Modeling of a Batch Catalytic Reactive Distillation Process Using a Multi-Scale Approach of Pore Diffusion and a Non-Equilibrium Rate Based Model

Reactive distillation is carried out to produce methyl acetate from acetic acid and methanol using Indion180 as a solid ion-exchange resin catalyst in a simple distillation apparatus. Unlike the reboiler-column combination, a simple distillation apparatus is used to conduct reactive distillation where the vapors are condensed and collected as the catalytic reaction is proceeding in the reboiler flask. The aim is to quantitatively measure the distillate’s purity in terms of the methyl acetate’s mole fraction in it. The composition of instantaneous distillate, cumulative distillate, and of the reactant mixture in the reboiler is measured continuously.  The temperature in the reboiler as well as the electrical energy supplied to it is also measured as a function of time. A non-equilibrium evaporation rate-based model is proposed to predict the kinetics of the distillate and reboiler composition as well as the temperature. The reaction rate of the solid-catalyzed esterification process is modeled as per the pore diffusion model for the heterogeneous part as well as the homogeneous reaction. No previous studies are available with this concept of reaction kinetics in combination with the evaporation rate for reactive distillation. The experiment is conducted in simple distillation mode with nearly a constant heat input rate and developed a mathematical model for the obtained distillate composition. The overall model of reactive distillation is validated with the help of very few adjustable parameters found by minimizing the error between experimental data and model prediction.