船用惰性气体系统操作过程中静电灾害的预防

Prevention of Electrostatic Hazards in Shipboard Inert Gas Operations

油轮在惰性化的过程中,由于惰性气体发生器也会产生带电的烟尘,因而将在载油舱的上部空间积聚静电电荷。本文从理论上探讨了带电烟尘的扩散形式和烟气空间电场的分布情况,并且根据实船试验的情况确定,当惰性气体系统发生故障或有空气进入载油舱时,积聚于油舱顶部空间的静电电荷是否已经达到危险值,即是否具有引燃上部油气的能力。试验证明,尽管其静电电位已经限制到诱发刷形放电所需的电位值以下,但是,如果有孤立导体存在,则足以产生危险的火花放电。

During the inerting of a cargo tank, an electrostatic chargeaccumulates in the ullage space, owing to the carry-over of charged soot particlesfrom the inert gas generator. This paper theoretically discusses the diffusion formand the space electrostatic field distribution of the charged soot. And shipboardtrials are carried out to determine if the accumulated space potential attainsa value sufficient to generate electrostatic discharges capable of igniting flammable ullage gases when the inert gas system fails and air enters the cargotanks. It is discovered that though the potentials are limited to a value belowwhat is needed to generate brush coronas, they may be sufficient to producehazardous sparks from isolated conductors.