PH CONTROL USING AN IDENTIFICATION REACTOR

pH control plays an important role in chemical processes. However, pH control has been recognized as a very difficult control problem becaus e of its nonlinearities and time-varying characteristics. A new pH con trol strategy using an identification reactor is proposed to incorpora te both the nonlinearities and time-varying characteristics of the pH process. In this study, an equivalent titration curve between the pH v alue and the scaled total ion concentration of the titrating stream is obtained from the identification reactor, and the pH value is control led in the main reactor using the obtained equivalent titration curve. A simple stability analysis is used to determine the tuning parameter s of the PI controller, Simulation results show that the proposed cont rol strategy can handle both the nonlinearities and time-varying chara cteristics.