PH CONTROL USING AN IDENTIFICATION REACTOR

Abstract

pH control plays an important role in chemical processes. However, pH control has been recognized as a very difficult control problem because of its nonlinearities and time-varying characteristics. A new pH control strategy using an identification reactor is proposed to incorporate both the nonlinearities and time-varying characteristics of the pH process. In this study, an equivalent titration curve between the pH value and the scaled total ion concentration of the titrating stream is obtained from the identification reactor, and the pH value is controlled in the main reactor using the obtained equivalent titration curve. A simple stability analysis is used to determine the tuning parameters of the PI controller, Simulation results show that the proposed control strategy can handle both the nonlinearities and time-varying characteristics.