Symmetrically-arranged compressed air energy storage reservoir plug structure

Abstract

The invention relates to the technical field of compressed air energy storage and underground engineering construction, and particularly discloses a symmetrically-arranged compressed air energy storage reservoir plug structure which comprises a connecting structure, and a maintenance channel is arranged in the connecting structure; a first plug and a second plug are arranged at the two ends of the connecting structure respectively, and the first plug and the second plug are symmetrically arranged; sealing doors are arranged at the ends of the first plug and the second plug, the sealing doors are arranged at the two ends of the overhaul channel, and the overhaul channel and the energy storage warehouse are sealed through the sealing doors; the first plug and the second plug are each provided with an air injection channel and an air exhaust channel. According to the symmetrically-arranged plug structure of the compressed air energy storage warehouse, the plug adopts the wedge-shaped design that the thick end faces the interior of the energy storage warehouse so as to optimize stress distribution, and the overhaul channel is of a variable cross-section structure so that the sealing efficiency can be improved; stress balance is realized through bidirectional symmetrical layout, the structural size is reduced, the sealing performance is excellent, and the maintenance is convenient, so that the safety and the operation efficiency of the compressed air energy storage system are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of compressed air energy storage and its underground engineering construction, and particularly relates to a plug structure for a compressed air energy storage reservoir with a symmetrical arrangement. Background Art

[0002] Compressed Air Energy Storage (CAES for short) is an important physical energy storage method, which has the advantages of large energy storage capacity, long operation life, environmental friendliness, low operation cost, etc. Especially in an advanced adiabatic system (AA-CAES), the system efficiency and environmental performance are significantly improved.

[0003] Underground compressed air energy storage technology usually uses abandoned mines, rock caves, salt caverns, etc. to construct a compressed air energy storage reservoir, and realizes the closure and airtight sealing of the cave entrance through a plug structure. The existing plug structures mainly adopt single-end rigid plugs or multi-stage sealing structures, but there are the following problems: 1. Large structural volume: Traditional plugs are mostly integral concrete structures, with a long construction period, large material consumption, and large disturbance to the surrounding rock. 2. Uneven stress: Single-end compression is prone to cause stress concentration, and shear cracks or slip failures are likely to occur at the contact interface between the plug and the surrounding rock, resulting in air leakage at the plug position.

[0004] Therefore, there is an urgent need to provide a plug structure with more reasonable structural stress, more compact volume, convenient construction and operation and maintenance, and high airtightness at the same time to meet the actual engineering needs of the underground CAES system. Summary of the Invention

[0005] The purpose of the present invention is to provide a plug structure for a compressed air energy storage reservoir with a symmetrical arrangement to solve the problems existing in the above-mentioned prior art.

[0006] To achieve the above purpose, the present invention provides a plug structure for a compressed air energy storage reservoir with a symmetrical arrangement, including a connection structure, and a maintenance passage is arranged inside the connection structure; a first plug and a second plug are respectively arranged at both ends of the connection structure, the first plug and the second plug are symmetrically arranged, sealing doors are arranged at the ends of the first plug and the second plug, the sealing doors are arranged at both ends of the maintenance passage, and the maintenance passage is sealed with the energy storage reservoir through the sealing doors; injection channels and exhaust channels are arranged on both the first plug and the second plug.

[0007] Preferably, the first plug and the second plug are symmetrically arranged at both ends of the connection structure, both the first plug and the second plug adopt a wedge-shaped structure, and the thick end of the wedge-shaped structure faces the inside of the energy storage reservoir.

[0008] Preferably, the maintenance passage is a variable cross-section structure, and the width of the maintenance passage is the narrowest at the end close to the sealing door.

[0009] Preferably, a maintenance opening is provided on the connection structure, and the maintenance passage communicates with a traffic passage for personnel and equipment to enter and exit through the maintenance opening. The width of the traffic passage is 2.5 m to 5 m, and the height is 3 m to 5 m.

[0010] Preferably, an inner sealing ring and an outer sealing ring are provided on the sealing door, and a pressing device is provided on the outer sealing ring. The pressing device is used to tightly fit the outer sealing ring with the surface of the first plug or the second plug after the sealing door is closed.

[0011] Preferably, both the first plug and the second plug are of concrete structure, and the strength grade of the concrete used in the concrete structure is not lower than C40.

[0012] Preferably, one-way valves for controlling the gas flow direction are provided in both the gas injection channel and the exhaust channel.

[0013] Preferably, the operation method of the plug structure of the symmetrically arranged compressed air energy storage reservoir includes the following steps:

[0014] Step 1, perform maintenance inspection on the first plug and the second plug to confirm that the plug structure meets the safety use requirements;

[0015] Step 2, simultaneously inject compressed air into the energy storage reservoir through the gas injection channels on the first plug and the second plug to achieve symmetric preloading;

[0016] Step 3, complete the storage of the compressed air energy in the energy storage reservoir;

[0017] Step 4, release the compressed air in the energy storage reservoir through the exhaust channels on the first plug and the second plug, and use the compressed air to drive a generator set to generate electricity.

[0018] Preferably, the difference in the flow rate of the compressed air injected into the energy storage reservoir and released for power generation from the first plug and the second plug is not greater than 10%.

[0019] Preferably, in step 1, the maintenance inspection of the first plug and the second plug includes detecting the sealing rings on the sealing door and inspecting and cleaning the maintenance passage.

[0020] Compared with the prior art, the present invention has the following advantages and technical effects:

[0021] The plug structure of the symmetrically arranged compressed air energy storage chamber provided by the present invention optimizes the stress distribution through the double-plug symmetric wedge design, achieving force balance, volume miniaturization, enhanced anti-slip and airtightness, and improving the sealing efficiency with a variable cross-section channel; enhancing the overall safety and operating efficiency of the underground CAES system.

[0022] Adopting a symmetric layout enables the plugs to be evenly stressed, reducing the concentration of force on a single end and lowering the peak value of local stress; and due to the symmetric layout sharing the pressure, the volume of a single plug can be reduced by more than 30%, saving material and manufacturing costs; the connection structure and the two plugs form an overall framework, improving the structural stiffness and eliminating the hidden danger of shear slip failure; corresponding concrete strength grades (C40 - C50) can be selected according to different surrounding rock categories (grade II - grade V). BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0024] Figure 1 It is the front view of the plug structure of the symmetrically arranged compressed air energy storage chamber of the present invention;

[0025] Figure 2 It is the top view of the plug structure of the symmetrically arranged compressed air energy storage chamber of the present invention;

[0026] Figure 3 It is a schematic diagram of the application of the present invention in an annular compressed air energy storage chamber in Embodiment 1;

[0027] Figure 4 It is a schematic diagram of the application of the present invention in a double-port symmetric linear compressed air energy storage chamber in Embodiment 2;

[0028] In the figure: 1. First plug; 2. Second plug; 3. Connection structure; 4. Maintenance passage; 5. Maintenance opening; 6. Sealing door; 7. Gas injection channel; 8. Exhaust channel; 9. Traffic channel. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention. The following will describe the present invention in detail with reference to the drawings and in combination with the embodiments.

[0030] Such as Figures 1 to 2As shown in the figure, the present invention provides a plug structure for a compressed air energy storage reservoir with a symmetrical layout, including a connection structure 3, and a maintenance passage 4 is arranged inside the connection structure 3; a first plug 1 and a second plug 2 are respectively arranged at both ends of the connection structure 3, the first plug 1 and the second plug 2 are symmetrically arranged, and sealing doors 6 are arranged at the ends of the first plug 1 and the second plug 2. The sealing doors 6 are arranged at both ends of the maintenance passage 4, and the maintenance passage 4 is sealed with the energy storage reservoir through the sealing doors 6; injection channels 7 and exhaust channels 8 are arranged on both the first plug 1 and the second plug 2.

[0031] The first plug 1 and the second plug 2 are respectively arranged at the two reservoir openings of a compressed air energy storage reservoir with a double-port symmetrical or annular structure. The first plug 1 and the second plug 2 are symmetrically arranged along the axis of the compressed air energy storage reservoir. The connection structure 3 is arranged between the first plug 1 and the second plug 2. The connection structure 3 is a reinforced concrete structure. The first plug 1 and the second plug 2 form a through connection channel through the connection structure 3, which is used to integrally connect the two plugs structurally and enhance the overall stiffness; the maintenance passage 4 is arranged inside the connection structure 3, and the maintenance passage 4 is used to provide a passage space for maintenance personnel to pass through; the opening direction of the sealing door 6 faces the inside of the compressed air energy storage reservoir; both the injection channel 7 and the exhaust channel 8 are arranged in the upper region of the internal structure of the first plug 1 and the second plug 2. The injection channel 7 and the exhaust channel 8 are arranged in the concrete plug through a nested lining structure. The channel wall is coated with a pressure-resistant steel pipe or a composite material pipe, and is closely matched with the internal structure of the plug through a sealing water stop ring. The injection channel 7 is used to inject high-pressure air into the compressed air energy storage reservoir, and the exhaust channel 8 is used to export the compressed air in the compressed air energy storage reservoir to the generator set during the air release power generation stage.

[0032] The plug structure for a compressed air energy storage reservoir provided by the present invention realizes force balance, volume miniaturization and airtight closure through a two-way symmetrical layout, improving the overall safety and operation efficiency of the underground CAES system.

[0033] In a further optimized solution, the first plug 1 and the second plug 2 are symmetrically arranged at both ends of the connection structure 3. Both the first plug 1 and the second plug 2 adopt a wedge-shaped structure, and the thick end of the wedge-shaped structure faces the inside of the energy storage reservoir.

[0034] The internal structure is reinforced with steel bars and cast in place with high-strength concrete. The wedge geometry helps the pressure-bearing surface to stably fit the surrounding rock, reducing the risk of axial slip.

[0035] In a further optimized solution, the maintenance passage 4 is a variable cross-section structure, and the width of the maintenance passage 4 is the narrowest at the end close to the sealing door 6.

[0036] The maintenance passage 4 gradually narrows near the wedge-shaped plug, which is used to improve the structural compactness and enhance the sealing efficiency.

[0037] For a further optimized solution, a maintenance opening 5 is provided on the connection structure 3, and the maintenance passage 4 is connected through the maintenance opening 5 to a traffic passage 9 for personnel and equipment to enter and exit. The width of the traffic passage 9 is 2.5 to 5 meters, and the height is 3 to 5 meters.

[0038] For a further optimized solution, an inner sealing ring and an outer sealing ring are provided on the sealing door 6, and a pressing device is provided on the outer sealing ring. The pressing device is used to closely fit the outer sealing ring with the surface of the first plug 1 or the second plug 2 after the sealing door 6 is closed.

[0039] For a further optimized solution, both the first plug 1 and the second plug 2 are of concrete structure, and the strength grade of the concrete used in the concrete structure is not lower than C40.

[0040] For a further optimized solution, one-way valves for controlling the gas flow direction are provided in both the gas injection channel 7 and the exhaust channel 8.

[0041] For a further optimized solution, an operation method for the plug structures of symmetrically arranged compressed air energy storage reservoirs includes the following steps:

[0042] Step 1: Inspect and test the first plug 1 and the second plug 2 to confirm that the plug structure meets the requirements for safe use;

[0043] After the plug construction is completed, perform airtightness detection and structural integrity testing, including methods such as using the positive pressure gas injection method to test the leakage rate and the thermal imaging method to monitor the uniformity of the temperature field;

[0044] Step 2: Before the first operation, inject compressed air into the energy storage reservoir synchronously through the gas injection channels 7 on the first plug 1 and the second plug 2 to achieve symmetric preloading;

[0045] Step 3: During the gas storage operation stage, ensure the balance of the flow rate and pressure of the two gas injection channels 7 to improve the system stability until the storage of the compressed air energy in the energy storage reservoir is completed;

[0046] Step 4: During the power generation stage, simultaneously open the exhaust channels 8, release the compressed air in the energy storage reservoir through the exhaust channels 8 on the first plug 1 and the second plug 2, and use the compressed air to drive the generator set for power generation. When releasing the compressed air in the energy storage reservoir, ensure the symmetry of the air flow rate to avoid stress imbalance caused by unilateral air release.

[0047] For a further optimized solution, the difference in the flow rate of the compressed air injected into the energy storage reservoir and released for power generation from the first plug 1 and the second plug 2 is not greater than 10%.

[0048] For a further optimized solution, in Step 1, the inspection and testing of the first plug 1 and the second plug 2 include the inspection of the sealing rings on the sealing door 6 and the inspection and cleaning of the maintenance passage 4.

[0049] Embodiment 1

[0050] The symmetric plug structure of the compressed air energy storage reservoir provided by the present invention is applied to the symmetric plug structure of the annular compressed air energy storage reservoir.

[0051] As Figure 3 shown, the annular compressed air energy storage reservoir is composed of a closed annular tunnel. The cross-section of the tunnel is circular, the surrounding rock grade is Class IV, and the average buried depth is about 300 meters.

[0052] In this embodiment, a first plug 1 and a second plug 2 are respectively arranged at both ends of the annular compressed air energy storage reservoir. The first plug 1 and the second plug 2 are symmetrically arranged along the loop of the compressed air energy storage reservoir. The two plugs are connected by a connecting structure 3 made of reinforced concrete, and the whole is arranged in a closed ring strip shape to form a closed gas storage system.

[0053] Both the first plug 1 and the second plug 2 are wedge-shaped structures. Inside each plug, there is a criss-cross HRB400 grade steel bar skeleton, and it is cast and formed with C40 high-strength concrete. The axial length of a single plug is 6.0 meters.

[0054] An inspection hole 5 is arranged at the center of the traffic channel 9 of the connecting structure 3. The size of the inspection hole 5 is 3600 mm in width and 4000 mm in height, which is convenient for daily inspection and maintenance. A sealing door 6 is arranged at the hole of the inspection channel 4. The door is made of Q345 material. The sealing ring on the sealing door 6 is a double-layer composite rubber ring, which can withstand a maximum working pressure of 15 MPa. The opening direction of the sealing door 6 points to the side of the compressed air energy storage reservoir, and it is connected with the door frame by a replaceable hinge.

[0055] The gas injection channel 7 and the gas exhaust channel 8 are arranged in the connecting structure 3 through a nested lining structure.

[0056] After the installation of this structure, through double-end gas injection and pressure equalization operations, the overall force balance of the annular structure of the compressed air energy storage reservoir can be effectively maintained. The airtight performance is verified by preliminary tests, and the leakage rate is 0.

[0057] Embodiment 2

[0058] The symmetric plug structure of the compressed air energy storage reservoir provided by the present invention is applied to the double-port symmetric linear compressed air energy storage reservoir, which is constructed by using abandoned mine roadways.

[0059] As Figure 4 shown, the compressed air energy storage reservoir is a linear and symmetrically distributed tunnel-type compressed air energy storage reservoir. The total length of the compressed air energy storage reservoir is about 1600 meters, 800 meters on one side, and the inner diameter is 6 meters. The connection part of the compressed air energy storage reservoir is connected to the traffic service tunnel, and the middle part is the main gas storage section. The surrounding rock is Class II surrounding rock, a limestone formation with high strength, and full-section support and strengthened lining are required.

[0060] A first plug 1 and a second plug 2 are placed at either end of the compressed gas energy storage reservoir. Both are symmetrically positioned, facing the mine entrances and exits. A variable-section inspection passage 4 is located within the plug structure, measuring 2800 mm at its widest point and 1500 mm at its narrowest point, with a uniform height of 2800 mm.

[0061] A traffic channel 9 is set in the middle of the two plugs, with a cross-section of 3500 mm wide and 4800 mm high, for transporting and repairing equipment. A maintenance opening 5 is set at the intersection of traffic channel 9 and maintenance channel 4. The maintenance opening 5 is 2600 mm wide and 3600 mm high.

[0062] The sealing door 6 adopts a commercially available double-limit high-pressure cabin door structure and is equipped with a pressure-sensing locking device. It automatically locks when the internal air pressure is higher than 0.2 MPa to prevent backflow or gas leakage in the event of an accident.

[0063] The gas injection channel 7 and the exhaust channel 8 are respectively embedded in high-strength steel pipes with an inner diameter of DN250. The gas injection port and the exhaust port are located at the upper 3 / 4 height position, and both are connected to the remote gas distribution center through connecting flanges.

[0064] During operation, this plugging structure features simultaneous air injection and deflation at both ends, along with a flow balance control system to ensure a pressure differential of no more than ±0.1 MPa, ensuring stable and reliable operation. Demonstration has shown that this structure can withstand a maximum operating pressure exceeding 12 MPa, and exhibits excellent sealing and repeatability.

[0065] The above are only preferred specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or replacements that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A plug structure for a compressed air energy storage reservoir with a symmetrical arrangement, characterized in that It includes a connection structure (3) with a maintenance passage (4) provided therein; at both ends of the connection structure (3), a first plug (1) and a second plug (2) are respectively provided. The first plug (1) and the second plug (2) are symmetrically arranged. At the ends of the first plug (1) and the second plug (2), sealing doors (6) are provided. The sealing doors (6) are arranged at both ends of the maintenance passage (4). The maintenance passage (4) is sealed with the energy storage reservoir through the sealing doors (6); injection channels (7) and exhaust channels (8) are provided on both the first plug (1) and the second plug (2).

2. The plug structure of the compressed air energy storage reservoir with symmetric arrangement according to claim 1, characterized in that, The first plug (1) and the second plug (2) are symmetrically arranged at both ends of the connection structure (3). Both the first plug (1) and the second plug (2) adopt a wedge-shaped structure, and the thick end of the wedge-shaped structure faces the inside of the energy storage reservoir.

3. The plug structure of the compressed air energy storage reservoir with symmetric arrangement according to claim 1, characterized in that, The maintenance passage (4) is a variable cross-section structure, and the width of the end of the maintenance passage (4) close to the sealing door (6) is the narrowest.

4. The plug structure of the compressed air energy storage reservoir with symmetric arrangement according to claim 1, characterized in that, An inspection opening (5) is provided on the connection structure (3). The maintenance passage (4) is connected to a traffic passage (9) for personnel and equipment to enter and exit through the inspection opening (5). The width of the traffic passage (9) is 2.5 meters to 5 meters, and the height is 3 meters to 5 meters.

5. The plug structure of the compressed air energy storage reservoir with symmetric arrangement according to claim 1, characterized in that, Inner sealing rings and outer sealing rings are provided on the sealing door (6). A pressing device is provided on the outer sealing ring. The pressing device is used to closely fit the outer sealing ring with the surface of the first plug (1) or the second plug (2) after the sealing door (6) is closed.

6. The plug structure of the compressed air energy storage reservoir with symmetric arrangement according to claim 1, characterized in that Both the first plug (1) and the second plug (2) are of concrete structure, and the strength grade of the concrete used in the concrete structure is not lower than C40.

7. The plug structure of the compressed air energy storage reservoir with symmetric arrangement according to claim 1, characterized in that, Check valves for controlling the gas flow direction are provided in both the injection channel (7) and the exhaust channel (8).

8. The plug structure of the symmetrically arranged compressed air energy storage reservoir according to any one of claims 1-7, characterized in that, The operation method of the symmetrically arranged plug structure of the compressed air energy storage reservoir includes the following steps: Step 1: Inspect and detect the first plug (1) and the second plug (2) to confirm that the plug structure meets the safety use requirements; Step 2: Synchronously inject compressed air into the energy storage reservoir through the injection channels (7) on the first plug (1) and the second plug (2) to achieve symmetric preloading; Step 3: Complete the storage of the compressed air energy in the energy storage reservoir; Step 4: Release the compressed air in the energy storage reservoir through the exhaust channels (8) on the first plug (1) and the second plug (2), and use the compressed air to drive the generator set for power generation.

9. The plug structure of the compressed air energy storage reservoir with symmetric arrangement according to claim 8, characterized in that, The difference in the flow rate of the compressed air injected into the energy storage reservoir and released for power generation from the first plug (1) and the second plug (2) is not greater than 10%.

10. The plug structure of the compressed air energy storage reservoir with symmetric arrangement according to claim 8, characterized in that, In step 1, the inspection and detection of the first plug (1) and the second plug (2) include detecting the sealing rings on the sealing door (6) and inspecting and cleaning the maintenance passage (4).

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