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Although hydrodeoxygenation (HDO) is proven a promising process for upgrading pyrolysis bio-oil to hydrocarbon biofuel, catalyst efficiency remains a challenge. Integrating heterogeneous catalysts with supercritical liquid in a bio-oil HDO process was investigated in this study. Bifunctional Fe-Ni/HZSM-5 catalysts were firstly used to upgrade bio-oil to hydrocarbon biofuel in supercritical methanol. The loading of Fe and Ni did not change HZSM-5 crystalline structure, but BET surface area and total pore volume of Fe-Ni/HZSM-5 catalysts decreased significantly compared to HZSM-5 support. Physicochemical properties of biofuel produced by Fe and/or Ni loaded HZSM-5 catalysts such as water content, total acid number, viscosity and higher heating value improved in comparison with raw bio-oil. Bimetallic Fe-Ni/HZSM-5 catalysts were more effective for bio-oil HDO compared to monometallic Fe/HZSM-5 or Ni/HZSM-5 catalyst , and this was attributed to the synergistic effect of Fe and Ni on HZSM-5 support. Fe-Ni(2)/HZSM-5 catalyst produced biofuel with the highest hydrocarbon content at 28.60%. [ABSTRACT FROM AUTHOR]

Upgraded bio-oil can partly replace fossil fuels to reduce the environmental issues caused by the massive consumption of fossil fuels. Hydrodeoxygenation is a promising route for upgraded bio-oil production from pyrolysis bio-oil. Non-sulfide catalysts are effective in bio-oil hydrodeoxygenation due to low cost and high activity. Ni-Zn/Al 2 O 3 catalysts were first used to selectively produce hydrocarbon upgraded bio-oil through bio-oil hydrodeoxygenation. Upgrading pine sawdust bio-oil to upgraded hydrocarbon bio-oil was performed using a series of Ni and/or Zn loaded Al 2 O 3 catalysts. The crystalline structure of Al 2 O 3 was maintained after Ni and/or Zn loading, but BET surface area and total pore volume of Ni-Zn/Al 2 O 3 catalysts decreased significantly compared to Al 2 O 3 support. Bimetallic Ni-Zn/Al 2 O 3 catalysts were more effective than monometallic Ni/Al 2 O 3 or Zn/Al 2 O 3 catalyst . Bimetallic 15%Ni-5%Zn/Al 2 O 3 catalyst generated the highest upgraded bio-oil yield at 44.64 wt% and produced the upgraded bio-oil with the highest hydrocarbon content at 50.12%. Physicochemical properties of upgraded bio-oils including heating value, water content and pH were significantly improved in comparison with raw bio-oil. The improved catalytic performance of bimetallic Ni-Zn/Al 2 O 3 catalyst was associated with the synergistic effect of Ni and Zn on Al 2 O 3 support. [ABSTRACT FROM AUTHOR]

Cracking of camelina oil over non-catalyst and ZSM-5 catalyst doped with different Zn concentrations (0, 10, 20 and 30 wt.%) in a fixed-bed reactor was investigated. The fresh and used catalysts were characterized using XRD, FT-IR, BET and TEM. Characterizations of the produced hydrocarbon biofuel, distillation residual and non-condensable gas were carried out. The effect of non-catalyst and catalyst on the physicochemical properties and yield of products was discussed. The results showed that the introduction of Zn did not change the zeolite crystalline structure and ZnO might deposit on the external surface and/or inside the pores of the support ZSM-5. After upgrading, hydrocarbon biofuel had a lower viscosity, lower density, higher heating value (HHV) and higher water content than raw camelina oil. The optimum Zn concentration to ZSM-5 was 20 wt.%, at which the highest hydrocarbon biofuel yield and comprehensively the best quality were obtained. Compared to non-catalytic cracking of camelina oil, the loading of Zn to ZSM-5 could improve some physicochemical properties of the hydrocarbon biofuel. In addition, the loading of Zn to ZSM-5 could facilitate the chemical reactions such as decarbonylation and dehydrogenation. [ABSTRACT FROM AUTHOR]