Design and Control of an Extractive Distillation System for Benzene/Acetonitrile Separation Using Dimethyl Sulfoxide as an Entrainer

A method for benzene/acetonitrile separation using extractive distillation is presented, and dimethyl sulfoxide (DMSO) is selected as the entrainer. Steady state and dynamic simulations for this process are implemented by commercial simulators (Aspen Plus and Aspen Dynamics). On the basis of global economic optimization, a design with optimized operation conditions for this process is developed. Two single temperature control structures with fixed reflux ratio or fixed reflux-to-feed ratio and a dual-end temperature control structure for entrainer recovery column are presented to evaluate the dynamic performance with feed flow rate and feed composition disturbances, and the last structure is quite effective.