Extended Impregnation Cooking of Norway Spruce: Effects on Pulping Uniformity and Pulp Strength Properties
2009 (English)Manuscript (preprint) (Other academic)
Extended impregnation kraft cooking is a demonstrated improvement of the kraft pulping process and offers a way to use softwood more efficiently. We demonstrate the possibility of producing Norway spruce (Picea abies) kraft pulp using a new cooking concept, producing a pulp that can be defibrated without inline refining at kappa numbers of approximately 90. The cooking concept uses the differences in reaction rate between the diffusion and consumption of hydroxide ions in the prolonged impregnation step. Lowering the impregnation temperature will favour the diffusion of cooking chemicals over neutralization reactions, thereby improving chemical distribution throughout the chips. Impregnation conditions in combination with cooking temperatures lower than those of conventional kraft pulping are demonstrated to produce pulp with a narrower kappa number distribution and comparable strength properties at a considerably higher yield.
Place, publisher, year, edition, pages
2009. , 40 p.
Uniform delignification, kappa number distribution, high-kappa-number pulp, reject, yield, tensile index, tensile stiffness index, SCT, starch multilayers
Paper, Pulp and Fiber Technology
IdentifiersURN: urn:nbn:se:kth:diva-11714ISBN: 978-91-7415-496-2OAI: oai:DiVA.org:kth-11714DiVA: diva2:280040
QC 201010142009-12-082009-12-082013-06-12Bibliographically approved