The prediction of pulp yield using selected fiber properties

The present study is dealing with the question how the major yield-controlling components in pulp (i.e., hemicelluloses and lignin) alter the behavior and/or properties (e.g., dimensions, flexibility, sugar content) of the fibers. The hypothesis should be verified that certain fiber properties can be used as marker for yield information. Pine and maple wood were digested under specific conditions to produce unbleached pulps with two different lignin contents per method. Screened pulps were chemically analyzed using a new NMR technique for carbohydrates, and the fibers were fractionated using a modified Bauer McNett classification. Pulp yields were related to the pulping methods in the sequence: polysulfide > kraft > biokraft > soda. Carbohydrate analysis revealed that the glucose content (glucose method) was related to the pulping yield. Certain fiber properties (fiber width and coarseness measured directly from the screened pulps) also provided close correlations with the pulp yield. The arithmetic average fiber length and width of the R-14 Bauer McNett screen was a significant predictor of yield at the 95% confidence level, with a mean error of 0.43%.