Temperature control of polypropylene thermal cracking reactor by input/output linearization with two-degree-of-freedom structure

This work presents a model-based controller with a two-degree-of-freedom (2DOF) control structure for handling bed temperature of polypropylene cracking in a fluidized bed reactor. The control system is formulated based on a developed dynamic mathematical model of the reactor. The developed control system consists of an input/output (I/O) linearizing controller for tracking the desired output, a high-gain controller for disturbance rejection and an observer with linearizable error dynamics for compensated state variables from the measured outputs. The control performances of the method are evaluated through simulation under process uncertainties and model mismatch by comparing with a 1DOF input/output controller and a proportional-integral controller. The results show that the proposed controller based on 2DOF scheme can improve the control performances both process uncertainties and model mismatch.