DESIGN OF AN ON-LINE TITRATOR FOR NONLINEAR pH CONTROL

A new on-line titrator for pH control has been developed. The on-line identification method generates an estimate of the inverse titration curve as a continuous smooth function eliminating the need for selection of the important break points of the titration curve. The time required to obtain the titration curve in the spanned pH range is approximately twice the settling time of the titrator and thus no significant identification lag is introduced. The results of the titrator are used directly to linearize the pH process output enabling the application of a simple and yet effective linearizing feedforward-feedback control strategy.