Filtration Effects of Retention Chemicals in Save-All Disc Filter in News Production, 1999 Papermakers Conference Proceedings
Mr. Vesa Karvonen, Ms. Anne Leskinen, Mr. Markku Sillanpaa
This study concentrates on the effects of retention chemicals on the drainability of stock on the saveall disk filter. The goal was to compare four different retention chemicals using laboratory scale measurements and to choose the most suitable alternative, which gives maximum filtration rates and minimum solids content in filtrates. The best combination offered a 54 % improvement in drainability with 72 % less solids in the filtrate compared to a situation where no retention aid was used.
In full-scale trials, the drainability was measured by the speed of rotation of the filter and by the clear filtrate solids content, which was measured on-line. In the full-scale test, drainability improved from 18 L/m ² min to 28 L/m²min with a 6 ppm dose. At the same time, the separation efficiency calculated from white water solids content improved from 93.2 % to 95.9 %.
Filtration Effects of Retention Chemicals in Save-All Disc Filter in News Production, 1999 Papermake