Compressed air energy storage system

Abstract

The invention provides a compressed air energy storage system which comprises an air compressor set used for compressing air, an underground air storage facility set used for storing the compressed air, a first liquid storage tank, a hydraulic generator set, a second liquid storage tank and an air turbine generator set. And liquid in the second liquid storage tank is pressed into the hydraulic generator set so that the hydraulic generator set can generate electricity, the liquid leaving the hydraulic generator set enters the second liquid storage tank, air in the second liquid storage tank is pressed into the air turbine generator set so that the air turbine generator set can generate electricity. The system can be suitable for high-pressure deep stratums, and a larger application range and higher system circulation efficiency are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of deep formation oil and gas energy storage, and in particular to a compressed air energy storage system. Background Art

[0002] Compressed air energy storage is a physical energy storage technology that can achieve large-scale electrical energy storage. Existing compressed air energy storage technology uses electricity to drive air compressors to store compressed air in enclosed spaces such as underground salt caverns, chambers, mine tunnels, shallow saline layers, and releases compressed air when power generation is needed to drive air turbines to generate electricity. Against the background of the rapid development of installed capacity of renewable energy power generation such as wind power and photovoltaic power generation, compressed air energy storage technology has received increasing attention in order to effectively utilize renewable energy for power generation.

[0003] In order to further expand the application of compressed air energy storage technology, depleted oil and gas reservoirs in deep formations, or other permeable formations in deep formations, can be used as storage space for compressed air. This can reduce dependence on special geological conditions such as salt caverns and build more compressed air energy storage systems. At the same time, deep formations can withstand higher pressures, which can achieve higher energy storage cycle efficiency and enable more renewable energy generation to be effectively utilized. In addition, deep permeable formations have higher formation fluid pressures, which can enable compressed air energy storage systems to reach higher working pressures and improve their system cycle efficiency.

[0004] The main obstacle to building a compressed air energy storage system using deep high-pressure formations is that the maximum pressure that an air turbine generator set can withstand is limited (about 35MPa), and the original pore fluid pressure of many deep high-pressure formations is higher than this upper limit. In order to avoid instability and collapse of the formation rock mass, the formation fluid pressure should not be lower than the original pore fluid pressure for a long time. Therefore, the compressed air stored in deep high-pressure formations needs to be maintained at a relatively high pressure. The original pore fluid pressure of the formation can be used as the upper limit of the pressure of compressed air storage, and the lower limit of the storage pressure is about 10 to 20MPa lower than this pressure. Under this limited condition, the existing technology mostly uses a pressure reducing valve to reduce the pressure of the compressed gas to a range that the air turbine generator set can withstand, and then uses the compressed air after the pressure reduction to generate electricity, which results in a large amount of pressure potential energy waste and reduces the system circulation efficiency.

[0005] In order to solve the problem that the existing compressed air energy storage system cannot utilize deep well formations with formation pore pressure greater than 35MPa, it is urgently necessary to provide a compressed air energy storage system that can be applied to high-pressure deep formations to achieve a wider range of applications and higher system circulation efficiency. Summary of the invention

[0006] One object of the present invention is to provide a compressed air energy storage system that can be applied to high-pressure deep formations to achieve a wider range of applications and higher system cycle efficiency.

[0007] According to the present invention, a compressed air energy storage system includes an air compressor unit for compressing air, an underground gas storage facility unit for storing compressed air, a first liquid storage tank, a hydraulic generator unit, a second liquid storage tank and an air turbine generator unit. The compressed air in the underground gas storage facility unit enters the first liquid storage tank, and the liquid therein is pressed into the hydraulic generator unit so that the hydraulic generator unit generates electricity. The liquid leaving the hydraulic generator unit enters the second liquid storage tank, and the air therein is pressed into the air turbine generator unit so that the air turbine generator unit generates electricity.

[0008] In a preferred embodiment, the compressed air in the underground gas storage facility group can also enter the second liquid storage tank and press the liquid therein into the hydraulic generator set so that the hydraulic generator set generates electricity, and the liquid leaving the hydraulic generator set enters the first liquid storage tank and presses the air therein into the air turbine generator set so that the air turbine generator set generates electricity.

[0009] In a preferred embodiment, both the first liquid storage tank and the second liquid storage tank have an oil layer above the internal liquid layer.

[0010] In a preferred embodiment, the compressed air energy storage system further comprises a heat storage device having a heat storage fluid therein, wherein the heat storage fluid can flow from the heat storage device to the air compressor unit and absorb heat therein before flowing back to the heat storage device.

[0011] In a preferred embodiment, the heat storage fluid can also flow from the heat storage device to the air turbine generator set and, after releasing heat therein, flow back to the heat storage device.

[0012] In a preferred embodiment, the compressed air energy storage system includes a main gas inflow pipeline and two branch gas inflow pipelines. The underground gas storage facility group is connected to the main gas inflow pipeline. The main gas inflow pipeline is respectively connected to the first liquid storage tank and the second liquid storage tank through the two branch gas inflow pipelines. The two branch gas inflow pipelines are respectively provided with a first gas valve and a second gas valve.

[0013] In a preferred embodiment, the compressed air energy storage system also includes a main gas outflow pipe and two branch gas outflow pipes, the first liquid storage tank and the second liquid storage tank are connected to the main gas outflow pipe through the two branch gas outflow pipes respectively, and the two branch gas outflow pipes are respectively provided with a third gas valve and a fourth gas valve, and the main gas outflow pipe is connected to the air turbine generator set.

[0014] In a preferred embodiment, the compressed air energy storage system also includes a first liquid flow pipeline and a second liquid flow pipeline. The first liquid storage tank and the second liquid storage tank are connected to the liquid input end of the hydraulic generator through the first liquid flow pipeline and the second liquid flow pipeline, respectively. The first liquid flow pipeline and the second liquid flow pipeline are respectively provided with a first liquid valve and a second liquid valve.

[0015] In a preferred embodiment, the compressed air energy storage system also includes a third liquid flow pipeline and a fourth liquid flow pipeline, the first liquid storage tank and the second liquid storage tank are connected to the liquid output end of the hydraulic generator through the third liquid flow pipeline and the fourth liquid flow pipeline respectively, and the third liquid flow pipeline and the fourth liquid flow pipeline are respectively provided with a third liquid valve and a fourth liquid valve.

[0016] In a preferred embodiment, the compressed air energy storage system also includes a control device, and the control device is electrically connected to the first liquid valve, the second liquid valve, the third liquid valve, the fourth liquid valve, the first gas valve, the second gas valve, the third gas valve and the fourth gas valve.

[0017] The present invention includes an air compressor unit for compressing air, an underground gas storage facility unit for storing compressed air, a first liquid storage tank, a hydraulic generator unit, a second liquid storage tank and an air turbine generator unit. The compressed air in the underground gas storage facility unit enters the first liquid storage tank and presses the liquid therein into the hydraulic generator unit, so that the hydraulic generator unit generates electricity. The liquid leaving the hydraulic generator unit enters the second liquid storage tank and presses the air therein into the air turbine generator unit, so that the air turbine generator unit generates electricity. The high-pressure compressed air can be used to continuously drive the liquid in the first liquid storage tank to flow through the hydraulic generator unit. The hydraulic generator unit can convert part of the pressure potential energy of the liquid into electrical energy, thereby effectively utilizing part of the pressure potential energy, causing a pressure drop in the liquid. The liquid leaving the hydraulic generator unit enters the second liquid storage tank, and the compressed air with a lower pressure in the second liquid storage tank is driven to the air turbine generator unit for power generation. Thus, all the energy stored in the high-pressure compressed air can be fully utilized, avoiding the use of a pressure reducing valve to consume part of the pressure energy, thereby improving the energy utilization efficiency.

[0018] The compressed air energy storage system described in the present invention can be used in working conditions where the pressure of the air stored underground is higher than the maximum operating pressure of the air turbine generator set. Therefore, the construction site selection range of the compressed air energy storage system can be greatly expanded.

[0019] The present invention enables the compressed air to enter the second liquid storage tank and press the liquid therein into the hydraulic generator set, and the liquid leaving the hydraulic generator set to enter the first liquid storage tank and press the air therein into the air turbine generator set. This enables the liquid to reciprocate in the first liquid storage tank and the second liquid storage tank, thereby achieving power generation using a large amount of compressed air with a small amount of water. By exchanging liquid in the two liquid storage tanks, the use of a huge high-pressure liquid storage tank can be avoided.

[0020] The present invention includes a heat storage device with a heat storage fluid inside, and the heat storage fluid can flow from the heat storage device to the air compressor unit and absorb heat in the air compressor unit before flowing back to the heat storage device. The heat released by the air compressor unit can be absorbed by the heat storage fluid, and the heat can be used for other equipment to be heated, thereby improving energy utilization.

[0021] The present invention enables the heat storage fluid to flow from the heat storage device to the air turbine generator set and release heat therein, and then flow back to the heat storage device. The heat storage fluid can release heat to heat the air turbine generator set, thereby effectively improving the power generation efficiency of the air turbine generator set while improving energy utilization efficiency and avoiding heat waste.

[0022] The present invention is connected to the main gas inflow pipeline through an underground gas storage facility group, and the main gas inflow pipeline is respectively connected to the first liquid storage tank and the second liquid storage tank through two branch gas inflow pipelines, and the two branch gas inflow pipelines are respectively provided with a first gas valve and a second gas valve. By controlling the opening and closing of the first gas valve or the second gas valve, the compressed gas released by the underground gas storage facility group can be controlled to flow into one of the first liquid storage tank or the second liquid storage tank, so that the liquid can reciprocate in the first liquid storage tank and the second liquid storage tank, so that a large amount of compressed air can be used for power generation with a small amount of water. By exchanging liquid in the two liquid storage tanks, the use of a huge high-pressure liquid storage tank can be avoided, thereby improving the compatibility of equipment.

[0023] The present invention includes a main gas outflow pipe and two branch gas outflow pipes, and the first liquid storage tank and the second liquid storage tank are respectively connected to the main gas outflow pipe through the two branch gas outflow pipes, the two branch gas outflow pipes are respectively provided with a third gas valve and a fourth gas valve, and the main gas outflow pipe is connected to the air turbine generator set, so that the interiors of the first liquid storage tank and the second liquid storage tank are both connected to the air turbine generator set, and by controlling the opening and closing of the third gas valve and the fourth gas valve, the gas inside the first liquid storage tank or the second liquid storage tank can be controlled to flow to the air turbine generator set under the drive of the liquid to generate electricity.

[0024] The present invention includes a first liquid flow pipeline and a second liquid flow pipeline, and the first liquid storage tank and the second liquid storage tank are connected to the liquid input end of the hydraulic generator through the first liquid flow pipeline and the second liquid flow pipeline respectively, and the first liquid flow pipeline and the second liquid flow pipeline are respectively provided with a first liquid valve and a second liquid valve. By controlling the opening and closing of the first liquid valve and the second liquid valve, the liquid in the first liquid storage tank or the second liquid storage tank can be controlled to flow to the hydraulic generator to generate electricity.

[0025] The present invention includes a first liquid flow pipeline and a second liquid flow pipeline, and the first liquid storage tank and the second liquid storage tank are connected to the liquid input end of the hydraulic generator through the first liquid flow pipeline and the second liquid flow pipeline respectively, and the first liquid flow pipeline and the second liquid flow pipeline are respectively provided with a first liquid valve and a second liquid valve. By controlling the opening and closing of the first liquid valve and the second liquid valve, the liquid in the first liquid storage tank or the second liquid storage tank can be controlled to flow to the hydraulic generator to generate electricity.

[0026] The compressed air energy storage system described in the present invention also includes a control device (not shown in the figure), which is electrically connected to the first liquid valve, the second liquid valve, the third liquid valve, the fourth liquid valve, the first gas valve, the second gas valve, the third gas valve and the fourth gas valve, so that the opening and closing of each valve can be controlled according to the set strategy to improve the control efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The schematic diagram schematically shows the overall structure of the compressed air energy storage system according to the present invention.

[0028] In the present application, all drawings are schematic drawings, which are only used to illustrate the principles of the present invention and are not drawn according to the actual scale. DETAILED DESCRIPTION

[0029] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] In the description of the present invention, it is necessary to understand that the orientations or positional relationships indicated by the terms “inside”, “upper”, etc. are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0031] In the present invention, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral or connected connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] like Figure 1 As shown, the compressed air energy storage system 100 of the present invention includes an air compressor unit 1 for compressing air, an underground gas storage facility unit 2 for storing compressed air, a first liquid storage tank 4, a hydraulic generator unit 6, a second liquid storage tank 5 and an air turbine generator unit 7, wherein the air compressor unit 1 can use electric energy or other energy sources to compress the air in the environment so that the compressed air has a higher pressure, the hydraulic generator unit 6 can generate electricity under the drive of liquid fluid, and the air turbine generator unit 7 can generate electricity under the drive of compressed air flowing into it, and the compressed air in the underground gas storage facility unit 2 enters the first liquid storage tank 4, and presses the liquid in the first liquid storage tank 4 into the hydraulic generator unit 6, and the liquid then drives the hydraulic generator unit 6, so that the hydraulic generator unit 6 generates electricity. The liquid leaving the hydraulic generator unit 6 enters the second liquid storage tank 5, and the second liquid storage tank 5 is filled with air. The liquid enters the second liquid storage tank 5, and the air therein is pressed into the air turbine generator unit 7, so that the air turbine generator unit 7 generates electricity under the drive of compressed air. Optionally, the liquid inside the first liquid storage tank 4 is water. Optionally, the hydraulic generator set 6 is a hydroelectric generator set with two-stage series-connected Pelton turbines, an inlet pressure of 45 MPa, and an outlet pressure of 30 MPa. The air turbine generator set 7 can use a multi-stage air turbine, an inlet pressure of 30 MPa, and an exhaust pressure of normal pressure.

[0033] It should be noted that the underground gas storage facility group 2 has a certain connected pore volume or continuous space volume, and has good sealing performance, and can store air within a certain pressure range. In the present invention, the underground gas storage facility group 2 can store high-pressure air compressed by the air compressor group 1, and can release compressed air when needed. Optionally, depleted oil and gas reservoirs, permeable formations, underground caves, etc. can all be part of the underground gas storage facility group 2. For example, it can be selected to be located in anticline structure, with dense mudstone caprock, no faults passing through, porosity greater than 20%, and permeability greater than 0.5×10 -12 m 2 The formation is used as an underground high-pressure gas storage space, and the original formation pore pressure of the formation is set to 45MPa. The air compressor unit 1 can use a multi-stage compressor to compress the ambient air to 45MPa and inject it into the formation.

[0034] It should be noted that the first liquid storage tank 4 and the second liquid storage tank 5 can both contain a certain amount of liquid and withstand a relatively high pressure. The pressure that the first liquid storage tank 4 and the second liquid storage tank 5 can withstand is not less than the pressure of the compressed air released by the underground gas storage facility group 2. The first liquid storage tank 4 and the second liquid storage tank 5 have approximately the same volume. The first liquid storage tank 4 and the second liquid storage tank 5 can both have a volume of 500m 3 , underground water tank with pressure resistance of 50MPa.

[0035] The compressed air flowing from the underground gas storage facility group 2 into the first liquid storage tank 4 continuously drives the liquid in the first liquid storage tank 4 to flow through the hydraulic generator group 6 and to the second liquid storage tank 5 until the second liquid storage tank 5 is nearly full. Since the hydraulic generator group 6 converts part of the pressure potential energy of the liquid into electrical energy during the flow through the hydraulic generator group 6, part of the pressure potential energy is effectively utilized, resulting in a pressure drop in the liquid, which can make the air pressure above the liquid in the second liquid storage tank 5 lower than the air pressure above the liquid in the first liquid storage tank 4, and also lower than the pressure of the compressed air released by the underground gas storage facility group 2.

[0036] The present invention includes an air compressor unit 1 for compressing air, an underground gas storage facility unit 2 for storing compressed air, a first liquid storage tank 4, a hydraulic generator unit 6, a second liquid storage tank 5 and an air turbine generator unit 7. The compressed air in the underground gas storage facility unit 2 enters the first liquid storage tank 4 and presses the liquid therein into the hydraulic generator unit 6, so that the hydraulic generator unit 6 generates electricity. The liquid leaving the hydraulic generator unit 6 enters the second liquid storage tank 5 and presses the air therein into the air turbine generator unit 7, so that the air turbine generator unit 7 generates electricity. The high-pressure compressed air can be used to continuously drive the liquid in the first liquid storage tank 4 to flow through the hydraulic generator unit 6. The hydraulic generator unit 6 can convert part of the pressure potential energy of the liquid into electrical energy, thereby effectively utilizing part of the pressure potential energy, causing a pressure drop in the liquid. The liquid leaving the hydraulic generator unit 6 enters the second liquid storage tank 5. By driving the compressed air with a lower pressure in the second liquid storage tank 5 to the air turbine generator unit 7 for power generation, all the energy stored in the high-pressure compressed air can be fully utilized, avoiding the use of a pressure reducing valve to consume part of the pressure energy, thereby improving the energy utilization efficiency.

[0037] The compressed air energy storage system 100 described in the present invention can be used in working conditions where the pressure of the air stored underground is higher than the maximum operating pressure (about 35 MPa) of the air turbine generator set 7. Therefore, the construction site selection range of the compressed air energy storage system can be greatly expanded.

[0038] In one or more embodiments, the compressed air in the underground gas storage facility group 2 can also enter the second liquid storage tank 5 and press the liquid therein into the hydraulic generator set 6 so that the hydraulic generator set 6 generates electricity. The liquid leaving the hydraulic generator set 6 enters the first liquid storage tank 5 and presses the air therein into the air turbine generator set 7 so that the air turbine generator set 7 generates electricity.

[0039] The compressed air flowing into the first liquid storage tank 4 from the underground gas storage facility group 2 continuously drives the liquid in the first liquid storage tank 4 to flow through the hydraulic generator set 6 and flow to the second liquid storage tank 5 until the second liquid storage tank 5 is nearly full. The compressed air in the underground gas storage facility group 2 can also be allowed to enter the second liquid storage tank 5 through the valve group, and the liquid therein is pressed into the hydraulic generator set 6, and the liquid leaving the hydraulic generator set 6 enters the first liquid storage tank 5, thereby driving the liquid in the nearly full second liquid storage tank 5 to the first liquid storage tank 4 again, and pressing the air in the first liquid storage tank 4 into the air turbine generator set 7, so that the air turbine generator set 7 generates electricity.

[0040] Since the amount of air stored in the underground gas storage facility group 2 often reaches 107Nm 3Level, if a single liquid storage tank is used, the volume of the water tank needs to reach the same order of magnitude, which makes it difficult to achieve. The present invention allows compressed air to enter the second liquid storage tank 5 and press the liquid therein into the hydraulic generator set 6, and the liquid leaving the hydraulic generator set 6 enters the first liquid storage tank 5 and presses the air therein into the air turbine generator set 7. The liquid can be made to reciprocate in the first liquid storage tank 4 and the second liquid storage tank 5, so that a large amount of compressed air can be used for power generation with a small amount of water. By exchanging the liquid in the two liquid storage tanks, the use of a huge high-pressure liquid storage tank can be avoided.

[0041] In one or more embodiments, the first liquid storage tank 4 and the second liquid storage tank 5 both have an oil layer that is insoluble in water above the internal liquid layer, which can prevent large amounts of liquid in the first liquid storage tank 4 and the second liquid storage tank 5 from evaporating, thereby avoiding affecting the operation of the air turbine generator set 7.

[0042] In one or more embodiments, the compressed air energy storage system 100 of the present invention further includes a heat storage device 3 having a heat storage fluid therein, and the heat storage fluid can flow from the heat storage device 3 to the air compressor unit 1 and absorb heat in the air compressor unit 1 before flowing back to the heat storage device 3. The heat storage fluid has a high specific heat capacity. The heat storage fluid of the heat storage device 3 can be heat transfer oil, the main component of which is alkylbenzene, and the heat storage temperature thereof can reach 300°C.

[0043] Specifically, when the heat storage fluid stored in the heat storage device 3 is in a low-temperature state, the heat storage fluid can flow out of the heat storage device 3 and flow through the air compressor unit 1 through the pipeline. In this process, the heat storage fluid absorbs the heat released by the air compressor unit 1 during the air compression process and becomes a heat storage fluid in a high-temperature state, and then flows back to the heat storage device 3 through the pipeline.

[0044] The present invention includes a heat storage device 3 with a heat storage fluid inside, and the heat storage fluid can flow from the heat storage device 3 to the air compressor unit 1 and absorb heat in the air compressor unit 1, and then flow back to the heat storage device 3. The heat released by the air compressor unit 1 can be absorbed by the heat storage fluid, and the heat can be used for other equipment to be heated, thereby improving energy utilization.

[0045] In one or more embodiments, the heat storage fluid can also flow from the heat storage device 3 to the air turbine generator set 7 and release heat therein, and then flow back to the heat storage device 3 .

[0046] Specifically, when the heat storage fluid stored in the heat storage device 3 is in a high temperature state, the heat storage fluid can flow out of the heat storage device 3 and flow through the air turbine generator set 7. In this process, the heat storage fluid releases heat to heat the air turbine generator set 7, thereby improving the power generation efficiency of the air turbine generator set 7, and then becomes a heat storage fluid in a low temperature state, and then flows back to the heat storage device 3 through the pipeline.

[0047] The present invention enables the heat storage fluid to flow from the heat storage device 3 to the air turbine generator set 7 and release heat therein, and then flow back to the heat storage device 3. The heat storage fluid can release heat to heat the air turbine generator set 7, thereby effectively improving the power generation efficiency of the air turbine generator set 7 while improving energy utilization efficiency and avoiding heat waste.

[0048] In one or more embodiments, the compressed air energy storage system 100 described in the present invention includes a main gas inflow pipeline A and two branch gas inflow pipelines a. The underground gas storage facility group 2 is connected to the main gas inflow pipeline A. The main gas inflow pipeline A is respectively connected to the first liquid storage tank 4 and the second liquid storage tank 5 through the two branch gas inflow pipelines a. The two branch gas inflow pipelines a are respectively provided with a first gas valve 8 and a second gas valve 11.

[0049] The present invention is connected to the main gas inflow pipeline A through the underground gas storage facility group 2, and the main gas inflow pipeline A is respectively connected to the first liquid storage tank 4 and the second liquid storage tank 5 through two branch gas inflow pipelines a, and the two branch gas inflow pipelines a are respectively provided with a first gas valve 8 and a second gas valve 11. By controlling the opening and closing of the first gas valve 8 or the second gas valve 11, the compressed gas released by the underground gas storage facility group 2 can be controlled to flow into one of the first liquid storage tank 4 or the second liquid storage tank 5, so that the liquid can reciprocate in the first liquid storage tank 4 and the second liquid storage tank 5, so that a large amount of compressed air can be used for power generation with a small amount of water. By exchanging liquid in the two liquid storage tanks, the use of a huge high-pressure liquid storage tank can be avoided, thereby improving the compatibility of equipment.

[0050] In one or more embodiments, the compressed air energy storage system 100 described in the present invention also includes a main gas outflow pipe B and two branch gas outflow pipes b. The first liquid storage tank 4 and the second liquid storage tank 5 are respectively connected to the main gas outflow pipe B through the two branch gas outflow pipes b. The two branch gas outflow pipes b are respectively provided with a third gas valve 9 and a fourth gas valve 10. The main gas outflow pipe B is connected to the air turbine generator set 7.

[0051] The present invention includes a main gas outflow pipe B and two branch gas outflow pipes b, and the first liquid storage tank 4 and the second liquid storage tank 5 are respectively connected to the main gas outflow pipe B through the two branch gas outflow pipes b, the two branch gas outflow pipes b are respectively provided with a third air valve 9 and a fourth air valve 11, and the main gas outflow pipe B is connected to the air turbine generator set 7, so that the interiors of the first liquid storage tank 4 and the second liquid storage tank 5 are connected to the air turbine generator set 7, and by controlling the opening and closing of the third air valve 9 and the fourth air valve 11, the gas inside the first liquid storage tank 4 or the second liquid storage tank 5 can be controlled to flow to the air turbine generator set 7 under the drive of the liquid to generate electricity.

[0052] In one or more embodiments, the compressed air energy storage system 100 described in the present invention also includes a first liquid flow pipeline c and a second liquid flow pipeline d, the first liquid storage tank 4 and the second liquid storage tank 5 are respectively connected to the liquid input end of the hydraulic generator 6 through the first liquid flow pipeline c and the second liquid flow pipeline d, and the first liquid flow pipeline c and the second liquid flow pipeline d are respectively provided with a first liquid valve 12 and a second liquid valve 13.

[0053] The present invention includes a first liquid flow pipeline c and a second liquid flow pipeline d, and the first liquid storage tank 4 and the second liquid storage tank 5 are connected to the liquid input end of the hydraulic generator 6 through the first liquid flow pipeline c and the second liquid flow pipeline d respectively, and the first liquid flow pipeline c and the second liquid flow pipeline d are respectively provided with a first liquid valve 12 and a second liquid valve 13. By controlling the opening and closing of the first liquid valve 12 and the second liquid valve 13, the liquid in the first liquid storage tank 4 or the second liquid storage tank 5 can be controlled to flow to the hydraulic generator 6 to generate electricity.

[0054] In one or more embodiments, the compressed air energy storage system 100 described in the present invention also includes a third liquid flow pipeline e and a fourth liquid flow pipeline f. The first liquid storage tank 4 and the second liquid storage tank 5 are respectively connected to the liquid output end of the hydraulic generator 6 through the third liquid flow pipeline e and the fourth liquid flow pipeline f. The third liquid flow pipeline e and the fourth liquid flow pipeline f are respectively provided with a third liquid valve 14 and a fourth liquid valve 15.

[0055] The present invention includes a third liquid flow pipeline e and a fourth liquid flow pipeline f, and the first liquid storage tank 4 and the second liquid storage tank 5 are connected to the liquid output end of the hydraulic generator 6 through the third liquid flow pipeline e and the fourth liquid flow pipeline f respectively, and the third liquid flow pipeline e and the fourth liquid flow pipeline f are respectively provided with a third liquid valve 14 and a fourth liquid valve 15. By controlling the opening and closing of the third liquid valve 14 and the fourth liquid valve 15, the liquid in the first liquid storage tank 4 or the second liquid storage tank 5 can be controlled to flow to the hydraulic generator 6 and flow out to the second liquid storage tank 5 or the first liquid storage tank 4 to generate electricity.

[0056] In one or more embodiments, the compressed air energy storage system 100 described in the present invention also includes a control device (not shown in the figure), and the control device is electrically connected to the first liquid valve 12, the second liquid valve 13, the third liquid valve 14, the fourth liquid valve 15, the first gas valve 8, the second gas valve 11, the third gas valve 9 and the fourth gas valve 10.

[0057] The present invention is electrically connected to the first liquid valve 12, the second liquid valve 13, the third liquid valve 14, the fourth liquid valve 15, the first gas valve 8, the second gas valve 11, the third gas valve 9 and the fourth gas valve 10 through the control device, and can remotely control the opening and closing of each valve according to the set strategy, thereby improving the efficiency of controlling the opening and closing of the valves.

[0058] Specifically, the working process of the compressed air energy storage system 100 described in the present invention includes an energy storage process and a power generation process.

[0059] Energy storage process: When the pressure of the compressed air in the underground gas storage facility group 2 is lower than its maximum allowable operating pressure, and the temperature of the heat storage fluid in the heat storage device 3 is lower than its maximum allowable operating temperature, the compressed air energy storage system 100 has spare energy storage capacity and the energy storage process can be performed. When performing the energy storage process, the air compressor group 1 compresses the air into high-pressure compressed air and transports it into the underground gas storage facility group 2 for storage. At the same time, the heat storage fluid flows out of the heat storage device 3, flows through the air compressor group 1, absorbs the heat dissipated by the air compressor group 1 during the air compression process and the heat generated by the air due to compression, and then flows back to the heat storage device 3.

[0060] It should be noted that the gas storage mechanism has an upper and lower operating pressure limit. When the pressure is higher than the lower pressure limit, it means that there is surplus energy for power generation. The heat storage mechanism is used to heat the expanded gas. When the temperature is higher than the minimum temperature, it means that there is surplus heat that can be used for heating.

[0061] Power generation process: When the pressure of the compressed air in the underground gas storage facility group 2 is higher than its minimum allowable operating pressure, and the temperature of the heat storage fluid in the heat storage device 3 is higher than its minimum allowable operating temperature, the compressed air energy storage system 100 has stored energy and can perform the power generation process. The power generation process of the compressed air energy storage system 100 described in the present invention has two operating conditions, and the two operating conditions can be switched to each other.

[0062] Working condition 1: the control device controls the first gas valve 8 to open and the second gas valve 11 to close, the third gas valve 9 to close and the fourth gas valve 10 to open, the first liquid valve 12 and the fourth liquid valve 15 to open, and the second liquid valve 13 and the third liquid valve 14 to close.

[0063] Under this working condition: the compressed air flowing out of the underground gas storage facility group 2 enters the first liquid storage tank 4 through the first air valve 8, and drives the liquid in the first liquid storage tank 4 to flow into the hydraulic generator set 6 through the first liquid valve 12, so that the hydraulic generator set 6 generates electricity under the drive of the liquid, and the liquid then flows into the second liquid storage tank 5 through the fourth liquid valve 15, and drives the air inside the second liquid storage tank 5 to flow into the air turbine generator set 7 through the fourth air valve 10, so that the air turbine generator set 7 generates electricity under the drive of the compressed air.

[0064] The compressed air flowing into the first liquid storage tank 4 from the underground gas storage facility group 2 continuously drives the liquid to flow from the first liquid storage tank 4 through the hydraulic generator set 6 and to the second liquid storage tank 5 until the second liquid storage tank 5 is almost full. During this process, since the hydraulic generator set 6 consumes part of the pressure potential energy, a pressure drop occurs, so that the air pressure inside the second liquid storage tank 5 is lower than the air pressure inside the first liquid storage tank 4, and also lower than the pressure of the compressed air released by the underground high-pressure gas storage facility 2.

[0065] Working condition 2: the control device controls the second gas valve 11 to open and the first gas valve 8 to close, the third gas valve 9 to open and the fourth gas valve 10 to close, the first liquid valve 12 and the fourth liquid valve 15 to close, and the second liquid valve 13 and the third liquid valve 14 to open.

[0066] Under this working condition: the compressed air flowing out of the underground gas storage facility group 2 enters the second liquid storage tank 5 through the second air valve 11, and drives the liquid in the second liquid storage tank 5 to flow into the hydraulic generator set 6 through the second liquid valve 13, so that the hydraulic generator set 6 generates electricity under the drive of the liquid, and the liquid then flows into the first liquid storage tank 4 through the third liquid valve 14, and drives the air inside the first liquid storage tank 4 to flow into the air turbine generator set 7 through the third air valve 9, so that the air turbine generator set 7 generates electricity under the drive of the compressed air.

[0067] During this process, the compressed air released from the underground gas storage facility group 2 first drives the liquid in the second liquid storage tank 5 to flow through the hydraulic generator set 6 to generate electricity, and then enters the first liquid storage tank 4, and drives the compressed air inside the first liquid storage tank 4 to enter the air turbine generator set 7 to generate electricity, until the water level in the first liquid storage tank 4 approaches the upper limit, and then switches to operating condition one.

[0068] Although the present invention has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A compressed air energy storage system, comprising an air compressor unit for compressing air, an underground gas storage facility unit for storing compressed air, a first liquid storage tank, a hydraulic generator unit, a second liquid storage tank and an air turbine generator unit, wherein the compressed air in the underground gas storage facility unit enters the first liquid storage tank, and the liquid therein is pressed into the hydraulic generator unit so that the hydraulic generator unit generates electricity, and the liquid leaving the hydraulic generator unit enters the second liquid storage tank, and the air therein is pressed into the air turbine generator unit so that the air turbine generator unit generates electricity.

2. The compressed air energy storage system according to claim 1, characterized in that: The compressed air in the underground gas storage facility group can also enter the second liquid storage tank and press the liquid therein into the hydraulic generator set so that the hydraulic generator set generates electricity. The liquid leaving the hydraulic generator set enters the first liquid storage tank and presses the air therein into the air turbine generator set so that the air turbine generator set generates electricity.

3. The compressed air energy storage system according to claim 2, characterized in that: The first liquid storage tank and the second liquid storage tank both have an oil layer above the liquid layer inside.

4. The compressed air energy storage system according to claim 2, characterized in that: It also includes a heat storage device with a heat storage fluid inside. The heat storage fluid can flow from the heat storage device to the air compressor unit and absorb heat therein, and then flow back to the heat storage device.

5. The compressed air energy storage system according to claim 4, characterized in that: The heat storage fluid can also flow from the heat storage device to the air turbine generator set and, after releasing heat therein, flow back to the heat storage device.

6. The compressed air energy storage system according to claim 2, characterized in that: It includes a main gas inflow pipeline and two branch gas inflow pipelines. The underground gas storage facility group is connected to the main gas inflow pipeline. The main gas inflow pipeline is respectively connected to the first liquid storage tank and the second liquid storage tank through the two branch gas inflow pipelines. The two branch gas inflow pipelines are respectively provided with a first gas valve and a second gas valve.

7. The compressed air energy storage system according to claim 6, characterized in that: It also includes a main gas outflow pipe and two branch gas outflow pipes. The first liquid storage tank and the second liquid storage tank are connected to the main gas outflow pipe through the two branch gas outflow pipes respectively. The two branch gas outflow pipes are respectively provided with a third gas valve and a fourth gas valve. The main gas outflow pipe is connected to the air turbine generator set.

8. The compressed air energy storage system according to claim 7, characterized in that: It also includes a first liquid flow pipeline and a second liquid flow pipeline. The first liquid storage tank and the second liquid storage tank are connected to the liquid input end of the hydraulic generator through the first liquid flow pipeline and the second liquid flow pipeline respectively. The first liquid flow pipeline and the second liquid flow pipeline are respectively provided with a first liquid valve and a second liquid valve.

9. The compressed air energy storage system according to claim 8, characterized in that: It also includes a third liquid flow pipeline and a fourth liquid flow pipeline. The first liquid storage tank and the second liquid storage tank are connected to the liquid output end of the hydraulic generator through the third liquid flow pipeline and the fourth liquid flow pipeline respectively. The third liquid flow pipeline and the fourth liquid flow pipeline are respectively provided with a third liquid valve and a fourth liquid valve.

10. The compressed air energy storage system according to claim 9, characterized in that: It also includes a control device, which is electrically connected to the first liquid valve, the second liquid valve, the third liquid valve, the fourth liquid valve, the first gas valve, the second gas valve, the third gas valve and the fourth gas valve.

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