Partial deoxygenation of pyrolysis intermediates toward fossil fuel miscible bioliquids

Abstract

Catalytic fast pyrolysis of sunflower seed shells was performed using a two-stage fixed bed reactor to produce partially deoxygenated bio-oils. Ketonization and aldol condensation reactions were performed in a dual bed reactor using a CeO2 catalyst followed by a bifunctional Cu/Ni/ZrO2 catalyst. An ethanol-saturated N2 stream was supplied to increase the H/C ratio of the pyrolysis intermediates. The oxygen content decreased from 23 to 13 wt % over the CeO2 fixed-bed due to the almost complete conversion of methoxy phenols and the formation of ketones and alkyl-substituted phenols. The Cu/Ni/ZrO2 catalyst in the presence of ethanol vapor increased the fraction of alkanes in the condensed product and favored the formation of larger ketones and higher molecular weight species. Miscibility tests showed that the partially upgraded bio-oil could be homogeneously blended with fossil fuel oil in a 1:4 mass ratio. The oily fraction of the non-catalytic pyrolysis bioliquid (oxygen content up to 23 wt %) was also partially miscible with the petroleum-derived fuel.