Separation process units are used to split a hydrocarbon stream into its components without changing molecule size and structure.

This is typically done by either distilling the feed to separate components based on their different boiling points, or by extracting one set of components from the rest based on their different solubilities in a solvent stream.

Some of the major separations processes are:

• Atmospheric distillation tower - Separates crude oil into its components based on their different boiling points

• Vacuum distillation tower - Separates atmospheric bottoms into its components based on their different boiling points

• Fractionator - separates the outputs from a conversion unit into its components based on their boiling points. Included as a part of many conversion units.

• Asphalt plant - Separates asphaltenes from Vac resid using a solvent.

• Base oil plant - A series of extraction processes to separate base oil from VGO or vac resid.

• BTX extraction - Extracts aromatics from reformate using a solvent

• Desalter - Extracts liquid salts from crude using water (as a solvent)