Jet fuel-range hydrocarbons generation from the pyrolysis of saw dust over Fe and Mo-loaded HZSM-5(38) catalysts

Abstract

In this research, we studied the catalytic pyrolysis of sawdust over monometal (1 wt% Fe or 1 wt%Mo) and bimetal (1 wt% Fe-1 wt% Mo or 0.5 wt% Fe-0.5 wt% Mo)-loaded HZSM-5(38) catalysts, synthesized via wet impregnation method, for the generation of jet fuel-range hydrocarbons. In particular, we aimed to generate jet fuel-range aromatic hydrocarbons (C8-C12) and a high amount of organic-phase bio-oil at the same time from this pyrolysis. In addition, the bimetal-loaded HZSM-5(38) catalysts (1 wt% Fe-1 wt% Mo/HZSM-5(38) and 0.5 wt% Fe-0.5 wt% Mo/HZSM-5(38)) helped achieve a higher organic phase bio-oil yield (20.74 and 17.14 wt%) compared to those under the pristine HZSM-5 (9.57 wt%) and monometal-loaded HZSM-5(38) catalysts (1 wt%Fe/HZSM-5(38) and 1 wt% Mo/HZSM-5(38)) (13.04 and 11.45 wt%, respectively). The exchange of the strong Brønsted acidity in the HZSM-5(38) support with an added metal (Mo and Fe) ion of this catalyst might have prevented excessive cracking and dehydration of the bio-oil intermediates, thereby increasing the organic-phase bio-oil yield of the pyrolysis. The coke amount of bimetal-loaded HZSM-5(38) catalyst was lower than that of monometal-loaded HZSM-5(38). Overall, the bimetal-loaded HZSM-5(38) catalysts possessed a synergistic effect leading to their high activity, generating the higher amount of jet fuel-range hydrocarbons because of the enhanced deoxygenation such as hydrodeoxygenation and dehydrogenation reactions of the pyrolysis under this catalyst.