A salt cavern compressed air energy storage simulation test system and test method

Abstract

The present application relates to a salt cavern compressed air energy storage simulation test system and test method, the test system including a test model, a ground stress loading system, an air circulation charging and discharging system, a brine pumping and discharging system, and a data monitoring and acquisition system. The test model includes a surrounding rock model and a salt cavern model, the surrounding rock model including an outer rock block and an inner salt block, the outer rock block being arranged outside the inner salt block, and the inner salt block having a cavity; the salt cavern model is at least partially arranged on both sides of the inner salt block along the axial direction, the salt cavern model can seal the cavity and transfer the load borne by the inner salt block to the surrounding rock block; the ground stress loading can apply a load from the outer rock block to the inner salt block to the test model; the air circulation charging and discharging system is connected to the cavity and can transport and monitor high-pressure gas; the brine pumping and discharging system is connected to the cavity and can transport and monitor brine; the data monitoring and acquisition system includes 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 by solution mining in underground rock formations. They are valuable underground storage resources for oil, natural gas, and compressed air. When utilizing these chambers, traditional gas injection and brine removal methods place the brine removal tubing above the sediment interface, preventing the brine below the sediment interface from being drained. The available gas storage space is limited to the volume above the sediment. To expand this effective volume, bottom gas injection and brine removal have been proposed in recent years. This method removes the brine from the sediment, allowing the pore space within the sediment to be used for gas storage. Sediment and brine are essential byproducts of salt cavern formation. Regardless of the utilization method, compressed air energy storage involves both brine and sediment, and their impact on salt cavern storage and operational performance is crucial to study. In particular, the daily charge and discharge cycles of compressed air energy storage cause repeated fluctuations in temperature and pressure within the salt cavern. Brine and sediment occupy gas storage volume and affect temperature transfer, thus impacting the long-term operation of the salt cavern. However, there are currently few operational salt cave compressed air energy storage plants, making the impact of sediment and brine difficult to effectively assess. Physical model experiments are needed for comparative studies. Summary of the Invention

[0003] In a first aspect, 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 influence of brine and sediment on stored energy, surrounding rock temperature and strain, and thus 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, the test model comprising a surrounding rock model and a salt cave model, the surrounding rock model comprising an outer rock block and an inner salt block, the outer rock block being disposed outside the inner salt block and in close contact with the inner salt block for load transfer, the inner salt block having a cylindrical cavity extending axially along and penetrating the inner salt block; the salt cave model being at least partially disposed on both sides of the inner salt block along the axial direction, the salt cave model being capable of sealing the cavity and transferring 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 is capable of applying a load from the outer rock blocks to the inner salt blocks 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 in communication with the cavity and is capable of conveying and monitoring high-pressure gas, and the brine pumping and discharging system is in communication with the cavity and is capable of conveying and monitoring brine;

[0008] The data monitoring and acquisition system includes a monitoring instrument and a data acquisition device. The monitoring instrument can monitor the data of the test model. The data acquisition device is connected to the monitoring instrument and can transmit and process data.

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

[0010] In an optional solution, the salt cave model includes a sealing plug, a rigid connecting rod and a restraining disk. The sealing plug is respectively arranged on both sides of the cavity along the axial direction, and the side of the sealing plug facing the cavity is sequentially provided with an insulation layer and a sealing layer; 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.

[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 the 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. The loading plates are directly or indirectly connected to the ground stress loading system and bear the load.

[0012] In an optional solution, the fixing plate is provided with a through hole at a position corresponding to the cavity, the sealing plug portion 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 disk 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 solution, 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 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;

[0015] The intracavity pressure monitor and the intracavity temperature monitor are arranged at the axial center 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 monitor and the surrounding rock temperature detector is multiple, and the multiple surrounding rock strain monitors and the surrounding rock temperature detectors are arranged in the internal salt block in a 60° circular manner in 6 groups.

[0016] In an optional solution, the air circulation 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 solution, the brine extraction system includes a brine pipe, a third valve and a liquid storage container. The brine pipe connects the cavity and the liquid storage container. The third valve is arranged on the brine pipe. A filter is arranged in the pipe mouth of the brine 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 of the first aspect of the embodiment to perform a simulation test, and the salt cavern compressed air energy storage simulation test method includes the following steps:

[0019] The test model is fabricated and assembled to form a cavity of known size, sediment of known volume is laid in the cavity to a predetermined 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 brine flowing in, and then calculate the gas storage volume based on the original volume of the cavity, the volume of sediment, and the volume of brine;

[0021] Open the air inlet valve of the air circulation charging and discharging system, inject compressed air into the cavity, record the gas injection flow rate 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 can be done with or without applying ground stress. When applying ground stress, data monitoring of surrounding rock strain is added;

[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 tested 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 third 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 compressed air storage performance and surrounding rock stability, as well as the advantages and disadvantages of different gas injection storage modes.

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

[0027] This salt cavern compressed air energy storage simulation test system and experimental method can use on-site salt cores and interlayers as test models. Based on monitoring data, the heat transfer and mechanical parameters of the salt layer, brine, and sediment can be obtained, providing 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 impact of temperature on the mechanical properties of the salt cavern, evaluate the temperature effect, and determine whether relevant measures should be taken. Simulations of the gas injection and brine removal process can also be conducted to provide a reference for the optimal gas injection and brine removal rate. Short-term and long-term cyclic charge and discharge tests can also be conducted to provide a basis for the stability of the salt cavern under short-term and long-term cyclic injection and production. Comparative tests under various sediment and brine volumes can also be conducted to evaluate the impact of brine and sediment on compressed air storage performance and surrounding rock stability, providing support for the optimal solution for actual engineering projects. This system can reveal the coupling mechanism of the four major media—surrounding rock, sediment, brine, and compressed air—under the influence of temperature and pressure, more realistically reflecting the operating mechanism and process of compressed air storage in salt caverns. The stress on the test system is approximately a plane strain model, which is different from the three-dimensional stress in a real salt cavern. However, this plane strain system is simple to understand, easy to operate and implement, and also facilitates the comparison of test results with theoretical models.

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

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

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

[0031] Figure 3 A schematic structural diagram of a salt cavern model provided in this application in a specific embodiment;

[0032] Figure 4 A schematic structural diagram of a sealing plug provided in this 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 device 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 embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0038] The terms used in the embodiments of the present application are for the purpose of describing specific embodiments only and are not intended to limit the present application. The singular forms "a", "an", "the" 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 otherwise.

[0039] It should be understood that the term "and / or" as used herein is merely a description of the relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " in this document generally indicates that the associated objects 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 based on 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 should be understood that when it is mentioned that an element is connected to another element "on" or "under", it can not only be directly connected to the other element "on" or "under", but also be indirectly connected to the other element "on" or "under" through an intermediate element.

[0041] like Figure 1-5 As 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 pumping 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 passes through 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. 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 a 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 to the cavity 13, and the air circulation charging and discharging system can transport and monitor high-pressure gas, and the brine pumping system is connected to the cavity 13, and the brine pumping system can transport and monitor brine; the data monitoring and acquisition system includes a monitoring instrument and a data acquisition instrument 52, and the monitoring instrument can monitor the data of the test model, and the data acquisition instrument 52 is connected to the monitoring instrument data and can transmit and process data.

[0042] In this embodiment, the surrounding rock model consists of an outer rock block 11 and an inner salt block 12. The outer rock block 11 is in close contact with the inner salt block 12, thereby ensuring load transfer. A circular hole is reserved in the center of the outer rock block 11. The outer rock block 11 has a square cross-section, with a thickness less than the side length of the square cross-section. The circular hole in the outer rock block 11 is filled with an annular inner salt block 12, which has a cylindrical cavity 13 and a thickness consistent with that of the outer rock block 11.

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

[0044] like Figure 2-4 As 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 plugs are respectively arranged on both sides of the cavity 13 along the axial direction. The side of the sealing plug facing the cavity 13 is sequentially provided with an insulation layer 171 and a sealing layer 133. The sealing layer 133 is made of materials such as rubber or fiberglass. The rigid connecting rod 19 passes through the cavity 13 and connects to the sealing plugs and restraining disk 18 on both sides. The restraining disk 18 is located on the side of the sealing plug facing away from the cavity 13 and can directly or indirectly abut 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, and 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. The loading plates 22 are directly or indirectly connected to the ground stress loading system and bear the load.

[0046] like Figure 3 and Figure 4 As shown, in a specific embodiment, the fixing plate 15 is provided with a through hole 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 provided between the sealing plug and the hole wall of the through hole, the restraint disk 18 is located on the outside of the fixing plate 15 and can abut against the fixing plate 15; a triangular fixing seat 16 is provided between the load-bearing base 14 and the fixing plate 15.

[0047] Specifically, if Figure 2As shown, the test model has a load-bearing base 14 at the bottom, loading plates 22 at the top and on two opposing sides, and fixed plates 15 on the front and back. The fixed plates 15 are recessed into the base and flanked by triangular fixings 16. The salt cave model is based on the cavity 13 of the internal salt block 12. Sealing plugs are installed at both ends of the cavity. The sealing plugs have an insulating layer 171 and a sealing layer 133 on one side of the cavity to prevent the salt cavern temperature from transmitting from one end to the other and ensure a tight seal. A circular hole is reserved in the center of the fixed plate 15, and a sealing ring 172 is installed on the wall of the reserved hole. Outside the sealing plug is a restraining plate 18, which is larger than the circular hole reserved in the fixed plate 15. A rigid connecting rod 19 passes through the center of the cavity and is secured with bolts 191, thus forming a sealed unit with the restraining plate 18, fixed plate 15, sealing plug, and test model. With both ends fixed in this way, 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. It also allows the surrounding rocks to bear the load, restores the plane strain stress state, and ensures 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 via a line pipeline. One end of the hydraulic head 21 abuts the loading frame 23, and the other end abuts 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. Different pressure values ​​can be applied to the top and left and right sides, reflecting different lateral 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 instruments include 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, there are multiple cavity wall temperature monitors 513, 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; there are multiple surrounding rock strain monitors 515 and surrounding rock temperature detectors 516, 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 in 6 groups, and the monitoring depth reaches the contact seam between the two salt rocks, and the peripheral salt layer is not monitored. The monitoring instrument is connected to the data acquisition device 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 inlet pipe 33 and an outlet pipe 37. The inlet pipe 33 connects the cavity 13 with the high-pressure gas source, and the outlet pipe 37 connects the cavity 13 with the air purifier 38. The inlet pipe 33 is equipped with a compressor 31, a heat exchanger 32, a first valve 34, a first flowmeter 35, and a pressure gauge 36, while the outlet pipe 37 is equipped 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 installed in the brine delivery pipe 41, and a filter is installed at the pipe mouth of the brine delivery pipe 41.

[0051] To maintain the flow of gas and the increase and decrease of brine, a gas delivery pipe string 134 and a brine delivery pipe string 135 are reserved at one axial end of the internal salt block 12. These pipe strings pass through the sealing plug and the restraining disk 18 to connect to the outside. The gas delivery pipe string 134 is connected to the air circulation and discharge system, and the brine delivery pipe string 135 is connected to the brine extraction system. Furthermore, the rigid connecting rod 19, the contact points between the pipe string and the sealing plug are sealed, forming a sealed salt chamber in the cavity 13. Sediment 131 is obtained by immersion and crushing the interlayer on site, and saturated brine 132 is obtained by dissolving salt layers sampled on site, or brine is prepared in the laboratory to reach saturation to ensure that the internal salt block 12 will not be further dissolved. The original volume of the cavity 13 and the volume of the sediment 131 can be determined, and the gas storage volume of the salt chamber can be calculated from the volume of the brine. These volume data serve as basic parameters for subsequent experimental research.

[0052] In this embodiment, a high-pressure gas source provides compressed air at a specific temperature and pressure via a compressor 31 and a heat exchanger 32. An inlet line 33 is connected to one end of the high-pressure gas source. Once compressed, the gas flows through this line into the cavity 13 of the internal salt block 12, injecting the gas into the cavity 13. A first valve 34 controls the flow rate, and a first flow meter and a pressure gauge 36 monitor and record the gas flow rate and pressure. An outlet line 37, connected to a purifier 38, forms an outlet pipe. The compressed gas within the cavity 13 passes through the outlet line 37 and is desalinated by the purifier 38 before being released. A second valve and a second flow meter are provided on the outlet pipe. The air circulation system generates a source of air at a specific pressure and temperature from the compressor 31 via the heat exchanger 32, which is then fed into the cavity 13 of the internal salt block 12. This ensures a tight seal between the internal salt block 12 and the salt cavern model within a pressure range of 8 MPa.

[0053] The brine delivery pipe 41, used for brine extraction, connects the liquid storage container 43 and the cavity 13, with a third valve 42 in between for opening and closing control. The pipe column (brine delivery pipe 41) in the cavity 13 is lowered to the bottom and equipped with a filter to prevent sediment 131 from clogging the pipe column. The liquid storage container 43 has a precise scale to accurately measure the brine volume. Brine is injected through the height difference between the liquid storage container 43 and the salt cavern and discharged through compressed air pressure.

[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 of the first aspect of the embodiment to perform a simulation test. 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 predetermined height, and the salt cavern model is adjusted to seal the cavity 13 and form a closed space;

[0056] Open the valve of the brine extraction system and inject brine to a preset height in the cavity 13. Close the valve and record the volume of brine flowing in. Then calculate the gas storage volume using the original volume of the cavity 13, the volume of the sediment 131 and the volume of the brine.

[0057] Open the air inlet valve of the air circulation charging and discharging system, inject compressed air into the cavity 13, and record the gas injection flow rate and pressure. 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 can be done with or without applying 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] This test system allows for comparative tests of compressed air energy storage under different sediment 131 brine schemes. By comparing temperature, pressure, and stress data from 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 tested in sequence;

[0061] When testing one test model, the amount of sediment 131 added was half the volume of the cavity 13 and no brine was added; when testing another test model, the amount of sediment 131 added was half the volume of the cavity 13 and brine was added; when testing the third test model, the amount of sediment 131 and brine added was half 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 sediment 131 in the cavity but no brine, sample 2 carried out a test with the same amount of sediment 131 as sample 1 and brine, and sample 3 carried out a test with only half the sediment 131 and brine as sample 2.

[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 rate, 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), the brine pipe valve is closed, and gas injection is continued until the cavity reaches the preset pressure, and the gas injection pipe valve is closed. Record the amount of gas injected (kg) during this process, and the monitoring data of the cavity, cavity wall, and brine temperature. 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] During the Specimen 2 test, the brine was maintained just above the sediment 131 during the gas injection and brine removal phase (simulating traditional gas injection and brine removal). The tubing valve was then closed, and the compressed air injection and production process was continued at the same rate, with monitoring data recorded during the process. For Specimen 3, the procedures of Specimen 2 were essentially repeated, with the exception of the location of the brine discharge. The monitoring data from the three schemes were compared and analyzed to assess the impact of brine and sediment 131 on compressed air storage performance and surrounding rock stability, as well as the advantages and disadvantages of different gas injection storage modes, and to provide engineering construction recommendations.

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

[0067] As can be seen from the above examples, the salt cavern compressed air energy storage simulation test system and experimental method in the embodiments of the present application can use on-site salt cores and interlayers as test models, and obtain the heat transfer parameters and mechanical parameters of the salt layer, brine, and sediment 131 based on monitoring data, providing 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 impact of temperature on the mechanical properties of the salt cavern, evaluate the temperature effect, and whether to take relevant measures; it can also carry out gas injection and brine removal process simulation to provide a reference for the optimal rate of gas injection and brine removal, or conduct short-term and long-term cyclic charging and discharging tests to provide a basis for the stability of the salt cavern under short-term and long-term cyclic injection and production; it can also carry out comparative tests under various sediment 131 and brine volumes to evaluate the impact of brine and sediment 131 on compressed air storage performance and surrounding rock stability, providing support for the optimal solution for actual engineering. It can reveal the coupling mechanism of the four major media 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 compressed air storage. The stress on the test system is approximately a plane strain model, which is different from the three-dimensional stress in a real salt cavern. However, this plane strain system is simple to understand, easy to operate and implement, and also facilitates the comparison of test results with theoretical models.

[0068] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A salt cavern compressed air energy storage simulation test system, characterized in that: include: A test model, the test model comprising a surrounding rock model and a salt cave model, the surrounding rock model comprising an outer rock block and an inner salt block, the outer rock block being disposed outside the inner salt block and in close contact with the inner salt block for load transfer, the inner salt block having a cylindrical cavity extending axially along and penetrating the inner salt block; the salt cave model being at least partially disposed on both sides of the inner salt block along the axial direction, the salt cave model being capable of sealing the cavity and transferring the load borne by the inner salt block to the outer rock block; a ground stress loading system, wherein the ground stress loading system is capable of applying a load from the outer rock blocks to the inner salt blocks 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 in communication with the cavity and is capable of conveying and monitoring high-pressure gas, and the brine pumping and discharging system is in communication with the cavity and is capable of conveying and monitoring brine; The data monitoring and acquisition system includes a monitoring instrument and a data acquisition device. The monitoring instrument can monitor the data of 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 includes a sealing plug, a rigid connecting rod, and a restraining disk. The sealing plugs are respectively arranged on both sides of the cavity along the axial direction, and the side of the sealing plug facing the cavity is sequentially provided with an insulation layer and a sealing layer. The rigid connecting rod passes through the cavity and is connected to the sealing plugs and the restraining disk on both sides. The restraining disk is located on the side of the sealing plug facing away from the cavity, and the restraining disk can directly or indirectly abut 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 plates are directly or indirectly connected to the ground stress loading system and bear 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 portion 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 disk 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.

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 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.

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 center 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 monitor and the surrounding rock temperature detector is multiple, and the multiple surrounding rock strain monitors and the surrounding rock temperature detectors are arranged in the internal salt block in a 60° circular manner in 6 groups.

7. The salt cavern compressed air energy storage simulation test system according to claim 6 is characterized in that: The air circulation 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 to 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 according to any one of claims 1 to 8 to perform a simulation test, and the salt cavern compressed air energy storage simulation test method includes the following steps: The test model is fabricated and assembled to form a cavity of known size, sediment of known volume is laid in the cavity to a predetermined 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 brine flowing in, and then calculate the gas storage volume based on the original volume of the cavity, the volume of sediment, and the volume of brine; Open the air inlet valve of the air circulation charging and discharging system, inject compressed air into the cavity, record the gas injection flow rate 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 can be done with or without applying ground stress. When applying ground stress, data monitoring of surrounding rock strain is added; 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 tested in sequence; 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 third 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 compressed air storage performance and surrounding rock stability, as well as the advantages and disadvantages of different gas injection storage modes.

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