Diagnosis of Abnormal Situations in a Continuous Solution Polymerization Reactor

This work presents results on the problem of robust on‐line diagnosis of abnormal situations in the case of the free‐radical solution polymerization of styrene in a continuous well‐mixed reactor operating under feedback control. The control system is constituted of a model predictive control strategy in conjunction with a ratio control law. The proposed fault diagnosis system is based on an open‐loop approach, which uses a linearized model of the polymerization process for the implementation of a bank of reduced‐order unknown input observers. Each observer is designed to detect changes in a particular process parameter, external disturbance or malfunctioning of sensors and actuators. Fault isolation is obtained through a structured residual approach; meanwhile, fault estimation is performed using the degree of freedom remaining in the observer design. The effectiveness of the proposed technique is verified through numerical simulations carried out on a well‐defined industrial styrene polymerization benchmark.