Online estimation of impurity ion concentration in solution purification process*

Online estimation of impurity ion concentration is critical in the optimization and control of solution purification process. Online determination equipments of metallic ions are usually expensive and difficult to maintain in hostile production environments. Oxidation-reduction potential reflects the status of impurity removal reaction and can be monitored online continuously by cheap and easy maintainable oxidation-reduction potential meter. This paper proposed an online estimation approach for impurity ion concentration by taking advantage of the online measurable property of oxidation-reduction potential. The proposed method utilized both domain knowledge, offline day-by-day routine production data and online data. Moving horizon estimation method is used in the estimation. The effectiveness of the proposed approach is illustrated by an experimental study.