Optimization and control of energy saving side-stream extractive distillation with heat integration for separating ethyl acetate-ethanol azeotrope

Abstract

Currently, limited efforts have focused on the multi-objective optimization and effective control of the side-stream extractive distillation processes (EDS). Herein, the EDS and a heat-integration scheme (EDSH) are proposed for separating the minimum-boiling azeotropic mixture ethyl acetate (EtAC)-ethanol (EtOH). Firstly, the conceptual design by residue curve maps is demonstrated for the EDS. Following which, the genetic algorithm (GA) optimization is carried out to minimize the total capital investment cost (CAP) and the annual energy cost (ENR). Optimal scheme under the product purity constraints is then obtained from the Pareto front. And the EDSH scheme is shown with less TAC and CO2 emission. Therefore, an improved control structure CS3 combining the composition-(RR1/SIDE) cascade and feedforward strategy is developed to achieve decent dynamic responses for the EDSH. The anti-disturbance capability of different control structures in terms of the transient deviation and offsets are compared with the assistance of the integral absolute error.