Design guidelines for solid-catalyzed reactive distillation systems

In this paper we discuss design guidelines for solid-catalyzed reactive dis tillation systems. The guidelines are used to generate initial estimates fo r column pressure, reactive zone location, catalyst mass, reactant feed loc ation, reactant ratio, reflux ratio, column diameter, number of equilibrium stages, and packed height. They form a part of a methodical design procedu re that makes extensive use of both nonequilibrium (rate-based) and equilib rium-stage simulation models. Important choices prior to design include sel ection of reliable thermodynamic and reaction kinetic models. We tested the guidelines for two etherification systems and validated them experimentall y for a hydration reaction. The results from a case study, the manufacture of tert-amyl methyl ether, are shown here. Superimposing reaction on separa tion leads to unique design trade-offs. Thus, column diameter depends both on maximum vapor velocity and on packing catalyst density, reactant ratios are a function of conversion and azeotrope formation, the operating pressur e affects the relative volatility, chemical equilibrium, and reaction rate (reactive zone temperature), and the reflux ratio impacts both separation a nd conversion. The guidelines and procedures presented here simplify the de tailed reactive column design considerably.