The effects of noble metal catalysts on the bio-oil quality during the hydrodeoxygenative upgrading process

A hydrodeoxygenation reaction (HDO) of bio-oil was conducted with Ru/C and Pt/C. Yield of heavy oil as a target product was influenced by reaction temperature irrespective of catalysts. HDO gave rise to an improvement in the following oil properties: water content, heating value, viscosity, acidity and oxygen level. Due to the de-moisturization, 61.6-97.2% of water decreased. Ru/C and Pt/C led to deoxygenation with increasing temperature. Especially, the heavy oil obtained from 350 degrees C with Pt/C was deoxygenated up to 78.2% and had a higher heating value (27.8 MJ/kg) than the bio-oil (17.3 MJ/kg). After HDO unstable/unsaturated compounds (acetic acid, furfural, vanillin and levoglucosan) in bio-oil were converted to esters, ketones and saturated phenols. According to the reusability test of HDO catalysts chars were deposited on the surface of catalysts, which could be the reason for the deactivation of catalysts. The Pt/C was denoted as having high durability and thermal resistance. (C) 2015 Elsevier Ltd. All rights reserved.