Rigorous design and control of thermally integrated pressure‐swing reactive distillation process for isobutyl acetate production considering the effect of column pressures

Abstract

By studying the effect of pressure on relative volatility, azeotrope composition, and net reaction rate, a rigorous pressure-swing thermally integrated reactive distillation (PST-RD) process for isobutyl acetate synthesis is proposed. The steady-state and dynamic characteristics of the PST-RD process are evaluated based on Aspen and Aspen Dynamic. Steady-state optimization results show that the energy consumption and the total annual cost (TAC) reduced by 42.32% and 34.20% compared with the conventional two-column process, respectively. Subsequently, two control structures of the PST-RD process under a rigorous model are developed and evaluated by large disturbances in throughput and feed composition. Dynamic simulation results show that peak dynamic transients can be effectively reduced by adding a Q/F feedforward control structure. Furthermore, the effective heat integration of high-pressure (HP) and low-pressure (LP) columns can be realized by implementing composition/pressure cascade control when the capacity of the LP column increases.

An investigation of the interactions between system characteristics and controllability for reactive distillation systems

“…Feedforward control has not often been considered, however, in a relevant contribution by Mahindrakar and Hahn (2016), feedforward control of a benzene hydrogenation system was found to be effective as long as time delay in composition measurement was small. In a different contribution, feedforward control schemes were applied for the control of a pressure-swing heat integrated reactive distillation process for methanol production under feed flow rate and composition disturbances (Zhang et al 2020).…”

“…Both disturbances were introduced as sharp ramps over 500s and were chosen as they are commonly considered in relevant academic contributions (e.g. Agachi 2006, Pham and Engell 2011, Zhang et al 2020 as well as often encountered in real-plant operation. However, for the reactive distillation systems considered which are designed for 1:1 feed ratio (i.e.…”