Intelligent monitoring and flame-retardant integrated system and method for spontaneous combustion of coal in goaf

Abstract

The invention discloses a goaf coal spontaneous combustion intelligent monitoring and flame retardant integrated system and method, a gas collection device is used for collecting gas at different positions in a goaf and sequentially conveying the gas at different positions to a coal spontaneous combustion detection system; a gas detection module in the coal spontaneous combustion detection system can detect data of flowing gas and feed the detection data back to a coal spontaneous combustion judgment module for analysis and processing to obtain whether coal spontaneous combustion occurs at each position in a goaf and divide the distribution condition of three spontaneous combustion zones in the goaf; if the coal spontaneous combustion condition exists according to the analysis result, the intelligent control system opens a plurality of grouting nozzles around the position and starts a grouting pump, and flame-retardant slurry is injected into the position; according to the invention, spontaneous combustion three-zone distribution and coal spontaneous combustion occurrence conditions can be intelligently and accurately monitored in real time, and according to the coal spontaneous combustion occurrence conditions, accurate positioning and rapid and automatic flame retardant process of goaf coal seam spontaneous combustion are realized, so that the safety of coal mining is guaranteed.

Description

Technical Field

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

[0002] With the increase in the depth and scale of coal mining, the problem of spontaneous combustion of coal seams in goafs is becoming increasingly serious. Due to poor ventilation, oxygen accumulation and heat accumulation, high-temperature zones are easily formed in goafs, which trigger spontaneous combustion of coal seams and lead to fires. The distribution of spontaneous combustion zones in goafs is usually divided into three-zone structures, namely heat dissipation zone, oxidation zone and asphyxiation zone. The dynamic variability of the three spontaneous combustion zones has brought great challenges to coal mine safety management. Traditional monitoring and prevention methods are difficult to meet the needs of rapid and accurate monitoring and efficient fire extinguishing. Existing methods for monitoring spontaneous combustion of coal in goafs of coal mines mostly use manual fixed-point detection, which is inefficient and cannot reflect the temperature and gas concentration changes at various locations in the goaf in real time. Traditional flame retardant technologies, such as simple water injection, gas injection or single chemical injection, are also difficult to effectively cover and control the spontaneous combustion zone, and due to the lack of precise location, they often consume a lot of resources and have limited effects.

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

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

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: an intelligent monitoring and flame retardant integrated system for spontaneous combustion of coal in goaf, including a gas collection device, a spontaneous combustion detection system for coal, an intelligent control system and a grouting flame retardant system;

[0006] 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;

[0007] 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;

[0008] 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;

[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, 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.

[0010] Furthermore, 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; the measuring range of the oxygen concentration sensor is 0-25%, the measuring range of the methane concentration sensor is 0-100%, the measuring range of the carbon monoxide concentration sensor is 0-100%, and the measuring range of the carbon dioxide concentration sensor is 0-100%.

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

[0012] Furthermore, 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.

[0013] Furthermore, the gas collection branch pipe is formed by a plurality of hollow pipes with a length of 2m and a diameter of 50mm coaxially connected by sealing threads, and 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] Furthermore, the distance between two adjacent gas collection branch pipes and two adjacent grouting branch pipes in the goaf is 5 to 10 m.

[0015] Furthermore, 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 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 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.

[0016] The working method of the above-mentioned coal spontaneous combustion intelligent monitoring and flame retardant integrated system in goaf area comprises the following specific steps:

[0017] 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;

[0018] B. Coal spontaneous combustion monitoring: Set a program in the PLC controller so that the PLC controller controls the opening of 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, the coal spontaneous combustion detection system is controlled 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 conditions, and feeds back the information to the PLC controller;

[0019] 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;

[0020] 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.

[0021] Furthermore, in step B, the coal spontaneous combustion determination module determines the coal spontaneous combustion situation according to the collected gas data as follows:

[0022] 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;

[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 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;

[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 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;

[0025] 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 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.

[0026] Compared with the prior art, the present invention adopts a combination of a gas collection device, a coal spontaneous combustion detection system, an intelligent control system and a grouting flame retardant system. The gas collection device is used to collect gas at different positions in the goaf, and the gas collected at different positions is sequentially transported to the coal spontaneous combustion detection system; the gas detection module in the coal spontaneous combustion detection system can detect the data of the gas flowing through, and feed the detection data back to the coal spontaneous combustion determination module for analysis and processing, so as to obtain whether coal spontaneous combustion occurs at various positions in the goaf, and divide the distribution of the three spontaneous combustion zones in the goaf according to the gas data at different positions, and then feed the analysis results back to the Intelligent control system. If there is coal spontaneous combustion according to the analysis results, the intelligent control system controls the grouting and flame retardant system to open multiple grouting nozzles around the position and start the grouting pump to inject flame retardant slurry into the position. During the grouting process, the coal spontaneous combustion detection system collects gas data in real time until it is determined that the coal spontaneous combustion at the position has stopped. Then the grouting is stopped and the subsequent normal processing of the working face is carried out. The present invention can intelligently, accurately and real-time monitor the distribution of the three zones of spontaneous combustion and the occurrence of coal spontaneous combustion, and according to the occurrence of coal spontaneous combustion, it can realize the precise positioning of the spontaneous combustion of the coal seam in the goaf and the rapid and automated flame retardant process to ensure the safety of coal 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 structural schematic diagram of the coal spontaneous combustion detection system of 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 structural schematic diagram of the grouting nozzle in the present invention.

[0031] In the figure: 1-working face, 2-goaf, 3-air inlet lane, 4-return air lane, 5-gas collection branch pipe, 6-filter, 7-sealing plug one, 8-tee, 9-right angle elbow, 10-valve switch, 11-shell, 12-micro 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 judgment module, 15-gas pipe, 16-quick plug connector, 17-grouting main pipe, 18-grouting nozzle, 181-nozzle, 19-grouting pump, 20-slurry storage device, 21-sealing plug two, 22-PLC controller, 23-display device, 24-control valve two, 25-control valve one. DETAILED DESCRIPTION

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

[0033] like Figure 1 As shown, an intelligent monitoring and flame retardant integrated system for spontaneous combustion of coal in goaf areas includes a gas collection device, a spontaneous combustion detection system for coal, an intelligent control system and a grouting flame retardant system;

[0034] The gas collection device comprises a gas collection main pipe and a plurality of gas collection branch pipes 5, one end of each of the plurality of gas collection branch pipes 5 extends into the goaf 2, and each end is provided with a sealing plug 7, and each of the gas collection branch pipes 5 is 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, and a plurality of gas collection ports are arranged at equal intervals on the gas collection branch pipes 5 in the goaf, and the gas collection ports are used to collect gas samples from the respective surrounding environments; 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 flame retardant system comprises a grouting main pipe 17, a grouting pump 19, a grouting storage device 20 and a plurality of grouting branches, one end of each of the plurality of grouting branches extends into the goaf respectively, and the ends are equipped with sealing plugs 2, each grouting branch pipe corresponds to a gas collection branch pipe 5, and the grouting branches are arranged at equal intervals and parallel to each other; the other ends of the plurality of grouting branches are connected to the grouting main pipe 17, and a plurality of grouting nozzles 18 are provided on the grouting branches in the goaf 2, and the positions and numbers of the grouting nozzles 18 correspond one-to-one with the gas collection ports of the respective corresponding gas collection branch pipes 5, so as to perform grouting flame retardant at the respective positions; Figure 4 As shown, each grouting nozzle 18 is equipped with a control valve 24 for controlling the opening and closing of the grouting nozzle 18; the grouting main pipe 17 is connected to the slurry storage device 20 through the grouting pump 19, and the slurry storage device 20 contains flame retardant slurry. The grouting pump 19 is used to transport the flame retardant slurry through the grouting main pipe 17 to each grouting branch pipe to perform grouting and flame retardant at the required position of the goaf; the grouting nozzle 18 is cylindrical, and a circle of nozzles 181 are evenly arranged on the side of the cylinder. When opened, it can spray the flame retardant slurry to the surrounding area 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 to 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 control valve 1 25, the control valve 2 24 and the display device 23, and is used to control the opening of different control valves 1 25 and obtain the 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 19 and the corresponding control valve 2 24, and grouting is performed on the location where the coal spontaneous combustion is determined to occur to prevent combustion. At the same time, the location where the coal spontaneous combustion occurs 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 5-10 m.

[0039] The working method of the above-mentioned coal spontaneous combustion intelligent monitoring and flame retardant integrated system in goaf area comprises the following specific steps:

[0040] A. Deployment of the integrated system for intelligent monitoring of spontaneous combustion of coal and flame retardancy: First, determine the spacing d and length L of adjacent gas collection branch pipes 5 and adjacent grouting branch pipes according to the size of the goaf. Based on the determined spacing d and length L, pre-bury the gas collection branch pipe 5 and the grouting branch pipe at the corresponding positions of the goaf, number the gas collection ports on the gas collection branch pipe 5 and the grouting nozzles 18 on the grouting branch pipe in turn, record the positions of each numbered gas collection port and grouting nozzle 18 and store them in the coal spontaneous combustion determination module 14, then connect each component in turn to complete the deployment of the integrated system for intelligent monitoring of spontaneous combustion of coal and flame retardancy.

[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. According to claim 1, the intelligent monitoring and flame retardant integrated system for spontaneous combustion of coal in goaf 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 integrated system for intelligent monitoring and flame retardancy of 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 branch pipes and two adjacent grouting branch pipes 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 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 so that the PLC controller controls the opening of 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, the coal spontaneous combustion detection system is controlled 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 conditions, and feeds back the information to the PLC controller; 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.

9. The working method according to claim 8, characterized in that: In step B, the coal spontaneous combustion determination module determines the coal spontaneous combustion situation according to the collected gas data as follows: 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 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.

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