ETBE SYNTHESIS VIA REACTIVE DISTILLATION .1. STEADY-STATE SIMULATION AND DESIGN ASPECTS

Ethyl tert-butyl ether (ETBE) is an alternative gasoline oxygenate tha t combines the blending properties of methyl tert-butyl ether (MTBE) a nd the renewability of ethanol. Technologically, the best means of syn thesis utilizes reactive (or catalytic) distillation to maximize hydro carbon conversion and energy efficiency while simultaneously producing a high-purity ether product. Mathematical models of reactive distilla tion are based on the conventional distillation process with supplemen tary equations added to model the reactions present. Ether-alkene-alco hol systems are highly nonideal in the liquid phase so that careful se lection of physical property routines is required to ensure satisfacto ry simulation results. Column simulations performed here using both Pr o/II and SpeedUp show excellent agreement with previously published ex perimental data for a MTBE system and also agree well with each other for both MTBE and ETBE systems. A homotopy analysis was performed on t he tuned simulation models to determine the effects of key design and operating variables on column performance and, subsequently, to develo p a design method for reactive distillation columns. Some unusual beha vior was identified in ETBE reactive distillation columns compared wit h either MTBE columns or conventional distillation.