Mixed‐logic dynamic optimization applied to batch distillation process design

An approach for the optimal configuration and sequencing of complex batch-distillation processes is presented. The proposed method is based on formulating a mixed-logic dynamic optimization problem in which a performance index is minimized subject to a disjunctive dynamic model and constraints. The disjunctive model comprises a given set of equipment modules, such as stacks of trays of different size or feed and product vessels, available for the distillation process under consideration along with logical relationships provided by the design context. The optimization based on this model may yield unconventional design and operational strategies, and thus improve the economic efficiency to a significant extent. The logic-based solution technique proposed in this work offers some favorable properties when compared to established mixed-integer dynamic optimization problem solution techniques reported in the literature. The design of a multistage batch-distillation process serves as an example to illustrate the proposed modeling and solution method.