NOVEL CHEMISTRIES ENABLE PULP MILLS TO RECOVER LOST WASHING EFFICIENCY

摘要

Brownstock washers in North America are routinely running well past design capacity and inefficiencies in washing have significant implications in operating costs as well as production capabilities. Brownstock washer operations impact pulp quality, chemical recovery, bleaching processes, paper machine chemistry, evaporator operations and production capacity. Optimizing washing efficiency is crucial to the economic health of a pulping operation. By improving washing performance without capital expense, mills have experienced documented benefits in excess of $1 million. This paper focuses on novel washing chemistries utilized to regain lost efficiencies common to overloaded washers. Defoamers and wash aids have a long history in the paper industry as process enhancement additives. From dealing with nuisance foam to improving washing efficiency, a wide range of chemistries have been utilized to improve productivity and reduce costs. As the mills in North America continue to push more tons through under-sized equipment, new and unique chemistries are needed to generate the performance required to maintain washing efficiency. Differences in defoaming and drainage chemistries are explained for process engineers and operations personnel. Additionally, examples of the efficiencies regained through successful selection and application of the novel defoamer chemistries are shared.