Properties Of Solvent Used For Extractive Distillation

The solvent to be used is selected on the basis of :

1) Selectivity

2) Volatility

3) Ease of separation from the top and bottom products

4) Cost of separation

The selectivity is most easily assessed be determining the effect on the relative volatility of the two key components of addition of the solvent. The volatile the solvent, the greater the percentage of solvent in the vapor, and the poorer the separation for a given heat consumption in the boiler.