A symmetrically arranged plug structure for compressed air energy storage

Abstract

The present invention relates to the technical field of compressed air energy storage and its underground engineering construction, and specifically discloses a symmetrically arranged compressed air energy storage reservoir plug structure, including a connecting structure, in which an inspection channel is provided; a first plug and a second plug are respectively provided at both ends of the connecting structure, and the first plug and the second plug are symmetrically arranged; sealing doors are provided at the ends of the first plug and the second plug, and the sealing doors are provided at both ends of the inspection channel, and the inspection channel and the energy storage reservoir are sealed by the sealing doors; an injection channel and an exhaust channel are provided on the first plug and the second plug. The symmetrically arranged compressed air energy storage reservoir plug structure provided by the present invention adopts a wedge-shaped design with the thick end facing the interior of the energy storage reservoir to optimize the force distribution, and the inspection channel is a variable cross-section structure to improve the sealing efficiency; the bidirectional symmetrical layout is used to achieve force balance, reduced structural volume, superior sealing performance and convenient maintenance, thereby improving the safety and operation efficiency of the compressed air energy storage system.

Description

Technical Field

[0001] The present invention relates to the technical field of compressed air energy storage and underground engineering construction thereof, and in particular to a symmetrically arranged plug structure for a compressed air energy storage reservoir. Background Art

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

[0003] Underground compressed gas energy storage technology typically utilizes abandoned mines, caverns, and salt caverns to construct compressed gas energy storage reservoirs, with the cavern entrance sealed and airtightly sealed using a plug structure. Existing plug structures primarily utilize single-end rigid plugs or multi-stage sealing structures, but these have the following problems: 1. Large structural volume: Traditional plugs are mostly monolithic concrete structures, which have long construction cycles, high material consumption, and significant disturbance to the surrounding rock. 2. Uneven force: Single-end pressure can easily lead to stress concentration, and shear cracks or slippage damage can easily occur at the interface between the plug and the surrounding rock, resulting in air leakage at the plug location.

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

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

[0006] To achieve the above-mentioned objectives, the present invention provides a symmetrically arranged compressed air energy storage reservoir plug structure, including a connecting structure, in which an inspection channel is provided; a first plug and a second plug are respectively provided at both ends of the connecting structure, and the first plug and the second plug are symmetrically arranged, and the ends of the first plug and the second plug are both provided with sealing doors, which are arranged at both ends of the inspection channel, and the inspection channel and the energy storage reservoir are sealed by the sealing doors; the first plug and the second plug are both provided with an injection channel and an exhaust channel.

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

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

[0009] Preferably, an inspection hole is provided on the connecting structure, and the inspection passage is connected to a traffic passage for personnel and equipment to enter and exit through the inspection hole. The width of the traffic passage is 2.5 meters to 5 meters, and the height is 3 meters to 5 meters.

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

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

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

[0013] Preferably, the operating method of the symmetrically arranged compressed air energy storage plug structure comprises the following steps:

[0014] Step 1: inspect and test the first plug and the second plug to confirm that the plug structure meets the safety requirements;

[0015] Step 2: Synchronously injecting compressed air into the energy storage reservoir through the air injection channels on the first plug and the second plug to achieve symmetrical preloading;

[0016] Step 3: Complete the storage of compressed air energy in the energy storage tank;

[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 the generator set to generate electricity.

[0018] Preferably, the difference in flow rate of compressed air injected into the energy storage reservoir and discharged for power generation from the first plug and the second plug is no more than 10%.

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

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

[0021] The symmetrically arranged compressed air energy storage reservoir plug structure provided by the present invention optimizes stress distribution through the symmetrical wedge-shaped design of the double plugs, achieves force balance, miniaturization, enhanced anti-slip and airtight closure, and the variable cross-section channel improves sealing efficiency, thereby improving the overall safety and operating efficiency of the underground CAES system.

[0022] The symmetrical layout makes the pressure on the plug balanced, reduces the force concentration on one end, and reduces the local stress peak. And because the symmetrical layout shares the pressure, the volume of a single plug can be reduced by more than 30%, saving material and manufacturing costs. The connecting structure and the two plugs form an overall frame, which improves the structural rigidity and eliminates the hidden danger of shear slip damage. The corresponding concrete strength grade (C40~C50) can be selected for different surrounding rock categories (Grade II~Grade V). BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

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

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

[0026] Figure 3 Schematic diagram of the present invention applied to an annular compressed air energy storage reservoir in Example 1;

[0027] Figure 4 This is a schematic diagram of the present invention applied to a double-port symmetrical linear compressed gas energy storage reservoir in Example 2;

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

[0029] It should be noted that, unless there is a conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other. The embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present invention. The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0030] like Figures 1 to 2As shown, the present invention provides a symmetrically arranged compressed air energy storage reservoir plug structure, including a connecting structure 3, in which an inspection channel 4 is provided; a first plug 1 and a second plug 2 are respectively provided at both ends of the connecting structure 3, and the first plug 1 and the second plug 2 are symmetrically arranged, and sealing doors 6 are provided at the ends of the first plug 1 and the second plug 2, which are arranged at both ends of the inspection channel 4, and the inspection channel 4 and the energy storage reservoir are sealed by the sealing doors 6; an injection channel 7 and an exhaust channel 8 are provided on 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 ports of the 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 connecting structure 3 is arranged between the first plug 1 and the second plug 2. The connecting structure 3 is a reinforced concrete structure. The first plug 1 and the second plug 2 form a through connecting channel through the connecting structure 3, which is used to connect the two plugs as a whole in the structure and enhance the overall rigidity; the maintenance channel 4 is arranged inside the connecting structure 3, and the maintenance channel 4 is used to provide maintenance personnel with a passage. Passage space; the opening direction of the sealed door 6 is toward the inside of the compressed air energy storage reservoir; the air injection channel 7 and the exhaust channel 8 are both arranged in the upper area of ​​the internal structure of the first plug 1 and the second plug 2, and the air injection channel 7 and the exhaust channel 8 are arranged in the concrete plug through a nested lining structure. The channel wall is covered with a pressure-resistant steel pipe or a composite material pipe, and is tightly matched with the internal structure of the plug through a sealing water stop ring. The air 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 discharge the compressed air in the compressed air energy storage reservoir to the generator set during the deflation power generation stage.

[0032] The symmetrically arranged compressed air energy storage reservoir plug structure provided by the present invention achieves force balance, miniaturization and airtight sealing through a bidirectional symmetrical layout, thereby improving the overall safety and operating efficiency of the underground CAES system.

[0033] According to a further optimized solution, the first plug 1 and the second plug 2 are symmetrically arranged at both ends of the connecting structure 3. The first plug 1 and the second plug 2 both adopt a wedge-shaped structure, and the thick end of the wedge-shaped structure faces the interior of the energy storage tank.

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

[0035] According to a further optimization scheme, the inspection channel 4 has a variable cross-section structure, and the width of the inspection channel 4 is narrowest at one end close to the sealing door 6 .

[0036] The inspection channel 4 gradually narrows near the wedge-shaped plug to improve the compactness of the structure and enhance the sealing efficiency.

[0037] To further optimize the solution, an inspection hole 5 is opened on the connecting structure 3, and the inspection channel 4 is connected to a traffic channel 9 for personnel and equipment to enter and exit through the inspection hole 5. The width of the traffic channel 9 is 2.5 meters to 5 meters, and the height is 3 meters to 5 meters.

[0038] According to a further optimization scheme, an inner sealing ring and an outer sealing ring are provided on the sealing door 6, and a clamping device is provided on the outer sealing ring, which is used to tightly fit the outer sealing ring to the surface of the first plug 1 or the second plug 2 after the sealing door 6 is closed.

[0039] According to a further optimization scheme, both the first plug 1 and the second plug 2 are concrete structures, and the strength grade of the concrete used in the concrete structure is not lower than C40.

[0040] As a further optimization solution, both the gas injection channel 7 and the gas exhaust channel 8 are provided with a one-way valve for controlling the direction of gas flow.

[0041] Further optimizing the scheme, the operation method of the symmetrically arranged compressed gas energy storage plug structure 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 safety requirements;

[0043] After the plugging construction is completed, air tightness testing and structural integrity testing are carried out, including the use of positive pressure gas injection method to test the leakage rate and thermal imaging method to monitor the uniformity of the temperature field;

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

[0045] Step 3: Gas storage operation phase, ensuring the flow and pressure balance of the two gas injection channels 7, improving system stability, until the storage of compressed air energy in the energy storage reservoir is completed;

[0046] Step 4: During the power generation phase, the exhaust channel 8 is opened simultaneously to release the compressed air in the energy storage reservoir through the exhaust channel 8 on the first plug 1 and the second plug 2. The compressed air is used to drive the generator set to generate electricity. When releasing the compressed air in the energy storage reservoir, ensure that the air flow is symmetrical to avoid stress imbalance caused by unilateral degassing.

[0047] According to a further optimization scheme, the difference between the flow rates of the compressed air injected into the energy storage reservoir and the compressed air discharged for power generation from the first plug 1 and the second plug 2 is no more than 10%.

[0048] According to a further optimized solution, the inspection and testing of the first plug 1 and the second plug 2 in step 1 includes inspecting the sealing ring on the sealing door 6 and inspecting and cleaning the inspection channel 4 .

[0049] Example 1

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

[0051] like Figure 3 As shown, the annular compressed air energy storage reservoir consists of a closed annular tunnel with a circular cross-section, a surrounding rock grade of Class IV, and an average burial depth of about 300 meters.

[0052] In this embodiment, a first plug 1 and a second plug 2 are respectively provided at the interfaces 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 ring line of the compressed air energy storage reservoir. The two plugs are connected by a connecting structure 3 made of reinforced concrete. The whole is arranged in a closed ring belt shape, forming a closed gas storage system.

[0053] The first plug 1 and the second plug 2 are both wedge-shaped structures. Each plug is provided with a crisscross HRB400 grade steel bar skeleton inside and is cast with C40 high-strength concrete. The axial length of a single plug is 6.0 meters.

[0054] An inspection opening 5, measuring 3600 mm wide and 4000 mm high, is located at the center of the traffic passage 9 connecting the structure 3, facilitating routine inspection and maintenance. The opening of the inspection passage 4 is equipped with a sealed door 6, made of Q345 material. The sealing ring on this door is a double-layer composite rubber ring capable of withstanding a maximum operating pressure of 15 MPa. The door opens toward the compressed air energy storage reservoir and is connected to the door frame with a replaceable hinge.

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

[0056] After the structure is installed, double-end gas injection and pressure equalization operations can effectively maintain the overall force balance of the annular structure of the compressed gas energy storage reservoir. The airtight performance has been verified by preliminary tests and the leakage rate is 0.

[0057] Example 2

[0058] The symmetrically arranged compressed air energy storage reservoir plug structure provided by the present invention is applied to a double-port symmetrical linear compressed air energy storage reservoir, which is constructed using abandoned mine tunnels.

[0059] like Figure 4 As shown, the compressed gas energy storage reservoir is a straight, symmetrically distributed tunnel-type compressed gas energy storage reservoir with a total length of approximately 1,600 meters, 800 meters on each side, and an inner diameter of 6 meters. The compressed gas energy storage reservoir entrance connects to the traffic service tunnel, with the central section serving as the main gas storage section. The surrounding rock is Class II, a high-strength limestone stratum, requiring full-section support and reinforced lining.

[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. An operating method for a symmetrically arranged compressed air energy storage plug structure, characterized in that: A symmetrically arranged compressed air energy storage reservoir plug structure comprises a connecting structure (3), wherein an inspection channel (4) is provided in the connecting structure (3); a first plug (1) and a second plug (2) are respectively provided at both ends of the connecting structure (3), wherein the first plug (1) and the second plug (2) are symmetrically arranged at both ends of the connecting structure (3), wherein the first plug (1) and the second plug (2) both adopt a wedge-shaped structure, and the thick end of the wedge-shaped structure faces the interior of the energy storage reservoir; a sealing door (6) is provided at the end of each of the first plug (1) and the second plug (2), wherein the sealing door (6) is provided at both ends of the inspection channel (4), and the inspection channel (4) and the energy storage reservoir are sealed by the sealing door (6); an air injection channel (7) and an exhaust channel (8) are both provided on each of the first plug (1) and the second plug (2); The operational approach includes the following steps: Step 1: inspect and test the first plug (1) and the second plug (2) to confirm that the plug structure meets the safety requirements; Step 2: Synchronously injecting compressed air into the energy storage reservoir through the air injection channels (7) on the first plug (1) and the second plug (2) to achieve symmetrical preloading; Step 3: Complete the storage of compressed air energy in the energy storage tank; Step 4: releasing the compressed air in the energy storage reservoir through the exhaust passage (8) on the first plug (1) and the second plug (2), and using the compressed air to drive the generator set to generate electricity; The difference between the flow rates of the compressed air injected into the energy storage reservoir and the compressed air discharged for power generation from the first plug (1) and the second plug (2) is no more than 10%.

2. The method for operating the symmetrically arranged compressed gas energy storage plug structure according to claim 1 is characterized in that: The inspection channel (4) has a variable cross-section structure, and the width of the inspection channel (4) is narrowest at one end close to the sealing door (6).

3. The method for operating the symmetrically arranged compressed air energy storage plug structure according to claim 1 is characterized in that: The connecting structure (3) is provided with an inspection hole (5), and the inspection passage (4) is connected to a traffic passage (9) for personnel and equipment to enter and exit through the inspection hole (5). The traffic passage (9) has a width of 2.5 meters to 5 meters and a height of 3 meters to 5 meters.

4. The method for operating the symmetrically arranged compressed gas energy storage plug structure according to claim 1 is characterized in that: The sealing door (6) is provided with an inner sealing ring and an outer sealing ring, and the outer sealing ring is provided with a pressing device, and the pressing device is used to tightly fit the outer sealing ring to the surface of the first plug (1) or the second plug (2) after the sealing door (6) is closed.

5. The method for operating the symmetrically arranged compressed air energy storage plug structure according to claim 1 is characterized in that: The first plug (1) and the second plug (2) are both concrete structures, and the strength grade of the concrete used in the concrete structures is not less than C40.

6. The method for operating the symmetrically arranged compressed air energy storage plug structure according to claim 1, characterized in that: The gas injection channel (7) and the gas exhaust channel (8) are both provided with a one-way valve for controlling the direction of gas flow.

7. The method for operating the symmetrically arranged compressed gas energy storage plug structure according to claim 1, characterized in that: In step 1, the inspection and testing of the first plug (1) and the second plug (2) includes inspecting the sealing ring on the sealing door (6) and inspecting and cleaning the inspection channel (4).

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