低导电性油品及液氢流体在储罐内的静电电位计算

Calculation of electrostatic potential of low conductivity hydrocarbon products and liquid hydrogen in tanks

研究了低导电性油品及低温液氢流体带静电后存储于圆柱形储罐内时形成电位的原理和分布规律。利用贝塞尔函数求解静电场泊松方程和拉普拉斯方程,得到了储罐内液体和气体部分电位值分布的表达式,绘制了电位分布曲线。分析了储罐结构参数、流体性质以及电荷密度等作用参数对于电位大小的影响,并得到电位值随这些参数的变化规律。

Static electricity can be generated at the interface between a fluid and a solid surface. Hydrocarbon products as well as liquid hydrogen in chemical and energy industry are of low conductivity, inflammable and explosive,which enables the static charge easily accumulated,resulting in high electric potentials and electric fields during its transportation and storage.To avoid safety hazard due to sparks of sufficient energy for an explosion to occur inside a tank,this paper studied the formation and distribution of electrical potential of some typical hydrocarbon products and liquid hydrogen in cylindrical vessels. Poisson equation and Laplace equation were solved by using Bessel function to get the potential value distribution of liquid and gas in the tanks.The impact parameters such as tank structure,fluid properties and charge density to the potential were analyzed.The potential variation behavior against the above parameters was obtained.It was found that the maximum static potential appears at about 72% of the liquid level/height from the bottom instead of the liquid-gas interface.The calculations also showed that the potential reaches its crest value for each fluid studied when the filling rate is 65%—75% of the full capacity.Some suggestions were given for design of low conductivity fluid tanks to avoid high electric potential safety hazard.