Coproduction of Value-Added Lube Base Oil and Green Diesel from Natural Triglycerides via a Simple Two-Step Process

Abstract

A versatile process for coproducing green diesel and value-added lube base oil from natural triglycerides (e.g., vegetable oil, waste cooking oil, and microalgal oil) was developed. The twostep reaction process comprises (i) thermal oligomerization of triglycerides via Diels−Alder and/or radical-mediated addition of the CC bonds within the fatty acid units and (ii) catalytic deoxygenation of the oligomerized triglycerides via hydroupgrading. Different triglyceride sources, that is, palm oil, soybean oil, and linseed oil, were investigated as the starting feedstock. Thermal oligomerization of the triglycerides at 300 °C proceeded at the expense of the CC bonds within the unsaturated fatty acid units. Thus, the degree of triglyceride oligomerization was enhanced when the reactant triglycerides contained more unsaturated fatty acid units (palm oil < soybean oil < soybean + linseed oil < linseed oil). The oligomerized triglycerides were subsequently deoxygenated over a Pt-MoO x /TiO 2 catalyst, which converted the oligomerized and monomeric fatty acid units into lube base oil (C 30 −C 54 ) and green diesel (C 15 −C 18 ) fractions, respectively. The produced lube base oils were completely saturated with very high viscosity indexes (>120) and a nondetectable sulfur content, which could meet the specifications of high-quality group III lube base oil.

Production of Biofuels from Hydrodeoxygenation and Hydroisomerization of Triglycerides with Metal-Supported SAPO-11 Molecular Sieves

“…Several intermediate oxygenates and alkenes are obtained during the reaction, and oligomerization and rearrangement of such intermediates might provoke the formation of aromatics, heavy polymers, and coke. Regarding oligomerization of free fatty acids, if the unsaturated double bonds are not saturated, they may undergo oligomerization through Diels–Alder condensation to yield cyclic fatty acid units, comprising even C 30 –C 70 hydrocarbons . Hence, the relatively high content of the 365 °C + fraction can be explained by the occurrence of thermal transformations and oligomerization pathways competing with the desired HDO and isomerization routes .…”

“…Regarding oligomerization of free fatty acids, if the unsaturated double bonds are not saturated, they may undergo oligomerization through Diels−Alder condensation to yield cyclic fatty acid units, comprising even C 30 −C 70 hydrocarbons. 52 Hence, the relatively high content of the 365 °C + fraction can be explained by the occurrence of thermal transformations and oligomerization pathways competing with the desired HDO and isomerization routes. 53 This oligomerization and Diels−Alder reactions inhibit catalyst activity due to coke formation and suggest that the efficiency of the hydrogenation of the double bonds is lower than expected.…”

Catalytic deoxygenation of palm oil over metal phosphides supported on palm fiber waste derived activated biochar for producing green diesel fuel

“…9 Currently, catalytic deoxygenation for upgrading biomass feedstocks into green fuels was run over porous materials supported noble metals (e.g., palladium, platinum, and rhodium) catalysts, which is regularly employed as a commercial benchmark catalyst. [10][11][12] However, the utilization of noble metals is less economically attractive than transition metal-based catalysts: nickel, cobalt, iron, molybdenum in commercialization scale. Furthermore, supported noble metal catalysts in metallic form show the poor stability in long-term catalytic run that should be urgently encountered.…”

Catalytic deoxygenation of fatty acidsviaketonization and α-carbon scissions over layered alkali titanate catalysts under N2

“…[5][6][7][8] A selective and efficient fatty acid transformation can potentially contribute to energy security, economic gain, and global warming mitigation. This is better achieved via a cascade reaction 9,10 in which one reaction occurs aer another in a controlled manner, allowing chemical syntheses in a single step without extensive work up or products separation.…”