Atmospheric distillation is a relatively simple process separating lower boiling point liquids at ambient pressure. Used oil is heated (A) and charged to a distillation tower (B). Lower boiling point hydrocarbons present in the used oil (eg gases, petrol and solvents) and water are collected at the top of the tower (B). Some of these hydrocarbons can be condensed and collected for use as a fuel in the refining process.