The catalytic deoxygenation reaction temperature and N2 gas flow rate influence the conversion of soybean fatty acids into Green Diesel

• At high temperatures, reactive intermediates radicals generated will react with molecular oxygen present forming additional oxygenated compounds. • The increasing nitrogen flow rate could reduce the contact time between oil and the catalyst, which can affect the selectivity and yield of hydrocarbon. • The effect of reaction temperature and nitrogen flow rate significantly affected the deoxygenation activity. • NiO CD catalyst has the potential to lower the overall cost of producing green diesel by evaluating the life cycle cost analysis (LCCA) of stepwise catalyst preparation and green diesel production. Green diesel is a promising alternative as a petroleum replacement given the worldwide demand for petroleum fuel. Environmental issues have drawn public attention and concerns towards advancing renewable energy development. A catalytic deoxygenation (deCOx) was carried out to produce green diesel from soybean oil (SO) using a low-cost NiO-doped calcined dolomite (NiO CD) catalyst. The structure, chemical composition and morphology of NiO CD were comprehensively characterized by XRF, BET, TPD-CO 2 , SEM and TEM. In this study, the effect of two operating parameters, reaction temperature and flow rate of nitrogen, was discovered using a one-factor-at-a-time (OFAT) optimisation study. In addition, the life cycle cost analysis (LCCA) of stepwise catalyst preparation and green diesel production has been performed. An optimal reaction temperature of 420 °C was found to provide the highest yield of green diesel (47.13 wt.%) with an 83.51% hydrocarbon composition. The ideal nitrogen flow rate, however, was found to be 50 cm 3 /min, which produced 41.80 wt.% of green diesel with an 88.63% hydrocarbon composition. The deoxygenation reaction was significantly impacted by both reaction temperature and nitrogen flow rate. According to LCCA, NiO CD catalyst has potential to lower the overall cost of producing green diesel compared to commercial zeolite catalysts.