Organosolv revisited – biomass valorization with new perspectives

摘要

This study reinvestigated the well known Organosolv concept aiming at maximum lignin output using scCO2 asco-solvent. Lignin is a still underestimated natural resource with potential application in the near future. The useof N-modified lignins as soil improvers was considered being one of the most interesting utilizations in responseto progressive desertification in parts of the world. The presented process uses rye straw as a renewable sourceachieving up to 70% delignification with lignin purities of 80-85% and nitrogen contents of up to 4%. Thenitrogen enrichment was achieved by thermal treatment of rye straw under alkaline Organosolv conditionssimultaneously using aqueous NH4OH as nitrogen source and supercritical carbon dioxide as pulping additive.The effectiveness of the used supercritical carbon dioxide could be demonstrated with a model substance study.Apocynol was used as a representative lignin model showing a significantly faster degradation in the presence ofscCO2 which is in accordance to a 40% lower Arrhenius activation energy.