Optimization of the Process of Batch Distillation of Binary Mixtures

The method of dynamic optimization, known as maximum principle of Pontryagin, is presented. It is applied to the process of batch rectification of binary mixtures, with aim of solving the problem of minimum time (for given distillate quantity of specified composition) or maximum distillate quantity of specified composition (for given batch time). The optimum profiles of reflux ratio are found for seven different separation tasks, based on semi-rigorous model without holdups. The results obtained for distillate quantity are compared to respective results obtained with constant reflux ratio and constant distillate composition working policies, and also with the results of other authors. The solution algorithms for all the three working policies are given. Computer implementation of the algorithms is performed in programming language FORTRAN.