Pressure-staged hydraulic compressed air energy storage system and operation method

Abstract

The present invention belongs to the technical field of energy storage. Disclosed are a pressure-staged hydraulic compressed air energy storage system and an operation method. In the system, a high-pressure gas storage vessel serves as an energy storage vessel, and steam-water mixing vessels serve as work-doing vessels, the high-pressure gas storage vessel being separately connected to the plurality of steam-water mixing vessels, and the steam-water mixing vessels being connected to a water storage tank by means of an energy conversion apparatus. In a power generation process, as a power generation pressure decreases, the volume of the high-pressure gas storage vessel continuously expands, and all the steam-water mixing vessels are converted into new energy storage vessels to expand the volume of the energy storage vessel, thereby breaking through the constraint that the pressure of energy storage vessels and the pressure of work-doing vessels must be equal, achieving the decoupling between the pressure of energy storage vessels and the pressure of work-doing vessels, and remarkably reducing the demand of work-doing vessels in energy storage systems for large-volume high-pressure vessels. The system utilizes the compression and expansion of air to achieve energy storage and power generation, thereby achieving energy storage-power generation without geographical elevation differences, and having the advantage of flexible arrangement.

Description

A pressure-graded hydraulic compressed air energy storage system and its operation method Technical Field

[0001] This invention belongs to the field of energy storage technology, specifically relating to a pressure-graded hydraulic compressed air energy storage system. Background Technology

[0002] Power systems dominated by new energy sources will become a common phenomenon in various regions. However, the volatility, randomness, and uncertainty of new energy sources pose serious challenges to the safe and stable operation of power systems. The widening peak-valley difference in power grids further exacerbates this problem, significantly increasing the demand for flexible regulation resources. Therefore, advanced large-scale energy storage technologies are urgently needed to address the integration of renewable energy into conventional power systems and regional energy systems, thereby improving their efficiency, security, and economy. Compressed air energy storage, with its advantages of large capacity, long lifespan, cleanliness, safety, reliability, and good economics, is one of the key technologies supporting the large-scale development of renewable energy and ensuring energy security.

[0003] Currently, existing non-combustion compressed air energy storage systems use air as both the working medium and the storage medium, resulting in a start-up and shutdown process that takes more than ten minutes and a slow power increase / decrease rate. Hydraulic compressed air energy storage systems use water as the working medium and air as the storage medium, but the pressure of the working container needs to be determined based on the pressure of the storage container. This leads to a high proportion of the cost of large-capacity working containers in the system, necessitating improvements in system economics and making it difficult to meet the demands of high-power energy storage.

[0004] It is evident that existing hydraulic compressed air energy storage systems, where the pressure of the energy storage container determines the pressure of the work container, are coupled and thus cannot meet the demands of high-power energy storage. Summary of the Invention

[0005] The purpose of this invention is to provide a pressure-graded hydraulic compressed air energy storage system to solve the problem that existing hydraulic compressed air energy storage systems, where the pressure of the energy storage container determines the pressure of the work container, have a coupled relationship, making it difficult to meet the needs of high-power energy storage.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A pressure-graded hydraulic compressed air energy storage system includes a high-pressure air storage container;

[0008] The high-pressure gas storage container is connected to multiple steam-water mixing containers, and the multiple steam-water mixing containers are connected in sequence.

[0009] Each steam-water mixing container is connected to an energy conversion device, which is used to replenish the water medium into the steam-water mixing container during the energy storage phase and to convert the kinetic energy from the water medium into electrical energy during the power generation phase.

[0010] The energy conversion device is connected to a water storage tank.

[0011] Furthermore, multiple soda-mixing containers are used, each with different pressure ratings and volumes.

[0012] Furthermore, both the high-pressure gas storage container and the gas-water mixing container are closed containers.

[0013] Furthermore, the energy conversion device includes a water turbine and a pump respectively connected to the water storage tank;

[0014] The inlet of the steam-water mixing container is connected to the output end of the pump;

[0015] The drain outlet of the steam-water mixing container is connected to the input end of the water turbine;

[0016] The input end of the pump is coaxially connected to the water pump motor;

[0017] The output end of the water turbine is coaxially connected to the generator.

[0018] Furthermore, the energy conversion device adopts a water pump turbine connected to the water storage tank; the steam-water mixing container is provided with a two-way port and is connected to the water pump turbine through the two-way port; the output end of the water pump turbine is coaxially connected to the generator.

[0019] Furthermore, the high-pressure gas storage container is connected to the steam-water mixing container via a first valve.

[0020] Furthermore, multiple soda-mixing containers are connected in sequence via a second valve.

[0021] Furthermore, the soda-water mixing container is equipped with an atomizing spray device, which is connected to the water supply end of the energy conversion device.

[0022] An operation method for a pressure-graded hydraulic compressed air energy storage system, based on the aforementioned pressure-graded hydraulic compressed air energy storage system, includes:

[0023] During the power generation stage, the high-pressure gas storage container replenishes the gas-water mixing container with gas. The gas expands and causes the water medium in the gas-water mixing container to be discharged. The energy conversion device converts the kinetic energy of the water medium into electrical energy, and the water medium is discharged into the water storage tank after passing through the energy conversion device.

[0024] During the energy storage phase, the energy conversion equipment replenishes the water medium from the water storage tank to the steam-water mixing container until both the steam-water mixing container and the high-pressure gas storage container reach the corresponding preset pressure values.

[0025] Furthermore, multiple carbonated beverage mixing containers are used, each with different pressure ratings and volumes.

[0026] During the power generation phase, the high-pressure gas storage container replenishes gas to the steam-water mixing container in order of pressure level from high to low, and connects all the gas-water mixing containers after replenishment to the high-pressure gas storage container to form a new high-pressure gas storage container.

[0027] During the energy storage phase, the energy conversion equipment replenishes the water working medium to the steam-water mixing container in order of increasing pressure level, and performs atomized spraying to reduce the temperature of the compressed air until both the steam-water mixing container and the high-pressure gas storage container reach the corresponding preset pressure value.

[0028] Compared with existing technologies, the present invention has the following beneficial effects:

[0029] This invention provides a pressure-graded hydraulic compressed air energy storage system. In this system, a high-pressure air storage container serves as the energy storage container, and a steam-water mixing container serves as the power storage container. The high-pressure air storage container is connected to multiple steam-water mixing containers, which are connected to a water storage tank via an energy conversion device. During power generation, as the power generation pressure decreases, the volume of the high-pressure air storage container continuously expands. All steam-water mixing containers are transformed into new energy storage containers, increasing the volume of the energy storage containers and overcoming the constraint that the pressure of the energy storage container must be equal to that of the power storage container. This achieves decoupling between the pressures of the energy storage container and the power storage container, significantly reducing the large volume requirement of the high-pressure pressure container for the power storage container in the energy storage system. This system achieves energy storage and power generation through the compression and expansion of air, realizing energy storage-power generation without terrain elevation differences, and has the advantage of flexible layout. Furthermore, the energy storage medium is air, and the power storage medium is water, both clean and pollution-free working fluids, achieving green and clean energy storage.

[0030] Preferably, in this invention, multiple steam-water mixing containers with different pressure levels and volumes are used to store and release energy during large pressure changes, which significantly reduces the container cost in the energy storage and power generation process and improves the technical and economic efficiency of the entire system; at the same time, it also improves the overall operating efficiency and safety of the system.

[0031] Preferably, in this invention, both the high-pressure gas storage container and the gas-water mixing container adopt a closed container design, that is, the gas in the high-pressure gas storage container and each gas-water mixing container does not directly contact the atmospheric environment. This design can prevent leakage of gas and water working fluid, reduce energy loss, and improve the system's sealing performance and operating efficiency.

[0032] Preferably, in this invention, the turbine and pump, as energy conversion devices, have high reliability and stability, which can ensure the efficient operation of the system in the process of hydropower generation and energy storage.

[0033] Preferably, in this invention, the energy conversion device adopts a water pump turbine, which has the dual functions of pumped water storage and hydropower generation. It can achieve seamless switching between energy storage and power generation stages, improving the system integration and operating efficiency. At the same time, it can operate efficiently in both high-pressure and low-pressure systems, solving the problem that pressure changes seriously affect the system's circulation efficiency.

[0034] Preferably, in this invention, the high-pressure gas storage container is connected to the steam-water mixing container through a first valve. The first valve not only allows the steam-water mixing container and the high-pressure gas storage container to connect and form a new gas storage container during the power generation process, but also controls the gas flow between the high-pressure gas storage container and the steam-water mixing container, thereby achieving flexible control and safe isolation of the system.

[0035] Preferably, in this invention, multiple steam-water mixing containers are connected in sequence via a second valve. The second valve can control the water flow and gas pressure balance between different steam-water mixing containers, ensuring the stable operation of the system during the power generation and energy storage phases.

[0036] Preferably, in this invention, an atomizing spray device is provided inside the gas-water mixing container. The atomizing spray device can uniformly spray the water working medium into the gas-water mixing container, improve the gas-water mixing efficiency, and reduce energy loss. During the compression and expansion processes, the forced heat exchange technology of atomizing spray is adopted, which achieves the effect of approximately constant air temperature during the energy storage and power generation processes, thus solving the problems of excessive temperature rise and low energy storage efficiency in compressed air energy storage.

[0037] This invention also provides an operation method for a pressure-graded hydraulic compressed air energy storage system. Based on the aforementioned pressure-graded hydraulic compressed air energy storage system, in the power generation stage, this method utilizes a high-pressure gas storage container to replenish gas to the steam-water mixing container, causing the gas to expand and expel the water working medium from the steam-water mixing container. Then, the kinetic energy of the water working medium is converted into electrical energy through an energy conversion device. In the energy storage stage, the energy conversion device replenishes the water working medium from the reservoir to the steam-water mixing container until both the steam-water mixing container and the high-pressure gas storage container reach their respective preset pressure values. This ensures the stable operation of the entire pressure-graded hydraulic compressed air energy storage system, breaks through the constraint that the pressure of the energy storage container must be equal to the pressure of the working container, and achieves the decoupling of the pressure of the energy storage container and the pressure of the working container. This significantly reduces the demand for a large-volume high-pressure pressure container in the energy storage system.

[0038] Preferably, in this invention, the method involves the following steps: During the power generation stage, the high-pressure gas storage container sequentially replenishes the gas-water mixing container with gas in descending order of pressure level, connecting all the replenished gas-water mixing containers to the high-pressure gas storage container to form a new high-pressure gas storage container; During the energy storage stage, the energy conversion equipment sequentially replenishes the gas-water mixing container with water in ascending order of pressure level, performing atomized spraying to reduce the temperature of the compressed air, until both the gas-water mixing container and the high-pressure gas storage container reach the corresponding preset pressure value; This ensures stable system operation while taking into account the overall technical and economic efficiency of the system, greatly saving system operating costs. Attached Figure Description

[0039] Figure 1 is a structural schematic diagram of a pressure-graded hydraulic compressed air energy storage system provided by the present invention;

[0040] Figure 2 is a schematic diagram of a pressure-graded hydraulic compressed air energy storage system provided in an embodiment of the present invention;

[0041] Figure 3 is a schematic diagram of another pressure-graded hydraulic compressed air energy storage system provided in an embodiment of the present invention;

[0042] Figure 4 is a structural schematic diagram of another pressure-graded hydraulic compressed air energy storage system provided in an embodiment of the present invention.

[0043] Reference numerals: High-pressure gas storage container-1; Gas-water mixing container-2; First gas-water mixing container-2-1; Second gas-water mixing container-2-2; Third gas-water mixing container-2-3; Water turbine-3; Pump-4; Reservoir-5; Water pump-turbine-6; First valve-7; Second valve-8; Third valve-9; Fourth valve-10; Fifth valve-11. Detailed Implementation

[0044] To make the technical problems solved by the present invention, the technical solutions, and the beneficial effects clearer, the following specific embodiments provide a further detailed description of the present invention. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of the invention.

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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 some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0046] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0047] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0048] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0049] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0050] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0051] Example 1

[0052] As mentioned in the background technology, existing non-combustion compressed air energy storage uses air as both the working medium and the storage medium, and the start-up and shutdown process takes more than 10 minutes, with slow power increase and decrease rates. Hydraulic compressed air energy storage uses water as the working medium and air as the storage medium, but the pressure of the working container needs to be determined according to the pressure of the storage container, resulting in a high proportion of the cost of the large-capacity working container in the system. The system's economic efficiency urgently needs to be improved, and it is difficult to meet the demand for high-power energy storage.

[0053] To address the aforementioned issues, this embodiment provides a pressure-graded hydraulic compressed air energy storage system. This system and method overcome the drawbacks of non-combustion compressed air energy storage systems and hydraulic compressed air energy storage systems where the energy storage container and the power container cannot be separated. It also breaks through the constraint that the pressure of the energy storage container and the pressure of the power container must be equal, and overcomes the problem of poor system technical and economic efficiency due to the high cost of the power container, making it difficult to achieve short-term high-power energy storage.

[0054] As shown in Figure 1, the present invention provides a pressure-graded hydraulic compressed air energy storage system, including a high-pressure air storage container 1, multiple air-water mixing containers 2, an energy conversion device, a water storage tank 5, valves, and several pipelines.

[0055] As shown in Figure 1, the energy conversion equipment includes a water turbine 3 and a pump 4; the specific connection structure of this pressure-graded hydraulic compressed air energy storage system is as follows:

[0056] The high-pressure gas storage container is connected to N gas-water mixing containers 2 via the first valve 7, namely gas-water mixing containers G1, G2...G N (1≤N≤200000), Soft drink mixing container G N-1 Container G for mixing with soda N The two-way connection is achieved through the second valve 8, and the soda-water mixing container G is connected in pairs. i (1≤i≤N) is connected to the turbine manifold via the third valve 9, the turbine manifold is connected to the turbine inlet, and the turbine outlet is connected to the reservoir 5; the steam-water mixing container G i (1≤i≤N) The pump is connected to the water pump manifold through the fourth valve 10. The water pump manifold is connected to the outlet of the pump 4. The inlet of the pump 4 is connected to the water storage tank 5. The water turbine 3 is coaxially connected to the generator. The pump 4 is coaxially connected to the water pump motor.

[0057] As can be seen, the above design of this system, with the high-pressure gas storage container as the energy storage container and the gas-water mixing container as the work container, breaks through the constraint that the pressure of the energy storage container and the pressure of the work container must be equal, and realizes the mutual decoupling of the pressure of the energy storage container and the pressure of the work container.

[0058] This embodiment also provides the working principle of a pressure-graded hydraulic compressed air energy storage system:

[0059] During the power generation stage, the high-pressure gas storage container 1 replenishes the gas-water mixing container 2 with gas. The gas expands and causes the water working medium in the gas-water mixing container 2 to be discharged. The energy conversion device converts the kinetic energy of the water working medium into electrical energy. The water working medium is discharged into the water storage tank 5 after passing through the energy conversion device.

[0060] During the energy storage phase, the energy conversion device replenishes the water medium in the water storage tank 5 to the steam-water mixing container 2 until both the steam-water mixing container 2 and the high-pressure gas storage container 1 reach the corresponding preset pressure value.

[0061] As shown in Figure 2, in this embodiment, the carbonated beverage mixing container 2 uses a first carbonated beverage mixing container 2-1, a second carbonated beverage mixing container 2-2, and a third carbonated beverage mixing container 2-3. Here, the first carbonated beverage mixing container 2-1, the second carbonated beverage mixing container 2-2, and the third carbonated beverage mixing container 2-3 can be of the same model and specifications, that is, containers with the same pressure rating and the same volume. Of course, in this embodiment, in order to take into account the technical and economic efficiency of the entire system, the first carbonated beverage mixing container 2-1, the second carbonated beverage mixing container 2-2, and the third carbonated beverage mixing container 2-3 use carbonated beverage mixing containers with different pressure ratings to realize the storage and release of energy during large pressure changes.

[0062] As shown in Figure 2, in this embodiment, the pressure levels of the first soft drink mixing container 2-1, the second soft drink mixing container 2-2, and the third soft drink mixing container 2-3 are as follows: G1>G2>G3; where G1 represents the first soft drink mixing container 2-1; G2 represents the second soft drink mixing container 2-2; and G3 represents the third soft drink mixing container 2-3.

[0063] This embodiment provides a working method for a pressure-graded hydraulic compressed air energy storage system, as detailed below:

[0064] During the power generation process, as the power generation pressure decreases, the volume of the high-pressure gas storage container continuously expands. The power generation process ends when the volume of all the working containers is converted into the energy storage container.

[0065] During the first power generation process, the high-pressure gas storage container first replenishes the gas in the high-pressure steam-water mixing container G1. After expansion and power generation, the steam-water mixing container G1 is connected to the high-pressure gas storage container to form a new high-pressure gas storage container.

[0066] When the gas-water mixing container G1 is about to reach the minimum liquid level or the set pressure, the second power generation process begins. The high-pressure gas storage container and the gas-water mixing container G1 replenish the pressurized gas in the lower-pressure gas-water mixing container G2. After expansion and power generation, the gas-water mixing containers G1 and G2 are connected to the high-pressure gas storage container to form a new high-pressure gas storage container.

[0067] The high-pressure gas storage container and the steam-water mixing container G1, G2, and G3 are connected. After expansion and power generation, the steam-water mixing container G1, G2, and G3 are all connected to the high-pressure gas storage container to form a high-pressure gas storage container, and the power generation process ends.

[0068] During the energy storage process, pump 4 first replenishes the low-pressure steam-water mixing container G3 with liquid. At this time, the high-pressure gas storage container and each steam-water mixing container G3, G2, and G1 are connected to each other. After the gas pressure in the low-pressure steam-water mixing container G3 reaches the set value, the valve is closed, and the connection with the water storage tank and other containers is cut off. Then, the water pump is used to pump water and pressurize the low-pressure steam-water mixing container G2 in sequence. The high-pressure gas storage container and each steam-water mixing container G3, G2, and G1 are connected until the gas pressure in the steam-water mixing container G1 reaches the set value. Then, the valve is closed, and the connection with the water storage tank and other containers is cut off. This process is repeated until the third energy storage. Before the energy storage, the high-pressure gas storage container and the steam-water mixing container G1 are connected. After the water pump pumps water and pressurizes the steam-water mixing container G1, the gas pressure in the high-pressure gas storage container reaches the set value, and the energy storage process ends.

[0069] This example uses only three containers. If the entire system uses multiple water-soda mixing containers, the specific operating method is the same as described above.

[0070] Example 2

[0071] This embodiment provides another pressure-graded hydraulic compressed air energy storage system, with the same structure as Embodiment 1. The difference lies in the further optimization and improvement based on the structure of Embodiment 1, specifically including:

[0072] As shown in Figure 3, in this embodiment, the energy conversion device includes a water turbine 3 and a pump 4. Each steam-water mixing container is provided with a bidirectional port, which serves as both a water inlet and a water outlet. The bidirectional port is connected to the water turbine 3 and the pump 4 respectively through branch pipes of the confluence pipe. The valve is simplified to a fifth valve 11. The above structural design simplifies the construction of the system, which not only facilitates the maintenance and operation of the system, but also saves the operating cost of the entire system.

[0073] Example 3

[0074] This embodiment provides another pressure-graded hydraulic compressed air energy storage system, with the same structure as Embodiment 2. The difference lies in the further optimization and improvement based on the structure of Embodiment 2, specifically including:

[0075] As shown in Figure 4, in this embodiment, the energy conversion device adopts a water pump turbine 6; the water pump turbine 6 has the dual functions of pumped water storage and hydropower generation, and can achieve seamless switching between energy storage and power generation stages, improving the system integration and operating efficiency; at the same time, it can operate efficiently in both high-pressure and low-pressure systems, solving the problem that pressure changes seriously affect the system's circulation efficiency.

[0076] Furthermore, in the above embodiments, both the high-pressure gas storage container 1 and the steam-water mixing container 2 adopt a closed container design, that is, the gas in the high-pressure gas storage container 1 and each steam-water mixing container 2 does not directly contact the atmospheric environment. This design can prevent leakage of gas and water working fluid, reduce energy loss, and improve the sealing performance and operating efficiency of the system.

[0077] Furthermore, in the above embodiments, an atomizing spray device can be installed inside the gas-water mixing container 2. The atomizing spray device can uniformly spray the water working medium into the gas-water mixing container, improve the gas-water mixing efficiency, and reduce energy loss. During the compression and expansion processes, the forced heat exchange technology of atomizing spray is adopted, which achieves the effect of approximately constant air temperature during the energy storage and power generation processes, thus solving the problems of excessive temperature rise and low energy storage efficiency in compressed air energy storage.

[0078] In summary, this invention provides a pressure-graded hydraulic compressed air energy storage system, which has the following advantages compared to existing hydraulic compressed air energy storage systems:

[0079] a) This invention achieves energy storage and power generation through the compression and expansion of air, realizing energy storage and power generation without terrain difference, and has the advantage of flexible layout.

[0080] b) This invention achieves the decoupling of the pressure of the energy storage container and the pressure of the working container, which significantly reduces the demand for large-volume high-pressure pressure vessels in the working container of the energy storage system.

[0081] c) This invention uses multiple containers with different pressures and volumes to store and release energy during large pressure changes, which significantly reduces the container cost in energy storage and power generation and improves the technical and economic efficiency of the system.

[0082] d) The working medium of this invention is water, and the energy conversion device is a pump / water turbine, which can operate with high efficiency in both high-pressure and low-pressure systems, thus solving the problem that pressure changes seriously affect the system's circulation efficiency.

[0083] e) By employing forced heat exchange technologies such as atomized spraying during the compression and expansion processes of this invention, the air temperature remains approximately constant during the energy storage and power generation processes, thus solving the problems of excessive temperature rise and low energy storage efficiency in compressed air energy storage.

[0084] f) The energy storage medium of this invention is air, and the working medium is water, both of which are clean and pollution-free working fluids, thus realizing green and clean energy storage.

[0085] g) This invention contains no flammable or explosive substances at room temperature, thus fundamentally solving the safety operation problem of energy storage systems that are prone to fire and explosion.

[0086] h) This invention can not only cooperate with thermal power units for thermal power-storage frequency regulation operation, but also undertake high-frequency automatic power generation control and regulation of thermal power units.

[0087] i) The working medium of this invention is water, which is incompressible. It has the advantages of fast start-up and shutdown of water pumps and water turbines and short switching time. The energy storage system has the advantage of rapid switching between energy storage and power generation conditions.

[0088] The above embodiments are merely one of the implementation methods for achieving the technical solution of the present invention. The scope of protection claimed by the present invention is not limited to this embodiment, but also includes any variations, substitutions and other implementation methods that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention.

Claims

1. A pressure-staged hydro-compressed air energy storage system, characterized by, The high-pressure gas storage container (1) is connected with a plurality of steam-water mixing containers (2) respectively, and the steam-water mixing containers (2) are sequentially connected with each other. Each steam-water mixing container (2) is connected with an energy conversion device, which is used for supplementing water working substance into the steam-water mixing container (2) in an energy storage stage and converting kinetic energy from the water working substance into electric energy in a power generation stage. The energy conversion device is connected with a water storage pool (5). The steam-water mixing containers (2) are steam-water mixing containers with different pressure levels and different volumes.

2. A pressure-staged hydro-compressed air energy storage system according to claim 1, characterized in that, The high-pressure gas storage container (1) and the steam-water mixing container (2) are closed containers.

3. A pressure staged hydro compressed air energy storage system according to claim 1, wherein, The energy conversion device comprises a water turbine (3) and a pump (4) connected with the water storage pool (5) respectively.

4. A pressure staged hydro compressed air energy storage system according to claim 1, wherein, The water inlet of the steam-water mixing container (2) is connected with the output end of the pump (4). The water outlet of the steam-water mixing container (2) is connected with the input end of the water turbine (3). The input end of the pump (4) is coaxially connected with a water pump motor. The output end of the water turbine (3) is coaxially connected with a generator. The energy conversion device is a pump-turbine (6) connected with the water storage pool (5), the steam-water mixing container (2) is provided with a bidirectional port and is connected with the pump-turbine (6) through the bidirectional port, and the output end of the pump-turbine (6) is coaxially connected with a generator.

5. A pressure staged hydro compressed air energy storage system according to claim 1, wherein, The high-pressure gas storage container (1) is connected with the steam-water mixing container (2) through a first valve (7).

6. A pressure staged hydro compressed air energy storage system according to claim 1, wherein, The steam-water mixing containers (2) are sequentially connected with each other through a second valve (8).

7. A pressure staged hydro compressed air energy storage system according to claim 1, wherein, The steam-water mixing container is provided with an atomizing and spraying device, and the atomizing and spraying device is communicated with a water supply end of the energy conversion device.

8. A pressure staged hydro compressed air energy storage system according to claim 1, wherein, The pressure-staged hydraulic compressed air energy storage system based on claims 1-8 comprises:

9. A method of operating a pressure-staged hydro-compressed air energy storage system, characterized by, In the power generation stage, the high-pressure gas storage container (1) supplements gas to the steam-water mixing container (2), the gas is expanded to make the water working substance in the steam-water mixing container (2) be discharged, the kinetic energy from the water working substance is converted into electric energy by the energy conversion device, and the water working substance is discharged into the water storage pool (5) through the energy conversion device; In the energy storage stage, the energy conversion device supplements the water working substance in the water storage pool (5) to the steam-water mixing container (2) until the steam-water mixing container (2) and the high-pressure gas storage container (1) reach corresponding preset pressure values. The steam-water mixing containers (2) are steam-water mixing containers with different pressure levels and different volumes.

10. A method of operating a pressure-staged hydro-compressed air energy storage system according to claim 9, characterized in that, In the power generation stage, the high-pressure gas storage container (1) supplements gas to the steam-water mixing containers (2) in sequence from high to low pressure levels, the steam-water mixing containers (2) after being supplemented with gas are communicated with the high-pressure gas storage container (1), and a new high-pressure gas storage container is formed; In the energy storage stage, the energy conversion device supplements the water working substance to the steam-water mixing containers (2) in sequence from low to high pressure levels, atomizing and spraying are performed to reduce the temperature of the compressed air, and until the steam-water mixing containers (2) and the high-pressure gas storage container (1) reach corresponding preset pressure values. ​

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