Multi-Component Distillation

Table of Contents

What is Multi-Component Distillation?

Multi-component distillation is used for the separation of a liquid mixture containing more than two different components. Multi-component distillation units are able to separate each of the components into relatively pure streams through a series of distillation columns. For example, a liquid stream containing three separate components would first undergo distillation by entering a column that vaporizes the most volatile compound and leaves the two remaining less volatile components in the bottoms liquid stream. The most volatile component could be extracted there by condensing the vapour from the first distillation column. The remaining mixture of two less volatile components would then pass into a new distillation column that would be heated to a higher temperature to enable the most volatile component in the remaining binary mixture to vaporize. The more volatile component would then be condensed and collected through a top products feed while the least volatile component is extracted through a bottoms liquid feed. This process enables the separation of more than two components in a liquid mixture by feeding the liquid feed through a series of multi-stage distillation columns [1]. 

How to Build a Multi-Component Distillation Unit

A multi-component distillation unit contains similar features to a binary component distillation unit. A multi-component distillation unit would need to contain more than one multi-stage distillation column to enable the separation of however many components there are in the liquid feed of interest. Each column would need a heater or reboiler that can heat each feed to a different temperature as each subsequent column would need a higher temperature to facilitate the distillation of the remaining feed as the less volatile components that stay in the liquid feed mixture will need a higher temperature to boil. Distillation columns will also typically use packed material to improve liquid-vapour contact and allow for a higher degree of purity in the final separated streams [3]. 

Advantages and Disadvantages of Multi-Component Distillation

Industry Applications

Multi-component distillation can be used frequently in the petroleum industry for liquid mixtures with multiple hydrocarbons. For example, a mixture of hydrocarbons that contains propane, butane, pentane, and hexane could be separated into its individual components through a series of distillation columns and condensers to take advantages of different volatilities. These distillation columns would each need to operate at the given temperature required to boil a distinct liquid component.

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