Model predictive control of a binary distillation column


In the present study, a binary mixture, composed of ethanol/water, is considered. This mixture presents deviation from ideal behavior, which is taken into account using the Wilson model. The dynamic behavior of the distillation columns that separate this mixture is studied and transfer functions are obtained for a step in the reflux ratio, the reboil ratio and the feed composition. Then, the control of the columns using Model Predictive Control (MPC) is performed. The authors show that both distillate and bottom compositions are controlled while feed composition disturbances are rejected readily using MPC. Such calculations can be readily performed, using mathematical software available in most universities (Mathematica ® and Matlab ©), by students under the direction of a chemical engineering faculty in the context of a three-month senior term project.