Patent ID: 7208079

Claim:
A process for the treatment of waste oil, comprising the steps of: a) supplying a stream of the waste oil to a dehydrator to dehydrate said waste oil and obtain a stream of dehydrated waste oil; b) supplying said stream of dehydrated waste oil to a fractionated distillation column having a lower tray, an upper tray and a middle tray therebetween, wherein said lower tray is operated a temperature of 370 to 390° C. under a sub-atmospheric pressure of 50 to 100 mmHg thereby substantially completely retaining in a bottom product any heavy metal contaminants comprised in the waste oil, said middle tray is operated at a temperature of 265 to 280° C. under a sub-atmospheric pressure of 35 to 45 mmHg and said upper tray is operated at a temperature of 100 to 110° C. under a sub-atmospheric pressure of 30 to 40 mmHg; c) withdrawing from said distillation column the bottom product comprising a bituminous material and, the heavy metal contaminants; d) withdrawing a first side stream from said distillation column between said first and second tray, said first side stream comprising a heavy oil having a viscosity of 130 to 180 cSt at 40° C.; e) withdrawing a second side stream from said distillation column between said second and third trays, said second side stream comprising a light base oil having a viscosity of 38 to 43 cSt at 40° C.; f) withdrawing a third side stream from said distillation column above said third tray, said third side stream comprising diesel having a viscosity of 4 to 7 cSt at 40° C.; g) withdrawing from said distillation column an overhead product comprising naphtha; and h) recovering said bituminous material, said heavy oil, said light base oil, said diesel and said naphtha.