Salt cavern compressed air energy storage simulation test system and test method

Abstract

The invention relates to a salt cavern compressed air energy storage simulation test system and test method. The test system comprises a test model, a ground stress loading system, an air circulation charging and discharging system, a brine drainage system and a data monitoring and collecting system. The test model comprises a surrounding rock model and a salt cavern model, the surrounding rock model comprises a peripheral rock block and an internal salt block, the peripheral rock block is arranged on the outer side of the internal salt block, and the internal salt block is provided with a cavity; the salt cavern models are at least partially arranged on the two sides of the inner salt block in the axial direction, and the salt cavern models can seal the cavity and transmit the load borne by the inner salt block to the peripheral rock block; the ground stress loading can apply a load in a direction from a peripheral rock block to an internal salt block to the test model; the air circulation charging and discharging system is communicated with the cavity, the air circulation charging and discharging system can convey and monitor high-pressure gas, the brine drainage system is communicated with the cavity, and the brine drainage system can convey and monitor brine; the data monitoring and acquisition system comprises a monitoring instrument and a data acquisition instrument.

Description

Technical Field

[0001] The present application relates to the technical field of energy storage power stations, and in particular to a salt cavern compressed air energy storage simulation test system and test method. Background Art

[0002] Salt caverns are chambers formed after water-soluble mining of underground rock formations. They are high-quality underground space resources such as oil, natural gas, and compressed air. There are many salt cavern compressed air energy storage power stations under construction or already built in my country. my country has many interlayers in salt layers and thin salt layers, and a large amount of insoluble sediment is accumulated at the bottom of the salt caverns. When using the cavity, the traditional gas injection and brine removal method places the brine removal column above the sediment interface, resulting in the inability to discharge the brine below the sediment interface, and the available effective gas storage space is only the volume above the sediment. In order to expand the effective volume, a bottom gas injection and brine removal method has been proposed in recent years, which can discharge the brine inside the sediment and use the pore space inside the sediment to store gas. Sediment and brine are necessary products in the formation of salt caverns. Regardless of the utilization method, the compressed air energy storage process will involve brine and sediment. The study of the influence of both on the storage and operation performance of salt caverns is crucial, especially the daily cycle of compressed air energy storage, which will cause repeated changes in temperature and pressure inside the salt cavern. Brine and sediment will occupy the gas storage volume and affect temperature transfer, thereby affecting the long-term operation of salt caverns. However, there are few salt cavern compressed air energy storage power stations in operation now, and the impact of sediment and brine cannot be effectively evaluated. It is necessary to carry out relevant physical model tests for comparative research. Summary of the invention

[0003] A first aspect of an embodiment of the present application provides a salt cavern compressed air energy storage simulation test system, which can simulate the storage performance and surrounding rock temperature stress changes of a salt cavern during compressed air energy storage indoors, revealing the effects of brine and sediment on stored energy, surrounding rock temperature and strain, thereby evaluating the salt cavern energy storage performance under real conditions.

[0004] The salt cavern compressed air energy storage simulation test system provided in the first aspect of the embodiment of the present application includes:

[0005] A test model, wherein the test model comprises a surrounding rock model and a salt cave model, wherein the surrounding rock model comprises an outer rock block and an inner salt block, wherein the outer rock block is arranged outside the inner salt block, and the outer rock block and the inner salt block are in close contact to transfer the load, and the inner salt block has a cylindrical cavity, and the cavity extends along the axial direction of the inner salt block and penetrates the inner salt block; the salt cave model is at least partially arranged on both sides of the inner salt block along the axial direction, and the salt cave model can seal the cavity and transfer the load borne by the inner salt block to the outer rock block;

[0006] A ground stress loading system, wherein the ground stress loading system can apply a load from the peripheral rock block to the internal salt block to the test model;

[0007] An air circulation charging and discharging system and a brine pumping and discharging system, wherein the air circulation charging and discharging system is connected to the cavity, and the air circulation charging and discharging system is capable of conveying and monitoring high-pressure gas, and the brine pumping and discharging system is connected to the cavity, and the brine pumping and discharging system is capable of conveying and monitoring brine;

[0008] The data monitoring and acquisition system comprises a monitoring instrument and a data acquisition device. The monitoring instrument can perform data monitoring on the test model. The data acquisition device is data-connected to the monitoring instrument and can perform data transmission and processing.

[0009] In addition, the salt cavern compressed air energy storage simulation test system provided in the embodiment of the present application may also have the following additional technical features:

[0010] In an optional scheme, the salt cave model includes a sealing plug, a rigid connecting rod and a constraint disk, the sealing plug is respectively arranged on both sides of the cavity along the axial direction, and the sealing plug is sequentially provided with an insulation layer and a sealing layer on the side facing the cavity; the rigid connecting rod passes through the cavity and is connected to the sealing plug and the constraint disk on both sides, the constraint disk is located on the side of the sealing plug away from the cavity, and the constraint disk can directly or indirectly abut against the outer wall of the outer rock block.

[0011] In an optional scheme, the surrounding rock model also includes a fixed plate, a loading plate and a load-bearing base, the fixed plate is arranged on the opposite side of the peripheral rock block along a first direction, the first direction is the axial direction of the internal salt block, the load-bearing base is arranged at the bottom of the peripheral rock block, and the fixed plate is fixedly connected to the load-bearing base; there are multiple loading plates, and the multiple loading plates are respectively arranged on the top of the peripheral rock block and the outer wall of the peripheral rock block adjacent to the fixed plate on one side, and the loading plate is directly or indirectly connected to the ground stress loading system and bears the load.

[0012] In an optional scheme, the fixing plate is provided with a through hole at a position corresponding to the cavity, the sealing plug part passes through the through hole and seals the cavity, a sealing ring is provided between the sealing plug and the hole wall of the through hole, the restraint plate is located on the outside of the fixing plate and can abut against the fixing plate; a triangular fixing seat is provided between the load-bearing base and the fixing plate.

[0013] In an optional scheme, the ground stress loading system includes a hydraulic head, a loading frame, a hydraulic power system and a computer; the hydraulic head is connected to the hydraulic power system and the computer through a line pipeline, one end of the hydraulic head abuts against the loading frame, and the other end abuts against the loading plate to apply load to the loading plate.

[0014] In an optional solution, the monitoring instrument includes an intracavity pressure monitor, an intracavity temperature monitor, a cavity wall temperature monitor, a sediment temperature monitor, a surrounding rock strain monitor and a surrounding rock temperature detector;

[0015] The intracavity pressure monitor and the intracavity temperature monitor are arranged at the axial position of the cavity, the number of the cavity wall temperature monitors is multiple, and the multiple cavity wall temperature monitors are arranged at intervals on the inner wall of the cavity, the sediment temperature monitor is arranged in the cavity and is used to monitor the temperature of the sediment and saturated brine; the number of the surrounding rock strain monitors and the surrounding rock temperature detectors is multiple, and the multiple surrounding rock strain monitors and the surrounding rock temperature detectors are arranged in the internal salt block in the form of 6 groups in a 60° circular direction.

[0016] In an optional scheme, the air circulation and charging and discharging system includes an air inlet pipeline and an air outlet pipeline, the air inlet pipeline connects the cavity and the high-pressure gas source, and the air outlet pipeline connects the cavity and the air purifier; the air inlet pipeline is provided with a compressor, a heat exchanger, a first valve, a first flow meter and a pressure gauge, and the air outlet pipeline is provided with a second valve and a second flow meter.

[0017] In an optional scheme, the brine extraction system includes a brine delivery pipe, a third valve and a liquid storage container, the brine delivery pipe connects the cavity and the liquid storage container, the third valve is arranged on the brine delivery pipe, and a filter is arranged in the pipe mouth of the brine delivery pipe.

[0018] A second aspect of the present application provides a salt cavern compressed air energy storage simulation test method, wherein the salt cavern compressed air energy storage simulation test method uses the salt cavern compressed air energy storage simulation test system in the first aspect of the embodiment to perform a simulation test, and the salt cavern compressed air energy storage simulation test method comprises the following steps:

[0019] The test model is fabricated and assembled to form a cavity of known size, a known volume of sediment is laid in the cavity to a preset height, and the salt cavern model is adjusted to seal the cavity and form a closed space;

[0020] Open the valve of the brine extraction system, inject brine to a preset height in the cavity, close the valve, record the volume of the brine flowing in, and then calculate the gas storage volume by the original volume of the cavity, the sediment volume and the brine volume;

[0021] Open the air intake valve of the air circulation charging and discharging system, inject compressed air into the cavity, record the gas injection flow and pressure, and when the pressure in the cavity reaches a preset value, close the valve, record the total amount of gas injected and the temperature and pressure values ​​inside the cavity, and record the surrounding rock heat transfer process. This process may or may not apply ground stress. When applying ground stress, add data monitoring of surrounding rock strain;

[0022] The gas in the cavity is slowly released, during which the temperature and pressure data in the cavity are monitored, and the pressure and flow data of the released gas as well as the strain and temperature data of the surrounding rock are recorded.

[0023] In an optional solution, when making the test model, at least three test models with the same material and cavity size are prepared and the test is carried out in sequence;

[0024] When conducting a test on one test model, the amount of sediment added is half of the volume of the cavity and no brine is added; when conducting a test on another test model, the amount of sediment added is half of the volume of the cavity and brine is added; when conducting a test on the second test model, the amount of sediment and brine added is half of that of the second test model;

[0025] The monitoring data of at least three of the test models are compared and analyzed to evaluate the effects of brine and sediment on the compressed air storage performance and surrounding rock stability, as well as the advantages and disadvantages of different gas storage modes of gas injection.

[0026] The beneficial effects of the embodiments of the present application are:

[0027] The salt cavern compressed air energy storage simulation test system and experimental method can use the on-site salt core and interlayer as the test model, obtain the heat transfer parameters and mechanical parameters of the salt layer, brine and sediment according to the monitoring data, and provide basic data support for the engineering site. During the experiment, the surrounding rock stress data under the same internal pressure and different temperatures can be used to reflect the influence of temperature on the mechanical properties of the salt cavity, evaluate the temperature effect and whether to take relevant measures; it can also carry out the simulation of the gas injection and brine discharge process to provide a reference for the optimal rate of gas injection and brine discharge, or conduct short-term and long-term cycle charging and discharging tests to provide a basis for the stability of the salt cavern under short-term and long-term cycle injection and production; it can also carry out comparative tests under various sediment and brine volumes to evaluate the influence of brine and sediment on compressed air storage performance and surrounding rock stability, and provide support for the optimal solution for actual engineering. It can reveal the coupling mechanism of the four major media of surrounding rock, sediment, brine and compressed air under the action of temperature and pressure, and more realistically reflect the operating mechanism and process of compressed air storage in salt caverns. The stress of the test system is approximately a plane strain model, which is different from the three-dimensional stress of the real salt cavern. However, the plane strain system is simple and easy to understand, easy to operate and implement, and also convenient for comparing the test results with the theoretical model.

[0028] It should be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic diagram of the composition and structure of the salt cavern compressed air energy storage simulation test system provided in this application;

[0030] Figure 2 A schematic diagram of the structure of a test model provided in this application in a specific embodiment;

[0031] Figure 3 A schematic diagram of the structure of a salt cavern model provided in the present application in a specific embodiment;

[0032] Figure 4 A schematic structural diagram of a sealing plug provided in the present application in a specific embodiment;

[0033] Figure 5 Schematic diagram of the composition and installation location of the monitoring instrument provided for this application.

[0034] Reference numerals: outer rock block 11, inner salt block 12, cavity 13, sediment 131, saturated brine 132, sealing layer 133, gas transmission pipe column 134, brine transmission pipe column 135, load-bearing base 14, fixing plate 15, triangular fixing seat 16, sealing plug 17, insulation layer 171, sealing ring 172, restraining plate 18, rigid connecting rod 19, bolt 191, hydraulic head 21, loading plate 22, loading frame 23, hydraulic power system 24, electric Brain 25, compressor 31, heat exchanger 32, air inlet pipeline 33, first valve 34, first flowmeter 35, pressure gauge 36, air outlet pipeline 37, purifier 38, brine pipe 41, third valve 42, liquid storage container 43, intracavity pressure monitor 511, intracavity temperature monitor 512, cavity wall temperature monitor 513, sediment temperature monitor 514, surrounding rock strain monitor 515, surrounding rock temperature detector 516, data acquisition instrument 52.

[0035] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application. DETAILED DESCRIPTION

[0036] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0037] It should be clear that the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0038] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0039] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0040] It should be noted that the directional words such as "upper", "lower", "left", and "right" described in the embodiments of the present application are described at the angles shown in the accompanying drawings and should not be understood as limiting the embodiments of the present application. In addition, in the context, it is also necessary to understand that when it is mentioned that an element is connected to another element "upper" or "lower", it can not only be directly connected to another element "upper" or "lower", but also indirectly connected to another element "upper" or "lower" through an intermediate element.

[0041] like Figure 1-5As shown, the first aspect of the embodiment of the present application provides a salt cavern compressed air energy storage simulation test system, which includes a test model, a ground stress loading system, an air circulation charging and discharging system, a brine extraction system and a data monitoring and acquisition system. Among them, the test model includes a surrounding rock model and a salt cavern model, and the surrounding rock model includes an outer rock block 11 and an inner salt block 12. The outer rock block 11 is arranged on the outside of the inner salt block 12, and the outer rock block 11 and the inner salt block 12 are in close contact to transfer the load. The inner salt block 12 has a cylindrical cavity 13, and the cavity 13 extends along the axial direction of the inner salt block 12 and penetrates the inner salt block 12; the salt cavern model is at least partially arranged on both sides of the inner salt block 12 along the axial direction, and the salt cavern model can seal the cavity 13 and transfer the load borne by the inner salt block 12 to the outer Surrounding rock block 11; ground stress loading can apply load from the outer rock block 11 to the internal salt block 12 to the test model; the air circulation charging and discharging system is connected with the cavity 13, and the air circulation charging and discharging system can transport and monitor high-pressure gas; the brine extraction system is connected with the cavity 13, and the brine extraction system can transport and monitor brine; the data monitoring and acquisition system includes a monitoring instrument and a data acquisition instrument 52, the monitoring instrument can monitor the data of the test model, and the data acquisition instrument 52 is connected with the monitoring instrument data and can transmit and process data.

[0042] In this embodiment, the surrounding rock model is composed of a peripheral rock block 11 and an internal salt block 12. The peripheral rock block 11 is in close contact with the internal salt block 12, so as not to affect the transfer of load. A circular hole is reserved in the middle of the peripheral rock block 11. The cross-section of the peripheral rock block 11 is a square, and the thickness is less than the side length of the cross-section square. The circular hole of the peripheral rock block 11 is filled with a ring-shaped internal salt block 12. The internal salt block 12 has a cylindrical cavity 13, and the thickness of the internal salt block 12 is consistent with that of the peripheral rock block 11.

[0043] The test model has a rectangular outer contour, with a size of 1m×1m×0.5m (thickness), and the outer rock blocks are common rocks, such as sandstone, marble, granite, etc. The inner salt block 12 is salt rock, which is pressed with salt powder or Himalayan salt blocks, with an outer contour of a cylinder, with a size of 0.5m×0.5m, and a conductive salt cavity with a diameter of 0.2m is reserved in the middle of the salt block. The rock block is in close contact with the salt block, which does not affect the transfer of load.

[0044] like Figure 2-4As shown, in a specific embodiment, the salt cave model includes a sealing plug, a rigid connecting rod 19 and a restraining disk 18, the sealing plug is respectively arranged on both sides of the cavity 13 along the axial direction, and the side of the sealing plug facing the cavity 13 is sequentially provided with an insulation layer 171 and a sealing layer 133, and the sealing layer 133 is made of rubber or glass fiber reinforced plastics. The rigid connecting rod 19 passes through the cavity 13 and is connected to the sealing plugs and the restraining disk 18 on both sides, the restraining disk 18 is located on the side of the sealing plug away from the cavity 13, and the restraining disk 18 can directly or indirectly abut against the outer wall of the peripheral rock block 11.

[0045] like Figure 2 As shown, in a specific embodiment, the surrounding rock model also includes a fixed plate 15, a loading plate 22 and a load-bearing base 14, the fixed plate 15 is arranged on the opposite side of the peripheral rock block 11 along the first direction, the first direction is the axial direction of the internal salt block 12, the load-bearing base 14 is arranged at the bottom of the peripheral rock block 11, and the fixed plate 15 is fixedly connected to the load-bearing base 14; there are multiple loading plates 22, and the multiple loading plates 22 are respectively arranged on the top of the peripheral rock block 11 and the outer wall of the peripheral rock block 11 adjacent to the fixed plate 15, and the loading plate 22 is directly or indirectly connected to the ground stress loading system and bears the load.

[0046] like Figure 3 and Figure 4 As shown, in a specific embodiment, a through hole is opened in the fixed plate 15 at a position corresponding to the cavity 13, the sealing plug passes through the through hole and seals the cavity 13, a sealing ring 172 is arranged between the sealing plug and the hole wall of the through hole, the restraint plate 18 is located on the outside of the fixed plate 15 and can abut against the fixed plate 15; a triangular fixing seat 16 is arranged between the load-bearing base 14 and the fixed plate 15.

[0047] Specifically, Figure 2As shown, the bottom of the test model is a load-bearing base 14, the top and two opposite sides are provided with loading plates 22, and the front and rear sides are provided with fixed plates 15, wherein the fixed plate 15 is installed in a recessed manner with the base, and triangular fixed seats 16 are provided on both sides. The salt cave model is based on the cavity 13 of the internal salt block 12, and sealing plugs are set at both ends of the chamber. The sealing plug has an insulation layer 171 and a sealing layer 133 on one side of the chamber interior, which is used to ensure that the temperature of the salt chamber is not transmitted from both ends and to ensure the sealing of both ends. A circular hole with a sealing plug 17 section is reserved in the middle of the fixed plate 15, and a sealing ring 172 is provided on the reserved hole wall. The outer side of the sealing plug is a restraining disk 18, the size of the restraining disk 18 is larger than the reserved circular hole of the fixed plate 15, and a rigid connecting rod 19 is passed through the center of the cavity and locked with a bolt 191, so that the restraining disk 18, the fixed plate 15, the sealing plug and the sample model form a sealed whole. In this way, the two ends are fixed, and the sealing plugs at both ends of the test model will not be pushed out by the pressure under the action of internal pressure, which ensures the sealing of the salt cavity for storing high-pressure gas, and also enables the surrounding rocks to bear the load, restoring the plane strain stress state, and ensuring the reliability of the test results.

[0048] like Figure 1 As shown, in a specific embodiment, the ground stress loading system includes a hydraulic head 21, a loading frame 23, a hydraulic power system 24 and a computer 25; the hydraulic head 21 is connected to the hydraulic power system 24 and the computer 25 through a line pipeline, one end of the hydraulic head 21 abuts against the loading frame 23, and the other end abuts against the loading plate 22 to apply a load to the loading plate 22. The ground stress loading system can achieve a maximum pressure loading of 10MPa, and the top and the left and right sides can achieve loading of different pressure values, reflecting different side pressure coefficients. The loading system has a displacement protection device to prevent uncontrolled damage caused by large deformation.

[0049] like Figure 5 As shown, in a specific embodiment, the monitoring instrument includes an intracavity pressure monitor 511, an intracavity temperature monitor 512, a cavity wall temperature monitor 513, a sediment temperature monitor 514, a surrounding rock strain monitor 515 and a surrounding rock temperature detector 516; the intracavity pressure monitor 511 and the intracavity temperature monitor 512 are arranged at the axial position of the cavity 13, the number of cavity wall temperature monitors 513 is multiple, and the multiple cavity wall temperature monitors 513 are arranged at intervals on the inner wall of the cavity 13, and the sediment temperature monitor 514 is arranged in the cavity 13 and is used to monitor the temperature of the sediment 131 and the saturated brine 132; the number of surrounding rock strain monitors 515 and surrounding rock temperature detectors 516 is multiple, and the multiple surrounding rock strain monitors 515 and surrounding rock temperature detectors 516 are arranged in the internal salt block 12 in a 60° circumferential manner. The monitoring depth reaches the contact seam of the two salt rocks, and the peripheral salt layer is not monitored. The monitoring instrument is connected to the data acquisition instrument 52 and is also connected to the aforementioned computer 25 .

[0050] like Figure 1 As shown, in a specific embodiment, the air circulation charging and discharging system includes an air inlet pipeline 33 and an air outlet pipeline 37, the air inlet pipeline 33 connects the cavity 13 and the high-pressure gas source, and the air outlet pipeline 37 connects the cavity 13 and the air purifier 38; the air inlet pipeline 33 is provided with a compressor 31, a heat exchanger 32, a first valve 34, a first flowmeter 35 and a pressure gauge 36, and the air outlet pipeline 37 is provided with a second valve and a second flowmeter. The brine extraction system includes a brine delivery pipe 41, a third valve 42 and a liquid storage container 43, the brine delivery pipe 41 connects the cavity 13 and the liquid storage container 43, the third valve 42 is provided on the brine delivery pipe 41, and a filter is provided in the pipe mouth of the brine delivery pipe 41.

[0051] In order to maintain the filling and discharge of gas and the increase and decrease of brine, a gas transmission pipe column 134 and a brine transmission pipe column 135 are reserved at one axial end of the internal salt block 12, and are connected to the outside through the sealing plug and the constraint disk 18. The gas transmission pipe column 134 is connected to the air circulation charging and discharge system, and the brine transmission pipe column 135 is connected to the brine extraction system. In addition, the rigid connecting rod 19, the contact between the pipe column and the sealing plug are sealed, so that the cavity 13 forms a sealed salt cavity, and the bottom is filled with sediment 131 and saturated brine 132. The sediment 131 is obtained by soaking and crushing the interlayer on site, and the saturated brine 132 is obtained by dissolving the salt layer sampled on site, or the brine is prepared in the laboratory to reach saturation to ensure that the internal salt block 12 will no longer be dissolved. The original volume of the cavity 13 and the volume of the sediment 131 can be known, and the gas storage volume of the salt cavity can be obtained from the volume of the brine. These volume data serve as basic parameters for subsequent experimental research.

[0052] In this embodiment, the high-pressure gas source provides compressed air of a certain temperature and pressure through the compressor 31 and the heat exchanger 32. The air inlet pipeline 33 is connected to one end of the high-pressure gas source. After the compressed gas is formed, it is connected to the cavity 13 of the internal salt block 12 through the pipeline, and the gas is injected into the cavity 13. The air inlet pipeline 33 is provided with a first valve 34 for flow control, and a first flow meter and a pressure gauge 36 are provided to monitor and record the gas flow rate and pressure. The connection end of the air outlet pipeline 37 and the purifier 38 is an air outlet pipeline. The compressed gas in the cavity 13 passes through the air outlet pipeline 37 and is released after desalination treatment by the purifier 38. The air outlet pipeline is provided with a second valve and a second flow meter. The air circulation charging and discharging system obtains a gas source of a certain pressure and temperature from the compressor 31 through the heat exchanger 32, and inputs it into the cavity 13 of the internal salt block 12. The internal salt block 12 and the salt cave model can ensure the sealing within 8MPa pressure.

[0053] The brine delivery pipe 41 for brine extraction connects the liquid storage container 43 and the cavity 13, and a third valve 42 is provided in the middle for opening and closing control. The pipe column mouth (brine delivery pipe 41) in the cavity 13 is lowered to the bottom, and a filter is provided at the pipe mouth to prevent the sediment 131 from blocking the pipe column. The liquid storage container 43 has a precise scale, which can accurately obtain the volume data of the brine. The brine is injected through the height difference between the liquid storage container 43 and the salt cavern, and discharged by the pressure of compressed air.

[0054] A second aspect of the present application provides a salt cavern compressed air energy storage simulation test method, which uses the salt cavern compressed air energy storage simulation test system in the first aspect of the embodiment to perform a simulation test, and the simulation test method includes the following steps:

[0055] The test model is fabricated and assembled to form a cavity 13 of known size, a sediment 131 of known volume is laid in the cavity 13 to a preset height, and the salt cave model is adjusted to seal the cavity 13 and form a closed space;

[0056] Open the valve of the brine extraction system, inject brine to a preset height in the cavity 13, close the valve, record the volume of the brine flowing in, and then calculate the gas storage volume by the original volume of the cavity 13, the volume of the sediment 131 and the volume of the brine;

[0057] Open the air intake valve of the air circulation charging and discharging system, inject compressed air into the cavity 13, record the gas injection flow and pressure, and when the pressure in the cavity 13 reaches the preset value, close the valve, record the total amount of gas injected and the temperature and pressure values ​​inside the cavity 13, and record the surrounding rock heat transfer process. This process may or may not apply ground stress. When applying ground stress, add data monitoring of surrounding rock strain;

[0058] The gas in the cavity 13 is slowly released, during which the temperature and pressure data in the cavity 13 are monitored, and the pressure and flow data of the released gas as well as the strain and temperature data of the surrounding rock are recorded.

[0059] The test system can be used to conduct a comparative test of compressed air energy storage under different sediment 131 brine schemes. By comparing the temperature, pressure and stress data under different schemes, the effects of brine and sediment 131 on compressed air storage performance and surrounding rock stability can be evaluated.

[0060] In a specific embodiment, when making the test model, at least three test models with the same material and cavity 13 size are prepared and the test is carried out in sequence;

[0061] When testing one test model, the sediment 131 added is half the volume of the cavity 13 and no brine is added; when testing another test model, the sediment 131 added is half the volume of the cavity 13 and brine is added; when testing the second test model, the amount of sediment 131 and brine added is half of that of the second test model;

[0062] The monitoring data of at least three test models were compared and analyzed to evaluate the effects of brine and sediment 131 on the compressed air storage performance and surrounding rock stability, as well as the advantages and disadvantages of different gas storage modes of gas injection.

[0063] Specifically, taking three test models (Sample 1-Sample 3) as an example, Sample 1 carried out a test with half the volume of the cavity containing sediment 131 but no brine, Sample 2 carried out a test with the same amount of sediment 131 as Sample 1 and with brine, and Sample 3 carried out a test with only half the volume of the cavity containing sediment 131 and brine.

[0064] Before testing Sample 1, a predetermined amount of sediment 131 is laid in the salt cavity, and after the test model and other systems are installed, saturated brine 132 is injected into the salt cavity through the brine pipe 41 until the salt cavity is full. At this time, the air circulation charging and discharging system is started, and compressed air with a certain flow, pressure and temperature is injected into the salt cavity through the gas injection pipe. The high-pressure gas will press the brine out from the bottom. When all the brine is discharged (simulating the use of sediment gas storage mode), close the brine pipe valve, continue to inject gas, make the cavity reach the preset pressure, and close the gas injection pipe valve. Record the amount of gas injected (kg) during this process, and the cavity, cavity wall, and brine temperature monitoring data. And keep the brine pipe valve closed in the future, carry out multiple cycles of compressed air charging and discharging tests, and record the pressure, temperature and strain data.

[0065] When carrying out the test of Sample 2, when the brine just stays above the sediment 131 during the gas injection and brine removal stage (simulating the traditional gas injection and brine removal method), the pipe column valve is closed, and the compressed air injection and production process at the same rate is carried out, and the monitoring data is recorded during the period. Sample 3 basically completely repeats the operation process of Sample 2, but pays attention to the difference in the location of brine discharge. The monitoring data under the three schemes are compared and analyzed to evaluate the effects of brine and sediment 131 on the compressed air storage performance and surrounding rock stability, as well as the advantages and disadvantages of different gas storage modes of gas injection, and put forward engineering construction suggestions.

[0066] The system can also conduct comparative tests of different operating parameters, such as comparative tests of the impact of different gas injection rates. Under different schemes, the conditions such as brine and sediment 131 in the salt cavity remain consistent, and only the rate of compressed air injection into the salt cavity is changed. When the salt cavity reaches the same pressure during gas injection, the cavity temperature, cavity wall temperature, sediment 131 temperature, and surrounding rock temperature and deformation are recorded, and the total injected gas mass is recorded to evaluate the impact of the gas injection rate on gas storage performance and coupling process.

[0067] It can be seen from the above embodiments that the salt cave compressed air energy storage simulation test system and experimental method in the embodiments of the present application can use the on-site salt core and interlayer as the test model, obtain the heat transfer parameters and mechanical parameters of the salt layer, brine and sediment 131 according to the monitoring data, and provide basic data support for the engineering site. During the experiment, the surrounding rock stress data under the same internal pressure and different temperatures can be used to reflect the influence of temperature on the mechanical properties of the salt cavity, evaluate the temperature effect and whether to take relevant measures; it can also carry out the simulation of the gas injection and brine removal process to provide a reference for the optimal rate of gas injection and brine removal, or conduct short-term and long-term cycle charging and discharging tests to provide a basis for the stability of the salt cave under short-term and long-term cycle injection and production; it can also carry out comparative tests under various sediments 131 and brine volumes to evaluate the influence of brine and sediment 131 on the compressed air storage performance and surrounding rock stability, and provide support for the optimal solution for actual engineering. It can reveal the coupling mechanism of the four medium bodies of surrounding rock, sediment 131, brine and compressed air under the action of temperature and pressure, and more realistically reflect the operating mechanism and process of salt cavern storage of compressed air. The stress of the test system is approximately a plane strain model, which is different from the three-dimensional stress of the real salt cavern. However, the plane strain system is simple and easy to understand, easy to operate and implement, and also convenient for comparing the test results with the theoretical model.

[0068] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A salt cavern compressed air energy storage simulation test system, characterized in that: include: A test model, wherein the test model comprises a surrounding rock model and a salt cave model, wherein the surrounding rock model comprises an outer rock block and an inner salt block, wherein the outer rock block is arranged outside the inner salt block, and the outer rock block and the inner salt block are in close contact to transfer the load, and the inner salt block has a cylindrical cavity, and the cavity extends along the axial direction of the inner salt block and penetrates the inner salt block; the salt cave model is at least partially arranged on both sides of the inner salt block along the axial direction, and the salt cave model can seal the cavity and transfer the load borne by the inner salt block to the outer rock block; A ground stress loading system, wherein the ground stress loading system can apply a load from the peripheral rock block to the internal salt block to the test model; An air circulation charging and discharging system and a brine pumping and discharging system, wherein the air circulation charging and discharging system is connected to the cavity, and the air circulation charging and discharging system is capable of conveying and monitoring high-pressure gas, and the brine pumping and discharging system is connected to the cavity, and the brine pumping and discharging system is capable of conveying and monitoring brine; The data monitoring and acquisition system comprises a monitoring instrument and a data acquisition device. The monitoring instrument can perform data monitoring on the test model. The data acquisition device is connected to the monitoring instrument and can transmit and process data.

2. The salt cavern compressed air energy storage simulation test system according to claim 1 is characterized in that: The salt cave model comprises a sealing plug, a rigid connecting rod and a restraining disk, wherein the sealing plug is respectively arranged on both sides of the cavity along the axial direction, and a thermal insulation layer and a sealing layer are sequentially arranged on the side of the sealing plug facing the cavity; the rigid connecting rod passes through the cavity and is connected to the sealing plug and the restraining disk on both sides, the restraining disk is located on the side of the sealing plug away from the cavity, and the restraining disk can directly or indirectly abut against the outer wall of the peripheral rock block.

3. The salt cavern compressed air energy storage simulation test system according to claim 2 is characterized in that: The surrounding rock model also includes a fixed plate, a loading plate and a load-bearing base. The fixed plate is arranged on the opposite side of the peripheral rock block along the first direction, and the first direction is the axial direction of the internal salt block. The load-bearing base is arranged at the bottom of the peripheral rock block, and the fixed plate is fixedly connected to the load-bearing base. There are multiple loading plates, and the multiple loading plates are respectively arranged on the top of the peripheral rock block and the outer wall of the peripheral rock block adjacent to the fixed plate. The loading plate is directly or indirectly connected to the ground stress loading system and bears the load.

4. The salt cavern compressed air energy storage simulation test system according to claim 3 is characterized in that: The fixing plate is provided with a through hole at a position corresponding to the cavity, the sealing plug part passes through the through hole and seals the cavity, a sealing ring is provided between the sealing plug and the hole wall of the through hole, the restraining disk is located on the outer side of the fixing plate and can abut against the fixing plate; a triangular fixing seat is provided between the load-bearing base and the fixing plate.

5. The salt cavern compressed air energy storage simulation test system according to claim 3 or 4, characterized in that: The ground stress loading system includes a hydraulic head, a loading frame, a hydraulic power system and a computer; the hydraulic head is connected to the hydraulic power system and the computer through line pipelines, one end of the hydraulic head abuts against the loading frame, and the other end abuts against the loading plate to apply load to the loading plate.

6. The salt cavern compressed air energy storage simulation test system according to any one of claims 1 to 4, characterized in that: The monitoring instruments include an intracavity pressure monitor, an intracavity temperature monitor, a cavity wall temperature monitor, a sediment temperature monitor, a surrounding rock strain monitor and a surrounding rock temperature detector; The intracavity pressure monitor and the intracavity temperature monitor are arranged at the axial position of the cavity, the number of the cavity wall temperature monitors is multiple, and the multiple cavity wall temperature monitors are arranged at intervals on the inner wall of the cavity, the sediment temperature monitor is arranged in the cavity and is used to monitor the temperature of the sediment and saturated brine; the number of the surrounding rock strain monitors and the surrounding rock temperature detectors is multiple, and the multiple surrounding rock strain monitors and the surrounding rock temperature detectors are arranged in the internal salt block in the form of 6 groups in a 60° circular direction.

7. The salt cavern compressed air energy storage simulation test system according to claim 6 is characterized in that: The air circulation and charging and discharging system includes an air inlet pipeline and an air outlet pipeline, the air inlet pipeline connects the cavity and the high-pressure gas source, and the air outlet pipeline connects the cavity and the air purifier; the air inlet pipeline is provided with a compressor, a heat exchanger, a first valve, a first flow meter and a pressure gauge, and the air outlet pipeline is provided with a second valve and a second flow meter.

8. The salt cavern compressed air energy storage simulation test system according to any one of claims 1-4 or 7, characterized in that: The brine extraction system includes a brine delivery pipe, a third valve and a liquid storage container. The brine delivery pipe connects the cavity and the liquid storage container. The third valve is arranged on the brine delivery pipe. A filter is arranged in the pipe mouth of the brine delivery pipe.

9. A salt cavern compressed air energy storage simulation test method, characterized in that: The salt cavern compressed air energy storage simulation test method uses the salt cavern compressed air energy storage simulation test system described in any one of claims 1 to 8 to perform a simulation test, and the salt cavern compressed air energy storage simulation test method comprises the following steps: The test model is fabricated and assembled to form a cavity of known size, a known volume of sediment is laid in the cavity to a preset height, and the salt cavern model is adjusted to seal the cavity and form a closed space; Open the valve of the brine extraction system, inject brine to a preset height in the cavity, close the valve, record the volume of the brine flowing in, and then calculate the gas storage volume by the original volume of the cavity, the sediment volume and the brine volume; Open the air intake valve of the air circulation charging and discharging system, inject compressed air into the cavity, record the gas injection flow and pressure, and when the pressure in the cavity reaches a preset value, close the valve, record the total amount of gas injected and the temperature and pressure values ​​inside the cavity, and record the surrounding rock heat transfer process. This process may or may not apply ground stress. When applying ground stress, add data monitoring of surrounding rock strain; The gas in the cavity is slowly released, during which the temperature and pressure data in the cavity are monitored, and the pressure and flow data of the released gas as well as the strain and temperature data of the surrounding rock are recorded.

10. The salt cavern compressed air energy storage simulation test method according to claim 9, characterized in that: When making the test model, at least three test models with the same material and cavity size are prepared and the test is carried out in sequence; When conducting a test on one test model, the sediment added is half of the volume of the cavity and no brine is added; when conducting a test on another test model, the sediment added is half of the volume of the cavity and brine is added; when conducting a test on the second test model, the amount of sediment and brine added is half of that of the second test model; The monitoring data of at least three of the test models are compared and analyzed to evaluate the effects of brine and sediment on the compressed air storage performance and surrounding rock stability, as well as the advantages and disadvantages of different gas storage modes of gas injection.

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