Optimization of fed-batch reactors by the Luus-Jaakola optimization procedure

The presence of numerous local optima makes optimization of fed-batch react ors a challenging problem. In addition, the low sensitivity of the performa nce index on the control policy makes it very difficult to determine the op timal control policy accurately. As an alternative to iterative dynamic pro gramming, we consider the application of the direct search optimization pro cedure of Luus and Jaakola (AIChE J. 1973, 19, 760-766) with the recent ref inements involving the use of a quadratic penalty function with a shifting term to handle equality constraints. In using the optimization procedure in multipass fashion, we use the extent of variation of the variables in a pa ss to provide the region size for the beginning of the subsequent pass. In establishing the optimal control policies for three fed-batch reactor model s, we show that this approach provides a good way of solving such optimizat ion problems.