Self-leveling pressure underground constant-volume gas storage structure and construction method

Abstract

The application discloses a self-pressure-equalizing underground constant-volume gas storage structure and a construction method, and belongs to the technical field of energy storage power station gas storage technology. The self-pressure-equalizing underground constant-volume gas storage structure comprises a gas storage bin, and the inner wall of the gas storage bin is sequentially provided with a sealing layer, a concrete lining layer and a surrounding rock layer from inside to outside. The gas storage bin is provided with a gas pipe for gas inlet and outlet. A pressure adjusting part is arranged in the gas storage bin, and the pressure adjusting part can self-adaptively adjust the pressure according to the real-time pressure in the gas storage bin. The inner and outer pressures of the sealing layer are balanced and synchronized, fatigue damage of the sealing layer under cyclic high and low pressure is avoided, the sealing performance is improved, and the service life is prolonged.

Description

Technical Field

[0001] This invention relates to the field of gas storage technology for energy storage power stations, and in particular to a self-leveling underground constant-volume gas storage structure and construction method. Background Technology

[0002] Currently, the structure of a fixed-volume underground artificial gas storage facility for compressed air energy storage power stations typically adopts the "sealing layer-concrete lining-surrounding rock" type. The sealing layer is used to ensure airtightness, bear part of the pressure, and transmit gas pressure. The concrete lining bears part of the pressure and transmits pressure, while the surrounding rock is the main pressure-bearing body.

[0003] To accommodate the operating pressure requirements of the turbine expander and reduce the storage volume of the gas storage tank, thereby lowering project investment, the minimum operating pressure of the fixed-volume underground gas storage tank in a compressed air energy storage power station is typically 6 MPa, while the maximum operating pressure can reach 18 MPa. The operating pressure range is wide, and high-low pressure cycles occur during operation. During the filling and discharging process, there is a gas expansion-compression cycle, and high-low temperature cycles occur within the gas storage tank.

[0004] Due to the small size of gas molecules, the sealing layer material of gas storage facilities must possess excellent airtightness to minimize gas leakage. Currently, sealing layer materials for artificial underground gas storage facilities mainly fall into two categories: rigid sealing materials, represented by steel plates, and flexible sealing materials, represented by rubber. Steel plate sealing layers offer excellent airtightness, crack resistance, and fatigue resistance, making them the preferred material for sealing layers in artificial underground gas storage facilities. However, steel plates have a higher elastic modulus than concrete and surrounding rock, requiring them to withstand significant pressure. Furthermore, the thickness of steel plates is substantial, resulting in high costs. Flexible sealing materials such as rubber offer advantages such as high flexibility, low cost, ease of construction, and corrosion resistance. However, they suffer from the disadvantage of being prone to sinkhole failure after cracking of the outer concrete lining.

[0005] The existing "sealing layer-concrete lining-surrounding rock" structure places the sealing layer in an environment with large fluctuations in high and low pressure and high and low temperature cycles. Rigid sealing materials such as steel plates have a larger elastic modulus than concrete and surrounding rock and need to withstand greater internal pressure. Flexible sealing materials such as rubber will experience cracking and deformation after the outer concrete lining, which provides support, cracks. Therefore, both rigid and flexible sealing layers are prone to fatigue damage, which increases the risk of gas leakage. Summary of the Invention

[0006] To overcome its shortcomings, the technical problem to be solved by this invention is: how to improve the problem of fatigue damage that easily occurs in the sealing layer of existing gas storage tanks.

[0007] The technical solution adopted by this invention to solve its technical problem is: The self-leveling underground constant-volume gas storage structure includes a gas storage chamber. The inner wall of the gas storage chamber is sequentially arranged with a sealing layer, a concrete lining layer, and a surrounding rock layer from the inside out. The gas storage chamber is equipped with gas pipes for air intake and exhaust. A pressure regulating component is installed inside the gas storage chamber, which can adaptively adjust the pressure according to the real-time pressure inside the gas storage chamber. The pressure regulating component includes a pressure bladder. The sealing layer includes an air-tight layer and a sealing layer sequentially arranged from the inside out. The outer side of the sealing layer is connected to the concrete lining layer. Multiple connecting ribs are provided between the air-tight layer and the sealing layer, creating a pressure-leveling gap. The pressure-leveling gap and the pressure bladder are connected and both are filled with a pressure medium. The pressure-leveling gap is equipped with a medium pipe for the pressure medium to enter and exit. When the pressure inside the gas storage chamber changes, the pressure bladder is compressed or expanded under pressure, allowing the pressure medium to flow between the pressure bladder and the pressure-leveling gap.

[0008] Furthermore, the aforementioned connecting rib is provided with a through hole for the flow of pressure medium.

[0009] Furthermore, both the aforementioned sealing layer and the aforementioned airtight layer are made of flexible sealing material.

[0010] Furthermore, multiple fixing ribs are provided at intervals between the sealing layer and the concrete lining layer. One end of each fixing rib is connected to the outer wall of the sealing layer, and the other end extends into the interior of the concrete lining layer.

[0011] Furthermore, one end of the aforementioned fixing rib that extends into the aforementioned concrete lining layer is provided with a segmented structure, the segmented structure comprising a plurality of segments extending toward the periphery of the aforementioned fixing rib.

[0012] Furthermore, the aforementioned flap body includes a connector connected to the aforementioned fixing rib, and a plurality of parallel, spaced-apart extensions are connected to the outside of the connector. The extensions are located on the periphery of the aforementioned fixing rib and extend outward.

[0013] Furthermore, the aforementioned valve body has air pores.

[0014] This invention also proposes a construction method for a self-pressure-balancing underground constant-volume gas storage structure, comprising the following steps: S1: The prefabricated airtight layer and some connecting ribs form the first integral structure, while the prefabricated sealing layer, the remaining connecting ribs and fixing ribs form the second integral structure. S2: Excavation and support of gas storage chamber, consolidation grouting of surrounding rock in cavern, installation of medium pipe and gas pipe, and pre-embedding of grouting pipe for backfilling of the top arch; S3: Install the second integral structure and the inner support structure. The inner support structure is a temporary measure used to support the sealing layer. S4: Pour the concrete lining layer and perform backfill grouting for the top arch; S5: Remove the internal support structure; S6: Install the first integral structure and pressure bladder.

[0015] The beneficial effects of this invention are: By installing pressure bladders and pressure chambers inside the gas storage tank, the pressure inside and outside the airtight layer is balanced and synchronized, avoiding fatigue damage to the airtight layer under cyclic high and low pressure, which would lead to reduced sealing performance and shortened service life; the pressure gap is filled with pressure medium, which can enhance the overall sealing performance of the sealing layer.

[0016] The pressure bladder and the pressure gap are connected to form a closed cavity, which can prevent the pressure medium inside the chamber from evaporating and being carried to the turbine expander, thus avoiding adverse effects on the turbine expander, reducing the cost of dry air generation, and lowering operating costs.

[0017] A segmented fixing rib is installed on the outer side of the sealing layer. Firstly, it secures the sealing layer to the concrete lining. Secondly, it acts as an induction joint for the concrete lining, causing the concrete lining to crack along the fixing rib under internal water pressure, ensuring that cracks do not form in other areas without fixing ribs, thus preventing cracking and damage to the sealing layer. Thirdly, it guides external water to the inner surface of the segmented fixing rib, preventing the fixing rib from detaching from the concrete lining. Fourthly, it can offset some of the internal water pressure, reducing stress on the sealing layer. Attached Figure Description

[0018] Figure 1 This is a cross-sectional schematic diagram of the present invention; Figure 2 This is the present invention. Figure 1 Enlarged view of point A in the middle; Figure 3 This is the present invention. Figure 1 Enlarged view at point B in the middle; Figure 4 This is a schematic diagram of the fixed rib structure of the present invention; The markings in the diagram are as follows: 1-Gas storage chamber, 2-Pressure bladder, 3-Air-sealing layer, 4-Sealing layer, 5-Gas pipe, 6-Media pipe, 7-Connecting rib, 8-Surrounding rock layer, 9-Concrete lining layer, 10-Fixing rib, 11-Valve body, 12-Extension body, 13-Through hole, 14-Air hole, 15-Pressure gap. Detailed Implementation

[0019] The invention will be further described below with reference to the accompanying drawings.

[0020] like Figures 1-3As shown in the figure, this application proposes a self-leveling underground constant-volume gas storage structure, including a gas storage chamber 1, which is provided with a gas pipe 5 for air intake and exhaust; the inner wall of the gas storage chamber 1 is provided with a gas pipe 5 for exhaust; the exhaust pipe 5 is used to exhaust the air between each layer to the outside to ensure installation stability; the inner wall of the gas storage chamber 1 is provided with a sealing layer, a concrete lining layer 9 and a surrounding rock layer 8 from the inside to the outside; a pressure regulating component is provided in the gas storage chamber 1, which can adaptively adjust the pressure according to the real-time pressure in the gas storage chamber 1.

[0021] The aforementioned pressure regulating component includes a pressure bladder 2; the pressure bladder 2 is equipped with a one-way exhaust valve to ensure that the gas in the pressure bladder 2 is discharged into the gas storage chamber 1, ensuring that the pressure medium is free of air bubbles; the aforementioned sealing layer includes an air-tight layer 3 and a sealing layer 4 arranged sequentially from the inside to the outside, and the outer side of the aforementioned sealing layer 4 is connected to the aforementioned concrete lining layer 9; a plurality of connecting ribs 7 are provided between the aforementioned air-tight layer 3 and the aforementioned sealing layer 4, and the aforementioned connecting ribs 7 separate the aforementioned air-tight layer 3 and the aforementioned sealing layer 4 to form a flat pressure gap 15; the aforementioned flat pressure gap 15 is connected to the aforementioned pressure bladder 2 and is filled with pressure medium, and the aforementioned flat pressure gap 15 is provided with a medium pipe 6 for the pressure medium to enter and exit; when the pressure in the aforementioned gas storage chamber 1 changes, the pressure bladder 2 is compressed or expanded under the action of pressure, so that the pressure medium is pressurized and flows between the pressure bladder 2 and the flat pressure gap 15. The gas-tight layer 3 is used to seal the compressed air inside the gas storage chamber to prevent gas leakage. The sealing layer 4 seals the pressure medium inside the pressure chamber and transmits the internal pressure to the outer concrete lining layer 9 and the surrounding rock layer 8. The pressure bladder 2 is a flexible structure that is connected to the pressure gap 15 through a connecting pipe. It is in direct contact with the compressed air inside the gas storage chamber 1, converting the gas pressure into the pressure medium inside the pressure bladder 2. The sealed bladder structure prevents the pressure medium inside the chamber from evaporating and being carried to the turbine expander, thus avoiding adverse effects on the turbine expander and reducing the cost of dry air generation, thereby lowering operating costs. The concrete lining layer 9 supports the sealing layer 4, bears part of the internal and external pressure, and transmits the pressure to the surrounding rock layer 8. The pressure gap 15 is filled with a pressure medium to provide equal and uniform pressure to the gas-tight layer 3, achieving pressure balance inside and outside the gas-tight layer 3 and simultaneously preventing fatigue damage to the gas-tight layer 3 under cyclic high and low pressure, which would lead to reduced sealing performance and shortened service life. At the same time, it transmits the gas storage pressure to the concrete lining and the surrounding rock.

[0022] First, it should be stated that by installing pressure bladders and pressure chambers within the gas storage facility, the pressure inside and outside the sealed layer 3 is balanced and synchronized, preventing fatigue damage to the sealed layer 3 under cyclic high and low pressure, which would lead to reduced sealing performance and shortened service life. The pressure chamber gap 15 is filled with pressurized medium, which enhances the overall sealing performance of the sealing layer 4. The pressure bladders and pressure chamber gap 15 connect to form a closed cavity, preventing water evaporation within the chamber from being carried to the turbine expander, thus avoiding adverse effects on the turbine expander and reducing the cost of dry air generation, thereby lowering operating costs.

[0023] Specifically, the connecting rib 7 is provided with a through hole 13 for water flow to achieve hydraulic connection in the pressure chamber and avoid the problem of isolation when the pressure medium in the sealing layer 4 circulates in the pressure gap 15.

[0024] Moreover, both the sealing layer 4 and the airtight layer 3 are made of flexible sealing materials, specifically rubber or other flexible polymer materials, which have good sealing and pressure-bearing properties.

[0025] To improve the connection stability between the sealing layer 4 and the concrete lining layer 9, multiple fixing ribs 10 are provided at intervals between the sealing layer 4 and the concrete lining layer 9. One end of each fixing rib 10 is connected to the outer wall of the sealing layer 4, and the other end extends into the interior of the concrete lining layer 9. On the one hand, the sealing layer 4 is fixed to the concrete lining layer 9, and on the other hand, it serves as an induction joint for the concrete lining layer 9. Under the action of internal pressure, the concrete lining layer 9 cracks along the fixing rib 10, ensuring that no cracks are generated in other locations where fixing ribs 10 are not provided, thereby preventing the sealing layer 4 from being damaged by cracking.

[0026] like Figure 4 As shown, the end of the fixing rib 10 extending into the concrete lining layer 9 is provided with a segmented structure. The segmented structure includes multiple petals 11 extending towards the periphery of the fixing rib 10. The purpose is to guide the concrete pouring material to act on the inner surface of the segmented fixing rib 10, which can prevent the fixing rib 10 from detaching from the concrete lining. In addition, it can offset part of the pressure in the pressure medium and reduce the stress of the sealing layer 4. Moreover, in order to further improve the effect, the petal 11 includes a connector connected to the fixing rib 10. Multiple parallel and spaced extensions 12 are connected to the outside of the connector. The extensions 12 are located on the periphery of the fixing rib 10 and extend outward, increasing the segmented area.

[0027] In addition, the aforementioned petal 11 has air holes, which are used to release air during the concrete pouring process, so that the concrete around the fixing rib 10 is compacted.

[0028] This embodiment also proposes a construction method for a self-leveling underground constant-volume gas storage structure, used for constructing the aforementioned self-leveling underground constant-volume gas storage structure, including the following steps: S1: The prefabricated airtight layer 3 and part of the connecting ribs 7 form the first integral structure, and the prefabricated sealing layer 4, the remaining connecting ribs 7 and the fixing ribs 10 form the second integral structure. Specifically, in the factory, the connecting ribs 7 are fixedly installed on the outer wall of the airtight layer 3. The connecting ribs 7 are distributed at half of the outer wall of the airtight layer 3 to form the first integral structure. The other half of the connecting ribs 7 are distributed and fixed on the inner wall of the sealing layer 4. At the same time, the fixing ribs 10 are evenly arranged on the outer wall of the sealing layer 4 to form the second integral structure.

[0029] S2: Excavation and support of gas storage chamber 1, consolidation grouting of surrounding rock in the cavern, installation of medium pipe 6 and gas pipe 5, and pre-embedding of grouting pipe for backfilling the top arch; through the early cavern excavation, support and pipeline pre-embedding installation, it is ensured that subsequent construction will not be interfered with or affected, and that there is sufficient safety protection effect.

[0030] S3: Install the second integral structure and the inner support structure. The inner support structure is a temporary measure used to support the sealing layer 4. Arrange the second integral structure inside the excavated surrounding rock layer 8 and support it inside the sealing layer 4 through the inner support structure, so that a formwork structure for pouring concrete lining layer 9 is formed between the sealing layer 4 and the surrounding rock layer 8.

[0031] S4: Pour the concrete lining layer 9 and perform backfill grouting for the top arch; inject grout between the sealing layer 4 and the surrounding rock layer 8 to achieve the pouring of the concrete lining layer 9, and at the same time perform backfill grouting for the top arch to ensure the integrity and density of the overall concrete lining layer 9, and improve the support and sealing effect.

[0032] S5: Remove the internal support structure; after the concrete lining layer 9 has completely solidified, remove the internal support structure.

[0033] S6: Install the second integral structure and pressure bladder 2; install the second integral structure in the inner layer of the first integral structure, so that the connecting ribs 7 of the first integral structure and the connecting ribs 7 of the second integral structure are evenly and completely distributed in the flat pressure gap 15, and the ends of the connecting ribs 7 are stably fixed to the airtight layer 3 and the sealing layer 4 respectively.

[0034] In summary, this invention proposes a self-balancing underground constant-volume gas storage structure and construction method. By setting pressure bladders and balancing gaps 15 inside the gas storage chamber 1, the pressure inside and outside the airtight layer 3 is balanced and synchronized, avoiding fatigue damage to the airtight layer 3 under cyclic high and low pressure, which would lead to reduced sealing performance and shortened service life. The balancing gap 15 is filled with a pressurized medium, which can enhance the sealing performance of the airtight layer 3. The pressure bladder 2 is connected to the balancing gap 15 to form a closed cavity, which can prevent water in the chamber from evaporating and being carried to the turbine expander, thus avoiding adverse effects on the turbine expander and reducing the amount of dry air. The cost of gas generation is reduced, thus lowering operating costs. A segmented fixing rib 10 is installed on the outer side of the sealing layer. Firstly, it fixes the sealing layer 4 to the concrete lining layer 9. Secondly, it acts as an induction joint for the concrete lining layer 9, causing the concrete lining layer 9 to crack along the fixing rib 10 under internal water pressure, ensuring that cracks do not occur in other locations without fixing ribs 10, thereby preventing damage to the sealing layer 4 due to cracking. Thirdly, it guides external water to the inner surface of the segmented fixing rib 10, preventing the fixing rib 10 from detaching from the concrete lining layer 9. Fourthly, it can offset some of the pressure from the internal pressure medium, reducing the stress on the sealing layer 4.

Claims

1. A self-leveling underground constant-volume gas storage structure, comprising a gas storage chamber (1), characterized in that, The inner wall of the gas storage chamber (1) is provided with a sealing layer, a concrete lining layer (9) and a surrounding rock layer (8) from the inside to the outside, and the inner wall of the gas storage chamber (1) is provided with a gas pipe (5) for exhausting gas to the outside; a pressure regulating component is provided in the gas storage chamber (1), and the pressure regulating component can adaptively adjust the pressure according to the real-time pressure in the gas storage chamber (1). The pressure regulating component includes a pressure bladder (2); the sealing layer includes an air-tight layer (3) and a sealing layer (4) arranged sequentially from the inside to the outside, and the outer side of the sealing layer (4) is connected to the concrete lining layer (9); a plurality of connecting ribs (7) are provided between the air-tight layer (3) and the sealing layer (4), and the connecting ribs (7) separate the air-tight layer (3) and the sealing layer (4) into a pressure gap (15); the pressure gap (15) and the pressure bladder (2) are connected and both are filled with pressure medium, and the pressure gap (15) is provided with a medium pipe (6) for the pressure medium to enter and exit; when the pressure in the gas storage chamber (1) changes, the pressure bladder (2) is compressed or expanded under pressure, so that the pressure medium is pressurized and flows between the pressure bladder (2) and the pressure gap (15).

2. The self-leveling underground constant-volume gas storage structure according to claim 1, characterized in that, The connecting rib (7) is provided with a through hole (13) for the flow of pressure medium.

3. The self-leveling underground constant-volume gas storage structure according to claim 1, characterized in that, Both the sealing layer (4) and the airtight layer (3) are made of flexible sealing material.

4. The self-balancing underground constant-volume gas storage structure according to claim 1, characterized in that, Multiple fixing ribs (10) are provided at intervals between the sealing layer (4) and the concrete lining layer (9). One end of the fixing rib (10) is connected to the outer wall of the sealing layer (4), and the other end extends into the interior of the concrete lining layer (9).

5. The self-leveling underground constant-volume gas storage structure according to claim 4, characterized in that, The fixed rib (10) is provided with a segmented structure at one end extending into the concrete lining layer (9), the segmented structure including a plurality of petals (11) extending toward the periphery of the fixed rib (10).

6. The self-leveling underground constant-volume gas storage structure according to claim 5, characterized in that, The valve body (11) includes a connector connected to the fixing rib (10), and a plurality of parallel and spaced extensions (12) are connected to the outside of the connector. The extensions (12) are located on the periphery of the fixing rib (10) and extend outward.

7. The self-leveling underground constant-volume gas storage structure according to claim 5, characterized in that, The valve body (11) has air holes (14).

8. A construction method for a self-leveling underground constant-volume gas storage structure, used for constructing the self-leveling underground constant-volume gas storage structure according to any one of claims 4-7, characterized in that, Includes the following steps: S1: The prefabricated airtight layer (3) and part of the connecting ribs (7) form the first integral structure, and the prefabricated sealing layer (4), the remaining connecting ribs (7) and the fixing ribs (10) form the second integral structure; S2: Excavation and support of gas storage chamber (1), consolidation grouting of surrounding rock of the cavern, installation of medium pipe (6) and gas pipe (5), and pre-embedding of top arch backfill grouting pipe; S3: Install the second integral structure and the inner support structure. The inner support structure is a temporary measure used to support the sealing layer (4). S4: Pour concrete lining layer (9) and perform backfill grouting for the top arch; S5: Remove the internal support structure; S6: Install the first integral structure and pressure bladder (2).

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