Summary: Control Study of Ethyl tert-Butyl Ether Reactive Distillation
Muhammad A. Al-Arfaj
Department of Chemical Engineering, King Fahd University of Petroleum and Minerals,
Dhahran, Saudi Arabia
William L. Luyben*
Department of Chemical Engineering, Lehigh University, Bethlehem, Pennsylvania 18015
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.
The use of reactive distillation has grown in recent
years because it results in less expensive and more
efficient processes for some chemical systems. There is
increasing interest in the use of ethyl tert-butyl ether