Insights in the hydrotreatment of fast pyrolysis oil using a ruthenium on carbon catalyst

The use of Ru/C (5%-wt.) as a catalyst for the hydrogenation of fast pyrolysis oil was explored at 350 °C and 200 bar pressure in a batch reactor set-up with the main objective to determine the effect of the reaction time on the oil yield and elemental compositions of the product phases. Highest oil yields (65%-wt.) were obtained after 4 h using a 5%-wt. intake of catalyst on fast pyrolysis oil. Longer reaction times lead to a reduction of the oil yield due to the formation of gas phase components (methane, ethane, propane, CO/CO2). A solvent–solvent extraction procedure was applied to gain insights into the molecular transformations during the catalytic hydrotreatment experiments. It appears that specifically the carbohydrate fraction is very reactive. The observations are rationalized by a set of reaction pathways for the various product phases.