Canadian Journal of Chemical Engineering, Vol.96, No.4, 912-925, 2018
SIMULATION AND CONTROL OF MEMBRANE REACTORS FOR CATALYTIC REDUCTION OF DISSOLVED OXYGEN FROM WATER
Removal of dissolved oxygen (DO) from water has gained much attention in recent decades to prevent different problems such as corrosion, bio-fouling, and performance degradation in many industries. The traditional physical and chemical methods for DO removal have found wide application in industries. However, physical methods have low efficiency and chemical methods often produce undesirable products. Therefore, catalytic reduction by hydrogen has been regarded by a variety of industries recently. In this study, catalytic reduction of DO from water is examined using membrane reactors. The mathematical model of this system is developed while considering the axial dispersion, membrane permeation, and chemical reaction. The model is solved in steady state mode and the effect of various parameters on the DO removal is investigated. The results of steady state mode are used as initial conditions for solving the model in dynamic mode. The impact of operating conditions such as water flow rate, DO concentration of influent water, hydrogen flow rate, and hydrogen pressure on the performance of the DO process is studied. Results of the dynamic simulation suggest that hydrogen pressure is the best option to be used as a manipulated variable for control of effluent DO concentration. Finally, a PI controller is implemented to control the system. The closed loop responses indicate that a PI controller would perform well both in load rejection and setpoint tracking if it is tuned accurately.