Improved uniformity of the fibers liberated in the kraft pulp digester 

This project sets out to elucidate mass transport characteristics during delignification of wood chips as a means of understanding and controlling non-uniform delignification effects, associated to low efficiency and poor property control in the current pulping processes. To obtain information on local variations of delignification effect in a wood chip, the treated chips will be sectioned and every section thoroughly characterized. Comparative studies on several wood species will allow a broader understanding of the morphological aspects pertaining to delignification behavior. The chips delignified under industrial conditions will also be included. The results will be complemented by real-time monitoring with X-ray tomography providing information on accompanying morphological changes (porosity, cell wall separation, etc). Combined knowledge on local structural variations with the 3D real-time morphological information will provide a comprehensive insight into the origins of heterogeneous delignification effects and open up for strategies to minimize/control it.