The reduction of extractive agent in extractive distillation and auto-extractive distillation

Methanol–acetone, methanol–methyl acetate and methanol–chloroform were used as binary systems in extractive distillation and water–methanol–acetone, water–methanol–methyl acetate and water–methanol–chloroform were used as ternary systems in auto-extractive distillation, to study the possibility of reducing the specific consumption of extractive agent (q) and therefore, to reduce energy consumption of the separation process. Water was used in both binary and ternary systems as the extractive agent. Increasing the distance between the mixture feed and extractive agent feed along the separation column led to a 35–40% reduction in the specific consumption of extractive agent, while splitting the extractive agent feed into two branches on the column led to a further reduction of 25–30%. Computer simulation with HYSYS supported the conclusions for the binary methanol–acetone system.