ON MINIMUM TIME OPTIMAL CONTROL OF BATCH CRYSTALLIZATION OF SUGAR

The problem of controlling the syrup feed rate and evaporation rate in a batch sugar crystallization process is solved as a continuous time optimal control problem. Constraints on nucleation boundary, flow viscosity, and pan-capacity are also incorporated. As opposed to transformation techniques by addition of slack variables used in the literature, these continuous state constraints are considered directly via an appropriate constraint transcription. This short communication reports on some new computed results based on a model by Ress [1]. Even though the present approach is more direct and simpler, the results obtained are consistent with that of a discrete model