On-Line Dewatering Measurement at the Paper Machine’s Wet End Provides New Insight for Better Retention-Aid Control, 1999 Papermakers Conference Proceedings

Sylvain Renaud & Bertil Olsson BTG Pulp & Paper Technology AB Wet-end chemistry is a fundamental element that relates directly to final paper properties. A better dosing of retention aid chemicals and drainage aid chemicals results in increased paper machine efficiency, stabilization of the wet-end, better sheet formation, and lower operating costs. An important condition for better chemical dosage is continuous and reliable automatic measurement. The Dewatering Rate Analyzer, a new on-line dewatering measuring device, has been introduced to the paper industry. The instrument is designed to measure the dewatering capacity of the head box pulp suspension. Its measurements are straightforward and very representative of process variation. The uncomplicated instrument permits on-line measurement of pulp drainage capacity and monitoring of chemical efficiency at the wet end. Most retention chemicals act also as dewatering agents and, therefore, measurements of pulp drainage are of great importance. This paper presents the concept of dewatering measurement, the laboratory measuring methods most commonly used by papermakers, the new on-line analyzer and some control solutions.