Development of Structure Design for Divided Wall Column Using a Sloppy Distillation Arrangement

An efficient design method is proposed for the initial structure design of dividing wall column (DWC). Internal section of DWC is divided into four sections and matched to the sloppy arrangement with three conventional simple columns. The light and heavy key component mole-fractions are used as the design variable in each column. It is observed that the structure to give a superior energy efficiency in the shortcut sloppy case also brings a superior energy efficiency in the DWC while the optimal split rate of the DWC is different from that obtained from the sloppy case. Based on the extensive simulation study, a two step approach is proposed for the DWC design: the optimal DWC structure is firstly determined by applying the shortcut method to the equivalent sloppy configuration; the optimal split rate is then found under the resulting rigorous sloppy structure. The simulation study shows that the DWC designed by the proposed method gives a near-optimal structure.