Robust Cascade Control for Chemical Reactors: An Approach based on Modelling Error Compensation

In this work, a robust model-based cascade control scheme for composition regulation in chemical reactors is proposed. The controller is based on a two loop control in a composition-temperature configuration. State-observers are introduced to provide robustness to the controller via the estimation of lumped model uncertainties. The second loop is introduced with a favorable choice of the Arrhenius equation as a virtual control input. The control design is illustrated based on two cases studies, a tubular reactor exhibiting two temperature dynamics (quasi-linear and hot-spot) and a CSTR presenting multiple steady-states. Numerical results indicate that proposed controller is robust in the face of external disturbances, operation changes, and model uncertainties.