Optimization and control of pervaporative membrane reactor

Abstract

The hybrid process integrating chemical reaction with membrane separation has been increasingly received much interest. In this work, a pervaporation-based reactor has been studied for esterification of acetic acid and butanol. The combination of pervaporation with a conventional esterification process can shift the chemical equilibrium of esterification by removing water from the reaction mixture and, therefore, increases the yield of desired product. The effect of operating parameters on thermodynamic equilibrium of esterification is taken into account in the reactor model. Since a reactor temperature is one of key factors, which influences both the reaction and pervaporation process through the reaction rates and membrane permeability, in order to operate the pervaporative membrane reactor efficiently, optimization framework is formulated to determine the optimal temperature policy. The maximization of the desired product is considered as an objective function in the optimization problem formulation subject to other process constraints, which is solved by the sequential optimization approach. A generic model control (GMC) coupled with an extended Kalman filter is implemented to track both optimal temperature set point and optimal temperature profile obtained in the off-line optimization. Application of these control strategies to control the pervaporative membrane reactor shows that the proposed control strategy provides good control performances in a nominal case. The GMC coupled with Kalman filter has been found to be effective and robust with respect to changes in process parameters.