Computers & Chemical Engineering, Vol.126, 292-303, 2019
Composition/temperature cascade control for a Kaibel dividing-wall distillation column by combining PI controllers and model predictive control integrated with soft sensor
Kaibel dividing-wall distillation column (KDWDC) is a very effective distillation process intensification technology. However, the misgivings of controllability problems impede its industrialization. Therefore, three feasible control schemes are studied in this paper, including the composition/temperature cascade control scheme with PI controllers in the lower layer and MPC in the upper layer (PI-MPC), the PI-MPC scheme with a composition estimator (PI-MPC-CE), and the PI scheme with pure temperature controllers. In the PI-MPC scheme, the MPC can deal with the complicated dynamics of the KDWDC, while the PI controller can quickly stabilize the KDWDC. The PI-MPC-CE scheme can continuously predict the primary controlled variables from the easy-to-access auxiliary variables. Dynamic performances prove that the PI-MPC-CE scheme are better than the PI and PI-MPC scheme with lesser number of oscillations, shorter settling times, and reduced maximum and steady-state deviations. Besides, it is very promising because it disposes of the continuous real-time composition detection. (C) 2019 Elsevier Ltd. All rights reserved.