Control and estimation algorithms for physico-chemical models of pH-processes in stirred tank reactors

Publisher Website
Google Scholar
Abstract
A new approach to pH-process modeling and control based on the basic physicochemical laws is presented. The model includes hypothesized chemical species, the dissociation constants of which can be chosen by static fitting with the aid of so-called titration curves of real liquid samples. With respect to the chosen concentration variables of the species, the mixing dynamics of the process is linear. The pH-variables have a highly non-linear momentary relation to the concentrations, but with the aid of a certain transformation a linearity can be achieved. In control applications the unknown concentrations are estimated from pH measurements by a linear algorithm constructed via a deterministic formulation. The estimated concentrations are used to determine the input to the pH-controller. Several simulations of the algorithms and comparisons with the conventional feedback pH-control were performed and are presented. Simulations using samples from a real industrial process were made. [The acidity of liquid, which is normally indicated by a pH value, is an important object of control in industrial processes, water treatment and wastewater treatment.].

This publication has 3 references indexed in Scilit: