Batch distillation is still widely used in numerous chemical plants that make multipleproducts at a relatively small scale. As in continuous distillation, various combinatorialsequences of batch separations can be derived. Each of these sequences can beoptimized using commercial simulator and compared with the other sequences. Theobjective function in optimization of batch distillation is usually the cycle time thatneeds to be minimized. It corresponds to the minimum energy of separation incontinuous distillation, because batch distillation columns operate usually at maximumboilup. Therefore, the shorter the cycle time, the lower the energy of separation.Optimization procedure has to take into account sizes of existing tanks and otheravailable equipment, which may lead sometimes to a classical scheduling problem.An example of selecting the optimum batch distillation sequence will be presented. Thecomponents in the feed may be lumped into five groups, ordered according to theirvolatilities:1. Lights (L), 2. Product A, 3. Intermediates (I) , 4. Product B, 5. Heavies (H).Combining optimization with batch column model available in commercial simulatorprovides a useful tool for developing optimum batch distillation recipes.
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