[visit our website]

an introduction
© Copyright 1997-2023 by M.T. Tham and R.C. Costello
Distillation is defined as: Boiling and condensing

a process in which a liquid or vapour mixture of two or more substances is separated into its component fractions of desired purity, by the application and removal of heat.

Distillation is based on the fact that the vapour of a boiling mixture will be richer in the components that have lower boiling points.

Therefore, when this vapour is cooled and condensed, the condensate will contain more volatile components. At the same time, the original mixture will contain more of the less volatile material.

Distillation columns are designed to achieve this separation efficiently.

Although many people have a fair idea what “distillation” means, the important aspects that seem to be missed from the manufacturing point of view are that:

arrored.gif (963 bytes) distillation is the most common separation technique
arrored.gif (963 bytes) it consumes enormous amounts of energy, both in terms of cooling and heating requirements
arrored.gif (963 bytes) it can contribute to more than 50% of plant operating costs
The best way to reduce operating costs of existing units, is to improve their efficiency and operation via process optimisation and control. To achieve this improvement, a thorough understanding of distillation principles and how distillation systems are designed is essential.

The purpose of this set of notes is to expose you to the terminology used in distillation practice and to give a very basic introduction to:

arrored.gif (963 bytes) types of columns
arrored.gif (963 bytes) basic distillation equipment and operation
arrored.gif (963 bytes) column internals
arrored.gif (963 bytes) reboilers
arrored.gif (963 bytes) distillation principles
arrored.gif (963 bytes) vapour liquid equilibria
arrored.gif (963 bytes) distillation column design and
arrored.gif (963 bytes) the factors that affect distillation column operation