Production of renewable diesel from palm oil over NiMo/Al₂O₃ and Pd/C catalysts

Abstract

The production of renewable diesel from palm oil was studied over NiMo/Al₂O₃ and Pd/C catalysts. The reactions were carried out in a packed-bed continuous flow reactor under various conditions: temperature (300-375°C), pressure (400 -700 psig), H₂/feed molar ratio (15-30), and liquid hourly space velocity (0 .0 5 - 5 h⁻¹). The reaction pathway was proposed in this study. Moreover, long-term stability of a selected catalyst was also tested. The results show that palm oil was converted with high selectivity to hydrocarbons in the diesel range. In the catalytic deoxygenation of palm oil over NiMo/Al₂O₃, n-hexadecane (n-C16) and n- octadecane (n-C18) were obtained as the main products. In the case of Pd/C, n- heptadecane (n-C17) and n-pentadecane (n-C15) were obtained as the main products. Moreover, the corresponding fatty acids and fatty alcohols, were observed as intermediates of the reaction. The results indicate that the deoxygenation of palm oil is preferable via hydrodeoxygenation over the NiMo/Al₂O₃ catalyst while the reaction is preferable via hydrodecarbonylation over the Pd/C catalyst. For the stability testing, NiMo/Al₂O₃ still showed high conversion and selectivity to dieselrange hydrocarbon after 10 days.