Deoxygenation of Biomass Pyrolysis Vapors via in Situ and ex Situ Thermal and Biochar Promoted Upgrading

Production of stable, partially deoxygenated biomass pyrolysis bio-oils is needed to increase the fungibility of bio-oil for refining into fuels and chemicals. While zeolite catalyzed upgrading is commonly used to produce such liquids, the associated catalyst deactivation is a significant hurdle to overcome. Our group has previously reported on the thermal deoxygenation of pyrolysis vapors that is carried out under an atmosphere partially consisting of recycled tail gas and without the use of externally added catalysts. In this study, thermal deoxygenation was further studied in a new and scaled-down (laboratory scale) pyrolysis system to allow for a systematic study and to better understand the factors affecting vapor deoxygenation. Temperature excursions from the fast pyrolysis temperatures near 500 oC and/or the catalyzing effect of accumulated bio-char were hypothesized to be potential key parameters affecting vapor deoxygenation. Therefore, experiments were conducted by utilizing a recycled gas and i...