Modelling of Reactive Distillation for Acetic Acid Esterification

Esterification reactions are limited by chemical equilibrium and therefore they are carried out commercially using either a large excess of one of the reactants or by removing one of the products continuously. The removal of one of the products continuously can be achieved by carrying out reactive distillation where reaction and separation are performed simultaneously. This work presents an approach for mathematical modelling and simulation of batch reactive distillation which can be used by design engineers to obtain key information such as composition and temperature variation as the reaction progresses with time, product composition and the quantity accumulated in the distillate and the most suitable reflux conditions needed for high product separation rates. The process unit studied consists of a batch reactor with single stage distillation and a condenser. The mathematical model considered material balance equations, equilibrium relationships, summation equations and energy balance equations. The model was simulated for acetic acid and ethanol esterification reaction. The reactor composition variation in modelling and simulation results show a decrease in acetic acid and ethanol reactant compositions with time while ethyl acetate and water compositions show an increase. The ethyl acetate mole fraction in the condenser increases as the reflux ratio increases.

ENGINEER, Vol. 48, No.04, pp. 17-23, 2015