Simulation study of divided wall distillation column

Abstract

These days the center is on energy-saving advances. Several techniques have been proposed inorder to improve the efficiency of distillation process; dividing-wall column is one of thesetechniques. Conventionally, distillation columns are connected in series to separatemulti-component mixtures into more than two product streams with high purity prerequisites. However, in the dividing-wall column, middle section is divided into two sections by inserting avertical wall in the vessel at an appropriate position. Feed is introduced into the pre-fractionatorside of the wall. A side stream is removed from the main column. Therefore, a single dividingwall column can separate a ternary mixture into three pure product streams. The side stream ismostly the intermediate boiling component of the ternary mixture.In the present study a mathematical model of the dividing wall column has been developed,which incorporates the material balance, energy balance, and equilibrium relationships. This model was simulated by taking four columns in an equivalent divided wall distillation column sequence using aspen Plus. This particular design was used to study the separation of three ternary mixtures, Benzene-Toluene-P-Xylene, Benzene-Toluene-O-Xylene and Methanol- Water-Glycerol. The effects of several parameters suchas reflux ratio, number of trays, feed composition, and splitting ratio have been discussed to findthe optimum operating conditions.