Distillation and extraction techniques

The distillation of simple mixtures such as the binaries monochlorobenzene-ethylbenzene or benzene-toluene can be evaluated using the shortcut method, but that approach based on the Fenske equation quickly reaches its limits. More sophisticated methods, such as those developed by ProSim, are required to simulate separations of complex mixtures, in a high vacuum, with entrainer, with side stream extraction of liquid or vapor, and so on.

Usually, a continuous distillation process involves several interconnected columns to maximize the purity of the fractions and their returns.

This set-up is often complex because its definition is based on a scientific approach validated by laboratory and pilot scale testing before the industrial phase.

Liquid-liquid extraction is a procedure that enables the transfer of a component between two immiscible liquid phases. Depending on the volumes involved and the number of operations, it is easy to extract a product whose separation would have been difficult through distillation. This stage is generally used to supplement a more complex treatment that includes several distillation phases. This makes it possible to optimize the overall material yield while controlling energy expenditures.