Application of the method of characteristics to crystallizer simulation and comparison with finite difference for controller performance evaluation

Finite difference methods are widely used to simulate crystallization proce sses, although they suffer from numerical dispersion. The method of charact eristics can tackle this problem, but the traditional algorithm cannot simu late crystallization processes, if the growth rate depends on crystal size, or if discrete control actions are taken. This paper shows how the method of characteristics can be applied to simulate such processes. Furthermore, the impact of numerical dispersion is discussed by comparing simulation res ults obtained from these two algorithms. It is revealed that the optimal ga ins and the responses obtained with a finite difference method are clearly different from those with the method of characteristics. (C) 2000 IFAC. Pub lished by Elsevier Science Ltd. All rights reserved.