Wet-End Chemistry - Case History Paper Machine Improvements Through Polymer Control, 1998 Process Control, Electrical & Info. Conference Proceedings

Wet-end chemistry is a fundamental factor that relates directly to final paper properties. A better dosing of retention aid chemicals results in increased paper machine efficiency, stabilization of the wet-end and lower operating costs. An important condition for better chemical dosage is a continuous and reliable retention measurement.

Nowadays, there are many retention control applications that present quantifying results. There are several benefits of polymer dosage control at the wet-end such as basis weight, thickness and moisture stabilization. This paper demonstrates the achievements due to better wet-end control based on continuous retention measurement and control. The paper describes and comments on the control strategy at STORA Hylte in Sweden that was put on control in March 1997. Other polymer closed loop control applications are also discussed.

Results are presented and polymer behavior explained. Finally, we quantify the economic benefits of automatic wet-end control, such as decreased chemical costs, increased paper machine efficiency and better paper quality.