Coal mine goaf disaster control system

Abstract

The utility model belongs to the technical field of coal mine disaster prevention and control, and particularly relates to a coal mine goaf disaster control system which comprises a discharge unit, an extraction unit, a fire preventing and extinguishing unit and a control unit. The discharging unit comprises a discharging pipeline, one end of an inlet of the discharging pipeline penetrates through the closed wall to enter the goaf, one end of an outlet of the discharging pipeline is connected with a check valve and arranged in the return airway, the extraction unit comprises an extraction pipeline, and one end of the extraction pipeline is connected with the discharging pipeline through a three-way valve. The other end is sequentially connected with the filter pump, the filter compressor and the storage part; the fire preventing and extinguishing unit comprises a nitrogen injection pipeline, one end of the nitrogen injection pipeline is connected with the nitrogen supply component, and the other end penetrates through the closed wall and is inserted into the goaf; the control unit comprises a processing module and a gas detection assembly and is used for work conversion among the discharging unit, the extraction unit and the fire preventing and extinguishing unit. The device can be used for carrying out self-adaptive adjustment treatment on gas in various modes, and is high in safety performance and better in treatment effect.

Description

Technical Field

[0001] This utility model belongs to the field of coal mine disaster prevention and control technology, and specifically relates to a coal mine goaf disaster management system. Background Technology

[0002] Currently, most deep coal seams in my country exhibit "three highs and two lows" characteristics in their gas occurrence (three highs: high gas content, high plasticity, and high gas adsorption capacity; two lows: low permeability and low proportion of conventional fractures and fissures under enhanced ventilation measures). The low permeability of deep coal seams, in particular, makes conventional borehole pre-drainage of coal seam gas ineffective. This leads to gas accumulation in goafs due to the influx of residual coal and gas from adjacent layers, increasing the risk of safety accidents. While shallow coal seams are addressed by constructing permanent sealing walls to block gas in goafs and optimize ventilation systems, the large diurnal temperature range and high gas emission rates in goafs, coupled with the shallow burial depth, mean that without preventative gas release, excessive pressure within the goaf could lead to roof collapse and ground connection, causing the goaf to absorb oxygen and posing a fire hazard.

[0003] Currently, while various technical solutions have been adopted to prevent gas disasters in goaf areas, there are significant limitations in gas control for both deep and shallow coal seams, posing serious safety risks during coal mining. For example, the paper "Characteristics and Control Technology of 'Breathing' Phenomenon in Closed Goaf Areas of Low-Gas Mines" utilizes the fluctuation of external air pressure in the goaf to trigger a "breathing" phenomenon, employing gas release for goaf gas control. However, coal mine breathing is more pronounced in shallow coal seams but weaker in deep coal seams. In deep coal seam goaf areas, numerous uncertainties exist. Preventative gas release from the goaf may lead to roof collapse, connecting it to the surface and causing the goaf to absorb oxygen, posing a fire hazard. For example, Chinese patent CN108180033B discloses an automatic control device for gas release in a sealed goaf. This device utilizes the positive pressure difference inside and outside the sealed wall to open the control valve of the gas release pipeline, automatically releasing high-concentration gas from the sealed goaf. The valve opening is adjusted based on the gas concentration value monitored at the pipeline outlet. However, due to the complexity of actual site conditions, this solution has a long response time, especially when the wall leaks air, taking a considerable amount of time to become effective. Fresh air is drawn through the sealed wall, with some entering the interior, creating three zones of spontaneous combustion in the goaf of the coal mining face. These three zones can be divided into a heat dissipation zone, an oxidation zone, and an asphyxiation zone. Since the sealed wall and pipeline are not sealed, opening the gas release pipe draws in fresh air from the airflow into the goaf. Under these conditions, gas release exacerbates the inward movement of the oxidation zone and shortens the spontaneous combustion time. However, coal mines typically use exhaust ventilation, and the gas extraction pipelines often experience low negative pressure during extraction. If the coal seam is shallow, unprotected extraction of gas from the goaf could lead to roof collapse and connection to the surface, causing the goaf to absorb oxygen and posing a fire hazard. Furthermore, while this method can monitor spontaneous combustion in enclosed goafs, it cannot extinguish fires promptly after detection, resulting in insufficient disaster prevention and low safety assurance. For example, Chinese patent CN115522969A discloses an automatic control device for gas extraction and nitrogen injection pressure equalization in underground coal mine goafs. The design of the extraction and nitrogen injection pipelines involved in this scheme cannot penetrate deep into the goaf. The injected nitrogen is located on the side of the goaf's sealed wall and cannot be introduced into the goaf. The goaf is a large three-dimensional area formed during the working face mining process, and the gas in the goaf is extracted. As a result, the nitrogen injected on the side of the sealed wall may be directly discharged from the extraction pipeline, failing to prevent spontaneous combustion inside the goaf. Furthermore, the extraction pipeline may cause the return air gas to exceed the limit, leading to safety issues. Utility Model Content

[0004] To address the problems existing in the prior art, the purpose of this utility model is to provide a coal mine goaf disaster management system that can adaptively regulate and manage gas in the goaf in multiple ways, effectively improving the safety performance of the goaf and gas discharge, greatly achieving disaster prevention, and providing better management results.

[0005] The technical solution of this utility model is:

[0006] A coal mine goaf disaster management system includes a sealed wall and further includes:

[0007] The discharge unit includes a discharge pipeline and a check valve. The inlet end of the discharge pipeline passes through the sealed wall to connect with the goaf area, and the outlet end is connected with the return airway. The check valve is installed at the end of the discharge pipeline near the return airway.

[0008] A three-way valve is installed on the discharge pipeline to form an extraction outlet on the discharge pipeline;

[0009] The extraction unit includes an extraction pipeline, a filter pump, a gas filtration and compression component, and a storage component. One end of the extraction pipeline is connected to the extraction outlet, and the other end is connected to the inlet of the filter pump. The outlet of the filter pump is connected to the storage component through the gas filtration and compression component.

[0010] The fire prevention and extinguishing unit includes a nitrogen injection pipeline and a nitrogen supply component. One end of the nitrogen injection pipeline is connected to the nitrogen supply component, and the other end is used to pass through the sealed wall and insert into the goaf area.

[0011] The control unit includes a processing module and a gas detection component. The gas detection component is used to detect the methane concentration and spontaneous combustion indicator gas in the goaf. The processing module is used to control the opening and closing of the three-way valve according to the methane concentration and spontaneous combustion indicator gas parameters obtained by the detection module, so as to realize the operation switching between the emission unit, the extraction unit and the fire prevention and extinguishing unit.

[0012] Preferably, the gas detection component includes a multi-parameter sensor and a carbon monoxide sensor. The multi-parameter sensor is used to detect the methane concentration in the goaf, and the carbon monoxide sensor is used to detect the spontaneous combustion marker gas in the goaf.

[0013] Preferably, both the discharge pipeline and the nitrogen injection pipeline are provided with a sealing structure between themselves and the sealed wall.

[0014] Preferably, the sealed wall comprises:

[0015] One of the sealed walls is in contact with the goaf on one side;

[0016] Sealing wall 2 is parallel to sealing wall 1 and is located on the side of sealing wall 1 away from the goaf area, and a filling gap is provided between sealing wall 1 and sealing wall 2.

[0017] Filler material is used to fill the gaps.

[0018] Preferably, the filler material is a silicate-modified polyurethane material.

[0019] Preferably, an emission warning barrier is installed in the return air tunnel and on the side of the emission pipeline outlet, and a methane sensor is installed on the outside of the emission warning barrier.

[0020] Preferably, a U-shaped differential pressure gauge is also installed on the sealed wall to monitor the pressure difference between the goaf and the outside.

[0021] Preferably, the nitrogen injection pipeline includes a first nitrogen injection pipe branch, a second nitrogen injection pipe branch, a main nitrogen injection pipe branch, and nitrogen injection pipe interfaces. One end of the main nitrogen injection pipe branch is connected to the nitrogen supply component, and the other end extends through the sealed wall to the goaf. At least two nitrogen injection pipe interfaces are provided on the side wall of the goaf along the main nitrogen injection pipe branch. The two nitrogen injection pipe interfaces are respectively connected to the first nitrogen injection pipe branch and the second nitrogen injection pipe branch, and the first nitrogen injection pipe branch is close to the sealed wall.

[0022] Preferably, the main nitrogen injection pipe is located in an arc shape within the goaf, and the first and second branches of the nitrogen injection pipe are both located on the same side of the concave portion of the main nitrogen injection pipe. Furthermore, the outlet of the first branch of the nitrogen injection pipe is higher than that of the second branch of the nitrogen injection pipe, and a third branch of the nitrogen injection pipe is also provided on the convex portion of the main nitrogen injection pipe within the goaf.

[0023] Compared with the prior art, the coal mine goaf disaster management system of this utility model has the following beneficial effects:

[0024] During gas control, this device utilizes a detection module to accurately detect methane concentration and spontaneous combustion marker gases in the goaf, providing real-time feedback to the processing module. The processing module then determines the methane concentration and the presence or absence of spontaneous combustion marker gases, issuing corresponding commands to the three-way valve to achieve operational switching between the emission unit, extraction unit, and fire prevention unit. Specifically, when no spontaneous combustion marker gases are detected and the methane concentration is low, the emission unit operates by adjusting the three-way valve to connect the emission pipeline to the valve, closing the valve to the extraction pipeline, and releasing the gas through the check valve to the return airway for dissipation. When no spontaneous combustion marker gases are detected... When the methane concentration is high, the extraction unit operates by adjusting the three-way valve to connect it to the extraction pipeline and close the discharge pipeline to the three-way valve. The gas then passes through the extraction pipeline into the gas filtration and compression unit, where it is filtered to form liquid methane, which is collected in the storage unit for recycling. When a spontaneous combustion indicator gas is detected, the fire prevention and extinguishing unit operates by closing both the three-way valve to the extraction and discharge pipelines. The nitrogen supply unit is activated, injecting nitrogen into the goaf through the nitrogen injection pipeline to prevent spontaneous combustion of coal. Thus, this device can adaptively regulate and control the gas in the goaf through various methods, effectively improving the safety of the goaf and gas discharge, greatly enhancing disaster prevention, and achieving better control results. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of the system in an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the structure of the discharge pipeline in an embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of the nitrogen injection pipeline in an embodiment of the present invention;

[0028] Figure 4 This is a schematic diagram of the gas filtration and compression component in an embodiment of the present invention;

[0029] Figure 5 This is a schematic diagram of the gas cylinder control section in an embodiment of the present invention.

[0030] Explanation of reference numerals in the attached figures:

[0031] 1. Sealed structure; 2. Multi-parameter sensor; 3. Carbon monoxide sensor; 301. Alarm indicator light; 4. Extraction pipeline; 5. Filter pump; 6. Gas filtration and compression components; 601. CH4 filter; 602. CH4 airflow inlet; 603. Gas tank; 604. Pressure gauge one; 605. Pressure sensor; 606. Compressor; 7. Cryogenic flow meter one; 8. Extraction chamber; 9. Fixing frame; 10. Fixing chain; 12. Cryogenic pipeline; 13. Cryogenic valve; 14. CH4 pressure regulator; 15. Gas cylinder control section; 1501. Pressure gauge two; 1502. Pressure stabilizer; 16. Liquefied CH4 cylinder; 17. Return airway; 18. Methane sensor; 1801. 19. Discharge warning barrier; 20. Check valve; 21. Nitrogen generating chamber; 22. Discharge pipeline; 2101. Sealing ring; 2102. Sealing sleeve; 2103. Sealing bolt hole; 23. Nitrogen generator; 24. Nitrogen injection pressure-resistant valve; 25. Nitrogen injection pump; 26. Three-way valve; 27. Nitrogen injection pipeline; 28. Pressure gauge three; 29. ​​Pipeline connection; 20. First branch of nitrogen injection pipeline; 20. Second branch of nitrogen injection pipeline; 21. Main nitrogen injection pipeline; 22. Nitrogen injection pipeline interface; 23. Flow meter two; 24. Regulating valve; 25. Third branch of nitrogen injection pipeline; 26. Sealing wall two; 27. Filling material; 28. U-shaped differential pressure gauge; 29. ​​Goaf; 20. Sealing wall one. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0033] Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0034] Furthermore, the technical solutions of the various embodiments of this utility model can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0035] See Figures 1 to 5As shown, in order to adaptively regulate and control the gas in the goaf 30 in multiple ways, the safety performance of the goaf 30 and gas discharge is effectively improved, greatly realizing disaster prevention and control. This embodiment provides a coal mine goaf disaster control system, including a sealed wall, a discharge unit, a three-way valve 25, an extraction unit, a fire prevention and extinguishing unit, and a control unit. The discharge unit includes a discharge pipeline 21, a check valve 19, and a return airway 17. One end of the discharge pipeline 21 passes through the sealed wall and enters the goaf 30, and one end of the discharge pipeline 21 is placed in the return airway 17. The check valve 19 is installed at the end of the discharge pipeline 21 near the return airway 17. The three-way valve 25 is installed on the discharge pipeline 21 to form an extraction outlet on the discharge pipeline 21. Preferably, the three-way valve 25 is an electromagnetic three-way valve 25, which has good control effect and fast response speed. The extraction unit includes an extraction pipeline 4, a filter pump 5, a gas filtration and compression component 6, and a storage component. One end of the extraction pipeline 4 is connected to the extraction outlet, and the other end is connected to the inlet of the filter pump 5. The outlet of the filter pump 5 is connected to the storage component through the gas filtration and compression component 6. The fire prevention and extinguishing unit includes a nitrogen injection pipeline 26 and a nitrogen supply component. One end of the nitrogen injection pipeline 26 is connected to the nitrogen supply component, and the other end is used to pass through the sealed wall and insert into the goaf 30. The control unit includes a processing module and a gas detection component. The gas detection component is installed on the discharge pipeline 21 and is located between the three-way valve 25 and the sealed wall. The gas detection component is used to detect the methane concentration and spontaneous combustion indicator gas in the discharge pipeline 21. The processing module is used to control the opening and closing of the three-way valve 25 according to the methane concentration and spontaneous combustion indicator gas parameters obtained by the detection module, so as to realize the operation switching between the discharge unit, the extraction unit, and the fire prevention and extinguishing unit.

[0036] See Figure 1 As shown, to prevent gas leakage from the goaf 30, the sealed wall includes a first sealed wall 31, a second sealed wall 27, and filling material 28. For goaf 30 with an existing old sealed wall, the old sealed wall is used as the first sealed wall 31. The second sealed wall 27 is reinforced on the side of the first sealed wall 31 away from the goaf 30, and a filling gap is provided between the first sealed wall 31 and the second sealed wall 27. Filling material 28 is injected into the filling gap to improve the sealing effect. The filling material 28 should preferably be silicate-modified polyurethane (silicate-modified polyurethane is a high-performance flame-retardant material that is an organic-inorganic composite material, possessing the mechanical properties of polyurethane and the flame-retardant characteristics of inorganic materials. Silicate-modified polyurethane is currently mainly used for underground reinforcement in coal mines, providing high strength while having excellent flame retardancy to ensure the safety of coal mine production). At the same time, a U-shaped differential pressure gauge 29 is installed on the sealed wall. The U-shaped differential pressure gauge 29 contains a water column and is used to monitor the pressure difference between the inside and outside of the sealed wall.

[0037] See Figure 1As shown, furthermore, to prevent gas leakage from the goaf 30, when the discharge pipeline 21 and nitrogen injection pipeline 26 are installed, the portions of the discharge pipeline 21 and nitrogen injection pipeline 26 that pass through the sealing wall 1 31, the sealing wall 27, and the filling material 28 are sealed using a two-plug-one-injection sealing structure 1. Specifically, the two-plug-one-injection implementation method is as follows: using a grouting bag, a grouting pump, and mine-use sealing hole expansion cement. The grouting bag consists of an inner grouting bag, an outer grouting bag, a grouting pipe, and a return grouting pipe that are fixedly connected. The inner grouting bag and the outer grouting bag are fixedly connected by the grouting pipe. There is a burst valve on the grouting pipe near the inner grouting bag. The inner grouting bag is at the top of the grouting pipe, and the outer grouting bag is 1m to 2m away from the hole at the other end of the grouting pipe. One end of the return grouting pipe is between the inner grouting bag and the outer grouting bag, and the other end passes through the outer grouting bag. The discharge pipe 21 is passed sequentially through the inner and outer sluice bags. The grouting pipe and return grout pipe exit through the discharge pipe 21 and can be fixed to the discharge pipe 21 with a strip. The inner sluice bag is fixed to the end of the discharge pipe 21 near the goaf with a strip and extends into the borehole formed by the sealing wall 31, the filling material 28, and the sealing wall 27. The discharge pipe 21 carries the inner sluice bag into the borehole and is flush with the side of the 31 near the goaf. The outer sluice bag is located at the opening of the sealing wall 27 on the side away from the goaf, about 10cm to 20cm away from the goaf. The grouting pipe is connected to the grouting pump. The grout enters the grouting pipe due to the grouting pressure. Due to the action of the one-way valve, the grout enters the outer and inner bladders. The bladders expand rapidly, fastening the outer diameter of the bladders to the borehole wall and sealing the holes at both ends of the sealing device. When the pressure is greater than 2.0 MPa, the burst valve bursts, and the grout fills the middle part of the two bladders, thereby achieving multi-layer sealing. Gas is then discharged through the gas drainage pipeline connected to the gas drainage pipe.

[0038] See Figure 1As shown, furthermore, to facilitate the selection of different gas prevention methods and the switching of operations between the emission unit, extraction unit, and fire prevention and extinguishing unit, thereby improving the gas prevention effect, the gas detection component includes a multi-parameter sensor 2 and a carbon monoxide sensor 3. Both the multi-parameter sensor 2 and the carbon monoxide sensor 3 are installed on the emission pipeline 21, with the carbon monoxide sensor 3 positioned between the multi-parameter sensor 2 and the three-way valve 25. Both the multi-parameter sensor 2 and the carbon monoxide sensor 3 are electrically connected to the processing module. Thus, the multi-parameter sensor 2 can accurately measure and provide feedback on the methane concentration entering the emission pipeline 21, while the carbon monoxide sensor 3 can detect and provide feedback on the spontaneous combustion indicator gas (CO) immediately. The processing module generates extraction or gas injection displacement signals based on the methane concentration feedback. It also identifies the spontaneous combustion indicator gas (CO) information, enabling the processor to generate nitrogen injection and valve closure signals. The carbon monoxide sensor 3 is connected to an alarm indicator 301; when CO is detected, the alarm indicator 301 responds immediately, facilitating timely intervention by personnel. Furthermore, the processing module integrates various signals to achieve seamless operation switching between the emission unit, extraction unit, and fire prevention / extinguishing unit.

[0039] See Figure 1 As shown, to ensure the safety of the outlet of the discharge pipeline 21, the discharge unit is equipped with a discharge warning barrier 1801 located in the return airway 17 and on one side of the outlet of the discharge pipeline 21. The discharge warning barrier 1801 includes an upwind barrier and a downwind barrier. The upwind barrier is 5m away from the outlet of the discharge pipeline 21, and the downwind barrier is 30m away from the outlet of the discharge pipeline 21. A methane sensor 18 is installed within 1m to 2m outside the downwind barrier at the outlet of the discharge pipeline 21. When the discharge unit is discharging gas, the discharge pipeline 21 discharges the gas flow (return air) flowing out of the goaf 30 into the return airway 17. A discharge warning barrier 1801, i.e., an upwind barrier and a downwind barrier, must be installed at the outlet of the discharge pipeline 21, and warning signs must be hung. No work is allowed between the two barriers. During discharge, the methane sensor 18 is monitored to prevent the return air gas from exceeding the limit. See also Figure 2 As shown, the length of the discharge pipe 21 is designed with a multi-segment connection. The two adjacent discharge pipe segments 21 are completed by sealing rings 2101 and sealing sleeves 2102, and are reinforced with bolts and nuts through sealing bolt holes 2103. The discharge pipe adopts DN90mm×2.5mm steel wire skeleton pipe.

[0040] See Figure 1 and Figure 4As shown, in order to recover and utilize the extracted high-concentration gas, the extraction unit includes, in addition to the extraction pipeline 4, filter pump 5, gas filtration and compression component 6, and storage component, a cryogenic flow meter 7, extraction chamber 8, cryogenic pipeline 12, cryogenic valve 13, and CH4 pressure regulator 14. The filter pump 5, gas filtration and compression component 6, and storage component are all installed in the extraction chamber 8. The extraction pipeline 4 uses a DN90mm×2.5mm steel wire reinforced pipeline. The storage component includes a fixing frame 9, a fixing chain 10, a liquefied CH4 bottle 16, and a gas cylinder control section 15 located at the inlet section of the liquefied CH4 bottle 16. The liquefied CH4 bottle 16 is mounted on the fixing frame 9 using the fixing chain 10. The gas cylinder control section 15 consists of a pressure gauge 1501 and a pressure regulator 1502. The gas filtration and compression component 6 consists of a CH4 filter 601 (molecular sieve), a CH4 gas inlet 602, a gas tank 603, a pressure gauge 604, a pressure sensor 605, and a compressor 606. The filter pump 5 filters water, slag, and other impurities from the extraction pipeline 4, allowing only gas to be delivered to the gas filtration and compression component 6. The gas delivered to the gas filtration and compression component 6 first passes through the CH4 filter 601 (molecular sieve) to separate CH4 gas, and then flows into the gas tank 603 from the CH4 gas inlet 602. After adjusting the internal pressure of the gas tank 603, the compressor 606 compresses the CH4 gas into liquid methane. The liquid methane then passes sequentially through the pressure sensor 605 (which displays the pressure of the liquid methane discharged from the outlet of the gas filtration and compression component 6; it is a cryogenic pressure sensor 605), a cryogenic flow meter 7, and then through the cryogenic pipeline 12. The cryogenic valve 13 and CH4 regulator 14 (CH4 regulator 14 can withstand cryogenic temperatures and ensures that the methane gas volatilized in the gas cylinder will not affect the pipeline, thus maintaining stable downstream pressure) enter the liquefied CH4 bottle 16 after passing through the gas cylinder control section 15. There are multiple liquefied CH4 bottles 16. When one of the liquefied CH4 bottles 16 is full, the control section and cryogenic valve 13 of this liquefied CH4 bottle 16 are closed, the compression power of the filter pump 5 is reduced, the cryogenic pipeline 12 is connected to the gas cylinder control section 15 of the next liquefied CH4 bottle 16 and opened, the cryogenic valve 13 is opened and the power of the filter pump 5 is restored to continue collecting liquid methane.

[0041] See Figure 1 and Figure 3As shown, furthermore, in order to efficiently extinguish a fire after a natural disaster is detected in the goaf 30, the nitrogen supply component in the fire prevention and extinguishing unit consists of a nitrogen injection pump 24, a nitrogen injection pressure-resistant valve 23, a nitrogen generator 22, and a nitrogen generation chamber 20. Both the nitrogen injection pump 24 and the nitrogen generator 22 are located in the nitrogen generation chamber 20. The outlet of the nitrogen generator 22 is connected to the nitrogen injection pump 24, and the outlet of the nitrogen injection pump 24 is connected to the nitrogen injection pipeline 26. A nitrogen injection pressure-resistant valve 23 is installed on the connecting pipeline between the nitrogen generator 22 and the nitrogen injection pump 24. The nitrogen injection pipeline 26 uses a multi-segment connection for easy length adjustment. Adjacent nitrogen injection pipelines 26 are connected by a pipe connector 2602. The nitrogen injection pipeline 26 includes a first branch 2603, a second branch 2604, a main branch 2605, and a nitrogen injection interface 2606. One end of the main nitrogen injection pipe 2605 is connected to the nitrogen supply component, and the other end extends through the sealed wall to the goaf 30. The main nitrogen injection pipe 2605 is also equipped with a pressure gauge 2601, a flow meter 2607, and a regulating valve 2608. The pressure gauge 2604 indicates the pressure of the injected nitrogen, the flow meter 2607 indicates the amount of injected nitrogen, and the regulating valve 2608 adjusts the pressure and flow rate of the injected nitrogen. Furthermore, at least two nitrogen injection pipe interfaces 2606 are located on the side wall of the goaf 30, and these interfaces are connected to the first branch of the nitrogen injection pipe 2603 and the second branch of the nitrogen injection pipe 2604, respectively. The first branch of the nitrogen injection pipe 2603 is located close to the sealed wall. In addition, the main nitrogen injection pipe 2605 is located in an arc shape in the goaf 30, and the first branch pipe 2603 and the second branch pipe 2604 are both located on the same side of the concave part of the main nitrogen injection pipe 2605. Furthermore, the outlet of the first branch pipe 2603 is higher than that of the second branch pipe 2604. To ensure sufficient nitrogen distribution in the goaf, a third branch pipe 2609 is also provided, connected to the convex part of the main nitrogen injection pipe 2605 located in the goaf. Thus, through the coordination and distribution of the main nitrogen injection pipe 2605, the first branch pipe 2603, the second branch pipe 2604, and the third branch pipe 2609, nitrogen can be injected into different depths in the goaf 30, ensuring sufficient nitrogen distribution and preventing spontaneous combustion of coal.

[0042] The intelligent gas control device for the sealed wall disaster in the coal mine goaf, as described above, is used in the gas control process, including the following steps:

[0043] The gas entering the emission pipeline 21 from the goaf 30 is detected by the gas detection component, and the methane concentration and spontaneous combustion indicator parameters in the gas are obtained and fed back to the processing module.

[0044] The operation selection of the emission unit, extraction unit, and fire prevention and extinguishing unit is as follows: When no spontaneous combustion indicator gas is detected and the methane concentration is less than the preset value in the treatment module, the three-way valve 25 is adjusted to connect the emission pipeline 21 to the three-way valve 25, and the three-way valve 25 is closed to the extraction pipeline 4, thus activating the emission unit. The emission pipeline 21 discharges the gas to the return airway 17 for dissipation via the check valve 19. When no spontaneous combustion indicator gas is detected and the methane concentration is greater than the preset value in the treatment module... The preset value is adjusted to connect the three-way valve 25 to the extraction pipeline 4 and close the discharge pipeline 21 to the three-way valve 25, so that the extraction unit can work. The gas enters the gas filtration and compression component 6 through the extraction pipeline 4 and is filtered to form liquid methane, which is collected in the storage component. When the gas that is a sign of spontaneous combustion is detected, the three-way valve 25 is closed to both the extraction pipeline 4 and the discharge pipeline 21. The nitrogen supply component is started and nitrogen is injected into the goaf 30 through the nitrogen injection pipeline 26 to prevent coal spontaneous combustion.

[0045] Specifically, the design and application methods of the system are explained in detail below:

[0046] In the initial design phase, a portion of the nitrogen injection pipeline 26 and the discharge pipeline 21 were pre-embedded in the goaf 30 during its formation. Upon discovering abnormal gas levels in the sealed wall, gas concentration tests were conducted, and leak detection was performed. Foaming water was sprayed around the sealed wall; bubbles would form at the leak locations, which were then marked and sealed with grout. If the leakage was severe, numerous, and involved a large internal and external pressure difference, a flow-limiting and pressure-limiting method was first used to discharge high-concentration gas from the sealed wall. Once the pressure dropped to a certain differential, the sealed wall was then sealed. The overall principle of flow-limiting was to restrict the discharge flow rate to prevent excessive gas levels on the return air side. The overall principle of pressure-limiting was to limit the pressure difference (the pressure inside the sealed wall was always greater than the pressure outside, with a pressure difference of no less than 10 mmH2O; to prevent airflow through the sealed wall, the internal pressure was higher than the external pressure, allowing some of the seeping gas to be diluted and carried away by the airflow), preventing excessive oxygen intake that could lead to spontaneous combustion in the goaf 30. If the sealing is not ideal, a new sealing wall (sealing wall 27) is added in front of the old sealing wall (sealing wall 1 31), and the space between sealing wall 1 31 and sealing wall 2 27 is filled and sealed with silicate modified polyurethane material.

[0047] For gas emission: The gas emission pipe is connected to the pre-reserved access hole in the sealed wall. Gas enters the emission pipe 21 from the goaf 30 and passes through the multi-parameter sensor 2. The multi-parameter sensor 2 detects that the methane concentration in the pipe is too low, and the processing module does not send a sampling signal. At this time, the three-way valve 25 is connected to the emission pipe 21. After passing through the carbon monoxide sensor 3, no spontaneous combustion indicator gas is detected, and the processing module does not send a valve closing signal. Then, the gas flows through the emission pipe 21 to the check valve 19 and exits as return air from the return airway 17. When the emitted gas is discharged into the return airway 17 and forms a return airflow, an emission warning barrier 1801 must be installed at the outlet of the emission pipe 21.

[0048] For gas extraction: Gas enters the discharge pipeline 21 from the goaf 30 and passes through the multi-parameter sensor 2. The multi-parameter sensor 2 detects that the methane concentration in the pipeline reaches 30% or higher. The processing module generates a feedback extraction signal, connecting the three-way valve 25 to the extraction pipeline 4. After passing through the carbon monoxide sensor 3, no spontaneous combustion indicator gas is detected, and no valve closure signal is issued. The gas flows to the extraction pipeline 4 and passes through the filter pump 5 (a combination of a water ring vacuum pump and a filter device) to filter water, slag, and other impurities. The gas then passes through the CH4 filter 601 (molecular sieve) and enters the gas tank 603 of the gas filter and compression component 6 as CH4 gas from the CH4 gas flow inlet 602. It is then compressed into liquid methane by the compressor 606. The liquid methane passes through the pressure sensor 605 (the pressure sensor 605 indicates that the liquid methane has passed through the gas filter and compression component). The pressure discharged from outlet 6, which is a cryogenic pressure sensor 605 and a cryogenic flow meter 7, is transmitted through cryogenic pipeline 12, cryogenic valve 13, and CH4 pressure regulator 14 (CH4 pressure regulator 14 can withstand cryogenic temperatures and ensures that the methane gas volatilized in the gas cylinder will not affect the pipeline, thus maintaining stable downstream pressure). After passing through the gas cylinder control section 15, it enters the liquefied CH4 bottle 16. There are multiple liquefied CH4 bottles 16. When one of the liquefied CH4 bottles 16 is full, the control section and cryogenic valve 13 of this liquefied CH4 bottle 16 are closed, the compression power of the filter pump 5 is reduced, the cryogenic pipeline 12 is connected to the gas cylinder control section 15 of the next liquefied CH4 bottle 16 and opened, the cryogenic valve 13 is opened and the power of the filter pump 5 is restored to continue collecting liquid methane. When the multi-parameter sensor 2 detects that the methane concentration in the pipeline is gradually decreasing from 30%, the processing module sends back a gas injection displacement signal. At this time, the nitrogen injection pump 24 starts to run, and nitrogen is injected into the goaf 30 by the nitrogen generator 22 through the nitrogen injection pipeline 26, displacing the methane and entering the extraction pipeline.

[0049] For fire prevention and extinguishing: Gas enters the discharge pipeline 21 from the goaf 30. After passing through the multi-parameter sensor 2 and the carbon monoxide sensor 3, it is detected as a sign of spontaneous combustion. At this time, the processing module sends a valve closing signal to close the three-way valve 25. At the same time, the processing module sends a nitrogen injection fire prevention and extinguishing signal, and the nitrogen injection pump 24 starts to run. Nitrogen gas is generated by the nitrogen generator 22, passes through the nitrogen injection pressure valve 23, and is pumped by the nitrogen injection pump 24 from the nitrogen injection pipeline 26 through the regulating valve 2608 (controlling the injection pressure and flow rate), the pressure gauge (injection pressure), and the flow meter 2607 (injected nitrogen volume). Then, it enters the first branch of the nitrogen injection pipeline 2603 and the second branch of the nitrogen injection pipeline 2604 through the nitrogen injection pipeline interface 2606 via the main nitrogen injection pipeline 2605, injecting nitrogen gas into different depths in the goaf 30 to prevent coal spontaneous combustion.

[0050] In summary, the design of this system enables tiered and phased disaster management through the rational selection of disaster mitigation methods, resulting in reasonable cost and time savings. It reduces management and on-site costs, prevents mine shutdowns due to goaf hazard issues, and thus improves mine production efficiency. Furthermore, the system considers the potential associated disasters during the goaf hazard mitigation process for coordinated prevention and control, making it more comprehensive and scientific, avoiding blind construction and repetitive work, and improving mitigation efficiency.

[0051] Obviously, those skilled in the art can make various modifications and variations to this utility model without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this utility model and their equivalents, this utility model also intends to include these modifications and variations.

Claims

1. A coal mine goaf disaster management system, comprising a sealed wall, characterized in that, Also includes: The discharge unit includes a discharge pipeline (21) and a check valve (19). The inlet end of the discharge pipeline (21) passes through the sealed wall to connect with the goaf (30), and the outlet end is connected with the return airway (17). The check valve (19) is installed at one end of the discharge pipeline (21) near the return airway (17). A three-way valve (25) is installed on the discharge pipeline (21) to form an extraction outlet on the discharge pipeline (21); The extraction unit includes an extraction pipeline (4), a filter pump (5), a gas filtration and compression component (6), and a storage component. One end of the extraction pipeline (4) is connected to the extraction outlet, and the other end is connected to the inlet of the filter pump (5). The outlet of the filter pump (5) is connected to the storage component through the gas filtration and compression component (6). The fire prevention and extinguishing unit includes a nitrogen injection pipeline (26) and a nitrogen supply component. One end of the nitrogen injection pipeline (26) is connected to the nitrogen supply component, and the other end is used to pass through the sealed wall and insert into the goaf (30). The control unit includes a processing module and a gas detection component. The gas detection component is used to detect the methane concentration and spontaneous combustion indicator gas in the goaf (30). The processing module is used to control the opening and closing of the three-way valve (25) according to the methane concentration and spontaneous combustion indicator gas parameters obtained by the detection module, so as to realize the work conversion between the emission unit, the extraction unit and the fire prevention and extinguishing unit.

2. The coal mine goaf disaster management system according to claim 1, characterized in that, The gas detection component includes a multi-parameter sensor (2) and a carbon monoxide sensor (3). The multi-parameter sensor (2) is used to detect the methane concentration in the goaf (30), and the carbon monoxide sensor (3) is used to detect the spontaneous combustion indicator gas in the goaf (30).

3. The coal mine goaf disaster management system according to claim 1, characterized in that, Both the discharge pipeline (21) and the nitrogen injection pipeline (26) are provided with a sealing structure (1) between themselves and the sealed wall.

4. The coal mine goaf disaster management system according to claim 1, characterized in that, The sealed wall includes: Sealed wall 1 (31), one side of which is in contact with the goaf (30); Sealing wall 2 (27) is parallel to sealing wall 1 (31) and is located on the side of sealing wall 1 (31) away from the goaf (30), and a filling gap is provided between sealing wall 1 (31) and sealing wall 2 (27); Filler material (28) is used to fill the gap.

5. A coal mine goaf disaster management system according to claim 4, characterized in that, The filler material (28) is a silicate-modified polyurethane material.

6. A coal mine goaf disaster management system according to claim 1, characterized in that, An emission warning barrier (1801) is installed inside the return airway (17) and on the side of the outlet of the emission pipeline (21). A methane sensor (18) is installed outside the emission warning barrier (1801).

7. A coal mine goaf disaster management system according to claim 1, characterized in that, A U-shaped differential pressure gauge (29) is also installed on the sealed wall to monitor the pressure difference between the goaf (30) and the outside.

8. A coal mine goaf disaster management system according to claim 1, characterized in that, The nitrogen injection pipeline (26) includes a first branch of nitrogen injection (2603), a second branch of nitrogen injection (2604), a main nitrogen injection pipeline (2605), and nitrogen injection pipe interfaces (2606). One end of the main nitrogen injection pipeline (2605) is connected to the nitrogen supply component, and the other end extends through the sealed wall to the goaf (30). At least two nitrogen injection pipe interfaces (2606) are provided on the side wall of the goaf (30) of the main nitrogen injection pipeline (2605). The two nitrogen injection pipe interfaces (2606) are respectively connected to the first branch of nitrogen injection (2603) and the second branch of nitrogen injection (2604), and the first branch of nitrogen injection (2603) is close to the sealed wall.

9. A coal mine goaf disaster management system according to claim 8, characterized in that, The main nitrogen injection pipe (2605) is located in the goaf (30) and is arranged in an arc shape. The first branch (2603) and the second branch (2604) of the nitrogen injection pipe are both located on the same side of the concave part of the main nitrogen injection pipe (2605). The outlet of the first branch (2603) of the nitrogen injection pipe is higher than that of the second branch (2604). The convex part of the main nitrogen injection pipe (2605) located in the goaf (30) is also provided with a third branch (2609) of the nitrogen injection pipe.

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