Petroleum refining processes: Difference between revisions - Wikipedia

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==The crude oil distillation unit==

The crude oil distillation unit (CDU) is the first processing unit in virtually all petroleum refineries. The CDU distills the incoming crude oil into various fractions of different boiling ranges, each of which are then processed further in the other refinery processing units. The CDU is often referred to as the [[Atmospheric distillation of crude oil | ''atmospheric distillation unit'']] because it operates at slightly above atmospheric pressure.<ref name=Handwerk/><ref name=Leffler/><ref>{{cite book|author=Kister, Henry Z.|title=Distillation Design|edition=1st |publisher=McGraw-Hill|year=1992|isbn=978-0-07-034909-4}}</ref>

Below is a schematic flow diagram of a typical crude oil distillation unit. The incoming crude oil is preheated by exchanging heat with some of the hot, distilled fractions and other streams. It is then desalted to remove inorganic salts (primarily sodium chloride).