煤矿井下瓦斯抽采PVC管道爆炸原因分析及预防

Analysis of Coal Mine Gas Explosion in Drainage Pipeline of PVC and Its Prevention

针对煤矿瓦斯抽采PVC管道静电引起的瓦斯爆炸事故,分析了PVC管道中静电产生和静电放电的原因,提出了预防PVC管道中静电灾害的技术。由于瓦斯在PVC抽放管路中流动时产生静电并在管道内壁产生静电积聚,所以在PVC管路和铁质流量计连接处,因两者导电能力不同,致使PVC管路产生静电,恰巧这时的瓦斯浓度达到爆炸范围,静电放电火花点燃瓦斯,造成瓦斯在管道内发生爆炸。为此,采用降低瓦斯在管道中的流速,抑制静电的产生;在输气管道的法兰接头、PVC管两端、阀门等连接处应用金属线跨接,防止静电放电;在气流输送系统的管道中央,顺其走向加设两端接地的金属线,以降低管内静电电位等方法,为矿井瓦斯抽采PVC管道防治静电灾害提供理论依据。

A case of gas explosion caused by electrostatic discharge in PVC pipeline for coal mine gas extraction was presented.The reasons of electrostatic generation in PVC pipeline and its discharge were analyzed.Prevention measures of electrostatic disaster in PVC pipelines were proposed.Cause of the accident is： when gas flows in PVC pipeline static electricity generates and accumulates on the inner wall of pipeline.At the connection of PVC pipeline with flow meter made of iron,discharge of static electricity occurred because of different conductivity.In the same time gas concentration reached explosive range,electrostatic discharge spark ignited the gas,resulting in explosion.Electrostatic hazard control methods are proposed： to reduce gas flow in pipeline,inhibit generation of static electricity;at pipeline flange joints,PVC pipe ends,valves and other connections use metal wire jumper to prevent electrostatic discharge;in the centre of pipeline transportation system,along its ends to set ground wires to reduce the electrostatic potential in pipeline.Results of the study provide a theoretical basis for prevention and control of static electricity disaster with use of gas drainage PVC pipelines.