Improved uniformity of the fibers liberated in a kraft pulp digester

Why is this important:

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.

Methods we use:

Single-chip delignification experiments will be followed by thorough analysis of the local structural and compositional delignification effects: partly delignified chips will be sectioned and every section structurally/compositionally analysed allowing for determination of concentration profiles of wood components within the treated chip.

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 time-resolved morphological information from tomography studies will enable a comprehensive insight into the origins of heterogeneous delignification effect and open up for developing strategies to minimize/control it.

Expected results and scientific impact:

An understanding of the underlying mechanisms resulting in non-uniform delignification effect will enable a more resource efficient process design along with improved quality control of the pulp and, thus, improved efficiency and competitiveness of pulp mills. In a broader perspective, this project will provide a new fundamental knowledge pertaining to characteristics of kraft delignification in general.

Project partners:

Chalmers, Stora Enso, Södra, SCA, Billerud, Valmet, Holmen
Sectioning of the partly delignified chip for characterization of local delignification effects.




Read more: