Hardwood delignification - understanding chemistry and mass transport fundamentals

Important results from the project

The project met the set goals. It provided a deeper mechanistic understanding of both reactions & mass transport phenomena involved in the hardwood delignification. A new kinetic model emphasizing the role of diffusion was developed and, in collaboration with the parallel project "Improved homogeneity of delignified fibers", could describe the process within a woos chip. A new group of previously overlooked lignin reactions (impacting both kinetics and the final lignin structure) was identified.

Expected long term effects

New insights into delignification mechanisms (the importance of diffusion and the presence of previously overlooked secondary lignin reactions) may open up for improved process design and control that will enable a more selective and resource-efficient cellulose-lignin separation as well as improved control of lignin structures that are extracted, which is an important step in developing the process towards a diversified biorefinery with structural control when separating the wood components.

Approach and implementation

Experimentally, the project was designed around a series of pulping experiments carried out in a small flow-through reactor that allowed continuous sampling of the extracted lignin, which provided time-resolved information at different pulping conditions that could form the basis for kinetic studies and modeling. The lignin samples were quantified and structurally analyzed (NMR, chromatography) to obtain information on both diffusion and underlying chemical processes.

External links

https://resurssmarta.se/