Heat-integrated pressure-swing distillation process for separation of the maximum-boiling azeotrope diethylamine and methanol

Abstract

Abstract The steady-state economics and dynamic controllability of heat-integrated pressure-swing distillation (PSD) processes are explored by taking the separation of maximum-boiling azeotrope diethylamine and methanol as demonstrating example. Compared to the conventional process, the B-E configuration (hot stream preheating the feed of high-pressure column) is attractive than others due to reducing 36.83% in energy consumption, 20.49% in CO2 emissions and 25.69% in total annual cost (TAC) and enhancing 49.48% in thermodynamic efficiency, respectively. Dynamic controllability of the economic efficient backward-integrated processes is also investigated by teaching the terminology of “simultaneous design”. The effectiveness of single-end control strategy is determined by the method of feed composition sensitive analysis, and a series of control structures are devised and assessed by the perturbations of feed flowrate and composition. The robust control scheme (CS5) with the ratio strategy to manipulate recycle stream flowrate is constructed to eliminate snowball effect and oscillation phenomena for partially case. It is also used to the combinational heat-integrated processes, and the differences of integral absolute error (IAE) are small between the alternative arrangements, demonstrating that the performance of single-end control scheme with the feedforward strategy of molar ratio reflux-to-feed (R/F) is robust and efficient.