Compressed air energy storage system based on underground flexible gas storage and operating method

Abstract

This invention discloses a compressed air energy storage system and its operation method based on underground flexible gas storage. The system includes compression, thermal storage, gas storage, expansion power generation, and control subsystems. The gas storage utilizes an underground flexible composite material gasbag with an external sliding layer and concrete lining layer, connected in parallel with a backup rigid gas tank and a fast switching valve to improve sealing, geological adaptability, and operational safety. The thermal storage subsystem forms a closed-loop heat transfer medium circulation with the reheater, achieving efficient recovery and utilization of multi-stage compression heat. The control subsystem can quickly adjust power according to grid frequency deviations to meet primary frequency regulation requirements. This invention solves the problems of high leakage risk, poor geological adaptability, low system efficiency, and slow frequency regulation response of traditional gas storage devices, offering advantages such as reliable sealing, high efficiency, fast response, and low cost. It is suitable for wind and solar new energy bases, grid peak shaving and frequency regulation, and distributed energy scenarios.

Description

Technical Field

[0001] This invention relates to the field of large-scale physical energy storage technology for compressed air energy storage, specifically to a compressed air energy storage system and its operation method based on underground flexible gas storage. Background Technology

[0002] With the rapid development of new energy installed capacity, the instability and randomness of new energy sources are becoming increasingly prominent, leading to a growing demand for energy storage in the power grid and increasingly stringent stability requirements. Compressed air energy storage (CAES), as an important means of achieving renewable energy consumption and grid peak shaving, is developing rapidly. Numerous CAES projects are emerging both domestically and internationally. Compressed gas energy storage, along with pumped hydro storage, belongs to the field of long-term energy storage and has advantages such as large installed capacity, flexible site selection, short construction period, and environmental friendliness.

[0003] Chinese invention patent CN120487242A proposes a constant-pressure compressed air energy storage system and storage method. It combines an underwater gas storage tank with an artificial chamber gas storage tank, utilizing the balance between hydrostatic pressure and the internal pressure of the air bladder to achieve constant-pressure gas storage. Chinese invention patent CN120231628A proposes a series-parallel integrated flexible sealed coal mine roadway compressed air energy storage tank group structure. Multiple prefabricated integrated rubber flexible air storage bladders are connected in series to form a single roadway gas storage tank, and the single roadway gas storage tanks established in the same manner are connected in parallel to form a coal mine roadway compressed air energy storage tank group. Chinese invention patent CN119508711A discloses a tunnel-type underground gas storage tank combined with temperature control. A series of temperature-controlled zones are sequentially arranged along the axial direction of the gas storage facility within an annular cavity, dividing the cavity into a first temperature-controlled zone and subsequent temperature-controlled zones arranged sequentially. Each temperature-controlled zone contains a water storage bag. A water circulation structure is located outside the gas storage facility and is connected to each water storage bag, forming a circulating water path to address the temperature control problem of tunnel-type underground gas storage facilities. Chinese invention patent CN121066692A proposes a compressed air energy storage system based on a high-temperature heat pump and low-melting-point molten salt to solve the problems of low efficiency and dependence on fossil fuels and geographical conditions in traditional compressed air energy storage, thereby improving the system's thermal utilization.

[0004] For compressed air energy storage systems, various existing patented technologies have proposed numerous optimization methods, but corresponding challenges still exist that require immediate resolution and improvement. These include high leakage risk in the storage chamber, low overall system efficiency, and slow system response. In recent years, both domestic and international researchers have proposed using salt caverns or artificial chambers as storage facilities and have attempted multi-stage heat recovery to improve efficiency; however, technical bottlenecks such as insufficient gas storage sealing and inadequate thermal management remain. Summary of the Invention

[0005] This invention provides a compressed air energy storage system and its operation method based on underground flexible gas storage. It proposes solutions to the technical pain points of conventional compressed air energy storage systems, such as high risk of gas leakage, low overall system efficiency, poor geological adaptability, and slow frequency regulation response. The system improves overall efficiency by forming a closed-loop thermal cycle through multi-stage heat recovery and utilization; it reduces the risk of gas leakage by employing a dual-mode gas storage method consisting of underground flexible gas storage bladders made of TPU (Thermoplastic Polyurethane) and aramid fibers, and a backup rigid gas storage tank; and it enhances the grid's frequency regulation response by adding external interfaces for renewable energy prediction and grid interfaces, and introducing short-time power prediction combined with a multi-objective particle swarm optimization (MOPSO) control strategy.

[0006] The compressed air energy storage system based on underground flexible gas storage includes: a) a compression subsystem, which consists of at least two stages of compressors connected in series, with each compressor outlet connected to a heat exchanger for recovering compression heat; b) a thermal storage subsystem, which includes a high-temperature thermal storage tank, a low-temperature cold storage tank, and a circulation pump. The closed-loop heat transfer medium is selected from heat transfer oils such as biphenyl-diphenyl ether type or high-temperature synthetic heat transfer oil, with an applicable temperature of -30℃ to 320℃. The high-temperature side outlet of the heat exchanger is connected to the high-temperature thermal storage tank, and the low-temperature side outlet is connected to the low-temperature cold storage tank, forming a closed thermal cycle; c) a gas storage subsystem, which includes a flexible composite gas storage bladder buried underground. The gas storage bladder is externally provided with a concrete lining layer and a sliding layer. The sliding layer is used for adapting to... The system adapts to formation deformation and enhances the sealing of the gas storage bladder; d) an expansion and power generation system, comprising at least two stages of expanders and generators connected in series, with a reheater installed before the inlet of each expander. The high-temperature side of the reheater is connected to the high-temperature thermal storage tank, and the low-temperature side outlet is connected to the low-temperature cold storage tank, so as to reheat the high-pressure air using the recovered compression heat; the expander output shaft is drivenly connected to the generator, and the generator output is connected to the power grid to realize power output; e) a control subsystem, comprising a data acquisition sensor group, a control unit, and an external interface. The control unit has a built-in short-time power prediction model and a multi-objective particle swarm optimization (MOPSO) module, used to adjust the operating power of the compression subsystem and the expansion and power generation system and control the system thermal cycle in real time.

[0007] Furthermore, the flexible composite gas storage bladder includes a TPU inner sealing layer, an aramid fiber reinforcement layer, and an outer protective layer. The TPU inner sealing layer is located on the innermost side of the bladder, directly in contact with high-pressure air, and is tightly bonded to the inner side of the aramid fiber reinforcement layer through a hot-melt bonding process. The aramid fiber reinforcement layer is located in the middle layer, completely covering the outside of the TPU inner sealing layer, and is seamlessly integrated with the TPU inner sealing layer. The outer protective layer is located on the outermost side of the bladder, completely covering the outside of the aramid fiber reinforcement layer, and is fixed to the aramid fiber reinforcement layer as an integral structure through adhesive bonding or hot-melt bonding. The design burst pressure of the gas storage bladder is ≥3.5 times the rated operating pressure. This safety redundancy is a common design standard in the high-pressure flexible gas storage container industry, used to prevent the bladder from rupturing due to ground deformation, impact, and fatigue loads. It can be verified through hydrostatic burst tests and long-term pressure aging tests. The bladder maintains a stable seal within a ground stress variation range of ±15%, and the leakage rate meets the safety requirements of underground gas storage projects.

[0008] Furthermore, the flexible air-storage airbag is covered with a concrete lining combined with a sliding layer, forming a flexible-transition-rigid structure from the inside out. The sliding layer is made of a low shear modulus material, and its outer side is not anchored to the concrete lining, allowing it to slide freely relative to the airbag. Its inner side is connected to the airbag by a point-line connection with HDPE anchoring strips, which not only adapts to stratum deformation but also does not restrict the expansion and contraction of the airbag, significantly improving geological adaptability and sealing reliability.

[0009] Furthermore, the gas storage subsystem further includes a backup rigid gas storage tank, which is connected in parallel with the flexible gas storage bladder via a quick-switching valve. The control subsystem monitors the internal pressure and temperature parameters of the bladder in real time. When the pressure change rate is ≥5% / min or the temperature is ≥80℃, it is determined to be an abnormal state, automatically shutting down the flexible gas storage bladder and activating the rigid gas storage tank via the quick-switching valve to ensure continuous and safe operation of the system. The pressure change rate threshold is the early warning standard value for gas leakage / rupture, and the temperature threshold is the upper limit for long-term safe use of TPU material, which can be achieved through real-time data acquisition by sensors and logical judgment by the control unit.

[0010] Furthermore, the heat exchanger adopts an aluminum-magnesium alloy brazed plate-fin structure, and its high-temperature side channel inner wall is provided with a finned heat transfer structure to ensure high recovery efficiency of compression heat and improve the system's cycle energy efficiency.

[0011] Furthermore, the control unit incorporates a power prediction model and a multi-objective particle swarm optimization (MOPSO) model. The power prediction model employs a short-time series prediction model, including one or a combination of moving average prediction, LSTM simplified prediction, and grey prediction, to achieve short-timescale power prediction based on historical operating data and renewable energy output prediction curves. The multi-objective particle swarm optimization (MOPSO) model is used to simultaneously optimize three objectives: system power generation efficiency, frequency regulation response speed, and gas storage operation safety, outputting optimal control commands. The control logic utilizes grid frequency deviation. Closed-loop control, based on the standard control logic for primary frequency regulation, collects the grid frequency deviation in real time. After optimization and calculation, the expander intake flow rate is dynamically adjusted so that the system can output the required power in a short time and meet the primary frequency regulation response requirements of the power grid.

[0012] The operation method of the compressed air energy storage system based on underground flexible gas storage includes the following steps: a) Energy storage stage: The compression subsystem is driven by off-peak electricity to compress ambient air to high pressure. The compression heat generated during the compression process is stored in a high-temperature heat storage tank through a heat exchanger. The cooled high-pressure air is injected into the underground flexible gas storage bladder; b) Energy release stage: During peak grid load, the high-pressure air is released from the flexible gas storage bladder. After absorbing the high-temperature heat storage heat through the reheater, it enters the expansion and power generation system to drive the expander to do work and drive the generator to generate electricity, which is then fed into the grid; c) Heat recovery cycle stage: The heat generated during compression and the cold generated during expansion are recycled through the heat storage subsystem using a heat transfer medium to achieve a closed-loop hot and cold cycle, thereby improving the overall energy efficiency of the system.

[0013] Furthermore, between the energy storage and energy release phases, the control subsystem monitors the pressure and temperature parameters inside the flexible air storage bladder in real time. When abnormal parameters occur and reach alarm thresholds such as a pressure change rate ≥5% / min or a temperature ≥80℃, a fast switching valve is activated to introduce high-pressure air into the backup rigid air storage tank and close the inlet and outlet valves of the flexible air storage bladder.

[0014] Furthermore, through the aforementioned control subsystem, during the energy release phase, based on the grid frequency deviation... By dynamically adjusting the intake flow rate of the expansion generator system and combining short-time power prediction with multi-objective particle swarm optimization (MOPSO), the system can output the required power in a short time to meet the primary frequency regulation requirements of the power grid.

[0015] The beneficial effects of this invention are: 1. This invention adopts an underground flexible gas storage structure, combined with concrete lining and sliding layer, to enhance geological adaptability and reduce the risk of gas storage device leakage and construction cost.

[0016] 2. This invention achieves multi-stage heat recovery and closed-loop recycling, effectively improving the overall system efficiency.

[0017] 3. This invention introduces a short-time power prediction combined with a multi-objective particle swarm optimization (MOPSO) control strategy, providing complete and reproducible optimization steps to achieve short-time rapid response of the power grid's primary frequency regulation. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a compressed air energy storage system based on multi-stage heat recovery and underground flexible gas storage in an embodiment of the present invention.

[0019] Figure 2 This is a cross-sectional view of the underground flexible gas storage airbag structure of the present invention.

[0020] Figure 3 This is a flowchart of the control logic and multi-objective particle swarm optimization (MOPSO) process of the present invention.

[0021] The components are as follows: 1-Ambient air filter; 2a-2c-First to third stage air compressors; 3a-3c-First to third stage heat exchangers; 4-High temperature heat storage tank; 5-Low temperature cold storage tank; 6-Circulation pump; 7-Underground flexible air storage bladder; 8-Quick switching valve; 9-Spare rigid air storage tank; 10a-10c-First to third stage reheaters; 11a-11c-First to third stage expanders; 12-Generator; 13-Control unit; 14-Data acquisition sensor group; 15-External interface.

[0022] 7a-Concrete masonry layer; 7b-Slip layer; 7c-Outer protective layer; 7d-Aramid fiber reinforced layer; 7d-1-Circumferential reinforcing rib; 7d-2-Radial reinforcing rib; 7e-TPU inner sealing layer; 13a - Power prediction model; 13b - Multi-objective optimizer; 13c - Command execution output; 13d - Fault diagnosis and safety protection; 14 - Data acquisition sensors: frequency / pressure / temperature / flow, etc.; 15a - New energy prediction interface; 15b - Power grid dispatch interface. Detailed Implementation

[0023] To make the purpose, technical solution, and advantages of the invention clearer, the invention will be further described below with reference to the accompanying drawings.

[0024] Compressed air energy storage systems based on underground flexible gas storage, such as Figure 1As shown, the system includes a compression subsystem, a heat storage subsystem, a gas storage subsystem, an expansion and power generation subsystem, and a control subsystem, wherein: a) The compression subsystem includes multi-stage compressors 2a-2c connected in series, with each compressor outlet connected in sequence to a heat exchanger 3a-3c for recovering compression heat; b) The heat storage subsystem includes a high-temperature heat storage tank 4, a low-temperature cold storage tank 5, and a circulation pump 6. The high-temperature outlet of the heat exchangers 3a-3c is connected to the high-temperature heat storage tank 4, and the low-temperature outlet is connected to the low-temperature cold storage tank 5, forming a closed-loop heat cycle; c) The gas storage subsystem includes a flexible gas storage bladder 7 buried underground. The flexible gas storage bladder 7 is externally provided with a concrete lining layer and a sliding layer. The sliding layer is used to adapt to ground deformation and enhance the sealing of the gas storage bladder 7. The sliding layer is made of ultra-high molecular weight polyethylene sheet or modified HDPE sliding film with a shear modulus ≤10MPa and a thickness of 3mm~10mm; d) The expansion power generation system includes at least two turbine expanders 11a-11c connected in series and a generator 12. A reheater 10a-10c is installed before the inlet of each expander 11a-11c. The high-temperature side of the reheater 10a-10c is connected to the high-temperature heat storage tank 4, and the low-temperature side is connected to the low-temperature cold storage tank 5, so as to reheat the high-pressure air using the recovered compression heat. The output shaft of the expander is drivenly connected to the generator 12, and the output end of the generator 12 is connected to the power grid to realize power generation. e) Control subsystem, the control subsystem includes a control unit 13, a data acquisition sensor group 14, and external interfaces 15a and 15b, which are used to adjust the operating power and thermal cycle control of the compression subsystem and the expansion power generation system in real time.

[0025] The flexible composite gas storage airbag comprises a TPU inner sealing layer, an aramid fiber reinforcement layer, and an outer protective layer. These three layers are tightly bonded together from the inside out: the TPU inner sealing layer is located on the innermost side of the airbag and is in direct contact with high-pressure air. It is tightly bonded to the inner side of the aramid fiber reinforcement layer through a hot-melt bonding process to achieve gas sealing; the aramid fiber reinforcement layer is located in the middle layer and completely covers the outside of the TPU inner sealing layer, providing structural strength and pressure resistance for the airbag; the outer protective layer is located on the outermost side of the airbag and completely covers the outside of the aramid fiber reinforcement layer, providing wear resistance, resistance to ground penetration, and isolation protection. The design burst pressure of the gas storage bladder is ≥3.5 times the rated operating pressure. The rated operating pressure is the design pressure for long-term stable operation of the bladder under normal energy storage and release conditions. This safety redundancy is a common design standard in the high-pressure flexible gas storage container industry and is used to prevent the bladder from rupturing due to ground deformation, impact, and fatigue loads. It can be verified through water pressure burst test and long-term pressure resistance aging test. The bladder remains sealed and stable within a range of ±15% of ground stress variation, and the leakage rate meets the safety requirements of underground gas storage projects.

[0026] The concrete piling layer 7a is a rigid bearing shell, with its outer surface in close contact with the surrounding rock and its inner surface defining the installation space of the slip layer 7b. The slip layer 7b is a low-shear transition zone, with no anchor bars on its outer surface and the inner surface of the concrete piling layer 7a, allowing relative slippage. The inner surface of the slip layer 7b is connected to the flexible air storage bladder 7 by a point-to-line connection using HDPE anchoring strips, which adapts to ground deformation and does not restrict the axial expansion and contraction of the air bladder.

[0027] The flexible air-storage bladder 7 is a sealed pressure vessel, with its outer surface completely enclosed within the sliding layer 7b, and its inner surface in direct contact with high-pressure air. The circumferential reinforcing ribs 7d-1 and radial reinforcing ribs 7d-2 of the bladder are arranged along the inner wall of the sliding layer to enhance the structural strength.

[0028] The gas storage subsystem includes a backup rigid gas storage tank 9, which is connected in parallel with the flexible gas storage bladder 7 via a quick-switching valve 8 for emergency gas storage in abnormal conditions.

[0029] The heat exchanger adopts an aluminum-magnesium alloy brazed plate-fin structure, with fins in the high-temperature side channel to enhance heat transfer and ensure high recovery efficiency of compression heat.

[0030] The thermal management process is divided into: Heat recovery: The outlet temperatures of the heat transfer medium of the three-stage compressor 2a-2c are 180℃, 230℃ and 270℃ respectively. After being heated by heat exchangers 3a-3c, the temperature rises to 220-290℃ and is stored in the high-temperature heat storage tank 4; Heat utilization: The inlet air of the three-stage expander 11a-11c is heated step by step by reheaters 10a-10c. The inlet temperature is stabilized at around 220℃ to maintain a high expansion efficiency.

[0031] In the control subsystem, the control unit 13 incorporates a power prediction model and a multi-objective particle swarm optimization (MOPSO) model. The power prediction model employs a short-time series prediction model, including one or a combination of moving average prediction, LSTM simplified prediction, and grey prediction. The multi-objective optimization model uses multi-objective particle swarm optimization (MOPSO) with power generation efficiency, frequency regulation response speed, and safety as optimization objectives. The control logic uses grid frequency deviation. Closed-loop control, real-time acquisition of frequency deviation, and dynamic adjustment of expander intake flow rate achieve rapid response in a single frequency adjustment. The specific optimization steps of the multi-objective particle swarm optimization (MOPSO) method of this invention include: Step 1: Determine the optimization variables. The total intake air flow rate of the expander, the heat transfer medium flow rate of each stage of the reheater, and the compression / release power distribution rate are used as optimization variables.

[0032] Step 2: Construct a multi-objective function 1) Efficiency objective: Maximize the system cycle efficiency; 2) Response objective: Minimize the first frequency regulation response time; 3) Safety objective: Minimize the deviation of gas storage pressure / temperature from the rated value.

[0033] Step 3: Set the following constraints: pressure change rate < 5% / min; airbag temperature < 80℃; expander inlet temperature within the safe range; generator power within the rated range.

[0034] Step 4: Set the number of particles to 50-200, the number of iterations to 100-500, the inertia weight to 0.4-0.9, the cognitive acceleration coefficient c1=1.494, and the social acceleration coefficient c2=1.494; randomly generate the initial particle positions and velocities.

[0035] Step 5: Particle fitness calculation. Each particle is substituted into the objective function to calculate its fitness, determining if the constraints are met. Non-dominated solutions are retained, and the external archive is updated. Pareto dominance is used to determine particle quality. Non-dominated solutions are saved through the external archive, and globally guiding particles are selected based on crowding distance.

[0036] Step 6: Particle position and velocity update.

[0037] Step 7: Termination judgment: Stop if the maximum number of iterations has been reached or the external file has converged; otherwise, return to step 5 to continue iterating.

[0038] Step 8: Output the optimal control command to select the optimal solution, output the expander inlet flow rate, reheater flow rate, and power command, and drive the actuator to complete one frequency regulation.

[0039] The operation method of the compressed air energy storage system based on underground flexible gas storage includes the following steps: a) Energy storage stage: The compression subsystem is driven by off-peak electricity to compress ambient air to high pressure. The compression heat generated during the compression process is stored in the high-temperature heat storage tank 4 through heat exchangers 3a and 3c. The cooled high-pressure air is injected into the underground flexible gas storage bladder 7; b) Energy release stage: During peak grid load, the high-pressure air is released from the flexible gas storage bladder 7, and after absorbing the high-temperature heat storage heat through reheaters 10a-10c, it enters the expansion and power generation system to drive the expander to do work and drive the generator 12 to generate electricity, which is then fed into the grid; c) Heat recovery cycle stage: The heat storage subsystem realizes a closed-loop cycle of compression heat and expansion cold through a heat transfer medium to improve the overall energy efficiency of the system.

[0040] The control subsystem monitors the internal pressure and temperature of the flexible air storage bladder 7 in real time. When the pressure change rate is ≥5% / min or the temperature is ≥80℃, the quick switching valve 8 is activated to introduce high-pressure air into the backup rigid air storage tank 9 and close the inlet and outlet valves of the flexible air storage bladder 7.

[0041] The control subsystem, during the energy release phase, adjusts the power grid frequency deviation accordingly. The short-time power prediction model is activated, and multi-objective particle swarm optimization (MOPSO) is invoked to complete the optimal calculation. The expander intake flow is dynamically adjusted so that the system outputs the required power in the short term and meets the primary frequency regulation requirements of the power grid.

[0042] Finally, it should be noted that the contents not described in detail in this specification belong to the prior art known to those skilled in the art. The above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A compressed air energy storage system based on underground flexible gas storage, characterized in that, include: A compression subsystem, comprising at least two stages of compressors connected in series, with each stage compressor outlet connected in sequence to a heat exchanger for recovering compression heat; The thermal storage subsystem includes a high-temperature thermal storage tank, a low-temperature cold storage tank, and a circulating pump. The high-temperature side outlet of the heat exchanger is connected to the high-temperature thermal storage tank, and the low-temperature side outlet is connected to the low-temperature cold storage tank, forming a closed thermal cycle. The gas storage subsystem includes a flexible composite gas storage bladder buried underground. The gas storage bladder is provided with a concrete lining layer and a sliding layer on the outside. The sliding layer is used to adapt to the deformation of the strata and enhance the sealing performance of the gas storage bladder. An expansion generator system includes at least two stages of expanders and generators connected in series. A reheater is installed before the inlet of each expander. The high-temperature side of the reheater is connected to the high-temperature heat storage tank, and the low-temperature side outlet is connected to the low-temperature cold storage tank, so as to reheat the high-pressure air using the recovered compression heat. The output shaft of the expander is drivenly connected to the generator, and the output end of the generator is connected to the power grid. The control subsystem includes a data acquisition sensor group, a control unit, and an external interface, which is used to adjust the system operating parameters in real time and meet the primary frequency regulation requirements of the power grid.

2. The compressed air energy storage system based on underground flexible gas storage according to claim 1, characterized in that: The flexible composite material airbag includes a TPU inner sealing layer, an aramid fiber reinforcement layer, and an outer protective layer. The TPU inner sealing layer is located on the innermost side of the airbag and is in direct contact with high-pressure air. The aramid fiber reinforcement layer is located in the middle layer and is completely covered by the TPU inner sealing layer. The outer protective layer is located on the outermost side of the airbag and is completely covered by the aramid fiber reinforcement layer.

3. The compressed air energy storage system based on underground flexible gas storage according to claim 1, characterized in that: The gas storage subsystem further includes a backup rigid gas storage tank, which is connected in parallel with the flexible gas storage bladder via a quick-switching valve. When the pressure change rate is ≥5% / min or the temperature is ≥80℃, the control subsystem activates the quick-switching valve to enable the rigid gas storage tank and close the flexible gas storage bladder.

4. The compressed air energy storage system based on underground flexible gas storage according to claim 1, characterized in that: The heat exchanger adopts an aluminum-magnesium alloy brazed plate fin structure, and the inner wall of the high-temperature side channel is provided with a finned heat transfer enhancement structure.

5. The compressed air energy storage system based on underground flexible gas storage according to claim 1, characterized in that: The power prediction model adopts a short-time series prediction model, including one or a combination of moving average prediction, LSTM prediction, and grey prediction.

6. The compressed air energy storage system based on underground flexible gas storage according to claim 1, characterized in that: The control unit incorporates a power prediction model and a multi-objective particle swarm optimization (MOPSO) module. The MOPSO module is used to output optimal control commands to regulate the operation of the expander and reheater.

7. An operation method for a compressed air energy storage system based on underground flexible gas storage, characterized in that, Includes the following steps: Energy storage stage: The compression subsystem is driven by off-peak electricity to compress ambient air to high pressure. The heat of compression is stored in a high-temperature heat storage tank through a heat exchanger. The cooled high-pressure air is then injected into an underground flexible air storage bladder. Energy release phase: During peak grid load, high-pressure air is released from the flexible air storage bladder, reheated by the reheater, and then enters the expansion power generation system to generate electricity, which is then fed into the grid. Heat recovery cycle stage: The heat storage subsystem realizes a closed-loop cycle of compression heat and expansion cold, thereby improving system energy efficiency.

8. The operation method of the compressed air energy storage system based on underground flexible gas storage according to claim 7, characterized in that: The control subsystem monitors the internal pressure and temperature parameters of the flexible air storage bladder in real time. When the pressure change rate exceeds the preset value or the temperature exceeds the preset value, the quick switching valve is activated to introduce high-pressure air into the backup rigid air storage tank and close the flexible air storage bladder.

Images