Atmospheric distillation of hydrocarbons-containing liquid streams

A method of distilling a crude oil and a contaminated liquid stream containing light hydrocarbons in an atmospheric distillation column comprising a stripping section, a rectification section and an inlet section located between the stripping and the rectification section, which method comprises the steps of

• (a) heating the crude oil at atmospheric pressure to a predetermined temperature in a furnace, and introducing the heated crude oil into the inlet section of the atmospheric distillation column;
• (b) removing from the bottom of the atmospheric distillation column a residue, removing from the top of the column an overhead, and removing from the rectification section of the column at least one side stream;
• (c) cooling at least part of at least one of the side streams and introducing the cooled side stream(s) into the rectification section at a level above the level of removal, and partly condensing the overhead and introducing the condensed fraction of the overhead into the upper end of the atmospheric distillation column;
• (d) supplying the contaminated liquid stream containing light hydrocarbons to the inlet of a membrane unit provided with a membrane, and removing from the permeate side a permeate and from the retentate side a retentate;
• and
• (e) introducing the permeate into the rectification section and adding the retentate to the crude oil upstream of the furnace.