CN114517707A - Liquid CO for spontaneous combustion of coal and gas disaster in underground coal mine2Comprehensive prevention and control mode - Google Patents

Abstract

In the comprehensive prevention and control mode of liquid CO ₂ for spontaneous combustion of coal and gas disasters in coal mines disclosed by the invention, the arrangement of the long-distance transportation system for liquid CO ₂ is determined according to the mine excavation project plan, the ventilation system diagram and the comparison diagram of the upper and lower mines, and the liquid CO ₂ is passed through the conveying pipe. The net is led to the required fire-proof goaf and the coal seam anti-permeability working face, and the liquid CO ₂ can also be led to other mining areas through pipelines. The method of the invention adopts one medium (liquid CO ₂ ) to realize the effective prevention and control of the two disasters, breaks through the previous traditional mode of separate prevention and control of the two disasters, shortens the transportation time of CO ₂ , and improves the prevention and control efficiency of the two disasters .

Description

Comprehensive prevention and control mode of liquid CO2 for coal spontaneous combustion and gas disaster in coal mines

technical field

The invention belongs to the technical field of coal mine safety, and in particular relates to a liquid CO ₂ comprehensive prevention and control mode for coal spontaneous combustion and gas disasters in underground coal mines.

Background technique

With the continuous extension of the mining depth of the mine and the continuous deterioration of the mining conditions, especially in the deep mining stage, it will face the comprehensive effects of the "three highs and one low" phenomena of high ground stress, high gas, high ground temperature and low permeability. High in-situ stress makes the coal and rock fragmentation large, and a large number of air leakage cracks and channels are formed on the coal-rock wall of the roadway, which provides oxygen supply and heat storage conditions for spontaneous ignition; high ground temperature is conducive to the progress of coal-oxygen composite reaction and shortens the spontaneous ignition of coal. The coal seam gas content is large, the pressure is high and the permeability is low, which makes the original coal seam gas extraction difficult, and the mining face is prone to abnormal gas gushing, gas exceeding the limit, and coal and gas outbursts occur frequently. To sum up, deep mining will face dual threats of gas and coal spontaneous combustion.

In order to solve coal spontaneous combustion and low permeability coal seam gas disasters, domestic and foreign scientific research institutes have successively developed a number of coal spontaneous combustion prevention and coal seam enhancement gas drainage technologies. Coal spontaneous combustion prevention and control technologies mainly include nitrogen injection, liquid CO ₂ injection, polymer colloid, three _- phase foam, etc. Blasting, directional blasting, high-voltage electric pulse controllable shock wave blasting, CO ₂ /N ₂ flooding and other technologies.

To sum up, as an inert gas, liquid CO ₂ has the effects of preventing and controlling the spontaneous combustion of coal underground and enhancing the extraction of coal seam gas to increase the production of coal bed methane. It has been widely used in many mining areas across the country. Many mines have used liquid CO ₂ as a conventional technique for fire suppression and gas purging to increase CH ₄ production. However, at present, the liquid CO ₂ storage tanks in major mining areas are still mainly used in the size of 2.0m ³ , and the transportation methods are mainly rail vehicles and trackless rubber-tired vehicles. It is necessary to continuously transport the newly filled liquid CO ₂ to the Underground replacement cannot meet the needs at one time, the process is cumbersome and inconvenient, and it consumes manpower and material resources. In addition, as a common waste gas in industrial production, CO ₂ has a large output and low price.

Therefore, the present invention proposes a new mode of comprehensive prevention and control of coal spontaneous combustion and gas disaster in coal mines with liquid CO ₂ . The implementation of this model is not only conducive to the prevention and control of coal spontaneous combustion and gas disasters, but also provides a new idea for CO ₂ displacement of gas in closed goaf and CO ₂ storage in goaf.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a liquid CO ₂ comprehensive prevention and control mode of coal spontaneous combustion and gas disasters in coal mines, so as to realize the comprehensive prevention and control of the two major disasters by liquid CO ₂ .

_The technical scheme adopted in the present invention is that the coal mine underground coal spontaneous combustion and gas disaster liquid _CO The liquid CO ₂ is led to the fire-proof goaf and the coal seam anti-permeability working face through the pipeline network. In addition, the liquid CO ₂ can also be led to other mining areas through the pipeline.

The present invention is also characterized in that,

Specifically, follow the steps below:

Step 1. Determine the layout of the liquid CO ₂ long-distance conveying system according to the mine excavation project plan, ventilation system diagram, and the upper and lower comparison diagrams of the mine, and ensure that the liquid CO ₂ conveying pipeline is in the return air tunnel: ① If the required mining area or working face The distance from the return air shaft of the coal mine is relatively short, and the long-distance liquid CO ₂ transportation pipeline can be arranged in the return air shaft; ② If the required mining area or working face is far away from the mine return air shaft, it is necessary to pass from the ground to the required air shaft. Set up shafts at the location to complete the installation of the liquid CO ₂ delivery pipeline;

Step 2. Construct the installation foundation of the liquid CO ₂ storage tank at the location of the shaft determined in Step 1 or the selected location of the return air wellhead, and install multiple liquid CO ₂ storage tanks and 1 liquid CO ₂ storage tank on the installation foundation of the liquid CO 2 storage tank. _CO2 booster pump and 1 air temperature liquid _CO2 vaporizer, the gas phase outlets of multiple liquid _CO2 storage tanks are connected with the gas phase outlet of the liquid _CO2 booster pump through pipes; multiple liquid _CO2 storage tanks The liquid phase outlet of the liquid _CO2 booster pump is connected with the liquid phase inlet of the liquid CO2 booster pump and the inlet of the air temperature liquid _CO2 vaporizer; the outlet of the liquid _CO2 booster pump and the air temperature liquid _CO2 vaporizer are connected. The outlet leads the liquid CO ₂ to the required position downhole through the pipeline network;

Step 3. In addition to leading the liquid CO ₂ to the required fire-proof goaf and the coal seam anti-permeability working face through the pipeline network, the liquid CO ₂ can also be led to other mining areas through the pipeline;

Step 4. The conveying pipeline network includes duplex stainless steel liquid CO ₂ conveying pipelines, several liquid CO ₂ conveying branch pipes, liquid CO ₂ displacement conveying pipes along the working face return air tank, and goaf liquid CO ₂ injection pipelines ; Several liquid CO ₂ conveying branch pipes are connected with the duplex stainless steel liquid CO ₂ conveying pipeline, and one liquid CO ₂ conveying branch pipe is arranged in the return air lane of the coal mining face, and one side of the liquid CO ₂ conveying branch pipe is connected There are several liquid CO ₂ displacement conveying pipes in the return air of the working face along the tank, and several goaf liquid CO ₂ injection pipelines are connected to the other side of the liquid CO ₂ branch pipe; The CO ₂ injection pipeline and several working face return air flow down the trough liquid CO ₂ displacement conveying pipes continuously and uniformly inject liquid CO ₂ to the working face and fire-proof goaf; the remaining liquid CO ₂ conveying branch pipes are arranged in the surrounding roadways ;

Step 5. Store multiple underground mobile liquid CO ₂ storage tanks in the chamber as underground liquid CO ₂ supply substations. When other working faces or goafs in the mining area need liquid CO ₂ displacement or fire prevention, the liquid CO ₂ The supply sub-station completes the filling of the mobile storage tank and transports it to the required injection position of liquid _CO2 through the existing transportation system of the mine.

Install a self-operated pressure regulating valve at the end of the liquid CO ₂ injection pipeline in the goaf required for fire protection.

After setting the regulating valve, the pressure is greater than or equal to 0.8MPa to ensure that the _CO2 in the pressure injection pipe network is mainly carried out in the liquid phase.

The liquid CO ₂ storage tank has a volume of 25m ³ or 50m ³ .

The number of liquid _CO2 tanks is two.

The volume of the underground mobile liquid CO ₂ storage tank is 2.0 m ³ .

The beneficial effects of the present invention are:

The main equipment involved in the mode of the present invention mainly includes the surface part and the downhole part. The ground part mainly includes liquid _CO2 storage tank, liquid _CO2 booster pump and air temperature gasifier, while the downhole part mainly includes liquid _CO2 filling station, mobile liquid _CO2 storage tank, liquid _CO2 booster pump, surface The part and the downhole part are connected by a duplex stainless steel thermal insulation steel pipe. In daily production, liquid CO ₂ is regularly replenished into the ground horizontal storage tank through the liquid CO ₂ transport semi-trailer. When there is a hidden danger of coal spontaneous combustion in the mine or the CO ₂ displacement coal seam CH ₄ operation is required, the underground filling station is used. Filling the mobile storage tank and transporting it to the operation site; when a large-area goaf fire prevention operation is required, the gaseous CO ₂ is directly injected into the goaf through the ground gasifier; the filling frequency of the vertical storage tank Determine according to the actual situation.

The comprehensive prevention and control mode of the two major disasters in mines proposed by the mode of the present invention adopts one medium (liquid CO ₂ ) to realize the effective prevention and control of the two disasters, breaks through the previous traditional mode of separate prevention and control of the two disasters, and shortens the transportation of CO ₂ time, improve the prevention and control efficiency of two kinds of disasters

Description of drawings

Fig. 1 is the arrangement schematic diagram of the liquid _CO2 long-distance conveying system of the present invention;

Fig. 2 is the structural representation of the liquid _CO2 storage tank unit of the present invention;

FIG. 3 is a schematic structural diagram of the downhole liquid CO ₂ supply substation of the present invention.

In the figure, 1. Installation foundation of liquid _CO2 storage tank, 2. Liquid _CO2 storage tank, 3. Gas phase outlet of liquid _CO2 storage tank, 4. Liquid _CO2 booster pump, 5. Air-temperature liquid _CO2 gasification 6. Liquid phase inlet of liquid CO ₂ storage tank, 7. Duplex stainless steel liquid CO 2 delivery pipeline, 8. Working face return air down tank liquid CO ₂ displacement delivery pipeline, 9. Goaf liquid CO ₂ injection Pipeline, 10. Coal mine main shaft, 11. Coal mine auxiliary shaft, 12. Fire protection goaf, 13. Coal working face return airway, 14. Tunnel, 15. Coal mine return air shaft, 16. Self-operated pressure regulation valve, 17. mine level, 18. first pipe, 19 second pipe, 20. first valve, 21. second valve, 22. third valve, 23. third pipe, 24. fourth pipe, 25 . 4th valve, 26. 5th valve, 27. 6th valve, 28. 5th pipe, 29. 7th valve, 30. 6th pipe, 31. 7th pipe, 32. 8th valve, 33. . Nine valves, 34. Tenth valve, 35. Liquid _CO2 delivery branch, 36. Safety valve, 37. Eleventh valve, 38. Downhole mobile liquid _CO2 storage tank.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

The present invention provides a comprehensive prevention and control method for liquid CO ₂ in coal spontaneous combustion and gas disasters in coal mines. As shown in Figures 1-3, the optimal arrangement of the long-distance transportation system for liquid CO ₂ is determined according to the mine excavation project plan, ventilation system diagram and the comparison diagram of the upper and lower wells. method, the liquid CO ₂ can be led to the required fire-proof goaf (12) and the coal seam anti-permeability working surface through the transportation pipe network, and the liquid CO ₂ can also be led to other mining areas through the pipeline. The specific implementation is as follows. :

Step 1. Determine the layout of the liquid CO ₂ long-distance conveying system according to the mine excavation project plan, ventilation system diagram, and the upper and lower comparison diagrams of the mine, and ensure that the liquid CO ₂ conveying pipeline is in the return air tunnel: ① If the required mining area or working face The distance from the coal mine return air shaft 15 is relatively short, and the long-distance liquid CO ₂ conveying pipeline can be arranged in the return air shaft; ② If the required mining area or working face is far away from the mine return air shaft, pass the pipeline from the ground to the return air shaft. Shafts are required to complete the installation of liquid CO ₂ pipelines;

The liquid CO ₂ long-distance transportation system includes a liquid CO ₂ storage tank unit and a pipeline network. The liquid CO ₂ storage tank unit includes a liquid CO ₂ storage tank installation base 1, multiple liquid CO ₂ storage tanks 2, and a liquid CO 2 unit. ₂ booster pump 4, 1 air temperature liquid _CO2 vaporizer 5 and several pipes for connecting equipment.

Step 2. Construct the installation foundation of the liquid CO ₂ storage tank at the location of the shaft determined in Step 1 or the selected location of the return air wellhead, and install multiple liquid CO ₂ storage tanks and 1 liquid CO ₂ storage tank on the installation foundation of the liquid CO 2 storage tank. _CO2 booster pump and 1 air-temperature liquid _CO2 vaporizer, the gas phase outlets of the liquid _CO2 storage tanks of multiple liquid _CO2 storage tanks are all connected with the gas phase outlet of the liquid _CO2 booster pump through pipes; The liquid phase outlet of the liquid _CO2 storage tank is connected with the liquid phase inlet of the liquid _CO2 booster pump and the inlet of the air-temperature liquid _CO2 vaporizer through pipes _; the outlet of the liquid _CO2 booster pump and the The outlet of the air-temperature liquid CO ₂ vaporizer leads the liquid CO ₂ to the required position downhole through the conveying pipe network;

Step 3. In addition to leading the liquid CO ₂ to the required fire-proof goaf 12 and the coal seam anti-permeability working face through the pipeline network, the liquid CO ₂ can also be led to other mining areas through the pipeline;

Step 4. The conveying pipe network includes a duplex stainless steel liquid CO ₂ conveying pipeline 7 (ferrite and austenite each account for about 50%), a number of liquid CO ₂ conveying branch pipes 35, and the working face return air follows the tank for liquid CO _2. Displacement pipeline 8, goaf liquid _CO2 injection pipeline 9; several liquid _CO2 pipelines are connected with duplex stainless steel liquid _CO2 pipeline 7, and one liquid _CO2 pipeline is set in the mining area. In the coal working face return air lane 13, one side of the liquid CO ₂ conveying branch pipe is connected with several working face return air along the tank liquid CO ₂ displacement conveying pipe 8, and the other side of the liquid CO ₂ conveying branch pipe is connected There are several goaf liquid CO ₂ pressure injection pipelines 9; through several goaf liquid CO ₂ pressure injection pipelines 9 and several working face return air along the tank liquid CO ₂ displacement conveying pipe 8 to the working face and the The fire-proof goaf 12 is continuously and evenly injected with liquid CO ₂ ; the remaining liquid CO ₂ delivery branch pipes 35 are arranged in the surrounding roadways; the liquid CO ₂ delivery branch pipe 35 of the underground liquid CO ₂ supply substation is provided with a safety valve 36 and a first Eleven valve 37;

Step 5. Store a plurality of underground mobile liquid CO ₂ storage tanks 38 in the chamber 14 as underground liquid CO ₂ supply sub-stations. When other working faces or goafs in the mining area need liquid CO ₂ displacement or fire prevention, The liquid CO ₂ supply sub-station completes the filling of the mobile storage tank and transports it to the required injection position of the liquid CO ₂ through the existing transportation system of the mine.

A self-operated pressure regulating valve 16 is installed at the end of the liquid CO ₂ pressure injection pipeline 9 in the goaf required for fire prevention.

After setting the regulating valve, the pressure is greater than or equal to 0.8MPa to ensure that the _CO2 in the pressure injection pipe network is mainly carried out in the liquid phase.

The liquid CO ₂ storage tank 2 has a volume of 25 m ³ or 50 m ³ .

The number of liquid _CO2 storage tanks 2 is two.

The volume of the downhole mobile liquid CO ₂ storage tank 38 is 2.0 m ³ .

According to the actual needs of each mine, when the storage capacity of liquid CO ₂ 2 in the ground storage tank is less than 10m ³ , the liquid CO ₂ transport semi-trailer should be replenished in time, and the corresponding replenishment frequency and cycle should be determined.

Example

The main coal seam of a certain mine is a high-gas-prone coal seam, which has a main coal mine 10 and a coal mine auxiliary shaft 11, and the mining level 17 of the mine is shown in FIG. 1 . The thickness of the coal seam is large, and the fully mechanized top coal mining method is adopted. During the mining process, the gas gushing volume is large and the gas gushing is abnormal, and the coal loss in the _goaf after mining is large, and the coal spontaneous combustion threat is serious.

Step 1. Determine the layout of the liquid CO ₂ long-distance conveying system according to the mine excavation project plan, ventilation system diagram and the comparison diagram of the upper and lower wells of the mine: ① If the required mining area or working face is 15 minutes away from the coal mine return air shaft, the long-distance liquid CO The CO ₂ conveying pipeline can be arranged in the return air shaft; ② If the required mining area or working face is far away from the mine return air shaft, the liquid CO ₂ conveying pipeline can be completed by drilling a shaft from the ground to the required position installation;

The liquid CO ₂ long-distance transportation system includes a liquid CO ₂ storage tank unit and a pipeline network. The liquid CO ₂ storage tank unit includes a liquid CO ₂ storage tank installation base 1, two liquid CO ₂ storage tanks 2, and one liquid CO 2 ₂ booster pump 4, 1 air temperature liquid _CO2 vaporizer 5 and several pipes for connecting equipment.

Step 2. Select a suitable position for the shaft or the return air wellhead determined in step 1, construct the liquid _CO2 storage tank installation base 1, and install multiple liquid _CO2 storage tanks on the liquid _CO2 storage tank installation base 1 2. 1 set of liquid _CO2 booster pump 4 and 1 set of air temperature type liquid _CO2 gasifier 5, the liquid _CO2 storage tank gas phase outlet 3 of multiple liquid _CO2 storage tanks 2 pass through the first pipeline 18 and the first pipeline 18 respectively. The second pipeline 19 is connected with the gas phase outlet of the liquid _CO2 booster pump 4, the first pipeline 18 is provided with a first valve 20, the second pipeline 19 is provided with a third valve 21 and a third valve 22; two liquid _CO2 The liquid phase outlet 6 of the liquid _CO2 storage tank of the storage tank 2 is connected to the liquid phase outlet of the liquid _CO2 booster pump 4 through a third pipeline 23 and a fourth pipeline 24, respectively. The third pipeline 23 is provided with a fourth valve 25, The fourth pipe 24 is provided with a fifth valve 26 and a sixth valve 27; the third pipe 23 is also communicated with the inlet of the air-temperature liquid CO ₂ gasifier 5 through the fifth pipe 28, and the fifth pipe 28 is provided with a seventh valve. Valve 29; the outlet of the liquid CO ₂ booster pump 4 and the outlet of the air-temperature liquid CO ₂ vaporizer 5 both lead the liquid CO ₂ to the required position downhole through the conveying pipe network;

The transportation pipeline network includes a duplex stainless steel liquid CO ₂ transportation pipeline 7, a sixth pipeline 30 and a seventh pipeline 31. The sixth pipeline 30 is connected to the outlet of the air temperature liquid CO ₂ vaporizer 5; the seventh pipeline 31 is connected to the liquid CO 2 gasifier 5. The outlet of the _CO2 booster pump 4 is connected; the sixth pipeline 30 is provided with an eighth valve 32, the seventh pipeline 31 is provided with a ninth valve 33, and the duplex stainless steel liquid _CO2 delivery pipeline 7 is provided with a tenth valve 34; The sixth pipeline 30 and the seventh pipeline 31 are both communicated with one end of the duplex stainless steel liquid CO ₂ delivery pipeline 7; the other end of the duplex stainless steel liquid CO ₂ delivery pipeline 7 is communicated with several liquid CO ₂ delivery branch pipes;

Step 3. In addition to leading the liquid CO ₂ to the required fire-proof goaf 12 and the coal seam anti-permeability working face through the pipeline network, the liquid CO ₂ can also be led to other mining areas through the pipeline;

Step 4. The conveying pipe network includes a duplex stainless steel liquid CO ₂ conveying pipeline 7 (ferrite and austenite each account for about 50%), several liquid CO ₂ conveying branch pipes, and the working face return air flows along the tank for liquid CO ₂ Displacement pipeline 8, goaf liquid CO ₂ injection pipeline 9; several liquid CO ₂ delivery branches are all connected with duplex stainless steel liquid CO ₂ delivery pipeline 7, and one of the liquid CO ₂ delivery branches is set in the coal mining area In the working face return air lane 13, one side of the liquid CO ₂ conveying branch pipe is connected with a number of working face return air along the tank liquid CO ₂ displacement conveying pipe 8, and the other side of the liquid CO ₂ conveying branch pipe is connected with Several goaf liquid CO ₂ pressure injection pipelines 9; through several goaf liquid CO ₂ pressure injection pipelines 9 and several working face return air along the tank liquid CO ₂ displacement pipeline 8 to the working face and fire prevention. The goaf 12 is continuously and uniformly injected with liquid CO ₂ ; the remaining liquid CO ₂ conveying branch pipes are arranged in the surrounding roadways;

Step 5. Store a plurality of underground mobile liquid CO ₂ storage tanks 38 in the chamber 14 as underground liquid CO ₂ supply sub-stations. When other working faces or goafs in the mining area need liquid CO ₂ displacement or fire prevention, The liquid CO ₂ supply sub-station completes the filling of the mobile storage tank and transports it to the required injection position of the liquid CO ₂ through the existing transportation system of the mine.

A self-operated pressure regulating valve 16 is installed at the end of the liquid CO ₂ pressure injection pipeline 9 in the goaf required for fire prevention.

After setting the regulating valve, the pressure is greater than or equal to 0.8MPa to ensure that the _CO2 in the pressure injection pipe network is mainly carried out in the liquid phase.

The liquid CO ₂ storage tank 2 has a volume of 50 m ³ .

The number of liquid _CO2 storage tanks 2 is two.

The volume of the downhole mobile liquid CO ₂ storage tank 38 is 2.0 m ³ .

Claims (7)

1. Liquid CO for spontaneous combustion of coal and gas disaster in underground coal mine₂The comprehensive control mode is characterized in that the liquid CO is determined according to a mine excavation project plan, a ventilation system diagram and an underground map₂Long distance transportation system arrangement for transporting liquid CO₂Is led out of the fireproof goaf (12) and the coal seam permeability-increasing working surface through a conveying pipe network, and in addition, liquid CO can be led out through a pipeline₂Leading to other mining areas.

2. The liquid CO for spontaneous combustion of coal underground coal mine and gas disaster according to claim 1₂The comprehensive prevention and control mode is characterized by being implemented according to the following steps:

step 1, determining liquid CO according to a mine excavation engineering plan, a ventilation system diagram and an underground and aboveground comparison diagram ₂Long-distance conveying system arrangement mode: firstly, if the mining area or the working face to be mined is closer to the return air shaft (15) of the coal mine, long-distance liquid CO₂The conveying pipeline can be arranged in the air return vertical shaft; secondly, if the required mining area or the working face is far away from the mine return air vertical shaft, the liquid CO is finished by drilling a vertical shaft from the ground to the required position₂Installing a conveying pipeline;

step 2, constructing liquid CO at the well-determined shaft driving position or the air return wellhead selection position in the step 1₂The storage tank is provided with a base (1) for receiving liquid CO₂A plurality of liquid CO are arranged on the storage tank installation foundation (1)₂Storage tank (2) and 1 liquid CO₂A booster pump (4) and 1 air temperature type liquid CO₂A gasifier (5) for a plurality of liquid CO₂Liquid CO of the storage tank (2)₂The gas phase outlets (3) of the storage tanks are communicated with liquid CO through pipelines₂The gas phase outlet of the booster pump (4) is communicated; multiple liquid CO₂Liquid CO of the storage tank (2)₂The liquid phase inlets (6) of the storage tanks are communicated with liquid CO through pipelines₂Liquid phase outlet of booster pump (4) and air temperature type liquid CO₂The inlet of the gasifier (5) is communicated; liquid CO₂Outlet of booster pump (4) and air temperature type liquid CO₂The outlets of the gasifiers (5) are used for delivering liquid CO through a delivery pipe network₂Leading to a required position underground;

step 3 except that liquid CO is added ₂Is led to the outside of the required fireproof goaf (12) and the coal seam permeability-increasing working surface through a conveying pipe network, and in addition, liquid CO can be led out through a pipeline₂Leading to other mining areas;

step 4, the conveying pipe network comprises two-phase stainless steel liquid CO₂A conveying pipeline (7) and a plurality of liquid CO₂Liquid CO in conveying branch pipe and working face return air crossheading₂Liquid CO in displacement conveying pipe (8) and goaf₂A pressure injection line (9); several liquid CO₂The conveying branch pipes are all connected with the duplex stainless steel liquid CO₂The delivery lines (7) are communicated, and one of the liquid CO is₂The branch conveying pipe is arranged in a return airway (13) of the coal face, and the liquid CO is₂One side of the conveying branch pipe is connected with a plurality of working face return air crossheading liquid CO₂Displacement of the transport pipe (8), the liquid CO₂The other side of the conveying branch pipe is connected with a plurality of goaf liquid CO₂A pressure injection line (9); passing liquid CO through a plurality of goafs₂Pressure injection pipeline (9) and a plurality of working face return air crossheading liquid CO₂The displacement conveying pipe (8) continuously and uniformly injects liquid CO to the working surface and the fireproof goaf (12)₂(ii) a The rest of the liquid CO is discharged₂The conveying branch pipes are arranged in the peripheral roadway;

step 5. storing a plurality of underground mobile liquid CO in the chamber (14)₂Storage tank (38) as downhole liquid CO₂Supply to substations when other working faces or goafs in the mining area require liquid CO ₂In the case of displacement or fire protection, in liquid CO₂The supply substation completes filling of the mobile storage tank and transports the liquid CO to the existing transportation system of the mine₂The desired injection location.

3. Coal mine according to claim 2Liquid CO for underground coal spontaneous combustion and gas disaster₂A comprehensive prevention and control mode is characterized in that liquid CO is in a goaf required by fire prevention₂The tail end of the pressure injection pipeline (9) is provided with a self-operated pressure regulating valve (16).

4. The liquid CO for spontaneous combustion of coal underground coal mine and gas disaster according to claim 3₂The comprehensive control mode is characterized in that the pressure is more than or equal to 0.8MPa after the regulating valve is set, and CO in the pressure injection pipe network is ensured₂Mainly in the liquid phase.

5. The liquid CO for spontaneous combustion of coal underground coal mine and gas disaster according to claim 2₂An integrated control mode, characterized in that the liquid CO is₂The volume of the storage tank (2) is 25m³Or 50m³。

6. The liquid CO for spontaneous combustion of coal underground coal mine and gas disaster according to claim 2₂A comprehensive control mode, characterized in that liquid CO₂The number of the storage tanks (2) is two.

7. The liquid CO for spontaneous combustion of coal underground coal mine and gas disaster according to claim 2₂A comprehensive control mode, characterized in that the underground mobile liquid CO₂The volume of the storage tank (38) is 2.0m ³。

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