drive the compressor. Air entering the axial-flow primary compressor 10 is compressed, gaining pressure and temperature, and then sequentially exchanges heat with the first oil-gas heat exchanger 3, the first gas-water heat exchanger 2, and the primary cooler 13, causing the air temperature to drop to 40°C and the heat exchange medium temperature to rise above 330°C. The air then enters the centrifugal secondary compressor 14 for further pressure and temperature increases. After leaving the centrifugal secondary compressor 14, the air sequentially exchanges heat with the second oil-gas heat exchanger 6, the second gas-water heat exchanger 5, and the secondary cooler 17, causing the air temperature to drop to 40°C and the heat exchange medium temperature to rise above 330°C. Finally, the air enters the centrifugal tertiary compressor 18 for further pressure and temperature increases. After leaving the centrifugal three-stage compressor 18, the air enters the three-stage cooler 20 to be cooled, and finally forms high-pressure low-temperature air which enters the air storage tank 1 for storage.

[0038] In the above-mentioned compression energy storage process, electrical energy is converted into air pressure energy and thermal energy. The air pressure energy is stored in the air storage tank of air storage 1, and the air thermal energy is stored in the heat storage device through the heat exchange medium.

[0039] During the expansion energy storage process, the integrated electric generator 8 functions as a generator, connected to the rotor of the air turbine 4 via the second clutch 7. The air turbine 4 drives the integrated electric generator 8. Air is released from the gas storage tank 1, passes through the first gas-water heat exchanger 2 and the first oil-gas heat exchanger 3, and its temperature rises to 310°C. The air then enters the air turbine 4 to expand and perform work. The air turbine 4 employs a two-stage reheat design. After the air enters the air turbine 4 and performs the first stage of expansion and work, it is reheated to 310°C through the second gas-water heat exchanger 5 and the second oil-gas heat exchanger 6 before entering the air turbine 4 again for the second stage of expansion and work, and then discharged into the atmosphere.

[0040] During the aforementioned expansion and energy release process, air pressure energy and thermal energy are converted into electrical energy, which is then supplied to the power grid via the integrated electric generator 8.

[0041] The above embodiments are merely illustrative examples of the present invention and do not limit its scope of protection. Those skilled in the art can make partial changes to them, as long as they do not exceed the spirit and essence of the present invention, they are all within the scope of protection of the present invention.

Claims

1. A 300MW-class compressed air energy storage system, characterized in that: It includes a gas storage tank (1) and a rotating device. The rotating device consists of an axial flow primary compressor (10), a centrifugal secondary compressor (14), a centrifugal tertiary compressor (18), a first clutch (9), an electric generator (8), a second clutch (7), and an air turbine (4). The air turbine (4) is a two-stage expansion turbine. The rotors of the centrifugal secondary compressor (14), the axial flow primary compressor (10), the first clutch (9), the electric generator (8), the second clutch (7), and the air turbine (4) are connected coaxially in sequence. The rotating device has an integrated modular design, and the rotor of the centrifugal tertiary compressor (18) is arranged separately. One end of the gas storage tank (1), one end of the first-stage cooler (13), and one end of the first gas-water heat exchanger (2) are connected by a first three-way valve (11). The compressed air outlet of the axial-flow first-stage compressor (10), one end of the first oil-gas heat exchanger (3), and the first-stage expansion inlet of the air turbine (4) are connected by a second three-way valve (12). The other end of the first gas-water heat exchanger (2) is connected to the other end of the first oil-gas heat exchanger (3). The other end of the first-stage cooler (13) is connected to the compressed air inlet of the centrifugal second-stage compressor (14). The first-stage expansion outlet of the air turbine (4) and the second gas-water heat exchanger (5) are connected by a first three-way valve (11). One end of the centrifugal secondary compressor (14) and one end of the secondary cooler (17) are connected through the fourth three-way valve (16). The compressed air outlet of the centrifugal secondary compressor (14), the secondary expansion inlet of the air turbine (4), and one end of the second oil-gas heat exchanger (6) are connected through the third three-way valve (15). The other end of the second gas-water heat exchanger (5) and the other end of the second oil-gas heat exchanger (6) are connected. The other end of the secondary cooler (17) is connected to the compressed air inlet of the centrifugal tertiary compressor (18). The compressed air outlet of the centrifugal tertiary compressor (18) is connected in sequence to the other end of the tertiary cooler (20) and the gas storage tank (1). During the energy release process, the first clutch (9) is disengaged, and the gas storage tank (1) is connected to the first expansion inlet of the air turbine (4) in sequence through the first gas-water heat exchanger (2) and the first oil-gas heat exchanger (3). The first expansion outlet of the air turbine (4) is connected to the second expansion inlet of the air turbine (4) in sequence through the second gas-water heat exchanger (5) and the second oil-gas heat exchanger (6). During the energy storage process, the second clutch (7) is disengaged, and the axial flow primary compressor (10) is connected to the other end of the gas storage tank (1) in sequence through the first oil-gas heat exchanger (3), the first gas-water heat exchanger (2), the primary cooler (13), the centrifugal secondary compressor (14), the second oil-gas heat exchanger (6), the second gas-water heat exchanger (5), the secondary cooler (17), the centrifugal tertiary compressor (18), the tertiary cooler (20), and the gas storage tank (1).

2. The 300MW-class compressed air energy storage system according to claim 1, characterized in that: The rotor of the centrifugal three-stage compressor (18) is connected to the output shaft of the variable frequency motor (19).

3. A 300MW-class compressed air energy storage system according to claim 1 or 2, characterized in that: The first clutch (9) is a drum clutch.

4. A 300MW-class compressed air energy storage system according to claim 3, characterized in that: The second clutch (7) is the same model as the first clutch (9).

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