R. Chopp et R. Pape, THE POTENTIAL OF SUFFICIENT STATIC ELECTRICITY FOR IGNITION DURING TANKER WASHING, Process safety progress, 16(1), 1997, pp. 25-31
Waste-derived fuel is an environmentally friendly method for destroyin
g waste and recovering the energy value it contains. The fuel is chara
cterized as a mixture of various solvents with a flashpoint in the fla
mmable range. In addition to these solvents, the waste fuel contains s
olid material. During the transfer of this material to storage tanks,
some of the solid material is left behind in the tankers and rail cars
. The ideal solution to remove this solid material is to wash the tank
vehicle with the same waste fuel. With the waste fuel being in the fl
ammable range, there is a concern about the washing operation causing
ignition due to static electricity. Scaled experiments were conducted
to assess the potential for static electricity to cause ignition. Alth
ough several ignition mechanisms were assessed, this paper is concerne
d with the charged mist caused by the high velocity solvent jet imping
ing on the tank wall. Isopropyl alcohol, mixed xylenes, and mineral sp
irits were evaluated. An aerosol electrometer was used to measure char
ge per unit volume of mist sampled. Discharge generation was assessed
using an analytical model which estimates electric field corresponding
to measured charge density for various configurations.