Recovery of Acetic Acid from Aqueous Solutions by Reactive Distillation

Abstract

The recovery of acetic acid by reactive distillation through esterification with methanol in the presence of ion-exchange resin as a catalyst has been investigated in detail. A kinetic expression that is valid under the conditions that prevail in a continuous reactive distillation column has been developed. The insensitivity of reaction rate to catalyst loading under certain conditions has been addressed. The recovery as high as 80% was realized experimentally for the feed concentration of 30% (w/w) in a laboratory column. Various alternative scenarios such as effect of reboiler duty, feed flow rate, and feed composition were covered in the experiments. The equilibrium stage model for reactive distillation predicts the performance well in agreement with the experimental results. The effect of changing various design and operating parameters, over a wide range, was also studied through simulation. The model predicts close to quantitative recovery (∼100%) with a properly designed column. Some feasible alternative configurations for a complete recovery system have been suggested.