Study On Dust-isolation Technique With Air Curtain At Fully-Mechanized Work Face For Thin Coal Seam

With the increasing of coal demand in China and the extension of production life in mining area, the high-class coal resources decreases rapidly. As its unique mining conditions and inevitable economic advantages, the thin seam mining obtained more and more concerns. And along with the improvement of mechanization degree in coal mines, dust problem in coal face are prominent gradually. Meanwhile, people’s labor protection awareness growing as the social progress and economic development. Therefore, the research and development of effective dust technology is imperative in fully mechanized working face.Air curtain technology(ACT) has been used in coal mine to control dust, but most of the research aimed at thick and medium-thickness seam, the related parameter design of ACT in fully mechanized working face of thin seam were very scanty and further study was necessary. Therefore, this paper choose the 22410# fully mechanized working face of thin seam, Jizhong Energy Resources Co., Ltd., as research object, though theoretical analysis, numerical simulation and laboratory tests, study the application of ACT in thin seam and the conclusions are obtained as fellows:(1) By theoretical calculation, the respirable dust movement and distribution discipline are acquired and its status mainly affected by the face aircurrent and lateral disturbance current in the fully mechanized working face of thin seam. Meanwhile, simplification basis are determined about the dust migration dynamic of numerical simulation.(2) Though Fluent numerical simulation, the dust distribution discipline and its main impact factor are acquired in the fully mechanized working face of thin seam. The numerical calculation results show that: dust diffusion range in fully mechanized working face increase with the improvement of the lateral disturbance current, decreasing with the drop of the wind velocity, so improving the inlet velocity suitably can achieve the purpose of dust exhausting.(3) With shearer depth increases, the yield of shearer decreases and the distance between shearer driver and coal wall extends, the dust concentration at shearer driver decreases. If conditions permits, the fully mechanized working face of thin seam should employ depth-web shearer.(4) Through theoretical calculations, determine the relationship between the air curtain entraining air volume and outlet width or outlet velocity, then optimize the parameter configuration of ACT by numerical simulation. The simulation results indicate that: under simulated conditions, the optimum length of the air curtain is 4.3m, outlet width is 20 mm, outlet velocity equals 6m/s, and the installation angle should be controlled within the range of 5°~10°, the maximum isolation dust efficiency of air curtain reaches to 94.30%~96.72%. The air curtain has significant control effect for respirable dust, indicating that ACT has its application prospects and research value for dust control in thin seam.(5) Through laboratory test, the dust particle size distribution are measured, under the experimental conditions, the dust distribution discipline and optimal parameter configuration of ACT are determined in thin seam. The results show that: a reasonable dust isolation parameter allows the air curtain reaching the favorable dust isolation effect for the full dust, which average particle size equal 87.852μm, and dust isolation efficiency are 74.7%.