Model ‐based fault diagnosis and fault tolerant control in safety‐critical chemical reactors: An experimental study

This study investigates a fault‐tolerant control (FTC) approach for continuous stirred‐tank reactors (CSTR), emphasizing the importance of timely interventions to ensure operational safety under fault conditions. A systematic methodology combining residual‐based fault estimation and Dynamic Safety Margin (DSM) monitoring is developed to guide the activation of a backup solvent injection strategy (“Plan B”). We introduce the concepts of critical fault magnitude and critical time, which provide explicit criteria for assessing when the nominal controller alone is insufficient. Integrating these concepts, we propose a unified FTC decision‐making framework to activate Plan B promptly. Experimental results confirm that this combined strategy robustly maintains the reactor within its safety constraints, accurately tracks setpoints, and effectively manages faults of varying magnitudes. The approach presented herein provides clear, practical guidelines for enhancing safety and reliability in chemical reactor operations.