Importance of Distribution Statistics in the Characterisation of Chip Quality, 1996 Pulping Conference Proceedings

Gordon Broderick & Elizabeth Cacchione

Noranda Technology Ctr

Yves Héroux

McGill University

In order to identify the wood chip dimensions critical to pulp quality, a number of low-yield Mg bisulphite cooks have been performed at uniform conditions on separate chip length functions. Each chip fraction was examined manually to determine actual length, width and thickness distributions. Handsheet test results showed that the pulp quality obtained from the shorter R1/4” function could match or exceed that obtained using the R 3/4” chip fraction . Statistical analysis performed on the distribution characteristics indicated that tensile strength is significantly affected by paprameters - describing the non-uniformity in chip width and thickness. Distribution statistics for chip length also have an important effect on tear index. These variations in pulp quality appear linked to the uniformity of the cook since the selectivity of the delignification was also found to vary as a function of chip size distribution at the same overall yield.