Modelling and Control of Crystallizers

The modelling, measurement, and control problems associated with continuous, well-mixed crystallizers are discussed in this paper. The crystallizer model consists of an integro-partial differential equation, the population balance, coupled with a set of ode´s describing the overall reactor balances, such as solute concentration and temperature. Efficient methods for reducing this distributed model to a lumped model are formulated. A methodology for determining the stability of the population balance is developed and compared with the standard stability analyses of the approximate lumped models. Finally, the effect of simple feedback control on the crystallizer´s stability is discussed.