Azeotropic distillation

Phase diagram (left) and process flow diagram (right) of an apparatus for the azeotropic distillation with "material separation agent". In this case the phase diagram includes a zone where components are not miscible, so following the condensation of the azeotrope, it is possible to separate the liquid components through decantation.

In chemistry, azeotropic distillation[1] is any of a range of techniques used to break an azeotrope in distillation. In chemical engineering, azeotropic distillation usually refers to the specific technique of adding another component to generate a new, lower-boiling azeotrope that is heterogeneous (e.g. producing two, immiscible liquid phases), such as the example below with the addition of benzene to water and ethanol.

Common Equipment used in Azeotropic Distillation

This practice of adding an entrainer which forms a separate phase is a specific sub-set of (industrial) azeotropic distillation methods, or combination thereof. In some senses, adding an entrainer is similar to extractive distillation.

  1. ^ Kister, Henry Z. (1992). Distillation Design (1st ed.). McGraw-Hill. ISBN 0-07-034909-6.