FEASIBILITY OF EXTRACTIVE DISTILLATION IN A BATCH RECTIFIER

A simple method was developed to study the feasibility of extractive d istillation in a batch rectifier. By calculating feasible profiles of different column sections and figuring them in the triangular diagram, the feasibility and limiting values of the most important operational parameters (number of stages, flow rate of entrainer, and reflux rati o) were determined for different steps of the batch extractive distill ation. The unusual behavior of extractive distillation was also invest igated for this process. An infeasible region can be assigned to the g iven values of parameters; if the still composition is located within this region, the specified separation cannot be attained By locating t his infeasible region, maximum recoveries attainable in a batch rectif ier and in a middle vessel column were compared. The results obtained by this method were verified by pilot-plant experiments for the mixtur e acetone-methanol + water.