Design and experimental study of a dust removal device for coal seam drilling holes
To address the significant challenges posed by dust pollution during dry drilling in soft crushed coal seams,this study centers on the dry drilling process at China National Coal Group Corp Pingshuo Xiaohuigou Coal Mine.Drawing inspiration from this process,a novel dust removal device for coal seam boreholes is conceptualized.This innovative design incorporates multi-stage wet dust removal technology and air-water jet spray dedusting principles to combat dust emissions effectively.In pursuit of achieving optimal dust removal efficiency,this study conducted numerical simulation optimization of the structural parameters of the equipment.Additionally,experiments were conducted at the China National Coal Group Corp Pingshuo Xiaohuigou Coal Mine to explore how efficiency is influenced by different nozzle angles,various combinations of air pressure and water pressure,and to compare different dust removal modes.The results indicate that the secondary dust removal unit's optimal throat distance is 180 mm,leading to maximum efficiency for the spray dust removal device.The primary dust removal unit has a nozzle angle of 95°,ensuring full coverage within the dust collection hood.The secondary dust removal unit operates optimally at 0.6 MPa gas and 0.3 MPa water supply pressure.As a result,the dust removal efficiency within 15 m downwind of the drilling hole can reach 87.8％.When a secondary-stage wet dust removal device was incorporated into the coal seam hole dedusting system,connecting to the gas extraction system,the dust removal efficiency within 15m downwind of the boreholes reached 90.1％.This dedusting method effectively reduced secondary dust emissions and enhanced the negative pressure suction efficacy,thereby notably improving the drilling construction environment.The research findings hold significant application and dissemination value,offering theoretical insights for designing and utilizing dust removal devices in coal seam boreholes.
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