A method for assessing the ignition hazard of materials in coal mine explosion environments

Abstract

The present invention discloses a method for assessing the ignition hazard of materials in a coal mine explosion environment, comprising the following steps: (1) analyzing factors affecting the explosion process of the material to be tested in the environment of the coal mine, (2) conducting a pipeline explosion experiment to determine the temperature distribution, influence range and duration of the explosion flame; (3) constructing a pipeline explosion numerical simulation model according to the experimental values ​​and constructing a numerical simulation model of the actual mine size based on the model, analyzing the corresponding relationship between the explosion flame temperature and duration at the position of the material to be tested; (4) testing the ignition temperature and time of the material to be tested; (5) finding the working conditions and parameter values ​​under which the explosion flame temperature and duration meet the ignition conditions of the material to be tested; and (6) calculating the probability of the material to be tested being ignited, and using the probability to assess the ignition hazard of the material to be tested in an actual explosion environment, thereby achieving a scientific assessment of the ignition hazard of the material under different explosion conditions.

Description

Technical Field

[0001] The invention relates to the field of material ignition hazard assessment, and in particular to a material ignition hazard assessment method for use in a coal mine explosion environment. Background Art

[0002] Gas / coal dust explosion accidents are one of the most serious disasters faced by coal mine safety production. The high temperature, shock wave and toxic gases generated by gas / coal dust explosions pose a major threat to operators. Coal mine gas explosion accidents show that the explosion flame ignites underground combustibles during the propagation process, causing serious fire accidents and expanding the scope of the disaster. Therefore, in order to reduce the risk of subsequent multiple explosions / fire accidents caused by explosion accidents, the danger of combustibles in coal mines being ignited in an explosive environment should be scientifically evaluated and corresponding prevention and control measures should be formulated based on the evaluation results. The current devices and methods for testing the combustion performance of materials are mainly cone calorimeters, glow wire tests, needle flame combustion tests, and horizontal and vertical combustion test methods. Most of these traditional methods are simple to operate and highly practical, and can accurately evaluate the combustion / flame retardant properties of materials under general environments. However, there are still some shortcomings when it comes to assessing the ignition hazard of materials in complex explosion environments in coal mines. For example, the burning area of ​​the glow-wire test is small and the heating time is long, making it difficult to accurately determine the ignition hazard of the material under test under the conditions of instantaneous temperature rise in the explosion. The test results of the needle flame combustion test and the horizontal and vertical combustion test cannot be quantified, and the ignition temperature and ignition time of the material under test cannot be accurately determined in the explosion environment. At the same time, the traditional test method can only determine the combustion / flame retardant properties of the material under test under fixed conditions, while the temperature and duration of the explosion flame under different working conditions vary greatly, and it is difficult for the traditional method to carry out targeted measurements according to different working conditions in the actual application environment. Therefore, it is necessary to propose a method for quantitatively assessing the ignition hazard of materials under coal mine explosion environments based on the characteristics of coal mine explosions. Summary of the invention

[0003] In view of the above-mentioned technical deficiencies, the purpose of the present invention is to provide a method for assessing the ignition hazard of materials in coal mine explosion environments, which can achieve a scientific assessment of the ignition hazard of materials under different explosion conditions.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] The present invention provides a method for assessing the ignition hazard of materials in a coal mine explosion environment, comprising the following steps:

[0006] (1) Analyze the environment of the material to be tested in the coal mine, determine the variation range of the type and concentration parameters of the combustible gas or dust in the mine, the variation range of the position parameters of the material to be tested, and the variation range of the blocking state parameters of obstacles along the way;

[0007] (2) Conducting a combustible gas or dust pipeline explosion experiment according to the variation range of each parameter determined in step (1) to determine the temperature distribution, impact range and duration of the explosion flame under different parameters;

[0008] (3) constructing a numerical simulation model of the pipeline explosion experiment based on the experimental data of step (2), and constructing an actual size numerical simulation model based on the numerical simulation model and taking the actual mine size parameters as a reference, determining the explosion flame temperature distribution, impact range and duration under different parameters in the actual size numerical simulation model, and analyzing the corresponding relationship between the explosion flame temperature and duration at the position of the material to be tested;

[0009] (4) Use the material ignition condition test device to test the ignition temperature and time of the material to be tested, and record the temperature range in which the material to be tested can be ignited under instantaneous heating conditions and the corresponding shortest heating time;

[0010] (5) Compare the explosion flame temperature and duration at the position of the material to be tested obtained in step (3) with the ignition temperature and the shortest heating time of the material to be tested obtained in step (4), and find out the parameter values ​​that make the explosion flame temperature and duration meet the ignition conditions of the material to be tested;

[0011] (6) Calculate the probability of the test material being ignited based on the parameters determined in steps (1) and (5), and use this probability to assess the risk of the test material being ignited in an actual explosion environment.

[0012] Preferably, the combustible gas is gas, and the combustible dust is coal dust.

[0013] Preferably, the length of the experimental pipeline for the pipeline explosion experiment in step (2) is 3 m, and the cross-sectional area of ​​the pipeline is 0.2×0.2 m 2 .

[0014] Preferably, the material to be tested includes coal, wood, and a flame-retardant conveyor belt.

[0015] Preferably, the probability of ignition of the material to be tested is calculated in step (6) using the following calculation formula:

[0016] ;

[0017] Where: q ij is the probability of the i parameter causing the ignition event under the j condition, m is the total number of conditions, and n is the number of parameters.

[0018] The beneficial effects of the present invention are:

[0019] The present invention utilizes a material ignition condition testing device to quantitatively determine the ignition condition of the material to be tested. By comparing with the explosion flame propagation law obtained by experiments and simulations, the dangerous working conditions and parameter values ​​that make the explosion flame temperature and duration meet the ignition condition of the material to be tested can be found, providing theoretical guidance for the development of coal mine explosion / fire prevention and control work; based on the found dangerous working conditions and parameter values, by calculating their occurrence probability, the risk of ignition of the material to be tested in an actual explosion environment can be scientifically evaluated. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 The present invention is a flow chart of the material ignition hazard assessment method.

[0022] Figure 2 It is a schematic diagram of the explosion experiment pipeline system of the present invention.

[0023] Figure 3 It is a schematic diagram of the coal sample ignition condition testing device of the present invention.

[0024] Figure 4 A schematic diagram of data comparison provided by an embodiment of the present invention.

[0025] Among them: 2-1, explosion pipeline; 2-2, high-temperature thermocouple; 2-3, signal conditioning chassis; 2-4, high-energy igniter; 2-5, control host; 2-6, high-speed camera; 2-7, premixing chamber; 2-8, vacuum pump; 3-1, control host 2; 3-2, high-speed camera 2; 3-3, signal conditioning chassis 2; 3-4, controller 2; 3-5, motor; 3-6, sliding guide rail; 3-7, sliding clamp; 3-8, coal sample; 3-9, high-temperature thermocouple 2; 3-10, high-temperature heating furnace; 3-11, high-temperature heat conduction plate. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] like Figures 1 to 4As shown, this embodiment provides a method for assessing the ignition hazard of materials in a coal mine explosion environment, comprising the following steps:

[0028] Step 1: Analyze the environment of the material to be tested in the coal mine, and obtain the range of variation of the type and concentration parameters of the combustible gas / dust, the range of variation of the material position parameters, and the range of variation of the blocking state parameters of the obstacles along the way, wherein the blocking state parameters of the obstacles along the way include the type parameters, position parameters, height parameters, length parameters, and shape parameters of the obstacles along the way;

[0029] Step 2: Design the pipeline explosion test of combustible gas / dust in step 1, such as Figure 2 As shown, the length of the explosion pipeline 2-1 in this embodiment experiment is 3m, and the cross-sectional area is 0.2×0.2m 2 , a high-energy igniter 2-4 is arranged in the explosion pipeline 2-1. Before the explosion experiment begins, a methane-air premixed gas of the required concentration for the experiment is configured in the premixed gas chamber 2-7. The explosion pipeline 2-1 is evacuated to a vacuum by a vacuum pump 2-8. The gas in the premixed gas chamber 2-7 is transported to the explosion pipeline 2-1 through a delivery pipeline. A solenoid valve is arranged on the delivery pipeline. The temperature, duration and propagation range of the explosion flame during the explosion experiment are recorded by a high-temperature thermocouple 2-2 and a high-speed camera 2-6. The high-temperature thermocouple 2-2 is connected to a signal conditioning chassis 2-3. The signal conditioning chassis 2-3, the high-speed camera 2-6, the high-energy igniter 2-4, the vacuum pump 2-8, the solenoid valve and the control host 2-5 are electrically connected. The influence of the changes in each parameter in step one on the propagation law of the explosion flame is studied;

[0030] Step 3: Construct a numerical simulation model with the same experimental pipeline size as in step 2, perform simulation according to the same working conditions as in step 2, and correct the model parameters according to the experimental data obtained in step 2 so that the simulation values ​​fit the experimental values. Then, construct an actual numerical simulation model of the actual mine goaf size, study the temperature distribution, impact range and duration of the explosion flame under the changes of the combustible gas / dust type parameters and concentration parameters, material location parameters and obstacle blocking state parameters along the way, and analyze the explosion flame temperature and duration at the location of the material to be tested;

[0031] Step 4: Set up the material ignition condition test device, such as Figure 3As shown, the high-speed camera 2 3-2, the signal conditioning box 2 3-3 and the controller 2 3-4 are electrically connected to the control host 2 3-1, the motor 3-5 and the high-temperature thermocouple 2 3-9 are electrically connected to the controller 2 3-4 and the signal conditioning box 2 3-3 respectively. Before the test starts, the coal sample 3-8 is fixed on the sliding clamp 3-7, the sliding clamp 3-7 is moved to the top of the sliding guide rail 3-6, the high-temperature heating furnace 3-10 is started and the heating temperature is set, and the moving time, moving distance and other instructions of the sliding clamp 3-7 are preset in the control host 2 3-1 according to the test requirements. After the test starts, the controller 2 3-4 controls the motor 3-5 to operate according to the preset instructions of the control host 2 3-1, the sliding guide rail 3-6 is equipped with a belt and a motor 3-5 for driving the belt, the sliding clamp 3-7 is fixed on the belt, and the motor 3-5 drives the belt to drive the sliding clamp 3-7 to move on the sliding guide rail 3-6 The contact time between the coal sample 3-8 and the high-temperature heating plate 3-11 above the high-temperature heating furnace 3-10 meets the test requirements. During this process, the high-speed camera 3-2 and the high-temperature thermocouple 3-9 continuously record the combustion conditions and temperature changes before and after the contact between the coal sample 3-8 and the high-temperature heating plate 3-11. The temperature data obtained by the high-temperature thermocouple 3-9 is transmitted to the control host 3-1 through the signal conditioning chassis 3-3. The shortest heating time for the material to be tested to be ignited at different heating temperatures is measured, that is, the ignition condition of the material to be tested in an explosive environment. The preset instructions used by the control host 3-1 of this embodiment adopt instructions well known to those skilled in the art. The belt is installed on the sliding guide rail through a pulley, and the pulley is driven by the motor 3-5. The connection between the belt, the pulley, the motor, and the sliding guide rail adopts the existing method well known to those skilled in the art, which will not be described in detail here.

[0032] Step 5: Using the explosion flame data in step 3, the simulated explosion flame temperature, duration, and the ignition temperature range and shortest heating time are plotted in the same graph. In this embodiment, the explosion flame data under the condition of 9.5% methane concentration is taken as an example, and the graph is plotted as follows: Figure 4 As shown in the figure, if the temperature and duration of the explosion flame meet the ignition conditions of the material to be tested, it exists Figure 4 In the shaded area a, the working condition is considered to be a dangerous working condition and the probability of occurrence is P (1) = q1q2…q i , where q i It refers to the probability of the value of parameter i under the working condition. Similarly, the probability P(j) of other dangerous working conditions can be obtained. Different parameter values ​​in this embodiment correspond to different working conditions.

[0033] Step 6: Calculate the probability P(T) of the material to be tested being ignited in an actual explosion environment, that is, the sum of the probabilities P(j) of the ignition hazard conditions, so as to evaluate the hazard of the material to be tested being ignited in an actual explosion environment. ;

[0034] Where: q ij is the probability of the i parameter causing the ignition event under the j condition, m is the total number of conditions, and n is the number of parameters.

[0035] The explosion pipeline 2-1, high-temperature thermocouple 2-2, signal conditioning chassis 2-3, high-energy igniter 2-4, control host 2-5, high-speed camera 2-6, premixing chamber 2-7, vacuum pump 2-8, control host 2 3-1, high-speed camera 2 3-2, signal conditioning chassis 2 3-3, controller 2 3-4, motor 3-5, belt, sliding guide 3-6, sliding clamp 3-7, coal sample 3-8, high-temperature thermocouple 2 3-9, high-temperature heating furnace 3-10, high-temperature heat conduction plate 3-11, belt, and pulley of this embodiment adopt existing products or structures well known to those skilled in the art, and are connected to each other in existing ways well known to those skilled in the art, and will not be described in detail here.

[0036] This embodiment obtains the explosion flame temperature range and duration of different parameters in the actual environment through experiments and simulations, and uses a material ignition condition test device to determine the conditions for the test material to be ignited in the explosion environment. By comparing the two, the dangerous working conditions and parameter values ​​that make the explosion flame temperature and duration meet the ignition conditions of the test material are found, and based on this, the probability of the event that the test material is ignited is calculated, and then the danger of the test material being ignited in the actual explosion environment is evaluated; this embodiment uses a material ignition condition test device, an explosion test pipeline system and numerical simulation to quantitatively determine the dangerous working conditions and parameter values ​​that cause the test material to be ignited in a coal mine explosion environment, and scientifically evaluate the danger of the test material being ignited in the actual explosion environment. The dangerous working conditions and parameter values ​​found can provide theoretical guidance for the development of coal mine explosion / fire prevention and control work, and have wide practicality.

[0037] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for assessing the ignition hazard of materials in a coal mine explosion environment, characterized in that: The following steps are involved: (1) Analyze the environment of the material to be tested in the coal mine, determine the variation range of the type and concentration parameters of the combustible gas or dust in the mine, the variation range of the position parameters of the material to be tested, and the variation range of the blocking state parameters of obstacles along the way; (2) conducting a combustible gas or dust pipeline explosion experiment according to the variation range of each parameter determined in step (1) to determine the temperature distribution, impact range and duration of the explosion flame under different parameters; (3) constructing a numerical simulation model of the pipeline explosion experiment based on the experimental data of step (2), and constructing an actual size numerical simulation model based on the numerical simulation model and taking the actual mine size parameters as a reference, determining the explosion flame temperature distribution, impact range and duration under different parameters in the actual size numerical simulation model, and analyzing the corresponding relationship between the explosion flame temperature and duration at the position of the material to be tested; (4) Use the material ignition condition test device to test the ignition temperature and time of the material to be tested, and record the temperature range in which the material to be tested can be ignited under instantaneous heating conditions and the corresponding shortest heating time; (5) comparing the explosion flame temperature and duration at the position of the material to be tested obtained in step (3) with the ignition temperature and the shortest heating time of the material to be tested obtained in step (4), and finding parameter values ​​that make the explosion flame temperature and duration meet the ignition conditions of the material to be tested; (6) Calculate the probability of the event that the material to be tested is ignited based on the parameters determined in steps (1) and (5), and use this probability to evaluate the risk of the material to be tested being ignited in an actual explosion environment.

2. A method for assessing the ignition hazard of materials in a coal mine explosion environment as claimed in claim 1, characterized in that: The combustible gas is gas, and the combustible dust is coal dust.

3. A method for assessing the ignition hazard of materials in a coal mine explosion environment as claimed in claim 1, characterized in that: The experimental pipeline for the pipeline explosion experiment in step (2) is 3m long and has a cross-sectional area of ​​0.2×0.2m 2 .

4. A method for assessing the ignition hazard of materials in a coal mine explosion environment as claimed in claim 1, characterized in that: The materials to be tested include coal, wood, and flame-retardant conveyor belts.

5. The method for assessing the ignition hazard of materials in a coal mine explosion environment according to claim 1, characterized in that: The probability of ignition of the material to be tested in step (6) is calculated using the following calculation formula: Where: q ij is the probability of the i parameter causing the ignition event under the j condition, m is the total number of conditions, and n is the number of parameters.

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