Defining nickel phosphides supported on sodium mordenite for hydrodeoxygenation of palm oil

Palm oil is largely produced in Thailand and sufficient to utilize as a biofuel feedstock through hydrodeoxygenation (HDO). In this work a new bifunctional catalyst consisting of nickel phosphide supported on zeolite mordenite in sodium form (Ni-P/NaMOR) was prepared by sequential impregnation and characterized extensively by several techniques to understand the reduction behavior, phases and distribution of nickel phosphides on the support. Nickel and phosphate precursors were transformed to Ni2P2O7 species by calcination and to a mixed phase between Ni12P5 and Ni2P by reduction. The phosphide species distributed in the zeolite cavities and external surface. The HDO of palm oil was tested in a down-flow stainless steel trickle bed reactor and the atmosphere was hydrogen. The mixed phase of nickel phosphides enhanced the HDO reaction. When tested by various temperatures and pressures, the optimum condition in this work was at 425 °C and 50 bar in which a complete of palm oil conversion, the largest HDO yield and selectivity toward C15-C18 alkanes were obtained. The green diesel and HDO yields from reduced Ni-P/NaMOR were larger than those from pure Ni2P and mixed Ni2P-Ni12P5. Interestingly, a small amount of isoparaffins was also observed likely due to the contribution of NaMOR support.