Comparative control study of a simulated batch rectifier

This article proposes a nonlinear control strategy for a batch rectifier. The hybrid control strategy comprises a state estimator, namely Luenberger-like nonlinear estimator (LNE) and the feedback linearizing controller (FLC). The observation scheme aims to estimate the imprecisely known parameter based on the available measurement. For the representative distillation unit, the state predictor is formulated using only a component material balance equation around the condenser–reflux drum system. It clearly indicates the existence of a process/model mismatch and this discrepancy is efficiently taken care of by the corrector part of the LNE. In the subsequent phase, the FLC is synthesized for the example system. The derived nonlinear FLC–LNE controller shows better performance compared to a traditional proportional integral (PI) law. The simple structure, straightforward design and good performance make this nonlinear controller attractive for online use.

► A nonlinear control strategy is proposed for a batch rectifier.
► The hybrid controller comprises the LNE estimator and FLC controller.
► The proposed controller outperforms a traditional PI law.