Effects of Thermal Feed Quality on the Performance of a Divided Wall Distillation Column

The present work deals with the effect of thermal feed quality on the performance of a divided wall distillation column (DWC). The thermal condition of the feed alters the pressure profile across the two sides of the dividing wall, thereby affecting not only the mass transfer characteristics but also the hydrodynamics of a DWC. It was observed that the natural (feasible) vapor split ratio does not depend on the liquid split ratio and the reflux flow rate when the feed is saturated liquid or sub-cooled liquid (q ≥ 1). However, for q < 1, that is, for two phase (vapor-liquid), saturated vapor, or superheated vapor feed, the liquid split ratio and the reflux flow rate have profound effect on the feasible vapor split ratio, and the pressure profiles are altered significantly. For the stable operation of a DWC, the feed should be either saturated liquid or sub-cooled liquid or the feed quality may be manipulated to adjust the vapor split ratio.