Quantitative coal mining control system for preventing gas overrun in coal mine

Abstract

This invention discloses a quantitative coal mining control system for preventing excessive gas levels in coal mines, including a gas volume fraction monitoring probe, a safety early warning and monitoring module, and a gas exceeding limit quantitative control module. The gas volume fraction monitoring probe includes a monitoring probe T1 located at the end of the transport roadway near the coal mining face, a monitoring probe T2 located at the coal mining face, a monitoring probe T3 located at the end of the return airway near the coal mining face, a monitoring probe T4 located at the end of the return airway away from the coal mining face, and monitoring probes T1, T2, T3, and T4 are respectively connected to the safety early warning and monitoring module and the gas exceeding limit quantitative control module.

Description

Technical Field

[0001] This invention relates to the field of coal mining, and in particular to a quantitative coal mining control system for preventing coal mine gas exceedances. Background Technology

[0002] With the continuous development of the coal mining industry, various methods for predicting and analyzing gas emission in different areas of the working face have emerged. However, most of these methods only serve the purpose of prediction and alarm, and cannot adaptively adjust the coal cutting speed based on the gas concentration, resulting in poor performance. Furthermore, existing gas concentration feedback control methods cannot precisely increase or decrease the coal cutting or release volume according to the actual on-site coordination needs, thus failing to achieve precise control over coordination between mining and release and gas safety, which poses certain challenges to coal mining operations. Summary of the Invention

[0003] The purpose of this invention is to address the above-mentioned problems by providing a simple, safe, and quantitative coal mining control system for preventing coal mine gas exceedances.

[0004] To achieve the above objectives, the technical solution of the present invention is as follows:

[0005] A quantitative coal mining control system for preventing excessive methane levels in coal mines includes methane volume fraction monitoring probes, a safety early warning and monitoring module, and a methane exceeding limit quantitative control module. The methane volume fraction monitoring probes include a monitoring probe T1 located near the coal face in the transport roadway, a monitoring probe T2 located at the coal face, a monitoring probe T3 located near the coal face in the return airway, and a monitoring probe T4 located away from the coal face in the return airway. The monitoring probes T1, T2, T3, and T4 are respectively connected to the safety early warning and monitoring module and the methane exceeding limit quantitative control module.

[0006] Furthermore, the safety early warning and monitoring module includes a working face concentration exceeding limit early warning unit, a coal and gas outburst early warning unit, a goaf gas emission prediction unit, a coal mining gas emission prediction unit, a coal release gas emission prediction unit, and a stable stage coal wall emission prediction unit. The working face concentration exceeding limit early warning unit performs early warning operations by detecting whether monitoring probes T1, T2, and T3 are within the early warning range through a pre-set early warning range. The coal and gas outburst early warning unit performs early warning operations by detecting the gas concentration and gas concentration increment of monitoring probe T3.

[0007] Furthermore, the prediction operation of the coal wall outflow prediction unit in the stable phase includes the following steps:

[0008] S31. Obtain relevant coal and rock data, and under laboratory conditions, install a gas monitoring probe at the downwind end. Conduct a simulation experiment using fresh air with the same flow rate as the roadway, and statistically analyze the time variation samples of exposure time and gas volume fraction in the laboratory.

[0009] S32. After multiple experiments, a scatter plot of exposure time and coal wall gas emission volume fraction was plotted. By filtering and fitting the scatter plot, the coal wall gas emission regularity curve was obtained.

[0010] S33. Based on the coal face gas emission pattern curve y=a+b*e ct The gas concentration C during the gas release stage of the unstable coal wall was calculated. 非稳煤壁 m 3 / min, stable release period of coal wall gas T 煤壁稳定 and the gas concentration C during the stable release phase of coal wall gas. 煤壁 m 3 / min; where y is the coal wall gas volume fraction, %, t is the exposure time, min, and a, b, c are the parameters to be fitted;

[0011] S34. Based on the gas volume fraction and air volume during the stable gas release stage of the coal wall, the absolute gas emission rate during the stable gas release stage is calculated; the calculation formula is as follows:

[0012] Q 煤壁绝 =QC 煤壁 / 100;

[0013] Among them, Q 煤壁绝 The absolute gas emission rate during the stable gas release phase of the coal face, in m 3 / min; Q is the return air volume, m 3 / min; C 煤壁 The methane concentration during the stable release phase of coal face methane is %.

[0014] Furthermore, the prediction operation of the goaf gas emission prediction unit includes the following steps:

[0015] S41. When the coal mining machine stops mining and the tail of the support stops releasing coal, and the duration of the cessation of coal release exceeds the gas stable release cycle T. 煤壁稳定 At that time, the gas emission from the working face = the absolute gas emission from the goaf + the absolute gas emission during the stable gas release stage of the coal wall;

[0016] S42, then the absolute gas emission rate Q in the goaf area 采空区绝 The calculation formula is:

[0017] Q 采空区绝 =Q 停产工作面 -Q 煤壁绝 =Q(T) 3停产-T 1停产 ) / 100-Q 煤壁绝 ;

[0018] Among them, Q 采空区绝 The absolute gas emission rate in the goaf is given in m. 3 / min; Q 停产工作面 For coal mining and coal discharge stoppage time exceeding T 煤壁稳定 Gas emission rate at working face, m 3 / min; Q 煤壁绝 The absolute gas emission rate during the stable gas release phase of the coal face, in m 3 / min; Q is the return air volume, m 3 / min; T 3停产 For coal mining and coal discharge stoppage time exceeding T 煤壁稳定 At that time, the gas concentration monitored by probe T3 was %, %. 1停产 For coal mining and coal discharge stoppage time exceeding T 煤壁稳定 At that time, the gas concentration monitored by probe T1 was %.

[0019] The prediction calculation formula of the coal mining gas emission prediction unit is as follows:

[0020] Q 采煤绝 =Q 相 *(B 截深 *V 采煤 *H 采煤 *ρ 煤 );

[0021] Among them, Q 采煤绝 The absolute gas emission rate during coal mining by the coal mining machine is expressed in m. 3 / min; Q 相 The relative gas emission rate of coal, m 3 / t;B 截深 V represents the cutting depth of the coal mining machine, in meters. 采煤 H represents the cutting speed of the coal mining machine, in m / min. 采煤 ρ is the cutting height of the coal mining machine, in meters (m); 煤 The bulk density of coal, t / m³ 3 .

[0022] Furthermore, the prediction operation of the coal-fired gas emission prediction unit includes the following steps:

[0023] S61. When the coal mining machine stops mining and the coal is being discharged normally at the tail of the support, the formula for calculating the absolute gas emission rate during coal discharge at the tail of the support is as follows:

[0024] Q 放绝1 =Q(T) 3停产 -T 1停产 ) / 100-Q 煤壁绝 -Q采空区绝 ;

[0025] Among them, Q 放绝1 The absolute gas emission rate at the tail of the support when the coal mining machine is stopped, in m. 3 / min; Q is the return air volume, m 3 / min; T 3停产1 For coal mining stoppage time exceeding T 煤壁稳定 At that time, the gas concentration monitored by probe T3 was %, %. 1停产1 For coal mining stoppage time exceeding T 煤壁稳定 At that time, the gas concentration monitored by probe T1, %; Q 煤壁绝 The absolute gas emission rate during the stable gas release phase of the coal face, in m 3 / min; Q 采空区绝 The absolute gas emission rate in the goaf is given in m. 3 / min;

[0026] S62. Under normal mining conditions and normal coal discharge at the tail of the support, the formula for calculating the absolute gas emission rate of the unstable coal wall is:

[0027] Q 非稳煤壁 =QC 非稳煤壁 / 100;

[0028] Among them, Q 非稳煤壁 The absolute gas emission rate of an unstabilized coal face, in m 3 / min; Q is the return air volume, m 3 / min; C 非稳煤壁 The methane concentration during the unsteady coal face methane release stage, in %;

[0029] S63. Under normal coal mining conditions and normal coal discharge at the tail of the support, the formula for calculating the absolute gas emission rate during coal discharge at the tail of the support is as follows:

[0030] Q 放绝1 =Q(T) 3停产 -T 1停产 ) / 100-Q 非稳煤壁 -Q 采空区绝 ;

[0031] Among them, Q 放绝1 The absolute gas emission rate at the tail of the support when the coal mining machine is stopped, in m. 3 / min; Q is the return air volume, m 3 / min; T 3停产1 For coal mining stoppage time exceeding T 煤壁稳定 At that time, the gas concentration monitored by probe T3 was %, %. 1停产1 For coal mining stoppage time exceeding T 煤壁稳定 At that time, the gas concentration monitored by probe T1, %; Q非稳煤壁 The absolute gas emission rate of an unstabilized coal face, in m 3 / min; Q 采空区绝 The absolute gas emission rate in the goaf is given in m. 3 / min;

[0032] S64. Draw a scatter plot of the number of coal outlets and the amount of coal gas emitted, and fit the function relationship between the number of coal outlets and the amount of coal gas emitted:

[0033] q=mn 2 +kn+a;

[0034] Where q is the amount of gas emitted during coal blasting, and m 3 / min; n is the number of coal outlets; m, k, and a are constants.

[0035] Furthermore, the control operation of the gas over-limit control module includes the following steps:

[0036] S71. Set the safe gas volume fraction C at the working face. 安全 ;

[0037] S72. Determine the actual gas concentration T at the working face based on the monitoring probe T3. 3实际 ;

[0038] S73. The formula for calculating the absolute gas emission rate at a safe concentration is as follows:

[0039] Q1 = C 安全 *Q*K / 100;

[0040] Where Q1 is the absolute gas emission rate at a safe concentration, m 3 / min; C 安全 Safety gas concentration, %; Q is return air volume, m³. 3 / min; K is the safety factor;

[0041] S74. Calculate the absolute gas emission rate at the actual working face. The calculation formula is as follows:

[0042] Q2 = T 3实际 *Q / 100;

[0043] Where Q2 is the actual absolute gas emission at the working face, in m 3 / min; T 3实际 The actual gas concentration at the working face is %, Q is the return air volume, m³. 3 / min;

[0044] S75. Calculate the allowable increase / decrease in gas emission at the working face. The calculation formula is as follows:

[0045] Q 允许=Q1-Q2;

[0046] Among them, Q 允许 To allow for an increase / decrease in absolute gas emission at the working face, m 3 / min; Q1 is the absolute gas emission rate at a safe concentration, m 3 / min; Q2 is the actual absolute gas emission rate at the working face, m 3 / min;

[0047] S76. Calculate the working face mining coordination ratio under the current cycle. The calculation formula is as follows:

[0048] P 采放协调 =J 放煤 / J 采煤 ;

[0049] Among them, P 采放协调 The ratio of current coal mining efficiency to coal discharge efficiency at the working face, %; J 放煤 J represents the number of coal supports that have been deployed in the current cycle; 采煤 This represents the number of coal-mined supports in the current cycle.

[0050] S76. Set the standard coordination ratio range for mining and releasing;

[0051] S77. Compare the working face mining-to-discharge coordination ratio with the standard mining-to-discharge coordination ratio. If the working face mining-to-discharge coordination ratio is within the standard coordination ratio range, the mining speed and the number of coal outlets should be increased or decreased simultaneously. If the working face mining-to-discharge coordination ratio is less than the standard coordination ratio range, when the working face needs to increase gas emission, the number of coal outlets should be increased first, followed by increasing the coal cutting speed. When the working face needs to reduce gas emission, the coal cutting speed should be decreased first, followed by decreasing the number of coal outlets. If the working face mining-to-discharge coordination ratio is greater than the standard coordination ratio range, when the working face needs to increase gas emission, the coal cutting speed should be increased first, followed by increasing the number of coal outlets. When the working face needs to reduce gas emission, the number of coal outlets should be decreased first, followed by decreasing the coal cutting speed.

[0052] S78. Calculate the varying coal cutting speed. The calculation formula is as follows:

[0053] V 允许 =Q 允许 / (Q 相 *B 截深 *H 采煤 *ρ 煤 );

[0054] Among them, V 允许 To allow for increasing / decreasing the coal mining machine speed, in m / min; Q 允许 To allow for an increase / decrease in absolute gas emission at the working face, m 3 / min; Q 相 The relative gas emission rate of coal, m3 / t;B 截深 H represents the cutting depth of the coal mining machine, in meters (m). 采煤 ρ is the cutting height of the coal mining machine, in meters (m); 煤 The bulk density of coal, t / m³ 3 ;

[0055] S79. Calculate the number of coal discharge openings that vary. The calculation formula is as follows:

[0056] Q 允许 =mt 2 +kt+a;

[0057]

[0058] Among them, Q 允许 To allow for an increase / decrease in absolute gas emission at the working face, m 3 / min; t is the allowable increase / decrease in the coal discharge port quantity; m, k, and a are constants.

[0059] Compared with the prior art, the advantages and positive effects of this invention are:

[0060] 1. This invention can predict the amount of gas emitted from the goaf, the amount of gas emitted from the coal mining machine, the amount of gas emitted during the coal release stage, and the amount of gas emitted from the coal wall in real time based on the condition of the coal mining face, and perform alarm operations.

[0061] 2. This invention can calculate the absolute increase / decrease in gas emission at a coal mining face under conditions that ensure safe gas concentration and safe production at the working face;

[0062] 3. The present invention can calculate the allowable increase / decrease in coal cutting speed based on factors such as coal cutting height, coal cutting depth, and coal density through coal cutting quantity feedback;

[0063] 4. This invention can analyze the coal discharge port and the coal discharge gas emission function to achieve feedback control of the number of coal discharge ports opened;

[0064] 5. This invention can precisely increase or decrease the amount of coal cut and released based on the actual on-site mining and release coordination needs, thereby achieving precise control of mining and release coordination and gas safety.

[0065] The quantitative coal mining control system for preventing excessive coal gas levels disclosed in this invention integrates functions such as monitoring and early warning of gas concentration at the working face, precise analysis of gas emission at various locations on the working face, intelligent correlation control between working face gas safety and coal mining volume, dynamic coordination of mining speed, and prevention of top coal loss and incoordination between mining and coal mining volume affecting the working face recovery speed. It provides new technical paths and solutions for intelligent coal mine production, intelligent coal mine safety monitoring and control, and linkage control of mining and safety processes, opening a new chapter for the intelligent construction of mines. Attached Figure Description

[0066] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0067] Figure 1 This is a schematic diagram of the structure of the present invention;

[0068] Figure 2 This is a structural diagram of the present invention;

[0069] Figure 3 This is a flowchart of the prediction process for the safety early warning and monitoring module. Detailed Implementation

[0070] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art to all other embodiments obtained without creative effort should be included within the protection scope of the present invention.

[0071] like Figure 1 , Figure 2 and Figure 3As shown in the figure, this embodiment discloses a quantitative coal mining control system for preventing coal mine gas exceedances, including a gas volume fraction monitoring probe, a safety early warning and monitoring module, and a gas exceedance quantitative control module. The gas volume fraction monitoring probe includes a monitoring probe T1 installed at the end of the transport roadway near the coal mining face, a monitoring probe T2 installed at the coal mining face, a monitoring probe T3 installed at the end of the return airway near the coal mining face, a monitoring probe T4 installed at the end of the return airway away from the coal mining face, and monitoring probes T1, T2, T3, and T4 are respectively connected to the safety early warning and monitoring module and the gas exceedance quantitative control module.

[0072] The safety early warning and monitoring module includes a working face concentration exceeding limit early warning unit, a coal and gas outburst early warning unit, a goaf gas emission prediction unit, a coal mining gas emission prediction unit, a coal release gas emission prediction unit, and a stable stage coal wall emission prediction unit.

[0073] When the working face concentration exceeding the limit early warning unit realizes the early warning operation, it pre-sets the early warning range and detects whether the gas concentration values ​​of monitoring probes T1, T2 and T3 are within the early warning range. If they are within the early warning range, the front-end early warning is issued; otherwise, no early warning is issued.

[0074] When the coal and gas outburst early warning unit performs early warning operation, it detects the gas concentration of the monitoring probe T3. When the gas concentration value detected by the monitoring probe T3 is >0.8% and the gas concentration increment is >1% / min, a coal and gas outburst early warning is issued.

[0075] The prediction operation of the coal wall outflow prediction unit in the stable phase includes the following steps:

[0076] S31. Obtain relevant coal and rock data, and under laboratory conditions, install a gas monitoring probe at the downwind end. Conduct a simulation experiment using fresh air with the same flow rate as the roadway, and statistically analyze the time variation samples of exposure time and gas volume fraction in the laboratory.

[0077] S32. After multiple experiments, a scatter plot of exposure time versus coal wall gas emission volume fraction was plotted. By filtering and fitting the scatter plot, the coal wall gas emission pattern curve y = a + b*e was obtained. ct ;

[0078] S33. Based on the coal face gas emission pattern curve y=a+b*e ct The gas concentration C during the gas release stage of the unstable coal wall was calculated. 非稳煤壁 Stable release cycle of coal wall gas T 煤壁稳定 and the gas concentration C during the stable release phase of coal wall gas. 煤壁Where y is the volume fraction of gas in the coal wall, t is the exposure time, and a, b, and c are the parameters to be fitted.

[0079] S34. Based on the gas volume fraction and air volume during the stable gas release stage of the coal wall, the absolute gas emission rate during the stable gas release stage is calculated; the calculation formula is as follows:

[0080] Q 煤壁绝 =QC 煤壁 / 100;

[0081] Among them, Q 煤壁绝 The absolute gas emission rate during the stable gas release phase of the coal face, in m 3 / min; Q is the return air volume, m 3 / min; C 煤壁 The methane concentration during the stable release phase of coal face methane is %.

[0082] The prediction operation of the goaf gas emission prediction unit includes the following steps:

[0083] S41. When the coal mining machine stops mining and the tail of the support stops releasing coal, and the duration of the cessation of coal release exceeds the gas stable release cycle T. 煤壁稳定 At that time, the gas emission from the working face = the absolute gas emission from the goaf + the absolute gas emission during the stable gas release stage of the coal wall;

[0084] S42, then the absolute gas emission rate Q in the goaf area 采空区绝 The calculation formula is:

[0085] Q 采空区绝 =Q 停产工作面 -Q 煤壁绝 =Q(T) 3停产 -T 1停产 ) / 100-Q 煤壁绝 ;

[0086] Among them, Q 采空区绝 The absolute gas emission rate in the goaf is given in m. 3 / min; Q 停产工作面 For coal mining and coal discharge stoppage time exceeding T 煤壁稳定 Gas emission rate at working face, m 3 / min; Q 煤壁绝 The absolute gas emission rate during the stable gas release phase of the coal face, in m 3 / min; Q is the return air volume, m 3 / min; T 3停产 For coal mining and coal discharge stoppage time exceeding T 煤壁稳定 At that time, the gas concentration monitored by probe T3 was %, %. 1停产 For coal mining and coal discharge stoppage time exceeding T 煤壁稳定At that time, the gas concentration monitored by probe T1 was %.

[0087] The prediction calculation formula of the coal mining gas emission prediction unit is as follows:

[0088] Q 采煤绝 =Q 相 *(B 截深 *V 采煤 *H 采煤 *ρ 煤 );

[0089] Among them, Q 采煤绝 The absolute gas emission rate during coal mining by the coal mining machine is expressed in m. 3 / min; Q 相 The relative gas emission rate of coal, m 3 / t;B 截深 V represents the cutting depth of the coal mining machine, in meters. 采煤 H represents the cutting speed of the coal mining machine, in m / min. 采煤 ρ is the cutting height of the coal mining machine, in m / min; 煤 The bulk density of coal, t / m³ 3 .

[0090] The prediction operation of the coal gas emission prediction unit includes the following steps:

[0091] S61. When the coal mining machine stops mining and the coal is being discharged normally at the tail of the support, the formula for calculating the absolute gas emission rate during coal discharge at the tail of the support is as follows:

[0092] Q 放绝1 =Q(T) 3停产 -T 1停产 ) / 100-Q 煤壁绝 -Q 采空区绝 ;

[0093] Among them, Q 放绝1 The absolute gas emission rate at the tail of the support when the coal mining machine is stopped, in m. 3 / min; Q is the return air volume, m 3 / min; T 3停产1 For coal mining stoppage time exceeding T 煤壁稳定 At that time, the gas concentration monitored by probe T3 was %, %. 1停产1 For coal mining stoppage time exceeding T 煤壁稳定 At that time, the gas concentration monitored by probe T1, %; Q 煤壁绝 The absolute gas emission rate during the stable gas release phase of the coal face, in m 3 / min; Q 采空区绝 The absolute gas emission rate in the goaf is given in m. 3 / min;

[0094] S62. Under normal mining conditions and normal coal discharge at the tail of the support, the formula for calculating the absolute gas emission rate of the unstable coal wall is:

[0095] Q 非稳煤壁 =QC 非稳煤壁 / 100;

[0096] Among them, Q 非稳煤壁 The absolute gas emission rate of an unstabilized coal face, in m 3 / min; Q is the return air volume, m 3 / min; C 非稳煤壁 The methane concentration during the unsteady coal face methane release stage, in %;

[0097] S63. Under normal coal mining conditions and normal coal discharge at the tail of the support, the formula for calculating the absolute gas emission rate during coal discharge at the tail of the support is as follows:

[0098] Q 放绝1 =Q(T) 3停产 -T 1停产 ) / 100-Q 非稳煤壁 -Q 采空区绝 ;

[0099] Among them, Q 放绝1 The absolute gas emission rate at the tail of the support when the coal mining machine is stopped, in m. 3 / min; Q is the return air volume, m 3 / min; T 3停产1 For coal mining stoppage time exceeding T 煤壁稳定 At that time, the gas concentration monitored by probe T3 was %, %. 1停产1 For coal mining stoppage time exceeding T 煤壁稳定 At that time, the gas concentration monitored by probe T1, %; Q 非稳煤壁 The absolute gas emission rate of an unstabilized coal face, in m 3 / min; Q 采空区绝 The absolute gas emission rate in the goaf is given in m. 3 / min;

[0100] S64. Draw a scatter plot of the number of coal outlets and the amount of coal gas emitted, and fit the function relationship between the number of coal outlets and the amount of coal gas emitted:

[0101] q=mn 2 +kn+a;

[0102] Where q is the amount of gas emitted from coal discharge; n is the number of coal discharge outlets; and m, k, and a are constants.

[0103] The control operation of the gas over-limit control module includes the following steps:

[0104] S71. Set the safe gas volume fraction C at the working face. 安全 ;

[0105] S72. Determine the actual gas concentration T at the working face based on the monitoring probe T3. 3实际 ;

[0106] S73. The formula for calculating the absolute gas emission rate at a safe concentration is as follows:

[0107] Q1 = C 安全 *Q*K / 100;

[0108] Where Q1 is the absolute gas emission rate at a safe concentration, m 3 / min; C 安全 Safety gas concentration, %; Q is return air volume, m³. 3 / min; K is the safety factor, taken as 0.9;

[0109] S74. Calculate the absolute gas emission rate at the actual working face. The calculation formula is as follows:

[0110] Q2 = T 3实际 *Q / 100;

[0111] Where Q2 is the actual absolute gas emission at the working face, in m 3 / min; T 3实际 The actual gas concentration at the working face monitored by probe T3 is expressed as a percentage (%); Q represents the return air volume (m³). 3 / min;

[0112] S75. Calculate the allowable increase / decrease in gas emission at the working face. The calculation formula is as follows:

[0113] Q 允许 =Q1-Q2;

[0114] Among them, Q 允许 To allow for an increase / decrease in the absolute gas emission rate at the working face (positive values ​​indicate an increase, negative values ​​indicate a decrease), m 3 / min; Q1 is the absolute gas emission rate at a safe concentration, m 3 / min; Q2 is the actual absolute gas emission rate at the working face, m 3 / min;

[0115] S76. Calculate the working face mining coordination ratio under the current cycle. The calculation formula is as follows:

[0116] P 采放协调 =J 放煤 / J 采煤 ;

[0117] Among them, P 采放协调The ratio of current coal mining efficiency to coal discharge efficiency at the working face, %; J 放煤 J represents the number of coal supports already deployed in the current cycle. 采煤 This represents the number of coal supports already mined in the current cycle;

[0118] S76. Set the standard coordination ratio range for mining and releasing;

[0119] S77. Compare the working face mining-to-discharge coordination ratio with the standard mining-to-discharge coordination ratio. If the working face mining-to-discharge coordination ratio is within the standard coordination ratio range, the mining speed and the number of coal outlets should be increased or decreased simultaneously. If the working face mining-to-discharge coordination ratio is less than the standard coordination ratio range, when the working face needs to increase gas emission, the number of coal outlets should be increased first, followed by increasing the coal cutting speed. When the working face needs to reduce gas emission, the coal cutting speed should be decreased first, followed by decreasing the number of coal outlets. If the working face mining-to-discharge coordination ratio is greater than the standard coordination ratio range, when the working face needs to increase gas emission, the coal cutting speed should be increased first, followed by increasing the number of coal outlets. When the working face needs to reduce gas emission, the number of coal outlets should be decreased first, followed by decreasing the coal cutting speed.

[0120] S78. Calculate the varying coal cutting speed. The calculation formula is as follows:

[0121] V 允许 =Q 允许 / (Q 相 *B 截深 *H 采煤 *ρ 煤 );

[0122] Among them, V 允许 To allow for increasing / decreasing the coal mining machine speed (positive value for increase, negative value for decrease), m / min; Q 允许 To allow for an increase / decrease in the absolute gas emission rate at the working face (positive values ​​indicate an increase, negative values ​​indicate a decrease), m 3 / min; Q 相 The relative gas emission rate of coal, m 3 / t;B 截深 H represents the cutting depth of the coal mining machine, in meters (m). 采煤 ρ is the cutting height of the coal mining machine, in m / min; 煤 The bulk density of coal, t / m³ 3 ;

[0123] S79. Calculate the number of coal discharge openings that vary. The calculation formula is as follows:

[0124] Q 允许 =mt 2 +kt+a;

[0125]

[0126] Among them, Q 允许To allow for an increase / decrease in the absolute gas emission rate at the working face (positive values ​​indicate an increase, negative values ​​indicate a decrease), m 3 / min; t is the allowable increase / decrease in the coal discharge port quantity (Q) 允许 Positive values ​​increase, Q 允许 Negative values ​​indicate a decrease; m, k, and a are constants.

[0127] The present invention has the following beneficial effects:

[0128] 1. This invention can predict the amount of gas emitted from the goaf, the amount of gas emitted from the coal mining machine, the amount of gas emitted during the coal release stage, and the amount of gas emitted from the coal wall in real time based on the condition of the coal mining face, and perform alarm operations.

[0129] 2. This invention can calculate the absolute increase / decrease in gas emission at a coal mining face under conditions that ensure safe gas concentration and safe production at the working face;

[0130] 3. The present invention can calculate the allowable increase / decrease in coal cutting speed based on factors such as coal cutting height, coal cutting depth, and coal density through coal cutting quantity feedback;

[0131] 4. This invention can analyze the coal discharge port and the coal discharge gas emission function to achieve feedback control of the number of coal discharge ports opened;

[0132] 5. This invention can precisely increase or decrease the amount of coal cut and released based on the actual on-site mining and release coordination needs, thereby achieving precise control of mining and release coordination and gas safety.

[0133] The quantitative coal mining control system for preventing excessive coal gas levels disclosed in this invention integrates functions such as monitoring and early warning of gas concentration at the working face, precise analysis of gas emission at various locations on the working face, intelligent correlation control between working face gas safety and coal mining volume, dynamic coordination of mining speed, and prevention of top coal loss and incoordination between mining and coal mining volume affecting the working face recovery speed. It provides new technical paths and solutions for intelligent coal mine production, intelligent coal mine safety monitoring and control, and linkage control of mining and safety processes, opening a new chapter for the intelligent construction of mines.

Claims

1. A quantitative coal mining control system for preventing excessive gas levels in coal mines, characterized in that: The quantitative coal mining control system includes a gas volume fraction monitoring probe, a safety early warning and monitoring module, and a gas over-limit quantitative control module. The gas volume fraction monitoring probe includes a monitoring probe T1 installed at the end of the transport roadway near the coal mining face, a monitoring probe T2 installed at the coal mining face, a monitoring probe T3 installed at the end of the return air roadway near the coal mining face, and a monitoring probe T4 installed at the end of the return air roadway away from the coal mining face. The monitoring probes T1, T2, T3, and T4 are respectively connected to the safety early warning and monitoring module and the gas over-limit quantitative control module. The control operation of the gas over-limit control module includes the following steps: S71. Set the safe gas volume fraction C at the working face. 安全 ; S72. Determine the actual gas concentration T at the working face based on the monitoring probe T3. 3实际 ; S73. The formula for calculating the absolute gas emission rate at a safe concentration is as follows: Q1=C 安全 *Q*K / 100; Where Q1 is the absolute gas emission rate at a safe concentration, m 3 / min; C 安全 The safe gas concentration is %; Q is the return air volume, m³. 3 / min; K is the safety factor; S74. Calculate the absolute gas emission rate at the actual working face. The calculation formula is as follows: Q2=T 3实际 *Q / 100; Where Q2 is the actual absolute gas emission at the working face, in m 3 / min; T 3实际 The actual gas concentration at the working face is %; Q is the return air volume, m³. 3 / min; S75. Calculate the allowable increase / decrease in gas emission at the working face. The calculation formula is as follows: Q 允许 =Q1- Q2; Among them, Q 允许 To allow for an increase / decrease in absolute gas emission at the working face, m 3 / min; Q1 is the absolute gas emission rate at a safe concentration, m 3 / min; Q2 is the actual absolute gas emission rate at the working face, m 3 / min; S76. Calculate the working face mining coordination ratio under the current cycle. The calculation formula is as follows: P 采放协调 =J 放煤 / J 采煤 ; Among them, P 采放协调 The ratio of current coal mining efficiency to coal discharge efficiency at the working face, %; J 放煤 J represents the number of coal supports that have been deployed in the current cycle; 采煤 This represents the number of coal-mined supports in the current cycle. S76. Set the standard coordination ratio range for mining and releasing; S77. Compare the working face mining-to-discharge coordination ratio with the standard mining-to-discharge coordination ratio. If the working face mining-to-discharge coordination ratio is within the standard coordination ratio range, the mining speed and the number of coal outlets should be increased or decreased simultaneously. If the working face mining-to-discharge coordination ratio is less than the standard coordination ratio range, when the working face needs to increase gas emission, the number of coal outlets should be increased first, followed by increasing the coal cutting speed. When the working face needs to reduce gas emission, the coal cutting speed should be decreased first, followed by decreasing the number of coal outlets. If the working face mining-to-discharge coordination ratio is greater than the standard coordination ratio range, when the working face needs to increase gas emission, the coal cutting speed should be increased first, followed by increasing the number of coal outlets. When the working face needs to reduce gas emission, the number of coal outlets should be decreased first, followed by decreasing the coal cutting speed. S78. Calculate the varying coal cutting speed. The calculation formula is as follows: V 允许 =Q 允许 / (Q 相 *B 截深 *H 采煤 *ρ 煤 ); Among them, V 允许 To allow for increasing / decreasing the coal mining machine speed, in m / min; Q 允许 To allow for an increase / decrease in absolute gas emission at the working face, m 3 / min; Q 相 The relative gas emission rate of coal, m 3 / t;B 截深 H represents the cutting depth of the coal mining machine, in meters (m). 采煤 ρ is the cutting height of the coal mining machine, in meters (m); 煤 The bulk density of coal, t / m³ 3 ; S79. Calculate the number of coal discharge openings that vary. The calculation formula is as follows: Q 允许 =mt 2 +kt+a; ； Among them, Q 允许 To allow for an increase / decrease in absolute gas emission at the working face, m 3 / min; t is the allowable increase / decrease in the coal discharge port quantity; m, k, and a are constants.

2. The quantitative coal mining control system for preventing coal mine gas exceedances as described in claim 1, characterized in that: The safety early warning and monitoring module includes a working face concentration exceeding limit early warning unit, a coal and gas outburst early warning unit, a goaf gas emission prediction unit, a coal mining gas emission prediction unit, a coal release gas emission prediction unit, and a stable stage coal wall emission prediction unit. The working face concentration exceeding limit early warning unit performs early warning operations by detecting whether monitoring probes T1, T2, and T3 are within the early warning range through a pre-set early warning range. The coal and gas outburst early warning unit performs early warning operations by detecting the gas concentration and gas concentration increment of monitoring probe T3.

3. The quantitative coal mining control system for preventing coal mine gas exceedances as described in claim 2, characterized in that: The prediction operation of the coal wall outflow prediction unit in the stable phase includes the following steps: S31. Obtain relevant coal and rock data, and under laboratory conditions, install a gas monitoring probe at the downwind end. Conduct a simulation experiment using fresh air with the same flow rate as the roadway, and statistically analyze the time variation samples of exposure time and gas volume fraction in the laboratory. S32. After multiple experiments, a scatter plot of exposure time and coal wall gas emission volume fraction was plotted. By filtering and fitting the scatter plot, the coal wall gas emission regularity curve was obtained. S33. Based on the coal face gas emission pattern curve y=a+b*e ct The gas concentration C during the gas release stage of the unstable coal wall was calculated. 非稳煤壁 Stable release cycle of coal wall gas T 煤壁稳定 and the gas concentration C during the stable release phase of coal wall gas. 煤壁 Where y is the volume fraction of gas in the coal wall, t is the exposure time, and a, b, and c are the parameters to be fitted. S34. Based on the gas volume fraction and air volume during the stable gas release stage of the coal wall, the absolute gas emission rate during the stable gas release stage is calculated; the calculation formula is as follows: Q 煤壁绝 =QC 煤壁 / 100; Among them, Q 煤壁绝 The absolute gas emission rate during the stable gas release phase of the coal face, in m 3 / min; Q is the return air volume, m 3 / min; C 煤壁 The methane concentration during the stable release phase of coal face methane is %.

4. The quantitative coal mining control system for preventing coal mine gas exceedances as described in claim 3, characterized in that: The prediction operation of the goaf gas emission prediction unit includes the following steps: S41. When the coal mining machine stops mining and the tail of the support stops releasing coal, and the duration of the cessation of coal release exceeds the gas stable release cycle T. 煤壁稳定 At that time, the gas emission from the working face = the absolute gas emission from the goaf + the absolute gas emission during the stable gas release stage of the coal wall; S42, then the absolute gas emission rate Q in the goaf area 采空区绝 The calculation formula is: Q 采空区绝 =Q 停产工作面 -Q 煤壁绝 = Q(T 3停产 -T 1停产 ) / 100- Q 煤壁绝 ; Among them, Q 采空区绝 The absolute gas emission rate in the goaf is given in m. 3 / min; Q 停产工作面 For coal mining and coal discharge stoppage time exceeding T 煤壁稳定 Gas emission rate at working face, m 3 / min; Q 煤壁绝 The absolute gas emission rate during the stable gas release phase of the coal face, in m 3 / min; Q is the return air volume, m 3 / min; T 3停产 For coal mining and coal discharge stoppage time exceeding T 煤壁稳定 At that time, the gas concentration monitored by probe T3 was %; T 1停产 For coal mining and coal discharge stoppage time exceeding T 煤壁稳定 At that time, the gas concentration monitored by probe T1 was %.

5. The quantitative coal mining control system for preventing coal mine gas exceedances as described in claim 4, characterized in that: The prediction calculation formula of the coal mining gas emission prediction unit is as follows: Q 采煤绝 =Q 相 *(B 截深 *V 采煤 *H 采煤 *ρ 煤 ); Among them, Q 采煤绝 The absolute gas emission rate during coal mining by the coal mining machine is expressed in m. 3 / min; Q 相 The relative gas emission rate of coal, m 3 / t;B 截深 V represents the cutting depth of the coal mining machine, in meters. 采煤 H represents the cutting speed of the coal mining machine, in m / min. 采煤 ρ is the cutting height of the coal mining machine, in meters (m); 煤 The bulk density of coal, t / m³ 3 .

6. The quantitative coal mining control system for preventing coal mine gas exceedances as described in claim 5, characterized in that: The prediction operation of the coal gas emission prediction unit includes the following steps: S61. When the coal mining machine stops mining and the coal is being discharged normally at the tail of the support, the formula for calculating the absolute gas emission rate during coal discharge at the tail of the support is as follows: Q 放绝1 = Q(T 3停产 -T 1停产 ) / 100- Q 煤壁绝 - Q 采空区绝 ; Among them, Q 放绝1 The absolute gas emission rate at the tail of the support when the coal mining machine is stopped, in m. 3 / min; Q is the return air volume, m 3 / min; Q 煤壁绝 The absolute gas emission rate during the stable gas release phase of the coal face, in m 3 / min; Q 采空区绝 The absolute gas emission rate in the goaf is given in m. 3 / min; S62. Under normal mining conditions and normal coal discharge at the tail of the support, the formula for calculating the absolute gas emission rate of the unstable coal wall is: Q 非稳煤壁 = QC 非稳煤壁 / 100; Among them, Q 非稳煤壁 The absolute gas emission rate of an unstabilized coal face, in m 3 / min; Q is the return air volume, m 3 / min; C 非稳煤壁 The methane concentration during the unsteady coal face methane release phase is % (%). S63. Under normal coal mining conditions and normal coal discharge at the tail of the support, the formula for calculating the absolute gas emission rate during coal discharge at the tail of the support is as follows: Q 放绝1 = Q(T 3停产 -T 1停产 ) / 100- Q 非稳煤壁 - Q 采空区绝 ; Among them, Q 放绝1 The absolute gas emission rate at the tail of the support when the coal mining machine is stopped, in m. 3 / min; Q is the return air volume, m 3 / min; Q 非稳煤壁 The absolute gas emission rate of an unstabilized coal face, in m 3 / min; Q 采空区绝 The absolute gas emission rate in the goaf is given in m. 3 / min; S64. Draw a scatter plot of the number of coal outlets and the amount of coal gas emitted, and fit the function relationship between the number of coal outlets and the amount of coal gas emitted: q=mn 2 +kn+a; Where q is the amount of gas emitted during coal blasting, and m 3 / min; n is the number of coal outlets; m, k, and a are constants.

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