A de-asphalter is a unit in a crude oil refinery or bitumen upgrader that separates asphalt from crude oil or bitumen.

The de-asphalter unit is usually placed after the vacuum distillation tower. It is usually a solvent de-asphalter unit, SDA. The SDA separates the asphalt from the feedstock because light hydrocarbons will dissolve aliphatic compounds but not asphaltenes. The output from the de-asphalter unit is de-asphalted oil ("DAO") and asphalt.

DAO from propane de-asphalting has the highest quality but lowest yield, whereas using pentane may double or triple the yield from a heavy feed, but at the expense of contamination by metals and carbon residues that shorten the life of downstream cracking catalysts.[1] If the solvent is butane the unit will be referred to as a butane de-asphalter ("BDA") and if the solvent is propane, it will be called a propane de-asphalter ("PDA") unit.


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