Preliminary Design of Reactive Distillation Columns

A procedure that combines feasibility analysis, synthesis and design of reactive distillation columns is introduced. The main interest of this methodology lies on a progressive introduction of the process complexity. From minimal information concerning the physicochemical properties of the system, three steps lead to the design of the unit and the specification of its operating conditions. Most of the methodology exploits and enriches approaches found in the literature. Each step is described and our contribution is underlined. Its application is currently limited to equilibrium reactive systems where degree of freedom is equal to 2 or less than 2. This methodology which provides a reliable initialization point for the optimization of the process has been applied with success to different synthesis. The production of methyl-tert-butyl-ether (MTBE) and methyl acetate are presented as examples

Design of kinetically controlled reactive distillation columns

Reactive distillation is an emerging technology that has great potential as a process alternative for carrying out liquid-phase chemical reactions. Systematic design methods for reactive distillation systems have only recently begun to appear, and so far these have been restricted to systems at chemical equilibrium. It is not always desirable, however, to operate reactive distillation columns close to reaction equilibrium conditions. In this dissertation we present a design procedure for kinetically controlled reactive distillation columns. We show that the amount of liquid holdup per stage has a significant effect on the design. The procedure is based on fixed-point methods. Using these methods we have developed an algorithm for calculating the minimum flows in a reactive distillation column as well as the number of stages required to achieve a specified conversion/separation. For the examples studied, we show that the minimum reflux ratio in a kinetically controlled distillation is equal to that for an equilibrium reaction. We also show how to choose specifications that will lead to feasible reactive distillation columns. We tested our design results against column simulations and found them to be in good agreement