可燃性气体对PE粉体静电放电点火的影响

Effect of combustible gas on ignition of PE dust electrostatics discharge

运用标准粉尘爆炸测试装置Hartmann管分别测试了聚乙烯(PE)粗料和经过筛分的PE粉体的最小点火能量,比较了PE粉体和可燃性气体共存时(即杂混合物)的最小点火能量与不同形式的静电放电能量。当PE粉体粒径小于2 mm时,随着粒径的增大,可燃性气体对杂混合物最小点火能量的影响也越大,但可燃性气体对PE粉体静电点火的影响变小。当可燃性气体浓度低于10%爆炸下限时,对未经过筛分的原始粉体,各种形式的静电均无法将其点燃;对粒径小于0.5 mm的PE粉体,可以排除电晕放电、刷形放电和堆表面放电作为点火源的可能性;对粒径小于75μm的PE粉体,堆表面放电、火花放电和传播型刷形放电均是可能的点火源。

The minimum ignition energies （MIE） of the coarse polyethylene （PE） granule and screened polyethylene dust were tested with a standard dust explosion testing equipment of Hartmann tube. The MIE of PE dust coexisted with the combustible gas was compared with the electrostatic discharge energy in various forms. In case the particle size of PE dust was less than 2 mm, the effects of the combustible gas on MIE of the PE dust remarkably increased with the particle size; however, the impact of the combustible gas on ignition of electrostatics discharge of PE dust declined. When the combustible gas concentration was below 10% of its lower explosion limit, electrostatic discharge in all forms was unable to ignite the unscreened original PE granule. For the PE dust with diameter below 0.5 mm, the possibilities of ignition caused by corona discharge, brush discharge and cone discharge could be excluded even in the presence of combustible gas. For PE dust with diameter below 75 μm, cone discharge, spark discharge and propagating brush discharge were considered as the possible ignition sources.