Design and Simulation of Hierarchical Control of Two Continuous Stirred Tank Heater in Series

Background/Objectives: The present investigation was carried out to study the application of process control hierarchy to design an optimal control system for a two continuous stirred tank heaters in series (2-CSTHs). Methods/Statistical Analysis: The optimal control strategy of the 2-CSTHs is designed in a hierarchy of three level structures which employs optimization in the real-time optimization (RTO) control level, feedback control scheme in the regulating control level and sensors, pumps and control valves in the measurement and actuation level. All these levels should be coordinated and require information transfer. The proposed optimal control system of the 2-CSTHs was simulated using MATLAB/ SIMULINK and HYSYS. Findings: The simulation results show that the PID feedback closed-loop of the 2-CSTHs for level and temperature controllers are able to achieve satisfactory performance for servo and regulating control. Simulation on the RTO algorithm also yields results which indicate that the non-derivative technique is an efficient algorithm in minimizing the square of tracking error of temperature in both tanks of the 2-CSTHs. Application/Improvements: The non-derivative algorithm has the advantage over other algorithms in the family of ISOPE algorithm for not requiring process derivatives which make it attractive for industrial applications.