Abstract
In distillation, transient behavior cannot be completely eliminated, even with the application of advanced controllers, because the operation in stages imposes the propagation of corrective action throughout whole unit. In previous studies, a control strategy was proposed that uses a combined action between reboiler and heating tray in stripping section of the column aiming to minimize transient operation in distillation. In this work, using the commercial simulator Aspen HYSYS Dynamics, the application of this control strategy was evaluated and it was compared with one testing a distributed cooling action applied to a tray of the rectifying section. Both strategies were also compared with a conventional dual temperature control system when disturbances in the feed temperature were performed. Results had demonstrated a reduction in transition time in bottom and top temperature control loop when distributed strategy was use, either when heating or cooling actions were taken. Internal variables were analyzed in order to verify alterations in flows. Steady state profiles of temperature and ethanol composition were not modified in relation to that obtained with conventional actions, indicating that the proposed distributed strategy only influences transition time.
