An Extractive distillation process is used to separate binary mixtures such as azeotropic mixtures which are difficult to separate using conventional distillation process.The process draws off a specific component to the bottom of column with the extractant which has a relatively higher boiling point than the products and is compatible with a specific component.In this case,only sensible heat is consumed because the extractant is not drawn off from the top of column.Therefore,the process has an advantage in terms of saving energy compared with simple distillation processes.This extractive distillation process requires two columns (washing column and extractant recovery column).A Divided Wall Column contains both product separating and extractant recovering sections separated by a wall in a specially designed column.Furthermore,heat integration has possibility which resulted in energy saving.