Controllability assessment and intentional operation of extractive distillation configurations with preconcentration

There has always been an opaque link between economic and control performance in process intensification. In fact, whether the excessive interactions produced by intensification are detrimental or beneficial hinged upon the specific circumstances. This gives rise to a systematic approach to controllability analysis, which is discussed on two extractive distillation examples with preconcentration. The detailed frequency domain dependent open-loop controllability analyses are first carried out to investigate set-point tracking and load rejection performance. The closed-loop validation in time domain is then performed. The results show that the remarks of the open-loop analysis are correct in determining the control structure and are ambiguous in loads rejection. Further, a surrogate-based intentional control strategy is applied, faster in response and greater in robustness than the conventional fixed sensitive tray temperature strategy, well similar in energy consumption, under simultaneous disturbances in multiple operation conditions and product specifications.