Decoupled Pid Controllers for Tracking Optimum set Point in Multiple-input-multiple-output (mimo) System of Ethylene Glycol Production

Abstract

Control of ethylene glycol (EG) production involves highly interacting parameters which disrupts and degrades controllers’ performance. In this work, a validated model is used to attain and maintain the optimum EG flowrate and reactor temperature. Effective Relative Gain Analysis (ERGA) method is applied in determining the pairing of each manipulated (MV) and controlled variables (CV). The best pairing is identified as MV1-CV1/MV2-CV2. Sensitivity analysis are performed to identify the stability and controllability of the closed loop systems. The conditioned number (C) and Morari Resilience Index (MRI) calculated are 1.47 and 0.679, respectively. Decoupling method within Simulink Matlab environment is used to reduce/eliminate loop interactions for increased quality of Proportional-Integral (PI) controllers in controlling EG production. The results show that the decoupled PI controller (with proper/tight control boundary) shows significant improvement in control performance. Keywords: Ethylene Glycol (EG), Multiple-Input-Multiple-Output (MIMO), Decoupler, Control, Effective Relative Gain Analysis (