title: Low-temperature, selective catalytic deoxygenation of vegetable oil in supercritical fluid media.
abstract: The effects of supercritical fluids on the production of renewable diesel-range hydrocarbons from natural triglycerides were investigated. Various supercritical fluids, which included CO2 (scCO2 ), propane (scC3 H8 ) and n-hexane (scC6 H14 ), were introduced with H2 and soybean oil into a fixed-bed reactor that contained pre-activated CoMo/γ-Al2 O3 . Among these supercritical fluids, scC3 H8 and scC6 H14 efficiently allowed the reduction of the reaction temperature by as much as 50 °C as a result of facilitated heat and mass transfer and afforded similar yields to reactions in the absence of supercritical fluids. The compositional analyses of the gas and liquid products indicated that the addition of scC3 H8 during the hydrotreatment of soybean oil promoted specific deoxygenation pathways, decarbonylation and decarboxylation, which consumed less H2 than the hydrodeoxygenation pathway. As a result, the quantity of H2 required to obtain a high yield of diesel-range hydrocarbons could be reduced to 57 % if scC3 H8 was used. As decarboxylation and decarbonylation are mildly endothermic reactions, the reduced heat transfer resistance in scC3 H8 may drive the deoxygenation reaction to thermodynamically favourable pathways.
authors: Clean Energy Research Center, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Republic of Korea).
authors: Seok Ki
authors: SK
authors: Kim
authors: Hong-Shik
authors: HS
authors: Lee
authors: Moon Hyun
authors: MH
authors: Hong
authors: Jong Sung
authors: JS
authors: Lim
authors: Jaehoon
authors: J
authors: Kim
mesh_terms: D002384:Catalysis; D006859:Hydrogen / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry*; D044367:Phase Transition; D010938:Plant Oils / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry; D013696:Temperature
chemical_list: D010938:Plant Oils; D012997:Solvents; D006859:Hydrogen; D010100:Oxygen
keywords: biomass; fatty acids; hydrocarbons; hydrogen; supercritical fluids