Pressure self-balanced water steel double-sealed underground gas storage and operation method thereof

Abstract

The application discloses a pressure self-balancing water-steel double-sealing underground gas storage, and relates to the technical field of underground energy storage. The underground gas storage comprises a main body, a gas injection and extraction pipeline, a gas discharge pipeline and a gas injection and discharge water pipeline. The main body comprises, from outside to inside, a lining layer, a water sealing layer, a steel plate sealing layer and an inner chamber. The water sealing layer is communicated with the inner chamber through a pressure balance port. The gas injection and extraction pipeline is communicated with the inner chamber after penetrating the surrounding rock, the lining layer, the water sealing layer and the steel plate sealing layer in sequence. Compared with the conventional artificial chamber gas storage adopting a single-layer steel plate sealing or a steel plate composite sealing structure, the water-steel double-sealing underground gas storage adopts a double-layer sealing structure of the water sealing layer and the steel plate sealing layer, solves the problems of the overall failure of the gas storage or the increase of the leakage amount caused by the leakage of the steel plate sealing layer, and effectively improves the gas tightness of the gas storage. The application also relates to an operation method of the pressure self-balancing water-steel double-sealing underground gas storage.

Description

Technical Field

[0001] This invention relates to the field of underground energy storage technology, and more specifically to a pressure-balanced, water-steel double-sealed underground gas storage facility; this invention also relates to the operation method of such a pressure-balanced, water-steel double-sealed underground gas storage facility. Background Technology

[0002] Compressed air energy storage works by using a compressor to compress ambient air to a high-pressure state and storing it in an air storage tank during off-peak electricity demand periods or when renewable energy sources are generating a large amount of electricity. During peak electricity demand periods, the high-pressure air stored in the air storage tank is released and drives an expander to generate electricity. Compressed air energy storage is currently recognized as a large-capacity, ultra-long-duration energy storage technology comparable to pumped hydro storage. It can provide auxiliary services to the power grid such as peak shaving, frequency regulation, phase regulation, black start, and rotational inertia. In recent years, it has received widespread attention from scholars at home and abroad. Currently, several large-capacity compressed air energy storage projects in China have been completed and put into commercial operation or are under construction.

[0003] Compressed air energy storage storage facilities mainly include salt caverns, artificial chambers, abandoned mines, and surface pipeline steel. Among these, salt cavern resources are limited; surface pipeline steel is expensive, limiting its widespread application; abandoned mines are rich in resources and have great application potential, but their renovation costs are relatively high; artificial chambers are artificially excavated gas storage facilities in hard rock, which can basically overcome the limitations of geographical conditions and is a new type of gas storage method that improves the site selection flexibility of large-scale compressed air energy storage projects. In recent years, they have been applied in several engineering projects, but none of them have been put into formal operation yet.

[0004] Artificial chamber excavation or conversion of abandoned mines into energy storage and gas storage facilities must meet airtightness requirements. Currently, existing artificial chamber or abandoned mine gas storage technologies have the following problems: 1) In terms of sealing, existing conventional solutions mainly rely on steel plate sealing, with some using composite sealing of steel plate and flexible materials. Steel plate sealing or composite sealing is a single-layer sealing. When a local sealing failure occurs, it is very easy to cause the steel plate sealing in the entire gas storage to fail, which in turn leads to the failure of the gas storage or an increase in the leakage rate. 2) In terms of cost, the steel plate seal of conventional artificial chamber gas storage needs to withstand the high pressure inside the gas storage, so the thickness of the sealing steel plate is generally selected to be thicker. The overall steel plate welding work of the gas storage is large and the cost is expensive. 3) Regarding the effective utilization rate, in order to reduce the overall investment of the gas storage, the operating pressure range of the artificial chamber gas storage is generally selected to be above 4MPa. Therefore, the temperature fluctuation in the gas storage is large during the gas injection and extraction process. The increase in temperature in the gas storage during gas injection and the decrease in temperature in the gas storage during gas extraction will inevitably lead to a decrease in the effective utilization rate of the gas storage. Therefore, in order to meet a certain energy storage capacity, it is necessary to build a larger volume gas storage, which further increases the cost of the gas storage.

[0005] Therefore, it is necessary to develop a self-balancing water-steel double-sealed underground gas storage facility and its operation method that can effectively solve the problems of easy failure or high leakage rate of the seal of existing artificial chamber gas storage facilities, high overall cost caused by the large thickness of the sealing steel plate, alleviate the problem of reduced volume utilization rate caused by large temperature fluctuations in artificial chamber gas storage facilities, effectively improve the sealing performance of the gas storage facility, and ultimately reduce the pressure of the overall investment in the gas storage facility. Summary of the Invention The primary objective of this invention is to overcome the shortcomings of the aforementioned background technology and provide a pressure-balanced, water-and-steel double-sealed underground gas storage facility. This addresses the problem of high failure or leakage rates in existing artificial chamber gas storage facilities that rely on single-layer or composite steel plate seals, leading to easy seal failure. The double-sealed structure of water and steel plates ensures the airtightness of the gas storage facility, improving its safety and reliability. Furthermore, it addresses the issues of large steel plate thickness, extensive welding work, and high costs associated with single-layer or composite steel plate seals in existing artificial chamber gas storage facilities. The double-sealed structure effectively reduces the thickness of the steel plate seal layer, lowering the welding workload and overall investment. Finally, it mitigates temperature fluctuations in compressed air during injection and extraction in existing artificial chamber gas storage facilities, improving the space utilization rate, reducing excavation work, and lowering overall investment.

[0006] The second objective of this invention is to provide an operating method for this pressure-balanced, water-steel double-sealed underground gas storage facility.

[0007] To achieve the aforementioned first objective, the technical solution of the present invention is as follows: a pressure-balanced water-steel double-sealed underground gas storage facility, characterized in that: it includes an underground gas storage main body, gas injection and extraction pipelines, gas venting pipelines, and water injection and venting pipelines; the underground gas storage main body is located within the surrounding rock, and the underground gas storage main body is provided with, from the outside to the inside, a lining layer, a water-sealing layer, a steel plate sealing layer, and an inner chamber; The water seal layer is connected to the inner cavity through a pressure balance port; The gas injection and extraction pipeline of the gas storage facility passes through the surrounding rock, lining layer, water seal layer and steel plate seal layer in sequence before connecting to the inner cavity. The gas storage venting pipeline passes through the surrounding rock and lining layer in sequence before connecting to the water seal layer. The gas storage tank's water injection and discharge pipelines pass through the surrounding rock and lining layer in sequence before connecting to the water seal layer.

[0008] In the above technical solution, the steel plate sealing layer adopts a cylindrical structure, and multiple rigid rings are evenly spaced along the axial direction on the outer side of the steel plate sealing layer; multiple support seats are spaced on the lower half of the outer side of the rigid rings, and the support seats are connected to the lining layer through anchor plates; the anchor plates are located inside the lining layer and are connected to the surrounding rock through anchor rods.

[0009] In the above technical solution, the inner side of the anchor plate is flush with the inner side of the lining layer.

[0010] In the above technical solution, the pressure balance port is located at the lowest point of the bottom of the steel plate sealing layer; the gas injection and extraction pipeline of the gas storage tank is connected to the top of the inner chamber; the gas venting pipeline of the gas storage tank is connected to the highest point of the water sealing layer; and the water injection and drainage pipeline of the gas storage tank is connected to the lowest point of the water sealing layer.

[0011] In the above technical solution, a water level monitor is installed on one side of the pressure balance port inside the inner cavity; In the above technical solution, a gas-side shut-off valve is installed on the gas injection and extraction pipeline of the gas storage facility; a venting valve is installed on the gas venting pipeline of the gas storage facility; and a water-side shut-off valve is installed on the water injection and drainage pipeline of the gas storage facility.

[0012] In the above technical solution, fins are spaced apart on the inner side of the steel plate sealing layer; the water-side shut-off valve is connected to the water injection system and the forced circulation system respectively; the forced circulation system includes a circulation pump connected to the water-side shut-off valve; the circulation pump is connected to a heat exchanger, and the heat exchanger is connected to the gas injection and extraction pipeline of the gas storage tank, with the connection point located on the gas injection and extraction pipeline of the gas storage tank between the outer side of the lining layer and the gas-side shut-off valve.

[0013] To achieve the second objective mentioned above, the technical solution of the present invention is: an operation method for a pressure-balanced, water-steel double-sealed underground gas storage facility, characterized by comprising the following steps: Step 1, Water injection before initial gas storage: Open the water-side shut-off valve on the gas storage water injection pipeline and the gas release valve on the gas storage gas release pipeline; start the ground system's water injection system, and inject water into the bottom of the water seal layer through the gas storage water injection pipeline until the water level submerges the upper part of the pressure balance port. Open the gas-side shut-off valve on the gas injection and extraction pipeline of the gas storage facility, start the gas injection system of the ground system, and inject compressed air into the inner chamber through the gas injection and extraction pipeline of the gas storage facility; run the gas injection system and water injection system simultaneously, and maintain the water level above the pressure balance port; as the gas-side pressure in the inner chamber increases, the injected water is gradually filled into the entire water seal layer by the pressure of the air in the inner chamber; after water flows out of the gas storage facility vent pipeline, it indicates that the water seal layer is full of water, close the vent valve and the water-side shut-off valve, and complete the water injection process before the first gas storage. Step 2, Gas storage in the gas storage facility: Keep the gas-side shut-off valve open and continue operating the gas injection system on the ground system to continuously inject air into the inner chamber, causing the pressure inside the inner chamber to rise continuously. At the same time, since the water in the water seal layer is connected to the gas side of the inner chamber through the pressure balance port, the water-side pressure of the water seal layer also rises continuously along with the gas-side pressure. Therefore, the pressure inside and outside the steel plate seal layer is basically balanced, and it always only bears the static internal pressure generated by the gravity of the water at the vertical height of the water seal layer. Continue injecting gas until the pressure inside the inner chamber reaches the upper limit of the design pressure range, then stop injecting gas, close the gas-side shut-off valve, and complete the gas storage process of the gas storage tank. Step 3, Gas extraction from the gas storage facility: Open the gas-side shut-off valve, and the high-pressure air in the inner chamber is connected to the ground system through the gas injection and extraction pipeline of the gas storage facility. It then enters the ground system to expand and generate electricity. During the gas extraction process, the water-side pressure in the water seal layer decreases as the gas-side pressure in the inner chamber decreases, and the pressure inside and outside the steel plate seal layer always remains basically balanced. Continue gas extraction until the pressure inside the inner chamber drops to the lower limit of the design pressure range, then stop gas extraction, close the gas-side shut-off valve, and complete the gas extraction process of the gas storage facility. Step 4: Repeat steps 2-3 to complete the cycle of gas storage and gas extraction processes in the gas storage facility.

[0014] In the above technical solution, in step 2, the heat exchanger of the forced circulation system is turned on, and the heat exchanger cools the water in the water seal layer. The water in the water seal layer is provided with fins at intervals on the inner side of the steel plate seal layer, and the water in the water seal layer cools the air in the inner cavity, thereby alleviating the temperature rise on the gas side during gas injection. In step 3, the heat exchanger of the forced circulation system is turned on. The heat exchanger heats the water in the water seal layer. In conjunction with the fins spaced on the inner side of the steel plate seal layer, the water in the water seal layer heats the air in the inner chamber, thereby alleviating the temperature drop on the gas side during gas sampling.

[0015] In the above technical solution, the maintenance of the gas storage facility includes normal water discharge maintenance and water seal layer operation leakage maintenance. Normal water drainage maintenance includes the following steps: Open the gas-side shut-off valve to release the gas-side pressure in the inner chamber to near the static pressure generated by the highest water level in the water seal layer; at the same time, open the water-side shut-off valve to release the water in the water seal layer to the ground system to prevent water from entering the inner chamber. Alternatively, open the air-side shut-off valve to release the air-side pressure in the inner chamber to atmospheric pressure, allowing water from the water seal layer to enter the air-side space of the inner chamber. Then, open the water-side shut-off valve to release the water in the inner chamber to the ground system. Maintenance work can begin once the water has been drained. Leakage maintenance during water seal operation includes the following steps: A water level monitor at the pressure balance port is used to monitor whether leakage occurs in the water seal during operation; When the water level monitor detects that the water level in the inner chamber exceeds the set lower limit, it indicates that the water seal layer is leaking outwards. At this time, open the water-side shut-off valve, start the water injection system, and replenish water to the water seal layer in time to ensure that the water level in the inner chamber is always above the set lower limit. When the water level monitor detects that the water level in the inner chamber exceeds the set upper limit, it indicates that the water seal layer has leaked inward or there is too much condensation in the air inside the inner chamber. At this time, the water-side shut-off valve is opened to discharge the excess water to the ground system through the gas storage tank water injection pipeline in a timely manner, ensuring that the water level in the inner chamber is always below the set upper limit.

[0016] Compared with the prior art, the present invention has the following advantages.

[0017] 1) Compared with conventional artificial chamber gas storage facilities that use a single-layer or composite steel plate sealing structure, this invention solves the problem of overall gas storage failure or increased leakage caused by leakage of the steel plate sealing layer by setting a double-layer sealing structure of water sealing layer and steel plate sealing layer, effectively improving the airtightness of the gas storage facility.

[0018] 2) Compared with conventional artificial chamber gas storage facilities that use thick steel plate structures for single-layer or composite steel plate sealing, this invention ensures that the pressure on the inner and outer sides of the steel plate sealing layer remains basically balanced through the setting of pressure balance ports. The steel plate sealing layer always bears only a very small internal pressure, and the steel plate sealing layer can be made of thin steel plate. According to calculations, the thickness can be controlled to be below 10mm, which effectively reduces the thickness of the steel plate sealing layer, reduces the amount of welding work for the steel plate sealing layer, and reduces the overall investment of the gas storage facility.

[0019] 3) Compared with conventional artificial chamber gas storage facilities, this invention utilizes the self-cooling / heating function of the water-sealed layer. The water-sealed layer helps to mitigate temperature fluctuations of compressed air within the gas storage facility. During gas injection, as the temperature inside the gas storage facility rises, the water in the water-sealed layer cools the facility, preventing excessive temperature increases. During gas extraction, as the temperature inside the gas storage facility decreases, the water in the water-sealed layer heats the facility, preventing excessive temperature drops. This effectively reduces the temperature fluctuation range during gas injection and extraction, improves the utilization rate of the gas storage facility, and lowers investment costs.

[0020] 4) The outer side of the steel plate sealing layer of this invention adopts a combined anti-corrosion scheme of paint and other coatings + sacrificial anode cathodic protection, while the inner side adopts an anti-corrosion scheme of paint and other coatings, which ensures the corrosion resistance of the steel plate sealing layer and improves the service life of the gas storage tank.

[0021] 5) This invention adopts a double-layer sealing structure of water seal + steel plate seal. The lining layer does not come into direct contact with compressed air, which effectively avoids the problem of the steel plate sealing layer falling off as a whole after compressed air leakage in conventional gas storage solutions, and improves the sealing effectiveness of the gas storage.

[0022] 6) In order to further reduce the temperature fluctuation range of the gas side during the gas injection and production process, improve the effective utilization rate of the gas storage facility, and reduce the investment in the gas storage facility, the present invention provides needle-shaped fins or other types of fins on the inner side of the steel plate sealing layer to improve the heat transfer coefficient of the gas side; and provides a forced circulation system on the water side to force cooling to alleviate the temperature rise of the gas side during gas injection and to force heating to alleviate the temperature drop of the gas side during gas production. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the present invention.

[0024] Figure 2 This is a longitudinal cross-sectional view of the main body of the gas storage facility.

[0025] Figure 3 This is a schematic diagram of the steel plate sealing layer.

[0026] Figure 4 This is an axial cross-sectional view of the main body of the gas storage facility when it is ring-shaped.

[0027] Figure 5 This is an axial cross-sectional view of the main body of the gas storage facility when the main body is strip-shaped.

[0028] Figure 6 This is a schematic diagram of a forced circulation system.

[0029] Among them, 100-underground gas storage main body, 110-lining layer, 120-water seal layer, 121-pressure balance port, 1211-water level monitor, 130-steel plate seal layer, 131-rigid ring, 132-support base, 133-anchor plate, 134-fin, 140-inner chamber, 200-gas storage injection and extraction pipeline, 210-gas side shut-off valve, 300-gas storage venting pipeline, 310-venting valve, 400-gas storage water injection and venting pipeline, 410-water side shut-off valve, 500-forced circulation system, 510-circulation pump, 520-heat exchanger. Detailed Implementation

[0030] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but these descriptions are not intended to limit the invention and are merely illustrative. The advantages of the present invention will become clearer and easier to understand through this description.

[0031] Referring to the attached drawings: A pressure-balanced water-steel double-sealed underground gas storage facility is characterized by comprising an underground gas storage body 100, gas injection and extraction pipelines 200, gas venting pipelines 300, and water injection and venting pipelines 400; the underground gas storage body 100 is located within the surrounding rock, and the underground gas storage body 100 is provided with, from the outside to the inside, a lining layer 110, a water-sealing layer 120, a steel plate sealing layer 130, and an inner chamber 140; The water seal layer 120 is formed by filling the cavity between the lining layer 110 and the steel plate seal layer 130 with water; The water seal layer 120 is connected to the inner chamber 140 through the pressure balance port 121; The gas storage injection and extraction pipeline 200 passes through the surrounding rock, lining layer 110, water seal layer 120 and steel plate seal layer 130 in sequence and then connects to the inner chamber 140; the gas storage injection and extraction pipeline 200 connects the underground gas storage main body 100 with the surface injection and extraction system. One end of the gas storage venting pipeline 300 passes through the surrounding rock and the lining layer 110 in sequence and then connects to the water seal layer 120, while the other end is connected to the environment. One end of the gas storage tank water injection / discharge pipeline 400 passes through the surrounding rock and lining layer 110 in sequence and then connects to the water seal layer 120, while the other end is connected to the external water injection / discharge system.

[0032] The steel plate sealing layer 130 adopts a cylindrical structure, and multiple rigid rings 131 are evenly spaced along the axial direction on the outer side of the steel plate sealing layer 130; multiple support seats 132 are spaced on the lower half of the outer side of the rigid rings 131, and the support seats 132 are connected to the lining layer 110 through anchor plates 133; the anchor plates 133 are located inside the lining layer 110, and the anchor plates 133 are connected to the surrounding rock through anchor rods.

[0033] The steel plate sealing layer is arranged horizontally in a 130mm configuration. It is made of thin steel plates welded together to form a cavity, and the whole structure is arranged in a ring shape or in a strip shape with end caps. The rigid ring 131 is made of channel steel or I-beam steel, and is evenly distributed around the steel plate sealing layer 130 along the axial direction of the cavity of the steel plate sealing layer 130. It is welded to the steel plate sealing layer 130 to improve the strength and stability of the steel plate sealing layer 130. Anchor plate 133 is fixed to the surrounding rock of the main body 100 of the gas storage tank by anchor rods. It is used to fix the steel plate sealing layer 130 and bear the weight of the steel plate sealing layer 130 and the upward tension during normal operation. The support seat 132 is used to connect the anchor plate 133 and the rigid ring 131. On the one hand, it is used to support and fix the steel plate sealing layer 130, and on the other hand, it transmits the weight of the steel plate sealing layer 130 itself and the upward tension during operation to the anchor plate 133. The inner side of the anchor plate 133 is flush with the inner side of the lining layer 110.

[0034] The pressure balance port 121 is located at the lowest point of the bottom of the steel plate sealing layer 130; the gas injection and extraction pipeline 200 of the gas storage tank is connected to the top of the inner chamber 140; the gas venting pipeline 300 of the gas storage tank is connected to the highest point of the water sealing layer 120; and the water injection and venting pipeline 400 of the gas storage tank is connected to the lowest point of the water sealing layer 120. When the main body 100 of the gas storage tank is in operation, the pressure balance port 121 transmits the gas-side pressure to the water seal layer 120, which plays a role in pressure balance.

[0035] A water level monitor 1211 is installed on one side of the pressure balance port 121 inside the inner chamber 140; A gas-side shut-off valve 210 is installed on the gas injection and extraction pipeline 200 of the gas storage facility to isolate the underground gas storage main body 100 from the ground system. The gas storage venting pipeline 300 is equipped with a venting valve 310, which is used to isolate the water seal layer 120 of the underground gas storage body 100 from the ambient atmosphere. When gas is released from the water seal layer 120 or a small amount of compressed air leaks into the water seal layer 120, it also has an automatic venting function. A water-side shut-off valve 410 is installed on the gas storage water injection / discharge pipeline 400 to isolate the water seal layer 120 of the underground gas storage body 100 from the ground water injection / discharge system.

[0036] To further reduce the temperature fluctuation range on the gas side during gas injection and production, improve the effective utilization rate of the gas storage facility, and reduce investment in the gas storage facility, fins 134 are spaced apart on the inner side of the steel plate sealing layer 130; the water-side shut-off valve 410 is connected to the water injection system and the forced circulation system 500 respectively; the forced circulation system 500 includes a circulation pump 510 connected to the water-side shut-off valve 410; the circulation pump 510 is connected to the heat exchanger 520, and the heat exchanger 520 is connected to the gas storage facility venting pipeline 300, with the connection point located on the gas storage facility venting pipeline 300 between the outer side of the lining layer 110 and the venting valve 310.

[0037] A method for operating a pressure-balanced, water-steel double-sealed underground gas storage facility, characterized by the following steps: Step 1, Water injection before initial gas storage: Open the water-side shut-off valve 410 on the gas storage water injection / discharge pipeline 400 and the vent valve 310 on the gas storage vent pipeline 300; start the ground system's water injection system, inject water into the bottom of the water seal layer 120 through the gas storage water injection / discharge pipeline 400 until the water level submerges the upper part of the pressure balance port 121; Open the gas-side shut-off valve 210 on the gas injection pipeline 200 of the gas storage facility, start the gas injection system of the ground system, and inject compressed air into the inner chamber 140 through the gas injection pipeline 200 of the gas storage facility; run the gas injection system and the water injection system simultaneously, and maintain the water level above the pressure balance port 121; as the gas-side pressure in the inner chamber 140 increases, the injected water is gradually filled into the entire water seal layer 120 by the pressure of the air in the inner chamber 140; after water flows out of the gas storage vent pipeline 300, it indicates that the water seal layer 120 is full of water, close the vent valve 310 and the water-side shut-off valve 410, and complete the water injection process before the first gas storage. Step 2, Gas storage in the gas storage tank: Keep the gas-side shut-off valve 210 open, and the ground system's gas injection system continues to operate, continuously injecting air into the inner chamber 140, causing the pressure inside the inner chamber 140 to rise continuously. At the same time, since the water in the water seal layer 120 is connected to the gas side of the inner chamber 140 through the pressure balance port 121, the water-side pressure of the water seal layer 120 also rises continuously along with the gas-side pressure. Therefore, the pressure inside and outside the steel plate sealing layer 130 is basically balanced (the inner side bears the air pressure, and the outer side bears the water pressure), and it always only bears the static internal pressure generated by the gravity of the water at the vertical height of the water seal layer 120. Continue injecting gas until the pressure inside the inner chamber 140 reaches the upper limit of the design pressure range, then stop injecting gas, close the gas-side shut-off valve 210, and complete the gas storage process of the gas storage tank. Step 3, Gas extraction from the gas storage facility: Open the gas-side shut-off valve 210, and the high-pressure air in the inner chamber 140 is connected to the ground system through the gas injection and extraction pipeline 200 of the gas storage facility, and enters the ground system to expand and generate electricity; during the gas extraction process, the water-side pressure in the water-sealing layer 120 decreases as the gas-side pressure in the inner chamber 140 decreases, and the pressure inside and outside the steel plate sealing layer 130 always remains basically balanced; Continue gas extraction until the pressure inside the inner chamber 140 drops to the lower limit of the design pressure range, then stop gas extraction, close the gas-side shut-off valve 210, and complete the gas extraction process of the gas storage facility. Step 4: Repeat steps 2-3 to complete the cycle of gas storage and gas extraction processes in the gas storage facility.

[0038] To further reduce the temperature fluctuation range on the gas side during gas injection and production, improve the effective utilization rate of the gas storage facility, and reduce the investment in the gas storage facility, in step 2, the heat exchanger 520 of the forced circulation system 500 is turned on. The heat exchanger 520 cools the water in the water seal layer 120. In conjunction with the fins 134 spaced on the inner side of the steel plate seal layer 130, the water in the water seal layer 120 forcibly cools the air in the inner chamber 140, thereby alleviating the temperature rise on the gas side during gas injection. In step 3, the heat exchanger 520 of the forced circulation system 500 is turned on. The heat exchanger 520 heats the water in the water seal layer 120. In conjunction with the fins 134 spaced apart on the inner side of the steel plate seal layer 130, the water in the water seal layer 120 forcibly heats the air in the inner chamber 140, thereby alleviating the temperature drop on the gas side during gas extraction.

[0039] Gas storage facility maintenance includes routine water discharge maintenance and water seal layer leakage maintenance. Normal water discharge maintenance includes the following steps: open the gas-side shut-off valve 210 to release the gas-side pressure of the inner chamber 140 to near the static pressure generated by the highest water level of the water seal layer 120; at the same time, open the water-side shut-off valve 410 to release the water in the water seal layer 120 to the ground system to prevent water from entering the inner chamber 140. Alternatively, open the gas-side shut-off valve 210 to release the gas-side pressure of the inner chamber 140 to atmospheric pressure, allowing water in the water seal layer 120 to enter the gas-side space of the inner chamber 140, and then open the water-side shut-off valve 410 to release the water in the inner chamber 140 to the ground system. Maintenance work can begin once the water has been drained. Leakage maintenance of the water seal layer includes the following steps: The water level monitor 1211 at the pressure balance port 121 is used to monitor whether leakage occurs in the water seal layer 120 during operation; When the water level monitor 1211 detects that the water level in the inner chamber 140 exceeds the set lower limit, it indicates that the water seal layer 120 has leaked outward; at this time, the water-side shut-off valve 410 is opened, the water injection system is started, and water is replenished to the water seal layer 120 in time to ensure that the water level in the inner chamber 140 is always above the set lower limit. When the water level monitor 1211 detects that the water level in the inner chamber 140 exceeds the set upper limit, it indicates that water has seeped into the water seal layer 120 or there is too much condensation in the air inside the inner chamber 140. At this time, the water-side shut-off valve 410 is opened to discharge the excess water to the ground system in a timely manner through the gas storage water discharge pipeline 400, ensuring that the water level in the inner chamber 140 is always below the set upper limit.

[0040] In practical use, when the surrounding rock of the main body 100 of the gas storage facility has good lithology, the lining layer 110 can be made of concrete or reinforced concrete; when the surrounding rock of the main body 100 of the gas storage facility has poor lithology, the lining layer 110 can be made of reinforced concrete lining + grouting structure to ensure the water tightness of the lining layer 110.

[0041] During the gas injection and extraction process, the pressure inside and outside the steel plate sealing layer 130 remains balanced, bearing only a certain internal pressure (the internal pressure is equal to the static pressure generated by the highest water level of the water sealing layer 120). Furthermore, the sealing of the main body 100 of the gas storage is achieved through the steel plate sealing layer 130 and the water sealing layer 120. Therefore, the steel plate sealing layer 130 does not need to be as thick as the steel plate sealing layer of a conventional artificial chamber gas storage, which can effectively save steel consumption, reduce the amount of steel plate welding work, and reduce the overall cost of the gas storage.

[0042] The outer side of the steel plate sealing layer 130 adopts a combined anti-corrosion scheme of paint and other coatings plus sacrificial anode cathodic protection, while the inner side adopts an anti-corrosion scheme of paint and other coatings, which ensures the corrosion resistance of the steel plate sealing layer 130 and improves the service life of the gas storage facility.

[0043] All other unspecified parts belong to the prior art.

Claims

1. A pressure-balanced, water-steel double-sealed underground gas storage tank, characterized in that: It includes an underground gas storage main body (100), gas injection and extraction pipelines (200), gas venting pipelines (300), and water injection and drainage pipelines (400); the underground gas storage main body (100) is located within the surrounding rock, and the underground gas storage main body (100) is provided with a lining layer (110), a water sealing layer (120), a steel plate sealing layer (130), and an inner chamber (140) from the outside to the inside; The water seal layer (120) is connected to the inner chamber (140) through the pressure balance port (121); The gas injection and extraction pipeline (200) of the gas storage facility passes through the surrounding rock, lining layer (110), water seal layer (120) and steel plate seal layer (130) in sequence and then connects to the inner chamber (140); The gas storage venting pipeline (300) passes through the surrounding rock and the lining layer (110) in sequence and then connects to the water seal layer (120); The gas storage tank water injection and discharge pipeline (400) passes through the surrounding rock and the lining layer (110) in sequence and then connects to the water seal layer (120).

2. The pressure-balanced water-steel double-sealed underground gas storage tank according to claim 1, characterized in that: The steel plate sealing layer (130) adopts a cylindrical structure. Multiple rigid rings (131) are evenly spaced along the axial direction on the outer side of the steel plate sealing layer (130). Multiple support seats (132) are spaced on the lower half of the outer side of the rigid rings (131). The support seats (132) are connected to the lining layer (110) through anchor plates (133). The anchor plates (133) are located inside the lining layer (110) and are connected to the surrounding rock through anchor rods.

3. The pressure-self-balancing water-steel double-sealed underground gas storage tank according to claim 2, characterized in that: The inner side of the anchor plate (133) is flush with the inner side of the lining layer (110).

4. The pressure-balanced water-steel double-sealed underground gas storage tank according to claim 2, characterized in that: The pressure balance port (121) is located at the lowest point of the bottom of the steel plate sealing layer (130); the gas injection and extraction pipeline (200) of the gas storage tank is connected to the top of the inner chamber (140); the gas venting pipeline (300) of the gas storage tank is connected to the highest point of the water sealing layer (120); the water injection and drainage pipeline (400) of the gas storage tank is connected to the lowest point of the water sealing layer (120).

5. The pressure-self-balancing water-steel double-sealed underground gas storage tank according to claim 4, characterized in that: The pressure balance port (121) is located on one side of the inner chamber (140) and a water level monitor (1211) is installed.

6. The pressure-balanced water-steel double-sealed underground gas storage tank according to claim 1, characterized in that: A gas-side shut-off valve (210) is installed on the gas injection and extraction pipeline (200) of the gas storage facility; a venting valve (310) is installed on the gas venting pipeline (300) of the gas storage facility; and a water-side shut-off valve (410) is installed on the water injection and venting pipeline (400) of the gas storage facility.

7. The pressure-self-balancing water-steel double-sealed underground gas storage tank according to claim 6, characterized in that: The inner side of the steel plate sealing layer (130) is provided with fins (134) at intervals; the water-side shut-off valve (410) is connected to the water injection system and the forced circulation system (500) respectively; the forced circulation system (500) includes a circulation pump (510) connected to the water-side shut-off valve (410); the circulation pump (510) is connected to the heat exchanger (520), the heat exchanger (520) is connected to the gas storage venting pipeline (300), and the connection point is located on the gas storage venting pipeline (300) between the outer side of the lining layer (110) and the venting valve (310).

8. A method for operating a pressure-balanced, water-steel double-sealed underground gas storage facility, characterized in that, Includes the following steps: Step 1, Water injection before first gas storage: Open the water-side shut-off valve (410) on the gas storage water injection / discharge pipeline (400) and the gas release valve (310) on the gas storage gas release pipeline (300); start the ground system's water injection system, and inject water into the bottom of the water seal layer (120) through the gas storage water injection / discharge pipeline (400) until the water level submerges the upper part of the pressure balance port (121); Open the gas-side shut-off valve (210) on the gas injection pipeline (200) of the gas storage facility, start the gas injection system of the ground system, and inject compressed air into the inner chamber (140) through the gas injection pipeline (200) of the gas storage facility; run the gas injection system and the water injection system simultaneously, and maintain the water level above the pressure balance port (121); as the gas-side pressure in the inner chamber (140) increases, the injected water is gradually filled into the entire water seal layer (120) by the air pressure in the inner chamber (140); after water flows out of the gas venting pipeline (300) of the gas storage facility, it indicates that the water seal layer (120) is full of water, close the venting valve (310) and the water-side shut-off valve (410) to complete the water injection process before the first gas storage; Step 2, gas storage in the gas storage tank: Keep the gas-side shut-off valve (210) open, and the gas injection system of the ground system continues to operate, continuously injecting air into the inner chamber (140), and the pressure in the inner chamber (140) continues to rise; at the same time, since the water in the water seal layer (120) is connected to the gas side in the inner chamber (140) through the pressure balance port (121), the water side pressure of the water seal layer (120) also rises continuously with the gas side pressure. Therefore, the pressure inside and outside the steel plate seal layer (130) is basically balanced, and it always only bears the static internal pressure generated by the gravity of the water in the vertical height of the water seal layer (120); Continue injecting gas until the pressure in the inner chamber (140) reaches the upper limit of the design pressure range, then stop injecting gas, close the gas-side shut-off valve (210), and complete the gas storage process of the gas storage tank. Step 3, Gas extraction from the gas storage: Open the gas-side shut-off valve (210), and the high-pressure air in the inner chamber (140) is connected to the ground system through the gas injection and extraction pipeline (200) of the gas storage, and enters the ground system to expand and generate electricity; During the gas extraction process, the water-side pressure in the water seal layer (120) decreases as the gas-side pressure in the inner chamber (140) decreases, and the pressure inside and outside the steel plate seal layer (130) always remains basically balanced; Continue gas extraction until the pressure in the inner chamber (140) drops to the lower limit of the design pressure range, then stop gas extraction, close the gas-side shut-off valve (210), and complete the gas extraction process of the gas storage facility. Step 4: Repeat steps 2-3 to complete the cycle of gas storage and gas extraction processes in the gas storage facility.

9. The operation method of a pressure-balanced water-steel double-sealed underground gas storage facility according to claim 8, characterized in that, In step 2, the heat exchanger (520) of the forced circulation system (500) is turned on. Fins (134) are spaced apart on the inner side of the steel plate sealing layer (130). The heat exchanger (520) cools the water in the water sealing layer (120). The water in the water sealing layer (120) cools the air in the inner chamber (140), thereby alleviating the temperature rise on the gas side during gas injection. In step 3, the heat exchanger (520) of the forced circulation system (500) is turned on. In step 3, the heat exchanger of the forced circulation system is turned on. Fins (134) are arranged at intervals on the inner side of the steel plate sealing layer (130). The heat exchanger (520) heats the water in the water sealing layer (120). The water in the water sealing layer (120) heats the air in the inner chamber (140), thereby alleviating the temperature drop on the gas side during gas collection.

10. The operation method of a pressure-balanced water-steel double-sealed underground gas storage facility according to claim 8, characterized in that, Gas storage facility maintenance includes routine water discharge maintenance and water seal layer leakage maintenance. Normal water discharge maintenance includes the following steps: open the gas-side shut-off valve (210) to release the gas-side pressure of the inner chamber (140) to near the static pressure generated by the highest water level of the water seal layer (120); at the same time, open the water-side shut-off valve (410) to release the water in the water seal layer (120) to the ground system to prevent water from entering the inner chamber (140); Alternatively, open the gas-side shut-off valve (210) to release the gas-side pressure of the inner chamber (140) to atmospheric pressure, allowing water in the water seal layer (120) to enter the gas-side space of the inner chamber (140), and then open the water-side shut-off valve (410) to release the water in the inner chamber (140) to the ground system. Maintenance work can begin once the water has been drained. Leakage maintenance of the water seal layer includes the following steps: a water level monitor (1211) at the pressure balance port (121) is used to monitor whether leakage occurs in the water seal layer (120) during operation; When the water level monitor (1211) detects that the water level in the inner chamber (140) exceeds the set lower limit, it indicates that the water seal layer (120) has leaked outward; at this time, the water-side shut-off valve (410) is opened, the water injection system is started, and water is replenished to the water seal layer (120) in time to ensure that the water level in the inner chamber (140) is always above the set lower limit; When the water level monitor (1211) detects that the water level in the inner chamber (140) exceeds the set upper limit, it indicates that water has seeped into the water seal layer (120) or there is too much condensation in the air inside the inner chamber (140). At this time, the water-side shut-off valve (410) is opened to discharge the excess water to the ground system in a timely manner through the gas storage water discharge pipeline (400) to ensure that the water level in the inner chamber (140) is always below the set upper limit.

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