Crude Oil Distillation Unit (CDU) This video explains the Crude Oil Distillation Unit (CDU), the first step in petroleum refining. It shows how crude oil is heated and separated into different fractions inside an atmospheric distillation column based on boiling points. Learn how products like refinery gas, gasoline, naphtha, kerosene, diesel, heavy oils, and bitumen are obtained, and why further processes such as cracking and reforming are required. Ideal for engineering and vocational students.