Improved uniformity of the fibers liberated in a kraft pulp digester
| Reference number | |
| Coordinator | Chalmers Tekniska Högskola AB - Chalmers Tekniska Högskola Inst f Kemi- & kemiteknik |
| Funding from Vinnova | SEK 2 533 550 |
| Project duration | August 2021 - May 2026 |
| Status | Completed |
| Venture | The strategic innovation programme Bioinnovation |
| Call | PhD and post-doc projects for resource-smart industrial processes within BioInnovation |
Important results from the project
The project met its objectives. It provided a deeper understanding of the influence of morphology on the delignification of hardwood in the kraft pulping process. High porosity was shown to facilitate even delignification, which is also affected by temperature and concentration of cooking chemicals. Unique in situ X-ray tomography experiments (ForMax) enabled real-time studies of morphological changes as well as new insights into the impregnation process and masstransport in the wood.
Expected long term effects
New insights into how morphology influences local delignification effects, together with increased understanding of impregnation and transport pathways in wood, can contribute to improved process design and control. This would enable production of fibers with more uniform and controlled properties as well as a more resource-efficient production (of fibers, lignin and other products) in one of our most important industrial processes.
Approach and implementation
The project was structured around two different experimental setups. The initial part focused on investigating local delignification effects by dissecting chip pieces after different cooking times (and under different cooking conditions) and analyzing local variations in composition. The second part revolved around in-situ tomography studies conducted at ForMax and complementary cooking experiments to link morphological changes to variations in the chemical composition of the wood.