Set Trimming approach for the globally optimal design of sieve trays in separation columns

In this article, we use Set Trimming to obtain the globally optimal design of distillation column trays, that is, the column diameter and the geometrical design of the trays (weir, downcomer, etc.) that minimize mass or cost. We assume that the operating conditions (vapor and liquid flow rates, compositions, temperatures) are given. The design task is, to this day, presented in textbooks as a trial and verification procedure. We show that Set Trimming guarantees global optimality and is amenable to exploring alternative global optima. Compared with the employment of a mixed‐integer nonlinear programming (MINLP) approach using commercial global optimizers, we show that Set Trimming is a more robust option with competitive computational times for individual design problems. It also exhibits a significant reduction in computational effort when alternative optimal solutions are sought.