Hydrodeoxygenation of vegetable oil over the Pt/WOx-Al2O3 catalyst

Abstract

The paper is devoted to the effect of chemical composition of the support on acidity and dispersion of supported platinum for 0.5 % Pt/WOx-Al2O3 catalysts as well as their activity and selectivity in hydrodeoxygenation of sunflower oil. It was found that an increase in the content of tungsten in the support is accompanied by an increase in the number of Broensted acid sites on its surface and a decrease in the dispersion of supported platinum in the final catalyst. The activity of 0.5 % Pt/WOx-Al2O3 catalysts does not depend on the composition of support and ensures complete conversion of sunflower oil in a hydrogen atmosphere at a mass flow rate of liquid raw material 1 h–1, temperature 380 °C and total pressure 4 MPa. Therewith, nearly a stoichiometric yield of liquid products С5+ at a level of 82–86 wt.% is achieved. Acidic properties of the 0.5 % Pt/WOx-Al2O3 system determine the possibility of obtaining the hydrocarbon components of diesel fuels with a high content of isoalkanes as a result of hydrodeoxygenation of sunflower oil. The use of the catalyst with the nominal content of tungsten 15 wt.% WO3 leads to the fraction of monomethylsubstituted isomers in the sum of octadecanes at a level of up to 74 % with the complete conversion of the initial feedstock retained during 24 hours.