A compressed air energy storage power generation system and method

Abstract

The present invention belongs to the technical field of compressed air energy storage, and particularly relates to a compressed air energy storage power generation system and method. Aiming at the deficiencies of existing compressed air energy storage systems, such as the need to consume a large amount of fuel or low efficiency, the present invention adopts the following technical solutions: A compressed air energy storage power generation system includes: a water pool; an air compressor; a water storage tank; a centrifugal pump; a gas-water separation device; a gas storage tank; a low-pressure side water turbine power generation device; a high-pressure side water turbine power generation device; during energy storage, the air compressor is used to make the water in the water storage tank enter the low-pressure side water turbine power generation device for low-pressure power generation; during power generation, high-pressure power generation is carried out first, and when the pressure in the gas storage tank drops to the third preset value, low-pressure power generation is carried out. The beneficial effects of the present invention are: during energy storage, through the cycle of injecting water to compress air and discharging water, the air pressure in the gas storage tank can be made higher; during energy storage, the discharged water is used for low-pressure power generation, and part of the energy can be recovered.

Description

Technical Field

[0001] The present invention belongs to the technical field of compressed air energy storage, and particularly relates to a compressed air energy storage power generation system and method. Background Art

[0002] With the development of the energy Internet and environmental protection requirements, more and more renewable energy sources are incorporated into the power grid for power generation. These renewable energy sources are characterized by intermittency and large fluctuations. Their large-scale utilization will inevitably cause the problem of peak shaving in the power grid and impact the stability of the power grid load supply and demand. Therefore, energy storage technologies have emerged. Through an energy storage system, electrical energy is converted into other energy forms for storage during the low electricity consumption period or the high power generation period. When the electricity consumption peak or the power generation low period occurs, the stored energy is used to generate electricity and feed it into the grid through power equipment, thereby ensuring a stable supply and demand relationship in the power grid.

[0003] Currently, there are two large-scale energy storage methods: pumped hydro energy storage and compressed air energy storage. Pumped hydro energy storage has a high energy conversion efficiency of up to 75%, but it requires large-capacity upstream and downstream reservoirs with a certain height difference, has high requirements for site selection, and may also damage the natural ecological environment, with relatively large limitations. In contrast, compressed air energy storage does not have these problems of the former and has broad development and application prospects.

[0004] However, in the existing compressed air energy storage system, there are many internal heat exchange links, large irreversible losses, and moreover, a large amount of fuel needs to be consumed during the power generation stage to ensure a high output power and efficiency. Summary of the Invention

[0005] In view of the deficiencies of the existing compressed air energy storage system, such as the need to consume a large amount of fuel or low efficiency, the present invention provides a compressed air energy storage power generation system to achieve improvement in a certain aspect. The present invention also provides a compressed air energy storage power generation method.

[0006] To achieve the above object, the present invention adopts the following technical solutions: A compressed air energy storage power generation system, the compressed air energy storage power generation system comprising:

[0007] A water pool;

[0008] An air compressor;

[0009] A water storage tank;

[0010] A centrifugal pump;

[0011] A gas-liquid separation device;

[0012] A gas storage tank;

[0013] Pipes and valves;

[0014] Low-pressure side hydroelectric power generation equipment;

[0015] High-voltage side hydroelectric power generation equipment;

[0016] During energy storage, the centrifugal pump injects water from the water pool into the upper part of the water storage tank. When the air pressure in the water storage tank reaches the first preset value, the valve is opened to allow the gas-liquid mixture in the water storage tank to enter the gas-water separation device. The separated gas enters the gas storage tank, and the separated water is discharged into the water pool. After the water storage tank is filled with water, an air compressor is used to make the water in the water storage tank enter the low-voltage side hydroelectric power generation equipment for low-voltage power generation. The above operations are repeated until the high-pressure air pressure in the gas storage tank reaches the second preset value and the water storage tank is full of water;

[0017] During power generation, the high-pressure air in the gas storage tank is used to inject the water in the water storage tank into the high-voltage side hydroelectric power generation equipment for high-voltage power generation. When the pressure in the gas storage tank drops to the third preset value, the air in the gas storage tank is used to inject the water in the water storage tank into the low-voltage side hydroelectric power generation equipment for low-voltage power generation.

[0018] The compressed air energy storage power generation system of the present invention, during energy storage, first compresses air with water and then stores the compressed air. During power generation, the compressed air is used to make water flow for power generation, which has the advantages of being green and pollution-free, etc.; during energy storage, through the cycle of injecting water to compress air and discharging water, the air pressure in the gas storage tank can be made higher; during energy storage, the discharged water is used for low-voltage power generation, and some energy can be recovered.

[0019] As an improvement, before energy storage, the air compressor pre-presses the water storage tank, the gas storage tank, and the gas-water separation device, and then energy storage is carried out. Using the air compressor to quickly establish a certain initial pressure for the system at the initial stage of energy storage can save the total time of energy storage to a certain extent.

[0020] As an improvement, both the water storage tank and the gas storage tank are buried underground for isothermal compression; the gas-water separation device is buried underground. The isothermal compression method can not only further compress the air, but also achieve air compression with lower energy consumption. Utilize the soil to exchange heat with the water outlet pipe, the gas storage tank, and even the gas-water separation device, without the need to additionally set up a heat exchange device.

[0021] As an improvement, during energy storage, the air flow rate of the air compressor and the water discharge flow rate of the water storage tank are controlled to achieve constant-pressure water discharge.

[0022] As an improvement, there are multiple centrifugal pumps; there are multiple water storage tanks; there are multiple gas storage tanks.

[0023] As an improvement, valves are provided between the centrifugal pump and the water storage tank; between the water storage tank and the gas-water separation device; between the gas-water separation device and the gas storage tank; between the gas storage tank and the water storage tank; between the air compressor and the water storage tank; between the air compressor and the gas storage tank; between the water storage tank and the high-pressure side water turbine power generation equipment; and between the water storage tank and the low-pressure side water turbine power generation equipment.

[0024] A compressed air energy storage power generation method, the compressed air energy storage power generation method comprising the following steps:

[0025] Step S2: Use a centrifugal pump to inject water from the water pool into the water storage tank from the upper part of the water storage tank. When the air pressure in the water storage tank reaches the first preset value, open the valve to allow the mixed gas-liquid in the water storage tank to enter the gas-water separation device. The separated gas enters the gas storage tank, and the separated water is discharged into the water pool. After the water storage tank is filled with water, use an air compressor to send the water in the water storage tank to the low-pressure side water turbine power generation equipment for low-pressure power generation. Repeat the above operations until the air pressure in the gas storage tank reaches the second preset value and the water storage tank is full of water;

[0026] Step S3: Use the high-pressure air in the gas storage tank to pressurize the water storage tank, and the water in the water storage tank is injected into the high-pressure side water turbine power generation equipment for high-pressure power generation;

[0027] Step S4: When the pressure in the gas storage tank drops to the third preset value, use the remaining air in the gas storage tank to pressurize the water storage tank, and the water in the water storage tank is injected into the low-pressure side water turbine power generation equipment for low-pressure power generation.

[0028] As an improvement of the energy storage power generation method, the compressed air energy storage power generation method further includes:

[0029] Step S1: Use an air compressor to pre-pressurize the water storage tank, the gas-water separation device, and the gas storage tank to raise the pressure in the water storage tank, the gas-water separation device, and the gas storage tank to a certain value.

[0030] As an improvement of the energy storage power generation method, in step S2, during compression, the gas storage tank and the water storage tank exchange heat with the soil.

[0031] As an improvement of the energy storage power generation method, in step S2, during energy storage, the constant pressure drainage is achieved by controlling the air flow rate of the air compressor and the drainage flow rate of the water storage tank.

[0032] The beneficial effects of the compressed air energy storage power generation system of the present invention are as follows: During energy storage, water is first used to compress air, and then the compressed air is stored. During power generation, the compressed air is used to make water flow for power generation, which has the advantages of being green and pollution-free; during energy storage, through the cycle of injecting water to compress air and discharging water, the air pressure in the gas storage tank can be higher; during energy storage, the discharged water is used for low-pressure power generation, and part of the energy can be recovered. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a structural block diagram of the compressed air energy storage power generation system according to Embodiment 1 of the present invention.

[0034] Figure 2 is a structural block diagram of the compressed air energy storage power generation system during pre-pressurization according to Embodiment 1 of the present invention.

[0035] Figure 3 is a structural block diagram of the compressed air energy storage power generation system during energy storage according to Embodiment 1 of the present invention.

[0036] Figure 4 is a structural block diagram of the compressed air energy storage power generation system during low-pressure side power generation in the energy storage process according to Embodiment 1 of the present invention.

[0037] Figure 5 is a structural block diagram of the compressed air energy storage power generation system during high-pressure side power generation according to Embodiment 1 of the present invention.

[0038] Figure 6 is a structural block diagram of the compressed air energy storage power generation system during low-pressure side power generation according to Embodiment 1 of the present invention.

[0039] In the figure, 1, the first centrifugal pump;

[0040] 2, the second centrifugal pump;

[0041] 3, the water storage tank;

[0042] 4, the gas storage tank;

[0043] 5, the gas-water separation device;

[0044] 6, the air compressor;

[0045] 7, the water pool;

[0046] 8, the high-pressure side water turbine power generation equipment;

[0047] 9, the low-pressure side water turbine power generation equipment;

[0048] 10 to 21, valves (the valves filled with black indicate closed); 22 to 31, pipelines. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0049] Combined with the accompanying drawings of the embodiments of the present invention, the technical solutions of the embodiments of the present invention will be explained and described. However, the following embodiments are only the preferred embodiments of the present invention, not all of them. Based on the embodiments in the implementation manner, other embodiments obtained by those skilled in the art without creative efforts all fall within the protection scope of the present invention.

[0050] Referring to Figures 1 to 6 , a compressed air energy storage power generation system of the present invention, the compressed air energy storage power generation system includes:

[0051] A water pool;

[0052] An air compressor;

[0053] A water storage tank;

[0054] A centrifugal pump;

[0055] A gas-liquid separation device;

[0056] A gas storage tank;

[0057] Pipes and valves;

[0058] Low-pressure side water turbine power generation equipment;

[0059] High-pressure side water turbine power generation equipment;

[0060] During energy storage, the centrifugal pump injects the water in the water pool into the water storage tank from the upper part of the water storage tank. When the air pressure in the water storage tank reaches the first preset value, the valve is opened to enable the mixed gas-liquid in the water storage tank to enter the gas-liquid separation device. The separated gas enters the gas storage tank, and the separated water is discharged into the water pool. After the water storage tank is filled with water, the air compressor is used to make the water in the water storage tank enter the low-pressure side water turbine power generation equipment for low-pressure power generation. The above operations are repeated until the high-pressure air pressure in the gas storage tank reaches the second preset value and the water storage tank is full of water;

[0061] During power generation, the high-pressure air in the gas storage tank is used to inject the water in the water storage tank into the high-pressure side water turbine power generation equipment for high-pressure power generation. When the pressure in the gas storage tank drops to the third preset value, the air in the gas storage tank is used to inject the water in the water storage tank into the low-pressure side water turbine power generation equipment for low-pressure power generation.

[0062] The compressed air energy storage power generation system of the present invention, during energy storage, first compresses air with water and then stores the compressed air. During power generation, the compressed air is used to make water flow for power generation, having the advantages of being green and pollution-free, etc.; during energy storage, through the cycle of injecting water to compress air and discharging water, the air pressure in the gas storage tank can be higher; during energy storage, the discharged water is used for low-pressure power generation, and part of the energy can be recovered.

[0063] Embodiment 1

[0064] See Figures 1 to 6 , a compressed air energy storage power generation system according to Embodiment 1 of the present invention, the compressed air energy storage power generation system includes:

[0065] Water pool 7;

[0066] Air compressor 6;

[0067] Water storage tank 3;

[0068] Centrifugal pump;

[0069] Gas-water separation device 5;

[0070] Gas storage tank 4;

[0071] Pipes and valves;

[0072] Low-pressure side water turbine power generation equipment 9;

[0073] High-pressure side water turbine power generation equipment 8;

[0074] During energy storage, the centrifugal pump injects the water in the water pool 7 into the water storage tank 3 from the upper part of the water storage tank 3. When the air pressure in the water storage tank 3 reaches the first preset value, the valve is opened to make the gas-liquid mixture in the water storage tank 3 enter the gas-water separation device 5. The separated gas enters the gas storage tank 4, and the separated water is discharged into the water pool 7. After the water storage tank 3 is filled with water, the air compressor 6 is used to make the water in the water storage tank 3 enter the low-pressure side water turbine power generation equipment 9 for low-pressure power generation. The above operation is repeated until the high-pressure air pressure in the gas storage tank 4 reaches the second preset value and the water storage tank 3 is full of water;

[0075] During power generation, the high-pressure air in the gas storage tank 4 is used to inject the water in the water storage tank 3 into the high-pressure side water turbine power generation equipment 8 for high-pressure power generation. When the pressure in the gas storage tank 4 drops to the third preset value, the air in the gas storage tank 4 is used to inject the water in the water storage tank 3 into the low-pressure side water turbine power generation equipment 9 for low-pressure power generation.

[0076] In this embodiment, before energy storage, the air compressor 6 pre-presses the water storage tank 3, the gas storage tank 4, and the gas-water separation device 5, and then energy storage is carried out.

[0077] In this embodiment, both the water storage tank 3 and the gas storage tank 4 are buried in the ground surface for isothermal compression; the gas-water separation device 5 is buried in the ground surface. The isothermal compression method can not only further compress the air, but also achieve the compression of air with lower energy consumption.

[0078] In this embodiment, during energy storage, the constant-pressure drainage is achieved by controlling the air flow rate of the air compressor 6 and the drainage flow rate of the water storage tank 3.

[0079] In this embodiment, there are two centrifugal pumps, the first centrifugal pump 1 and the second centrifugal pump 2 are connected in parallel.

[0080] In other embodiments, there can be multiple water storage tanks 3; there can be multiple gas storage tanks 4.

[0081] In this embodiment, valves are provided between the centrifugal pump and the water storage tank 3; valves are provided between the water storage tank 3 and the gas-water separation device 5; valves are provided between the gas-water separation device 5 and the gas storage tank 4; valves are provided between the gas storage tank 4 and the water storage tank 3; valves are provided between the air compressor 6 and the water storage tank 3; valves are provided between the air compressor 6 and the gas storage tank 4; valves are provided between the water storage tank 3 and the high-pressure side water turbine power generation equipment 8; valves are provided between the water storage tank 3 and the low-pressure side water turbine power generation equipment 9.

[0082] In this embodiment, the specific process of the compressed air energy storage power generation system during pre-pressurization is as follows: At the initial stage of system startup, valves 16, 17, 18, 20 are opened, and valves 10, 11, 12, 13, 14, 15, 19, 21 are closed. The air compressor 6 is started, and the pressures in the water storage tank 3, the gas storage tank 4, and the gas-water separation device 5 are pre-pressurized through pipelines 27 (including 27-1 and 27-2), 28, and 29, so that the pressures in the water storage tank 3, the gas storage tank 4, and the gas-water separation device 5 are increased to a certain value.

[0083] In this embodiment, the specific process of the system energy storage and low-pressure side power generation operation mode is as follows: During energy storage, the air compressor 6 is shut down, valves 16 and 17 are closed, the centrifugal pumps 1 and 2 are started, valves 10, 11, and 12 are opened. The centrifugal pumps 1 and 2 transport the water in the water pool 7 through the pipeline 22 and inject water into the water storage tank 3. As the water level in the water storage tank 3 rises, the air is gradually compressed under the principle of isothermal compression, passes through the pipeline 28 to the gas-water separation device 5, and the separated air is injected into the gas storage tank 4 through the pipeline 29.

[0084] During low-pressure side power generation, after the water storage tank 3 is filled with water, the centrifugal pumps 1 and 2 are shut down, valves 10, 11, 12, and 18 are closed, the air compressor 6 is started, valves 14 and 16 are opened. Through the pipeline 27 (27-1), the water in the water storage tank 3 enters the low-pressure side water turbine generator equipment 9 through the pipeline 24 to convert the potential energy of the water into electric energy again. The water that has done work is discharged into the water pool 7 through the pipeline 25. After the water in the water storage tank 3 is drained, the air compressor 6 is shut down, valve 16 is closed, and valves 10, 11, 12, and 18 are opened.

[0085] Repeat the above energy storage and low-pressure power generation operations until the gas storage tank 4 is filled with compressed high-pressure air.

[0086] In this embodiment, the specific processes of power generation on the high-voltage and low-voltage sides of the system are as follows: When the system generates power on the high-voltage side, it is confirmed that the water in the water storage tank 3 is full and the air in the air storage tank 4 is full. Valves 10, 11, 12, 14, 16, 18, and 20 are closed, and valves 17 and 13 are opened. The high-pressure air in the air storage tank 4 is used to pressurize the water in the water storage tank 3 through pipelines 27-1 and 27-2. The water is injected into the high-voltage side water turbine power generation equipment 8 through pipeline 23, converting the potential energy of the water into mechanical energy and then into electrical energy. When the system generates power on the low-voltage side, after the pressure in the water storage tank 3 drops to a certain value, valve 14 is opened and valve 13 is closed. The water is injected into the low-voltage side water turbine power generation equipment 9 through pipeline 24, further converting the potential energy of the water into mechanical energy and then into electrical energy. The water that has done work in the water turbine power generation equipment is discharged into the water pool 7 through 25 and 30.

[0087] The beneficial effects of the compressed air energy storage power generation system in the first embodiment of the present invention are as follows: During energy storage, water is first used to compress air, and then the compressed air is stored. During power generation, compressed air is used to make water flow for power generation, which has the advantages of being green and pollution-free, etc.; during energy storage, through the cycle of injecting water to compress air and discharging water, the air pressure in the air storage tank 4 can be higher; during energy storage, the discharged water is used for low-voltage power generation, and part of the energy can be recovered.

[0088] As described above, the above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes but is not limited to the content described in the above specific implementation manner. Any modification that does not deviate from the functional and structural principles of the present invention will be included in the scope of the claims.

Claims

1. A compressed air energy storage power generation system, characterized in that: The compressed air energy storage power generation system includes: A water pool; An air compressor; A water storage tank; A centrifugal pump; A gas-water separation device; A gas storage tank; Pipes and valves; Low-pressure side hydroelectric power generation equipment; High-pressure side hydroelectric power generation equipment; During energy storage, the centrifugal pump injects water from the water pool into the water storage tank from the upper part of the water storage tank. When the air pressure in the water storage tank reaches the first preset value, the valve is opened to allow the mixed gas-liquid in the water storage tank to enter the gas-water separation device. The separated gas enters the gas storage tank, and the separated water is discharged into the water pool. After the water storage tank is filled with water, the air compressor is used to make the water in the water storage tank enter the low-pressure side hydroelectric power generation equipment for low-pressure power generation. The above operations are repeated until the high-pressure air pressure in the gas storage tank reaches the second preset value and the water storage tank is full of water; During power generation, the high-pressure air in the gas storage tank is used to inject the water in the water storage tank into the high-pressure side hydroelectric power generation equipment for high-pressure power generation. When the pressure in the gas storage tank drops to the third preset value, the air in the gas storage tank is used to inject the water in the water storage tank into the low-pressure side hydroelectric power generation equipment for low-pressure power generation.

2. The compressed air energy storage power generation system according to claim 1, wherein: Before energy storage, the air compressor pre-presses the water storage tank, the gas storage tank, and the gas-water separation device, and then energy storage is carried out after pre-pressing.

3. A compressed air energy storage power generation system according to claim 1, characterized in that: Both the water storage tank and the gas storage tank are buried underground for isothermal compression; the gas-water separation device is buried underground.

4. A compressed air energy storage power generation system according to claim 1, characterized in that: During energy storage, the air flow of the air compressor and the drainage flow of the water storage tank are controlled to achieve constant-pressure drainage.

5. A compressed air energy storage power generation system according to claim 1, characterized in that: There are multiple centrifugal pumps; there are multiple water storage tanks; there are multiple gas storage tanks.

6. The compressed air energy storage power generation system according to claim 1, wherein: Valves are provided between the centrifugal pump and the water storage tank; valves are provided between the water storage tank and the gas-water separation device; valves are provided between the gas-water separation device and the gas storage tank; valves are provided between the gas storage tank and the water storage tank; valves are provided between the air compressor and the water storage tank; valves are provided between the air compressor and the gas storage tank; valves are provided between the water storage tank and the high-pressure side hydroelectric power generation equipment; valves are provided between the water storage tank and the low-pressure side hydroelectric power generation equipment.

7. A compressed air energy storage power generation method, characterized in that: The compressed air energy storage power generation method includes the following steps: Step S2: Use a centrifugal pump to inject water from the water pool into the water storage tank from the upper part of the water storage tank. When the air pressure in the water storage tank reaches the first preset value, open the valve to allow the mixed gas-liquid in the water storage tank to enter the gas-water separation device. The separated gas enters the gas storage tank, and the separated water is discharged into the water pool. After the water storage tank is filled with water, use an air compressor to send the water in the water storage tank into the low-pressure side hydroelectric power generation equipment for low-pressure power generation. Repeat the above operations until the air pressure in the gas storage tank reaches the second preset value and the water storage tank is full of water; Step S3: Use the high-pressure air in the gas storage tank to pressurize the water storage tank, and the water in the water storage tank is injected into the high-pressure side hydroelectric power generation equipment for high-pressure power generation; Step S4: When the pressure in the gas storage tank drops to the third preset value, use the remaining air in the gas storage tank to pressurize the water storage tank, and the water in the water storage tank is injected into the low-pressure side hydroelectric power generation equipment for low-pressure power generation.

8. A compressed air energy storage power generation method according to claim 7, characterized in that: The compressed air energy storage power generation method further includes: Step S1: Use an air compressor to pre-press the water storage tank, the gas-water separation device, and the gas storage tank to increase the pressure in the water storage tank, the gas-water separation device, and the gas storage tank to a certain value.

9. A compressed air energy storage power generation method according to claim 7, characterized in that: In step S2, during compression, the gas storage tank and the water storage tank exchange heat with the soil.

10. A compressed air energy storage power generation method according to claim 7, characterized in that: In step S2, during energy storage, constant-pressure drainage is achieved by controlling the air flow rate of the air compressor and the drainage flow rate of the water storage tank.

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