Hydrotreatment of corn stover bio-oil using noble metal catalysts

Hydrotreatment of corn stover bio-oil and its distilled fraction was performed using noble metal catalysts such as ruthenium and palladium on carbon support at 125 bar, 4 hour reaction time and 200 degrees C or 300 degrees C in a batch catalytic reactor. Results showed that ruthenium performed better at higher temperature (300 degrees C) and was more effective than palladium, giving about 25-26% deoxygenation. Higher yields (54-67 wt.%), higher H/C molar ratios (1.46-1.48) and lower O/C molar ratios (0.065-0.08) were obtained for the products from Ru-catalyzed processes at 300 degrees C. Analysis of the chemical composition of the products indicated that the major reactions involved hydrogenation of ketones to alcohols. Carbon dioxide, methane, ethylene and propane, were detected in the gas phase, indicating significant activity for this catalyst as compared to palladium. The hydrotreated product from the heavy distillate with ruthenium as catalyst at 300 degrees C had the lowest oxygen content (7.0 wt.%) and exhibited better product properties: lower moisture (2.6%), TAN (53 mg KOH/g sample), and the highest heating value (402 MJ/kg), making it a potential feedstock for co-processing with crude oils in existing refineries. (C) 2014 Elsevier B.V. All rights reserved.