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Abstract
“With more stringent requirements on discharge water quality and with escalating water treatment costs, water recycling within the paper mill is of growing importance. A serious problem resulting from more white-water recycling is reduced drainage and fiber or fines retention because of diminished polymeric additive performance. To provide better insight for overcoming polymeric additive performance problems, this work investigated interactions between pulp furnish and dissolved and/or suspended materials accumulating in whitewater systems. Effects of differing levels of materials carried over from mechanical (water soluble extractives), semichemical (neutral sulfite spent liquor), and chemical (kraft black liquor) pulping were determined with a cationic polyacrylamide and a polyethyleneimine. A drainage testing procedure was used, simulating dewatering processes on the paper machine, measuring drainage rate, fines retention and web dryness in response to vacuum. Results quantitatively show materials carried over from pulping processes reduce polymer effectiveness as a drainage and retention aid. With increasing levels of carryover, more polymer is required. Carryover affects polymeric additive performance similarly with both dried and never-dried pulp furnishes. The adverse effect of the additive on the web dryness in response to vacuum and on formation was decreased by carryover material.”
Keywords
Water quality,
treatment,
costs,
recycling,
drainage,
pulping,
polyacrylamide,
pulp mill effluent,
paper mills,
fines retention,
Polyethyleneimine
Citation
Wegner, T. H. 1984. Polymeric additive performance in closed whitewater systems. Proceedings, 1984 XXI EUCEPA International Conference, Torremolinos, Spain, vol. 2. Torremolinos, Spain : EUCEPA?, 1984: pages 437-451.
