Brownstock washing fundamentals: Enhancing drainage through chemistry — Part 2

The drainage of filtrates during mat formation in a brownstock washer directly impacts the washer’s productivity and indirectly affects its efficiency. In this paper, the role of entrained air on filtration through a formed mat during displacement as it occurs in brownstock washing was investigated. It was shown how chemical treatments, such as wash aids and fiber surface chemistry, influence air entrainment and, thereby, washer productivity and efficiency. By minimizing air entrained within a formed mat, displacement filtration rates and wash ratios were shown to improve. With this knowledge, washer operations can be improved through the design and selection of better treatments.