Multi-stage compressed air energy storage system and power station

Abstract

The present invention relates to the technical field of compressed air energy storage, and discloses a multi-stage compressed air energy storage system and a power station, wherein the multi-stage compressed air energy storage system comprises: a plurality of energy storage devices and a plurality of energy release devices; each energy storage device comprises: a compressor and a gas storage structure, the compressor is connected to an input power source; the gas storage structure is connected to the compressor through a first pipeline; a plurality of compressors are sequentially connected in series through a second pipeline; a plurality of gas storage structures are sequentially connected in series through a third pipeline; each energy release device comprises: an expander, which is connected to the gas storage structure through a fourth pipeline; the expander is connected to a generator and drives the generator to generate electricity; a plurality of expanders are sequentially connected in series through a fifth pipeline. Each compressor of the present invention is respectively connected to a gas storage structure, and a plurality of compressors, gas storage structures and expanders are respectively connected in series in sequence, which can quickly switch different compressor combinations, thereby improving the energy storage efficiency and variable operating condition adjustment capability of the multi-stage compressed air energy storage system.

Description

Technical Field

[0001] The present invention relates to the technical field of compressed air energy storage, and in particular to a multi-stage compressed air energy storage system and a power station. Background Art

[0002] Compressed air energy storage is a physical energy storage technology that can be applied on a large scale. It refers to a storage method that uses electrical energy to compress air in compressors during the low load period of the power grid, and releases compressed air to drive expanders to generate electricity during the peak load period of the power grid. It has a positive role in promoting the high-proportion access and consumption of large-scale centralized power stations.

[0003] Because the power load input during the off-peak period of the power grid is different in different working scenarios, the power that can be supplied to the compressor to compress air is also different, resulting in the compressed air energy storage system being unable to be used in working scenarios with different input power sources. At present, some compressed air energy storage systems use a graded compression method, and high and low pressure air storage chambers are set up accordingly. Depending on the load strength of the input power source, different combinations of compressors are selected, such as the low-pressure unit running alone, the high-pressure unit running alone, or all units running, etc., to adapt to input power sources with different load intensities, so as to increase the range of use scenarios of the compressed air energy storage system.

[0004] The defect of this structure is that in the application scenarios of renewable energy power stations such as wind power and photovoltaic power, the load of its input power supply has large fluctuations due to factors such as uneven wind force or uneven light. The existing compressed air energy storage system switches between different combinations of compressors at a slow speed, resulting in poor use effect. Summary of the invention

[0005] In view of this, the present invention provides a multi-stage compressed air energy storage system and a power station to solve the problem that the existing compressed air energy storage system cannot quickly switch the compressor combination and has poor use effect.

[0006] In a first aspect, the present invention provides a multi-stage compressed air energy storage system, comprising: a plurality of energy storage devices and a plurality of energy release devices; each energy storage device comprises: a compressor, suitable for being connected to an input power source and being driven by the input power source; a gas storage structure, connected to the compressor through a first pipeline; a first switch valve is provided on the first pipeline; a plurality of compressors are connected in series through a second pipeline in turn, and a second switch valve is provided on the second pipeline; a plurality of gas storage structures are connected in series through a third pipeline in turn, and a third switch valve is provided on the third pipeline; each energy release device comprises: an expander, connected to the gas storage structure through a fourth pipeline; a fourth switch valve is provided on the fourth pipeline; the expander is suitable for being connected to a generator and driving the generator to generate electricity; a plurality of expanders are connected in series through a fifth pipeline in turn, and a fifth switch valve is provided on the fifth pipeline.

[0007] Beneficial effects: Each compressor of the present invention is respectively connected to a gas storage structure and an expander, and each energy storage device can be used alone with a corresponding energy release device to form multiple independent compressed air energy storage structures, which do not affect each other, are stable to use, and have a wide range of applicable working conditions. According to the specific application working condition scenario, different compressor combinations can be selected, which has good flexibility, so that the supply and demand balance between the user side, the multi-stage compressed air energy storage system and the power grid where the generator is located can be met. Multiple compressors, multiple expanders and multiple gas storage structures are connected in series in sequence to form multi-stage hierarchical regulation. Each energy storage device and each energy release device are connected to each other. By opening and closing the valves of each pipeline, different compressor combinations can be quickly switched to meet the use conditions of the input power supply with more frequent fluctuations, thereby improving the energy storage efficiency of the multi-stage compressed air energy storage system. Compared with the traditional hierarchical compressed air energy storage system that is easily restricted by the adjustment of the operating condition scenario, the embodiment of the present invention can also smooth the negative impact of the volatility of the input power supply, cause less damage to the components of the multi-stage compressed air energy storage system, and be safer to use, that is, it has a better variable working condition adjustment capability.

[0008] In an optional embodiment, the air pressure in the multiple compressors increases successively in the order in which the multiple compressors are connected in series, and the air pressure in the multiple air storage structures increases successively corresponding to the order in which the multiple compressors are connected in series.

[0009] Beneficial effects: The present invention forms multiple levels of energy storage and energy release by setting up multiple compressors and air storage structures with different air pressures. Then, according to the strength of the actual input power supply, a corresponding combination of one or more energy storage devices and energy release devices can be selected to improve the energy storage efficiency of the multi-stage compressed air energy storage system.

[0010] In an optional embodiment, the expander is connected to another adjacent low-pressure gas storage structure through a sixth pipeline, and a sixth switch valve is provided on the sixth pipeline.

[0011] Beneficial effect: When the load of the input power supply is small and the gas reserve in the gas storage structure is insufficient, the sixth switch valve can be opened to transport the sub-high pressure gas generated by the expander to another adjacent low-pressure gas storage structure through the sixth pipeline to replenish the gas reserve in the gas storage structure, improve energy utilization and save energy consumption.

[0012] In an optional implementation, the fourth pipeline is connected to the third pipeline, and the connecting point between the fourth pipeline and the third pipeline is located between the third switch valve and the gas storage structure.

[0013] Beneficial effect: the fourth pipeline is connected to the third pipeline, and the connecting point between the fourth pipeline and the third pipeline is located between the third switch valve and the gas storage structure, which can simplify the pipeline connection and reduce the use cost.

[0014] In an optional embodiment, the first pipeline is connected to the second pipeline; the first pipeline is also provided with a first one-way valve, and the first one-way valve is located between the first heat exchange part and the connection between the first pipeline and the second pipeline.

[0015] Beneficial effects: The first pipeline is connected to the second pipeline, which can further simplify pipeline connection and reduce use costs. The first one-way valve can effectively prevent gas from flowing back from the first pipeline to the compressor.

[0016] In an optional implementation, the first switch valve and the fourth switch valve are both two-way valves.

[0017] Beneficial effects: The first switch valve is a two-way valve, and the gas in the gas storage structure can also enter the next higher pressure compressor through the first pipeline and the second pipeline, which is conducive to improving the switching speed of different combinations of compressors. Similarly, the fourth switch valve is a two-way valve, and the gas of the expander can enter the next lower pressure gas storage structure through the fourth pipeline, which improves the switching speed of different combinations of compressors, thereby improving the working efficiency of the multi-stage compressed air energy storage system.

[0018] In an optional embodiment, the energy storage device and the energy release device are connected one-to-one, and each energy storage device and the corresponding energy release device can operate independently and drive at least one compressor based on the strength of the input power supply.

[0019] Beneficial effects: The present invention can select one or more compressors and their corresponding gas storage structures and expanders to store and release compressed air energy according to the strength of the input power supply, effectively meeting the use requirements of different input power supplies in different scenarios.

[0020] In an optional embodiment, a heat exchanger is further included, and the heat exchanger is arranged on the first pipeline to absorb the heat released by the compressor.

[0021] Beneficial effect: The present invention can recover the waste heat generated when the compressor compresses gas by arranging a heat exchanger, thereby improving energy utilization and saving energy consumption.

[0022] In an optional embodiment, the heat exchanger includes a first heat exchange part and a second heat exchange part that are connected to each other. The first heat exchange part is arranged in the first pipeline, between the compressor and the first switch valve, and is used to absorb the heat released by the compressor; the second heat exchange part is arranged in the fourth pipeline, between the fourth switch valve and the expander, and is used to heat the gas in the fourth pipeline.

[0023] Beneficial effect: The heat exchanger recovers the waste heat generated when the compressor compresses the gas through the first heat exchange part, and heats the gas in the fourth pipeline with the recovered heat through the second heat exchange part. The gas then enters the expander, which is beneficial for the expander to drive the generator to generate electricity.

[0024] In an optional embodiment, the heat exchanger further includes a third heat exchange part, which is communicated with the first heat exchange part and is arranged in the fifth pipeline.

[0025] Beneficial effect: The heat recovered by the first heat exchange part of the heat exchanger can also heat the gas in the fifth pipeline through the third heat exchange part. After the gas is heated, it enters the lower-pressure expander from the higher-pressure expander, which is beneficial for the lower-pressure expander to drive the generator to generate electricity, and further improves energy utilization.

[0026] In an optional embodiment, the energy storage device further includes an air inlet pipe, the compressor includes an air inlet port, and the air inlet port is connected to the air inlet pipe; the energy release device includes an exhaust pipe, the expander includes an exhaust port, and the exhaust port is connected to the exhaust pipe.

[0027] Beneficial effects: The compressor can access the gas in the intake pipe from the air inlet, and store it in the gas storage structure after compression. The gas in the gas storage structure then enters the expander, drives the engine to generate electricity, and finally is discharged from the outlet through the exhaust pipe. Each compressor is provided with an air inlet, and each expander is provided with an air outlet, so that each energy storage device and each energy release device can operate independently.

[0028] In an optional embodiment, the compressor includes at least one of a piston compressor, a rotary compressor, a centrifugal compressor, an axial compressor, and a hybrid compressor.

[0029] Beneficial effects: The present invention can directly adopt various existing compressors, has low use cost, and is conducive to promotion.

[0030] In an optional embodiment, the expander includes at least one of a piston expander, a rotary expander and a turbine expander.

[0031] Beneficial effect: The present invention can directly adopt various existing expanders, further reducing the use cost.

[0032] In an optional embodiment, the gas storage structure includes at least one of a gas storage tank, an underground salt cavern, an artificial underground chamber, a pipeline steel bundle gas storage reservoir, and an air bag.

[0033] Beneficial effects: The gas storage structure of the present invention can be applied to a variety of working scenarios to increase the scope of use of the multi-stage compressed air energy storage system.

[0034] In a second aspect, the present invention also provides a power station, comprising: multiple input power sources; multiple generators; the above-mentioned multi-stage compressed air energy storage system, the input power source is connected to the compressor in the multi-stage compressed air energy storage system, for driving the compressor to compress air; the generator is connected to the expander, for being driven by the expander and generating electricity.

[0035] Beneficial effects: Because the power station includes a multi-stage compressed air energy storage system, it has the same effect as the multi-stage compressed air energy storage system, that is, it can form multiple independent compressed air energy storage structures that do not affect each other and are stable to use. It can also form multi-stage graded regulation, which is conducive to rapid switching of different compressor combinations and can meet the use conditions of input power with more frequent fluctuations, thereby improving the use effect of the multi-stage compressed air energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 A schematic structural diagram of a multi-stage compressed air energy storage system according to an embodiment of the present invention;

[0038] Figure 2 A schematic diagram of the local structure of a multi-stage compressed air energy storage system in scene 1 according to an embodiment of the present invention;

[0039] Figure 3 A schematic diagram of the local structure of a multi-stage compressed air energy storage system in scenario 2 according to an embodiment of the present invention;

[0040] Figure 4 A schematic diagram of the local structure of a multi-stage compressed air energy storage system in scenario three according to an embodiment of the present invention;

[0041] Figure 5 Another partial structural schematic diagram of a multi-stage compressed air energy storage system in scenario three according to an embodiment of the present invention;

[0042] Figure 6 This is a schematic diagram of the local structure of a multi-stage compressed air energy storage system in scene four of the present invention.

[0043] Description of reference numerals:

[0044] 1. Compressor; 2. Gas storage structure; 3. First pipeline; 4. First switch valve; 5. Second pipeline; 6. Second switch valve; 7. Third pipeline; 8. Third switch valve; 9. Expander; 10. Fourth pipeline; 11. Fourth switch valve; 12. Fifth pipeline; 13. Sixth pipeline; 14. Sixth switch valve; 15. First heat exchange unit; 16. Second heat exchange unit; 17. Third heat exchange unit; 18. First non-return valve; 19. Inlet pipe; 20. Exhaust pipe; 21. Input power supply; 22. Generator. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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 those skilled in the art without creative work are within the scope of protection of the present invention.

[0046] In view of the problem that the existing compressed air energy storage system cannot quickly switch the compressor combination and has poor use effect, the embodiment of the present invention proposes that each compressor is respectively connected to an air storage structure and an expander, and multiple compressors, expanders and air storage structures are respectively connected in series in sequence to form multi-stage graded control, which can quickly switch different compressor combinations and improve the use effect of the multi-stage compressed air energy storage system.

[0047] Combine the following Figures 1 to 6 , describing an embodiment of the present invention.

[0048] According to an embodiment of the present invention, on the one hand, a multi-stage compressed air energy storage system is provided, which mainly includes: a plurality of energy storage devices and a plurality of energy release devices. Among them, each energy storage device mainly includes: a compressor 1 and a gas storage structure 2. The compressor 1 is suitable for being connected to an input power supply 21 and driven by the input power supply 21 to compress gas. The gas storage structure 2 is connected to the compressor 1 through a first pipeline 3, and is used to store the gas compressed by the first pipeline 3. A first switch valve 4 is provided on the first pipeline 3. A plurality of compressors 1 are connected in series through a second pipeline 5 in sequence. A second switch valve 6 is provided on the second pipeline 5. A plurality of gas storage structures 2 are connected in series through a third pipeline 7 in sequence, and a third switch valve 8 is provided on the third pipeline 7. Each energy release device includes: an expander 9. The expander 9 is connected to the gas storage structure 2 through a fourth pipeline 10. A fourth switch valve 11 is provided on the fourth pipeline 10. The expander 9 is suitable for being connected to a generator 22 and driving the generator 22 to generate electricity. A plurality of expanders 9 are connected in series through a fifth pipeline 12 in sequence, and a fifth switch valve (not shown in the figure) is provided on the fifth pipeline 12.

[0049] Each compressor 1 of the embodiment of the present invention is respectively connected to a gas storage structure 2 and an expander 9, and each energy storage device can be used alone with a corresponding energy release device to form a plurality of independent compressed air energy storage structures, which do not affect each other and are stable to use. According to the specific application scenario, different combinations of compressors 1 can be selected, which has good flexibility, so as to meet the supply and demand balance between the user side, the multi-stage compressed air energy storage system and the power grid where the generator 22 is located. Multiple compressors 1, multiple expanders 9 and multiple gas storage structures 2 are connected in series in sequence to form multi-stage graded regulation. Each energy storage device and each energy release device are connected to each other. By opening and closing the valves of each pipeline, different combinations of compressors 1 can be quickly switched to meet the use conditions where the input power supply 21 has a high frequency fluctuation, thereby improving the energy storage efficiency of the multi-stage compressed air energy storage system.

[0050] Compared with the traditional hierarchical compressed air energy storage system that is easily restricted by the operating condition scene adjustment, the embodiment of the present invention can smooth the negative impact of the volatility of the input power supply 21, cause less damage to the components of the multi-stage compressed air energy storage system, and is safer to use, that is, it has better variable condition adjustment capability. The gas storage structure 2 can also decouple the process of compressing gas and the process of expanding gas, and use renewable compressed gas to achieve the effect of stable output of electrical energy.

[0051] Specifically, the multi-stage compressed air energy storage system includes an energy storage state and an energy release state. In the energy storage state, one or more compressors 1 are selected to work according to the strength of the input power supply 21, and the input power supply 21 drives the compressor 1 to compress and pressurize the air. The pressurized gas enters the gas storage structure 2 through the first pipeline 3 for storage, and enters the next stage compressor 1 through the second pipeline 5 for further compression. In the energy release state, the gas in the gas storage structure 2 enters the expander 9 through the fourth pipeline 10, drives the expander 9 to do work, and drives the generator 22 to generate electricity.

[0052] In one embodiment, the air pressure in the multiple compressors 1 increases successively in the order of series connection, and the air pressure in the multiple gas storage structures 2 increases successively corresponding to the order of series connection of the multiple compressors 1. The embodiment of the present invention can form multiple levels of energy storage and energy release by setting multiple compressors 1 and gas storage structures 2 with different air pressures. Then, according to the strength of the actual input power supply 21, the corresponding one or more energy storage devices and the combination formed by the energy release device can be selected to ensure the stable operation of the compressor 1 under the design scenario and improve the energy storage efficiency of the multi-stage compressed air energy storage system.

[0053] In addition, because the adjacent compressors 1, gas storage structures 2 and expanders 9 are connected by pipelines and have different gas pressures, graded energy storage and graded energy storage are formed. When different compressor 1 combinations are switched, the gas pressure can be released through the connected pipelines to increase the switching speed.

[0054] In some other embodiments, in order to avoid excessive gas loss in the subsequent gas storage structure 2, resulting in its gas pressure being lower than that of the previous gas storage structure 2. The order here refers to the order of the above-mentioned series connection. A pressure sensor is provided in each gas storage structure 2. When the pressure sensor detects that the gas pressures in adjacent gas storage structures 2 are the same, the third switch valve 8 on the third pipeline 7 connecting the two gas storage structures 2 is opened, so that the gas in the previous gas storage structure 2 can supplement the gas storage structure 2 in the subsequent gas storage structure 2 to increase the gas pressure of the subsequent gas storage structure 2.

[0055] In addition, the air storage structure 2 can be supplemented with gas by the compressor 1 to compress the air and increase its air pressure. Of course, the air pressure of the rear air storage structure 2 can also be increased by the compressor 1 compressing the air and opening the third switch valve 8 on the third pipeline 7 connecting the two air storage structures 2 at the same time.

[0056] In one embodiment, Figure 6 As shown, the expander 9 is connected to another adjacent low-pressure gas storage structure 2 through the sixth pipeline 13, and a sixth switch valve 14 is provided on the sixth pipeline 13. When the load of the input power supply 21 is too small to drive all the compressors 1, and the gas storage in the gas storage structure 2 is insufficient, the sixth switch valve 14 can be opened to transport the sub-high pressure gas generated by the expander 9 through the sixth pipeline 13 to another adjacent low-pressure gas storage structure 2 to supplement the gas storage in the gas storage structure 2, thereby improving energy utilization, saving energy consumption and the working efficiency of the multi-stage compressed air energy storage system.

[0057] In one embodiment, Figure 1 As shown, the fourth pipeline 10 is connected to the third pipeline 7, and the connecting point between the fourth pipeline 10 and the third pipeline 7 is located between the third switch valve 8 and the gas storage structure 2, which can simplify the pipeline connection and reduce the use cost.

[0058] In one embodiment, Figure 1 As shown, the first pipeline 3 is connected to the second pipeline 5, which can further simplify the pipeline connection and reduce the use cost. Figure 2 As shown, the first pipeline 3 is further provided with a first one-way valve 18, which is located between the first heat exchange portion 15 and the connection between the first pipeline 3 and the second pipeline 5. The first one-way valve 18 can effectively prevent the gas from flowing back from the first pipeline 3 to the compressor 1.

[0059] In one embodiment, the first switch valve 4 and the fourth switch valve 11 are both two-way valves. The first switch valve 4 is a two-way valve, and the gas of the gas storage structure 2 can also enter the next higher pressure compressor 1 through the first pipeline 3 and the second pipeline 5, which is conducive to improving the switching speed of different combinations of the compressor 1. Similarly, the fourth switch valve 11 is a two-way valve, and the gas of the expander 9 can enter the next lower pressure gas storage structure 2 through the fourth pipeline 10, which improves the switching speed of different combinations of the compressor 1, thereby improving the working efficiency of the multi-stage compressed air energy storage system.

[0060] It should be noted that the above-mentioned valves may adopt any existing structure, such as a solenoid valve, a mechanical valve, etc., and the embodiments of the present invention do not limit this, and the specific settings may be selected according to actual needs.

[0061] In one embodiment, the energy storage device is connected to the energy release device in a one-to-one correspondence, and each energy storage device and the corresponding energy release device can operate independently, and drive at least one compressor 1 based on the strength of the input power supply 21. The embodiment of the present invention can select one or more compressors 1 and their corresponding gas storage structures 2 and expanders 9 to store and release compressed air energy according to the strength of the input power supply 21, effectively meeting the use requirements of different input power supplies 21 in different scenarios, thereby improving the working efficiency of the multi-stage compressed air energy storage system.

[0062] Since each energy storage device and the corresponding energy release device can operate independently, in some other embodiments, it is also possible to enter the energy storage state and the energy release state at the same time through different energy storage devices and energy release devices to meet the needs of special usage scenarios.

[0063] In one embodiment, Figure 1 As shown, four energy storage devices and four energy release devices are respectively provided to form a four-stage compressed air energy storage system as an example. Compressor 1 is recorded as the first compressor, the second compressor, the third compressor and the fourth compressor from high to low air pressure. Gas storage structure 2 is recorded as the first gas storage structure, the second gas storage structure, the third gas storage structure and the fourth gas storage structure from high to low air pressure. Expander 9 is recorded as the first expander, the second expander, the third expander and the fourth expander from high to low air pressure.

[0064] It is understandable that, in some other embodiments, the multi-stage compressed air energy storage system may also include three, five or more energy storage devices and energy release devices, which is not limited by the embodiments of the present invention.

[0065] The embodiments of the present invention can meet several scenarios including but not limited to the following.

[0066] Scene 1

[0067] like Figure 2As shown, when the input power supply 21 can only drive one compressor 1 to work. Select the second compressor, one of the third compressor and the fourth compressor to form a single-stage compressed air energy storage system. Take the selection of the second compressor as an example. In the energy storage state, the input power supply 21 drives the second compressor to compress and pressurize the air, and the pressurized gas enters the second gas storage structure through the first pipeline 3 for storage. Among them, the second compressor can be connected to the outside air or the gas in the first gas storage structure. In the energy release state, the gas in the second gas storage structure enters the second expander, and the second expander drives the generator 22 to generate electricity.

[0068] Scene 2

[0069] like Figure 3 As shown, when the input power source 21 can drive two compressors 1 to work, two adjacent ones of the first compressor, the second compressor and the third compressor are selected to form a two-stage compressed air energy storage system, or two non-adjacent ones are selected to form two of the above-mentioned single-stage compressed air energy storage systems.

[0070] Take the selection of the first compressor and the second compressor to form a two-stage compressed air energy storage system as an example. In the energy storage state, the input power supply 21 drives the first compressor and the second compressor to compress and pressurize the air respectively. The gas pressurized by the first compressor enters the first gas storage structure through the first pipeline 3 for storage, and enters the second compressor through the second pipeline 5 for further compression. The gas pressurized by the second compressor enters the second gas storage structure through the first pipeline 3 for storage. In the energy release state, the gas in the first gas storage structure enters the first expander, and the first expander drives the generator 22 to generate electricity. The gas in the second gas storage structure enters the second expander, and the second expander drives the generator 22 to generate electricity. The sub-pressure gas generated by the second expander enters the first expander at the same time.

[0071] When the input power supply 21 is capable of driving three or all compressors 1 to work, and so on, for the sake of brevity, a detailed description is not given here.

[0072] Scene 3

[0073] If the gas storage in all gas storage structures 2 is sufficient, when the input power 21 can drive all compressors 1 to work, all fourth switch valves 11 are closed. Figure 4 As shown, the first compressor, the second compressor and the third compressor only transport the compressed gas to the subsequent compressors one by one until the fourth compressor, that is, only the fourth gas storage structure is left to store the compressed gas. Figure 5 As shown, the gas stored in the fourth gas storage structure is transported to the third gas storage structure, the second gas storage structure and the first gas storage structure in sequence, providing gas for all the expanders 9 respectively, and driving all the generators 22 to generate electricity respectively.

[0074] Scene 4

[0075] If the gas storage in the gas storage structure 2 is insufficient, when the input power 21 is able to drive all the compressors 1 to work, all the fourth switch valves 11 are opened, and all the sixth switch valves 14 are closed. The first compressor, the second compressor, and the third compressor transport the compressed gas part to the following compressor 1 one by one until the fourth compressor, and then transport part of the gas to the corresponding gas storage structure 2. Figure 6 As shown, each gas storage structure 2 has an independent compressor 1 to provide gas, and transports the gas to each expander 9 to drive each generator 22 to generate electricity.

[0076] In one embodiment, the multi-stage compressed air energy storage system further includes a heat exchanger, which is disposed on the first pipeline 3 and is used to absorb the heat released by the compressor 1 and reduce the gas temperature in the first pipeline 3. The embodiment of the present invention can recover the waste heat generated when the compressor 1 compresses the gas by arranging a heat exchanger, thereby improving energy utilization and saving energy consumption.

[0077] It should be noted that the embodiments of the present invention do not limit the heat exchanger. Exemplarily, the heat exchanger includes a first heat exchange part 15 and a second heat exchange part 16 connected to each other. The first heat exchange part 15 is arranged in the first pipeline 3, between the compressor 1 and the first switch valve 4, and is used to absorb the heat released by the compressor 1. The second heat exchange part 16 is arranged in the fourth pipeline 10, between the fourth switch valve 11 and the expander 9, and is used to heat the gas in the fourth pipeline 10. The heat exchanger recovers the waste heat generated when the compressor 1 compresses the gas through the first heat exchange part 15, and heats the gas in the fourth pipeline 10 with the recovered heat through the second heat exchange part 16. After that, the gas enters the expander 9, which is beneficial for the expander 9 to drive the generator 22 to generate electricity, and further improves the energy utilization rate.

[0078] Furthermore, the heat exchanger further includes a third heat exchange part 17, which is connected to the first heat exchange part 15 and is arranged in the fifth pipeline 12. The heat recovered by the first heat exchange part 15 of the heat exchanger can also heat the gas in the fifth pipeline 12 through the third heat exchange part 17. After the gas is heated, it enters the expander 9 with a lower pressure from the expander 9 with a higher pressure, which is beneficial for the expander 9 with a lower pressure to drive the generator 22 to generate electricity.

[0079] In one embodiment, the energy storage device further includes an air inlet pipe 19, the compressor 1 includes an air inlet, and the air inlet is connected to the air inlet pipe 19. The energy release device also includes an exhaust pipe 20, and the expander 9 includes an air outlet, and the air outlet is connected to the exhaust pipe 20. The compressor 1 can access the gas in the air inlet pipe 19 from the air inlet, and store it in the gas storage structure 2 after compression. The gas in the gas storage structure 2 then enters the expander 9, drives the engine to generate electricity, and is finally discharged from the air outlet through the exhaust pipe 20. Each compressor 1 is provided with an air inlet, and each expander 9 is provided with an air outlet, so that each energy storage device and each energy release device can operate independently.

[0080] In one embodiment, the capacity of the gas storage structure 2 and the ratio of each gas storage structure 2 can be designed according to the actual power demand. For example, the pressure difference between adjacent gas storage structures 2 is between 2MPa and 3MPa, which is conducive to the efficient and stable operation of the compressor 1.

[0081] It should be noted that the embodiment of the present invention does not limit the compressor 1, and the compressor 1 can select any existing structure as needed. The compressor 1 can include at least one of a piston compressor, a rotary compressor, a centrifugal compressor, an axial compressor, and a hybrid compressor.

[0082] In addition, the embodiment of the present invention does not limit the expander 9, and the expander 9 includes at least one of a piston expander, a rotary expander, and a turbine expander. The embodiment of the present invention can directly adopt various existing compressors 1 and various expanders 9, which has low use cost and is conducive to promotion.

[0083] In one embodiment, the gas storage structure 2 includes at least one of a gas storage tank, an underground salt cavern, an artificial underground chamber, a pipeline steel bundle gas storage reservoir, and an air bag. The gas storage structure 2 of the present invention can be applied to a variety of work scenarios to increase the scope of use of the multi-stage compressed air energy storage system. It is understandable that the gas storage structure 2, in addition to the above-mentioned form, can also be any other structure that has pressure bearing and sealing properties and can store gas.

[0084] In order to realize the basic functions of the multi-stage compressed air energy storage system, the multi-stage compressed air energy storage system in this embodiment may also include other necessary modules or components, such as wires, controllers, etc. It should be noted that the other necessary modules or components included in the multi-stage compressed air energy storage system can be of any suitable existing structure. In order to clearly and briefly illustrate the technical solution provided by this embodiment, the above-mentioned parts will not be repeated here, and the drawings in the specification have also been simplified accordingly. However, it should be understood that the scope of the embodiments of the present invention is not limited by this.

[0085] According to an embodiment of the present invention, on the other hand, a power station is also provided, which mainly includes: multiple input power sources 21, multiple generators 22 and a multi-stage compressed air energy storage system. The input power source 21 is connected to the compressor 1 in the multi-stage compressed air energy storage system, and is used to drive the compressor 1 to compress air. The generator 22 is connected to the expander 9, and is used to be driven by the expander 9 and generate electricity. Because the power station includes a multi-stage compressed air energy storage system, it has the same effect as the multi-stage compressed air energy storage system, that is, it can form multiple independent compressed air energy storage structures, which do not affect each other and are stable to use. It can also form multi-stage graded regulation and quickly switch different compressor 1 combinations, which can meet the use conditions of the input power source 21 in a fluctuating scenario and improve the use effect of the multi-stage compressed air energy storage system.

[0086] Specifically, the power station includes but is not limited to a wind power station, a photovoltaic power station, etc. The input power source 21 can be a generator, and each generator drives a compressor 1 separately. The embodiment of the present invention can realize that power stations such as wind power stations and photovoltaic power stations directly store electricity after generating electricity, and output the electricity stably to the power grid, thereby alleviating the impact of fluctuations in power generation of renewable energy such as wind power stations and photovoltaic power stations on the power grid.

[0087] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A multi-stage compressed air energy storage system, characterized in that: include: A plurality of energy storage devices and a plurality of energy release devices; Each of the energy storage devices comprises: A compressor (1) adapted to be connected to an input power source (21) and driven by the input power source (21); The gas storage structure (2) is connected to the compressor (1) via a first pipeline (3); a first switch valve (4) is provided on the first pipeline (3); The plurality of compressors (1) are connected in series via a second pipeline (5), and a second switch valve (6) is provided on the second pipeline (5); the plurality of gas storage structures (2) are connected in series via a third pipeline (7), and a third switch valve (8) is provided on the third pipeline (7); Each of the energy release devices comprises: An expander (9) is connected to the gas storage structure (2) via a fourth pipeline (10); a fourth switch valve (11) is provided on the fourth pipeline (10); the expander (9) is suitable for connecting to a generator (22) and driving the generator (22) to generate electricity; The plurality of expanders (9) are connected in series in sequence via a fifth pipeline (12), and the fifth pipeline (12) is provided with a fifth switch valve; The air pressure in the plurality of compressors (1) increases successively in the order in which they are connected in series, and the air pressure in the plurality of air storage structures (2) increases successively in correspondence with the order in which the plurality of compressors (1) are connected in series; The expander (9) is connected to another adjacent low-pressure gas storage structure (2) via a sixth pipeline (13), and a sixth switch valve (14) is provided on the sixth pipeline (13); The fourth pipeline (10) is connected to the third pipeline (7), and the connecting point between the fourth pipeline (10) and the third pipeline (7) is located between the third switch valve (8) and the gas storage structure (2); The first pipeline (3) is in communication with the second pipeline (5); the first pipeline (3) is also provided with a first one-way valve (18), and the first one-way valve (18) is located between the first heat exchange portion (15) and the connection between the first pipeline (3) and the second pipeline (5); The first switch valve (4) and the fourth switch valve (11) are both two-way valves; The energy storage device is connected to the energy release device in a one-to-one correspondence, and each of the energy storage devices and the corresponding energy release device can operate independently and drive at least one compressor (1) based on the strength of the input power supply (21); The multi-stage compressed air energy storage system further comprises a heat exchanger, wherein the heat exchanger is arranged on the first pipeline (3) and is used to absorb heat released by the compressor (1); The heat exchanger comprises a first heat exchange portion (15) and a second heat exchange portion (16) which are connected to each other. The first heat exchange portion (15) is arranged in the first pipeline (3), between the compressor (1) and the first switch valve (4), and is used to absorb heat released by the compressor (1); the second heat exchange portion (16) is arranged in the fourth pipeline (10), between the fourth switch valve (11) and the expander (9), and is used to heat the gas in the fourth pipeline (10).

2. The multi-stage compressed air energy storage system according to claim 1, characterized in that: The heat exchanger further comprises a third heat exchange portion (17), the third heat exchange portion (17) being in communication with the first heat exchange portion (15) and being arranged in the fifth pipeline (12).

3. The multi-stage compressed air energy storage system according to claim 1, characterized in that: The energy storage device further comprises an air inlet pipe (19), the compressor (1) comprises an air inlet port, and the air inlet port is in communication with the air inlet pipe (19); the energy release device further comprises an exhaust pipe (20), the expander (9) comprises an exhaust port, and the exhaust port is in communication with the exhaust pipe (20).

4. The multi-stage compressed air energy storage system according to any one of claims 1 to 3, characterized in that: The compressor (1) comprises at least one of a piston compressor, a rotary compressor, a centrifugal compressor, an axial compressor and a hybrid compressor.

5. The multi-stage compressed air energy storage system according to any one of claims 1 to 3, characterized in that: The expander (9) comprises at least one of a piston expander, a rotary expander and a turbine expander.

6. The multi-stage compressed air energy storage system according to any one of claims 1 to 3, characterized in that: The gas storage structure (2) comprises at least one of a gas storage tank, an underground salt cavern, an artificial underground chamber, a pipeline steel bundle gas storage reservoir, and an air bag.

7. A power station, characterized in that: include: Multiple input power supplies (21); multiple generators (22); The multi-stage compressed air energy storage system according to any one of claims 1 to 6, wherein the input power supply (21) is connected to the compressor (1) in the multi-stage compressed air energy storage system, and is used to drive the compressor (1) to compress air; The generator (22) is connected to the expander (9) and is used to be driven by the expander (9) and generate electricity.

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