An automatic control method for fire prevention and extinguishment in a well

Abstract

The application discloses an automatic control method for fire prevention and extinguishment in a mine, which comprises the following steps: establishing an automatic control system for fire prevention and extinguishment, wherein the automatic control system for fire prevention and extinguishment comprises a nitrogen injection and grouting system, a control center and temperature sensors, oxygen concentration sensors and CO concentration sensors which are arranged in a continuous moving mode and follow a coal mining face, the temperature sensors, the oxygen concentration sensors and the CO concentration sensors are connected to the control center through a CAN data bus, the control center is connected to a nitrogen injection machine and a grouting machine of the nitrogen injection and grouting system through a PLC controller via the CAN data bus, the automatic control method for fire prevention and extinguishment is provided for unmanned operation mining of coal, and the method has the advantages of high practicability, convenient operation and safety. In the case of a spontaneous combustion sign, the method can remotely and quickly give a warning and take action to prevent a fire, the reaction time of the method is short, and the method can be completed in 5 minutes, all operations can be remotely performed, and the safety of personnel is ensured.

Description

Technical Field

[0001] This invention relates to an automatic control method for fire prevention and extinguishing in underground mines. Background Technology

[0002] With the deepening of the concept of efficient, green, and intelligent coal mining in my country, and the continuous progress of mining technology and equipment, intelligent unmanned coal mining has become an important development direction for coal mining in my country. However, at the same time, it has put forward new challenges and pressures on mine fire prevention and extinguishing work. In actual coal production, spontaneous combustion of coal occurs from time to time. Once a spontaneous combustion fire occurs in a mine, it not only wastes resources, but also brings huge hidden dangers to coal mine production. Summary of the Invention

[0003] This invention proposes an automatic fire prevention and extinguishing control method for underground coal mining. This method is applicable to unmanned coal mining operations. The control center determines the gas concentration for early warning actions based on the spontaneous combustion period of the coal seam, the width of the three spontaneous combustion zones in the goaf, and the spontaneous combustion indicator gases. When the gas concentration measured in the goaf or the sealed area of ​​the connecting roadway exceeds the limit, an early warning signal is immediately issued. Nitrogen injection mode is activated when engineers and the intelligent judgment module determine that nitrogen injection is necessary. When a gas indicating open flame is detected in the gas, early warning signals are immediately issued both underground and on the surface, and grouting mode is activated when engineers and the intelligent judgment module determine that grouting is necessary.

[0004] To achieve the above objectives, the technical solution proposed by this invention is as follows:

[0005] An automatic fire prevention and extinguishing control method for underground mining includes establishing an automatic fire prevention and extinguishing control system. The automatic fire prevention and extinguishing control system includes a nitrogen injection and grouting system, a control center, and temperature sensors, oxygen concentration sensors, and CO concentration sensors that move continuously with the coal face. The temperature sensors, oxygen concentration sensors, and CO concentration sensors are connected to the control center via a CAN data bus. The control center is connected to the nitrogen injector and grouting machine of the nitrogen injection and grouting system via a PLC controller through the CAN data bus. A bundled tube support is installed on one side of a connecting roadway parallel to both sides of the coal face, with sensor bundled tubes laid on the support. The nitrogen injection and grouting system is installed on the other side of the roadway. The movable support of the injection nozzle, along with temperature, oxygen, and CO concentration sensors, is positioned at a certain distance from the coal face in the connecting roadway and goaf area, moving forward with the coal face. Sensor signals are transmitted to the control center. The movable support of the injection nozzle of the nitrogen injection and grouting system also moves forward with the coal face, covering the sensor area in the goaf. The control center determines the gas concentration and temperature for early warning based on the spontaneous combustion period of the coal seam, the width of the three spontaneous combustion zones in the goaf, and the spontaneous combustion indicator gas. When the sensor temperature and gas concentration measured in the goaf exceed the limits, an early warning signal is immediately issued, and the nitrogen injection mode is activated. When the gas containing the indicator gas for open flame is detected, the grouting mode is activated.

[0006] The plan further states that the specified distance is 13 to 20 meters.

[0007] A further aspect of the solution is that the bundled tube support is a movable support, with the sensor bundled tube extending from the movable support to the upper end of the goaf behind the coal mining face. The movable support moves forward with the coal mining face and maintains a certain distance from the coal mining face.

[0008] The solution further involves the following steps: The sensor signal is first connected to the PLC controller. The PLC controller converts the sensor's analog signal into a digital signal, which is then modulated by the CAN adapter and transmitted to the surface. The CAN adapter modulates the signal into a standard RS485 digital signal, which is then connected to the RS485 interface of the industrial control host computer in the control center. The digital signal is collected, stored, and displayed in the internal register of the industrial control computer. The collected digital signals are compared, analyzed, and processed in the control center. Various control signals are transmitted to the PLC controller, which communicates with the field equipment and issues execution commands to control the nitrogen injection machine and grouting machine.

[0009] The solution further states that the three self-ignition zones are a heat dissipation zone, an oxidation and heating zone, and a suffocation zone.

[0010] Heat dissipation zone: The heat dissipation zone in a goaf refers to an area with sufficient oxygen supply but no heat storage, or an area with sufficient oxygen supply but where the thickness of the floating coal (h) is less than the limit thickness (h). minFor areas without floating coal, the criterion is (C>18%)∪(10%≤C≤18%∩h). <h min );

[0011] Oxidation heating zone: The oxidation heating zone refers to the area with sufficient oxygen supply and good heat storage conditions, where only a portion of the heat generated by coal spontaneous combustion is carried away, and the remaining heat can sustain the continued oxidation and heating of the coal. The criterion for this zone is (10% ≤ C ≤ 18%) ∩ (h > h). min );

[0012] Asphyxiation zone: The asphyxiation zone refers to the area where the coal oxidation reaction slows down or stops because there is no oxygen supply to sustain the continued self-combustion and heating of the coal. The criterion for its determination is C < 10%.

[0013] Where: C is the oxygen concentration, and h is the thickness of the floating coal in the goaf.

[0014] The beneficial effects of this invention are: strong practicality, convenient operation, and safety. In the event of spontaneous combustion signs, it can remotely and quickly issue early warnings and take action to prevent fires; the invention has a fast reaction time, generally requiring only 5 minutes to complete, and all operations can be performed remotely, ensuring personnel safety and providing an automatic fire prevention and extinguishing control method for unmanned coal mining.

[0015] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the system structure of the present invention;

[0017] Figure 2 This is a schematic diagram of the system control circuit of the present invention. Detailed Implementation

[0018] An automatic fire prevention and extinguishing control method for underground coal mining is applicable to unmanned underground coal mining. It includes establishing an automatic fire prevention and extinguishing control system, such as... Figure 1 and Figure 2As shown: The automatic fire prevention and extinguishing control system includes a nitrogen injection system 1 and a grouting system 2, a control center 3, and temperature sensors 4, oxygen concentration sensors 5, and CO concentration sensors 6 that move continuously with the coal mining face. The nitrogen injection system 1, grouting system 2, and control center 3 are located on the ground, while the temperature sensors 4, oxygen concentration sensors 5, and CO concentration sensors 6 are located in the underground goaf area. The temperature sensors 4, oxygen concentration sensors 5, and CO concentration sensors 6 are connected to the control center via a CAN data bus 7. The control center 3 is connected to the nitrogen injection machine 101 and grouting machine 201 of the nitrogen injection and grouting system via a PLC controller 8 through the CAN data bus 7, and is also connected to an alarm system 9. Connecting roadways 11 are set parallel to each other on both sides of the coal mining working area 10 and the coal mining face. A bundled tube support 12 is set on one side of the connecting roadway, and sensor bundled tubes 13 are laid on the bundled tube support 12. A movable support 14 for the nozzles of the nitrogen injection and grouting system is set on the other side of the roadway. Temperature sensor 4, oxygen concentration sensor 5, and CO concentration sensor 6 are installed in the connecting roadway and goaf 15 at a certain distance from the coal face and move forward with the coal face 1001. The sensor signals are transmitted to the control center 3. The movable support 14 of the nitrogen injection and grouting system nozzles also moves forward with the coal face and covers the sensor installation area in the goaf. In order to ensure the quality of data transmission, a CAN adapter 701 and a relay station 702 are set in the CAN data bus 7 to connect the PLC controller 8 and the temperature sensor 4, oxygen concentration sensor 5, and CO concentration sensor 6. The control center 3 determines the gas concentration and temperature for early warning action based on the spontaneous combustion period of the coal seam (obtained from known research data), the width of the three spontaneous combustion zones in the goaf, and the spontaneous combustion indicator gas. When the sensor temperature and gas concentration measured from the goaf exceed the limit, an early warning signal is immediately issued and the nitrogen injection mode is activated. When the gas contains a gas indicating open flame, the grouting mode is activated. Of course, when a warning signal is received, the nitrogen injection mode will be activated after further analysis by engineering technicians and intelligent judgment modules to determine if nitrogen injection is necessary; when a gas indicating the presence of an open flame is found in the gas, the grouting mode will be activated after analysis by engineering technicians and intelligent judgment modules to determine if grouting is necessary.

[0019] Wherein: the certain distance is 13 to 20 meters. The bundle tube support 12 is a movable support. The movable support 12 and the movable support 14 of the nitrogen injection and grouting system nozzle are moved forward by the coal mining machine. The sensor bundle tube extends from the movable support to the upper end face of the goaf behind the coal mining face. The movable support moves with the coal mining face and maintains a certain distance from the coal mining face.

[0020] In this embodiment: The sensor signal is first connected to the PLC controller 8. The PLC controller 8 converts the sensor analog signal into a digital signal, modulates the signal via a CAN adapter, and transmits it to the well control center. The CAN adapter modulates the signal into a standard RS485 digital signal and connects it to the RS485 interface of the industrial control host computer in the control center. The digital signal is collected, stored, and displayed in the internal register of the industrial control computer. The collected digital signals are compared, analyzed, and processed in the control center. Various control signals are transmitted to the PLC controller and communicate with the field equipment to issue execution commands to control the nitrogen injection machine and grouting machine.

[0021] In this embodiment: the three spontaneous combustion zones are the heat dissipation zone, the oxidation and heating zone, and the asphyxiation zone; the goaf is divided into three zones, and spontaneous combustion of coal generally occurs in the spontaneous combustion zone; the division of the goaf into these three spontaneous combustion zones is an important basis for preventing spontaneous combustion in goafs. Reasonably determining the scope of the three spontaneous combustion zones in the goaf can enhance the targeting of fire prevention and extinguishing measures, improve the effectiveness of fire prevention and extinguishing projects, and effectively prevent spontaneous combustion accidents. This has significant practical implications for preventing spontaneous combustion in goafs and ensuring safe production at fully mechanized mining faces.

[0022] The theoretical basis for classifying spontaneous combustion zones into three zones is the coal-oxygen composite theory. This theory posits that spontaneous combustion of coal requires the simultaneous fulfillment of three conditions: 1) a tendency for spontaneous combustion and a fragmented, piled-up state; 2) a continuous oxygen supply through air leakage; and 3) good heat storage conditions. Analysis of the conditions for spontaneous combustion reveals that the first and third conditions are related to the thickness of the loose coal seam; only when the coal seam reaches a certain thickness can heat storage conditions be met. The second condition is related to oxygen concentration; only when the oxygen concentration reaches a certain value can the oxidation reaction of the loose coal be sustained. Therefore, the distribution of oxygen concentration and the distribution of loose coal thickness in the goaf can accurately reflect the spontaneous combustion environment and conditions of the loose coal in the goaf. Using these two indicators, the goaf can be scientifically divided into three zones of spontaneous combustion.

[0023] Spontaneous combustion is the result of a coal-oxygen complex reaction. When dividing the goaf into three zones for spontaneous combustion, it is necessary to consider not only the distribution of oxygen concentration in the goaf but also the distribution of coal—the material basis for spontaneous combustion. Only by combining the oxygen concentration C with the distribution of floating coal thickness h can the spontaneous combustion state of floating coal in a fully mechanized goaf be accurately reflected. There are three specific methods for this division.

[0024] Heat dissipation zone: The heat dissipation zone in a goaf refers to an area with sufficient oxygen supply but no heat storage, or an area with sufficient oxygen supply but where the thickness of the floating coal (h) is less than the limit thickness (h). min For areas without floating coal, the criterion is (C>18%)∪(10%≤C≤18%∩h). <h min );

[0025] Oxidation heating zone: The oxidation heating zone refers to the area with sufficient oxygen supply and good heat storage conditions, where only a portion of the heat generated by coal spontaneous combustion is carried away, and the remaining heat can sustain the continued oxidation and heating of the coal. The criterion for this zone is (10% ≤ C ≤ 18%) ∩ (h > h). min );

[0026] Asphyxiation zone: The asphyxiation zone refers to the area where the coal oxidation reaction slows down or stops because there is no oxygen supply to sustain the continued self-combustion and heating of the coal. The criterion for its determination is C < 10%.

[0027] Where: C is the oxygen concentration, h is the thickness of the floating coal in the goaf, and h min It is 100mm.

[0028] The above-described embodiment of the automatic fire prevention and extinguishing control method for underground mining is highly practical, convenient, and safe to operate. In the event of spontaneous combustion signs, it can remotely and quickly issue early warnings and take action to prevent fires. This method has a fast response time, generally requiring only 5 minutes to complete. All operations can be performed remotely, ensuring personnel safety and providing an automatic fire prevention and extinguishing control method for unmanned coal mining.

Claims

1. An automatic control method for fire prevention and extinguishing in underground mines, comprising establishing an automatic fire prevention and extinguishing control system, characterized in that, The automatic fire prevention and extinguishing control system includes a nitrogen injection and grouting system, a control center, and temperature sensors, oxygen concentration sensors, and CO concentration sensors that move continuously with the coal face. The temperature sensors, oxygen concentration sensors, and CO concentration sensors are connected to the control center via a CAN data bus. The control center is connected to the nitrogen injector and grouting machine of the nitrogen injection and grouting system via a PLC controller through the CAN data bus. In the connecting roadways parallel to both sides of the coal face, a bundled tube support is installed on one side of the roadway, with sensor bundled tubes laid on the support. A movable support for the nitrogen injection and grouting system nozzles is installed on the other side of the roadway. Temperature sensors, oxygen concentration sensors, and CO concentration sensors are also present. Gas concentration sensors and CO concentration sensors are installed in connecting roadways and goaf areas at a certain distance from the coal face and move forward with the coal face. The sensor signals are transmitted to the control center. The movable support of the nitrogen injection and grouting system nozzles also moves forward with the coal face and covers the sensor installation area in the goaf. The control center determines the gas concentration and temperature for early warning based on the spontaneous combustion period of the coal seam, the width of the three spontaneous combustion zones in the goaf, and the spontaneous combustion indicator gas. When the sensor temperature and gas concentration measured in the goaf exceed the limits, an early warning signal is immediately issued and the nitrogen injection mode is activated. When the gas contains a gas indicating open flame, the grouting mode is activated. The specified distance is 13 to 20 meters. The bundled tube support is a movable support. The sensor bundled tube extends from the movable support to the upper end of the goaf behind the coal mining face. The movable support moves with the forward movement of the coal mining face and maintains a certain distance from the coal mining face.

2. The automatic control method for downhole fire prevention and extinguishing according to claim 1, characterized in that, The sensor signals are first connected to the PLC controller. The PLC controller converts the sensor analog signals into digital signals, which are then modulated by the CAN adapter and transmitted to the surface. The CAN adapter modulates the signals into standard RS485 digital signals and connects them to the RS485 interface of the industrial control host computer in the control center. The digital signals are collected, stored, and displayed in the internal registers of the industrial control computer. The collected digital signals are compared, analyzed, and processed in the control center. Various control signals are transmitted to the PLC controller, which communicates with the field equipment and issues execution commands to control the nitrogen injection machine and grouting machine.

3. The automatic control method for downhole fire prevention and extinguishing according to claim 1, characterized in that, The three zones of spontaneous combustion are the heat dissipation zone, the oxidation and heating zone, and the asphyxiation zone. Heat dissipation zone: The heat dissipation zone in a goaf refers to an area with sufficient oxygen supply but no heat storage, or an area with sufficient oxygen supply but where the thickness of the floating coal (h) is less than the limit thickness (h). min For areas without floating coal, the criterion is (C>18%)∪(10%≤C≤18%∩h). <h min ); Oxidation heating zone: The oxidation heating zone refers to the area with sufficient oxygen supply and good heat storage conditions, where only a portion of the heat generated by coal spontaneous combustion is carried away, and the remaining heat can sustain the continued oxidation and heating of the coal. The criterion for this zone is (10% ≤ C ≤ 18%) ∩ (h > h). min ); Asphyxiation zone: The asphyxiation zone refers to the area where the coal oxidation reaction slows down or stops because there is no oxygen supply to sustain the continued self-combustion and heating of the coal. The criterion for its determination is C < 10%. Where: C is the oxygen concentration, and h is the thickness of the floating coal in the goaf.

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