Evaluación del sistema de control del sistema de control post- electrolisis de una planta cloro- soda para el tratamiento de efluentes salobres

Abstract

CONDITION FOR PROJECT PUBLICATION. This project evaluates and optimizes the post-electrolysis control system of a chlor-alkali plant, aiming to improve the dynamic stability of the level, pH, and oxidation–reduction potential control loops, while reducing chemical reagent consumption and associated operational risks. The central hypothesis states that improper controller tuning is the primary cause of the observed instability; therefore, an adequate tuning strategy leads to a more robust and efficient process operation. The justification is based on the need to ensure stable, safe, and economically viable brine treatment prior to recirculation. The project development was carried out through step-response tests in plant conditions, dynamic process modeling using transfer functions, and simulations performed in MATLAB/Simulink. Classical tuning methodologies such as IMC-Lambda, AMIGO, ITAE criteria, and gain-scheduled control were applied, considering stability and robustness requirements. System identification yielded models with fit percentages exceeding 95% for the level and ORP loops, while achieving a 31% reduction in monthly metabisulfite consumption and 21% in caustic soda. In conclusion, optimization using scheduled gains, IMC–Lambda, and Surge Tank improved operational stability (ITAE and Bode), reducing chemical costs and manual interventions in MBS preparation.. Keywords: automatic control, Chlor-alkali process, dynamic stability, process optimization