Separation by Forming a Ternary Azeotrope

In this process, the entrainer E, added to the close-boiling or azeotrope-forming binary AB, forms a low-boiling ternary azeotrope, ABE. The ternary azeotrope boils at a temperature lower than A or B or their binary azeotrope, if it exists. The ABE azeotrope is removed in the column overhead, while pure component A or B is recovered in the bottoms. 

The amount of entrainer is calculated by material balance. Using similar nomenclature for rates and compositions as in the previous section, the following equations are written for total and component material balances  

The entrainer-to-feed ratio is calculated by combining the last two equations  

These derivations are based on the assumption of total azeotrope formation and 

A schematic of a flowsheet utilizing the ternary azeotrope phenomenon to sepa- 

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