Coal seam spontaneous combustion fire extinguishing technical method

Abstract

The invention discloses a fire extinguishing technical method for spontaneous combustion of a coal seam. The method comprises the following steps: adding 0.5-1% of a foaming agent into slurry through a quantitative foaming agent filling pump; the slurry and the foaming agent are uniformly mixed in the pipeline through the mixer and then enter the foaming device; nitrogen is injected into a foaming device and interacts with slurry containing a foaming agent to generate three-phase foam, then the three-phase foam is injected into a fire extinguishing drill hole through a flow divider, firstly, the fire exposure area range is preliminarily detected through the unmanned aerial vehicle (UAV) infrared thermal imaging technology, and then the detection range is further expanded through a self-spraying and directional drilling method; and a more accurate result can be obtained. In addition, an applicable fire prevention and extinguishing system is constructed, and three-phase foam is injected for heat absorption and cooling. And further using composite colloid to block an air leakage channel, and backfilling loess to prevent after-combustion. The comprehensive detection and control technology can be used for eliminating the spontaneous combustion area of the coal seam and protecting the environment.

Description

Technical Field

[0001] The present invention relates to the technical field of coal mine prevention and control methods, and in particular to a technical method for extinguishing coal seam spontaneous combustion. Background Art

[0002] Continuous natural disasters in coal seams not only lead to a waste of resources, but also cause serious damage to the ecological environment. Previous research on open flame detection has mainly focused on coalfield fire areas, using single methods such as infrared remote sensing or surface temperature measurement, radon measurement, and mercury method. However, in recent years, spontaneous combustion of coal in mines has migrated to deeper areas. Traditional single fire zone detection methods are unable to accurately determine the scope of the fire zone, and inversion interpretation faces the problem of multiple solutions. In fire management, current research focuses on the development of new materials, such as fly ash gel and sodium silicate gel. However, it is often difficult to quickly extinguish spontaneous combustion of coal in mines with a single technology.

[0003] For this reason, a coal seam spontaneous combustion extinguishing technology method needs to be provided. Summary of the Invention

[0004] To address the aforementioned issues with the existing technologies, the present invention provides a method for extinguishing spontaneous coal seam fires. This patented method first uses unmanned aerial vehicle (UAV) infrared thermal imaging technology to initially detect the extent of the exposed fire zone. It then uses self-injection and directional drilling to further expand the detection range and obtain more accurate results. Furthermore, a suitable fire prevention and extinguishing system is constructed, which injects three-phase foam to absorb heat and reduce temperatures. Furthermore, a composite colloid is used to block air leaks, and loess backfill is used to prevent re-ignition. The comprehensive detection and control technology proposed in this patent can be used to eliminate spontaneous coal seam fire zones and protect the environment.

[0005] In order to achieve the above object, the present invention is implemented through the following technical solutions: a technical method for extinguishing spontaneous combustion of coal seams, the fire extinguishing technical method is as follows: Step 1: Determine the scope of the coal mine area; Step 2: The drone's thermal imager collects infrared thermal images to preliminarily identify the suspected fire area; Step 3: Use high-precision ground magnetic survey within the coal mine area. After the coal seam spontaneous combustion, the coal seam roof and floor and interbedded gangue are subjected to high temperature to form burned rocks with thermal remanent magnetism. This can be used to detect hidden fire areas and narrow the scope of the initially delineated fire area. Step 4: Use high-precision magnetic methods to analyze the distribution of the fire area at the detection site by analyzing the burned rock containing ferromagnetic mineral components in the coal seam roof and floor rocks, as well as the strong thermal remanent magnetism retained by the burned rock after the rock cools. Step 5: Through the magnetic method contour map, the burned rock formed after the spontaneous combustion of the coal seam is basically distributed in a horizontal plate-like shape, and the negative anomaly formed under oblique magnetization conditions is relatively strong. Due to the differences in coal seam burial depth, thickness, burned rock morphology, range, and ferromagnetic mineral content, the magnetic anomaly morphology varies in strength, forming a graphical comparative analysis. Step 6: Based on the data detection results of drone infrared thermal imaging and ground high-precision magnetic imaging, four key fire zones were divided. Three circular areas were delineated outward from the center of the key fire zone, with a distance of 50 meters between the circular areas. Holes were drilled at the boundary of each circular area, and the holes at the boundaries of adjacent circular areas were set asymmetrically. Step 7: Monitor the temperature and fire gas of the boundary drill holes. If the temperature and fire gas monitored temperatures remain high, continue to expand the circular area in step 5 and drill holes at the boundary of the circular area to monitor the direction of fire spread. Step 8: Based on the operation steps from 5 to 7, the fire areas are divided into: high-temperature fire treatment area, high-low temperature transition zone fire treatment area, and low-temperature treatment fire treatment area according to temperature and fire gas monitoring; Step 9: The fire extinguishing technology in the high-temperature fire treatment area is as follows: the slurry in the mixing tank is transported to the pipeline through a filter screen, and 0.5-1% foaming agent is added to the slurry via a foaming agent quantitative injection pump; the slurry and foaming agent are evenly mixed in the pipeline through a mixer and then enter the foaming device; in the foaming device, nitrogen is injected and interacts with the slurry containing the foaming agent to form a three-phase foam, which is then injected into the fire extinguishing borehole through a diverter; Step 10: Based on the high temperature treatment in step 9, in order to prevent the hidden high temperature seedlings in the outcrop coal seam from re-burning due to cracks and borehole leakage, composite colloid is used to fill the drill holes and cracks that have met the cooling and fire extinguishing requirements; Step 11: The technical method used to extinguish fires in the high-low temperature transition zone fire treatment area and the low-temperature treatment fire treatment area is as follows: the three-phase foam generated in step 9 is pre-injected into the borehole in the area at one time. When the temperature drops to normal and there is no sign of re-ignition, the composite colloid is injected into the borehole; Step 12: After the composite colloid injection is completed, backfill with loess, with a height of not less than 1.0 meter and a loose paving coefficient of not less than 1.2.

[0006] Preferably, the slurry components in the mixing tank in step 9 are loess and water, the ratio of loess to water is 3:1, and the yellow mud is formed into slurry.

[0007] Preferably, the foaming agent in step 9 is nitrogen foaming agent.

[0008] Preferably, the amount of foaming agent added in step 9 is 1%, the foam expands 30 times, the foam stabilization time is ≥8 hours, a single borehole is filled with 658 cubic meters of yellow mud and 19,740 cubic meters of three-phase foam, and the amount of foaming agent used is 6.6 tons.

[0009] Preferably, the composite colloid in step 10 is prepared by mixing yellow mud, water glass and sodium bicarbonate, wherein the mixing ratio of yellow mud, water glass and sodium bicarbonate is 18:3:1.

[0010] Preferably, a rectangular protection area is extended 5 meters outside the boundary of the low-temperature treatment fire treatment area, 8 holes are evenly drilled in the rectangular protection area, and the drilled holes are respectively injected with composite colloid and covered with loess prepared in step 12.

[0011] In summary, the present invention provides a technical method for extinguishing coal seam spontaneous combustion. By detecting and controlling coal seam outburst fire areas, the present invention provides a new method for preventing and controlling coal seam outburst fire areas, which has broad application prospects. The method and results are summarized as follows: (1) Infrared thermal imaging is only suitable for detecting shallow high-temperature abnormal areas. Combined with high-precision ground magnetic survey, it can accurately delineate the scope of coal seam fire areas, laying the foundation for subsequent fire area management.

[0012] (2) The application of comprehensive fire prevention and fire extinguishing technologies, such as three-phase foam grouting for fire extinguishing and cooling, colloid injection for plugging leaks, and loess backfilling for preventing re-ignition, can effectively eliminate the threat of exposed fire areas and ensure safe production in coal mines. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of the high-temperature spontaneous combustion area and drilling distribution in the technical method of the present invention; Figure 2 It is a schematic diagram of the magnetic method contour line plane diagram of the present invention; DETAILED DESCRIPTION

[0014] The present invention will be further described below with reference to the embodiments.

[0015] like Figures 1 to 2 As shown: During the initial treatment phase, spontaneous combustion was severe in the high-temperature fire treatment area. Temperature measurements through drilling revealed temperatures as high as 280°C in some wellbores within the designated fire zone. The wellbore temperatures were extremely high, as were levels of gases indicative of spontaneous combustion, such as carbon monoxide (up to 1×105 ppm). In addition, significant amounts of water vapor and smoke were observed in the wellbore within the fire zone, indicating the intensity of the fire prior to treatment. Analysis focused on the concentration and temperature of carbon monoxide, an indicator gas, within the boreholes. Specifically, a portable sampling pump was used to extract the indicator gas from the boreholes and subsequently monitored using a gas chromatograph. The borehole temperature was measured directly by a thermocouple. When the risk of spontaneous combustion in the high-temperature fire treatment area increased, a fire suppression system was immediately deployed and three-phase foam was injected. Following these measures, the wellbore temperature dropped sharply, showing a clear downward trend, while the carbon monoxide concentration lagged behind and rebounded to a certain level. This phenomenon is attributed to the fact that when the three-phase foam acts on the spontaneously combusting coal, it instantly dissipates heat from the high-temperature coal, rapidly reducing the wellbore temperature. However, due to the large area of the fire and the extensive heat exchange required, the fire was not completely extinguished. Furthermore, under the influence of the fractures, the gas indicating spontaneous combustion did not change significantly. Subsequently, a composite colloid was injected into the fractures, effectively filling the cracks in the overlying strata above the outcropping coal seam. These treatment measures successfully controlled the indicator gas and wellbore temperature in the fire zone, preventing the fire zone from spontaneously igniting again.

[0016] The present invention is a technical method for extinguishing spontaneous combustion of coal seams. The specific technical method for extinguishing spontaneous combustion of coal seams is as follows: Step 1: Determine the scope of the coal mine area; Step 2: The drone's thermal imager collects infrared thermal images to preliminarily identify the suspected fire area; Step 3: Use high-precision ground magnetic survey within the coal mine area. After the coal seam spontaneous combustion, the coal seam roof and floor and interbedded gangue are subjected to high temperature to form burned rocks with thermal remanent magnetism. This can be used to detect hidden fire areas and narrow the scope of the initially delineated fire area. Step 4: Use high-precision magnetic methods to analyze the distribution of the fire area at the detection site by analyzing the burned rock containing ferromagnetic mineral components in the coal seam roof and floor rocks, as well as the strong thermal remanent magnetism retained by the burned rock after the rock cools. Step 5: Through the magnetic method contour map, the burned rock formed after the spontaneous combustion of the coal seam is basically distributed in a horizontal plate-like shape, and the negative anomaly formed under oblique magnetization conditions is relatively strong. Due to the differences in coal seam burial depth, thickness, burned rock morphology, range, and ferromagnetic mineral content, the magnetic anomaly morphology varies in strength, forming a graphical comparative analysis. Step 6: Based on the data detection results of drone infrared thermal imaging and ground high-precision magnetic imaging, four key fire zones were divided. Three circular areas were delineated outward from the center of the key fire zone, with a distance of 50 meters between the circular areas. Holes were drilled at the boundary of each circular area, and the holes at the boundaries of adjacent circular areas were set asymmetrically. Step 7: Monitor the temperature and fire gas of the boundary drill holes. If the temperature and fire gas monitored temperatures remain high, continue to expand the circular area in step 5 and drill holes at the boundary of the circular area to monitor the direction of fire spread. Step 8: Based on the operation steps from 5 to 7, the fire areas are divided into: high-temperature fire treatment area, high-low temperature transition zone fire treatment area, and low-temperature treatment fire treatment area according to temperature and fire gas monitoring; Step 9: The fire extinguishing technology in the high-temperature fire treatment area is as follows: the slurry in the mixing tank is transported to the pipeline through a filter screen, and 0.5-1% foaming agent is added to the slurry via a foaming agent quantitative injection pump; the slurry and foaming agent are evenly mixed in the pipeline through a mixer and then enter the foaming device; in the foaming device, nitrogen is injected and interacts with the slurry containing the foaming agent to form a three-phase foam, which is then injected into the fire extinguishing borehole through a diverter; Step 10: Based on the high temperature treatment in step 9, in order to prevent the hidden high temperature seedlings in the outcrop coal seam from re-burning due to cracks and borehole leakage, composite colloid is used to fill the drill holes and cracks that have met the cooling and fire extinguishing requirements; Step 11: The technical method used to extinguish fires in the high-low temperature transition zone fire treatment area and the low-temperature treatment fire treatment area is as follows: the three-phase foam generated in step 9 is pre-injected into the borehole in the area at one time. When the temperature drops to normal and there is no sign of re-ignition, the composite colloid is injected into the borehole; Step 12: After the composite colloid injection is completed, backfill with loess, with a height of not less than 1.0 meter and a loose paving coefficient of not less than 1.2.

[0017] In at least one embodiment, the slurry components in the mixing tank in step 9 are loess and water, and the ratio of loess to water is 3:1, and the yellow mud is formed into slurry.

[0018] In at least one embodiment, the foaming agent in step 9 is nitrogen.

[0019] In at least one embodiment, the amount of foaming agent added in step 9 is 1%, the foam expands 30 times, the foam stabilization time is ≥8 hours, a single borehole is filled with 658 cubic meters of yellow mud and 19,740 cubic meters of three-phase foam, and the amount of foaming agent used is 6.6 tons.

[0020] In at least one embodiment, the composite colloid in step 10 is prepared by mixing yellow mud, water glass, and sodium bicarbonate in a ratio of 18:3:1.

[0021] In at least one embodiment, a rectangular protection area is extended 5 meters outside the boundary of the low-temperature fire treatment area, and 8 holes are evenly drilled in the rectangular protection area. The holes are respectively injected with composite colloid and covered with loess prepared in step 12.

[0022] The embodiments of the present invention are only used to illustrate the present invention and do not limit the scope of the claims. Other substantially equivalent alternatives that can be thought of by those skilled in the art are all within the scope of protection of the present invention.

Claims

1. A coal seam spontaneous combustion extinguishing technology method, characterized in that: Fire extinguishing techniques are as follows: Step 1: Determine the scope of the coal mine area; Step 2: The drone's thermal imager collects infrared thermal images to preliminarily identify the suspected fire area; Step 3: Use high-precision ground magnetic survey within the coal mine area. After the coal seam spontaneous combustion, the coal seam roof and floor and interbedded gangue are subjected to high temperature to form burned rocks with thermal remanent magnetism. This can be used to detect hidden fire areas and narrow the scope of the initially delineated fire area. Step 4: Use high-precision magnetic methods to analyze the distribution of the fire area at the detection site by analyzing the burned rock containing ferromagnetic mineral components in the coal seam roof and floor rocks, as well as the strong thermal remanent magnetism retained by the burned rock after the rock cools. Step 5: Through the magnetic method contour map, the burned rock formed after the spontaneous combustion of the coal seam is basically distributed in a horizontal plate-like shape, and the negative anomaly formed under oblique magnetization conditions is relatively strong. Due to the differences in coal seam burial depth, thickness, burned rock morphology, range, and ferromagnetic mineral content, the magnetic anomaly morphology varies in strength, forming a graphical comparative analysis. Step 6: Based on the data detection results of drone infrared thermal imaging and ground high-precision magnetic imaging, four key fire zones were divided. Three circular areas were delineated outward from the center of the key fire zone, with a distance of 50 meters between the circular areas. Holes were drilled at the boundary of each circular area, and the holes at the boundaries of adjacent circular areas were set asymmetrically. Step 7: Monitor the temperature and fire gas of the boundary drill holes. If the temperature and fire gas monitored temperatures remain high, continue to expand the circular area in step 5 and drill holes at the boundary of the circular area to monitor the direction of fire spread. Step 8: Based on the operation steps from 5 to 7, the fire areas are divided into: high-temperature fire treatment area, high-low temperature transition zone fire treatment area, and low-temperature treatment fire treatment area according to temperature and fire gas monitoring; Step 9: The fire extinguishing technology in the high-temperature fire treatment area is as follows: the slurry in the mixing tank is transported to the pipeline through a filter screen, and 0.5-1% foaming agent is added to the slurry via a foaming agent quantitative injection pump; the slurry and foaming agent are evenly mixed in the pipeline through a mixer and then enter the foaming device; in the foaming device, nitrogen is injected and interacts with the slurry containing the foaming agent to form a three-phase foam, which is then injected into the fire extinguishing borehole through a diverter; Step 10: Based on the high temperature treatment in step 9, in order to prevent the hidden high temperature seedlings in the outcrop coal seam from re-burning due to cracks and borehole leakage, composite colloid is used to fill the drill holes and cracks that have met the cooling and fire extinguishing requirements; Step 11: The technical method used to extinguish fires in the high-low temperature transition zone fire treatment area and the low-temperature treatment fire treatment area is as follows: the three-phase foam generated in step 9 is pre-injected into the borehole in the area at one time. When the temperature drops to normal and there is no sign of re-ignition, the composite colloid is injected into the borehole; Step 12: After the composite colloid injection is completed, backfill with loess, with a height of not less than 1.0 meter and a loose paving coefficient of not less than 1.

2.

2. A coal seam spontaneous combustion extinguishing technology method according to claim 1, characterized in that: Step 9: The slurry components in the mixing tank are loess and water, the ratio of loess to water is 3:1, and the yellow mud becomes slurry.

3. A coal seam spontaneous combustion extinguishing technology method according to claim 1, characterized in that: The foaming agent in step 9 is nitrogen foaming agent.

4. A coal seam spontaneous combustion extinguishing technology method according to claim 1, characterized in that: In step 9, the amount of foaming agent added is 1%, the foam expands 30 times, the foam stabilization time is ≥8 hours, a single borehole is filled with 658 cubic meters of yellow mud and 19,740 cubic meters of three-phase foam, and the amount of foaming agent used is 6.6 tons.

5. A coal seam spontaneous combustion extinguishing technology method according to claim 1, characterized in that: The composite colloid in step 10 is prepared by mixing yellow mud, water glass and sodium bicarbonate in a ratio of 18:3:

1.

6. A coal seam spontaneous combustion extinguishing technology method according to claim 1, characterized in that: A rectangular protection area is expanded 5 meters outside the boundary of the low-temperature treatment fire treatment area. 8 holes are evenly drilled in the rectangular protection area. The holes are injected with composite colloid and covered with loess prepared in step 12.

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