A dust control and collection air purification method for a tunneling working face

Abstract

The application discloses a kind of tunneling working face dust control collection air purification method, the air purification method is based on tunneling working face dust control collection air purification system implementation, the air purification method includes: step S1, determines system optimal layout;Step S2, is divided to cutting area to fully mechanized excavation face;Step S3, based on the air supply distance and air leakage rate of air duct calculates air leakage volume Q of air duct, determines the end wind speed of pressure air duct;Step S4, numerical prediction is carried out to the wind speed and dust concentration of next time based on prediction model;Step S5, the end wind speed of pressure air duct is divided into interval, combined with multiple cutting areas to carry out working condition combination, obtain multi-working condition operation group;Step S6, determines optimal air flow control scheme.The intelligent control cabinet of the application adjusts the exhaust diameter and exhaust angle of air flow dust control device according to current working condition, and selects the optimal air flow control scheme to realize the intelligent adjustment of air flow control.

Description

Technical Field

[0001] This invention relates to the field of air purification technology at tunneling faces, and in particular to a method for dust control, collection, and air purification at tunneling faces. Background Technology

[0002] As a major coal producer, China has seen its annual coal output repeatedly reach new highs with the improvement of automation and intelligence in mining machinery. However, the application of large-scale tunneling machinery has also brought about problems such as increased dust generation and higher dust concentrations; currently, the highest dust concentration at the tunneling working face can exceed 1000 mg / m³. 3 Excessive dust concentration can easily lead to explosions. Fine dust is difficult to settle and collect, and it spreads backward with the airflow, causing even more serious harm to the human body. High concentrations of dust can also induce occupational pneumoconiosis in miners. Therefore, ventilation and dust suppression at the fully mechanized tunneling face plays a crucial role in coal mine safety and protecting the health and lives of workers. However, current traditional tunneling face ventilation systems still use constant airflow ventilation and dust suppression methods, which cannot make precise and intelligent control of airflow direction, speed, and other airflow states according to actual working conditions. This results in the inability to effectively control dust at the front end of the roadway and prevent dust from drifting backward. Moreover, the escaped small dust particles spread backward and are not easy to settle, which can easily lead to excessively high concentrations of respirable dust in areas where personnel are active. Therefore, it is necessary to design a controlled collection and removal air purification method. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for dust control, collection, removal, and air purification in tunneling working faces. The airflow dust control device is connected to an intelligent control cabinet. The intelligent control cabinet adjusts the exhaust port diameter and exhaust angle of the airflow dust control device according to the current working conditions, selects the optimal airflow control scheme to adjust the airflow dust control device, and realizes intelligent adjustment of airflow control.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is: a method for controlling, collecting, removing, and purifying air at a tunneling face. The air purification method is based on a dust control, collection, and air purification system at the tunneling face, and includes the following steps: Step S1, determining the optimal system layout; Step S2, dividing the tunneling face into cut-off areas; Step S3, calculating the air leakage Q of the ventilation duct based on the air supply distance and leakage rate, and determining the wind speed at the end of the compressed air duct; Step S4, numerically predicting the wind speed and dust concentration at the next moment based on a prediction model; Step S5, dividing the wind speed at the end of the compressed air duct into intervals, combining multiple cut-off areas to form a multi-condition work group; Step S6, determining the optimal airflow control scheme based on a gas-solid-liquid three-phase coupling calculation model combined with the multi-condition work group.

[0005] Preferably, the cutting area is divided into an upper cutting area, a middle cutting area, and a lower cutting area based on the tilt angle of the boom obtained in real time by the tilt angle sensor on the cutting boom of the integrated tunneling and anchoring machine; with the horizontal cutting wall as 0º, the tilt angle of the cutting boom in the upper cutting area is not less than 15º, the tilt angle of the cutting wall in the middle cutting area is in the range of -20º to 15º, and the tilt angle of the cutting boom in the lower cutting area is not greater than -20º.

[0006] Preferably, the air leakage Q of the duct is expressed by the following formula:

[0007]

[0008] In the formula: m is the compressed air volume without loss, taken as... I represents the number of local ventilation units, which is set to 1; L represents the ventilation distance. This refers to the air leakage rate.

[0009] Preferably, the prediction model is expressed by the following formula:

[0010]

[0011]

[0012] In the formula: Let t be the predicted wind speed at time t+h based on historical monitoring data. Let t be the predicted dust concentration at time t+h based on historical monitoring data. This represents the smoothed horizontal term of the wind speed sequence at time t; This represents the smoothing level term of the dust concentration sequence at time t; For the trend update term of the wind speed series at time t, is the trend update term for the dust concentration sequence at time t; h is the prediction step size.

[0013] Preferably, the dust control and collection air purification system includes: an airflow dust control device, a two-stage dust collection device, an air curtain dust isolation device, a wet dust removal device, and a dust control and collection intelligent monitoring device. The airflow dust control device is installed at the air outlet of the telescopic duct. The two-stage dust collection device is arranged along the length of the telescopic duct and parallel to the telescopic duct. The air curtain dust isolation device has a U-shaped structure and is installed between the two-stage dust collection device and the wet dust removal device. The wet dust removal device is connected to the end of the exhaust duct by an adapter. The dust control and collection intelligent monitoring device is installed on the right rear side of the tunneling and anchoring machine.

[0014] Preferably, the airflow dust control device includes an air outlet, a diameter adjustment unit, and a direction adjustment unit. The air outlet is located at the front end of the air outlet of the telescopic air duct. The diameter adjustment unit is located on the outside of the air outlet to facilitate adjustment of the air outlet diameter. The direction adjustment unit is located on the lower side of the air outlet to facilitate adjustment of the air outlet direction.

[0015] Preferably, the two-stage dust collection device includes a primary dust collection port, a secondary dust collection port, and an exhaust duct. Both the primary and secondary dust collection ports are rectangular structures. The primary dust collection port is located at the top front end of the tunneling and anchoring machine, and the secondary dust collection port is located at the rear of the tunneling and anchoring machine on the return air side. The primary and secondary dust collection ports are connected by the exhaust duct to achieve two-stage dust collection.

[0016] Preferably, the air curtain dust separation device has a U-shaped structure, and multiple exhaust ports are provided circumferentially on the outer side of the air curtain dust separation device to facilitate the outward spraying of airflow. The air curtain dust separation device is located between the secondary dust collection port and the wet dust removal device to form an air damper.

[0017] Preferably, the wet dust removal device is located above the belt conveyor and supported by an installation trolley, and the wet dust removal device is connected to the end of the exhaust duct via an adapter.

[0018] Preferably, the dust control and intelligent monitoring device includes a data acquisition unit and an intelligent control cabinet. The data acquisition unit is connected to the intelligent control cabinet, which includes a cabinet body and a PLC controller. The PLC controller is installed inside the cabinet. The data acquisition unit includes a dust sensor, a wind speed sensor, and a tilt sensor. The tilt sensor is installed on the cutting wall of the tunneling and anchoring machine to facilitate real-time acquisition of the boom tilt angle. There are multiple dust sensors and wind speed sensors. The multiple dust sensors detect the dust concentration at different locations and transmit the data to the PLC controller. The multiple wind speed sensors detect the wind speed at different locations and transmit the data to the PLC controller.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] 1. The airflow dust control device of the present invention is connected to an intelligent control cabinet. The intelligent control cabinet adjusts the exhaust port diameter and exhaust angle of the airflow dust control device according to the current working conditions, selects the optimal airflow control scheme to adjust the airflow dust control device, and realizes intelligent adjustment of airflow control.

[0021] 2. This invention uses a dust control device, a two-stage dust collection device, and an air curtain dust isolation device to capture dust. By adjusting the outlet diameter and exhaust angle of the dust control device, the dust is controlled at the front end of the roadway. The two-stage dust collection device captures the dust, and the air curtain dust isolation device intercepts small dust particles and causes them to drift backward. This significantly reduces the dust concentration at the driver's breathing section and the pedestrian's breathing section on the return air side, resulting in a significant dust reduction effect.

[0022] 3. This invention constructs a time-series prediction model of wind speed and dust concentration, which can predict the changes in dust concentration in future periods based on historical monitoring data, match the optimal airflow control scheme in advance, realize proactive dust control, and make up for the shortcomings of traditional ventilation and dust reduction response lag.

[0023] 4. This invention establishes a two-dimensional full-condition division system of cutting area and wind speed range, matching exclusive airflow control parameters for various operating scenarios, covering the entire tunneling operation process, and effectively improving the system's adaptability to complex underground working conditions.

[0024] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0026] Figure 2 for Figure 1 Top view;

[0027] Figure 3 for Figure 1 Side view;

[0028] Figure 4 This is a flowchart of the prediction algorithm for the wind speed and dust prediction and evaluation method of the present invention;

[0029] Figure 5 This is a diagram showing the flow field transport and distribution characteristics of the air purification system of the present invention at the tunneling face.

[0030] Explanation of reference numerals in the attached figures:

[0031] Detailed Implementation

[0032] Example 1

[0033] like Figures 1 to 3 As shown, this invention discloses a method for controlling, collecting, and purifying air at a tunneling working face. The air purification method is implemented based on a dust control, collection, and air purification system at the tunneling working face, and includes:

[0034] Step S1: Determine the optimal system layout;

[0035] A gas-solid-liquid three-phase coupling calculation model was established at the tunneling face to analyze the spatiotemporal evolution of the dust field. Based on the wind speed distribution characteristics of the roadway in the high-concentration dust hazard area and the personnel activity pollution area under different working conditions, the optimal spatial layout of the airflow dust control device 1, the two-stage dust collection device 2, the air curtain dust isolation device 3, the wet dust removal device 4, and the dust control, collection, and removal intelligent monitoring device was determined.

[0036] This model is a professional numerical simulation model built for dust control scenarios in coal mine tunneling faces. It focuses on the transport and interaction of three types of media within the tunnel: gaseous airflow, solid dust, and liquid droplets. The gas-solid-liquid three-phase coupled calculation model includes an airflow calculation module, a dust droplet calculation module, and a central control module. Both the airflow and dust droplet calculation modules are communicatively connected to the central control module for data processing. The central control module uses the CFD-DEM coupling method to achieve coupled simulation calculations of the three-phase media and utilizes Fluent's Realizable feature. The k-ɛ turbulent diffusion model ensures the accuracy and precision of the calculations. The airflow calculation module employs a semi-implicit method (SIMPLEC) for the pressure coupling equations. It discretizes and solves the momentum equations based on the assumed velocity and pressure fields, then solves the pressure correction equations, correcting and iterating the pressure and velocity until the flow field converges. The dust and droplet calculation module uses the JKP model in EDEM to calculate the inertial collisions, agglomeration, and sedimentation between the discrete phases of droplets and dust particles. Important parameters in the model are set to experimental calibration values. The central control module receives and processes the data sent by the airflow and dust / droplet calculation modules, applying the calculation results of the continuous phase to the particle phases of dust particles and droplets. This establishes a gas-solid-liquid three-phase coupled calculation model of airflow, dust, and droplets. This model is used to simulate and analyze the airflow and dust field transport patterns at the tunneling face. The data obtained from the underground test experiments are compared with the numerical simulation data to verify the accuracy of the model, thus improving the accuracy and precision of the model's calculations.

[0037] Step S2: Divide the tunneling face into sections;

[0038] When the boom of the tunneling and anchoring machine swings during coal cutting, the angle changes. Based on the boom tilt angle obtained in real time by the tilt sensor on the cutting boom of the tunneling and anchoring machine, the cutting area is divided into the upper cutting part, the middle cutting part and the lower cutting part.

[0039] With the horizontal angle of the cut wall defined as 0º, upward deviation as positive and downward deviation as negative, the cutting process is divided into:

[0040] Upper part cutting: Cutting arm inclination angle > 15º;

[0041] Mid-section cut: -20º < cut wall inclination angle < 15º;

[0042] Lower section cut: Cutting wall inclination angle < -20º;

[0043] That is, the inclination angle of the cutting arm at the top of the cut is not less than 15º, the inclination angle of the cutting wall in the middle of the cut is in the range of -20º to 15º, and the inclination angle of the cutting arm at the bottom of the cut is not greater than -20º.

[0044] Step S3: Calculate the air leakage Q of the air duct based on the air supply distance and leakage rate of the air duct, and determine the air velocity at the end of the compressed air duct;

[0045] Based on the tunneling face operation procedures, the maximum air supply distance and the air volume without loss of compressed air volume are determined. According to the air leakage rate comparison table of 100-meter ventilation ducts, the air leakage is calculated according to the maximum allowable air leakage rate for different distances. The air leakage Q of the ventilation duct is expressed by the following formula:

[0046] (1)

[0047] In the formula: m is the compressed air volume without loss, taken as... I represents the number of local ventilation units, which is set to 1; L represents the ventilation distance. This refers to the air leakage rate.

[0048] The air leakage rate per 100 meters of ventilation duct should meet the following requirements, as shown in Table 1:

[0049] Table 1. Comparison of air leakage rates for 100-meter ventilation ducts

[0050]

[0051] By calculating the actual wind speed at the end of the duct under different air supply distances, the reasonable range of wind speed variation at the end is determined to be 5-12 m / s. This reasonable range of wind speed variation is taken as the wind speed range at the end of the air compressor duct, and the speed range of 5-12 m / s is divided into 7 working conditions at equal intervals, which provides a basis for exploring the relationship between air volume and wind speed and constructing a multi-working-condition intelligent control scheme.

[0052] Step S4: Based on the prediction model, make numerical predictions of wind speed and dust concentration at the next moment;

[0053] Based on single-point threshold evaluation, a comprehensive judgment is made by combining working condition information such as cutting position and distance from the face, so as to realize the quantitative evaluation and over-limit warning of wind speed and dust concentration at multiple measuring points in the tunneling face.

[0054] The predictive model is installed in the intelligent control cabinet 5 for data monitoring and trend prediction, accurately matching the experimental scheme corresponding to the current working condition, so that the offline parameters are adapted to the real flow field state on site and transformed into the optimal control scheme that can be directly executed.

[0055] Multiple sets of wind speed sensors 6 and dust sensors 7 are deployed at different locations in the tunnel face to simultaneously collect data from each measuring point, as well as working condition information such as the cutting position and distance from the face, and summarize the data to the intelligent control cabinet 5. The intelligent control cabinet 5 uses preset wind speed and dust concentration classification thresholds as a benchmark to complete the single-point level determination of each measuring point, and dynamically corrects the evaluation criteria in combination with the cutting position and distance from the face. After weighted integration of multiple measuring points, the overall quantitative evaluation result of the working face is output. Real-time alarms of the corresponding level are triggered based on the evaluation results. At the same time, the concentration change is predicted by the prediction model. If the predicted concentration is too high, an early warning is triggered in advance.

[0056] The prediction expression of the prediction model is represented by the following formula:

[0057] (2)

[0058] (3)

[0059] In the formula: Let t be the predicted wind speed at time t+h based on historical monitoring data. Let t be the predicted dust concentration at time t+h based on historical monitoring data. This represents the smoothed horizontal term of the wind speed sequence at time t; This represents the smoothing level term of the dust concentration sequence at time t; This represents the trend update term for the wind speed sequence at time t; is the trend update term for the dust concentration sequence at time t; h is the prediction step size.

[0060] The smoothed horizontal term of the wind speed sequence at time t It can be expressed as follows:

[0061] (4)

[0062] In the formula: This represents the actual observed wind speed at the current moment; This is the horizontal smoothing coefficient, taking a value between 0 and 1. The larger the value, the more reliable the current observation. The smaller the value, the more reliable the prediction. Take 0.6;

[0063] Smoothing level term of dust concentration sequence at time t It can be expressed as follows:

[0064] (5)

[0065] In the formula: This represents the actual observed dust concentration at the current moment;

[0066] Trend update term of wind speed series at time t It can be expressed as follows:

[0067] (6)

[0068] In the formula: β is the trend smoothing coefficient, which takes a value between 0 and 1. The larger the β is, the faster the trend changes with the data, and the smaller the β is, the slower the trend changes with the data. We take β = 0.2. This represents the smoothed horizontal term of the wind speed sequence at time t-1; This represents the trend update term for the wind speed sequence at time t-1;

[0069] Trend update term of dust concentration sequence at time t It can be expressed as follows:

[0070] (7)

[0071] In the formula: This represents the smoothed level term of the dust concentration sequence at time t-1; This represents the trend update term for the dust concentration sequence at time t-1.

[0072] In use, the prediction module receives real-time wind speed and dust concentration data uploaded by wind speed sensor 6 and dust sensor 7, processes the data, and outputs the prediction results for future times. For initial application, the first observation data is used as the initial level, and the initial trend is estimated from the first two observations. That is, starting from t=2, recursion begins, accumulating several sets of observation samples. The prediction trend is estimated through multi-point, period-by-period trend changes. The number of prediction samples can be flexibly set according to the fluctuation characteristics of the field data. After the initial parameters are determined, iterative recursion is performed according to the smoothing level term and trend update term, outputting the prediction results corresponding to the step size, thereby ensuring the stability and accuracy of the prediction. Figure 4 As shown.

[0073] Step S5: Divide the air velocity at the end of the air compressor into intervals, combine multiple cutting areas to form a multi-condition operation group.

[0074] Using the change in wind speed at the end of the air compressor duct as the operating condition, with the wind speed at the end of the air compressor duct varying within the range of 5-12 m / s, the wind speed range at the end of the air compressor duct is divided into 7 operating conditions at equal intervals: 5-6 m / s, 6-7 m / s, 7-8 m / s, 8-9 m / s, 9-10 m / s, 10-11 m / s, and 11-12 m / s. Using the cutting area and the wind speed range at the end of the air compressor duct as the basis for determining the operating condition, the upper part of the cutting area, the middle part of the cutting area, the lower part of the cutting area, and the 7 wind speed ranges of 5-6 m / s, 6-7 m / s, 7-8 m / s, 8-9 m / s, 9-10 m / s, 10-11 m / s, and 11-12 m / s are fully combined to form 7*3=21 operating conditions, which facilitates the exploration of different control schemes under various operating conditions.

[0075] Step S6: Determine the optimal airflow control scheme based on the gas-solid-liquid three-phase coupling calculation model and the multi-condition operation group.

[0076] Using the deflection angle and diameter of the airflow dust control device as independent variables, and the dust concentration of workers on the compressed air side, return air side, tunneling operator, and anchor transfer unit operator as optimization objectives, a quantitative mapping relationship was established between the independent variables and multiple optimization objectives. The independent variables are two adjustable parameters of the airflow dust control device: one is the diameter of the air outlet, adjustable from 0.8 to 1.2 m; the other is the deflection angle of the air outlet, adjustable from 0 to 30°. These are input variables that can be actively adjusted and directly affect the flow field and dust distribution in the tunnel. Through multi-objective optimization using response surface methodology and a fitted regression model, the optimal control scheme for effectively reducing dust concentration under different operating conditions was finally obtained. This quantitative mapping relationship is the basis for airflow dust control. The quantitative functional correspondence between the outlet diameter and deflection angle of the device and the dust concentration optimization of four positions—compressed air side anchor bolt worker, return air side anchor bolt worker, tunneling operator, and anchor bolt transfer unit operator—was established. Specifically, this was achieved by constructing multiple sets of independent variable parameters using a central composite design (CCD), performing numerical simulations based on a gas-solid-liquid three-phase coupling calculation model to obtain the dust concentration results for each of the four positions under each set of parameters, and then using response surface methodology to fit and regress the data, constructing regression equations with outlet diameter and deflection angle as inputs and dust concentration at each position as outputs. This quantitatively characterizes the influence of changes in the two independent variables on the dust concentration at each position, providing a quantitative basis for subsequent multi-objective optimization to find the optimal control scheme.

[0077] The dust control and air purification system includes: an airflow dust control device 1, a two-stage dust collection device 2, an air curtain dust isolation device 3, a wet dust removal device 4, and a dust control and intelligent monitoring device. The airflow dust control device 1 is installed at the air outlet of the telescopic duct 9. The two-stage dust collection device 2 is arranged along the length of the telescopic duct 9 and is parallel to the telescopic duct 9. The air curtain dust isolation device 3 has a U-shaped structure and is installed between the two-stage dust collection device 2 and the wet dust removal device 4. The wet dust removal device 4 is connected to the end of the exhaust duct by a converter 10. The dust control and intelligent monitoring device is installed on the right rear side of the tunneling and anchoring machine.

[0078] The airflow dust control device 1 is installed at the air outlet of the telescopic ventilation duct 9 of the tunneling and anchoring machine. The telescopic ventilation duct 9 is supported by the ventilation duct bracket 11 and is securely connected to the tunneling and anchoring machine by the fixed bracket 12. The primary dust collection port 2-1 of the two-stage dust collection device 2 is the dust collection port of the on-board dust removal fan of the tunneling and anchoring machine. The secondary dust collection port 2-2 is located behind the tunneling and anchoring machine on the return air side. The primary dust collection port 2-1 and the secondary dust collection port 2-2 are connected by the exhaust duct 2-3. The wet dust collection device 4 is located above the belt conveyor and is supported by the installation trolley 8. It is connected to the end of the exhaust duct 2-3 by... The adapter 10 is connected, and the air curtain dust removal device 3 is installed between the wet dust removal device 4 and the secondary dust collection port 2-2 to facilitate the formation of an air damper by the jet airflow to prevent dust from spreading backward. The dust control and collection intelligent monitoring device includes a data acquisition unit and an intelligent control cabinet 5. The data acquisition unit includes a dust sensor 7, a wind speed sensor 6 and an angle sensor. The airflow dust control device 1 has a built-in wind speed sensor. The intelligent control cabinet 5 is installed on the right rear side of the tunneling and anchoring machine and is operated by the tunneling operator. The intelligent control cabinet 5 uses a PLC controller as the core of the device control.

[0079] The airflow dust control device 1 includes an air outlet, a diameter adjustment unit, and a direction adjustment unit. The air outlet is located at the front end of the air outlet of the telescopic air duct 9. The diameter adjustment unit is located on the outside of the air outlet to facilitate adjustment of the diameter of the air outlet. The direction adjustment unit is located on the lower side of the air outlet to facilitate adjustment of the direction of the air outlet.

[0080] The diameter adjustment unit includes a diameter adjustment component and a diameter change motor. The diameter adjustment component is located on the outside of the air outlet and connected to the air outlet. The diameter change motor drives the diameter adjustment component to move, and the diameter adjustment component drives the air outlet to adjust the size of the air outlet diameter. The direction adjustment unit includes a direction adjustment component and an angle deflection motor. The direction adjustment component is a worm gear. The angle deflection motor is connected to the worm gear to facilitate driving the worm gear to rotate. The worm gear drives the worm wheel to rotate, and the transmission shaft on the worm wheel drives the air outlet to deflect, thereby achieving the purpose of adjusting the air outlet direction. A front and rear displacement motor is also provided on the lower side of the air outlet to facilitate adjusting the distance between the air outlet and the head.

[0081] The two-stage dust collection device 2 includes a primary dust collection port 2-1, a secondary dust collection port 2-2, and an exhaust duct 2-3. Both the primary dust collection port 2-1 and the secondary dust collection port 2-2 are rectangular structures. The primary dust collection port 2-1 is located at the top front end of the tunneling and anchoring machine, and the secondary dust collection port 2-2 is located at the rear of the tunneling and anchoring machine on the return air side. The primary dust collection port 2-1 and the secondary dust collection port 2-2 are connected by the exhaust duct 2-3 to achieve two-stage dust collection.

[0082] The primary dust collection port 2-1 is located in front of the rubber baffle and is responsible for collecting the dust generated in the cutting area. The dust is then initially removed by the onboard dust removal fan. The secondary dust collection port 2-2 works with the airflow dust control device 1 to collect the dust overflowing from the baffle gaps and sends it to the wet dust removal device 4 through the exhaust duct 2-3 for deep purification. In other words, the primary dust collection port 2-1 is used to efficiently capture a large amount of dust in conjunction with the airflow dust control device 1. Smaller particles that are not sucked in are carried away from the head direction by the airflow and blocked by the air curtain dust separation device 3. They are then collected again through the secondary dust collection port 2-2.

[0083] The air curtain dust removal device 3 has a U-shaped structure. Multiple exhaust ports are provided circumferentially on the outer side of the air curtain dust removal device 3 to facilitate the outward spraying of airflow. The air curtain dust removal device 3 is located between the secondary dust collection port 2-2 and the wet dust removal device 4 to form an air damper.

[0084] To address the issue of large amounts of respirable dust generated at the tunneling face that are difficult to settle and collect, which poses a serious hazard to human health due to its backward diffusion with the airflow, an air curtain dust isolation device 3 is used to ensure that the wind speed at the end of the air curtain is not less than 2 m / s, forming an effective air damper to intercept respirable dust. The air curtain dust isolation device 3 is externally connected to a high-pressure air duct, which provides the air source. High-pressure air is delivered to the air curtain dust isolation device 3 through a rigid air inlet pipe, and high-pressure air is blown out through the exhaust ports set around the circumference of the air curtain dust isolation device 3, forming an adjustable air damper that effectively intercepts respirable dust and prevents the respirable dust from spreading backward.

[0085] The wet dust removal device 4 is located above the belt conveyor and is supported by the installation trolley 8. The wet dust removal device 4 is connected to the end of the exhaust duct 2-3 through the adapter 10.

[0086] The wet dust collector 4 is securely installed on the installation trolley 8. The wet dust collector 4 uses existing equipment for wet dust removal. The dust collected by the primary dust collection port 2-1 and the secondary dust collection port 2-2 reaches the wet dust collector 4 through the exhaust duct 2-3. The wet dust collector 4 performs wet dust removal and discharges clean gas.

[0087] The dust control and intelligent monitoring device includes a data acquisition unit and an intelligent control cabinet 5. The data acquisition unit is connected to the intelligent control cabinet 5. The intelligent control cabinet 5 includes a cabinet body and a PLC controller. The PLC controller is installed inside the cabinet body. The data acquisition unit includes a dust sensor 7, a wind speed sensor 6, and a tilt sensor. The tilt sensor is installed on the cutting wall of the tunneling and anchoring machine to facilitate real-time acquisition of the boom tilt angle. There are multiple dust sensors 7 and multiple wind speed sensors 6. The multiple dust sensors 7 detect the dust concentration at different locations and transmit the data to the PLC controller. The multiple wind speed sensors 6 detect the wind speed at different locations and transmit the data to the PLC controller.

[0088] There are three wind speed sensors (6) and three dust sensors (7), arranged in pairs to form three sensor groups to detect wind speed and dust concentration. These three sensor groups are sequentially located along the dust control and intelligent monitoring device from front to back at the primary dust collection port 2-1, the secondary dust collection port 2-2, and the side wall of the wet dust collector 4, facilitating real-time data acquisition of wind speed and dust concentration. An inclination sensor is installed on the cutting wall of the tunneling and anchoring machine, allowing it to monitor the cutting position by sensing changes in the angle of the cutting wall relative to the direction of gravity. The intelligent control cabinet 5 is installed on the right rear side of the tunneling and anchoring machine. The cabinet has a touchscreen for parameter setting and data querying. The PLC controller uses RS485 and industrial Ethernet for sensor data acquisition, operating condition identification, control scheme acquisition, and actuator driving functions. Figure 5 As shown.

[0089] Example 2

[0090] To address the existing problems at the tunneling face, and based on the existing equipment layout space obtained from the underground survey, the installation locations and space conditions of each dust control and collection device were determined. To achieve efficient dust control, single-parameter control experiments were conducted on the airflow dust control device and the two-stage dust collection device through data simulation to determine the optimal layout of the dust control and collection air purification system at the tunneling working face. The underground system was then installed and arranged to construct a complete closed loop from "dust source" to "control execution" and then to "dust control and reduction".

[0091] The optimal spatial layout is as follows: the airflow dust control device 1 is installed at the air outlet of the compressed air duct, 9m from the face of the project; the primary dust collection port 2-1 of the two-stage dust collection device 2 adopts the dust collection port of the airborne dust removal fan, and the secondary dust collection port 2-2 is located behind the tunneling and anchoring machine on the return air side, 8m from the face of the project; the wet dust removal device 4 is connected to the exhaust duct and installed on the belt conveyor, 20m from the face of the project; the air curtain dust isolation device 3 is installed between the wet dust removal device 4 and the secondary dust collection port 2-2, 12m from the face of the project.

[0092] The dust control and air purification system at the tunneling face includes an airflow dust control device 1, a two-stage dust collection device 2, an air curtain dust separation device 3, a wet dust collection device 4, and an intelligent dust control and collection monitoring device. The main parameters and installation locations of each device are as follows:

[0093] The airflow dust control device 1 is installed at the end of the air compressor. It changes the airflow state of the air outlet by changing the diameter and deflection angle of the air outlet. The air outlet diameter can be adjusted from 0.8 to 1.2 m, and the deflection angle can be adjusted from 0 to 30 º.

[0094] The two-stage dust collection device 2 includes a primary dust collection port 2-1 and a secondary dust collection port 2-2. Both the primary dust collection port 2-1 and the secondary dust collection port 2-2 are connected to the exhaust duct. The size of the dust collection port and the exhaust duct are designed according to the layout of the roadway equipment. The primary dust collection port 2-1 is 800mm long and 540mm wide, the secondary dust collection port 2-2 is 1200mm long and 860mm wide, the exhaust duct is a circle with a diameter of 800mm, and the thickness of the exhaust duct wall is 5mm.

[0095] The air curtain dust-proof device 3 is 200mm wide and 120mm high. The width of the exhaust port of the straight pipe section is 2mm and the width of the exhaust port of the bent pipe section is 3mm, which makes it easy to ensure that the wind speed at the end of the air curtain is not less than 2m / s, forming an effective air door to intercept respirable dust.

[0096] The wet dust collector 4 uses a mining wet dust collector, model KCS-500D, manufactured by Shandong Tianhe Technology Co., Ltd.

[0097] The dust control and intelligent monitoring device includes a data acquisition unit and an intelligent control cabinet 5. The data acquisition unit includes a wind speed sensor, a dust sensor, and an inclination sensor to achieve real-time acquisition of wind speed, dust concentration, and the inclination angle of the boom of the tunneling and anchoring machine. The inclination sensor monitors the position of the cutting wall by sensing the angle change of the cutting wall relative to the direction of gravity. The intelligent control cabinet 5 has a height of 500mm, a width of 450mm, and a thickness of 180mm. The cabinet is installed on the tunneling and anchoring machine. The PLC controller is installed inside the cabinet. The PLC controller processes the data to predict dust concentration and evaluate thresholds. The PLC controller combines real-time airflow and cutting position to identify the current working condition, which facilitates the determination of the optimal airflow control scheme and drives the airflow dust control device 1 to adjust the diameter and direction of the air outlet. The touch screen on the cabinet can display and identify the working condition, query historical data, manually control, and retrieve the scheme.

[0098] When dividing the cut-off area, the wind speed at the end of the air compressor duct is first calculated to determine the wind speed range. Then, the operating conditions are determined. Based on the operating conditions, the experimental platform determines the optimal intelligent airflow control scheme under different operating conditions. This experimental platform has two driving methods: manual driving and automatic program invocation. Manual driving is directly operated by the R&D personnel, while automatic program invocation involves using the Central Composite Design method to design and perform numerical simulations to acquire data. Then, Design-Expert software is used for response surface analysis. Response surface analysis establishes a quantitative mapping relationship between airflow control parameters, system layout parameters, and dust concentration indicators. The specific details of obtaining the optimal intelligent airflow control scheme under different operating conditions include:

[0099] The tunneling face is divided into three areas: upper section, middle section, and lower section. Based on the site conditions, the typical tunneling face has a tunneling height of 3.1m. The tunneling machine model is Sandvik EJM400 / 4-2 (MB670-1) roadheader. The angle corresponding to each section is calculated based on the boom of the roadheader and the tunneling face height. The tilt sensor is installed on the cutting arm. With the horizontal position of the cutting arm as 0º, upward deviation is positive and downward deviation is negative. When the tilt sensor reading is greater than 15º, it is the upper section; when the tilt sensor reading is between -20º and 15º, it is the middle section; and when the tilt sensor reading is less than -20º, it is the lower section.

[0100] According to the coal mine tunneling face operation regulations, the maximum air supply distance at the tunneling face is 2800m, and the compressed air volume is 560m when there is no loss. 3 / min, the air leakage of the air duct is known to be expressed by formula (1); the air leakage is calculated according to the maximum allowable air leakage rate at different air supply distances, and the minimum allowable air volume and wind speed at the end of the air compressor under different air duct distances are obtained. It is found that the wind speed at the end of the air compressor varies in the range of 5-12m / s. In order to explore the relationship between the minimum allowable air volume and wind speed at the end of the air compressor under different air duct distances, the wind speed range of 5-12m / s is divided into 7 working conditions at equal intervals, namely: 5-6m / s, 6-7m / s, 7-8m / s, 8-9m / s, 9-10m / s, 10-11m / s, 11-12m / s.

[0101] Using the cutting area and the wind speed range at the end of the compressed air duct as the basis for determining the working conditions, the three cutting areas (upper cutting, middle cutting, and lower cutting) and seven wind speed ranges are fully combined to form 21 working conditions, covering all operating scenarios of the mine's tunneling face under different cutting positions and different air supply distances. This provides a complete and unified working condition basis for subsequent numerical simulation experimental design, response surface analysis, and acquisition of the optimal airflow intelligent control scheme.

[0102] Table 2 Classification of Working Conditions at the Tunneling Face

[0103]

[0104] A gas-solid-liquid three-phase coupling calculation model was established at the tunnel face. 21 simulation test groups (15 cases in each group) were designed, totaling 315 numerical simulation cases. Numerical simulation was conducted to obtain data, and response surface analysis was performed using Design-Expert software to explore the optimal control scheme under various working conditions. The intelligent airflow control schemes under 21 working conditions are shown in the table below.

[0105] Table 3 Intelligent airflow control schemes under different working conditions at the tunnel face.

[0106]

[0107] The entire dust collection and air purification system is controlled by a PLC controller, and the surrounding environment is monitored. Wind speed sensor, dust sensor, laser rangefinder, and tilt sensor are connected to the PLC controller.

[0108] The PLC controller receives data from the wind speed sensor, dust sensor and tilt sensor and stores the data in the data storage module. The touch screen can display the data from each sensor.

[0109] The PLC controller processes the received dust sensor data and wind speed sensor data to obtain dust concentration prediction curves and wind speed prediction dimension curves, which are then displayed on a touch screen.

[0110] The PLC controller processes the data from the tilt sensor and the distance data transmitted by the laser rangefinder to obtain the cutting position of the tunneling and anchoring machine drum, and then sends the drum cutting position to the touch screen for display.

[0111] The PLC controller determines the operating conditions based on the cutting position, the distance between the dust control device and the cutting head as transmitted by the laser rangefinder, and the wind speed at the end of the air compressor. Based on the operating conditions, it determines the optimal intelligent control scheme and displays it on the touch screen.

[0112] Based on the "Coal Mine Safety Regulations" and numerical simulation analysis, the threshold values ​​for the dust concentration evaluation range of anemometers in typical coal mine tunneling faces were determined, as shown in Table 4 below.

[0113] Table 4 Evaluation Thresholds for Wind Speed ​​and Dust Concentration

[0114]

[0115] The PLC controller determines the optimal airflow control scheme based on the real-time judgment of the cutting area and the wind speed at the end of the air compressor. The PLC controller controls the angle deflection motor and the diameter change motor of the airflow dust control device 1. The angle deflection motor realizes the angle deflection of the exhaust port, and the diameter change motor realizes the adjustment of the exhaust port diameter. The intelligent control cabinet 5 supports manual control mode. It can realize permission switching and manual intervention by manually inputting parameters and quickly selecting schemes through the touch screen. All operation data is stored in the data storage module. Control records, scheme call history and over-limit alarm information can be retrieved and displayed visually on the historical data query interface of the touch screen, realizing the automated and intelligent closed-loop control of the airflow dust control device.

[0116] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural transformations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for dust control, collection, and air purification at a tunneling working face, characterized in that, The air purification method is based on a dust control and air purification system at the tunneling working face, and the air purification method includes: Step S1: Determine the optimal system layout; Step S2: Divide the tunneling face into sections; Step S3: Calculate the air leakage Q of the air duct based on the air supply distance and leakage rate of the air duct, and determine the air velocity at the end of the compressed air duct; Step S4: Based on the prediction model, make numerical predictions of wind speed and dust concentration at the next moment; Step S5: Divide the air velocity at the end of the air compressor into intervals, combine multiple cutting areas to form a multi-condition operation group. Step S6: Determine the optimal airflow control scheme based on the gas-solid-liquid three-phase coupling calculation model and the multi-condition operation group.

2. The method for dust control, collection, removal, and air purification at a tunneling working face according to claim 1, characterized in that, The cutting area is divided into upper cutting, middle cutting, and lower cutting based on the tilt angle of the boom, which is obtained in real time by the tilt angle sensor on the cutting boom of the integrated tunneling and anchoring machine. With the cutting wall horizontal as 0º, the inclination angle of the cutting arm at the upper part of the cutting is not less than 15º, the inclination angle of the cutting wall in the middle part of the cutting is in the range of -20º to 15º, and the inclination angle of the cutting arm at the lower part of the cutting is not greater than -20º.

3. A method for dust control, collection, removal, and air purification at a tunneling working face according to claim 1, characterized in that, The air leakage Q of the ventilation duct is expressed by the following formula: ； In the formula: m is the compressed air volume without loss, taken as... I represents the number of local ventilation units, which is set to 1; L represents the ventilation distance. This refers to the air leakage rate.

4. A method for dust control, collection, removal, and air purification at a tunneling working face according to claim 1, characterized in that, The prediction model is expressed by the following formula: ； ； In the formula: Let t be the predicted wind speed at time t+h based on historical monitoring data. Let t be the predicted dust concentration at time t+h based on historical monitoring data; This represents the smoothed horizontal term of the wind speed sequence at time t; This represents the smoothing level term of the dust concentration sequence at time t; This represents the trend update term for the wind speed sequence at time t; is the trend update term for the dust concentration sequence at time t; h is the prediction step size.

5. A method for dust control, collection, removal, and air purification at a tunneling working face according to claim 1, characterized in that, The dust control and collection air purification system includes: a flow dust control device (1), a two-stage dust collection device (2), an air curtain dust isolation device (3), a wet dust removal device (4), and a dust control and collection intelligent monitoring device. The flow dust control device (1) is installed at the air outlet of the telescopic duct (9). The two-stage dust collection device (2) is set along the length of the telescopic duct (9) and is parallel to the telescopic duct (9). The air curtain dust isolation device (3) has a U-shaped structure and is installed between the two-stage dust collection device (2) and the wet dust removal device (4). The wet dust removal device (4) is connected to the end of the exhaust duct by a converter (10). The dust control and collection intelligent monitoring device is installed on the right rear side of the tunneling and anchoring machine.

6. A method for dust control, collection, removal, and air purification at a tunneling working face according to claim 5, characterized in that, The airflow dust control device (1) includes an air outlet, a diameter adjustment unit and a direction adjustment unit. The air outlet is located at the front end of the air outlet of the telescopic air duct (9). The diameter adjustment unit is located on the outside of the air outlet to facilitate adjustment of the diameter of the air outlet. The direction adjustment unit is located on the lower side of the air outlet to facilitate adjustment of the direction of the air outlet.

7. A method for dust control, collection, removal, and air purification at a tunneling working face according to claim 5, characterized in that, The two-stage dust collection device (2) includes a primary dust collection port (2-1), a secondary dust collection port (2-2), and an exhaust duct (2-3). Both the primary dust collection port (2-1) and the secondary dust collection port (2-2) are rectangular structures. The primary dust collection port (2-1) is located at the top front end of the tunneling and anchoring machine, and the secondary dust collection port (2-2) is located at the rear of the tunneling and anchoring machine on the return air side. The primary dust collection port (2-1) and the secondary dust collection port (2-2) are connected by the exhaust duct (2-3) to achieve two-stage dust collection.

8. A method for dust control, collection, removal, and air purification at a tunneling working face according to claim 7, characterized in that, The air curtain dust removal device (3) has a U-shaped structure. Multiple exhaust ports are provided on the outer side of the air curtain dust removal device (3) along the circumferential direction to facilitate the outward spraying of airflow. The air curtain dust removal device (3) is located between the secondary dust collection port (2-2) and the wet dust removal device (4) to form an air door.

9. A method for dust control, collection, removal, and air purification at a tunneling working face according to claim 5, characterized in that, The wet dust removal device (4) is located above the belt conveyor and supported by the installation trolley (8). The wet dust removal device (4) is connected to the end of the exhaust duct (2-3) through the adapter (10).

10. A method for dust control, collection, removal, and air purification at a tunneling working face according to claim 5, characterized in that, The dust control and collection intelligent monitoring device includes a data acquisition unit and an intelligent control cabinet (5). The data acquisition unit is connected to the intelligent control cabinet (5). The intelligent control cabinet (5) includes a cabinet and a PLC controller. The PLC controller is installed inside the cabinet. The data acquisition unit includes a dust sensor (7), a wind speed sensor (6), and an inclination sensor. The inclination sensor is installed on the cutting wall of the tunneling and anchoring machine to facilitate real-time acquisition of the boom inclination angle. There are multiple dust sensors (7) and multiple wind speed sensors (6). The multiple dust sensors (7) detect the dust concentration at different locations and transmit the data to the PLC controller. The multiple wind speed sensors (6) detect the wind speed at different locations and transmit the data to the PLC controller.

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