Liquid CO2 pressure injection device for coal seam pressure relief in coal mine tunnel tunneling

Abstract

The utility model discloses a liquid CO2 pressure injection device for coal seam pressure relief in coal mine tunnel tunneling, which belongs to the technical field of coal mine gas control and comprises a bottom plate, a plurality of supporting columns are mounted on the periphery of the bottom plate in a welding manner, and a top plate is mounted right above the supporting columns in a welding manner. A first supporting rod and a second supporting rod are installed between the two supporting columns right in front of the bottom plate in a welded mode, and by installing monitoring components such as a temperature transmitter and a pressure transmitter and conveying components such as a low-temperature liquid CO2 conveying pipe, relevant data of liquid CO2 under different temperatures and pressures can be accurately obtained; and the permeability evolution law, the phase change fracturing effective displacement radius and the like of the coal seam are deeply analyzed. Therefore, the purpose of comprehensively and deeply analyzing the complex action mechanism of the liquid CO2 in the coal seam is achieved, a solid theoretical basis and accurate practical guidance are provided for scientific application of the liquid CO2 in coal seam gas control, and the effect of optimizing a gas control scheme is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of coal mine gas control, in particular to a liquid CO2 injection device for decompression of coal seams during tunneling in coal mines. Background Art

[0002] In coal mining, gas emissions remain a significant threat to safe production, and the low efficiency of traditional gas extraction technologies urgently needs to be addressed. Liquid carbon dioxide offers significant advantages in this context. Its phase-change cracking properties can enhance coal seam permeability. Furthermore, due to the different adsorption capacities of carbon dioxide and methane on the coal surface, it can effectively displace methane, facilitating gas extraction. This has led to the development of a range of supporting devices.

[0003] The existing patent publication number is CN207438132U, which discloses a liquid carbon dioxide injection device, including a first-stage booster pump, the input end of the first-stage booster pump is connected to the liquid carbon dioxide source, the liquid output end of the first-stage booster pump is connected to the input end of the buffer tank, and the gaseous output end of the first-stage booster pump is connected to an exhaust pump; the output end of the buffer tank is connected to the input end of the second-stage booster pump, and the output end of the second-stage booster pump is connected to the product production line. The two-stage boosting method is used to reduce the possibility of vaporization of liquid carbon dioxide during the injection process. The exhaust pump can extract the vaporized carbon dioxide in the first-stage booster pump to ensure the purity of the liquid carbon dioxide in the delivery pipeline.

[0004] Existing liquid carbon dioxide injection devices have exposed many shortcomings. They focus on solving the problem of vaporization of liquid carbon dioxide during transportation and ensuring its purity. Specifically, this goal is achieved through the cooperation of a first-stage booster pump, a buffer tank, a second-stage booster pump, and a vacuum pump. However, compared with our goal of achieving efficient gas control with the help of liquid carbon dioxide, there are significant deficiencies and uncertainties, because the device itself does not have the corresponding research or monitoring functions. In addition, the device does not propose a technical system for the fusion of liquid CO2 phase change fracturing, pressure relief, and permeability enhancement of coal seams and displacement and gas extraction, nor can it establish an effect evaluation model based on indicator parameters, resulting in a lack of systematic guidance and effect evaluation for the entire injection process, which is not conducive to the further optimization and application of the technology. To this end, we propose a liquid CO2 injection device for coal seam pressure relief in coal mine tunnel excavation to solve the above-mentioned problems. Utility Model Content

[0005] The purpose of this section is to summarize some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and in the abstract and title of the present invention to avoid obscuring the purpose of this section, the abstract and the title of the utility model, and such simplifications or omissions shall not be used to limit the scope of the present invention.

[0006] Therefore, the purpose of this utility model is to provide a liquid CO2 injection device for decompression of coal seams in coal mine tunnel excavation, which can solve the many shortcomings exposed by existing liquid carbon dioxide injection devices. It focuses on solving the problem of vaporization of liquid carbon dioxide during transportation and ensuring its purity. Specifically, this goal is achieved through the cooperation of a primary booster pump, a buffer tank, a secondary booster pump and a vacuum pump. However, compared with our goal of achieving efficient gas control with the help of liquid carbon dioxide, there are significant shortcomings and the relationship cannot be determined because the device itself does not have the corresponding research or monitoring function. In addition, the device does not propose a technical system for the fusion of liquid CO2 phase change fracturing, decompression and permeability enhancement of coal seams and displacement and gas extraction, nor can it establish an effect evaluation model based on indicator parameters, which makes the entire injection process lack systematic guidance and effect evaluation, which is not conducive to the further optimization and application of the technology.

[0007] In order to solve the above technical problems, the present invention provides a liquid CO2 injection device for decompressing coal seams in coal mine tunnel excavation, which adopts the following technical solution: it includes a base plate, a plurality of pillars are installed around the base plate by welding, a top plate is welded and installed directly above the pillars, a first support rod and a second support rod are welded between two support columns directly in front of the base plate, the first support rod is located directly above the second support rod, a large buffer box is fastened and installed directly above the base plate, a first cryogenic pump skid and a second cryogenic pump skid are fastened and installed directly in front of the large buffer box, and the first cryogenic pump skid is located directly to the left of the second cryogenic pump skid.

[0008] Optionally, a first fastener is fastened and installed directly above the second support rod, a low-temperature liquid CO2 delivery pipe is fastened and installed directly in front of the first low-temperature pump skid and the second low-temperature pump skid, the tail of the low-temperature liquid CO2 delivery pipe is fixed to the first fastener, and a liquid inlet is opened at the tail of the low-temperature liquid CO2 delivery pipe.

[0009] Optionally, a first support frame is welded and installed directly above the base plate, the first support frame is located outside the first cryogenic pump skid and the second cryogenic pump skid, a second fastener is fastened and installed directly above the first support rod, and a liquid CO2 gasification return pipe is fastened and installed directly above the first cryogenic pump skid and the second cryogenic pump skid.

[0010] Optionally, the tail end of the liquid CO2 gasification return pipe is fixed to a second fastener, a return gas port is opened at the tail end of the liquid CO2 gasification return pipe, a first temperature transmitter is fastened and installed directly above the liquid CO2 gasification return pipe, a three-way regulating valve is fastened and installed directly to the right of the first support frame, and a second temperature transmitter is fastened and installed directly behind the second support rod.

[0011] Optionally, a first transmission hose is fixedly installed right behind the first temperature transmitter, the first transmission hose is connected to the three-way regulating valve right above, a second transmission hose is fixedly installed right above the three-way regulating valve, and the second transmission hose is connected to the second temperature transmitter right above.

[0012] Optionally, a second support frame is welded and installed right above the bottom plate, the second support frame is located right above the second low-temperature pump sled, a first pressure lead pipe is fixedly installed on the second support frame, a pressure transmitter is fixedly installed right above the first pressure lead pipe, and a pressure pipe collection module is fixedly installed right below the first pressure lead pipe.

[0013] Optionally, a second pressure lead pipe is fixedly installed right above the first low-temperature pump sled, a third pressure lead pipe is fixedly installed right above the second low-temperature pump sled, a fourth pressure lead pipe is fixedly installed right below the three-way regulating valve, and the second pressure lead pipe, the third pressure lead pipe and the fourth pressure lead pipe are connected to the pressure pipe collection module right below after being converged into a single pipe.

[0014] Optionally, a first transmission pipe is fixedly installed right behind the second support rod, the second temperature transmitter is connected to the first transmission pipe, the first transmission pipe is divided into a second transmission pipe and a fifth pressure lead pipe at the tail, a check valve is fixedly installed on the second transmission pipe, and an outlet is formed right left of the second transmission pipe.

[0015] Optionally, a central control box is fixedly installed right above the bottom plate, the central control box is located right above the large buffer tank, a temperature display and a pressure display are installed on the central control box, a plurality of control buttons are fixedly installed right below the temperature display and the pressure display, and a pump start indicator and a pump stop indicator are fixedly installed right below the control buttons.

[0016] In summary, the utility model has at least one of the following beneficial effects:

[0017] 1. By installing monitoring components such as temperature transmitters, pressure transmitters and the like and conveying components such as low-temperature liquid CO2 conveying pipes and the like, relevant data of liquid CO2 under different temperature and pressure can be accurately obtained, and the evolution law of the permeability of liquid CO2 in the coal seam, the effective displacement radius of phase change fracturing and the like can be deeply analyzed, so that the purpose of comprehensively and deeply analyzing the complex action mechanism of liquid CO2 in the coal seam is achieved, a solid theoretical basis and accurate practical guidance for scientific application of liquid CO2 in coal seam gas control are provided, and the effect of optimizing the gas control scheme is realized.

[0018] 2. By installing control components such as three-way regulating valves and central control boxes, as well as manifold modules and other manifolds, the flow direction of liquid CO2 can be flexibly adjusted and injection parameters can be precisely controlled based on monitoring data. This allows for precise control of the area and method of liquid CO2's action within the coal seam, effectively optimizing gas control solutions and achieving results such as increasing the effective control radius, increasing the extraction flow rate, and extending the active extraction period. This effectively ensures safe production in coal mines and reduces production stagnation and safety accidents caused by gas problems. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0020] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0021] Figure 2 This is a schematic diagram of the overall left front structure of the utility model;

[0022] Figure 3 It is a partial cross-sectional structural schematic diagram of the utility model;

[0023] Figure 4 It is a schematic diagram of the local structure of the utility model;

[0024] Figure 5 This is a schematic diagram of the central control box of the present utility model.

[0025] Explanation of reference numerals: 1. bottom plate; 2. pillar; 3. top plate; 4. first support rod; 5. second support rod; 6. large buffer tank; 7. first cryogenic pump skid; 8. second cryogenic pump skid; 9. first fastener; 10. cryogenic liquid CO2 delivery pipe; 11. liquid inlet; 12. first support frame; 13. second fastener; 14. liquid CO2 gasification return pipe; 15. return gas port; 16. first temperature transmitter; 17. three-way regulating valve; 18. second temperature transmitter; 19. first transmission soft Tube; 20. Second transmission hose; 21. Second support frame; 22. First pressure-conducting pipe; 23. Pressure transmitter; 24. Pressure pipe collection module; 25. Second pressure-conducting pipe; 26. Third pressure-conducting pipe; 27. Fourth pressure-conducting pipe; 28. First transmission pipe; 29. ​​Second transmission pipe; 30. Fifth pressure-conducting pipe; 31. Central control box; 32. Temperature display; 33. Pressure display; 34. Control button; 35. Pump start indicator light; 36. Pump stop indicator light; 37. One-way valve; 38. Outlet. DETAILED DESCRIPTION

[0026] The following is combined with Figure 1 —5 The utility model is further described in detail.

[0027] Example 1, refer to Figures 1-5 The utility model discloses a liquid CO2 injection device for decompressing coal seams in coal mine tunnel excavation, comprising a bottom plate 1, a plurality of pillars 2 are installed around the bottom plate 1 by welding, a top plate 3 is welded and installed directly above the pillars 2, a first support rod 4 and a second support rod 5 are welded between the two support pillars directly in front of the bottom plate 1, the first support rod 4 is located above the second support rod 5, a large buffer box 6 is fastened and installed directly above the bottom plate 1, a first cryogenic pump skid 7 and a second cryogenic pump skid 8 are fastened and installed directly in front of the large buffer box 6, the first cryogenic pump skid 7 is located directly to the left of the second cryogenic pump skid 8, by welding the pillars 2 around the bottom plate 1, welding the top plate 3 above the pillars 2, installing the first and second support rods 5 distributed up and down between the support pillars directly in front of the bottom plate 1, installing the large buffer box 6 above the bottom plate 1, and connecting the first and second cryogenic pump skids 8 in front of the large buffer box 6, the purpose of stabilizing the device structure is achieved, and stable support and reasonable layout are provided for liquid CO2 injection related equipment, ensuring the safe operation of the equipment and easy operation.

[0028] A first fastener 9 is fastened and installed directly above the second support rod 5, and a low-temperature liquid CO2 delivery pipe 10 is fastened and installed directly in front of the first cryogenic pump skid 7 and the second cryogenic pump skid 8. The tail end of the low-temperature liquid CO2 delivery pipe 10 is fixed to the first fastener 9, and a liquid inlet 11 is provided at the tail end of the low-temperature liquid CO2 delivery pipe 10. By installing the first fastener 9 directly above the second support rod 5, and fixing the tail end of the low-temperature liquid CO2 delivery pipe 10 connecting the first cryogenic pump skid 7 and the second cryogenic pump skid 8 to the first fastener 9 and providing the liquid inlet 11, the purpose of stabilizing the position of the delivery pipe and standardizing the liquid inlet is achieved, thereby ensuring the stable delivery of liquid CO2, facilitating the connection of other components, and ensuring smooth liquid inlet.

[0029] A first support frame 12 is welded and installed directly above the base plate 1. The first support frame 12 is located outside the first cryogenic pump skid 7 and the second cryogenic pump skid 8. A second fastener 13 is fastened and installed directly above the first support rod 4. A liquid CO2 gasification return pipe 14 is fastened and installed directly above the first cryogenic pump skid 7 and the second cryogenic pump skid 8. By welding the first support frame 12 located outside the first cryogenic pump skid 7 and the second cryogenic pump skid 8 directly above the base plate 1, installing the second fastener 13 directly above the first support rod 4, and installing the liquid CO2 gasification return pipe 14 directly above the first cryogenic pump skid 7 and the second cryogenic pump skid 8, the purpose of stabilizing the pump skid structure and standardizing the installation of the return pipe is achieved, thereby enhancing the stability of the device and ensuring the smooth return of liquid CO2 after vaporization.

[0030] The tail end of the liquid CO2 gasification return pipe 14 is fixed to the second fastener 13, and a return gas port 15 is opened at the tail end of the liquid CO2 gasification return pipe 14. A first temperature transmitter 16 is fastened and installed directly above the liquid CO2 gasification return pipe 14, a three-way regulating valve 17 is fastened and installed directly to the right of the first support frame 12, and a second temperature transmitter 18 is fastened and installed directly behind the second support rod 5. By fixing the tail end of the liquid CO2 gasification return pipe 14 to the second fastener 13 and opening the return gas port 15, installing the first temperature transmitter 16 directly above the gasification return pipe, installing the three-way regulating valve 17 directly behind the first support frame 12, and installing the second temperature transmitter 18 directly behind the second support rod 5, the purpose of stabilizing the gasification return pipe, facilitating gas reflux monitoring and control, and real-time temperature monitoring is achieved, thereby ensuring the stability of the gasification return process, flexibly adjusting the gas flow direction, and accurately grasping the temperature changes.

[0031] A first transmission hose 19 is fastened and installed directly behind the first temperature transmitter 16, and the first transmission hose 19 is connected to directly above the three-way regulating valve 17. A second transmission hose 20 is fastened and installed directly to the right of the three-way regulating valve 17, and the second transmission hose 20 is connected to directly to the right of the second temperature transmitter 18. By installing the first transmission hose 19 directly behind the first temperature transmitter 16 and connecting it to directly above the three-way regulating valve 17, and installing the second transmission hose 20 directly to the right of the three-way regulating valve 17 and connecting it to directly to the right of the second temperature transmitter 18, the purpose of establishing a stable connection channel is achieved, and the effect of smooth transmission of the medium and effective conduction of signals between the temperature transmitter and the three-way regulating valve 17 is achieved.

[0032] A second support frame 21 is welded and installed directly above the base plate 1. The second support frame 21 is located directly to the right of the second cryogenic pump skid 8. A first pressure-leading pipe 22 is fastened and installed on the second support frame 21. A pressure transmitter 23 is fastened and installed directly above the first pressure-leading pipe 22. A pressure pipe collection module 24 is fastened and installed directly below the first pressure-leading pipe 22. By welding and installing the second support frame 21 directly above the base plate 1 and directly to the right of the second cryogenic pump skid 8, installing the first pressure-leading pipe 22 thereon, and installing the pressure transmitter 23 and the pressure pipe collection module 24 above and below the first pressure-leading pipe 22 respectively, the purpose of rationally arranging the pressure-related components is achieved, and the effect of stably transmitting pressure signals and effectively collecting pressure data for accurate measurement and monitoring of pressure conditions is achieved.

[0033] A second pressure-inducing pipe 25 is fastened and installed directly above the first cryopump skid 7, a third pressure-inducing pipe 26 is fastened and installed directly above the second cryopump skid 8, and a fourth pressure-inducing pipe 27 is fastened and installed directly below the three-way regulating valve 17. The second pressure-inducing pipe 25, the third pressure-inducing pipe 26, and the fourth pressure-inducing pipe 27 are converged into a single pipe and then connected to the left side of the pressure pipe collection module 24. By installing the second pressure-inducing pipe 25 directly above the first cryopump skid 7, the third pressure-inducing pipe 26 directly above the second cryopump skid 8, and the fourth pressure-inducing pipe 27 directly below the three-way regulating valve 17, and converging the second pressure-inducing pipe 25, the third pressure-inducing pipe 26, and the fourth pressure-inducing pipe 27 into a single pipe and then connecting it to the left side of the pressure pipe collection module 24, the purpose of integrating the pressure-inducing channels is achieved, and the effect of centralized collection of pressure data from different parts and convenient unified monitoring and analysis of pressure conditions is realized.

[0034] A first transmission pipe 28 is fastened and installed directly behind the second support rod 5, the tail of the second temperature transmitter 18 is connected to the first transmission pipe 28, and the tail of the first transmission pipe 28 is diverted to form a second transmission pipe 29 and a fifth pressure-inducing pipe 30, a one-way valve 37 is fastened and installed on the second transmission pipe 29, and an outlet 38 is opened on the left side of the second transmission pipe 29. By installing the first transmission pipe 28 directly behind the second support rod 5, and connecting the tail of the second temperature transmitter 18 to the first transmission pipe 28, and the tail of the first transmission pipe 28 is diverted to form the second transmission pipe 29 and the fifth pressure-inducing pipe 30, installing a one-way valve 37 on the second transmission pipe 29 and setting the outlet 38, the purpose of constructing a reasonable transmission and diversion channel is achieved, and the effect of ensuring that the medium is transmitted in a specific direction, preventing backflow, and can be output or discharged through the outlet 38 is realized.

[0035] A central control box 31 is fastened and installed just above the base plate 1. The central control box 31 is located just to the right of the large buffer tank 6. A temperature display 32 and a pressure display 33 are installed on the central control box 31. Several control buttons 34 are fastened and installed just below the temperature display 32 and the pressure display 33. A pump start indicator light 35 and a pump stop indicator light 36 are fastened and installed just below the control button 34. By installing the central control box 31 just above the base plate 1 and just to the right of the large buffer tank 6, and installing the temperature display 32 and the pressure display 33 on the central control box 31, and installing the control buttons 34, the pump start indicator light 35 and the pump stop indicator light 36 below them, the purpose of centralized display and control of relevant parameters and equipment status is achieved, and it is convenient for operators to understand the temperature and pressure conditions in real time, conveniently control the operation of the equipment and accurately know the working status of the pump.

[0036] The specific operating principle is as follows: By installing monitoring components such as temperature transmitters and pressure transmitters 23, as well as delivery components such as low-temperature liquid CO2 delivery pipes, accurate data on liquid CO2 at different temperatures and pressures can be obtained, enabling in-depth analysis of its permeability evolution within coal seams and the effective displacement radius of phase change-induced fracturing. This allows for a comprehensive and in-depth analysis of the complex mechanisms of liquid CO2 in coal seams, providing a solid theoretical basis and precise practical guidance for the scientific application of liquid CO2 in coal seam gas control, and optimizing gas control solutions. By installing control components such as the three-way regulating valve 17 and central control box 31, as well as manifold components such as the pressure pipe manifold module 24, the flow direction of liquid CO2 can be flexibly adjusted based on monitoring data, allowing precise control of injection parameters. This allows for precise control of the area and pattern of liquid CO2's action within coal seams, effectively optimizing gas control solutions, increasing the effective control radius, improving the extraction flow rate, and extending the active extraction period. This effectively ensures safe coal mine production and reduces production stagnation and safety accidents caused by gas problems. By conducting a series of multi-dimensional key technology research, including but not limited to in-depth analysis of the effects of different injection parameters on coal seam permeability and gas extraction effects, testing the evolution of liquid CO2 permeability at different temperatures and pressures, determining the effective displacement radius of liquid CO2 phase change fracturing, and scientifically establishing an evaluation index for the effectiveness of liquid CO2 phase change fracturing pressure relief and permeability enhancement in coal seam boreholes. On this basis, we focus on a comprehensive and in-depth analysis of the distribution of liquid CO2 phase change fracturing stress fields within coal seams, while closely considering the changes in coal seam support pressure. In this way, we can clearly reveal the laws of phase change displacement and gas extraction promotion of liquid CO2 in coal seam boreholes, and accurately grasp the corresponding relationship between injection parameters and displacement radius. Then, we propose a complete technical system for the integration of liquid CO2 phase change fracturing pressure relief and permeability enhancement in coal seams and displacement and gas extraction promotion, and establish an effect evaluation model based on indicator parameters. Through the implementation of the above scheme, the goal of comprehensively and deeply analyzing the complex mechanism of liquid CO2 in coal seams can be achieved from the perspective of technical effects, providing a solid theoretical basis and precise practical guidance for the scientific application of liquid CO2 in coal seam gas control. This will effectively optimize the gas control scheme, significantly improve the efficiency and safety of gas control, and minimize the impact of gas disasters on coal mine production. In addition, by building a complete set of coal mine coal seam gas control system equipment and supporting process technology system, further determining the parameters for the combined use of key technologies, and continuously optimizing the process technology parameters, the effect of increasing the effective control radius, increasing the extraction flow rate, and extending the active extraction period can be achieved, ultimately fundamentally improving the level of coal mine gas control, effectively ensuring coal mine safety production, and effectively reducing production stagnation and safety accidents caused by gas problems.

[0037] The above are all preferred embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A liquid CO2 injection device for decompression of coal seams during tunneling in a coal mine, comprising a bottom plate (1), characterized in that: A plurality of pillars (2) are installed around the base plate (1) by welding, a top plate (3) is welded and installed directly above the pillars (2), a first support rod (4) and a second support rod (5) are welded and installed between two support columns directly in front of the base plate (1), the first support rod (4) is located directly above the second support rod (5), a large buffer box (6) is fastened and installed directly above the base plate (1), a first cryogenic pump skid (7) and a second cryogenic pump skid (8) are fastened and installed directly in front of the large buffer box (6), and the first cryogenic pump skid (7) is located directly to the left of the second cryogenic pump skid (8).

2. The liquid CO2 injection device for decompression of coal seams during tunneling in a coal mine according to claim 1, characterized in that: A first fastener (9) is fastened and installed directly above the second support rod (5); a low-temperature liquid CO2 delivery pipe (10) is fastened and installed directly in front of the first low-temperature pump skid (7) and the second low-temperature pump skid (8); the tail of the low-temperature liquid CO2 delivery pipe (10) is fixed to the first fastener (9); and a liquid inlet (11) is provided at the tail of the low-temperature liquid CO2 delivery pipe (10).

3. The liquid CO2 injection device for decompression of coal seams during tunneling in a coal mine according to claim 1, characterized in that: A first support frame (12) is welded and installed directly above the base plate (1), and the first support frame (12) is located outside the first cryogenic pump skid (7) and the second cryogenic pump skid (8). A second fastener (13) is fastened and installed directly above the first support rod (4), and a liquid CO2 gasification return pipe (14) is fastened and installed directly above the first cryogenic pump skid (7) and the second cryogenic pump skid (8).

4. The liquid CO2 injection device for decompression of coal seams during tunneling in a coal mine according to claim 3, characterized in that: The tail of the liquid CO2 gasification return pipe (14) is fixed to the second fastener (13), and a return air port (15) is provided at the tail of the liquid CO2 gasification return pipe (14). A first temperature transmitter (16) is fastened and installed directly above the liquid CO2 gasification return pipe (14), a three-way regulating valve (17) is fastened and installed directly to the right of the first support frame (12), and a second temperature transmitter (18) is fastened and installed directly behind the second support rod (5).

5. The liquid CO2 injection device for decompression of coal seams during tunneling in a coal mine according to claim 4, characterized in that: A first transmission hose (19) is fastened and installed directly behind the first temperature transmitter (16), and the first transmission hose (19) is connected to directly above the three-way regulating valve (17). A second transmission hose (20) is fastened and installed directly to the right of the three-way regulating valve (17), and the second transmission hose (20) is connected to directly to the right of the second temperature transmitter (18).

6. The liquid CO2 injection device for decompression of coal seams during tunneling in a coal mine according to claim 1, characterized in that: A second support frame (21) is welded and installed directly above the base plate (1). The second support frame (21) is located directly to the right of the second cryogenic pump skid (8). A first pressure-inducing pipe (22) is fastened and installed on the second support frame (21). A pressure transmitter (23) is fastened and installed directly above the first pressure-inducing pipe (22). A pressure pipe collection module (24) is fastened and installed directly below the first pressure-inducing pipe (22).

7. The liquid CO2 injection device for decompression of coal seams during tunneling in a coal mine according to claim 5, characterized in that: A second pressure-inducing pipe (25) is fastened and installed directly above the first cryogenic pump skid (7), a third pressure-inducing pipe (26) is fastened and installed directly above the second cryogenic pump skid (8), and a fourth pressure-inducing pipe (27) is fastened and installed directly below the three-way regulating valve (17). The second pressure-inducing pipe (25), the third pressure-inducing pipe (26) and the fourth pressure-inducing pipe (27) are converged into a single pipe and connected to the left side of the pressure pipe collection module (24).

8. The liquid CO2 injection device for decompression of coal seams during tunneling in a coal mine according to claim 5, characterized in that: A first transmission pipe (28) is fastened and installed directly behind the second support rod (5); the tail of the second temperature transmitter (18) is connected to the first transmission pipe (28); the tail of the first transmission pipe (28) is split to form a second transmission pipe (29) and a fifth pressure-inducing pipe (30); a one-way valve (37) is fastened and installed on the second transmission pipe (29); and an outlet (38) is opened directly to the left of the second transmission pipe (29).

9. The liquid CO2 injection device for decompression of coal seams during tunneling in a coal mine according to claim 1, characterized in that: A central control box (31) is fastened and installed just above the base plate (1). The central control box (31) is located just to the right of the large buffer box (6). A temperature display (32) and a pressure display (33) are installed on the central control box (31). A plurality of control buttons (34) are fastened and installed just below the temperature display (32) and the pressure display (33). A pump start indicator light (35) and a pump stop indicator light (36) are fastened and installed just below the control buttons (34).

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