Influence of Impurities on the Control of Heterogeneous Azeotropic Distillation Columns

Abstract

A concept is presented for the design of heterogeneous distillation columns under aspects of operability. The column behavior is analyzed using residue curve maps and a theoretical finite reflux/infinite length column. In particular, the influence of impurities on the operation of the column is discussed. Depending on the impurities, different control schemes with different designs of the process have to be used to guarantee robust performance. Here, robustness is not against modeling errors but against typical nonlinear phenomena such as the disappearance of the phase split in the decanter. The theoretical findings are illustrated by steady-state and dynamic simulations of an industrial column where a heavy-boiling organic substance is dewatered using methyl tert-butyl ether as a light entrainer.