How does the torrefaction process affect the decomposition behavior of lignin in wood?

Torrefaction is a thermal treatment process that can enrich the lignin content in wood samples. The study compared the decomposition behavior of residual lignin in torrefied beech and Douglas fir wood with that of Klason lignin.

Torrefaction at 583 K for 50 minutes results in wood samples that are significantly enriched in lignin, with decomposition behaviors that closely match those of Klason lignin. The thermogravimetric curves of residual lignin in torrefied wood and Klason lignin are almost identical above 583 K, confirming that Klason lignin can be used as a good model compound for native lignin in wood. This finding is important for developing accurate kinetic models for the pyrolysis of torrefied wood.