A method for early warning and prevention of spontaneous combustion of coal in goaf area under gob-side entry-retaining mining method

Abstract

This invention discloses a method for early warning and prevention of spontaneous combustion of coal in goaf areas under the goaf-keeping mining method, belonging to the category of coal mine disaster prevention methods. The invention consists of two parts: a fire monitoring and early warning system and a fire prevention system. During the working face mining, a flexible membrane wall made of high-moisture material is used to support the roof on one side of the goaf-keeping roadway. Fire-prevention and extinguishing sleeves are arranged every 10-15 meters in a direction perpendicular to the axis of the transport roadway and track roadway. Temperature sensors and CO gas concentration sensors in the fire-prevention and extinguishing sleeves monitor the spontaneous combustion of coal in the goaf area and transmit the signals to the control terminal. When oxidation and heating or spontaneous combustion of residual coal in the goaf is detected, the fire prevention system is activated. Nitrogen generated by a nitrogen generator is precisely delivered to the coal spontaneous combustion danger area through nitrogen delivery pipelines and nitrogen injection holes on nitrogen injection pipelines to extinguish the fire. This method employs an intelligent nitrogen injection system that can precisely deliver nitrogen based on the specific location of the coal spontaneous combustion hazard, thereby improving fire extinguishing efficiency. It solves the problem that existing technologies are not easy to accurately monitor and extinguish fires in goaf areas. At the same time, precise nitrogen delivery and automated control reduce resource waste and energy consumption, which is in line with the development concept of green mines.

Description

Technical Field

[0001] This invention relates to the field of coal mine safety technology, specifically to a method for early warning and prevention of spontaneous combustion of coal in goaf under the goaf mining method of leaving the roadway open. Background Technology

[0002] Spontaneous combustion of residual coal in goaf areas is one of the major disasters in coal mines. The flammable and explosive gases such as CO and methane released by spontaneous combustion mix with underground air, easily triggering gas explosions and roof collapses, directly endangering the safety of personnel and facilities underground. Spontaneous combustion of residual coal leads to the ineffective oxidation of coal resources, with an average annual loss of over 10,000 tons in a single goaf area. Furthermore, the treatment of fire zones requires grouting, sealing, or even production shutdowns, significantly restricting coal mine production capacity. At the same time, the toxic pollutants released by spontaneous combustion cause lasting damage to the ecology of the mining area and its surroundings.

[0003] Currently, the main methods for early warning of spontaneous combustion of coal in goaf areas include bundled tube monitoring and temperature measurement using equipment such as optical fibers, but both have significant performance defects. Bundled tube monitoring relies on manual intermittent sampling, which takes too long for gas to diffuse from the spontaneous combustion point to the sampling port, making it difficult to promptly capture abnormal CO gas concentrations during the critical coal temperature stage. Furthermore, it has monitoring blind spots and is greatly affected by ventilation disturbances within the roadway. While optical fiber temperature measurement can acquire temperature field data, it cannot simultaneously analyze gas parameters such as CO and O2. Additionally, optical fibers are easily damaged, have high maintenance costs, and have low resolution, making it difficult to identify hidden fire sources. The shortcomings of these two early warning methods in terms of multi-parameter coordination, real-time performance, and anti-interference capabilities severely limit the accuracy of early warning in complex goaf environments. Therefore, a comprehensive early warning and prevention method is urgently needed to improve the effectiveness of spontaneous combustion prevention and control in goaf areas. Summary of the Invention

[0004] To address the aforementioned shortcomings, this invention provides a method for early warning and prevention of spontaneous combustion of coal in goaf areas under the goaf-keeping mining method, enabling early warning and precise prevention of spontaneous combustion of residual coal in goaf areas.

[0005] A method for early warning and prevention of spontaneous combustion of coal in goaf under the goaf-keeping mining method includes two parts: a fire monitoring and early warning system and a fire prevention system. The fire monitoring and early warning system includes a fire extinguishing sleeve, a temperature sensor, a CO gas concentration sensor, and a control terminal. The fire prevention system includes a nitrogen generator, a nitrogen delivery pipeline, a nitrogen injection pipeline, and a flange.

[0006] The fireproof sleeve is used to protect the internal nitrogen injection pipeline from being crushed and blocked; the fireproof sleeve extends 10-20cm through the flexible membrane wall into the goaf-side roadway, and a flange is installed at the extended end; the flange is fixed to the fireproof sleeve with bolts; several temperature sensors and CO gas concentration sensors are installed on the inner wall of the fireproof sleeve, and a ring of small ventilation holes is provided around the temperature sensors and CO gas concentration sensors on the surface of the fireproof sleeve to facilitate the detection of gas composition and temperature in the goaf area.

[0007] The temperature sensor is used to sense the temperature of the goaf area and transmit the data to the control terminal through a signal transmission line; the CO gas concentration sensor is used to detect the CO gas concentration and transmit the data to the control terminal through a signal transmission line; the control terminal is used to determine whether the data collected by the temperature sensor and the CO gas concentration sensor exceed the safety limit, and to activate the fire prevention system when the safety limit is exceeded.

[0008] The nitrogen delivery pipeline is made of a non-thermal-conducting material; the other end of the nitrogen delivery pipeline is connected to the nitrogen generator; the nitrogen injection pipeline extends from the hole in the middle of the flange and is connected to the nitrogen delivery pipeline; a valve is installed at the connection between the nitrogen delivery pipeline and the nitrogen injection pipeline; the opening and closing of the valve is controlled by a control terminal via radio signals.

[0009] The nitrogen injection pipe has several nitrogen injection holes evenly distributed radially; the nitrogen injection holes are covered by shape memory metal sheets; the shape memory metal sheets completely cover the nitrogen injection holes at room temperature, but will deform when the temperature exceeds the limit, causing the nitrogen injection holes to open.

[0010] An aviation plug is provided on the flange; the base of the aviation plug is connected to a temperature sensor and a CO gas concentration sensor via a signal transmission line; the free end of the aviation plug is connected to a control terminal via a signal transmission line.

[0011] The method for early warning and prevention of spontaneous combustion of coal in goaf under the goaf retention mining method is characterized in that, during the mining of the coal seam working face, a flexible membrane wall made of high water content material is used to support the roof on one side of the goaf retention roadway; and fire prevention and extinguishing sleeves are arranged in the goaf area every 10-15m of advance of the working face in a direction perpendicular to the axis of the transport roadway and the track roadway.

[0012] The method for early warning and prevention of spontaneous combustion of coal in goaf under the goaf-keeping mining method is characterized by the application of the above-mentioned device and includes the following implementation steps:

[0013] a. During the advance of the coal seam working face, when the coal in the goaf undergoes oxidation and heating or spontaneous combustion, the temperature sensor and CO gas concentration sensor in the corresponding area will sense the changes in temperature and CO gas concentration, respectively, and transmit the abnormal signal to the control terminal through the signal transmission line.

[0014] b. After receiving an abnormal signal, the control terminal controls the nitrogen generator to start producing nitrogen and simultaneously uses radio signals to remotely open the valves at the connection points of the nitrogen delivery pipeline and nitrogen injection pipeline in the corresponding area.

[0015] c. When the temperature exceeds the limit of the shape memory metal sheet at the nitrogen injection hole on the nitrogen injection pipeline, the shape memory metal sheet in the corresponding area deforms, and the nitrogen injection hole opens;

[0016] d. The nitrogen generated by the nitrogen generator enters the goaf through the nitrogen delivery pipeline and the nitrogen injection pipeline, and is sprayed out at the nitrogen injection holes opened on the nitrogen injection pipeline, accurately reaching the abnormal area to extinguish the fire;

[0017] e. When the temperature and CO gas concentration displayed on the control terminal return to normal, turn off the nitrogen generator and valve, the shape memory metal sheet returns to its original state, reseal the nitrogen injection hole, and the fire extinguishing is complete;

[0018] f. If the coal remaining in other parts of the goaf undergoes oxidation and heating or spontaneous combustion, then the early warning and fire extinguishing work shall be reimplemented in accordance with steps a to e.

[0019] The beneficial effects of this invention are:

[0020] ① By combining real-time monitoring with temperature and CO gas sensors, the accuracy and response speed of coal spontaneous combustion early warning are significantly improved, enabling timely warnings in the early stages of a fire and preventing its spread. ② Compared with traditional goaf fire prevention and extinguishing methods, this invention can cover the entire goaf area and precisely deliver nitrogen according to the specific location of the fire hazard, improving extinguishing efficiency and solving the problem of existing technologies making it difficult to extinguish goaf fires. ③ Precise nitrogen delivery and automated control reduce resource waste and energy consumption, aligning with the development concept of green mines. Attached Figure Description

[0021] Figure 1 This is an overall effect diagram of a method for early warning and prevention of spontaneous combustion of coal in goaf under a goaf-keeping mining method.

[0022] Figure 2 This is an overall rendering of the external fire protection sleeve.

[0023] Figure 3 This is an overall rendering of the internal nitrogen injection pipeline.

[0024] Figure 4 Front view of the flange connecting the external fire protection sleeve and the internal nitrogen injection pipe.

[0025] Figure 5 This is a cross-sectional view showing the connection between the external fire protection sleeve and the internal nitrogen injection pipeline via a flange.

[0026] Figure 6 This is an overall view of the memory metal sheet in its closed state.

[0027] Figure 7 This is an overall view of the shape memory metal sheet when it is heated and opened.

[0028] Figure 8 This is a flowchart of the system response when spontaneous combustion of coal occurs.

[0029] In the diagram, 1-Transport roadway; 2-Track roadway; 3-Working face; 4-Coal seam; 5-Flexible membrane wall; 6-Goaf; 7-Goaf-side roadway; 8-Control terminal; 9-Nitrogen generator; 10-Flange; 11-Bolt; 12-Aviation plug base; 13-Free end of aviation plug; 14-Signal transmission line; 15-Fireproof sleeve; 16-Ventilation hole; 17-Temperature sensor; 18-CO gas sensor; 19-Nitrogen delivery pipeline; 20-Nitrogen injection pipeline; 21-Valve; 22-Nitrogen injection hole; 23-Shape metal sheet. Detailed Implementation

[0030] The present invention will be further described below with reference to the embodiments and accompanying drawings:

[0031] like Figure 1-8 As shown, a method for early warning and prevention of spontaneous combustion of coal in goaf under the goaf-keeping mining method includes two parts: a fire monitoring and early warning system and a fire prevention system. The fire monitoring and early warning system includes a fire extinguishing sleeve (15), a temperature sensor (17), a CO gas concentration sensor (18), and a control terminal (8). The fire prevention system includes a nitrogen generator (9), a nitrogen conveying pipeline (19), a nitrogen injection pipeline (20), and a flange (10).

[0032] The fireproof sleeve (15) is used to protect the internal nitrogen injection pipe (20) from being crushed and blocked; the fireproof sleeve (15) extends 10-20cm through the flexible membrane wall (5) into the goaf-side roadway (7), and a flange (10) is installed at the extended end; the flange (10) is fixed to the fireproof sleeve (15) by bolts (11); several temperature sensors (17) and CO gas concentration sensors (18) are installed on the inner wall of the fireproof sleeve (15), and a ring of small ventilation holes (16) is provided around the temperature sensors (17) and CO gas concentration sensors (18) on the surface of the fireproof sleeve (15) to facilitate the detection of gas composition and temperature in the goaf area (6);

[0033] The temperature sensor (17) is used to sense the temperature of the goaf (6) and transmit the data to the control terminal (8) through the signal transmission line (14); the CO gas concentration sensor (18) is used to detect the CO gas concentration and transmit the data to the control terminal (8) through the signal transmission line (14); the control terminal (8) is used to determine whether the data collected by the temperature sensor (17) and the CO gas concentration sensor (18) exceed the safety limit, and to start the fire prevention system when the safety limit is exceeded.

[0034] The nitrogen delivery pipeline (19) is made of a non-thermal-conducting material; the other end of the nitrogen delivery pipeline (19) is connected to the nitrogen generator (9); the nitrogen injection pipeline (20) extends from the hole in the middle of the flange (10) and is connected to the nitrogen delivery pipeline (19); a valve (21) is provided at the connection between the nitrogen delivery pipeline (19) and the nitrogen injection pipeline (20); the opening and closing of the valve (21) is controlled by the control terminal (8) via radio signals;

[0035] The nitrogen injection pipe (20) has a plurality of nitrogen injection holes (22) evenly opened radially; the nitrogen injection holes (22) are covered by a memory metal sheet (23); the memory metal sheet (23) completely covers the nitrogen injection holes (22) at room temperature, but will deform when the temperature exceeds the limit, causing the nitrogen injection holes (22) to open.

[0036] An aviation plug is provided on the flange (10); the aviation plug base (12) is connected to the temperature sensor (17) and the CO gas concentration sensor (18) through the signal transmission line (14), and the free end (13) of the aviation plug is connected to the control terminal (8) through the signal transmission line (14).

[0037] During the mining of the coal seam (4) working face (3), a flexible membrane wall (5) made of high water content material is used to support the roof on one side of the goaf roadway (7); every 10-15m advance of the working face (3), fire-prevention and extinguishing sleeves (15) are arranged in the goaf area (6) in a direction perpendicular to the axis of the transport roadway (1) and the track roadway (2).

[0038] A method for early warning and prevention of spontaneous combustion of coal in goaf under the goaf-keeping mining method, characterized by the application of the above-mentioned device and including the following implementation steps:

[0039] a. During the advance of the coal seam (4) working face (3), when the coal in the goaf (6) undergoes oxidation and heating or spontaneous combustion, the temperature sensor (17) and CO gas concentration sensor (18) of the corresponding area sense the changes in temperature and CO gas concentration, respectively, and transmit the abnormal signal to the control terminal (8) through the signal transmission line (14).

[0040] b. After receiving an abnormal signal, the control terminal (8) controls the nitrogen generator (9) to start and begin producing nitrogen. At the same time, it uses radio signals to remotely open the valve (21) at the connection between the nitrogen delivery pipeline (19) and the nitrogen injection pipeline (20) in the corresponding area.

[0041] c. When the temperature exceeds the limit of the shape memory metal sheet (23) at the nitrogen injection hole (22) on the nitrogen injection pipe (20), the shape memory metal sheet (23) in the corresponding area deforms and the nitrogen injection hole (22) opens.

[0042] d. The nitrogen generated by the nitrogen generator (9) enters the goaf (6) through the nitrogen delivery pipeline (19) and the nitrogen injection pipeline (20), and is sprayed out at the nitrogen injection hole (22) opened on the nitrogen injection pipeline (20) to accurately reach the abnormal area and extinguish the fire.

[0043] e. When the temperature and CO gas concentration displayed on the control terminal (8) return to normal, turn off the nitrogen generator (9) and valve (21), the shape memory metal sheet (23) returns to its original state, and reseals the nitrogen injection hole (22), and the fire extinguishing is completed;

[0044] f. If the coal in other parts of the goaf (6) undergoes oxidation and heating or spontaneous combustion, then the early warning and fire extinguishing work shall be carried out again in accordance with steps a to e.

[0045] Of course, the above description is only a preferred embodiment of the present invention. The present invention is not limited to the above embodiments. It should be noted that any equivalent substitutions or obvious modifications made by those skilled in the art under the guidance of this specification fall within the scope of this specification and should be protected by the present invention.

Claims

1. A device for early warning and prevention of spontaneous combustion of coal in goaf under the goaf mining method, comprising two parts: a fire monitoring and early warning system and a fire prevention system; the fire monitoring and early warning system includes a fire extinguishing sleeve, a temperature sensor, a CO gas concentration sensor, and a control terminal; the fire prevention system includes a nitrogen generator, a nitrogen delivery pipeline, a nitrogen injection pipeline, and a flange. The fireproof sleeve is used to protect the internal nitrogen injection pipeline from being crushed and blocked; the fireproof sleeve extends 10-20cm through the flexible membrane wall into the goaf-side roadway, and a flange is installed at the extended end; the flange is fixed to the fireproof sleeve with bolts; several temperature sensors and CO gas concentration sensors are installed on the inner wall of the fireproof sleeve, and a ring of small ventilation holes is provided around the temperature sensors and CO gas concentration sensors on the surface of the fireproof sleeve to facilitate the detection of gas composition and temperature in the goaf area; The temperature sensor is used to sense the temperature of the goaf area and transmit the data to the control terminal through a signal transmission line; the CO gas concentration sensor is used to detect the CO gas concentration and transmit the data to the control terminal through a signal transmission line; the control terminal is used to determine whether the data collected by the temperature sensor and the CO gas concentration sensor exceed the safety limit, and to activate the fire prevention system when the safety limit is exceeded. The nitrogen delivery pipeline is made of a non-thermal-conducting material; the other end of the nitrogen delivery pipeline is connected to a nitrogen generator; the nitrogen injection pipeline extends from the hole in the middle of the flange and is connected to the nitrogen delivery pipeline; a valve is installed at the connection between the nitrogen delivery pipeline and the nitrogen injection pipeline; the opening and closing of the valve is controlled by a control terminal via radio signals. The nitrogen injection pipe has several nitrogen injection holes evenly opened radially; the nitrogen injection holes are covered by shape memory metal sheets; the shape memory metal sheets completely cover the nitrogen injection holes at room temperature, but will deform when the temperature exceeds the limit, causing the nitrogen injection holes to open. The flange is equipped with an aviation plug; the base of the aviation plug is connected to a temperature sensor and a CO gas concentration sensor via a signal transmission line, and the free end of the aviation plug is connected to a control terminal via a signal transmission line. During the mining of the coal seam face, a flexible membrane wall made of high-water-content material is used to support the roof on one side of the goaf roadway; every 10-15m advance of the working face, fire prevention and extinguishing sleeves are arranged in the goaf area in a direction perpendicular to the axis of the transport roadway and the track roadway.

2. The method of using the early warning and prevention device for spontaneous combustion of coal in the goaf under the goaf-keeping mining method according to claim 1, characterized in that, The application of the above-mentioned device includes the following implementation steps: a. During the advance of the coal seam working face, when the coal in the goaf undergoes oxidation and heating or spontaneous combustion, the temperature sensor and CO gas concentration sensor in the corresponding area will sense the changes in temperature and CO gas concentration, respectively, and transmit the abnormal signal to the control terminal through the signal transmission line. b. After receiving an abnormal signal, the control terminal controls the nitrogen generator to start producing nitrogen and simultaneously uses radio signals to remotely open the valves at the connection points of the nitrogen delivery pipeline and nitrogen injection pipeline in the corresponding area. c. When the temperature exceeds the limit of the shape memory metal sheet at the nitrogen injection hole on the nitrogen injection pipeline, the shape memory metal sheet in the corresponding area deforms, and the nitrogen injection hole opens; d. The nitrogen generated by the nitrogen generator enters the goaf through the nitrogen delivery pipeline and the nitrogen injection pipeline, and is sprayed out at the nitrogen injection holes opened on the nitrogen injection pipeline, accurately reaching the abnormal area to extinguish the fire; e. When the temperature and CO gas concentration displayed on the control terminal return to normal, turn off the nitrogen generator and valve, the shape memory metal sheet returns to its original state, reseal the nitrogen injection hole, and the fire extinguishing is complete; f. If the coal remaining in other parts of the goaf undergoes oxidation and heating or spontaneous combustion, then the early warning and fire extinguishing work shall be reimplemented in accordance with steps a to e.

Images