Research And Application Of Regional Graded Dust Removal System In Fully Mechanized Mining Face

Dust control is an important problem in coal mine disaster management.A large amount of dust will be generated during the production process of the comprehensive excavation,which poses a huge threat to worker health and coal mine safety.However,it is impossible to effectively control the dust within the prescribed safety range cause the complex environment of the underground coal roadway,high dust amount,large ventilation volume and the small space of the fully mechanized mining face.In this paper,combined with the actual situation of the comprehensive excavation roadway,we find the current spray for the heading face usually turned back by the interference of airflow.The driver's seat is located on the high-concentration dust return channel and the work area behind the dust-containing air flow is polluted.Besides,the nozzle always blocked cause the poor water quality and the coal dust is difficult to wet.Based on the concept of grading dust removal and comprehensive treatment,a combination of theoretical analysis,numerical simulation,experimental testing and underground industrial test applications was used to propose a regional grading dust removal system.Which provide a new idea for the dust control of comprehensive excavation.The main results are as follows:A three-dimensional?-?turbulent mathematical model of single-phase air flow in the pressurized ventilation system was established.The numerical simulation of the air flow field in the fully mechanized face was carried out.The movement and distribution characteristics of the air flow in the roadway were analyzed.Results showed that:Due to the influence of roadheader,the dusty airflow in the heading area shows various distribution characteristics.The flow field near the front is complicated,the wind speed is fast and there are more eddies;there is a significant backflow phenomenon in the area above the roadheader;the wind speed in the area behind the roadheader suddenly decreases.Based on this,Aiming at the key locations of the turbulent flow area at the heading face,the position of the driver on the return channel and the rear area of roadheader,the regional dust removal system as"jet suppression in the heading area,dust separation and suction in the driver area,and filter dust removal in the transfer area"were proposed.The key dust removal system for the airborne dust in the comprehensive excavation face was designed accordingly.System equipment and materials composed of jet dust suppression device,dust separation air knife,pneumatic dust suction fan,scattering type dust removal equipment,filtering centralized control device and high-efficiency wet sticky dust agent.According to the characterization principle of jet spray,the structure of jet dust suppression equipment was preliminarily determined,the jet nozzle with adjustable angle was designed,and the atomization characteristic test system was constructed.The best operating condition of the jet dust suppression equipment was determined by the test:water pressure 2.5 MPa,nozzle angle 10?15°;using hydrodynamic basic equations to analyze the effect of structural parameters on the spraying effect,preliminary determination of the structure of the scattering dust removal device,fan-shaped atomizing nozzle is preferred,and the best operation of the scattering dust removal device is determined by experiments The operating conditions are:water pressure 3.5?4.5 MPa,wind pressure 0.4?0.6MPa;the operating parameters of the cyclone dust removal fan are tested based on the wind tunnel test system,and the results show that:under the condition of0.5 MPa wind pressure,the fan noise is 79.1 d B,the vibration is 0.198 mm,the suction radius is 1.2 m,and the treatment air volume is about 110 m³/min,which meets the design requirements.According to the selection principles of filter accuracy and size parameters,the size parameters of the filter element were calculated and analyzed,and the basic pore size of the filter screen was determined to be 75?m,and the filter area of the filter element was about 0.3 m².A new type of wet dust sticking agent was compounded in the experiment,and the best formula was determined as follows:the ratio of surfactant SAS-60 to AEO7 was1:4,the synergistic ion was Na SO₄and Mg Cl₂·6 H₂O,and the ratio of cellulose PAM to HPMC was 1:4.The viscosity of the wet dusting agent after compounding was 28 MPa·s.An industrial test was carried out on the comprehensive excavation roadway use the regional grading dust removal system of this paper.The results show that:after using the dust control system,the dust removal efficiency of the manned working area is more than 95%,which is more than 40%higher than traditional dust removal technology.The paper has 57 pictures,14 tables,and 93 references.