Processanpassade biobaserade sortiment genom nyutveckling av ångexplosionsprocessen

Purpose and goal

The overall objective of the project was to reduce the recondensation of lignin during steam-explosion of softwood bark and to increase the yield of fermentable sugars during enzymatic hydrolysis by binding dissolved lignin carbocations that otherwise block the availability of the substrate for enzymes. A subsequent pelletization then simplifies the industry´s use of bio-based raw material. The education of an industrial Ph.D. student ensures high-class education and knowledge exchange between industry and academia.

Expected results and effects

The expected effect of the addition of carbocation binders as an inhibitor of lignin recondensation was absent, which contradicts previous results from laboratory experiments and on a smaller pilot scale. Thus, the bark´s inherent high content of lignin remained even after the steam explosion treatment and a percentage increase in the substrate due to the breakdown of hemicellulose. The information requested by the host company on the possible effect of pre-drying the raw material before the steam-explosion showed no such effect.

Planned approach and implementation

The steam explosion tests were carried out at the host company under industrial conditions in a continuous process. Obtained substrates underwent enzymatic hydrolysis. The organic composition of raw material, steam exploded substrate and enzymatically hydrolyzed product was analyzed to determine the effects of carbocation binders as well as various factors in the steam-explosion process and enzyme treatment. The host company showed a strong commitment to the implementation of the project and to the supervision of the doctoral student.