Analytical Design and Operation of Systems with Crystallization, Filtration, and Recycling

Previously, Ward et al. [Ward, J. D.; Doherty, M. F.; Yu, C. C. Plantwide Operation and Control of Processes with Crystallization. AIChE J. 2007, 53, 2885-2896] published a novel shortcut method for predicting how process operation will be affected by the choice of control structure for a plant with reaction, crystallization, and recycling. The analysis assumed the presence of a continuous filter but did not model its operation. In this article, we introduce an analogous dimensionless model for a continuous rotary drum filter and show that a similar methodology can be used to predict the behavior of a combined crystallizer and filter, and a reactor, crystallizer, filter, and recycle circuit. We show the effect of the crystallizer operating policy on the operation of the filter and show that the overall operation of the combined plant can be predicted for a given choice of controlled variables. This facilitates the screening of control structures by rapid elimination of control structures that are likely to lead to infeasible or uneconomic modes of operation.