Simplified Design of Batch Reactive Distillation Columns

Abstract

This work proposes a simplified methodology for the analysis and design of reactive batch distillation columns based on the McCabe-Thiele method for reactive continuous columns and on the concept of a reactive difference point. To extend the application of the concept of a reactive difference point for reactive batch distillation columns, expressions for the McCabe-Thiele operating line and for the dynamics of the reboiler in the reactive case have been derived; two cases are considered depending upon the phase in which reactions occur (i.e., liquid or vapor). We also provide an approach to the derivation of an expression to calculate the molar turnover flow rate by considering each reactive distillation plate as a combined system of a conventional equilibrium stage linked to a chemical reactor (phenomena decomposition). Furthermore, we present our derivation of the Underwood equations (minimum reflux) for continuous and batch reactive distillation columns. Finally, five illustrative examples allow us to show that our results present reasonable agreement with those obtained through BatchFrac of AspenPlus.