Device and method for testing permeability coefficient of flexible sealing material of compressed air energy storage underground cavern

Abstract

The invention discloses a compressed air energy storage underground cavern flexible sealing material permeability coefficient testing device which comprises an air compressor, a booster pump, an air storage tank, a high-pressure sealing box and a micro-gas measuring device, the high-pressure sealing box comprises an upper pressing plate and a lower pressing plate, and a permeable stone plate is horizontally placed in a first groove in the top of the lower pressing plate; a second groove in the bottom of the upper pressing plate serves as an air pressure chamber on the high-pressure side, an air inlet hole and an air outlet hole are formed in the upper pressing plate and the lower pressing plate respectively, an air inlet valve is installed on a first pipeline between the air inlet hole and the air storage tank, and the first pipeline is connected with an air outlet valve; the air outlet hole is connected with a first beaker, the first beaker is connected with a second beaker, and the second beaker is placed on a high-precision electronic balance. The testing device and method are safe, reliable and convenient to operate, high-precision testing of the permeability coefficient of the flexible sealing material can be achieved, and the blank of an existing permeability coefficient testing device and method under the high-internal-pressure working condition is filled up.

Description

Technical Field

[0001] The present invention relates to the field of underground energy storage, and in particular to a device and method for testing the permeability coefficient of flexible sealing materials of compressed air energy storage underground caverns. Background Art

[0002] Due to the intermittent and volatile characteristics of renewable energy, direct large-scale grid connection will bring a huge impact to the power grid, so corresponding energy storage technology is needed. Compressed air energy storage (i.e. compressed air energy storage) is one of the few large-scale energy storage technologies and has urgent and huge development potential in areas of my country rich in renewable energy.

[0003] As a storage container for high-pressure air, underground caverns play an important role in the operation of compressed gas energy storage power stations, and the key issue in their construction is the sealing of the caverns. Flexible sealing materials are a promising sealing material for compressed gas energy storage underground caverns due to their advantages of low cost, good airtightness, and strong geological adaptability. Commonly used flexible sealing materials include butyl rubber, nitrile rubber, EPDM rubber, etc. However, flexible sealing materials have a certain permeability. Therefore, when designing the airtightness of flexible sealed compressed gas energy storage caverns, it is first necessary to determine the size of the permeability coefficient of the flexible sealing material. At present, the commercial test device for the permeability coefficient of flexible sealing materials is only applicable to low internal pressure conditions (usually the maximum air pressure is 0.1MPa), and there is no corresponding device and method for the determination of the permeability coefficient under high internal pressure conditions. Summary of the invention

[0004] In view of the difficulty in testing the permeability coefficient of flexible sealing materials under high internal pressure conditions, the present invention provides a safe, reliable and easy-to-operate device and method for testing the permeability coefficient of flexible sealing materials in compressed air energy storage underground caverns, which can achieve high-precision testing of the permeability coefficient of flexible sealing materials and fill the gap in existing devices and methods for testing the permeability coefficient of flexible sealing materials under high internal pressure conditions.

[0005] The technical solution adopted by the present invention to solve the above-mentioned technical problems is: a permeability coefficient testing device for flexible sealing materials of compressed air energy storage underground caverns, including an air compressor, a booster pump, an air storage tank, a high-pressure sealing box and a micro-gas measuring device, the high-pressure sealing box is set in a water bath, the high-pressure sealing box includes an upper pressing plate and a lower pressing plate, the top of the lower pressing plate is provided with a first groove, a permeable stone slab is placed flat in the first groove, the top surface of the permeable stone slab is flush with the top surface of the lower pressing plate, the bottom of the upper pressing plate is provided with a second groove with a height greater than or equal to 1 cm, the second groove serves as an air pressure chamber on the high-pressure side, an air inlet hole communicating with the air pressure chamber is vertically opened on the upper pressing plate, an air outlet hole is vertically opened on the lower pressing plate, the air inlet hole is directly connected to the bottom surface of the permeable stone slab, the air inlet hole is connected to the air storage tank via a first pipeline, an air inlet valve is installed on the first pipeline and is connected to an air outlet valve, the micro-gas The volume measurement device includes a first beaker, a second beaker and a high-precision electronic balance scale. The first beaker is filled with water, the mouth of the first beaker is sealed by a rubber stopper, the air outlet is connected to the first beaker via a second pipeline, one end of the second pipeline is passed through the rubber stopper and is located above the liquid level in the first beaker, the first beaker is connected to the second beaker via a third pipeline, one end of the third pipeline is passed through the rubber stopper and is located below the liquid level in the first beaker, the other end of the third pipeline extends into the second beaker, the mouth of the second beaker is open, and the second beaker is placed on the high-precision electronic balance scale. Before testing, a sheet-like flexible sealing material specimen is laid flat to cover the permeable stone slab, and then the upper pressing plate is pressed and fixed on the lower pressing plate, the flexible sealing material specimen is pressed by the upper pressing plate to seal the air pressure chamber, and then the test can be started.

[0006] Preferably, the upper pressing plate is fixedly connected to the lower pressing plate by a plurality of bolts, and a convex ring protruding downward is integrally provided at the bottom of the upper pressing plate, and the inner diameter of the convex ring is larger than the diameter of the flexible sealing material specimen, and the convex ring is used to press the flexible sealing material specimen after the upper pressing plate is fixedly connected to the lower pressing plate to seal the air pressure chamber. The flexible sealing material specimen is pressed by the convex ring at the bottom of the upper pressing plate to achieve the sealing of the air pressure chamber on the high-pressure side, which has simple structure and operation, low cost, and is safe and reliable.

[0007] The technical principle of the present invention is as follows: 1) an air compressor and a booster pump are used as air sources. During the test, the air is continuously compressed to a specified pressure and stored in an air storage tank, so as to provide the required high-pressure air for the high-pressure sealing box; 2) the high-pressure sealing box presses the flexible sealing material specimen through an upper pressure plate to realize the sealing of the high-pressure side air pressure chamber. At the same time, the high-pressure sealing box replaces the low-pressure side air pressure chamber of the traditional sealing box with a permeable stone plate of a certain thickness, so as to prevent the flexible sealing material specimen from falling into the air outlet hole on the low-pressure side under the action of the high gas internal pressure, wherein the part above the flexible sealing material specimen is the high-pressure side, and the part below the permeable stone plate is the low-pressure side; 3) the high-temperature environment required for the test is realized by water bath heating in a water bath; 4) the high-pressure air in the air pressure chamber drives the water in the first beaker to enter the second beaker after passing through the flexible sealing material specimen, and the mass change of the water replaced by the air in the second beaker is recorded by a high-precision electronic balance scale. Finally, when the mass change rate of the water replaced by the air remains constant, the permeability coefficient of the flexible sealing material specimen is calculated inversely according to the mass change rate of the water in the second beaker in the stable stage.

[0008] The permeability coefficient testing method of the flexible sealing material of the compressed air energy storage underground cavern implemented by the permeability coefficient testing device comprises the following steps:

[0009] (1) Place the sheet-like flexible sealing material specimen flat on the permeable stone plate and press the upper pressing plate onto the lower pressing plate, then fill the water bath with water and heat the water bath to the test temperature;

[0010] (2) Turn on the high-precision electronic balance and perform the tare operation;

[0011] (3) Close the air inlet valve and the air outlet valve, and continuously compress the air to the specified pressure through the air compressor and the booster pump and store it in the air tank;

[0012] (4) When the gas storage tank is filled with gas, adjust the air inlet valve to adjust the gas pressure in the pressure chamber to the test pressure;

[0013] (5) Wait for a while and record the change in the mass of water displaced by the air in the second beaker using a high-precision electronic balance until the mass change rate of the displaced water remains constant. Substitute the change into the permeability coefficient calculation formula to obtain the permeability coefficient of the flexible sealing material specimen under the test temperature and test pressure.

[0014] Specifically, the calculation formula of the permeability coefficient is:

[0015]

[0016] Where: κ is the permeability coefficient of the flexible sealing material specimen, unit is (m 3 ·(STP)·m) / (m 2·s·Pa); Q is the gas volume flow rate through the flexible sealing material specimen, in m 3 ; t is the penetration time, in seconds; d is the thickness of the flexible sealing material specimen, in meters; ΔP is the pressure difference between the two ends of the flexible sealing material specimen, in Pa; A is the air permeability area of ​​the flexible sealing material specimen, in meters 2 ;

[0017] From the gas state equation, we can know that the gas flow rate entering the first beaker is:

[0018]

[0019] Where: is the gas flow rate of the gas entering the first beaker, in m 3 / s; is the volume flow rate of gas flowing out of the high pressure sealing box, in m 3 / s;T s is the room temperature, in K; T is the temperature of the gas in the micro gas measurement device, in K;

[0020] The volume flow rate of water displaced by air in the second beaker is:

[0021]

[0022] Where: is the volume flow rate of water displaced by air in the second beaker, in m 3 / s; is the rate of change of mass of water displaced by air in the second beaker, in kg / s; ρ w is the density of the water displaced by the air in the second beaker, in kg / m 3 ;

[0023] The volume flow rate of water displaced by air in the second beaker is equal to the gas flow rate of gas entering the first beaker, that is, Combining equations (1), (2) and (3), we can obtain:

[0024]

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] 1. The device and method for testing the permeability coefficient of flexible sealing materials for compressed gas energy storage underground caverns of the present invention are safe, reliable, easy to operate, and can achieve high-precision testing of the permeability coefficient of flexible sealing materials, thus filling the gap in the existing device and method for testing the permeability coefficient of flexible sealing materials under high internal pressure conditions;

[0027] 2. The micro-gas measuring device designed by the present invention can monitor the trace gas in real time, overcoming the shortcomings of the existing testing device, such as the difficulty of manual reading and poor accuracy caused by the long time of high-pressure penetration test;

[0028] 3. Different from the existing test device which uses a high-pressure gas cylinder as the gas source, the test device of the present invention uses an air compressor and a booster pump as the gas source, which can supply gas in real time and continuously according to the test requirements, and has the advantages of long duration and stable pressure;

[0029] 4. The present invention limits the height of the air pressure chamber on the high-pressure side, so as to avoid the flexible sealing material specimen blocking the air inlet under the action of high pressure, thereby increasing the penetration area of ​​the flexible sealing material specimen in the air pressure chamber and reducing the adverse effects of some environmental factors on the test results during the test. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of the structural connection of the permeability test device in Example 1 (upper pressing plate opened);

[0031] Figure 2 for Figure 1 Enlarged view of point A in the middle;

[0032] The specific reference numerals in the figure are as follows:

[0033] 1-air compressor; 2-boosting pump; 3-air storage tank; 4-inlet valve; 5-exhaust valve; 6-high-pressure sealing box; 7-water bath; 8-micro gas measuring device; 9-rubber stopper; 10-first beaker; 11-second beaker; 12-high-precision electronic balance; 13-bolt; 14-second groove; 15-upper pressure plate; 16-flexible sealing material specimen; 17-permeable stone slab; 18-lower pressure plate, 19-first groove, 20-inlet hole, 21-exhaust hole, 22-first pipeline, 23-second pipeline, 24-third pipeline, 25-convex ring. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below in conjunction with the embodiments of the drawings. The devices, equipment or components not limited in the present invention all adopt conventional technical means in the art.

[0035] Embodiment 1: A device for testing the permeability coefficient of flexible sealing materials for compressed air energy storage underground caverns, such as Figure 1 and Figure 2As shown, it includes an air compressor 1, a booster pump 2, an air storage tank 3, a high-pressure sealed box 6 and a micro-gas measuring device 8. The high-pressure sealed box 6 is set in a water bath 7. The high-pressure sealed box 6 includes an upper pressing plate 15 and a lower pressing plate 18. The top of the lower pressing plate 18 is provided with a first groove 19. A permeable stone plate 17 is placed flat in the first groove 19. The top surface of the permeable stone plate 17 is flush with the top surface of the lower pressing plate 18. The bottom of the upper pressing plate 15 is provided with a second groove 14 with a height of 1 cm. The second groove 14 serves as an air pressure chamber on the high-pressure side. An air inlet 20 communicating with the air pressure chamber is vertically opened on the upper pressing plate 15, and an air outlet 21 is vertically opened on the lower pressing plate 18. The air outlet 21 is directly connected to the bottom surface of the permeable stone plate 17. The air inlet 20 is connected to the air storage tank 3 through a first pipeline 22. An air inlet valve 4 is installed on the first pipeline 22 and is connected to an air outlet valve 5. The micro-gas measuring device 8 includes a first beaker 10, a second beaker 11 and a high-precision electronic balance scale 12. The first beaker 10 is filled with water, and the mouth of the first beaker 10 is sealed by a rubber stopper 9. The air outlet 21 is connected to the first beaker 10 via a second pipeline 23. One end of the second pipeline 23 is penetrated through the rubber stopper 9 and is located above the liquid level in the first beaker 10. The first beaker 10 is connected to the second beaker 11 via a third pipeline 24. One end of the third pipeline 24 is penetrated through the rubber stopper 9 and is located below the liquid level in the first beaker 10. The other end of the third pipeline 24 extends into the second beaker 11. The mouth of the second beaker 11 is open, and the second beaker 11 is placed on the high-precision electronic balance scale 12.

[0036] Specifically, the upper pressure plate 15 is fixedly connected to the lower pressure plate 18 by a plurality of bolts 13. A downwardly protruding convex ring 25 is integrally provided at the bottom of the upper pressure plate 15. The inner diameter of the convex ring 25 is larger than the diameter of the flexible sealing material specimen 16. The convex ring 25 is used to press the flexible sealing material specimen 16 after the upper pressure plate 15 is fixedly connected to the lower pressure plate 18 to seal the air pressure chamber.

[0037] Embodiment 2: A method for testing the permeability coefficient of a flexible sealing material for a compressed air energy storage underground cavern implemented using the permeability coefficient testing device of Embodiment 1 comprises the following steps:

[0038] (1) A sheet-like flexible sealing material specimen (a butyl rubber sheet with a thickness of 3 to 10 mm is used as the flexible sealing material specimen in this embodiment) is laid flat and covered with a permeable stone plate, and then an upper pressing plate is placed on the lower pressing plate, and several bolts are tightened. The convex ring at the bottom of the upper pressing plate is used to press the flexible sealing material specimen to achieve the sealing of the high-pressure side air pressure chamber, and then a water bath is filled with water and the water bath is heated to the test temperature;

[0039] (2) Turn on the high-precision electronic balance and perform the tare operation;

[0040] (3) Close the air inlet valve and the air outlet valve, and continuously compress the air to the specified pressure through the air compressor and the booster pump and store it in the air tank;

[0041] (4) When the gas storage tank is filled with gas, adjust the air inlet valve to adjust the gas pressure in the pressure chamber to the test pressure;

[0042] (5) Wait for a while and record the change in the mass of water replaced by air in the second beaker by a high-precision electronic balance until the mass change rate of the replaced water remains constant. Substitute it into the calculation formula of the permeability coefficient to obtain the permeability coefficient of the flexible sealing material specimen under the test temperature and test pressure, where:

[0043] The calculation formula of permeability coefficient is:

[0044]

[0045] Where: κ is the permeability coefficient of the flexible sealing material specimen, unit is (m 3 ·(STP)·m) / (m 2 ·s·Pa); Q is the gas volume flow rate through the flexible sealing material specimen, in m 3 ; t is the penetration time, in seconds; d is the thickness of the flexible sealing material specimen, in meters; ΔP is the pressure difference between the two ends of the flexible sealing material specimen, in Pa; A is the air permeability area of ​​the flexible sealing material specimen, in meters 2 ;

[0046] From the gas state equation, we can know that the gas flow rate entering the first beaker is:

[0047]

[0048] Where: is the gas flow rate of the gas entering the first beaker, in m 3 / s; is the volume flow rate of gas flowing out of the high pressure sealing box, in m 3 / s;T s is the room temperature, in K; T is the temperature of the gas in the micro gas measurement device, in K;

[0049] The volume flow rate of water displaced by air in the second beaker is:

[0050]

[0051] Where: is the volume flow rate of water displaced by air in the second beaker, in m 3 / s; is the rate of change of mass of water displaced by air in the second beaker, in kg / s; ρ wis the density of the water displaced by the air in the second beaker, in kg / m 3 ;

[0052] The volume flow rate of water displaced by air in the second beaker is equal to the gas flow rate of gas entering the first beaker, that is, Combining equations (1), (2) and (3), we can obtain:

[0053]

Claims

1. A device for testing the permeability coefficient of flexible sealing materials for compressed air energy storage underground caverns, characterized in that: The invention comprises an air compressor, a booster pump, an air storage tank, a high-pressure sealed box and a micro-gas measuring device. The high-pressure sealed box is mounted in a water bath. The high-pressure sealed box comprises an upper pressing plate and a lower pressing plate. The top of the lower pressing plate is provided with a first groove. A permeable stone plate is placed flat in the first groove. The top surface of the permeable stone plate is flush with the top surface of the lower pressing plate. The bottom of the upper pressing plate is provided with a second groove with a height greater than or equal to 1 cm. The second groove serves as an air pressure chamber on the high-pressure side. An air inlet hole communicating with the air pressure chamber is vertically opened on the upper pressing plate. An air outlet hole is vertically opened on the lower pressing plate. The air outlet hole is directly connected to the bottom surface of the permeable stone plate. The air inlet hole is connected to the air storage tank via a first pipeline. An air inlet valve is installed on the first pipeline and is connected to an air outlet valve. The micro-gas measuring device comprises a first beaker, a second beaker and a high-precision electronic The first beaker is filled with water, the mouth of the first beaker is sealed by a rubber stopper, the air outlet is connected to the first beaker via a second pipeline, one end of the second pipeline is passed through the rubber stopper and is located above the liquid level in the first beaker, the first beaker is connected to the second beaker via a third pipeline, one end of the third pipeline is passed through the rubber stopper and is located below the liquid level in the first beaker, the other end of the third pipeline extends into the second beaker, the mouth of the second beaker is open, and the second beaker is placed on the high-precision electronic balance scale. Before testing, a sheet-like flexible sealing material specimen is laid flat to cover the permeable stone slab, and then the upper pressing plate is pressed and fixed on the lower pressing plate, the flexible sealing material specimen is pressed by the upper pressing plate to seal the air pressure chamber, and then the test can be started.

2. The device for testing the permeability coefficient of flexible sealing materials for compressed air energy storage underground caverns according to claim 1 is characterized in that: The upper pressure plate is fixedly connected to the lower pressure plate by a plurality of bolts. A downwardly protruding convex ring is integrally provided at the bottom of the upper pressure plate. The inner diameter of the convex ring is larger than the diameter of the flexible sealing material specimen. The convex ring is used to press the flexible sealing material specimen after the upper pressure plate is fixedly connected to the lower pressure plate to seal the air pressure chamber.

3. A method for testing the permeability coefficient of flexible sealing materials for compressed air energy storage underground caverns using the permeability coefficient testing device according to claim 1 or 2, characterized in that: The following steps are involved: (1) Place the sheet-like flexible sealing material specimen flat on the permeable stone plate and press the upper pressing plate onto the lower pressing plate, then fill the water bath with water and heat the water bath to the test temperature; (2) Turn on the high-precision electronic balance and perform the tare operation; (3) Close the air inlet valve and the air outlet valve, and continuously compress the air to the specified pressure through the air compressor and the booster pump and store it in the air tank; (4) When the gas storage tank is filled with gas, adjust the air inlet valve to adjust the gas pressure in the pressure chamber to the test pressure; (5) Wait for a while and record the change in the mass of water displaced by the air in the second beaker using a high-precision electronic balance until the mass change rate of the displaced water remains constant. Substitute the change into the permeability coefficient calculation formula to obtain the permeability coefficient of the flexible sealing material specimen under the test temperature and test pressure.

4. The method for testing the permeability coefficient of flexible sealing materials for compressed air energy storage underground caverns according to claim 3 is characterized in that: The calculation formula of permeability coefficient is: Where: κ is the permeability coefficient of the flexible sealing material specimen, unit is (m 3 ·(STP)·m) / (m 2 ·s·Pa); Q is the gas volume flow rate through the flexible sealing material specimen, in m 3 ; t is the penetration time, unit is s; d is the thickness of the flexible sealing material specimen, in m; ΔP is the pressure difference between the two ends of the flexible sealing material specimen, in Pa; A is the air permeability area of ​​the flexible sealing material specimen, in m 2 ; From the gas state equation, we can know that the gas flow rate entering the first beaker is: Where: is the gas flow rate of the gas entering the first beaker, in m 3 / s; is the volume flow rate of gas flowing out of the high pressure sealing box, in m 3 / s;T s is the room temperature, in K; T is the temperature of the gas in the micro gas measurement device, in K; The volume flow rate of water displaced by air in the second beaker is: Where: is the volume flow rate of water displaced by air in the second beaker, in m 3 / s; is the rate of change of mass of water displaced by air in the second beaker, in kg / s; ρ w is the density of the water displaced by the air in the second beaker, in kg / m 3 ; The volume flow rate of water displaced by air in the second beaker is equal to the gas flow rate of gas entering the first beaker, that is, Combining equations (1), (2) and (3), we can obtain:

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