Coal face gas overrun risk regulation and control method

Abstract

The invention relates to a coal face gas overrun risk regulation and control method, and belongs to the field of coal mine safety supervision. The method comprises the following steps: firstly, according to real-time monitoring data of gas concentration of a coal face, judging whether a gas overrun risk exists in the coal face; and if the over-limit risk exists, sequentially calculating first to third gas concentration fluctuation coefficients, and comparing the first to third gas concentration fluctuation coefficients with the gas over-limit risk critical index. If any one of the first gas concentration fluctuation coefficient, the second gas concentration fluctuation coefficient and the third gas concentration fluctuation coefficient is smaller than the gas over-limit risk critical index, production continues; and if the first to third gas concentration fluctuation coefficients are all not smaller than the gas over-limit risk critical index, coal face operation is stopped, and personnel are evacuated. According to the invention, the remote intelligent regulation and control of the gas over-limit risk is realized, the frequency of shutdown and production halt caused by gas over-limit is reduced, the productivity of a high-yield and high-efficiency mine is liberated, and the intelligent development of a coal mine is promoted.

Description

Technical Field

[0001] The invention belongs to the field of coal mine safety supervision and management, and relates to a method for regulating and controlling gas over-limit risks in a coal mining working face. Background Art

[0002] Gas exceeding the limit in coal mines is a major hidden danger for major disasters such as gas explosions, gas combustion, and gas asphyxiation. With the continuous improvement of the level of intelligent mining in coal mines, the mining speed has significantly increased, and the mining depth has increased year by year, and the problem of gas exceeding the limit has gradually become prominent. In order to reduce the risk of gas exceeding the limit and achieve source control of gas disasters, the state has issued a number of policy documents on coal mine gas safety to further improve the gas "zero exceeding the limit" target management system, and to prevent gas exceeding the limit as a key link in curbing gas accidents.

[0003] At present, coal mines mainly rely on production safety monitoring systems to implement threshold-based over-limit alarms. Once the gas concentration in the working face exceeds the threshold, production is immediately stopped and underground workers are evacuated. This passive control method for gas over-limit has greatly constrained the productivity of high-yield and efficient mines. Although with the promotion of intelligent construction of coal mines, the extraction systems, ventilation systems, and production systems of some mines have remote intelligent control functions, the advanced collaborative prevention and control technology and methods of gas over-limit risks based on coal mine intelligent systems are still in their infancy. Therefore, establishing a method for controlling the risk of gas over-limit in coal mining working faces is of great significance for reducing the risk of gas over-limit in working faces and promoting safe and efficient production in coal mines. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a method for regulating the risk of excessive gas in coal mining working faces, to realize real-time prediction and early warning of the risk of excessive gas based on a safety monitoring system, to reduce the risk of excessive gas in working faces through intelligent regulation of extraction systems, ventilation systems and production systems, and thus to ensure safe and efficient production of the working faces.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A method for controlling gas over-limit risk in a coal mining face, the method comprising:

[0007] First, based on the real-time monitoring data of gas concentration in the coal mining face, determine whether there is a risk of gas exceeding the limit in the working face;

[0008] If there is an over-limit risk, the first gas concentration fluctuation coefficient is calculated based on the maximum gas extraction negative pressure. If the first gas concentration fluctuation coefficient is less than the critical index of the gas over-limit risk, the gas extraction negative pressure is adjusted to reduce the gas over-limit risk;

[0009] If the first gas concentration fluctuation coefficient is not less than the critical index of the gas over-limit risk, the second gas concentration fluctuation coefficient is calculated based on the maximum air window opening of the ventilation system; if the second gas concentration fluctuation coefficient is less than the critical index of the gas over-limit risk, the air window opening is adjusted to reduce the gas over-limit risk;

[0010] If the second gas concentration fluctuation coefficient is not less than the critical index of the gas over-limit risk, the third gas concentration fluctuation coefficient is calculated based on the minimum coal mining machine coal cutting speed; if the third gas concentration fluctuation coefficient is less than the critical index of the gas over-limit risk, the coal mining machine coal cutting speed is adjusted to reduce the gas over-limit risk;

[0011] If the third gas concentration fluctuation coefficient is not less than the critical index of gas over-limit risk, the coal mining face operation is stopped.

[0012] Furthermore, the methods for determining whether there is a risk of excessive gas in the working face include:

[0013] Calculate the gas emission Q during the coal mining period 0 , calculate the average gas concentration during the coal mining period:

[0014]

[0015] In the formula, C i+1 represents the average gas concentration during the coal mining period, C i represents the average gas concentration during the non-mining period, Q f0 Indicates the normal air volume of the coal mining face;

[0016] According to the average gas concentration C during the coal mining period i+1 and the maximum gas concentration C max Calculate the gas concentration fluctuation coefficient k:

[0017]

[0018] If there exists k>k 0 , then there is a risk of gas exceeding the limit in the coal mining face, where k 0 It is the critical indicator of gas exceeding limit risk.

[0019] Furthermore, calculating the first gas concentration fluctuation coefficient includes:

[0020] Obtain the gas outflow Q within the time period when the gas extraction negative pressure is adjusted to the limit value 1 , calculate the average gas concentration C during this period 1 :

[0021]

[0022] Where f(·) represents the functional relationship between the gas extraction negative pressure and the gas extraction volume, p 0 Indicates the initial value of the negative pressure of extraction, p L Indicates the ultimate extraction negative pressure value;

[0023] According to the average gas concentration C during this period 1 and the maximum gas concentration C max,1 Calculate the first gas concentration fluctuation coefficient k 1 :

[0024] Furthermore, calculating the second gas concentration fluctuation coefficient includes:

[0025] Obtain the gas outflow Q during the time period when the air window opening is adjusted to the maximum 2 , calculate the average gas concentration C during this period 2 :

[0026]

[0027] In the formula, θ 0 Indicates the window opening angle under normal ventilation of the working surface, θ L Indicates the maximum wind window opening angle;

[0028] According to the average gas concentration C during this period 2 and the maximum gas concentration C max,2 Calculate the second gas concentration fluctuation coefficient k 2 :

[0029] Furthermore, the calculation of the third gas concentration fluctuation coefficient includes:

[0030] Obtain the gas emission Q during the time period when the coal cutting speed of the coal mining machine is adjusted to the minimum 3 , calculate the average gas concentration C during this period 3 :

[0031]

[0032] In the formula, Indicates the air volume on the working surface when the air window is opened to the maximum;

[0033] According to the average gas concentration C during this period 3 and minimum gas concentration C max,3 Calculate the third gas concentration fluctuation coefficient k 3 :

[0034] It should be noted that in the above calculation of the first to third gas concentration fluctuation coefficients, the time periods involved are all the same time period. 0 The period of time starting from the moment and after is recorded as time period T. In time period T, the first to third gas concentration fluctuation coefficients are calculated in turn and compared with the gas over-limit risk critical index k. 0 Comparison, that is, first calculate the gas extraction negative pressure in time period T by p 0 Gradually increase to p L When the first gas concentration fluctuation coefficient is 0 Compare; if k 1 ≥k 0 , then the window opening in the time period T is calculated by θ 0 Gradually increase to θ L When the second gas concentration fluctuation coefficient is 0 Compare; if k 2 ≥k 0 , then we continue to calculate the coal cutting speed of the coal mining machine in the time period T from v 0 Gradually decrease to v min (v min can be 0), the value of the third gas concentration fluctuation coefficient, and k 0 During the polling calculation process, if any of the first to third gas concentration fluctuation coefficients is less than the critical index k of gas over-limit risk 0 , then exit the polling calculation.

[0035] The time period T should be as short as possible to avoid excessive gas concentration during this process, which may cause shutdown or coal mine accidents.

[0036] The beneficial effects of the present invention are as follows: the present invention performs real-time prediction of gas excess risk based on working face gas concentration monitoring data, and utilizes an intelligent extraction system, an intelligent ventilation system, and an intelligent production system to achieve remote intelligent regulation of gas excess risk, thereby reducing the number of shutdowns caused by gas excess, liberating the productivity of high-yield and high-efficiency mines, and promoting the intelligent development of coal mines.

[0037] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0039] Figure 1 The figure is a schematic diagram of the process of the method of the present invention. DETAILED DESCRIPTION

[0040] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0041] See also Figure 1 , is a method for controlling gas over-limit risk in a coal mining face provided by an embodiment of the present invention, and the method is specifically as follows:

[0042] 1. Based on the real-time monitoring data of gas concentration in the coal mining face, determine whether there is a risk of gas exceeding the limit in the working face.

[0043] 1) Obtain the gas concentration monitoring data of the working face in real time and calculate the average and maximum values ​​of the gas concentration in different time periods. Assume that from T i Start production at time T i-1 ~T i The time period is the non-production stage, and the average gas concentration during this time period is C i ; T i ~T i+1 The period of time is the production stage, and the average gas concentration during this period is C i+1 , the maximum gas concentration is C max .

[0044] 2) Calculate T i ~T i+1 The amount of gas emission caused by coal mining during the period Q 0 :

[0045] Q 0 =v 0 ·d·h(T i+1 -T i )·q 吨

[0046] Among them, v 0 is the normal traction speed of the coal mining machine, m / min; d is the coal cutting depth, m; h is the mining height, m; q 吨 The amount of gas emitted per ton of coal.

[0047] 3) The relationship between the average gas concentration in the production stage and the non-production stage is:

[0048]

[0049] in, Normal air volume for the working surface.

[0050] 4) The risk of gas exceeding the limit at the working face is determined based on the gas concentration fluctuation coefficient:

[0051]

[0052] When k>k 0 , there is a risk of gas exceeding the limit in the upper corner of the working face, and the gas exceeding limit control mechanism is activated. 0 It is the critical indicator of gas exceeding limit risk, obtained through actual investigation in the mine.

[0053] 2. When there is a risk of excessive gas in the coal mining face, adjust the intelligent gas extraction system to reduce the risk of excessive gas in the face by adjusting the extraction negative pressure.

[0054] 1) Through the analysis of the upper corner drainage negative pressure and drainage data during the production of the working face, the functional relationship between the upper corner drainage negative pressure and the drainage volume is determined: Q c =f(p), and the ultimate extraction negative pressure value p is obtained max ;

[0055] 2) T i ~T i+1 When there is a risk of gas exceeding the limit within the time period, the negative pressure of extraction is adjusted from p 0 Gradually increase to the limit extraction negative pressure value p L , at this time, get the time period T i+1 ~T i+2 The average concentration of gas in the inner working face C 1 and the maximum gas concentration C max,1 :

[0056]

[0057] Among them, p 0 is the normal extraction negative pressure, kPa. Maximum gas concentration C max,1 Can be obtained through gas monitoring data.

[0058] 3) Calculate the minimum value of gas concentration fluctuation coefficient:

[0059]

[0060] If k 1 <k 0 , the extraction negative pressure p can be adjusted step by step iTo obtain the best gas extraction negative pressure.

[0061] If k 1 ≥k 0 , the intelligent ventilation system control is started.

[0062] 3. k 1 ≥k 0 When working, the intelligent ventilation system is regulated to reduce the risk of excessive gas in the working face by adjusting the opening of the wind window.

[0063] 1) Calculate the wind passing area S of the shutter automatic windshield:

[0064] S=nl(b-bcosθ),0≤θ≤90°

[0065] Where n is the number of shutters; b is the width of a single shutter, m; l is the length of a single shutter, m; θ is the opening angle of the wind window. When θ = 90°, the wind window is fully opened and the maximum air volume on the working surface is

[0066] 2) Normal ventilation volume of the working surface The window opening angle is θ 0 , when the window opening angle increases to θ i When the working face air volume for:

[0067]

[0068] At this time, the average gas concentration C 2 for:

[0069]

[0070] 3) When θ i =90°, the air volume on the working face reaches the maximum value, and the minimum value of the gas concentration fluctuation coefficient is:

[0071]

[0072] If k 2 <k 0 , then by adjusting the window opening angle θ step by step i Reduce the risk of excessive gas at the working face and obtain the best wind window opening angle.

[0073] If k 2 ≥k 0 , then start the intelligent production system regulation.

[0074] 4. k 2 ≥k 0When working, the intelligent production system is regulated to reduce the risk of excessive gas in the working face by adjusting the coal cutting speed of the coal mining machine.

[0075] 1) When k 2 ≥k 0 , then the shearer traction speed is changed from v 0 Gradually decrease to v i , the average gas concentration of the working face in this process can be expressed as:

[0076]

[0077] 2) When v i =0, the gas outflow from the working face is the smallest, and the minimum value of the gas concentration fluctuation coefficient is:

[0078]

[0079] If k 3 <k 0 , then by adjusting the shearer traction speed v step by step i Reduce the risk of excessive gas in the working face and obtain the best coal mining speed.

[0080] If k 3 ≥k 0 , the working face will stop production and the workers will be evacuated immediately.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A method for controlling gas over-limit risk in a coal mining face, characterized by: First, based on the real-time monitoring data of gas concentration in the coal mining face, determine whether there is a risk of gas exceeding the limit in the working face; If there is an over-limit risk, the first gas concentration fluctuation coefficient is calculated based on the maximum gas extraction negative pressure. If the first gas concentration fluctuation coefficient is less than the critical index of the gas over-limit risk, the gas extraction negative pressure is adjusted to reduce the gas over-limit risk; If the first gas concentration fluctuation coefficient is not less than the critical index of the gas over-limit risk, the second gas concentration fluctuation coefficient is calculated based on the maximum air window opening of the ventilation system; if the second gas concentration fluctuation coefficient is less than the critical index of the gas over-limit risk, the air window opening is adjusted to reduce the gas over-limit risk; If the second gas concentration fluctuation coefficient is not less than the critical index of the gas over-limit risk, the third gas concentration fluctuation coefficient is calculated based on the minimum coal mining machine coal cutting speed; if the third gas concentration fluctuation coefficient is less than the critical index of the gas over-limit risk, the coal mining machine coal cutting speed is adjusted to reduce the gas over-limit risk; If the third gas concentration fluctuation coefficient is not less than the critical index of gas over-limit risk, the coal mining face operation is stopped.

2. The method for controlling gas over-limit risk in a coal mining face according to claim 1, characterized in that: Methods for judging whether there is a risk of excessive gas in the working face include: Calculate the gas emission Q0 during the coal mining period and the average gas concentration during the coal mining period: In the formula, C i+1 represents the average gas concentration during the coal mining period, C i Represents the average gas concentration during the non-coal mining period, Indicates the normal air volume of the coal mining face; According to the average gas concentration C during the coal mining period i+1 and the maximum gas concentration C max Calculate the gas concentration fluctuation coefficient k: If k>k0, there is a risk of excessive gas in the coal mining face, where k0 is the critical indicator of the risk of excessive gas.

3. The method for controlling gas over-limit risk in a coal mining face according to claim 1, characterized in that: The calculating of the first gas concentration fluctuation coefficient comprises: The gas outflow Q1 in the time period when the gas extraction negative pressure is adjusted to the limit value is obtained, and the average gas concentration C1 in the time period is calculated: In the formula, f(·) represents the functional relationship between the gas drainage negative pressure and the gas drainage volume, p0 represents the initial value of the drainage negative pressure, and p L Indicates the ultimate extraction negative pressure value; According to the average gas concentration C1 and the maximum gas concentration C max,1 Calculate the first gas concentration fluctuation coefficient k1:

4. The method for controlling gas over-limit risk in a coal mining face according to claim 1, characterized in that: The calculating of the second gas concentration fluctuation coefficient comprises: Obtain the gas outflow Q2 during the time period when the air window opening is adjusted to the maximum, and calculate the average gas concentration C2 during the time period: In the formula, θ0 represents the window opening angle under normal ventilation of the working surface, θ L Indicates the maximum wind window opening angle; According to the average gas concentration C2 and the maximum gas concentration C max,2 Calculate the second gas concentration fluctuation coefficient k2:

5. The method for controlling gas over-limit risk in a coal mining face according to claim 1, characterized in that: The calculating of the third gas concentration fluctuation coefficient comprises: Obtain the gas emission Q3 during the time period when the coal cutting speed of the coal mining machine is adjusted to the minimum, and calculate the average gas concentration C3 during the time period: In the formula, Q fmax Indicates the air volume on the working surface when the air window is opened to the maximum; According to the average gas concentration C3 and the minimum gas concentration C max,3 Calculate the third gas concentration fluctuation coefficient k3:

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