ABSTRACT
Distillation is a process in which more volatile substances in a mixture are separated from less volatile substances. This separation can be carried out either by vaporising a liquid mixture or by condensing a vapour mixture. In the actual practice of distillation, liquid containing the volatile substances is heated to generate vapour which is separated from the mixture followed by condensation of the vapours as the distillate. The residue is rich with the less volatile components. Distillation may be carried out for both batch and continuous processes. Removal of low boiling components in small amounts by heating or by steam or by gas is called stripping. This is also similar to distillation and is used to remove dissolved gases from naphtha in a stabiliser column similar to a distillation column; to remove hydrogen sulfi de from a solvent (e.g., diethyl amine) used up in a hydrogen sulfi de absorber from a hydrocarbon gas mixture; and to remove undesired light fractions from straight run fractions for adjusting the fl ash point, etc.
