This paper presents simulation and analysis of multiple steady states (MSS) in dividing wall column (DWC). First steady state simulation of benzene-toluene-xylene (BTX) separation in DWC is run to obtain its four different solutions using Aspen Plus software, and then detailed comparisons and analysis of these solutions are carried out. From simulation results, it can be concluded that MSS inevitably exists in DWC, which is important for its design, operation and control but has not been declared in open literature up to now. In addition, obvious grouping feature is found among the four solutions of BTX DWC case, and light component benzene and heavy component xylene have, respectively, two different recoveries at the top of the side column among the four solutions. The grouping feature is interesting and important for DWC, which may be explained by the existence of impurities in side product stream and their different flow paths from the feed to the side product stream, that is, above or under the dividing wall. Figure 1. Schematic representation of (a) dividing wall column and (b) Petlyuk column.
E. WANGAsia-Pacific Journal of Chemical Engineering 76