An intelligent monitoring and flame retardant integrated system and method for spontaneous combustion of coal in goaf

Abstract

The present invention discloses an intelligent monitoring and flame retardant integration system and method for coal spontaneous combustion in goafs. The gas collection device is used to collect gases at different positions in the goaf and sequentially transport the gases at different positions to the coal spontaneous combustion detection system. The gas detection module in the coal spontaneous combustion detection system can detect the data of the flowing-through gases and feedback the detection data to the coal spontaneous combustion determination module for analysis and processing, so as to obtain whether coal spontaneous combustion occurs at each position in the goaf and the distribution of the three spontaneous combustion zones in the goaf. If there is a situation of coal spontaneous combustion according to the analysis result, the intelligent control system will open multiple grouting nozzles around this position and start the grouting pump to inject flame retardant slurry into this position. The present invention can intelligently, accurately and real-time monitor the distribution of the three spontaneous combustion zones and the occurrence of coal spontaneous combustion, and according to the occurrence of coal spontaneous combustion, realize the precise positioning and rapid automatic flame retardant process of coal seam spontaneous combustion in the goaf to ensure the safety of coal mine mining.

Description

Technical Field

[0001] The present invention belongs to the field of coal mine fire prevention and control, and particularly relates to an intelligent monitoring and flame retardant integration system and method for coal spontaneous combustion in goafs. Background Art

[0002] With the increase in the depth and scale of coal mining, the problem of spontaneous combustion of coal seams in goafs has become increasingly serious. Due to poor ventilation, oxygen accumulation and heat accumulation in the coal seams of goafs, high-temperature areas are extremely likely to form, triggering spontaneous combustion of coal seams and causing fires. The distribution of the spontaneous combustion zone in goafs is usually divided into a three-zone structure, namely, a heat dissipation zone, an oxidation zone and an asphyxiation zone. The dynamic changes of the three spontaneous combustion zones pose great challenges to coal mine safety management, and traditional monitoring and prevention methods are difficult to meet the requirements of rapid and accurate monitoring and efficient fire extinguishing. The existing monitoring methods for coal spontaneous combustion in coal mine goafs mostly adopt manual fixed-point detection, which is inefficient and cannot reflect the temperature and gas concentration changes at each position in the goaf in real time. Traditional flame retardant technologies, such as simple water injection, gas injection or single chemical agent injection, are also difficult to effectively cover and control the spontaneous combustion area, and due to inaccurate positioning, a large amount of resources are often consumed and the effect is limited.

[0003] Therefore, in order to improve the accuracy of coal spontaneous combustion monitoring in goafs and the effectiveness of flame retardancy, there is an urgent need for a system and method that can intelligently, accurately and real-time monitor the distribution of the three spontaneous combustion zones and the occurrence of coal spontaneous combustion, and according to the occurrence of coal spontaneous combustion, achieve precise positioning and rapid automatic flame retardant process of coal seam spontaneous combustion in goafs to ensure the safety of coal mining, which is the research direction required by the present invention. Summary of the Invention

[0004] Aiming at the problems existing in the above-mentioned prior art, the present invention provides an intelligent monitoring and flame retardant integration system and method for coal spontaneous combustion in goafs, which can intelligently, accurately and real-time monitor the distribution of the three spontaneous combustion zones and the occurrence of coal spontaneous combustion, and according to the occurrence of coal spontaneous combustion, achieve precise positioning and rapid automatic flame retardant process of coal seam spontaneous combustion in goafs to ensure the safety of coal mining.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is: an intelligent monitoring and flame retardant integration system for coal spontaneous combustion in goafs, comprising a gas collection device, a coal spontaneous combustion detection system, an intelligent control system and a grouting flame retardant system;

[0006] The gas collection device includes a gas collection main pipe and a plurality of gas collection branch pipes. One ends of the plurality of gas collection branch pipes respectively extend into the gob area, and a first sealing plug is installed at each of these ends. The gas collection branch pipes are arranged at equal intervals and parallel to each other. The other ends of the plurality of gas collection branch pipes are all connected to the gas collection main pipe. A plurality of gas collection ports are equally spaced on the gas collection branch pipes located in the gob area. The gas collection ports are used to collect gas samples from the surrounding environment. A filter screen and a first control valve are installed at each gas collection port. The filter screen is used to block coal dust to prevent blockage of the gas collection branch pipes, and the first control valve is used to control the opening and closing of the gas collection port. A valve switch is provided at the end of the gas collection main pipe to control the on-off of the gas collection main pipe.

[0007] The coal spontaneous combustion detection system includes a housing, a micro-extraction pump, a gas detection module, a coal spontaneous combustion determination module, and an air pipe. An air inlet and an air outlet are respectively provided on both sides of the housing. The air pipe is installed inside the housing, and its two ends are respectively connected to the air inlet and the air outlet. The gas collection main pipe is connected to the air inlet through a quick connector to transport the collected gas into the air pipe. The micro-extraction pump is installed on the air pipe to provide a suction negative pressure inside the air pipe. The gas detection module is installed inside the air pipe to detect gas data flowing through the air pipe. The coal spontaneous combustion determination module is connected to the gas detection module to obtain the detection data of the gas detection module, analyze and process it, and then judge the situation of coal spontaneous combustion.

[0008] The grouting fire-retardant system includes a grouting main pipe, a grouting pump, a slurry storage device, and a plurality of grouting branch pipes. One ends of the plurality of grouting branch pipes respectively extend into the gob area, and a second sealing plug is installed at each of these ends. Each grouting branch pipe corresponds to a gas collection branch pipe, and the grouting branch pipes are arranged at equal intervals and parallel to each other. The other ends of the plurality of grouting branch pipes are all connected to the grouting main pipe. A plurality of grouting nozzles are opened on the grouting branch pipes located in the gob area, and the positions and numbers of the grouting nozzles correspond one-to-one with the gas collection ports of their corresponding gas collection branch pipes, and are used to perform grouting fire-retardant at their respective positions. A second control valve is installed at each grouting nozzle to control the opening and closing of the grouting nozzle. The grouting main pipe is connected to the slurry storage device through the grouting pump. The slurry storage device contains fire-retardant slurry, and the grouting pump is used to transport the fire-retardant slurry through the grouting main pipe to each grouting branch pipe to perform grouting fire-retardant at the required positions in the gob area.

[0009] The intelligent control system includes a PLC controller and a display device. The PLC controller is connected to the coal spontaneous combustion detection system, the grouting pump, the first control valve, the second control valve, and the display device. It is used to control the opening of different first control valves and obtain the detection data fed back by the coal spontaneous combustion detection system. If there is coal spontaneous combustion, it issues an instruction to start the grouting pump and the corresponding second control valve to perform grouting fire-retardant on the position where coal spontaneous combustion is judged. At the same time, it displays the position where coal spontaneous combustion exists in the gob area through the display device.

[0010] Further, the gas detection module includes an oxygen concentration sensor, a methane concentration sensor, a carbon monoxide concentration sensor, and a carbon dioxide concentration sensor. The trachea is made of PVC fire-retardant pipe. The measurement range of the oxygen concentration sensor is 0-25%, the measurement range of the methane concentration sensor is 0-100%, the measurement range of the carbon monoxide concentration sensor is 0-100%, and the measurement range of the carbon dioxide concentration sensor is 0-100%.

[0011] Further, the distance between adjacent gas collection ports on the gas collection branch pipe is 4-6 meters.

[0012] Further, the grouting nozzle is cylindrical, and a circle of nozzles is evenly arranged on the side surface of the cylinder. When it is opened, it can spray fire-retardant slurry around in a rotating and lifting manner, so that the slurry covers the surrounding coal body. The maximum coverage radius of the sprayed slurry is 10-15m.

[0013] Further, the gas collection branch pipe is composed of multiple hollow pipes with a length of 2m and a diameter of 50mm connected coaxially through sealed threads. The length of the gas collection branch pipe is adjusted according to the depth of the goaf. The hollow pipe is made of aluminum-plastic material.

[0014] Further, the distance between adjacent two gas collection branch pipes and adjacent two grouting branch pipes in the goaf is 5-10m.

[0015] Further, the coal spontaneous combustion determination module automatically divides the distribution of the three spontaneous combustion zones in the goaf and determines the location of the coal spontaneous combustion area according to the gas data fed back by the gas collection ports at different positions in the goaf. According to the oxygen concentration detected by the gas detection module, 8% and 18% are used as critical values respectively to divide the distribution of the three spontaneous combustion zones in the goaf, and the detection data at different positions are compared with the preset threshold values to determine the location of the coal spontaneous combustion area, and the information is fed back to the PLC controller.

[0016] The working method of the above intelligent monitoring and flame retardant integration system for coal spontaneous combustion in the goaf is as follows:

[0017] A. Install the intelligent monitoring and flame retardant integration system for coal spontaneous combustion: First, determine the distance d and length L between adjacent gas collection branch pipes and adjacent grouting branch pipes according to the size of the goaf. According to the determined distance d and length L, bury the gas collection branch pipes and grouting branch pipes in the corresponding positions of the goaf respectively. Number the gas collection ports on the gas collection branch pipes and the grouting nozzles on the grouting branch pipes in sequence, record the positions of each numbered gas collection port and grouting nozzle and store them in the coal spontaneous combustion determination module, and then connect each component in sequence to complete the installation of the intelligent monitoring and flame retardant integration system for coal spontaneous combustion;

[0018] B. Coal spontaneous combustion monitoring: Set a program in the PLC controller to make the PLC controller control the opening of the control valve 1 of each gas collection port in sequence according to the gas collection port number. When the control valve 1 of each gas collection port is opened, control the coal spontaneous combustion detection system to collect the gas conditions at the corresponding position. The gas detection module alternately transmits the gas data detected at each position to the coal spontaneous combustion determination module. The coal spontaneous combustion determination module analyzes and determines the coal spontaneous combustion situation of this position data and feeds back this information to the PLC controller;

[0019] C. Grouting for fire retardancy: The PLC controller receives the information fed back by the coal spontaneous combustion determination module. When it detects that the gas collected at a gas collection port with a certain number has a tendency of coal spontaneous combustion or coal spontaneous combustion occurs, the PLC controller sends an opening instruction to the control valve 2 of the grouting nozzle corresponding to this numbered gas collection port and the four adjacent control valves 2 around it, and starts the grouting pump to transport the fire retardant slurry and spray it out from each opened control valve 2 for grouting fire retardancy. During the grouting process, the PLC controller opens the control valve 1 of this numbered gas collection port to continuously collect and detect the gas at this position until the coal spontaneous combustion determination module determines that no coal spontaneous combustion occurs at this position. Then the PLC controller sends a closing instruction to each opened control valve 2 and stops the grouting pump to complete the grouting fire retardancy process;

[0020] D. Movement of the monitoring and fire retardancy system: As the working face continuously advances, the distribution range of the three spontaneous combustion zones in the goaf also changes accordingly. According to the continuous detection data of the coal spontaneous combustion detection system, divide the distribution of the three spontaneous combustion zones in the goaf, and move the layout ranges of the gas collection branch pipes and grouting branch pipes in the goaf in the advancing direction of the working face. After the movement, repeat steps B and C to continue monitoring the coal spontaneous combustion situation in the goaf, so as to realize the intelligent monitoring of coal spontaneous combustion at different positions in the goaf and timely grout for fire retardancy when coal spontaneous combustion is found, thereby ensuring the safety of the working face mining.

[0021] Furthermore, the specific method for the coal spontaneous combustion determination module to determine the coal spontaneous combustion situation based on the collected gas data in step B is as follows:

[0022] ①. Set concentration parameter thresholds: Set the oxygen concentration thresholds as S1 and S2 respectively as the preliminary judgment basis. When the oxygen concentration continuously remains lower than S1, it is judged to be in the asphyxiation zone with a relatively low possibility of spontaneous combustion; when the oxygen concentration is between S1 and S2, it enters the attention range of the oxidation spontaneous combustion zone; when the oxygen concentration is greater than S2, it is judged to be in the heat dissipation zone; set the carbon monoxide concentration warning threshold as α. When the carbon monoxide concentration exceeds this value, it indicates that the oxidation reaction of the coal body intensifies and there is a tendency of spontaneous combustion; at the same time, set the danger threshold as β. Exceeding this value indicates that the coal spontaneous combustion situation is relatively serious; set the carbon dioxide concentration threshold as γ. When the carbon dioxide concentration exceeds this value and at the same time the carbon monoxide concentration rises, the possibility of coal spontaneous combustion increases;

[0023] ②. Dynamic analysis of gas concentration change trend: Analyze the collected gas data. If the oxygen concentration is between S1 and S2, and the oxygen concentration shows a continuous downward trend, while the carbon monoxide concentration and carbon dioxide concentration show an upward change, it is judged that there is a trend of coal spontaneous combustion development; when the carbon monoxide concentration continues to rise and the rising rate gradually accelerates, and continues to rise after exceeding the initial warning threshold, it is determined that the risk of coal spontaneous combustion in this area is extremely high; when the carbon dioxide concentration continuously increases with time and the increase amplitude has a certain correlation with the rising trend of the carbon monoxide concentration, and when the carbon dioxide concentration exceeds the set threshold and is accompanied by the carbon monoxide concentration exceeding the warning value, it is judged that the possibility of coal spontaneous combustion is relatively high.

[0024] ③. Gas concentration ratio analysis: Calculate the ratio of carbon monoxide to oxygen concentration ΔCO / ΔO2 in each monitoring data. When the ΔCO / ΔO2 ratio continuously increases, it indicates that the coal oxidation reaction rate accelerates, and the rate of generating carbon monoxide is relatively faster than the rate of oxygen consumption, which means the trend of coal spontaneous combustion is enhanced.

[0025] ④. Comprehensive judgment and decision-making: Combining steps ① to ③, when the oxygen concentration is between S1 and S2, the carbon monoxide concentration exceeds the warning threshold and continues to rise, the carbon dioxide concentration exceeds the threshold, and at the same time, the continuous increase in the ratio of carbon monoxide to oxygen concentration also shows that the coal oxidation reaction intensifies, it is comprehensively determined that coal spontaneous combustion occurs at the current gas collection position in the goaf.

[0026] Compared with the prior art, the present invention combines a gas collection device, a coal spontaneous combustion detection system, an intelligent control system, and a grouting fire-retardant system. The gas collection device is used to collect gases at different positions in the goaf and sequentially transport the gases collected at different positions to the coal spontaneous combustion detection system; the gas detection module in the coal spontaneous combustion detection system can detect the data of the flowing gases and feedback the detection data to the coal spontaneous combustion determination module for analysis and processing, and then obtain whether coal spontaneous combustion occurs at each position in the goaf, and divide the distribution of the three spontaneous combustion zones in the goaf according to the gas data at different positions. Then, the analysis result is fed back to the intelligent control system. If there is a situation of coal spontaneous combustion according to the analysis result, the intelligent control system controls the grouting fire-retardant system to open multiple grouting nozzles around this position and start the grouting pump to inject fire-retardant slurry into this position. During the grouting process, the coal spontaneous combustion detection system continuously collects gas data until it is judged that the coal spontaneous combustion at this position stops, and then the grouting is stopped for the normal processing work of the subsequent working face; the present invention can intelligently, accurately, and real-time monitor the distribution of the three spontaneous combustion zones and the occurrence of coal spontaneous combustion, and according to the occurrence of coal spontaneous combustion, realize the precise positioning of coal seam spontaneous combustion in the goaf and the rapid automatic fire-retardant process to ensure the safety of coal mine mining. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1It is a schematic diagram of the overall structure of the present invention;

[0028] Figure 2 It is a schematic diagram of the structure of the coal spontaneous combustion detection system in the present invention;

[0029] Figure 3 It is a schematic diagram of the structure of the gas collection port in the present invention;

[0030] Figure 4 It is a schematic diagram of the structure of the grouting nozzle in the present invention.

[0031] In the figure: 1 - working face, 2 - gob area, 3 - intake airway, 4 - return airway, 5 - gas collection branch pipe, 6 - filter screen, 7 - first sealing plug, 8 - tee, 9 - right-angle elbow, 10 - valve switch, 11 - housing, 12 - micro gas extraction pump, 13 - gas detection module, 131 - oxygen concentration sensor, 132 - methane concentration sensor, 133 - carbon monoxide concentration sensor, 134 - carbon dioxide concentration sensor, 14 - coal spontaneous combustion determination module, 15 - gas pipe, 16 - quick connector, 17 - grouting main pipe, 18 - grouting nozzle, 181 - nozzle, 19 - grouting pump, 20 - slurry storage device, 21 - second sealing plug, 22 - PLC controller, 23 - display device, 24 - control valve two, 25 - control valve one. Detailed implementation manners

[0032] The present invention will be further described below.

[0033] As Figure 1 shown, an intelligent monitoring and flame retardant integration system for coal spontaneous combustion in the gob area includes a gas collection device, a coal spontaneous combustion detection system, an intelligent control system, and a grouting flame retardant system;

[0034] The gas collection device includes a gas collection main pipe and a plurality of gas collection branch pipes 5. One ends of the plurality of gas collection branch pipes 5 respectively extend into the gob area 2, and a first sealing plug 7 is installed at this end. The gas collection branch pipes 5 are arranged at equal intervals and parallel to each other; the other ends of the plurality of gas collection branch pipes 5 are connected to the gas collection main pipe through a right-angle elbow 9 or a tee 8. A plurality of gas collection ports are opened at equal intervals on the gas collection branch pipes 5 in the gob area, and the gas collection ports are used to collect gas samples of the surrounding environment; As Figure 3As shown, each gas collection port is equipped with a filter 6 and a control valve 25. The filter 6 is used to block coal dust to prevent clogging of the gas collection branch pipe 5, and the control valve 25 is used to control the opening and closing of the gas collection port; a valve switch 10 is provided at the end of the gas collection main pipe to control the on and off of the gas collection main pipe; the spacing between adjacent gas collection ports on the gas collection branch pipe 5 is 4 to 6 meters. The gas collection branch pipe 5 is formed by coaxially connecting multiple hollow pipes with a length of 2m and a diameter of 50mm through sealing threads. The length of the gas collection branch pipe 5 is adjusted according to the depth of the goaf 2; the hollow pipe is made of aluminum plastic material.

[0035] like Figure 2 As shown, the coal spontaneous combustion detection system includes a shell 11, a micro-extraction pump 12, a gas detection module 13, a coal spontaneous combustion determination module 14 and an air pipe 15. The shell 11 is provided with an air inlet and an exhaust port on both sides. The air pipe 15 is installed in the shell 11 and its two ends are respectively connected to the air inlet and the exhaust port; the gas collection main pipe is connected to the air inlet through a quick-plug connector 16, which is used to transport the collected gas into the air pipe 15; the micro-extraction pump 12 is installed on the air pipe 15, which is used to provide an extraction negative pressure inside the air pipe 15; the gas detection module 13 is installed in the air pipe 15, which is used to detect the gas data flowing through the air pipe 15; the coal spontaneous combustion determination module 14 is connected to the gas detection module 13, which is used to obtain the detection data of the gas detection module 13 and then analyze and process it to determine the coal spontaneous combustion situation; the gas detection module 13 includes an oxygen concentration sensor 131, a methane concentration sensor 132, a carbon monoxide concentration sensor 133 and a carbon dioxide concentration sensor 134, and the air pipe 15 is made of The material is PVC flame retardant pipe; the measuring range of the oxygen concentration sensor 131 is 0-25%, the measuring range of the methane concentration sensor 132 is 0-100%, the measuring range of the carbon monoxide concentration sensor 133 is 0-100%, and the measuring range of the carbon dioxide concentration sensor 134 is 0-100%; the coal spontaneous combustion determination module 14 automatically divides the distribution of the three spontaneous combustion zones in the goaf and determines the location of the coal spontaneous combustion area according to the gas data fed back from the gas collection ports at different positions in the goaf, and divides the distribution of the three spontaneous combustion zones in the goaf with 8% and 18% as the critical values ​​according to the oxygen concentration detected by the gas detection module 13, that is, the oxygen concentration does not exceed 8% for the asphyxiation zone, the oxygen concentration exceeds 8% and does not exceed 18% for the oxidation zone, and the oxygen concentration exceeds 18% for the heat dissipation zone; and compares the detection data at different positions with the preset threshold value to determine the location of the coal spontaneous combustion area, and feeds the information back to the PLC controller 22.

[0036] The grouting fire-retardant system includes a main grouting pipe 17, a grouting pump 19, a slurry storage device 20 and a plurality of grouting branch pipes. One ends of the plurality of grouting branch pipes respectively extend into the goaf, and a second sealing plug is installed at this end. Each grouting branch pipe corresponds to a gas collection branch pipe 5, and the grouting branch pipes are arranged at equal intervals and parallel to each other; the other ends of the plurality of grouting branch pipes are all connected to the main grouting pipe 17. A plurality of grouting nozzles 18 are opened on the grouting branch pipes in the goaf 2, and the positions and quantities of the grouting nozzles 18 correspond one by one to the gas collection ports of their respective corresponding gas collection branch pipes 5, and are used for grouting fire-retardant at their respective positions; as Figure 4 shown, a second control valve 24 is installed at each grouting nozzle 18, and is used to control the opening and closing of the grouting nozzle 18; the main grouting pipe 17 is connected to the slurry storage device 20 through the grouting pump 19. The slurry storage device 20 contains fire-retardant slurry, and the grouting pump 19 is used to transport the fire-retardant slurry through the main grouting pipe 17 to each grouting branch pipe to carry out grouting fire-retardant at the required positions in the goaf; the grouting nozzle 18 is cylindrical, and a circle of nozzles 181 is evenly arranged on the side surface of the cylinder. When opened, it can spray the fire-retardant slurry around in a rotating and lifting manner, so that the slurry covers the surrounding coal body, and the maximum coverage radius of the sprayed slurry is 10-15m.

[0037] The intelligent control system includes a PLC controller 22 and a display device 23. The PLC controller 22 is connected to the coal spontaneous combustion detection system, the grouting pump 19, the first control valve 25, the second control valve 24 and the display device 23, and is used to control the opening of different first control valves 25 and obtain the detection data fed back by the coal spontaneous combustion detection system. If there is coal spontaneous combustion, an instruction is sent to turn on the grouting pump 19 and the corresponding second control valve 24 to carry out grouting fire-retardant at the position where coal spontaneous combustion is judged, and at the same time, the position where coal spontaneous combustion exists in the goaf is displayed through the display device.

[0038] As an improvement of the present invention, the distance between two adjacent gas collection branch pipes 5 and two adjacent grouting branch pipes in the goaf is 5-10m.

[0039] The working method of the above intelligent monitoring and fire-retardant integration system for coal spontaneous combustion in the goaf specifically includes the following steps:

[0040] A. Install the intelligent monitoring and fire-retardant integration system for coal spontaneous combustion: First, determine the distance d and length L between adjacent gas collection branch pipes 5 and adjacent grouting branch pipes according to the size of the goaf. According to the determined distance d and length L, bury the gas collection branch pipes 5 and grouting branch pipes at the corresponding positions in the goaf respectively. Number the gas collection ports on the gas collection branch pipes 5 and the grouting nozzles 18 on the grouting branch pipes in sequence, record the positions of each numbered gas collection port and grouting nozzle 18 and store them in the coal spontaneous combustion determination module 14, and then connect each component in sequence to complete the installation of the intelligent monitoring and fire-retardant integration system for coal spontaneous combustion.

[0041] B. Coal spontaneous combustion monitoring: a program is set in the PLC controller 22 so that the PLC controller 22 controls the control valve 25 of each gas collection port to be opened in sequence according to the order of the gas collection port number, and when the control valve 25 of each gas collection port is opened, the coal spontaneous combustion detection system is controlled to collect the gas conditions at the corresponding position, and the gas detection module 13 transmits the gas data detected at each position to the coal spontaneous combustion determination module 14 in turn, and the coal spontaneous combustion determination module 14 analyzes the position data, determines the coal spontaneous combustion situation, and feeds back the information to the PLC controller 22, and determines the coal spontaneous combustion situation specifically as follows:

[0042] ①, Set the concentration parameter threshold: The oxygen concentration threshold is set at 8% and 18% as the basis for preliminary judgment (adjusted accordingly according to the actual situation of different mines). When the oxygen concentration is continuously lower than 8%, it is judged to be in the asphyxiation zone and the possibility of spontaneous combustion is low; when the oxygen concentration is between 8% and 18%, it enters the attention range of the oxidation spontaneous combustion zone; when the oxygen concentration is greater than 18%, it is judged to be in the heat dissipation zone, but if other steps are judged to be accompanied by abnormal gas concentration changes, the risk of coal spontaneous combustion cannot be ruled out; set the carbon monoxide concentration warning threshold to 50ppm (this value can be adjusted according to the historical data and experience of the mine). When the carbon monoxide concentration exceeds this value, it indicates that the oxidation reaction of the coal body is intensified and there is a tendency for spontaneous combustion to occur; at the same time, set a danger threshold, such as 240ppm (this value can be adjusted according to the historical data and experience of the mine). If it exceeds this value, it indicates that the coal spontaneous combustion is more serious; set the carbon dioxide concentration threshold to 1.5% (this value can be adjusted according to the historical data and experience of the mine). When the carbon dioxide concentration exceeds this value, accompanied by an increase in carbon monoxide concentration, the possibility of coal spontaneous combustion increases;

[0043] ② Dynamic analysis of gas concentration change trend: Analyze the collected gas data. If the oxygen concentration is between 8% and 18%, and the oxygen concentration shows a continuous downward trend, while the carbon monoxide concentration and carbon dioxide concentration show an upward change, it is judged that there is a trend towards coal spontaneous combustion; when the carbon monoxide concentration continues to rise, and the rising rate gradually accelerates, and continues to rise after exceeding the initial warning threshold, it is judged that the risk of coal spontaneous combustion in this area is extremely high; the carbon dioxide concentration continues to increase over time, and the increase has a certain correlation with the rising trend of carbon monoxide concentration. When the carbon dioxide concentration exceeds the set threshold and is accompanied by the carbon monoxide concentration exceeding the warning value, it is judged that the possibility of coal spontaneous combustion is high;

[0044] ③. Gas concentration ratio analysis: Calculate the ratio of carbon monoxide to oxygen concentration ΔCO / ΔO2 in each monitoring data. When the ΔCO / ΔO2 ratio continues to increase, it indicates that the coal oxidation reaction rate is accelerating, and the speed of generating carbon monoxide is faster than the speed of oxygen consumption, which means that the spontaneous combustion trend of coal is increasing. In addition, calculate the ratio of carbon dioxide to carbon monoxide concentration CO2 / CO as needed. If the CO2 / CO ratio is relatively stable and within a certain range, it means that it is currently in a stable state at a certain stage, and can be further judged in combination with other steps.

[0045] ④. Comprehensive judgment and decision: Combining steps ① to ③, when the oxygen concentration is between 8% and 18%, the carbon monoxide concentration exceeds the warning threshold and continues to rise, the carbon dioxide concentration exceeds the threshold, and at the same time, the ratio of carbon monoxide to oxygen concentration continues to increase, which also shows that the coal oxidation reaction has intensified, it is comprehensively judged that coal spontaneous combustion has occurred at the current gas collection location in the goaf.

[0046] C. Grouting flame retardant: The PLC controller 22 receives information fed back by the coal spontaneous combustion determination module 14. When it is detected that the gas collected by a certain numbered gas collection port has a tendency of coal spontaneous combustion or coal spontaneous combustion occurs, the PLC controller 22 sends an opening instruction to the control valve 24 corresponding to the grouting nozzle 18 of the gas collection port with the number and the four surrounding control valves 24, and starts the grouting pump 19 to transport the flame retardant slurry and spray it from each opened control valve 24 for grouting flame retardant. During the grouting process, the PLC controller 22 opens the control valve 125 of the gas collection port with the number, and continuously collects and detects the gas at that position until the coal spontaneous combustion determination module 14 determines that coal spontaneous combustion has not occurred at that position. The PLC controller 22 sends a closing instruction to each opened control valve 24, and stops the grouting pump 19 to complete the grouting flame retardant process.

[0047] D. Movement of the monitoring and flame retardant system: As the working face continues to advance, the distribution range of the three spontaneous combustion zones in the goaf also changes accordingly. According to the continuous detection data of the coal spontaneous combustion detection system, the distribution of the three spontaneous combustion zones in the goaf is divided, and according to the advancement of the working face, the layout range of the gas collection branch pipe 5 and the grouting branch pipe are translated in the goaf 2 toward the direction of the working face advancement. After the translation, repeat steps B and C to continue monitoring the spontaneous combustion of coal in the goaf, thereby realizing intelligent monitoring of coal spontaneous combustion at different locations in the goaf, and timely grouting and flame retardant when coal spontaneous combustion is found, thereby ensuring the safety of working face mining.

[0048] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An intelligent monitoring and flame retardant integrated system for spontaneous combustion of coal in goaf, characterized in that: It includes gas collection device, coal spontaneous combustion detection system, intelligent control system and grouting flame retardant system; The gas collection device comprises a gas collection main pipe and a plurality of gas collection branch pipes, one end of each of the plurality of gas collection branch pipes respectively extends into the goaf, and each end is provided with a sealing plug, and each of the gas collection branch pipes is arranged at equal intervals and in parallel with each other; the other ends of the plurality of gas collection branch pipes are connected to the gas collection main pipe, and a plurality of gas collection ports are provided at equal intervals on the gas collection branch pipes in the goaf, and the gas collection ports are used to collect gas samples from their respective surrounding environments; each gas collection port is provided with a filter screen and a control valve, the filter screen is used to block coal dust to prevent clogging of the gas collection branch pipe, and the control valve is used to control the opening and closing of the gas collection port; a valve switch is provided at the end of the gas collection main pipe, which is used to control the on and off of the gas collection main pipe; The coal spontaneous combustion detection system includes a shell, a micro-extraction pump, a gas detection module, a coal spontaneous combustion determination module and an air pipe. An air inlet and an air outlet are respectively arranged on both sides of the shell. The air pipe is installed in the shell and its two ends are respectively connected to the air inlet and the air outlet; the gas collection main pipe is connected to the air inlet through a quick-plug connector, which is used to transport the collected gas into the air pipe; the micro-extraction pump is installed on the air pipe, which is used to provide an extraction negative pressure inside the air pipe; the gas detection module is installed in the air pipe, which is used to detect the gas data flowing through the air pipe; the coal spontaneous combustion determination module is connected to the gas detection module, which is used to obtain the detection data of the gas detection module and then analyze and process it to determine the coal spontaneous combustion situation; The grouting flame retardant system comprises a grouting main pipe, a grouting pump, a grouting storage device and a plurality of grouting branches, one end of each of the plurality of grouting branches respectively extends into the goaf, and the ends are all provided with two sealing plugs, each grouting branch pipe corresponds to a gas collection branch pipe, and the various grouting branches are arranged at equal intervals and in parallel with each other; the other ends of the plurality of grouting branches are all connected to the grouting main pipe, a plurality of grouting nozzles are provided on the grouting branches in the goaf, and the positions and numbers of the grouting nozzles correspond one-to-one with the gas collection ports of the respective corresponding gas collection branches, so as to perform grouting flame retardant at the respective positions; a control valve two is provided at each grouting nozzle, so as to control the opening and closing of the grouting nozzle; the grouting main pipe is connected to the grouting storage device through the grouting pump, and the flame retardant slurry is contained in the grouting storage device, and the grouting pump is used to transport the flame retardant slurry to the various grouting branches through the grouting main pipe, so as to perform grouting flame retardant at the required positions in the goaf; The intelligent control system includes a PLC controller and a display device. The PLC controller is connected to the coal spontaneous combustion detection system, a grouting pump, control valve one, control valve two and the display device, and is used to control the opening of different control valves and obtain detection data fed back by the coal spontaneous combustion detection system. If coal spontaneous combustion occurs, a command is issued to start the grouting pump and the corresponding control valve two, and grouting and flame retardant are performed on the location where the coal spontaneous combustion is judged. At the same time, the location where the coal spontaneous combustion occurs in the goaf is displayed through the display device.

2. According to claim 1, the integrated system for intelligent monitoring and flame retardancy of spontaneous combustion of coal in goaf is characterized in that: The gas detection module includes an oxygen concentration sensor, a methane concentration sensor, a carbon monoxide concentration sensor and a carbon dioxide concentration sensor, and the gas pipe is made of PVC flame-retardant pipe.

3. The intelligent monitoring and flame retardant integrated system for spontaneous combustion of coal in goaf according to claim 1 is characterized in that: The distance between adjacent gas collection ports on the gas collection branch pipe is 4 to 6 meters.

4. The intelligent monitoring and flame retardant integrated system for spontaneous combustion of coal in goaf according to claim 1 is characterized in that: The grouting nozzle is cylindrical, and a circle of nozzles are evenly arranged on the side of the cylinder. When opened, it can spray flame retardant slurry around in a rotating and lifting manner, so that the slurry covers the surrounding coal body. The maximum coverage radius of the sprayed slurry is 10 to 15 meters.

5. According to claim 1, the intelligent monitoring and flame retardant integrated system for spontaneous combustion of coal in goaf is characterized in that: The gas collection branch pipe is formed by a plurality of hollow pipes with a length of 2m and a diameter of 50mm connected coaxially through sealing threads. The length of the gas collection branch pipe is adjusted according to the depth of the goaf. The hollow pipe is made of aluminum-plastic material.

6. The intelligent monitoring and flame retardant integrated system for spontaneous combustion of coal in goaf according to claim 1 is characterized in that: The distance between two adjacent gas collection branches and two adjacent grouting branches in the goaf is 5 to 10 meters.

7. The intelligent monitoring and flame retardant integrated system for spontaneous combustion of coal in goaf according to claim 1 is characterized in that: The coal spontaneous combustion judgment module automatically divides the distribution of the three spontaneous combustion zones in the goaf and determines the location of the coal spontaneous combustion area based on the gas data fed back from the gas collection ports at different locations in the goaf. According to the oxygen concentration detected by the gas detection module, 8% and 18% are used as the critical values ​​to divide the distribution of the three spontaneous combustion zones in the goaf, and the detection data at different locations are compared with the pre-set thresholds to determine the location of the coal spontaneous combustion area, and the information is fed back to the PLC controller.

8. A working method of the integrated system for intelligent monitoring and flame retardancy of spontaneous combustion of coal in goaf according to any one of claims 1 to 7, characterized in that: The specific steps are: A. Layout of the integrated system for intelligent monitoring and flame retardant of coal spontaneous combustion: First, determine the spacing d and length L of adjacent gas collection branches and adjacent grouting branches according to the size of the goaf. According to the determined spacing d and length L, pre-bury the gas collection branch and the grouting branch in the corresponding positions of the goaf, number the gas collection ports on the gas collection branch and the grouting nozzles on the grouting branch in turn, record the positions of each numbered gas collection port and grouting nozzle and store them in the coal spontaneous combustion determination module, and then connect each component in turn to complete the layout of the integrated system for intelligent monitoring and flame retardant of coal spontaneous combustion; B. Coal spontaneous combustion monitoring: Set a program in the PLC controller to control the PLC controller to open the control valves of each gas collection port in sequence according to the order of the gas collection port numbers, and when the control valves of each gas collection port are opened, control the coal spontaneous combustion detection system to collect the gas conditions at the corresponding positions. The gas detection module transmits the gas data detected at each position to the coal spontaneous combustion determination module in turn. The coal spontaneous combustion determination module analyzes the position data, determines the coal spontaneous combustion situation, and feeds back the information to the PLC controller. Specifically: ①. Set concentration parameter thresholds: Set the oxygen concentration thresholds to S1 and S2 as the basis for preliminary judgment. When the oxygen concentration is continuously lower than S1, it is judged to be in the asphyxiation zone and the possibility of spontaneous combustion is low; when the oxygen concentration is between S1 and S2, it enters the attention range of the oxidation spontaneous combustion zone; when the oxygen concentration is greater than S2, it is judged to be in the heat dissipation zone; set the carbon monoxide concentration warning threshold to α. When the carbon monoxide concentration exceeds this value, it indicates that the oxidation reaction of the coal body is intensified and there is a tendency for spontaneous combustion to occur; at the same time, set the danger threshold to β. If it exceeds this value, it indicates that the coal spontaneous combustion is more serious; set the carbon dioxide concentration threshold to γ. When the carbon dioxide concentration exceeds this value, accompanied by an increase in carbon monoxide concentration, the possibility of coal spontaneous combustion increases; ② Dynamic analysis of gas concentration change trend: Analyze the collected gas data. If the oxygen concentration is between S1 and S2, and the oxygen concentration shows a continuous downward trend, while the carbon monoxide concentration and carbon dioxide concentration increase, it is judged that there is a trend towards coal spontaneous combustion; when the carbon monoxide concentration continues to rise, and the rate of increase gradually accelerates, and continues to rise after exceeding the initial warning threshold, it is judged that the risk of coal spontaneous combustion in this area is extremely high; the carbon dioxide concentration continues to increase over time, and the increase has a certain correlation with the rising trend of carbon monoxide concentration. When the carbon dioxide concentration exceeds the set threshold and the carbon monoxide concentration exceeds the warning value, it is judged that the possibility of coal spontaneous combustion is high; ③. Gas concentration ratio analysis: Calculate the ratio of carbon monoxide to oxygen concentration ΔCO / ΔO2 in each monitoring data. When the ΔCO / ΔO2 ratio continues to increase, it indicates that the coal oxidation reaction rate is accelerated, and the speed of carbon monoxide generation is faster than the speed of oxygen consumption, which means that the spontaneous combustion trend of coal is enhanced; ④. Comprehensive judgment and decision: Combining steps ① to ③, when the oxygen concentration is between S1 and S2, the carbon monoxide concentration exceeds the warning threshold and continues to rise, the carbon dioxide concentration exceeds the threshold, and the ratio of carbon monoxide to oxygen concentration continues to increase, indicating that the coal oxidation reaction is intensifying, it is comprehensively determined that coal spontaneous combustion occurs at the current gas collection location in the goaf; C. Grouting flame retardant: The PLC controller receives information fed back by the coal spontaneous combustion determination module. When it is detected that the gas collected by a certain numbered gas collection port has a tendency of coal spontaneous combustion or coal spontaneous combustion occurs, the PLC controller sends an opening command to the control valve 2 corresponding to the grouting nozzle of the numbered gas collection port and the four adjacent control valves 2, and starts the grouting pump to transport the flame retardant slurry and spray it from each opened control valve 2 for grouting flame retardant. During the grouting process, the PLC controller opens the control valve 1 of the numbered gas collection port, and continuously collects and detects the gas at this position until the coal spontaneous combustion determination module determines that coal spontaneous combustion has not occurred at this position. The PLC controller sends a closing command to each opened control valve 2, and stops the grouting pump to complete the grouting flame retardant process; D. Movement of the monitoring and flame retardant system: As the working face continues to advance, the distribution range of the three spontaneous combustion zones in the goaf also changes accordingly. According to the continuous detection data of the coal spontaneous combustion detection system, the distribution of the three spontaneous combustion zones in the goaf is divided, and the layout range of the gas collection branch pipe and the grouting branch pipe is translated in the goaf toward the direction of the working face according to the advancement of the working face. After the translation, repeat steps B and C to continue monitoring the spontaneous combustion of coal in the goaf, thereby realizing intelligent monitoring of coal spontaneous combustion at different locations in the goaf, and timely grouting and flame retardant when coal spontaneous combustion is found, thereby ensuring the safety of working face mining.

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