A novel method for determining the optimal operating points of reactive distillation processes

Abstract

Reactive distillation (RD) allows reaction and separation to take place simultaneously in the same unit, thus giving major benefits especially to equilibrium limited reactions. Although the application of RD in chemical industries is attractive, it is considerably challenging. Unlike classic distillation, the optimal configuration of RD from an economical perspective is hardly identified quickly. Usually, any specific reaction system may need extensive studies and rigorous simulations to develop a RD model. This study aims to determine the optimal operating points of a RD application in a quick and reliable way. A novel method is employed for a clear visualization of the RD applicability area (i.e. a plot of reflux ratio vs number of stages). Using this method, an economic analysis can be performed resulting in essential insights into the optimal configurations. The production of amyl acetate by esterification of amyl alcohol and acetic acid is selected as case study, since this reaction sufficiently represents non-ideal behaviours in real systems. The outcome of the analysis reveals that the boundary line of its RD applicability graph consists of the optimal points of RD configurations which generate the lowest total annual cost in the RD operation. Furthermore, it is observed that the additional cost for the reactive section (relative to a separation section) is marginal, which means that the rules of thumb for the optimal configurations in classic distillation could also be applied.