煤层钻孔孔口处除尘设计与试验研究

Design and experimental study of a dust removal device for coal seam drilling holes

为解决碎软煤层干式钻进施工过程中粉尘污染严重的问题,采用多级湿式除尘技术,并基于气水射流泵喷雾除尘原理,研发了一种新型煤层钻孔孔口除尘装置。通过数值模拟对除尘装置的结构参数进行了优化,并在中煤平朔小回沟煤矿开展了现场试验。结果表明,煤层钻孔孔口除尘装置二级除尘单元的最优喉嘴距为180 mm。煤层钻孔孔口除尘装置一级除尘单元的喷嘴角度选择95°最为合适,可实现集尘罩内全空间覆盖。供气压力0.6 MPa、供水压力0.3 MPa为二级除尘单元的最佳工作参数,该气水压配比下钻孔下风侧15 m内除尘效率可达到87.5%。在煤层钻孔孔口除尘装置采用二级湿式除尘并连接瓦斯抽采系统时,钻孔下风侧15 m内除尘效率达到了90.1%,此除尘模式可有效改善钻孔施工作业环境。

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.