Hydraulic pressure and gas storage coupled compressed air energy storage system

Abstract

The utility model discloses a hydraulic pressure and air storage coupled compressed air energy storage system which comprises a compression unit, an expansion power generation unit, a first heat exchange unit, a second heat exchange unit, an air storage unit and a hydraulic unit. The gas storage unit comprises a gas storage tank, and the top of the gas storage tank is connected with the compression unit and the expansion power generation unit. The first heat exchange unit is arranged between the air storage tank and the compression unit, and the second heat exchange unit is arranged between the air storage tank and the expansion power generation unit; the bottom of the gas storage tank is connected with the hydraulic unit; according to the gas storage unit, a gas storage tank is filled with liquid in advance, so that the pressure in the gas storage tank is kept constant in the energy storage and release process, the change of the pressure borne by the gas storage tank in the energy storage and release process is extremely small, the generated alternating stress is relatively small, and the service life of the gas storage tank is greatly prolonged; the technical problem that in the prior art, a gas storage container is short in service life is solved.

Description

Technical Field

[0001] The utility model belongs to the field of electric energy storage, and relates to a compressed air energy storage system, in particular to a compressed air energy storage system. Background Art

[0002] In recent years, the compressed air energy storage technology has been vigorously developed. The basic principle of compressed air energy storage is that when the valley electricity or the redundant electricity exists, the electric energy is consumed to compress the air and store it in the gas storage chamber for preservation, so that the electric energy can be converted into compressed air; when the peak electricity or the power shortage occurs, the high-pressure air in the gas storage chamber is released and enters the expander to drive the turbine to generate electricity. Compressed air energy storage has the function of maintaining the stability of the power grid and shaving the peak and filling the valley. Its main advantages are low construction and operation costs, long service life (~30 years), environmental friendliness, and unlimited energy storage cycle. The main disadvantages are that the volume of the gas storage chamber required for air storage is huge and the pressure is relatively high. Currently, the commonly used gas storage chambers include underground salt caverns, artificial concrete chambers, and ground gas storage containers (such as pipeline steel).

[0003] Compared with the gas storage chambers of underground salt caverns and artificial concrete chambers, the ground gas storage containers (such as pipeline steel) are suitable for small-scale compressed air energy storage. However, in the existing technology, when the compressed air energy storage system of the ground gas storage container discharges the compressed air in the gas storage container, as the compressed air is discharged, the pressure of the gas storage container gradually decreases, and at the same time, the power generation efficiency of the expander also decreases. In order not to make the power generation efficiency of the expander decrease too much, the gas storage container has to retain a certain pressure (generally maintained at about 6 MPa in the existing technology), resulting in the underutilization of the volume of the gas storage container, and the power generation efficiency of the expander decreases with the decrease of the pressure. At the same time, the alternating stress generated by the change of the gas storage pressure borne by the gas storage container (such as pipeline steel) affects its service life. Summary of the Utility Model

[0004] Aiming at the deficiencies existing in the prior art, the purpose of the utility model is to provide a compressed air energy storage system with hydraulic and gas storage coupling, so as to solve the technical problems of low utilization rate of the gas storage container, low expansion power generation efficiency, and short service life of the gas storage container in the prior art.

[0005] In order to solve the above technical problems, the utility model adopts the following technical solutions to achieve:

[0006] A compressed air energy storage system with hydraulic and gas storage coupling includes a compression unit, an expansion power generation unit, a first heat exchange unit, a second heat exchange unit, a gas storage unit, and a hydraulic unit;

[0007] The gas storage unit includes a gas storage tank, and the top of the gas storage tank is respectively connected to the compression unit and the expansion power generation unit; a first heat exchange unit is arranged between the gas storage tank and the compression unit, and a second heat exchange unit is arranged between the gas storage tank and the expansion power generation unit; the bottom of the gas storage tank is connected to the hydraulic unit;

[0008] A first regulating valve is arranged between the gas storage tank and the first heat exchange unit, and a second regulating valve is arranged between the gas storage tank and the second heat exchange unit.

[0009] The present utility model further includes the following technical features:

[0010] The gas storage tank forms an acute angle with the horizontal direction.

[0011] The hydraulic unit includes a liquid storage tank, the liquid storage tank is respectively connected to the gas storage tank through a first branch and a second branch, a third regulating valve is arranged on the first branch, and a fourth regulating valve and a hydraulic pump are arranged on the second branch.

[0012] A turbo generator is arranged on the first branch.

[0013] Compared with the prior art, the beneficial technical effects of the present utility model are:

[0014] (Ⅰ) In the gas storage unit of the present utility model, by pre-filling the gas storage tank with liquid, during the energy storage and energy release processes, the pressure in the gas storage tank is ensured to be constant, so that the pressure change borne by the gas storage tank during the energy storage and energy release processes is extremely small, and the generated alternating stress is also small, greatly prolonging the service life of the gas storage tank; solving the technical problem of short service life of gas storage containers in the prior art.

[0015] (II) Through the hydraulic unit, almost all the compressed air in the gas storage tank can be discharged, and the volume of the gas storage container is utilized to the maximum; the pressure of the compressed air discharged into the expansion power generation unit is also basically constant (with less attenuation), improving the power generation efficiency of the expansion power generation unit; solving the technical problems of low utilization rate of gas storage containers and low expansion power generation efficiency in the prior art. Description of the Drawings

[0016] Figure 1 It is a schematic diagram of the mechanism of the present utility model.

[0017] The meanings of the various reference numerals in the figure are: 1 - compression unit, 2 - expansion power generation unit, 3 - heat exchange unit, 4 - gas storage unit, 5 - hydraulic unit;

[0018] 41 - first regulating valve, 42 - second regulating valve, 43 - gas storage tank;

[0019] 51 - Third regulating valve, 52 - Turbine generator, 53 - Fourth regulating valve, 54 - Hydraulic pump, 55 - Liquid storage tank.

[0020] The following further elaborates on the specific content of the present utility model in conjunction with embodiments. Specific embodiments

[0021] It should be noted that all components in the present utility model, without special instructions, are components known in the art.

[0022] The following presents specific embodiments of the present utility model. It should be noted that the present utility model is not limited to the following specific embodiments, and all equivalent transformations made on the basis of the technical solution of this application fall within the protection scope of the present utility model.

[0023] The present utility model provides a compressed air energy storage system coupling hydraulics and gas storage, including a compression unit 1, an expansion power generation unit 2, a first heat exchange unit 3 and a second heat exchange unit 6, a gas storage unit 4 and a hydraulic unit 5;

[0024] The gas storage unit 4 includes a gas storage tank 43. The top of the gas storage tank 43 is respectively connected to the compression unit 1 and the expansion power generation unit 2; a first heat exchange unit 3 is provided between the gas storage tank 43 and the compression unit 1, and a second heat exchange unit is provided between the gas storage tank 43 and the expansion power generation unit 2; the bottom of the gas storage tank 43 is connected to the hydraulic unit 5;

[0025] A first regulating valve 41 is provided between the gas storage tank 43 and the first heat exchange unit 3, and a second regulating valve 42 is provided between the gas storage tank 43 and the second heat exchange unit 6.

[0026] In the above technical solution, during energy storage, the first regulating valve 41 is opened and the second regulating valve 42 is closed. After air enters the compression unit 1 and is compressed to high temperature and high pressure, it is sent to the gas storage tank 43 after being cooled by the heat exchange unit 3. The liquid pre-filled in the gas storage tank 43 is gradually discharged to the hydraulic unit 5 by the high-pressure gas until the liquid in the gas storage tank 43 is emptied and the high-pressure air is completely stored in the gas storage tank 43. During energy release, that is, during power generation, the first regulating valve 41 is closed and the second regulating valve 42 is opened. The high-pressure air in the gas storage tank 43 is gradually discharged, enters the expansion power generation unit 2 after being heated by the heat exchange unit 3, and at the same time, the hydraulic unit 5 presses liquid into the gas storage tank 43 to reduce the attenuation of gas pressure. Finally, the liquid pushes out almost all the gas and maintains the pressure in the gas storage tank 43 basically constant.

[0027] In addition, the pressure in the gas storage tank is constant, and the pressure of the compressed air discharged into the expander is also basically constant with less attenuation, improving the power generation efficiency of the expansion power generation unit.

[0028] In the gas storage unit, by pre-filling the gas storage tank with liquid, during the energy storage and release processes, the pressure inside the gas storage tank is ensured to be constant. This makes the pressure change in the gas storage tank extremely small during the energy storage and release processes, resulting in relatively small alternating stress and greatly extending the service life of the gas storage tank; it solves the technical problem of the short service life of gas storage containers in the prior art.

[0029] Through the hydraulic unit, almost all the compressed air in the gas storage tank can be discharged, and the volume of the gas storage container is utilized to the maximum; the pressure of the compressed air discharged to the expansion power generation unit also basically remains constant with little attenuation, improving the power generation efficiency of the expansion power generation unit; it solves the technical problems of low utilization rate of gas storage containers and low expansion power generation efficiency in the prior art.

[0030] Specifically, the gas storage tank 43 forms an acute angle with the horizontal direction.

[0031] In the above technical solution, the gas storage tank 43 is arranged at an acute angle, which is beneficial to emptying the liquid in the gas storage tank.

[0032] Specifically, the hydraulic unit 5 includes a liquid storage tank 55. The liquid storage tank 55 is respectively connected to the gas storage tank 43 through a first branch 56 and a second branch 57. A third regulating valve 51 is arranged on the first branch 56, and a fourth regulating valve 53 and a hydraulic pump 54 are arranged on the second branch 57.

[0033] In the above technical solution, by using the hydraulic pump 54 in the hydraulic unit 5 to fill the liquid, almost all the compressed air in the gas storage unit 4 can be discharged, and the volume of the gas storage tank 43 is utilized to the maximum;

[0034] Through the hydraulic unit, almost all the compressed air in the gas storage tank can be discharged, and the volume of the gas storage container is utilized to the maximum; the pressure of the compressed air discharged to the expansion power generation unit also basically remains constant with little attenuation, improving the power generation efficiency of the expansion power generation unit; it solves the technical problems of low utilization rate of gas storage containers and low expansion power generation efficiency in the prior art.

[0035] Specifically, a turbo generator 52 is arranged on the first branch 56.

[0036] In the above technical solution, the turbo generator 52 can recover and generate electricity from the energy of the high-pressure water discharged from the gas storage unit 4.

[0037] The present utility model also provides a method for compressed air energy storage by coupling hydraulic pressure and gas storage, including an energy storage stage and an energy release stage;

[0038] The energy storage stage specifically includes the following steps:

[0039] Step 1, use the hydraulic pump 54 to pre-fill the gas storage tank 43 with liquid;

[0040] Step 2: Air enters the compression unit 1 for compression, and the compressed high-temperature and high-pressure air is transported to the first heat exchange unit 3 for cooling to obtain cooled high-pressure air.

[0041] Step 3: Open the first regulating valve 41 and the third regulating valve 51, and close the second regulating valve 42 and the fourth regulating valve 53. Transport the cooled high-pressure air obtained in Step 2 to the gas storage tank 43 of the gas storage unit 4. The liquid in the gas storage tank 43 is gradually discharged to the hydraulic unit 5 through the first branch 56 by the high-pressure air until the liquid in the gas storage tank 43 is emptied and the gas storage tank 43 is filled with high-pressure gas.

[0042] The energy release stage specifically includes the following steps:

[0043] Step 1: Close the first regulating valve 41 and the third regulating valve 51, and open the second regulating valve 42 and the fourth regulating valve 53. The high-pressure air in the gas storage tank 43 is gradually discharged and enters the second heat exchange unit 6 for heating to obtain heated air.

[0044] Step 2: Send the heated air obtained in Step 1 into the expansion power generation unit 2. At the same time, the hydraulic unit 5 presses the liquid into the gas storage tank 43 through the second branch until the gas storage tank 43 is filled with liquid.

Claims

1. A compressed air energy storage system coupled with hydraulic pressure and gas storage, characterized in that: It comprises a compression unit (1), an expansion power generation unit (2), a first heat exchange unit (3), a second heat exchange unit (6), a gas storage unit (4) and a hydraulic unit (5); The gas storage unit (4) comprises a gas storage tank (43), the top of which is connected to the compression unit (1) and the expansion power generation unit (2) respectively; the first heat exchange unit (3) is arranged between the gas storage tank (43) and the compression unit (1), and the second heat exchange unit is arranged between the gas storage tank (43) and the expansion power generation unit (2); the bottom of the gas storage tank (43) is connected to the hydraulic unit (5); A first regulating valve (41) is provided between the gas storage tank (43) and the first heat exchange unit (3), and a second regulating valve (42) is provided between the gas storage tank (43) and the second heat exchange unit (6).

2. The compressed air energy storage system with hydraulic and gas storage coupling as claimed in claim 1, characterized in that: The gas storage tank (43) forms an acute angle with the horizontal direction.

3. The compressed air energy storage system coupled with hydraulic pressure and gas storage as claimed in claim 1, characterized in that: The hydraulic unit (5) comprises a liquid storage tank (55), the liquid storage tank (55) being connected to the gas storage tank (43) via a first branch (56) and a second branch (57), respectively; a third regulating valve (51) is arranged on the first branch (56), and a fourth regulating valve (53) and a hydraulic pump (54) are arranged on the second branch (57).

4. The compressed air energy storage system with hydraulic and gas storage coupling as claimed in claim 3, characterized in that: The first branch (56) is provided with a turbine generator (52).

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