Accurate and Sustainable Bleach Plant pH Control, 2000 Pulping / Process & Product Quality Conference Proceedings
J. Perala--With Elemental Chlorine Free (ECF) bleaching the importance of a good pH control in chemical pulp bleaching has become a critical factor for a successful bleach plant operation. This is especially true in D stages, where operating in incorrect pH range can significantly reduce the bleaching efficiency of chlorine dioxide, thus increasing the cost of bleaching and effecting to pulp and effluent quality. This paper describes a concept for accurate and sustainable pH control. It is operating in a Canadian pulp mill, where automatic filtrate samplers are used in every stage of the bleach plant. The pulp pH is measured from a continuous fiber free liquid sample drawn from the process by the sampler. From this same sample pH is also analyzed periodically in the laboratory. Laboratory test values are used by the proprietary calibration algorithm to calibrate and validate the pH measurement.
Accurate and Sustainable Bleach Plant pH Control, 2000 Pulping / Process & Product Quality Conferenc
