Salt cavern gravity compressed air energy storage system and method thereof

Abstract

The invention discloses a salt cavern gravity compressed air energy storage system which comprises a salt cavern, a vertical shaft is vertically formed in the top of the salt cavern and communicated to the ground surface, a sealing film is arranged on the side wall of an inner cavity of the salt cavern and divides the salt cavern into a water storage cavity and an air storage cavity, and the bottom of the air storage cavity is connected with one end of an air pipe. A piston is arranged in the vertical shaft, a gravity block is arranged at the top of the piston, a water pipe communicated with the water storage cavity is arranged at the bottom of the water storage pool, and a water conservancy generator set is arranged on the water pipe. Liquid gravity is matched with salt cavern gas storage, liquid can be matched with the irregular shape of a salt cavern, construction is reduced, energy density is increased, construction difficulty can be reduced through ground surface construction, the problem that a traditional compressed air energy storage system is large in investment cost is solved, and meanwhile the problem that salt cavern resources are reused is solved.

Description

Technical Field

[0001] The invention relates to a salt cavern gravity compressed air energy storage system and a method thereof, belonging to the technical field of gravity compressed air energy storage. Background Art

[0002] Compressed air energy storage uses air as an energy carrier. Large-scale compressed air energy storage uses excess electricity to compress air and store it in a gas storage structure. When needed, the compressed air is mixed with natural gas, burned and expanded to drive the gas turbine to generate electricity. Its advantage is that it has a peak-shaving function and is suitable for large-scale wind farms, because the mechanical work generated by wind energy can directly drive the compressor to rotate, reducing the intermediate conversion into electricity, thereby improving efficiency. In the prior art, the construction and investment costs of traditional compressed air energy storage systems are relatively high. The construction of compressed air energy storage systems based on salt caverns can utilize waste resources, but the irregular shape of salt caverns makes construction difficult. Therefore, we propose a salt cavern gravity compressed air energy storage system and method to solve the above problems. Summary of the invention

[0003] The purpose of the present invention is to provide a salt cavern gravity compressed air energy storage system, and also to provide a salt cavern gravity compressed air energy storage system and a method thereof. The present invention utilizes liquid gravity in conjunction with salt cavern gas storage. The liquid can adapt to the irregular shape of the salt cavern, reduce construction, and increase energy density, thereby solving the problem of high investment cost of traditional compressed air energy storage systems and solving the problem of reusing salt cavern resources.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solution: a salt cavern gravity compressed air energy storage system, comprising:

[0005] A salt cavern, wherein a sealing film is provided on the inner side wall of the salt cavern, and the sealing film divides the salt cavern into two parts, a water storage chamber and an air storage chamber, wherein one end of an air pipe is connected to the bottom of the air storage chamber, and the other end of the air pipe is connected in parallel to an air compressor unit and an expansion generator unit;

[0006] A vertical shaft, the vertical shaft is vertically set up and connects the water storage chamber of the salt cavern with the ground surface, and a piston is arranged in the vertical shaft, and a gravity block is arranged on the top of the piston;

[0007] A water reservoir is placed above the salt cavern so that a height difference is formed between the water reservoir and the water storage cavity of the salt cavern. A water pipe communicating with the water storage cavity is arranged at the bottom of the water reservoir, and a hydraulic generator set is arranged on the water pipe.

[0008] In the aforementioned salt cavern gravity compressed air energy storage system, valves are provided at the connection ends of the air compressor unit and the expansion generator unit with the air pipe.

[0009] In the aforementioned salt cavern gravity compressed air energy storage system, a valve is provided on the water pipe.

[0010] The aforementioned salt cavern gravity compressed air energy storage system, the salt cavern side wall is provided with a mounting groove, the upper seal and the lower seal are inserted into the mounting groove, the end of the sealing film is clamped between the upper seal and the lower seal, the mounting groove is filled and cast with a filling part, and the filling part fixes the seal and the lower seal in the mounting groove.

[0011] In the aforementioned salt cavern gravity compressed air energy storage system, the contact surface between the upper seal and the lower seal is provided with a circular groove, a membrane frame is provided in the circular groove, and the end of the sealing membrane is folded and wrapped around the surface of the membrane frame.

[0012] In the aforementioned salt cavern gravity compressed air energy storage system, the filling portion comprises a foaming expansion layer and a sealing casting layer, and the foaming expansion layer is disposed inside the sealing casting layer.

[0013] In the aforementioned salt cavern gravity compressed air energy storage system, the top of the gravity block extends out of the vertical shaft and is provided with a gravity regulating part, the interior of the gravity regulating part is a hollow structure that can be filled with other objects that can apply gravity, and the top of the gravity regulating part is connected to a lifting device.

[0014] In the aforementioned salt cavern gravity compressed air energy storage system, the inner wall of the vertical shaft is provided with an inner wall of a sealing cylinder.

[0015] In the aforementioned salt cavern gravity compressed air energy storage system, a guide device is provided on the inner side of the inner wall of the sealing cylinder, and the guide device is in contact with the side wall of the gravity block.

[0016] A salt cavern gravity compressed air energy storage method, which uses any of the above-mentioned salt cavern gravity compressed air energy storage systems, includes the following process:

[0017] Fill the water source into the water reservoir, open the valve to allow the water to flow into the water storage cavity above the sealing membrane by its own gravity;

[0018] When storing energy, the air compressor unit pressurizes the air into the air storage chamber under the sealing membrane, and gradually pushes the water in the water storage chamber back to the water reservoir through the gas pressure, and at the same time lifts the piston and the gravity block. After the water reservoir reaches a certain height, the water valve is closed, and a certain amount of water remains in the water storage chamber. Air is continuously pressed into the air storage chamber to lift the gravity block until the maximum threshold set for energy storage is reached.

[0019] When releasing energy, compressed air is released into the expansion generator set to generate electricity. At the same time, the water valve is opened, the gravity block presses down the piston by its own gravity, and the water pressure in the water reservoir continuously presses the air in the air storage chamber to generate electricity. When the water in the water reservoir flows into the water storage chamber by its own gravity, the hydraulic generator set generates electricity synchronously.

[0020] Compared with the prior art, the present invention adopts liquid gravity in combination with salt cavern gas storage. The liquid can adapt to the irregular shape of the salt cavern, reduce construction and increase energy density. Surface construction can reduce the difficulty of construction. At the same time, other loads such as metal and cement counterweights can be adapted on the surface to increase gravity pressure, improve energy storage density and reduce counterweight volume. The present invention not only solves the problem of high investment cost of traditional compressed air energy storage systems, but also solves the problem of reusing salt cavern resources, and has good economic and environmental benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the system structure of the present invention;

[0022] Figure 2 It is a schematic diagram of the sealing film installation structure of the present invention;

[0023] Figure 3 It is a schematic diagram of the shaft structure of the present invention.

[0024] Figure numerals: 1-salt cave, 2-sealing membrane, 3-water storage chamber, 4-air storage chamber, 5-vertical shaft, 6-piston, 7-gravity block, 8-water reservoir, 9-water pipe, 10-hydraulic generator set, 11-air pipe, 12-air compressor set, 13-expansion generator set, 14-installing groove, 15-upper seal, 16-lower seal, 17-filling part, 18-circular groove, 19-membrane skeleton, 20-foaming expansion layer, 21-sealing casting layer, 22-gravity adjustment part, 23-inner wall of sealing cylinder, 24-guide device.

[0025] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. DETAILED DESCRIPTION

[0026] Embodiment 1 of the present invention: A salt cavern gravity compressed air energy storage system comprises: a salt cavern 1, using an abandoned salt cavern 1 with good sealing performance as an energy storage structure, a vertical shaft 5 is vertically opened on the top of the salt cavern 1, and an existing tunnel can also be used for transformation, the vertical shaft 5 is connected to the ground surface, and a sealing membrane 2 is arranged on the side wall of the inner cavity of the salt cavern 1, and the sealing membrane 2 divides the salt cavern 1 into two upper and lower parts, namely, a water storage chamber 3 and an air storage chamber 4, and one end of an air pipe 11 is connected to the bottom of the air storage chamber 4, and the other end of the air pipe 11 is connected in parallel with an air compressor unit 12 and an expansion generator unit 13, the vertical shaft 5 is vertically established and connects the water storage chamber 3 of the salt cavern 1 with the ground surface, and a piston 6 is arranged in the vertical shaft 5, and a gravity block 7 is arranged on the top of the piston 6, a water reservoir 8 is excavated on the ground surface, and a waterproof structure is laid, the water reservoir 8 is placed above the salt cavern 1, so that the water reservoir 8 forms a height difference with the water storage chamber 3 of the salt cavern 1, and a water pipe 9 connected to the water storage chamber 3 is arranged at the bottom of the water reservoir 8, and a hydraulic generator unit 10 is arranged on the water pipe 9.

[0027] Embodiment 2 of the present invention: A salt cavern gravity compressed air energy storage system, comprising: a salt cavern 1, using an abandoned salt cavern 1 with good sealing performance as an energy storage structure, a vertical shaft 5 is vertically opened on the top of the salt cavern 1, and an existing tunnel can also be used for transformation, the vertical shaft 5 is connected to the ground surface, and a sealing membrane 2 is provided on the inner side wall of the salt cavern 1, and the sealing membrane 2 divides the salt cavern 1 into two upper and lower parts, a water storage chamber 3 and an air storage chamber 4, and the bottom of the air storage chamber 4 is connected to one end of an air pipe 11, and the other end of the air pipe 11 is connected in parallel to an air compressor unit 12 and an expansion generator unit 13, and the vertical shaft 5 is vertically set up and connected to the water storage chamber 3 of the salt cavern 1. The cavity 3 is connected to the ground surface, and a piston 6 is arranged in the vertical shaft 5, and a gravity block 7 is arranged on the top of the piston 6. A water reservoir 8 is excavated on the ground surface, and a waterproof structure is laid. The water reservoir 8 is placed above the salt cavern 1, so that a height difference is formed between the water reservoir 8 and the water storage cavity 3 of the salt cavern 1. A water pipe 9 connected to the water storage cavity 3 is arranged at the bottom of the water reservoir 8, and a hydraulic generator set 10 is arranged on the water pipe 9, wherein valves are arranged at the connecting ends of the air compressor set 12 and the expansion generator set 13 and the air pipe 11, and valves are also arranged on the water pipe 9, and the valves are all electrically controlled valves and connected to the external control system.

[0028] Specifically, the side wall of the salt cavern 1 is provided with a mounting groove 14, in which an upper sealing member 15 and a lower sealing member 16 are inserted, and the end of the sealing membrane 2 is clamped between the upper sealing member 15 and the lower sealing member 16, and the mounting groove 14 is filled and cast with a filling portion 17, and the filling portion 17 fixes the sealing member 15 and the lower sealing member 16 in the mounting groove 14, and a circular groove 18 is provided on the contact surface between the upper sealing member 15 and the lower sealing member 16, and a membrane skeleton 19 is provided in the circular groove 18, and the end of the sealing membrane 2 is folded and wrapped around the surface of the membrane skeleton 19, and the filling portion 17 includes a foaming expansion layer 20 and a sealing casting layer 21, and the foaming expansion layer 20 is placed inside the sealing casting layer 21. During construction, the mounting groove 14 is designed according to the shape of the salt cavern 1 to surround the side wall of the salt cavern 1 and approximate The upper seal 15 and the lower seal 16 are of regular shape, and the upper seal 15 and the lower seal 16 are manufactured according to the shape surrounded by the installation groove 14. If necessary, an assembled structure can be adopted for easy installation. The membrane frame 19 is made of flexible metal and has a smooth surface. First, the upper seal 15 and the lower seal 16 are placed in the installation groove 14, and the end of the sealing membrane 2 is folded and wrapped around the surface of the membrane frame 19, and the membrane frame 19 is placed in the circular groove 18, and the upper seal 15 and the lower seal 16 are pressed tightly. The upper and lower gaps of the seal 15 and the lower seal 16 are filled in the installation groove 14 with an expansion agent, such as foaming glue, etc., and the expansion agent is waited for to expand and squeeze the upper seal 15 and the lower seal 16 and solidify, and then the sealing material is cast in the remaining space of the installation groove 14, such as casting modified concrete and applying waterproof sealing paint.

[0029] Specifically, the top of the gravity block 7 extends out of the vertical shaft 5 and is provided with a gravity adjusting part 22. The interior of the gravity adjusting part 22 is a hollow structure and can be filled with other objects that can apply gravity. The top of the gravity adjusting part 22 is connected to a lifting device, and other loads, such as metal or cement counterweights, can be adapted in the gravity adjusting part 22 to increase gravity pressure, improve energy storage density, and reduce counterweight volume.

[0030] Specifically, the inner wall of the shaft 5 is provided with a sealing cylinder inner wall 23 , and the inner side of the sealing cylinder inner wall 23 is provided with a guide device 24 , and the guide device 24 is in contact with the side wall of the gravity block 7 .

[0031] Embodiment 3 of the present invention: A salt cavern gravity compressed air energy storage method, which uses any of the salt cavern gravity compressed air energy storage systems described above, and includes the following process:

[0032] Fill the water source into the water reservoir 8, open the valve to allow the water to flow into the water storage chamber 3 above the sealing membrane 2 by its own gravity;

[0033] When storing energy, the air compressor unit 12 pressurizes the air into the air storage chamber 4 below the sealing membrane 2, and gradually pushes the water in the water storage chamber 3 back to the water reservoir 8 through the gas pressure, and at the same time, the piston 6 and the gravity block 7 are lifted up. After the water reservoir 8 reaches a certain height, the water valve is closed, and a certain amount of water is retained in the water storage chamber 3. Air is continuously pressed into the air storage chamber 4 to lift the gravity block 7 until the maximum threshold set for energy storage is reached;

[0034] When releasing energy, the compressed air is released into the expansion generator set 13 to generate electricity. At the same time, the water valve is opened, the gravity block 7 presses down the piston 6 by its own gravity, and the water pressure in the water reservoir 8 continuously pressurizes the air in the air storage chamber 4 to generate electricity. When the water in the water reservoir 8 flows into the water storage chamber 3 by its own gravity, the hydraulic generator set 10 generates electricity synchronously.

[0035] Working principle of an embodiment of the present invention: The present invention has two working states during use: energy storage and energy release, wherein:

[0036] When storing energy, the air compressor unit 12 pressurizes the air into the air storage chamber 4 below the sealing membrane 2, and gradually pushes the water in the water storage chamber 3 back to the water reservoir 8 through the gas pressure, and at the same time, the piston 6 and the gravity block 7 are lifted up. After the water reservoir 8 reaches a certain height, the water valve is closed, and a certain amount of water is retained in the water storage chamber 3. Air is continuously pressed into the air storage chamber 4 to lift the gravity block 7 until the maximum threshold set for energy storage is reached;

[0037] When releasing energy, the compressed air is released into the expansion generator set 13 to generate electricity. At the same time, the water valve is opened, the gravity block 7 presses down the piston 6 by its own gravity, and the water pressure in the water reservoir 8 continuously pressurizes the air in the air storage chamber 4 to generate electricity. When the water in the water reservoir 8 flows into the water storage chamber 3 by its own gravity, the hydraulic generator set 10 generates electricity synchronously.

Claims

1. A salt cavern gravity compressed air energy storage system, characterized in that: include: A salt cavern (1), wherein a sealing membrane (2) is provided on the inner side wall of the salt cavern (1), wherein the sealing membrane (2) divides the salt cavern (1) into two upper and lower parts, namely a water storage chamber (3) and an air storage chamber (4), wherein the bottom of the air storage chamber (4) is connected to one end of an air pipe (11), and the other end of the air pipe (11) is connected in parallel to an air compressor unit (12) and an expansion generator unit (13); A vertical shaft (5), the vertical shaft (5) is vertically set up and connects the water storage chamber (3) of the salt cavern (1) with the ground surface, and a piston (6) is arranged in the vertical shaft (5), and a gravity block (7) is arranged on the top of the piston (6); A water reservoir (8), the water reservoir (8) being placed above the salt cavern (1) so that a height difference is formed between the water reservoir (8) and the water storage chamber (3) of the salt cavern (1), a water pipe (9) communicating with the water storage chamber (3) being arranged at the bottom of the water reservoir (8), and a water conservancy generator set (10) being arranged on the water pipe (9).

2. A salt cavern gravity compressed air energy storage system according to claim 1, characterized in that: The connection ends of the air compressor unit (12) and the expansion generator unit (13) with the air pipe (11) are all provided with valves.

3. A salt cavern gravity compressed air energy storage system and method according to claim 1, characterized in that: The water pipe (9) is provided with a valve.

4. The salt cavern gravity compressed air energy storage system according to claim 1, characterized in that: The side wall of the salt cavern (1) is provided with a mounting groove (14), an upper sealing member (15) and a lower sealing member (16) are inserted into the mounting groove (14), an end portion of the sealing membrane (2) is clamped between the upper sealing member (15) and the lower sealing member (16), the mounting groove (14) is filled and cast with a filling portion (17), and the filling portion (17) fixes the sealing member (15) and the lower sealing member (16) in the mounting groove (14).

5. A salt cavern gravity compressed air energy storage system according to claim 4, characterized in that: A circular groove (18) is provided on the contact surface between the upper sealing member (15) and the lower sealing member (16), a membrane skeleton (19) is provided in the circular groove (18), and the end of the sealing membrane (2) is folded and wrapped around the surface of the membrane skeleton (19).

6. A salt cavern gravity compressed air energy storage system according to claim 4 or 5, characterized in that: The filling portion (17) comprises a foaming expansion layer (20) and a sealing casting layer (21), wherein the foaming expansion layer (20) is disposed inside the sealing casting layer (21).

7. The salt cavern gravity compressed air energy storage system according to claim 1, characterized in that: The top end of the gravity block (7) extends out of the vertical shaft (5) and is provided with a gravity adjustment part (22). The interior of the gravity adjustment part (22) is a hollow structure and can be filled with other objects that can apply gravity. The top end of the gravity adjustment part (22) is connected to a lifting device.

8. A salt cavern gravity compressed air energy storage system according to claim 1 or 7, characterized in that: The inner side wall of the vertical shaft (5) is provided with an inner wall of a sealing cylinder (23).

9. The salt cavern gravity compressed air energy storage system according to claim 8, characterized in that: A guide device (24) is provided on the inner side of the inner wall (23) of the sealing cylinder, and the guide device (24) is in contact with the side wall of the gravity block (7).

10. A salt cavern gravity compressed air energy storage method, which adopts the salt cavern gravity compressed air energy storage system according to any one of claims 1 to 9, characterized in that: The process includes the following: Fill the water source into the water reservoir (8), open the valve to allow the water to flow into the water storage chamber (3) above the sealing membrane (2) by its own gravity; When storing energy, the air compressor unit (12) pressurizes air into the air storage chamber (4) below the sealing membrane (2), and gradually pushes the water in the water storage chamber (3) back to the water reservoir (8) through the gas pressure, and at the same time, the piston (6) and the gravity block (7) are lifted up. After the water reservoir (8) reaches a certain height, the water valve is closed to retain a certain amount of water in the water storage chamber (3), and air is continuously pressed into the air storage chamber (4) to lift the gravity block (7) until the maximum threshold set for energy storage is reached; When releasing energy, the compressed air is released into the expansion generator set (13) to generate electricity. At the same time, the water valve is opened, the gravity block (7) presses down the piston (6) by its own weight, and the water pressure in the water reservoir (8) continuously presses the air in the air storage chamber (4) to generate electricity. When the water in the water reservoir (8) flows into the water storage chamber (3) by its own weight, the hydraulic generator set (10) generates electricity synchronously.

Images