Fatty acid separation is basically achieved in a combined stripper/distiller, where odours are removed at the same time: the fatty acids can be separated according to their different boiling points. Preheated fatty acid feed is made to flow through a series of reaction chambers.
Each reaction chamber is heated at the bottom, typically by superheated steam, which is injected into the feed in each chamber through a sparger. The low pressure imposed in the reaction chamber and the high temperature of the feed and the superheated steam flow all agitate and evaporate the fatty acids, in a form of distillation.

The vapours are led to a pipe header and condensed in a water-cooled condenser. The steam passes through, travelling on to the barometric condenser: the non-condensable gases are removed by a vacuum pump. The residue leaving the base of the last reaction chamber is cooled. In all these process steps measurements of pressure and temperature are crucial. One disadvantage of steam distillation of fatty acids is the formation of emulsions in the last stage of condensation, where a water spray is used. The calcium and magnesium salts typically present in the water spray react with the fatty acids forming soaps.
To recover the fatty acids, the soap is acidified and redistilled if desired.