Kinetics-Based Model for Predicting Kappa Number During Batch Kraft Cooking, 2001 Pulping Conference Proceedings

Q. Luo, H. B. Liu, J. Y. Zhu, X. S. Chai--A kappa number model was derived from the kinetics of delignification in batch kraft cooking as Ka= A-Bln[(H - Hb) EA(superscript R, subscript b], where Ka is kappa number, Hb and EAb are the H factor and effective alkaline concentration at the beginning of bulk delignification at which acidic neutralization reactions have been completed, and A, B, R are constant and can be determined through data regression. The derived model avoids the complex alkali reactions in the initial phase of delignification. The model only requires in-process sampling of the pulping liquor to analyze effective alkali concentration for the determination of EAb using the H factor method developed in this study. Comparisons between the predicted kappa numbers and those measured in different laboratory pulping experiments of loblolly and masson pine indicate that the model is accurate and robust. Therefore, the model has practical importance for predicting pulp kappa number during batch kraft cooking. Key words: Kappa number, batch kraft pulping, effective alkali, H-factor, Model.