Optimization of Batch Heteroazeotropic Distillation Operational Strategies with Entrainer Recycle

The batch heteroazeotropic distillation (BHAD) separation of a minimum boiling azeotropic mixture (isopropyl alcohol(A) - water(B)) with toluene as entrainer(E) is simulated and optimized with GA. The production cycle consists of processing three consecutive batches. Both BHAD operational modes (sequential (Mode I) and simultaneous (Mode II) distillation + decantation) are studied. The E-rich phase and (eventually) the off-cut can be recycled to the next batch to reduce the loss of both isopropyl alcohol and the entrainer. The optimization variables are the amount of E added to the charge and the reflux ratios of the steps. The effect of the recycling is discussed and the optimization results are compared with those of the non-optimized processes.