Mine conveyor belt fire early warning index construction and early warning method

Abstract

The invention relates to the technical field of mine fire early warning, and provides a mine conveyor belt fire early warning index construction and early warning method, which comprises the following steps: verifying the feasibility of HCl gas as a symbolic gas for conveyor belt fire early warning through an energy spectrum test and a thermal decomposition experiment; a TG-DTG curve is obtained; establishing an early warning index and a multi-level early warning threshold value; constructing a system architecture and an interface; monitoring equipment is arranged; establishing data sharing and establishing a data sharing port; developing a monitoring data analysis module; drawing HCl gas concentration, CO gas concentration and conveyer belt temperature field graphs of the conveyer belt roadway; building a conveyor belt fire hazard dangerous area; and an alarm signal is sent to the outside through the audible and visual alarm and the linked controller connected with the audible and visual alarm is started. According to the scheme, the landmark gas detection has the characteristics of high sensitivity and regularity, so that the problem that early warning cannot be realized due to insensitivity of the existing mine fire early warning system is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of mine fire early warning, and in particular to a mine conveyor belt fire early warning indicator construction and early warning method. Background Art

[0002] Mine fire is one of the major natural disasters in coal mine production. Mine fire will burn a large amount of coal resources and equipment, produce a large amount of high-temperature smoke and toxic and harmful gases, and seriously endanger the lives of underground personnel. As the mine extends deeper, the length of the conveyor belt increases, and the threat of conveyor belt fire hazards continues to increase. Effective prevention is an important prerequisite for ensuring safe production in mines. Therefore, a fire early warning system based on signature gas detection is particularly important.

[0003] Most of the existing early warning systems for mine conveyor belt fires use CO as the signature gas, and the alarm concentration of the CO sensor is generally 24ppm. When a conveyor belt fire occurs, it takes a long time for the CO gas concentration to rise to this concentration. Belt conveyors are generally installed in tunnels with large air volumes. Affected by the dilution of the air volume, even if the conveyor belt has caught fire, only trace concentrations of CO gas may appear, resulting in the serious consequence that the carbon monoxide sensor cannot provide early warning in an accident. Summary of the invention

[0004] In order to solve the problems existing in the background technology, the present invention proposes a mine conveyor belt fire early warning indicator construction and warning method, and selects signature gas detection with high sensitivity and regularity to solve the problem that the existing mine fire warning system is insensitive and thus cannot achieve early warning. Through early warning, fire extinguishing measures can be taken in time to prevent the accident from expanding and reduce the impact on the overall safety of the mine.

[0005] To achieve the above object, the present invention adopts the following scheme, comprising the following steps:

[0006] Step 1: Construct early warning indicators for conveyor belts through experiments

[0007] Step 1.1 Select conveyor belts and coal from different locations in the mine as experimental samples;

[0008] Step 1.2: performing an energy spectrum test on the conveyor belt and coal of the experimental sample, and verifying the feasibility of HCl gas as a characteristic gas for early warning of conveyor belt fire based on the element composition and content of the experimental sample;

[0009] Step 1.3: Conducting a gas emission test on the conveyor belt of the experimental sample during the thermal decomposition process, measuring the absorbance integral of the infrared spectrum data of the conveyor belt, and then obtaining the FGP curve of the emitted gas to analyze the characteristic law of the emitted gas, and further verifying the feasibility of HCl gas as a characteristic gas for early warning of conveyor belt fire; Step 1.4: Conducting a combustion experiment of the conveyor belt and coal mixed experimental sample in an air atmosphere to obtain a TG-DTG curve;

[0010] Step 1.5: first, based on the thermal decomposition experiment, the temperature of the conveyor belt when HCl gas is initially detected is used as the early warning threshold, and then the combustion characteristics of the coal and conveyor belt mixed experimental sample are obtained based on the TG-DTG curve to establish a multi-level warning threshold;

[0011] Step 2: Build a conveyor belt fire early warning system

[0012] Step 2.1 build system architecture and interface;

[0013] Step 2.2: Deploy monitoring equipment above the conveyor belt and on the rollers for detecting HCl gas concentration, CO gas concentration and monitoring the temperature of the conveyor belt;

[0014] Step 2.3: Connecting the data acquisition module to the monitoring device to collect data on HCl gas concentration, CO gas concentration and conveyor belt temperature from the monitoring device in real time; establishing a data sharing port to realize data exchange and sharing with the sound and light alarm and linkage controller;

[0015] Step 2.4: Connect the developed monitoring data analysis module to the data acquisition module, automatically analyze and process the collected data, and extract key features;

[0016] Step 2.5: With the conveyor belt arranged along the conveying direction as the X-axis, time as the Y-axis, and the HCl gas concentration, CO gas concentration and conveyor belt temperature as the Z-axis, a spatial rectangular coordinate system is established to draw the HCl gas concentration, CO gas concentration and conveyor belt temperature field diagram of the conveyor belt lane;

[0017] Step 2.6: In the field map, the area where the conveyor belt temperature is greater than the early warning threshold or the area where the HCl gas concentration is greater than the HCl gas concentration value corresponding to the early warning threshold is defined as a conveyor belt fire hazard area, and the conveyor belt fire hazard area is divided into different levels according to different warning thresholds; Step 2.7: When a fire hazard area appears in the field map, an alarm signal is sent to the outside world through the sound and light alarm and the connected linkage controller is started.

[0018] Furthermore, in the experimental samples, the conveyor belt adopts a rubber surface solid core flame retardant conveyor belt PVG sample.

[0019] Furthermore, in step 1.2, when the experimental samples were subjected to energy spectrum testing, the conveyor belt used PVG block samples and the coal used coal powder samples; the energy spectrum test showed that the coal was a functional group composed of two elements, C and O, and the signal intensity peak of the Cl element in the conveyor belt PVG was more obvious.

[0020] Furthermore, in the step 1.3, the thermal decomposition experiment adopts a heating rate of 10K / min and a temperature range of 30°C to 800°C. The escaped gas test adopts a thermogravimetric-infrared analyzer. The characteristic law of the escaped gas is that HCl gas begins to be generated when the thermal decomposition temperature is about 170°C, and the main gas product before the thermal decomposition temperature is HCl. When the thermal decomposition temperature is 270°C to 290°C, the amount of HCl gas generated is the largest, while CO, CO 2 The maximum escape corresponds to a temperature exceeding 460°C.

[0021] Furthermore, the combustion experiment in step 1.4 includes three stages: the starting stage when the conveyor belt temperature is 30°C to 211.58°C, HCl gas is generated; the decomposition and combustion stage when the conveyor belt temperature is 211.58°C to 633.43°C, wherein the conveyor belt temperature is 286.51°C, a large amount of HCl gas is generated, the peak temperature of the second area is 438.31°C, and a large amount of CO gas is generated while HCl gas is generated; the burnout stage when the conveyor belt temperature exceeds 633.43°C, and the generated gas is negligible.

[0022] Further, in step 1.5, the conveyor belt temperature when the HCl gas is initially detected is 170° C., and the multi-level warning threshold includes a first-level warning threshold, a second-level warning threshold and a third-level warning threshold, including a first-level warning threshold range of greater than or equal to 250° C. and less than 350° C., a second-level warning temperature preset threshold range of greater than or equal to 350° C. and less than 500° C., and a third-level warning temperature preset threshold range of greater than or equal to 500° C.

[0023] Furthermore, in step 2.1, the system architecture and interface include system functions and performance requirements determined with the user, a system outline design diagram and a user interface design diagram.

[0024] Furthermore, in step 2.4, the key features include the changing trend of gas concentration and the changing pattern of temperature.

[0025] The beneficial effects of the present invention are as follows: the present solution verifies the feasibility of HCl gas as a characteristic gas for early warning of conveyor belt fires through energy spectrum testing and thermal decomposition experiments, and constructs an early warning threshold using the HCl gas generated by the conveyor belt as the dominant factor, and then establishes a multi-level warning threshold based on the TG-DTG curve to obtain the law of change of HCl gas overflow with temperature. This hierarchical warning method can help relevant personnel better judge the severity of fire risks, rationally allocate resources, and take effective countermeasures, thereby improving the safety of the conveyor belt system and reducing the occurrence and losses of fire accidents. On the other hand, the present solution constructs an early warning system for conveyor belt fires based on early warning indicators of conveyor belts, which can detect signs of fire in a timely manner, buy precious time for personnel evacuation, and reduce the risk of casualties. Moreover, through early warning, fire-fighting measures can be taken in a timely manner to reduce property losses, prevent accidents from expanding, and reduce the impact on the overall safety of mines. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a flow chart of the present invention;

[0027] Figure 2 is the surface element signal intensity of the coal powder experimental sample of the embodiment of the present invention;

[0028] Figure 3 is the surface element signal intensity of the PVG bulk experimental sample of the embodiment of the present invention;

[0029] Figure 4 This is a FGP curve diagram of HCl gas released during the pyrolysis of PVG conveyor belt according to an embodiment of the present invention;

[0030] Figure 5 This is a FGP curve diagram of CO gas released during the pyrolysis of PVG conveyor belt according to an embodiment of the present invention;

[0031] Figure 6 This is a schematic diagram of the arrangement of the inspection and monitoring equipment according to an embodiment of the present invention;

[0032] Figure 7 It is a TG-DTG curve diagram of the combustion experiment of the embodiment of the present invention.

[0033] Numbers in the figure: 1. Monitoring equipment; 2. Conveyor belt; 3. Coal; 4. Roller. DETAILED DESCRIPTION

[0034] In order to make the present invention clearer and more understandable, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the given embodiment is only one implementation method and does not represent all embodiments.

[0035] Embodiment 1

[0036] Combination Figure 1 This embodiment provides a method for constructing an early warning indicator for a conveyor belt fire in a mine and a warning method, comprising the following steps:

[0037] Step 1 constructs early warning indicators for conveyor belt 2 through experiments.

[0038] Step 1.1 In order to ensure the accuracy of the experiment, conveyor belts 2 and coal 3 from different locations in the mine are selected as experimental samples. In the experimental samples, conveyor belt 2 adopts a rubber-surfaced solid-core flame-retardant conveyor belt 2 PVG sample.

[0039] Step 1.2 performs spectrum test on the conveyor belt 2 and coal 3 of the experimental sample, and verifies the feasibility of HCl gas as a characteristic gas for early warning of fire on the conveyor belt 2 from the element composition and content of the experimental sample. When the experimental sample is subjected to spectrum test, the conveyor belt 2 uses PVG block sample and the coal 3 uses coal 3 powder sample; the spectrum test shows that: Figure 2 It can be seen that the coal 3 is a functional group composed of two elements, C and O. Figure 3 It can be seen that the signal intensity peak of the Cl element in the conveyor belt 2 PVG is relatively obvious. Therefore, from the element composition and content, it can be proved that HCl gas can be used as a signature gas for early warning of the conveyor belt 2 fire.

[0040] Step 1.3: Conduct a gas emission test on the conveyor belt 2 of the experimental sample during the thermal decomposition process, measure the absorbance integral of the infrared spectrum data of the conveyor belt 2, and then obtain the FGP curve of the emitted gas, such as Figure 4 , Figure 5 , in order to analyze the characteristics of the escaping gas and further verify the feasibility of HCl gas as a signature gas for early warning of conveyor belt 2 fire.

[0041] The thermal decomposition experiment adopts a heating rate of 10K / min and a temperature range of 30℃~800℃. The escaped gas test adopts a thermogravimetric-infrared analyzer. Through the thermal decomposition experiment, it can be concluded that the characteristic law of the escaped gas is: HCl gas begins to be generated when the thermal decomposition temperature is about 170℃, and the main gas product before the thermal decomposition temperature is HCl. When the thermal decomposition temperature is 270℃~290℃, the amount of HCl gas generated is the largest, while CO, CO 2 The maximum escape temperature is over 460°C. The main products before 280°C are HCl, CO, and CO 2 The amount of gas generated is relatively small. As the temperature rises further, the conveyor belt 2 will pyrolyze and produce a large amount of CO and CO 2 Therefore, HCl gas can be regarded as the characteristic gas of conveyor belt 2 fire.

[0042] Step 1.4: Carry out a combustion test of the mixed experimental sample of conveyor belt 2 and coal 3 in an air atmosphere to obtain a TG-DTG curve, such as Figure 7 ;

[0043] The combustion process of the experimental sample of mixing coal 3 with conveyor belt 2 can be divided into three stages: preparation stage, decomposition and combustion stage, and burnout stage.

[0044] (1) Preparation

[0045] At the beginning of the experiment, the temperature of the conveyor belt 2 was from 30°C to 211.58°C, which was the preparation stage. During this stage, the weight loss of the conveyor belt 2 was only 1.34%, which was small, indicating that the damage it suffered was relatively light, probably just slight wear on the surface or loss of a small amount of material. At this time, the performance and service life of the conveyor belt 2 may be less affected, and HCl gas began to be generated at this time.

[0046] (2) Decomposition and combustion stage

[0047] The temperature of conveyor belt 2 is 211.58℃ to 633.43℃, which is the decomposition and combustion stage. During this stage, conveyor belt 2 loses weight by 50.84%, indicating that the damage to conveyor belt 2 is gradually increasing. A higher weight loss rate may mean that the structure of conveyor belt 2 has been severely damaged, the strength and wear resistance of the material have decreased, and safety hazards have emerged. According to the DTG curve of this stage, it can be divided into two areas with faster weight loss rates. The peak temperature of the first area is 286.51℃, the weight loss rate is 6.15% / min, and a large amount of HCl gas is produced. The peak temperature of the second area is 438.31℃, the weight loss rate is 1.32% / min, and HCl gas and a large amount of CO gas are also produced.

[0048] (3) Burnout stage

[0049] The temperature of conveyor belt 2 exceeded 633.43℃, which was the burnout stage. According to the TG curve of this stage, the mass of the mixed sample decreased slightly or remained basically unchanged, and the final combustion residue reached 47.82%, and basically no gas was released.

[0050] Step 1.5 first uses the temperature of the conveyor belt 2 when HCl gas is initially detected as an early warning threshold based on the combustion experiment, and then obtains the combustion characteristics of the coal and conveyor belt mixed experimental sample based on the TG-DTG curve to establish a multi-level warning threshold. Based on step 1.3, the temperature of the conveyor belt 2 when HCl gas is initially detected is 170°C. In the experiment, an HCl sensor is used, and the alarm concentration is set to a trace concentration. When HCl gas is detected, the temperature of the conveyor belt 2 has reached 170°C, so it can be considered that the conveyor belt 2 is about to or has entered the bond breaking and cracking stage, so the temperature of the conveyor belt 2 is 170°C as the early warning threshold.

[0051] Based on the TG-DTG curve rule in step 1.4, the multi-level warning threshold is set to a three-level warning threshold, including a first-level warning threshold range of greater than or equal to 250°C and less than 350°C, a second-level warning temperature preset threshold range of greater than or equal to 350°C and less than 500°C, and a third-level warning temperature preset threshold range of greater than or equal to 500°C.

[0052] It should be understood that in the process of constructing early warning indicators for conveyor belt 2 through experiments, especially in the thermal decomposition experiment in step 1.3 and the combustion experiment in step 1.4, it is necessary to analyze the characteristics and influencing factors of each stage by combining the stage characteristics of gas generation with the integral method to calculate the oxidation kinetics and derive the reaction mechanism function. The specific algorithm formula is as follows:

[0053]

[0054] In the formula, α is the conversion rate of the material during oxidation and decomposition, in %; t is the time of oxidation and decomposition of the material, in s; A is the pre-exponential factor of the reaction, in s -1 ; E is the apparent activation energy, unit is J / mol; R is the thermodynamic gas constant, unit is J / (mol·K); T is the temperature, unit is K; f(α) is the reaction kinetic mechanism function.

[0055]

[0056] Where W 0 is the initial mass of the sample, in g; W t is the mass of the sample at time t, in g; W t is the mass of the sample at the end time, in g.

[0057] f(α) can be defined as: f(α) = (1-α) n

[0058] Combining the above formulas, we can get:

[0059] Integrating both sides, we get:

[0060] Where, T 0 is the initial temperature in K.

[0061] When the first-order chemical kinetic model is used, the correlation coefficient is the largest, and the oxidation reaction between coal and conveyor belt is considered to be a first-order chemical reaction, that is, n = 1. The approximate solution is obtained using the Coats-Redfern integral formula:

[0062]

[0063] make

[0064] The above formula is transformed into: y = a + bx

[0065] Activation energy is an important indicator to characterize the intensity of material combustion. By using the formula for statistical analysis and data fitting, we can get the fitting coefficient and straight line. The slope of the straight line is b and the intercept is a. The activation energy E under the conversion rate condition can be obtained from the slope of the straight line, and the pre-exponential factor A corresponding to the activation energy E can be obtained from the intercept.

[0066] Step 2: Constructing a Conveyor Belt 2 Fire Early Warning System

[0067] Step 2.1 builds the system architecture and interface; the system architecture and interface includes the system functions and performance requirements determined with the user, the system outline design diagram and the user interface design diagram.

[0068] Step 2.2 Figure 6 , a monitoring device 1 for detecting HCl gas concentration, CO gas concentration and monitoring the temperature of the conveyor belt 2 is arranged above the conveyor belt 2 and on the roller 4; the HCl gas concentration and CO gas concentration can be detected by a combustible gas sensor, and the temperature of the conveyor belt 2 can be detected by an infrared temperature sensor. Through the characteristics of the combustion process of the experimental sample of the mixture of coal 3 and the conveyor belt 2, it can be seen that the CO gas concentration in the later stage of the fire is also an object that needs to be monitored, which is indispensable for grasping the combustion degree of the conveyor belt and establishing a multi-level early warning.

[0069] Step 2.3: Develop a data acquisition module connected to the monitoring device 1 to collect data on HCl gas concentration, CO gas concentration and conveyor belt 2 temperature from the monitoring device 1 in real time; establish a data sharing port to realize data exchange and sharing with the sound and light alarm and linkage controller. Through timely data exchange and sharing, when the fire early warning system detects an abnormal situation, it can quickly transmit information to the sound and light alarm and linkage controller. The sound and light alarm can immediately send out an alarm signal to remind people to evacuate, and the linkage controller can automatically start related fire-fighting equipment, such as fire extinguishing system, smoke exhaust system, etc., thereby greatly improving the speed of fire response and gaining precious time to reduce the losses caused by the fire. On the other hand, data sharing enables various fire-fighting equipment to work together to form an organic whole. This can more effectively play the role of each device and improve the prevention and control capabilities of the entire fire-fighting system. For example, the accurate information provided by the early warning system can help the linkage controller more accurately control the start-up timing and operating parameters of the fire-fighting equipment and improve the effect of fire extinguishing and smoke exhaust.

[0070] Step 2.4 develops a monitoring data analysis module connected to the data acquisition module to automatically analyze and process the collected data and extract key features, including the changing trend of gas concentration and the changing pattern of temperature. By analyzing these key features, we can better understand the information contained in the monitoring data, provide strong support for decision-making, and timely discover potential problems and abnormal situations.

[0071] Step 2.5 takes the conveyor belt 2 set along the conveying direction as the X-axis, time as the Y-axis, and the HCl gas concentration, CO gas concentration and the temperature of the conveyor belt 2 as the Z-axis, respectively, to establish a spatial rectangular coordinate system, and draw the HCl gas concentration, CO gas concentration and conveyor belt 2 temperature field map of the conveyor belt 2 lane. The field map can use professional drawing software, such as Matlab, Origin, Python drawing library (such as matplotlib), etc., and color mapping can be added to the field map as needed to indicate the concentration or temperature.

[0072] Step 2.6: In the field map, the area where the conveyor belt temperature is greater than the early warning threshold or the area where the HCl gas concentration is greater than the HCl gas concentration value corresponding to the early warning threshold is defined as the conveyor belt fire hazard area, and the conveyor belt fire hazard area is divided into different levels according to different warning thresholds. Preferably, the different levels can be divided by color to make it more eye-catching.

[0073] When the monitored parameter value reaches the early warning threshold, it means that there may be a potential fire risk, which requires attention and appropriate preventive measures, such as strengthening inspections and checking for hidden dangers. When the parameter value exceeds a higher level of warning threshold, it indicates that the fire risk has further increased and more urgent measures may need to be taken, such as activating emergency plans and evacuating personnel. This hierarchical warning method can help relevant personnel better judge the severity of fire risks, rationally allocate resources, and take effective response measures, thereby improving the safety of the conveyor belt 2 system and reducing the occurrence and losses of fire accidents.

[0074] Step 2.7: When a fire hazard area appears in the on-site map, an alarm signal is sent to the outside world through the sound and light alarm and the connected linkage controller is activated to take relevant measures.

[0075] The specific embodiments of the present invention are described in detail above with reference to the drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions and variations of these embodiments are made without departing from the principles and spirit of the present invention, and still fall within the scope of protection of the present invention.

Claims

1. A mine conveyor belt fire early warning indicator construction and early warning method, characterized in that: The steps include: Step 1: Construct early warning indicators for conveyor belts through experiments Step 1.1 Select conveyor belts and coal from different locations in the mine as experimental samples; Step 1.2: performing an energy spectrum test on the conveyor belt and coal of the experimental sample, and verifying the feasibility of HCl gas as a characteristic gas for early warning of conveyor belt fire based on the element composition and content of the experimental sample; Step 1.3: Conducting a gas emission test on the conveyor belt of the experimental sample during the thermal decomposition process, measuring the absorbance integral of the infrared spectrum data of the conveyor belt, and then obtaining the FGP curve of the emitted gas to analyze the characteristic law of the emitted gas, and further verifying the feasibility of HCl gas as a characteristic gas for early warning of conveyor belt fire; Step 1.4: Conducting a combustion experiment of the conveyor belt and coal mixed experimental sample in an air atmosphere to obtain a TG-DTG curve; Step 1.5: first, based on the thermal decomposition experiment, the temperature of the conveyor belt when HCl gas is initially detected is used as the early warning threshold, and then the combustion characteristics of the coal and conveyor belt mixed experimental sample are obtained based on the TG-DTG curve to establish a multi-level warning threshold; Step 2: Build a conveyor belt fire early warning system Step 2.1 build system architecture and interface; Step 2.2: Deploy monitoring equipment above the conveyor belt and on the rollers for detecting HCl gas concentration, CO gas concentration and monitoring the temperature of the conveyor belt; Step 2.3: Connecting the data acquisition module to the monitoring device to collect data on HCl gas concentration, CO gas concentration and conveyor belt temperature from the monitoring device in real time; establishing a data sharing port to realize data exchange and sharing with the sound and light alarm and linkage controller; Step 2.4: Connect the developed monitoring data analysis module to the data acquisition module, automatically analyze and process the collected data, and extract key features; Step 2.5: With the conveyor belt arranged along the conveying direction as the X-axis, time as the Y-axis, and the HCl gas concentration, CO gas concentration and conveyor belt temperature as the Z-axis, a spatial rectangular coordinate system is established to draw the HCl gas concentration, CO gas concentration and conveyor belt temperature field diagram of the conveyor belt lane; Step 2.6: In the field map, the area where the conveyor belt temperature is greater than the early warning threshold or the area where the HCl gas concentration is greater than the HCl gas concentration value corresponding to the early warning threshold is defined as a conveyor belt fire hazard area, and the conveyor belt fire hazard area is divided into different levels according to different warning thresholds; Step 2.7: When a fire hazard area appears in the field map, an alarm signal is sent to the outside world through the sound and light alarm and the connected linkage controller is started.

2. The method for constructing early warning indicators and early warning methods for conveyor belt fires in mines according to claim 1 is characterized by: In the experimental samples, the conveyor belt adopts a rubber surface solid core flame retardant conveyor belt PVG sample.

3. The method for constructing early warning indicators and early warning methods for conveyor belt fires in mines according to claim 2 is characterized by: In step 1.2, when the experimental samples are subjected to energy spectrum testing, the conveyor belt uses PVG block samples and the coal uses coal powder samples; the energy spectrum test shows that the coal is a functional group composed of two elements, C and O, and the signal intensity peak of the Cl element in the conveyor belt PVG is obvious.

4. The method for constructing early warning indicators and early warning methods for conveyor belt fires in mines according to claim 2 is characterized by: In the step 1.3, the thermal decomposition experiment adopts a heating rate of 10K / min and a temperature range of 30°C to 800°C. The evolved gas test adopts a thermogravimetric-infrared analyzer. The characteristic law of the evolved gas is as follows: HCl gas begins to be generated when the thermal decomposition temperature is about 170°C, the main gas product before the thermal decomposition temperature is HCl is HCl, the thermal decomposition temperature is 270°C to 290°C, and the maximum HCl gas generation corresponds to a temperature of more than 460°C.

5. The method for constructing early warning indicators and early warning methods for conveyor belt fires in mines according to claim 2 is characterized by: The combustion experiment in step 1.4 includes three stages: the starting stage when the conveyor belt temperature is 30°C to 211.58°C, HCl gas is generated; the decomposition and combustion stage when the conveyor belt temperature is 211.58°C to 633.43°C, wherein the conveyor belt temperature is 286.51°C, a large amount of HCl gas is generated, and the conveyor belt temperature is 438.31°C, generating HCl gas and a large amount of CO gas; the burnout stage when the conveyor belt temperature exceeds 633.43°C, and the generated gas is negligible.

6. The method for constructing early warning indicators and early warning methods for conveyor belt fires in mines according to claim 2, characterized in that: In step 1.5, the conveyor belt temperature when HCl gas is initially detected is 170° C., and the multi-level warning threshold includes a first-level warning threshold, a second-level warning threshold and a third-level warning threshold, including a first-level warning threshold range of greater than or equal to 250° C. and less than 350° C., a second-level warning temperature preset threshold range of greater than or equal to 350° C. and less than 500° C., and a third-level warning temperature preset threshold range of greater than or equal to 500° C.

7. A mine conveyor belt fire early warning indicator construction and early warning method according to claim 1, Features: In step 2.1, the system architecture and interface include the system functions and performance requirements determined with the user, the system outline design diagram and the user interface design diagram.

8. The method for constructing early warning indicators and early warning methods for conveyor belt fires in mines according to claim 1 is characterized by: In step 2.4, the key features include the changing trend of gas concentration and the changing pattern of temperature.

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