Finding batch extractive distillation product sequence from thermodynamic insights

Feasibility analysis of the extractive distillation processes mainly considers the general features of the residue curve map. However, the influence of unidistribution and univolatility lines has not been considered to its full extend. In this paper, we demonstrate the essential role of both thermodynamics properties along with the residue curve map for determining the product sequence and the column configuration without any calculation. The analysis is performed through the separation of binary mixtures having a low relative volatility by using heavy and light entrainer. Thermodynamic insight predictions are corroborated by the computing of the map of extractive composition profiles for several operating conditions and using a simplified mass balance. This behaviour is further corroborated by rigorous simulation using ProSim Batch. These results demonstrated the obligatory incorporation of the univolatility lines in the synthesis of the extractive distillation even for the simplest cases