(205f) Oligomerization of Ethylene on Novel Ni-Siral Catalysts

The adverse environmental impacts of fossil fuels have expedited the development of alternative energy technologies for the production of biofuels. Jet fuel molecules, such as linear and cyclic hydrocarbons can be produced from sustainable sources with the assistance of solid heterogenous catalysts. Such catalysts promote reactions that led to high yield and selectivity of linear and cyclic hydrocarbon compounds which are constituents of jet fuel. The oligomerization of ethylene is one of the main routes for the conversion of ethylene into hydrocarbon mixtures. The present study investigates the oligomerization of ethylene for the production of liquid hydrocarbons on novel Ni-SIRAL catalysts, with 4.9 wt. % nickel loading on several SIRAL supports (SIRAL 10, SIRAL 20, SIRAL 30, SIRAL 40, SIRAL 40 HPV and SIRAL 70 HPV which have pore volumes of 0.75, 0.8, 0.9, 1.0, 1.5 and 0.9 ml/g respectively). SIRALs [x%Al₂O₃: y%SiO₂] have a comparatively high level of surface acidity and large pore volume to their microporous and mesoporous support counterparts, which minimize coking and consequently catalyst deactivation. This study compared yields and selectivity for six catalysts (Ni-SIRAL 10, Ni-SIRAL-20, Ni-SIRAL 30, Ni-SIRAL 40, Ni-SIRAL 40 HPV and Ni-SIRAL 70 HPV) for the ethylene oligomerization process, with the aim to determine the most promising SIRAL support for increased liquid yield and product selectivity to linear and cyclic hydrocarbons. The experiments were carried out in a fixed bed tubular reactor at 200⁰C and 40 bar. The maximum coke yield was 2.5 wt. % obtained with lowest pore volume catalyst (0.75 g/l), and the highest hydrocarbon liquid yield (36 wt. %) was achieved with the largest pore volume (1.5 ml/g). The liquid products obtained contain mainly C₄-C₁₀ olefins.