Biodiesel production from different palm-oil feedstocks with hydroprocessing process over Ni-Mo/Al₂O₃and Co-Mo/Al₂O₃ catalysts

Abstract

In this research, relevant palm oil i.e. degummed palm oil (DPO), refined palm stearin (RPS) including hard and soft stearin are employed as feedstock to produce bio hydrotreated diesel. The reaction was performed in parallel small batch reactor under reduced pressure of 50 bar catalyzed by sulfided NiMo/y-Al₂O₃ and CoMo/y-Al₂O₃ catalyst. CoMo catalyst shows much lower catalytic activity than NiMo catalyst at low opearting temperature (<360 °C) and become comparable to NiMo catalyst at higher temperature. However, NiMo catalyst generally gives higher selectivity of diesel range hydrocarbon therefore higher diesel yield. Under the defined operating condition, conversion (of triglyceride and fatty acid) could be in order of RPS hard > RPS soft > DPO which indicating that higher degree of saturation of feedstock lead to obtain higher conversion. Maximum of diesel range hydrocarbon yield of 71% could be obtained from RPS hard at reaction temperature of 360 °C for 4 h with sulfided NiMo/y-Al₂O₃ catalyst.