Compressed gas energy storage expansion system and method

Abstract

The invention provides a compressed gas energy storage expansion system and method.The system comprises a gas storage device and a gas expansion power generation subsystem, compressed gas is stored in the gas storage device, and the gas expansion power generation subsystem is used for making the compressed gas expand to do work and driving a power generator to generate electric energy; the speed-adjustable expansion machine and the first power generator are arranged between the gas storage device and the gas expansion power generation subsystem; the speed-adjustable expansion machine is connected with the gas storage device and the gas expansion power generation subsystem through gas pipelines. The speed-adjustable expansion machine is arranged to serve as an exhaust, pressure reduction and pressure stabilization mode of the gas storage device, the speed-adjustable expansion machine drives the generator to output electric energy, part of energy of the gas storage device in the pressure drop interval of reducing from high pressure to stable low pressure is recycled, the purpose of clean and efficient energy storage is achieved, and the total amount of electric energy capable of being output by the system is increased.

Description

Technical Field

[0001] This article relates to but is not limited to the field of gas compression energy storage technology, and in particular to but is not limited to a compressed gas energy storage expansion system and method. Background Art

[0002] Compressed gas energy storage power station is a large-scale, long-term energy storage technology with great application potential. The large-scale storage of compressed gas requires a large-capacity gas storage device. At present, artificial pressure vessels, underground salt caverns, artificially constructed caves, etc. are generally used for gas storage. The volume of such gas storage devices is fixed. According to the fixed volume charging and discharging principle, when such gas storage devices are deflated, as the deflation process proceeds, the amount of compressed gas in the gas storage device continues to decrease and the deflation pressure gradually decreases, which in turn causes the subsequent gas expander's intake pressure to continue to decrease. When the pressure drop range of the gas storage device is large, it brings great difficulties to the design and operation of the gas expander. Therefore, in actual engineering, a throttling pressure-stabilizing valve is added to stabilize the exhaust gas of the gas storage device at a fixed pressure through throttling, and then enter the gas expander to expand, do work, and generate electricity.

[0003] Reference Figure 1 As shown, the exhaust gas of the gas storage device (AS) is stabilized at a fixed pressure P after passing through the throttling pressure regulating valve (TV). The pressure is generally the minimum storage pressure of the gas storage device AS. The compressed gas with a pressure of P is heated by the heat exchanger (HX1) and enters the first-stage expander (TB1) to expand and do work. Then, it is reheated by the heat exchanger (HX2) and enters the second-stage expander (TB2) to do work. Finally, the exhaust gas enters the environment. The first-stage expander TB1 and the second-stage expander TB2 jointly drive the generator (G1) to output electricity. Since the intake pressure of the expander system is stable, the output power can be stable, thereby achieving friendly grid connection.

[0004] However, during the throttling process, the throttling pressure regulating valve TV throttles the compressed gas in the gas storage device from high pressure to pressure P, and the energy in this pressure range will be completely lost; at the same time, since the temperature of the compressed gas will drop sharply during the throttling process, more heat is required in the subsequent heat exchanger HX1 to rise to the expander inlet temperature, thus increasing the energy consumption of the system. The increase in energy loss and energy consumption will jointly lead to a decrease in the total amount of electrical energy that can be output by the system and a decrease in the energy storage efficiency of the system. Summary of the invention

[0005] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0006] The purpose of the present disclosure is to provide a compressed gas energy storage and expansion system and method to solve the problems of unstable output pressure during the deflation process of the gas storage device, or energy loss during the throttling expansion process and increased energy consumption due to throttling and cooling of the compressed gas, to ensure the stable operating conditions of the gas expansion power generation subsystem, and to enhance the ability of the compressed gas energy storage and expansion system to output electrical energy to the outside.

[0007] The present disclosure provides a compressed gas energy storage and expansion system, the compressed gas energy storage and expansion system comprising:

[0008] a gas storage device configured to store compressed gas;

[0009] a gas expansion power generation subsystem configured to generate power using the compressed gas expansion;

[0010] An adjustable speed expander, wherein the air inlet of the adjustable speed expander is connected to the air outlet of the gas storage device through a gas pipeline, and the air outlet of the adjustable speed expander is connected to the air inlet of the gas expansion and generation subsystem through a gas pipeline;

[0011] The first generator is configured to convert mechanical energy generated when the compressed gas passes through the adjustable speed expander into electrical energy.

[0012] In some embodiments provided by the present disclosure, the compressed gas energy storage expansion system further comprises:

[0013] a heater, the heater being configured to heat the gas in the gas pipeline between the adjustable speed expander and the gas expansion and power generation subsystem, and / or to heat the gas in the gas pipeline within the gas expansion and power generation subsystem, and / or to heat the gas in the gas pipeline between the adjustable speed expander and the gas storage device;

[0014] The heater is powered by the first generator.

[0015] In some embodiments provided by the present disclosure, the gas expansion power generation subsystem includes: a heat exchanger and a subsystem expander;

[0016] The heat exchanger and the subsystem expander are connected in series in sequence through a gas pipeline; one subsystem heat exchanger and one expander are recorded as a power generation unit, and the number of power generation units of the gas expansion power generation subsystem can be one or more than two;

[0017] a second generator configured to convert mechanical energy generated by compressed gas passing through the subsystem expander into electrical energy;

[0018] One or more of the subsystem expanders corresponds to one of the second generators.

[0019] In some embodiments provided by the present disclosure, the gas expansion and power generation subsystem includes: a first heat exchanger, a primary expander, a second heat exchanger and a secondary expander, and a second generator, which are sequentially connected in series through a gas pipeline;

[0020] The first heat exchanger is configured to exchange heat with gas in a gas pipeline between the heater and the first-stage expander;

[0021] The second heat exchanger is configured to perform heat exchange on a gas pipeline between the first-stage expander and the second-stage expander;

[0022] The second generator is configured to convert mechanical energy generated when compressed gas passes through the first-stage expander and the second-stage expander into electrical energy.

[0023] In another aspect, the present disclosure provides a compressed gas energy storage expansion method, using the above-mentioned compressed gas energy storage expansion system, the compressed gas energy storage expansion method comprising:

[0024] Controlling the gas storage device to release the compressed gas to the adjustable speed expander;

[0025] The adjustable speed expander rotates under the action of the compressed gas, and the adjustable speed expander drives the first generator to rotate. When the intake pressure of the adjustable speed expander drops from the first pressure to the second pressure, the gas storage device stops releasing the compressed gas to the adjustable speed expander;

[0026] The adjustable speed expander controls the exhaust pressure to be stabilized to a second pressure by a speed condition;

[0027] Wherein, the first pressure is greater than the second pressure.

[0028] In some embodiments provided by the present disclosure, when the compressed gas energy storage expansion system further includes a heater, and the heater is configured to heat the gas in the gas pipeline between the adjustable speed expander and the gas expansion power generation subsystem, and / or heat the gas in the gas pipeline within the gas expansion power generation subsystem, and / or heat the gas in the gas pipeline between the adjustable speed expander and the gas storage device, the method further includes:

[0029] During the process of the intake pressure of the adjustable speed expander dropping to the second pressure, the first generator outputs electric energy to the heater, and the heater heats the gas in the gas pipeline (for example, electric or heat pump heating); the compressed gas is heated and depressurized by the heater, and the heated and depressurized compressed gas is output to the gas expansion and generating subsystem.

[0030] In some embodiments provided by the present disclosure, when the gas expansion power generation subsystem includes: a heat exchanger and a subsystem expander, and one or more of the subsystem expanders corresponds to one second generator, the method further includes:

[0031] The compressed gas heated and depressurized by the adjustable speed expander and the heater enters the heat exchanger for heating, and the compressed gas heated by the heater enters the subsystem expander;

[0032] The subsystem expander rotates under the action of the compressed gas to drive the second generator to generate electricity.

[0033] In some embodiments provided by the present disclosure, when the gas expansion and power generation subsystem includes: a first heat exchanger, a primary expander, a second heat exchanger and a secondary expander, and a second generator connected in series in sequence through a gas pipeline, the method further includes:

[0034] The compressed gas heated and depressurized by the adjustable speed expander and the heater enters the first heat exchanger for heating, and the compressed gas heated by the first heat exchanger enters the first-stage expander;

[0035] The compressed gas after passing through the first-stage expander enters the second heat exchanger for heating, and the compressed gas after being heated by the second heat exchanger enters the second-stage expander;

[0036] The secondary expander rotates under the action of the compressed gas;

[0037] The first-stage expander and the second-stage expander drive the second generator to rotate and generate electricity.

[0038] On the other hand, a control system is provided in an embodiment of the present disclosure, which includes a processor, a memory, and a computer program stored in the memory and executable on the processor, and the computer program implements the steps of the above-mentioned compressed gas energy storage and expansion method when executed by the processor.

[0039] On the other hand, a computer-readable storage medium is provided in an embodiment of the present disclosure, wherein a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the steps of the above-mentioned compressed gas energy storage and expansion method are implemented.

[0040] The beneficial effects of the above technical solution disclosed in the present invention are as follows:

[0041] The technical solution provided by the present invention is to set an adjustable speed expander and a first generator between the gas storage device and the gas expansion and power generation subsystem, control the gas storage device to release compressed gas to the adjustable speed expander, and the adjustable speed expander rotates under the action of the compressed gas, and the rotation of the adjustable speed expander drives the rotation of the first generator, so that in the process of reducing the intake pressure of the adjustable speed expander from the first pressure to the second pressure, this part of the energy involved can be converted into electrical energy, and part of the energy in the pressure drop range of the gas storage device from high pressure to stable low pressure can be recovered, thereby achieving the purpose of clean and efficient energy storage, and improving the total output power and energy storage efficiency of the system; at the same time, the adjustable speed expander can always stabilize the exhaust pressure at the second pressure by adjusting the rotation speed, so that the gas expansion subsystem can operate efficiently under stable working conditions, further improving the energy storage efficiency of the system.

[0042] Other features and advantages of the present disclosure will be described in the following description, and partly become apparent from the description, or be understood by implementing the present disclosure. Other advantages of the present disclosure can be invented and obtained by the schemes described in the description. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The accompanying drawings are used to provide an understanding of the technical solution of the present disclosure and constitute a part of the specification. Together with the embodiments of the present disclosure, they are used to explain the technical solution of the present disclosure and do not constitute a limitation on the technical solution of the present disclosure.

[0044] Figure 1 It is a structural schematic diagram of a compressed gas energy storage system in the prior art;

[0045] Figure 2 This is one of the structural schematic diagrams of the compressed gas energy storage and expansion system provided in an embodiment of the present disclosure;

[0046] Figure 3 The second structural schematic diagram of the compressed gas energy storage and expansion system provided by the embodiment of the present disclosure;

[0047] Figure 4 A schematic flow chart of a compressed gas energy storage and expansion method provided in an embodiment of the present disclosure.

[0048] Figure numerals: 1. gas storage device; 2. gas expansion and generation subsystem; 3. adjustable speed expander; 4. first generator; 5. heater; 6. first heat exchanger; 7. first-stage expander; 8. second heat exchanger; 9. second-stage expander; 10. second generator; 11. throttling pressure-stabilizing valve. DETAILED DESCRIPTION

[0049] To make the purpose, technical solution and advantages of the present disclosure more clear, the embodiments of the present disclosure are described in detail below. It should be noted that the embodiments and features in the embodiments of the present disclosure can be combined with each other arbitrarily without conflict.

[0050] like Figure 2 and Figure 3 As shown, in an embodiment of the present disclosure, a compressed gas energy storage expansion system is exemplarily provided, and the compressed gas energy storage expansion system includes:

[0051] A gas storage device 1, configured to store compressed gas;

[0052] A gas expansion power generation subsystem 2, configured to generate power using the compressed gas expansion;

[0053] An adjustable speed expander 3, the air inlet of the adjustable speed expander 3 is connected to the air outlet of the gas storage device 1 through a gas pipeline, and the air outlet of the adjustable speed expander 3 is connected to the air inlet of the gas expansion and generation subsystem 2 through a gas pipeline;

[0054] The first generator 4 is configured to convert the mechanical energy generated when the compressed gas passes through the adjustable speed expander 3 into electrical energy.

[0055] The connection through the gas pipeline is a fluid connection of the compressed gas, which is different from the shaft connection of the expander and the generator.

[0056] For example, Figure 3 As shown, the compressed gas energy storage expansion system also includes:

[0057] A heater 5, wherein the heater 5 is configured to heat the gas in the gas pipeline between the adjustable speed expander 3 and the gas expansion and power generation subsystem 2, and / or heat the gas in the gas pipeline within the gas expansion and power generation subsystem 2, and / or heat the gas in the gas pipeline between the adjustable speed expander 3 and the gas storage device 1;

[0058] The heater 5 is powered by the first generator 4 .

[0059] In some embodiments provided by the present disclosure, the gas expansion power generation subsystem includes: a heat exchanger and a subsystem expander;

[0060] The heat exchanger and the subsystem expander are connected in series in sequence through a gas pipeline; one subsystem heat exchanger and one expander are recorded as a power generation unit, and the number of power generation units of the gas expansion power generation subsystem can be one or more than two;

[0061] a second generator 10, the second generator being configured to convert mechanical energy generated when compressed gas passes through the subsystem expander into electrical energy;

[0062] One or more of the subsystem expanders corresponds to one of the second generators.

[0063] For example, the gas expansion power generation subsystem 2 may be composed of one or more expanders, and correspondingly may also have one or more heat exchangers. At least one heat exchanger, at least one expander, and a second generator may be used to achieve the purpose of expansion work and power generation; the expander in the gas expansion power generation subsystem 2 may be a non-adjustable speed expander. The specific number of expanders and heat exchangers is set according to actual needs, and no specific restrictions are made here.

[0064] Exemplarily, the gas expansion and power generation subsystem includes: a first heat exchanger 6, a primary expander 7, a second heat exchanger 8 and a secondary expander 9, and a second generator 10, which are sequentially connected in series through a gas pipeline;

[0065] The first heat exchanger 6 is configured to perform heat exchange on the gas in the gas pipeline between the heater 5 and the first-stage expander 7;

[0066] The second heat exchanger 9 is configured to perform heat exchange on the gas pipeline between the first-stage expander 7 and the second-stage expander 9;

[0067] The second generator 10 is configured to convert mechanical energy generated when the compressed gas passes through the first-stage expander 7 and the second-stage expander 9 into electrical energy.

[0068] like Figure 3 As shown, the first-stage expander 7, the second-stage expander 9 and the second generator 10 are coaxially connected to generate electricity.

[0069] On the other hand, in an embodiment of the present disclosure, a compressed gas energy storage expansion method is exemplarily provided, using the above-mentioned compressed gas energy storage expansion system, and the compressed gas energy storage expansion method includes:

[0070] The gas storage device 1 is controlled to release the compressed gas to the adjustable speed expander 3; the adjustable speed expander 3 rotates under the action of the compressed gas, and since the output end of the adjustable speed expander 3 is connected to the first generator 4, the adjustable speed expander 3 rotates to drive the first generator 4 to rotate and generate electricity. The present disclosure sets an adjustable speed expander 3 after the gas storage device 1 to replace the throttling pressure regulating valve, and can exhaust and reduce the pressure of the gas storage device 1 by variable speed expansion and maintain it at a constant pressure, thereby ensuring the stability of the intake pressure of the conventional gas expansion unit in the subsequent gas expansion and power generation subsystem 2, and reducing its design and operation difficulty.

[0071] The adjustable speed expander rotates under the action of the compressed gas, and the adjustable speed expander drives the first generator to rotate. When the intake pressure of the adjustable speed expander drops from the first pressure to the second pressure, the gas storage device stops releasing the compressed gas to the adjustable speed expander;

[0072] The adjustable speed expander controls the exhaust pressure to be stabilized to a second pressure by a speed condition;

[0073] Wherein, the first pressure is greater than the second pressure.

[0074] In the process of reducing the intake pressure of the adjustable speed expander 3 from the first pressure to the second pressure, this part of the energy involved is converted into electrical energy, so that part of the energy in the pressure drop range from high pressure to stable low pressure of the gas storage device is recovered, the purpose of clean and efficient energy storage is achieved, and the total output electrical energy and energy storage efficiency of the system are improved; at the same time, the adjustable speed expander adjusts the speed to keep the exhaust pressure stable at the second pressure, so that the gas expansion power generation subsystem 2 can operate efficiently under stable working conditions, further improving the system energy storage efficiency.

[0075] Exemplarily, the first pressure is the maximum gas storage pressure PH of the gas storage device 1, and the second pressure is the minimum gas storage pressure PL of the gas storage device. The energy generated in the process of reducing the pressure from the first pressure to the second pressure of the gas storage device 1 is used to generate electricity through the adjustable speed expander 3 and the first generator 4, thereby achieving the purpose of clean and efficient energy storage and improving the total amount of electrical energy that can be output by the system and the energy storage efficiency.

[0076] Since the gas storage device 1 is reduced from the highest gas storage pressure PH to the lowest gas storage pressure PL, the speed of the adjustable speed expander 3 gradually decreases as the pressure of the gas storage device 1 decreases. In this process, the speed of the first generator 4 driven by the adjustable speed expander 3 is also continuously reduced, and the frequency of the output electric energy is continuously reduced until the pressure of the gas storage device 1 is reduced to the lowest gas storage pressure PL, the adjustable speed expander 3 stops expanding, and the first generator 4 stops running. In the present disclosure, this part of electric energy is consumed by the heater 5, and the electric energy with a changed frequency can be used for the resistive load of the heater 5, and the heater 5 is used to heat the compressed gas passing through the adjustable speed expander 3, and the compressed gas after heating and depressurization is output to the gas expansion and generation subsystem 2.

[0077] Exemplarily, when the compressed gas energy storage expansion system further includes a heater 5, and the heater 5 is configured to heat the gas in the gas pipeline between the adjustable speed expander 3 and the gas expansion and power generation subsystem 2, and / or heat the gas in the gas pipeline within the gas expansion and power generation subsystem 2, and / or heat the gas in the gas pipeline between the adjustable speed expander 3 and the gas storage device 1, the method further includes:

[0078] In the process of the intake pressure of the adjustable speed expander 3 dropping to the second pressure, the first generator outputs electric energy to the heater 5, and the heater 5 heats the gas in the gas pipeline (for example, electric or heat pump heating); the heater 5 heats and depressurizes the compressed gas, and outputs the heated and depressurized compressed gas to the gas expansion and generation subsystem 2.

[0079] Exemplarily, when the gas expansion and power generation subsystem 2 comprises: a heat exchanger and a subsystem expander, and one or more of the subsystem expanders correspond to one of the second generators, the method further comprises:

[0080] The compressed gas heated and depressurized by the adjustable speed expander 3 and the heater 5 enters the heat exchanger for heating, and the compressed gas heated by the heater 5 enters the subsystem expander;

[0081] The subsystem expander rotates under the action of the compressed gas to drive the second generator 10 to generate electricity.

[0082] In some embodiments provided by the present disclosure, when the gas expansion and power generation subsystem includes: a first heat exchanger 6, a primary expander 7, a second heat exchanger 8, a secondary expander 9, and a second generator 10 connected in series in sequence through a gas pipeline, the method further includes:

[0083] The compressed gas heated and depressurized by the adjustable speed expander 3 and the heater 5 enters the first heat exchanger 6 for heating, and the compressed gas heated by the first heat exchanger 6 enters the first-stage expander 7;

[0084] The compressed gas after passing through the first-stage expander 7 enters the second heat exchanger 8 for heating, and the compressed gas after being heated by the second heat exchanger 8 enters the second-stage expander 9;

[0085] The secondary expander 9 rotates under the action of the compressed gas;

[0086] The first-stage expander and the second-stage expander drive the second generator to rotate and generate electricity.

[0087] Exemplarily, the compressed gas that has passed through the heater 5 enters the first heat exchanger 6, and is further heated to the intake temperature of the first-stage expander 7 by using an external hot fluid. The compressed gas then enters the first-stage expander 7 to expand and do work, and is subsequently reheated by the second heat exchanger 8 before entering the second-stage expander 9 to expand and do work, and is finally exhausted into the environment. Since the intake pressures of the first-stage expander 7 and the second-stage expander 9 are stable, stable speed operation can be achieved. Therefore, the second generator 10 driven by the first-stage expander 7 and the second-stage expander 9 can output electrical energy with a stable frequency, which can enter the power grid through the transmission system or be directly supplied to users with high requirements for power quality.

[0088] In summary, the present disclosure achieves the following beneficial effects:

[0089] An adjustable speed expander is installed after the gas storage device to replace the throttling pressure regulating valve. The gas storage device exhaust pressure can be reduced and maintained at a constant pressure by variable speed expansion, ensuring the stability of the intake pressure of the subsequent conventional gas expansion unit and reducing its design and operation difficulty.

[0090] Secondly, the adjustable speed expander is connected to an independent generator, and an electric heater is installed between the adjustable speed expander and the heat exchanger. The low-quality electric energy output by the generator driven by the adjustable speed expander is used to power the electric heater to heat the gas, thereby converting part of the energy of the sliding pressure section into heat energy and feeding it back to the compressed gas, reducing the energy loss of the system;

[0091] In addition, the electric energy generated by the compressed gas in the sliding pressure section through the adjustable speed expander is used to heat the subsequent heat exchanger inlet air, which can reduce the heat consumption of the compressed gas in the subsequent heat exchange process.

[0092] Reference Figure 4 As shown, the present disclosure also provides a compressed gas energy storage expansion method, which is applied to the compressed gas energy storage expansion system as described in any one of the above items, comprising:

[0093] Step 41, controlling the gas storage device to release compressed gas to the adjustable speed expander;

[0094] In step 42, the adjustable speed expander rotates under the action of compressed gas, and the rotation of the adjustable speed expander drives the first generator to rotate. During the process of the intake pressure of the adjustable speed expander decreasing from the first pressure to the second pressure, the gas storage device stops releasing compressed gas to the adjustable speed expander; the adjustable speed expander controls the exhaust pressure to be stabilized to the second pressure through the speed condition; wherein the first pressure is greater than the second pressure.

[0095] The first pressure may be the maximum gas storage pressure of the gas storage device, and the second pressure may be the minimum gas storage pressure of the gas storage device.

[0096] On the other hand, a control system is provided in an embodiment of the present disclosure, which includes a processor, a memory, and a computer program stored in the memory and executable on the processor, and the computer program implements the steps of the above-mentioned compressed gas energy storage and expansion method when executed by the processor.

[0097] On the other hand, a computer-readable storage medium is provided in an embodiment of the present disclosure, wherein a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the steps of the above-mentioned compressed gas energy storage and expansion method are implemented.

[0098] The exemplary embodiments provided by the present disclosure can achieve:

[0099] 1. Stabilize the intake pressure of the gas expansion generator system to make it operate efficiently in a stable working condition;

[0100] 2. Realize the recycling of pressure energy in the range from the initial pressure of the gas storage device to the intake pressure of the gas expansion generating subsystem, further improving the energy efficiency of the system.

[0101] The method of the embodiment of the present disclosure can also achieve the effect achieved by the above-mentioned compressed gas energy storage expansion system. It can exhaust the gas storage device and reduce the pressure and maintain it at a constant pressure by means of variable speed expansion, thereby ensuring the stability of the intake pressure of the subsequent conventional gas expansion unit; it can also use the low-quality electric energy output by the generator driven by the adjustable speed expander to power the electric heater to heat the gas, thereby converting part of the energy of the sliding pressure section into heat energy and feeding it back to the compressed gas, reducing the energy loss of the system; it can also use the electric energy generated by the adjustable speed expander of the compressed gas in the sliding pressure section to heat the intake of the subsequent heat exchanger, thereby reducing the heat consumption of the compressed gas in the subsequent heat exchange process.

Claims

1. A compressed gas energy storage expansion system, characterized in that: The compressed gas energy storage expansion system includes: a gas storage device configured to store compressed gas; a gas expansion power generation subsystem configured to generate power using the compressed gas expansion; An adjustable speed expander, wherein the air inlet of the adjustable speed expander is connected to the air outlet of the gas storage device through a gas pipeline, and the air outlet of the adjustable speed expander is connected to the air inlet of the gas expansion and generation subsystem through a gas pipeline; The first generator is configured to convert mechanical energy generated when the compressed gas passes through the adjustable speed expander into electrical energy.

2. The compressed gas energy storage expansion system according to claim 1, characterized in that: The compressed gas energy storage expansion system also includes: a heater, the heater being configured to heat the gas in the gas pipeline between the adjustable speed expander and the gas expansion and power generation subsystem, and / or to heat the gas in the gas pipeline within the gas expansion and power generation subsystem, and / or to heat the gas in the gas pipeline between the adjustable speed expander and the gas storage device; The heater is powered by the first generator.

3. The compressed gas energy storage expansion system according to claim 2, characterized in that: The gas expansion and power generation subsystem includes: a heat exchanger and a subsystem expander; The heat exchanger and the subsystem expander are connected in series in sequence through a gas pipeline; one subsystem heat exchanger and one expander are recorded as a power generation unit, and the number of power generation units of the gas expansion power generation subsystem can be one or more than two; a second generator configured to convert mechanical energy generated by compressed gas passing through the subsystem expander into electrical energy; One or more of the subsystem expanders corresponds to one of the second generators.

4. The compressed gas energy storage expansion system according to claim 2 or 3, characterized in that: The gas expansion and power generation subsystem comprises: a first heat exchanger, a first-stage expander, a second heat exchanger and a second-stage expander, and a second generator, which are sequentially connected in series through a gas pipeline; The first heat exchanger is configured to exchange heat with gas in a gas pipeline between the heater and the first-stage expander; The second heat exchanger is configured to perform heat exchange on a gas pipeline between the first-stage expander and the second-stage expander; The second generator is configured to convert mechanical energy generated when compressed gas passes through the first-stage expander and the second-stage expander into electrical energy.

5. A compressed gas energy storage expansion method, characterized in that: Using the compressed gas energy storage expansion system according to any one of claims 1 to 4, the compressed gas energy storage expansion method comprises: Controlling the gas storage device to release the compressed gas to the adjustable speed expander; The adjustable speed expander rotates under the action of the compressed gas, and the adjustable speed expander drives the first generator to rotate. When the intake pressure of the adjustable speed expander drops from the first pressure to the second pressure, the gas storage device stops releasing the compressed gas to the adjustable speed expander; The adjustable speed expander controls the exhaust pressure to be stabilized to a second pressure by a speed condition; Wherein, the first pressure is greater than the second pressure.

6. The method according to claim 5, characterized in that When the compressed gas energy storage expansion system further includes a heater, and the heater is configured to heat the gas in the gas pipeline between the adjustable speed expander and the gas expansion and power generation subsystem, and / or heat the gas in the gas pipeline within the gas expansion and power generation subsystem, and / or heat the gas in the gas pipeline between the adjustable speed expander and the gas storage device, the method further includes: In the process of the inlet pressure of the adjustable speed expander decreasing to the second pressure, the first generator outputs electric energy to the heater, and the heater heats the gas in the gas pipeline.

7. The method according to claim 6, characterized in that When the gas expansion power generation subsystem includes: a heat exchanger and a subsystem expander, and one or more of the subsystem expanders corresponds to a second generator, the method further includes: The compressed gas heated and depressurized by the adjustable speed expander and the heater enters the heat exchanger for heating, and the compressed gas heated by the heater enters the subsystem expander; The subsystem expander rotates under the action of the compressed gas to drive the second generator to generate electricity.

8. The method according to claim 6 or 7, characterized in that: When the gas expansion and power generation subsystem includes: a first heat exchanger, a first-stage expander, a second heat exchanger and a second-stage expander, and a second generator, which are sequentially connected in series through a gas pipeline, the method further includes: The compressed gas heated and depressurized by the adjustable speed expander and the heater enters the first heat exchanger for heating, and the compressed gas heated by the first heat exchanger enters the first-stage expander; The compressed gas after passing through the first-stage expander enters the second heat exchanger for heating, and the compressed gas after being heated by the second heat exchanger enters the second-stage expander; The secondary expander rotates under the action of the compressed gas; The first-stage expander and the second-stage expander drive the second generator to rotate and generate electricity.

9. A control system, characterized in that: The control system includes a processor, a memory, and a computer program stored in the memory and executable on the processor. When the computer program is executed by the processor, the steps of the compressed gas energy storage expansion method as described in any one of claims 5 to 8 are implemented.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the compressed gas energy storage and expansion method as described in any one of claims 5 to 8 are implemented.

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