Hydrodeoxygenation of Oxidized and Hydrotreated Bio-oils to Hydrocarbons in Fixed-bed Continuous Reactor

The physical and chemical properties of raw bio-oil, two oxidized bio-oils, and hydrotreated bio-oil were compared before and after catalytic hydrodeoxygenation using sulfided CoMo/γ-Al2O3 catalyst. Following continuous hydrodeoxygenation, the organic liquid products from treated bio-oils and raw bio-oil were compared for higher heating value, oxygen content, water content, and viscosity. In addition, Fourier transform infrared spectroscopy and gas chromatography/mass spectrometry were employed to identify functional groups and chemical species, respectively. Fresh and spent catalysts were characterized by nitrogen adsorptiondesorption for surface area and pore properties. The degree of coking of the spent catalysts was analyzed by thermogravimetric analysis. Hydrodeoxygenation of hydrotreated bio-oil (HB) gave the longest reaction time on stream of 780 min, the least coking amount of 20 wt%, and the highest hydrocarbon selectivity of 70% up to 720 min of reaction time on stream. Moreover, organic liquid products from HB showed relatively stable properties such as low oxygen content, water content, and viscosity over a longer period of reaction time on stream.