Modelling the electrostatic ignition hazards associated with the
cleaning of tanks containing flammable atmospheres
Journal of Loss Prevention in the Process Industries, 14 (2):
129--133 (March 2001)DOI: http://dx.doi.org/10.1016/S0950-4230(00)00029-2
Abstract
High-velocity jets of water or solvent are commonly used to clean
tanks which have contained flammable liquids. This process creates
a charged mist which can lead to the generation of an electrostatic
spark or brush charge that may ignite any flammable atmosphere present.
Operators need to know the risk associated with their processes and
modelling can help assess it. Numerical techniques are available
to solve electrostatic problems for general tank geometries but tend
to be expensive and difficult to use. This paper shows how Green's
function can be used to solve Poisson's equation for a vessel of
cylindrical geometry and finite length containing charged mist. For
uniform space charge density, an analytical solution can readily
be implemented using cheaper proprietary software. An example from
an industrial investigation is described in which the internal walls
of a cylindrical vessel were washed with solvent jets.