Enhancing selective hydroconversion of C18 fatty acids into hydrocarbons by hydrogen-donors

Catalytic hydroconversion of C18 fatty acids with different hydrogen donors (H-donors) was carried out in a fixed bed reactor to intensify the selectivity for preparing renewable diesel through advanced hydrodeoxygenation technology. Two types of H-donors, condensed aromatics and hydroxyl compounds, were investigated and found that the H-donors had little influence on the yields of C15 and C16 hydrocarbons but significant for C17 and C18 hydrocarbons. Condensed aromatics have a positive effect on the yields of C17 and C18 hydrocarbons. Alcohols significantly enhance the selectivity for C18 hydrocarbon and suppress the selectivity for C17 hydrocarbon. The yield of C18 hydrocarbon is nearly doubled with 5 wt% ethanol. A multi-step mechanism is proposed to elucidate the phenomena.