Method for determining management limit value of respirable dust concentration of fully mechanized coal mining face

Abstract

The invention relates to a fully mechanized coal mining face respirable dust concentration management limit value determination method, belongs to the technical field of coal mine dust treatment, and is used for solving the problem of inaccurate respirable dust control caused by the fact that a traditional fixed threshold value cannot adapt to a multi-dust-source coupling working condition. The method comprises the following steps: acquiring dust falling efficiency data of multiple dustproof measures, establishing a mathematical model of dustproof parameters and dust concentration, calculating a dynamic management limit value by combining an industrial standard threshold value, and performing self-adaptive adjustment by monitoring and triggering parameters such as spraying pressure and dust removal air volume in real time. Compared with a traditional method, the dynamic limit value enables the respirable dust concentration to be reduced by 40% or above, the multi-measure cooperative dust falling efficiency is improved to 85%, water is saved by 15%-20%, the equipment energy consumption is reduced by 10%, and intelligent and precise dust treatment is achieved.

Description

Technical Field

[0001] This invention belongs to the field of coal mine dust control technology, and relates to a method for determining the management limit of respirable dust concentration in fully mechanized mining faces. Background Technology

[0002] During the production process of fully mechanized coal mining faces, operations such as coal cutting by coal mining machines and the movement of hydraulic supports generate a large amount of respirable dust. Respirable dust particles are small in size and have a long suspension time, making them easily inhaled into the lungs of workers, leading to occupational health hazards such as pneumoconiosis. Currently, coal mines generally use total dust concentration as a monitoring indicator, but real-time online detection technology for respirable dust is not yet mature, resulting in a lack of precise control measures for dust control. Furthermore, existing dust concentration management limits mostly use fixed thresholds, failing to consider the dynamic impact of different dust control equipment operating parameters on dust reduction efficiency, making it difficult to adapt to the dust control needs under complex working conditions.

[0003] Traditional dust control systems often rely on single dust suppression methods, such as spray dust suppression or dust collector purification. However, when multiple dust sources are coupled together, such as coal cutting by mining machines and support movement, the dust diffusion path becomes complex, making it difficult to effectively control the concentration of respirable dust in the work area through static management limits. In existing spray dust suppression technologies, the nozzle range, atomization parameters, and dust transport patterns are not well-matched, and the water supply pressure regulation is lagging, resulting in large fluctuations in dust suppression efficiency. Furthermore, the low level of intelligence in hydraulic support dust suppression devices prevents them from adaptively adjusting the blocking range according to changes in mining height, further weakening the dust control effect.

[0004] To address the aforementioned issues, existing technologies have not yet proposed a solution that integrates multi-source dust sensing, dynamic limit calculation, and intelligent control, thus hindering the improvement of dust control at fully mechanized mining operations. Therefore, there is an urgent need to develop a method for determining respirable dust concentration management limits based on real-time dust source tracing and multi-measure synergistic control, enabling dynamic and precise control of dust management. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a method for determining the management limit of respirable dust concentration in fully mechanized mining faces.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] The method for determining the management limit for respirable dust concentration in fully mechanized mining faces includes the following steps:

[0008] S1. Obtain dust reduction efficiency data of multiple dust control measures at the longwall mining face under different combinations of process parameters;

[0009] S2. Based on the dust reduction efficiency data, test the real-time value of respirable dust concentration in the personnel working area under the corresponding combination of process parameters;

[0010] S3. Establish a mathematical model of the dust control system's regulation parameters and the concentration of respirable dust, wherein the mathematical model is expressed as:

[0011]

[0012] Where C is the predicted respirable dust concentration, C0 is the baseline concentration without dust control measures, and η1 to η n The dust reduction efficiency of each dust control measure;

[0013] S4. Based on the industry standard respirable dust concentration threshold, determine the optimal combination of process parameters that satisfies C≤th threshold, and calculate the dynamic management limit of respirable dust concentration based on the efficiency of each dust control measure corresponding to the optimal parameter combination.

[0014] Furthermore, the multiple dust control measures include at least two of the following: intelligent spray dust suppression on the coal mining machine, dust blocking by hydraulic supports, purification by onboard dust collectors, and dust capture by water film nets in the roadway.

[0015] Furthermore, in S1, the different combinations of process parameters include:

[0016] The spray pressure P and the number of open nozzles N of the coal mining machine's spray system;

[0017] The extension angle θ and slide rail displacement L of the hydraulic support dustproof device;

[0018] The air volume Q and the number of filter layers k of the airborne dust collector.

[0019] Furthermore, the dust reduction efficiency η of the coal mining machine spray system is calculated using the following formula:

[0020]

[0021] Where U is the relative velocity between droplets and dust, Q is the droplet volumetric flow rate, x is the effective spray length, and D... v Let d be the droplet size, A be the cross-sectional area of ​​the spray zone, B0 be the experimental constant, B be the Cunningham slip correction factor, and d be the droplet diameter. p ρ is the particle size of the dust. p For dust density, μ g This represents the gas dynamic viscosity.

[0022] Furthermore, in S2, the dust concentration at the breathing zone height is collected in real time by distributed dust sensors, and the start / stop status and parameter configuration of each dust prevention measure are recorded.

[0023] Furthermore, in S4, the calculation of the dynamic management limit includes:

[0024] When the efficiency of a single dust prevention measure is η iWhen the concentration is ≥ the preset threshold, the corresponding limit for respirable dust concentration is reduced by 10% to 15%;

[0025] When the efficiency of multi-measure coordination At that time, the limit for respirable dust concentration was adjusted to 50% to 60% of the industry standard.

[0026] Furthermore, it also includes S5: comparing the dynamic management limit with the real-time monitored respirable dust concentration; if the real-time value exceeds the limit, triggering adaptive adjustment of the dust control system parameters, the adjustment logic including:

[0027] Increase the spray pressure of the coal mining machine or open the number of nozzles;

[0028] Increase the coverage area of ​​the dustproof device for hydraulic supports;

[0029] Increase the air volume handled by the airborne dust collector.

[0030] Furthermore, the adaptive adjustment is achieved through a multi-objective optimization algorithm, with optimization objectives including: maximizing dust reduction efficiency, minimizing water consumption, and minimizing equipment power consumption.

[0031] Furthermore, the industry standard respirable dust concentration threshold is a time-weighted average concentration of 2.5 mg / m³. 3 The dynamic management limit is set to 70% to 90% of the threshold.

[0032] An electronic device includes a processor and a memory, the memory storing a computer program that, when executed by the processor, implements the method for determining the management limit of respirable dust concentration.

[0033] The beneficial effects of this invention are as follows:

[0034] (1) By establishing a mathematical model of the dust control system's regulation parameters and respirable dust concentration, and combining real-time dust reduction efficiency data and industry standard thresholds, management limits are dynamically calculated, solving the problem that traditional fixed thresholds cannot adapt to the coupled effects of multiple dust sources such as coal cutting by coal mining machines and support movement. Based on the mathematical model... The synergistic effect of different dust control measures on dust concentration suppression can be quantified, allowing management limits to be dynamically optimized according to process parameters. For example, when the synergistic efficiency of multiple measures reaches 70%, the management limit can be adjusted to 50%–60% of the industry standard, significantly improving dust control accuracy.

[0035] (2) Based on the optimized design of the dust suppression efficiency formula for coal mining machine spray, the dust suppression efficiency can be increased by 20% to 30% by adjusting parameters such as spray pressure and number of nozzles. For example, when the spray pressure is increased to 2.5 MPa and the number of open nozzles is increased to 4 sets, the relative velocity U between droplets and dust increases to 1.2 m / s, combined with the droplet size D vOptimized to 50μm, the dust reduction efficiency η is increased from 60% of the traditional method to 85% (supported by laboratory test data in the technical briefing materials).

[0036] (3) By using distributed dust sensors to monitor dust concentration in the breathing zone in real time, and combined with adaptive adjustment logic, parameter adjustments can be triggered within 5 seconds after the dust concentration exceeds the limit. For example, when the detected respirable dust concentration exceeds 1.2 times the dynamic limit, the system automatically increases the air volume Q of the airborne dust collector to 180m³. 3 / min, and in conjunction with the increase of the coverage of the hydraulic support dustproof device, so that the dust concentration drops back to below the safe threshold within 30 seconds (verified by on-site test data in the technical briefing materials).

[0037] (4) The multi-objective optimization algorithm balances dust reduction efficiency, water consumption, and equipment power consumption, reducing spray water consumption by 15%–20% and overall equipment energy consumption by more than 10% while ensuring dust control effectiveness. For example, after the coal mining machine spray pressure is intelligently adjusted from 3.0 MPa to 2.2 MPa, daily water savings can reach 8 m³. 3 (Water-saving rate calculation results in the technical briefing materials).

[0038] (5) The electronic equipment implementation method is programmed, which supports seamless integration with the existing intelligent system in the mine and can be extended to other dust control scenarios (such as tunneling faces), reducing the cost of promotion and application by more than 30%.

[0039] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0040] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0041] Figure 1 This is a flowchart of the present invention. Detailed Implementation

[0042] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed 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 are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0043] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0044] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0045] Figure 1 A flowchart illustrating the method for determining the management limit of respirable dust concentration in a fully mechanized mining face, as provided in an embodiment of the present invention.

[0046] Figure 1 Includes the following steps:

[0047] Data Acquisition and Dust Suppression Efficiency Acquisition (S1): The dust suppression efficiency data of coal mining machine spray, hydraulic support barrier, on-board dust collector and other dust prevention measures under different process parameter combinations are acquired through experiments and sensors.

[0048] Real-time test of respirable dust concentration (S2): The respirable dust concentration in the personnel's work area is monitored in real time using distributed dust sensors, and the operating status and parameter configuration of each dust prevention measure are recorded.

[0049] Mathematical Model Construction (S3): Based on dust reduction efficiency data, a mathematical relationship model is established between the dust control system regulation parameters and the concentration of respirable dust. The formula is as follows:

[0050]

[0051] Where C is the predicted respirable dust concentration, C0 is the baseline concentration without dust control measures, and η1 to η n The dust reduction efficiency of each dust control measure;

[0052] Dynamic management limit calculation (S4): Combined with industry standard thresholds (e.g., 2.5 mg / m³) 3 By solving the mathematical model in reverse, the optimal combination of process parameters that satisfy the concentration constraint is determined, and dynamic management limits (such as 50% to 90% of the threshold) are generated.

[0053] Real-time monitoring and closed-loop control: The concentration of respirable dust is continuously monitored by sensors. If the real-time value exceeds the dynamic limit, the dust control system parameters are automatically adjusted (such as increasing the spray pressure and increasing the dust removal air volume), and the results are fed back to the mathematical model to update the predicted value, forming a closed-loop control logic.

[0054] Example 1: Determination and Control of Dynamic Management Limits Based on Mathematical Models

[0055] Workflow:

[0056] 1. Multi-source data acquisition:

[0057] Distributed dust sensors (model KJ328-FC, spacing 10m, height 1.5m) were installed on the longwall mining face to collect real-time dust concentration data in the breathing zone.

[0058] The operating parameters of the coal mining machine are collected by the PLC controller: drum speed 15 rpm, traction speed 3.5 m / min, spray pressure 2.8 MPa, and 4 sets of nozzles (model BETE TF-6) are opened.

[0059] Parameters of the hydraulic support dustproof device: slide rail displacement L = 1.2m, extension angle θ = 50°, top plate pressure sensor reading p = 35MPa.

[0060] 2. Calculation of dust reduction efficiency model:

[0061] Calculate the spray efficiency of the coal mining machine:

[0062]

[0063] The dustproof efficiency of the hydraulic support was measured to be η = 68% through laboratory simulation.

[0064] 3. Dynamic limit generation:

[0065] Base concentration C0 = 5.0 mg / m³ 3 (Measured value without dust control measures), predicted concentration calculated based on mathematical model:

[0066] C=5.0×(1-0.82)×(1-0.68)=0.29mg / m 3

[0067] Combined with the industry standard threshold of 2.5 mg / m³ 3 The dynamic management limit is set at 50% of its value (i.e., 1.25 mg / m²). 3 ).

[0068] 4. Real-time control and verification:

[0069] When the sensor detects a respirable dust concentration C = 1.4 mg / m³ 3 (Exceeding the limit by 12%), the system will automatically trigger:

[0070] The spray pressure of the coal mining machine was increased to 3.2 MPa, the number of nozzles opened increased to 5 sets, and η increased to 86%.

[0071] The displacement of the hydraulic support slide rail was adjusted to L = 1.5m, and η was increased to 72%.

[0072] Predicted concentration after regulation:

[0073] C=5.0×(1-0.86)×(1-0.72)=0.20mg / m 3

[0074] The on-site measured concentration dropped to 0.22 mg / m³. 3 The error rate is <10%.

[0075] Technical effects:

[0076] Respirable dust concentration is reduced by 82% compared to traditional fixed limits, and water saving rate is 19% (spray flow rate from 12m). 3 / h decreased to 9.7m 3 / h).

[0077] The dynamic limit calculation model has a prediction accuracy of over 90%, and the data is based on the results of three repeated tests at Zhangjiamao Coal Mine (standard deviation σ = 0.03).

[0078] Example 2: Optimization of Coal Mining Machine Spray Parameters and High-Efficiency Dust Suppression

[0079] Workflow:

[0080] 1. Laboratory simulation test:

[0081] A 1:10 scale model of the fully mechanized mining face was constructed with a wind speed of 1.2 m / s and a dust concentration C0 of 8.0 mg / m³. 3 .

[0082] Testing different combinations of spray parameters:

[0083] Option A: Pressure 2.0 MPa, 3 sets of nozzles, droplet size D v =80μm, and η = 58% was measured.

[0084] Option B: Pressure 2.8MPa, 4 sets of nozzles, D v =50μm, and η = 82% was measured.

[0085] Option C: Pressure 3.5MPa, 6 sets of nozzles, D v =30μm, and η = 88% was measured.

[0086] 2. Parameter optimization and verification:

[0087] Choosing option B as the optimal parameter (balancing efficiency and energy consumption), we substitute it into the formula to verify:

[0088]

[0089] The error rate is less than 1%, and the model's reliability has been verified.

[0090] 3. Downhole Implementation and Results:

[0091] Real-time monitoring of parameter B in the deployment plan for the 14205 fully mechanized mining face of Zhangjiamao Coal Mine shows:

[0092] The concentration of respirable dust at 10m downwind of the coal mining machine was 2.8mg / m³. 3 Reduced to 0.5 mg / m³ 3 The dust reduction efficiency is 82.1%.

[0093] Spray water consumption increased from 15m³ per day 3 Reduced to 12.3m 3 (Water saving 18%), equipment power increased from 18kW to 22kW (the increase is controllable).

[0094] Technical effects:

[0095] The dust reduction efficiency is 41% higher than that of traditional methods. The data is based on the comparison between the scaled-down model and the actual underground measurement (confidence level p<0.05).

[0096] The water saving rate and energy consumption data were verified by the mine's water and electricity metering system, with an error of <3%.

[0097] Example 3: Adaptive Adjustment and Dust Barrier of Hydraulic Support Dustproof Device

[0098] Workflow:

[0099] 1. Height dynamic sensing and device adjustment:

[0100] The hydraulic support top beam height sensor (model KJ381-H) monitors the mining height H=7.2m in real time (design range 6~8m).

[0101] The sliding rail displacement of the dust prevention device is automatically adjusted to L = 1.3 m (calculation formula: L = 0.2H - 0.2), and the inclination angle of the dust receiving trough is adjusted to 47° (greater than the coal dust repose angle of 42°).

[0102] 2. Dust barrier efficiency test:

[0103] When the dust prevention device is not enabled, the dust leakage rate Q1 = 3.5 g / s during the support moving process.

[0104] After the adaptive device is enabled, the leakage rate Q2 = 0.8 g / s, and the barrier efficiency η = (3.5 - 0.8) / 3.5 = 77%.

[0105] 3. Intelligent maintenance and backwashing:

[0106] When the differential pressure sensor detects that the differential pressure Δp before and after the filter screen is ≥ 200 Pa, the backwashing spray is triggered (pressure 0.8 MPa, duration 10 s).

[0107] After backwashing, the differential pressure returns to Δp = 50 Pa, and the filter screen clogging period is extended from 8 h to 24 h. <​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​

[0119] The spray pressure of the coal mining machine was increased from 2.8MPa to 3.2MPa, and the number of nozzles opened increased from 4 to 6.

[0120] The displacement of the slide rail of the dustproof device of the hydraulic support is adjusted to L=1.5m, and the inclination angle of the dust collection trough is adjusted to 50°.

[0121] Airborne dust collectors can handle air volumes from 180m³ 3 / min increased to 220m 3 / min.

[0122] 3. Real-time effect verification:

[0123] Within 30 seconds of adjustment, the respirable dust concentration decreased from 1.8 mg / m³. 3 Reduced to 0.7 mg / m³ 3 The dust reduction efficiency is 61%.

[0124] Multi-measure synergy efficiency η total =1-(0.7 / 5.0)=86% (Base concentration C0=5.0mg / m³) 3 ).

[0125] Technical effects:

[0126] The dust concentration compliance rate under multi-source coupled operating conditions increased from 65% to 92%.

[0127] Response time ≤ 30 seconds, improving efficiency by 80% compared to manual control.

[0128] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for determining the management limit of respirable dust concentration in fully mechanized mining faces, characterized in that: Includes the following steps: S1. Obtain dust reduction efficiency data of multiple dust control measures at the longwall mining face under different combinations of process parameters; S2. Based on the dust reduction efficiency data, test the real-time value of respirable dust concentration in the personnel working area under the corresponding combination of process parameters; S3. Establish a mathematical model of the dust control system's regulation parameters and the concentration of respirable dust, wherein the mathematical model is expressed as: Where C is the predicted respirable dust concentration, C0 is the baseline concentration without dust control measures, and η1 to η n The dust reduction efficiency of each dust control measure; S4. Based on the industry standard respirable dust concentration threshold, determine the optimal combination of process parameters that satisfies C≤th threshold, and calculate the dynamic management limit of respirable dust concentration based on the efficiency of each dust control measure corresponding to the optimal parameter combination.

2. The method for determining the management limit of respirable dust concentration in a fully mechanized mining face according to claim 1, characterized in that: The multiple dust control measures include at least two of the following: intelligent spray dust suppression on coal mining machines, dust blocking by hydraulic supports, purification by onboard dust collectors, and dust collection by water film nets in roadways.

3. The method for determining the management limit of respirable dust concentration in a fully mechanized mining face according to claim 1, characterized in that: In S1, the different combinations of process parameters include: The spray pressure P and the number of open nozzles N of the coal mining machine's spray system; The extension angle θ and slide rail displacement L of the hydraulic support dustproof device; The air volume Q and the number of filter layers k of the airborne dust collector.

4. The method for determining the management limit of respirable dust concentration in a fully mechanized mining face according to claim 3, characterized in that: The dust reduction efficiency η of the coal mining machine's spray system is calculated using the following formula: Where U is the relative velocity between droplets and dust, Q is the droplet volumetric flow rate, x is the effective spray length, and D... v Let d be the droplet size, A be the cross-sectional area of ​​the spray zone, B0 be the experimental constant, B be the Cunningham slip correction factor, and d be the droplet diameter. p ρ is the particle size of the dust. p For dust density, μ g This represents the gas dynamic viscosity.

5. The method for determining the management limit of respirable dust concentration in a fully mechanized mining face according to claim 1, characterized in that: In S2, the dust concentration at the breathing zone height is collected in real time by distributed dust sensors, and the start / stop status and parameter configuration of each dust prevention measure are recorded.

6. The method for determining the management limit of respirable dust concentration in a fully mechanized mining face according to claim 1, characterized in that: In S4, the calculation of the dynamic management limit includes: When the efficiency of a single dust prevention measure is η i When the concentration is ≥ the preset threshold, the corresponding limit for respirable dust concentration is reduced by 10% to 15%; When the efficiency of multi-measure coordination At that time, the limit for respirable dust concentration was adjusted to 50% to 60% of the industry standard.

7. The method for determining the management limit of respirable dust concentration in a fully mechanized mining face according to claim 1, characterized in that: It also includes S5: comparing the dynamic management limit with the real-time monitored respirable dust concentration; if the real-time value exceeds the limit, triggering adaptive adjustment of the dust control system parameters, the adjustment logic including: Increase the spray pressure of the coal mining machine or open the number of nozzles; Increase the coverage area of ​​the dustproof device for hydraulic supports; Increase the air volume handled by the airborne dust collector.

8. The method for determining the management limit of respirable dust concentration in a fully mechanized mining face according to claim 7, characterized in that: The adaptive adjustment is achieved through a multi-objective optimization algorithm, with optimization objectives including maximizing dust reduction efficiency, minimizing water consumption, and minimizing equipment power consumption.

9. The method for determining the management limit of respirable dust concentration in a fully mechanized mining face according to claim 1, characterized in that: The industry standard threshold for respirable dust concentration is 2.5 mg / m³. 3 The dynamic management limit is set to 70% to 90% of the threshold.

10. An electronic device, characterized in that, It includes a processor and a memory, the memory storing a computer program that, when executed by the processor, implements the method for determining the management limit of respirable dust concentration as described in any one of claims 1 to 9.

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