Damage identification method for flexible sealing layer of compressed air energy storage underground cavern

Abstract

The invention discloses a compressed air energy storage underground cavern flexible sealing layer damage identification method in the field of new energy development and utilization, and the method comprises the steps: building a mapping relation F between a pore fracture evolution rule and a temperature change rule in an inflation and deflation state through a test mode; then acquiring the apparent damage of the cavern sealing layer on site by using three-dimensional laser scanning equipment so as to perform preliminary screening on damaged parts, observing the shallow damage of key parts by using infrared imaging equipment, performing fine screening on the damaged parts of the sealing layer, and detecting the temperature change rule of the finely screened parts of the sealing layer by using a temperature detector; and finally, comparing the actually detected data with the mapping relation F between the pore crack evolution rule and the temperature change rule so as to judge the reliability of the damaged part of the sealing layer. The whole identification process takes a pore crack evolution rule and a temperature change rule as judgment basis, and remote and long-time monitoring can be realized, so that theoretical support is provided for damage monitoring of the sealing layer.

Description

Technical Field

[0001] The present invention relates to the field of new energy development and utilization, and in particular to a method for identifying damage to a flexible sealing layer of an underground cavern for compressed air energy storage. Background Art

[0002] Energy storage technology is an important field that all countries are competing to develop. It has a special strategic position and is an important support for improving my country's energy structure. It has important research value. Among them, compressed air energy storage technology is regarded as another large-scale energy storage technology with great potential besides pumped storage, and has broad development prospects. For underground hard cavern compressed air energy storage, one of the research difficulties lies in the sealing of underground caverns. Initially, steel plate lining was mostly used in the project, but the cost was high. For this reason, the industry proposed the idea of ​​a flexible sealing layer, with the aim of achieving high-pressure gas sealing with reasonable economic investment.

[0003] However, the difficulty faced by the flexible sealing layer is that the flexible materials are still under continuous research and development or improvement. The existing flexible sealing layer materials may be damaged and cracked under the action of cyclic high pressure, causing the escape of high-pressure gas. Therefore, how to quickly identify and repair the flexible sealing layer is an inevitable issue. Due to the short development time of underground hard cavern compressed air energy storage systems, there are currently no reports on equipment and methods for hard cavern compressed air energy storage flexible sealing layers. The limitation of previous research is that there is no relatively mature theoretical method and system. Therefore, through a set of test and monitoring equipment, a theoretical model that can be applied to the crack information of the flexible sealing layer of the compressed storage cavern is established, which is applied to the on-site sealing layer damage detection, and based on this, the rapid repair of the flexible seal is realized, which has important practical significance. Summary of the invention

[0004] In order to make up for the gap in the existing technology in the monitoring of flexible sealing layer damage, the technical problem to be solved by the present invention is to provide a method for identifying damage of the flexible sealing layer of an underground cavern for compressed air energy storage.

[0005] The technical solution adopted by the present invention to solve its technical problem is:

[0006] The method for identifying damage of flexible sealing layer of compressed air energy storage underground cavern comprises the following steps:

[0007] Step 1: A cylindrical specimen is made by using a flexible sealing layer, and an inflation and deflation test is performed on the cylindrical specimen. During the test, a CT scanner is used to detect the cylindrical specimen, and the three-dimensional information of the cracks appearing on the cylinder wall is recorded. At the same time, a temperature measuring instrument is used to measure the temperature at the cracks;

[0008] Step 2: The fissure images obtained after CT scanning were binarized using matalb software and based on the Hausdorff fractal dimension formula The crack values ​​in the binary image are quantitatively obtained, and the crack quantitative values ​​are fitted with the measured temperature values ​​to obtain the mapping relationship F between the crack evolution law and the temperature change law, that is,

[0009] Step 3: When the cavern is inflated and deflated, use 3D laser scanning equipment to identify cracks on the surface of the sealing layer to conduct a preliminary screening of the damaged parts;

[0010] Step 4: After initially identifying the cracks on the surface of the sealing layer on site, use infrared imaging equipment to observe the shallow damage of the initial screening area to obtain the width and depth information of the suspected cracks. At the same time, use a temperature detector to measure the temperature of the suspected cracks. Then, under normal inflation and deflation conditions, the evolution law of the suspected cracks and the change law of the temperature are obtained;

[0011] Step 5: Compare and analyze the crack evolution law and temperature change law obtained in step 4 with the mapping relationship F in step 2 to determine the reliability of the suspected damaged part of the sealing layer on site.

[0012] Furthermore, the cylindrical specimen includes a flexible sealing layer rolled into a cylindrical shape, and steel cover plates covering the upper and lower ends of the flexible sealing layer, wherein the upper steel cover plate is provided with a through hole for the inflation and deflation steel pipe to pass through, an inflation pump is provided at the end of the inflation and deflation steel pipe away from the steel cover plate, and a dehumidifier is also provided in the middle of the inflation and deflation steel pipe.

[0013] Furthermore, the wall thickness of the cylindrical test piece is consistent with the thickness of the flexible sealing layer on site. When performing the inflation and deflation test, the inflation and deflation pressure is the same as the on-site inflation and deflation pressure value, which is 6-10Mpa.

[0014] Furthermore, when the sealing layer is tested on site in steps three and four, the three-dimensional laser scanner, infrared imaging equipment and temperature detector are first covered with transparent glass covers resistant to high temperature and high pressure, and then brought into the site for testing, while ensuring that the three devices are electrically connected to the computer command system.

[0015] Furthermore, when it is determined in step five that the reliability of the suspected damaged part of the sealing layer is low, the computer command system can control the high-pressure spraying system to carry out rapid temporary repairs on the suspected damaged part by high-pressure spraying of UHPC concrete and ECC concrete, and then replace it with the original flexible sealing layer material.

[0016] The beneficial effects of the present invention are as follows: firstly, a mapping relationship F between the evolution law of pores and cracks and the law of temperature change under the state of inflation and deflation is established by means of an experiment, which is used to lock the damaged part of the sealing layer on site, and then the apparent damage of the cavern sealing layer is obtained by a three-dimensional laser scanning device on site to conduct a preliminary screening of the damaged part, and the shallow damage of the key parts is observed by infrared imaging equipment to conduct a fine screening of the damaged part of the sealing layer, and the temperature change law of the finely screened part of the sealing layer is detected by a temperature detector, and finally the actual detected data is compared with the mapping relationship F between the evolution law of pores and cracks and the law of temperature change, so as to judge the reliability of the damaged part of the sealing layer. The entire identification process uses the evolution law of pores and cracks and the law of temperature change as the judgment basis, and can achieve long-distance and long-term monitoring, thereby providing theoretical support for damage monitoring of the sealing layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the on-site damage identification and repair principle of the present invention;

[0018] Figure 2 It is the principle diagram of the indoor test of the present invention.

[0019] Marked in the figure are, 1-cylindrical specimen, 2-on-site sealing layer, 3-three-dimensional laser scanning equipment, 4-infrared imaging equipment, 5-temperature detector, 6-transparent glass cover, 7-computer command system, 8-high-pressure spraying system, 11-flexible sealing layer, 12-steel cover, 13-inflating and deflating steel pipe, 14-inflating pump, 15-dehumidifier, 21-crack. DETAILED DESCRIPTION

[0020] The present invention is further described below in conjunction with the accompanying drawings.

[0021] It should be noted that if there are directional indication terms in the present invention, such as up, down, left, right, front, and back directions and orientation terms, they are for the purpose of facilitating the description of the relative position relationship between components, and are not specific to the absolute position of the related components or the position relationship between components. They are only used to explain the relative position relationship and movement of the components in a certain posture. If the specific posture changes, the directional indication will also change accordingly. If there are terms related to quantity in the present invention, such as "multiple", "multiple", "several", etc., they specifically refer to two or more.

[0022] like Figure 1 , Figure 2 As shown, the method for identifying damage to the flexible sealing layer of a compressed air energy storage underground cavern provided by the present invention comprises the following steps:

[0023] Step 1: a cylindrical test piece 1 is made by using a flexible sealing layer, and an inflation and deflation test is performed on the cylindrical test piece 1. During the test, a CT scanner is used to detect the cylindrical test piece 1, and the three-dimensional information of the cracks appearing on the cylinder wall is recorded. At the same time, a temperature measuring instrument is used to measure the temperature at the cracks;

[0024] Step 2: The fissure images obtained after CT scanning were binarized using matalb software and based on the Hausdorff fractal dimension formula The crack values ​​in the binary image are quantitatively obtained, and the crack quantitative values ​​are fitted with the measured temperature values ​​to obtain the mapping relationship F between the crack evolution law and the temperature change law, that is,

[0025] Step 3: When the on-site cavern is inflated and deflated, the cracks 21 on the surface of the on-site sealing layer 2 are identified using a three-dimensional laser scanning device 3 to perform a preliminary screening of the damaged parts;

[0026] Step 4: After initially identifying the cracks 21 on the surface of the sealing layer 2 at the scene, the infrared imaging device 4 is used to observe the shallow damage of the initial screening position to obtain the width and depth information of the suspected cracks, and the temperature detector 5 is used to measure the temperature of the suspected cracks. Then, the evolution law of the suspected cracks and the change law of the temperature are obtained under normal inflation and deflation conditions;

[0027] Step 5: Compare and analyze the crack evolution law and temperature change law obtained in step 4 with the mapping relationship F in step 2 to determine the reliability of the suspected damaged part of the sealing layer 2 on site.

[0028] Among them, steps one and two are mainly to obtain the relationship between the evolution law of the cracks and the temperature change law at the cracks during the inflation and deflation process through indoor tests. Because if there are through cracks on the flexible sealing layer 11, gas will inevitably pass through the cracks during the inflation and deflation process, which will cause the shape of the cracks to change. At the same time, the gas will take away some heat when passing through the cracks, so the temperature at the cracks will change; if the surface layer seems to have cracks, but does not penetrate the flexible sealing layer, the shape and temperature of the cracks will not change at the same time during the inflation and deflation process. Therefore, by establishing a mapping relationship F between the evolution law of the cracks during the inflation and deflation process and the temperature change law at the cracks, it is possible to determine whether it is a through crack by measuring the shape and temperature of the suspected cracks on site, thereby realizing the rapid identification of the damaged parts of the sealing layer 2 on site. Because underground energy storage caverns are large, and cracks are usually small, step three is mainly to preliminarily determine the location of suspected cracks through image recognition, and then use infrared imaging equipment to make a detailed description of the suspected damaged parts of the sealing layer, obtain information such as the width and depth of the suspected cracks, and use a temperature detector to measure the temperature of the suspected cracks. Finally, compare the field measured data with the mapping relationship F obtained indoors to draw a conclusion. For the judgment of on-site cracks, the measured data can be brought into the expression of the mapping relationship F for calculation, or the overlap of the two graphics can be compared by drawing graphics to obtain the reliability of the suspected damaged parts, that is, the probability or degree of crack penetration.

[0029] When conducting indoor tests and making the cylindrical test piece 1, the flexible sealing layer 11 can be first rolled into a cylindrical structure and firmly bonded, and then a steel cover plate 12 is placed on each of the upper and lower ends to form a cylindrical structure with sealed ends, wherein the upper steel cover plate 12 is provided with a through hole for the inflation and deflation steel pipe 13 to pass through, and an inflation pump 14 is provided at the end of the inflation and deflation steel pipe 13 away from the steel cover plate 12, and a dehumidifier 15 is also provided in the middle of the inflation and deflation steel pipe 13. The purpose of setting the dehumidifier 15 is to absorb moisture in the air, to prevent condensation from forming inside the test piece under the inflation and deflation state, which will have an adverse effect on the cylindrical test piece 1, and also to avoid affecting the crack temperature.

[0030] In order to better simulate the working conditions of the on-site sealing layer during indoor testing, the wall thickness of the cylindrical specimen 1 is preferably consistent with the thickness of the on-site sealing layer 2. When conducting inflation and deflation tests, the inflation and deflation pressures are also preferably the same as the on-site inflation and deflation pressures, which can be specifically controlled at 6-10Mpa.

[0031] Since the energy storage cavern is under high pressure and high temperature during operation, when testing the on-site sealing layer 2 in steps 3 and 4, the three-dimensional laser scanner 3, infrared imaging device 4 and temperature detector 5 can be covered with transparent glass covers 6 resistant to high temperature and high pressure, and then put into the site for testing, which can protect the measuring equipment. In addition, since the inspectors cannot stay in the energy storage cavern during operation, the three devices need to be electrically connected to the external computer command system 7 through wires, etc., to facilitate the observation and collection of data by the measuring personnel.

[0032] Furthermore, in order to achieve the monitoring purpose of early detection and early treatment, a high-pressure spraying system 8 can be set in the energy storage cavern. When the reliability of the suspected damaged part of the sealing layer is judged to be low in step 5, the computer command system 7 can control the high-pressure spraying system 8 to carry out high-pressure spraying of UHPC concrete and ECC concrete on the suspected damaged part for rapid temporary repair, and then replace it with the original flexible sealing layer material. Specifically, UHPC concrete can be sprayed first, and then ECC concrete can be sprayed to form external ECC concrete to resist strain and internal UHPC concrete to resist stress effect, so as to adapt to tensile deformation under high pressure. When the cavern is inspected and maintained later, the concrete can be removed and the flexible sealing material can be replaced.

Claims

1. A method for identifying damage to the flexible sealing layer of an underground cavern for compressed air energy storage, characterized in that: The following steps are involved: Step 1: A cylindrical test piece (1) is made by using a flexible sealing layer (11), and an inflation and deflation test is performed on the cylindrical test piece (1). During the test, a CT scanner is used to detect the cylindrical test piece (1), and three-dimensional information of cracks appearing on the cylinder wall is recorded. At the same time, a temperature measuring instrument is used to measure the temperature at the cracks; Step 2: The fissure images obtained after CT scanning were binarized using matalb software and based on the Hausdorff fractal dimension formula The crack values ​​in the binary image are quantitatively obtained, and the crack quantitative values ​​are fitted with the measured temperature values ​​to obtain the mapping relationship F between the crack evolution law and the temperature change law, that is, Step 3: When the on-site cavern is inflated and deflated, a three-dimensional laser scanning device (3) is used to identify cracks (21) on the surface of the on-site sealing layer (2) to conduct a preliminary screening of the damaged parts; Step 4: After initially identifying the cracks (21) on the surface of the sealing layer (2) at the scene, an infrared imaging device (4) is used to observe the shallow damage of the initial screening position to obtain the width and depth information of the suspected cracks, and at the same time, a temperature detector (5) is used to measure the temperature of the suspected cracks, and then the evolution law of the suspected cracks and the temperature change law are obtained under normal inflation and deflation conditions; Step 5: Compare and analyze the crack evolution law and temperature change law obtained in step 4 with the mapping relationship F in step 2 to determine the reliability of the suspected damaged part of the on-site sealing layer (2).

2. The method for identifying damage to the flexible sealing layer of a compressed air energy storage underground cavern according to claim 1, characterized in that: The cylindrical test piece (1) comprises a flexible sealing layer (11) rolled into a cylindrical shape, and steel cover plates (12) arranged at the upper and lower ends of the flexible sealing layer (11), wherein the upper end of the steel cover plate (12) is provided with a through hole for a steel pipe for charging and discharging gas (13) to pass through, an air pump (14) is arranged at one end of the steel pipe for charging and discharging gas (13) away from the steel cover plate (12), and a dehumidifier (15) is also arranged in the middle of the steel pipe for charging and discharging gas (13).

3. The method for identifying damage to the flexible sealing layer of a compressed air energy storage underground cavern according to claim 1, characterized in that: The wall thickness of the cylindrical test piece (1) is consistent with the thickness of the on-site sealing layer (2). When performing the inflation and deflation test, the inflation and deflation pressure is the same as the on-site inflation and deflation pressure value, which is 6-10Mpa.

4. The method for identifying damage to the flexible sealing layer of a compressed air energy storage underground cavern according to claim 1, characterized in that: When testing the sealing layer (2) on site in step 3 and step 4, first use a transparent glass cover (6) resistant to high temperature and high pressure to cover the three-dimensional laser scanning device (3), the infrared imaging device (4) and the temperature detector (5), and then put them into the site for testing, while ensuring that the three devices are electrically connected to the computer command system (7).

5. The method for identifying damage to the flexible sealing layer of a compressed air energy storage underground cavern according to claim 1, characterized in that: When it is determined in step 5 that the reliability of the suspected damaged part of the sealing layer is low, the computer command system (7) can control the high-pressure spraying system (8) to carry out rapid temporary repair of the suspected damaged part by high-pressure spraying of UHPC concrete and ECC concrete, and then replace it with the original flexible sealing layer material.

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