Pyrolytic-deoxygenation of triglycerides model compound and non-edible oil to hydrocarbons over SiO2-Al2O3 supported NiO-CaO catalysts

Catalytic deoxygenation (DO) of triglycerides-based feeds to diesel-like fuel was investigated over NiO-CaO/SiO2-Al2O3 and NiO/SiO2-Al2O3 catalysts using semi-batch reactor under partial vacuum and inert N-2 flow. The results showed that the bi-functional catalyst exhibited the highest DO activity with product selectivity toward diesel-like fuel n-(C-13-C-20). The catalytic process appeared to inhibit the occurrence of side reactions via neutralization of the strong acid sites. On the other hand, DO reaction under inert N-2 flow has improved the deoxygenated product, which demonstrate that N-2 flow condition has effectively removed the decarboxylation/decarbonylation gasses (CO2/CO) from poisoning the catalyst active sites. The high concentration of strong basic-acid sites of the catalyst is the main reason for increased C-C cleavage pathway, while milder acidic sites responsible for C-O cleavage pathway. High degree of unsaturated fatty acid in the feedstock has affected adversely the DO of triglycerides by accelerating the catalyst deactivation. The N-2 flow condition, degree of unsaturated fatty acid in the feedstocks, acidity and basicity of the catalysts are important factors to improve DO activity as well as product selectivity.