Control Study of Ethyl <i>tert</i>-Butyl Ether Reactive Distillation

Abstract

Control structures for ethyl tert -butyl ether (ETBE) reactive distillation columns are studied. Two process configurations are explored: a design with two fresh reactant feed streams and a design with a single mixed reactant feed. An optimum design for the double-feed case is presented. A design given in the literature is used for the single-feed case. Several control structures are investigated, and their effectiveness in the ETBE case is compared with that in previously studied chemical systems. Results show that the double-feed system requires internal composition control to balance the stoichiometry, along with temperature control to maintain product purity. The single-feed case, which operates with an excess of ethanol, is effectively controlled with only a temperature controller provided disturbances are not too large.