THEORETICAL DEVELOPMENT OF THE FEEDBACK CONTROL STRATEGY FOR BATCH CRYSTALLIZERS.

A feedback control strategy for batch crystallization processes that can be used to maintain a performance index at a specific nominal value has been developed. Two approaches, based on different starting approximations for the square of the difference between the perturbed and the nominal performance index, were considered and, the optimal control problems derived from these two approaches were shown to be equivalent. Then, a one-step iteration method was adopted to solve this transformed problem. Various numerical simulations, both open- and closed-loop, were carried out. The results show satisfactory and expected improvement for the operation of a batch crystallizer using the proposed control strategy.