Hydrodeoxygenation Of Bio-oil Over Ni And Ru Catalysts

As one of the sustainable liquid fuels,bio-oil has been widely studied in many fields.However,due to its low volatility,high viscosity,poor stability and high oxygen content greatly reduced the direct utilization of bio-oil.Further research on bio-oil is needed to remove excess oxygen to improve bio-oil its pratical value.Further catalytic hydrodeoxygenation of bio-oil is considered as one of the viable ways to convert liquid fuels and chemicals.The development of efficient catalysts has been the focus of current research on hydrodeoxygenation of bio-oil.In this paper,guaiacol and methyl laurate are chosen as model compounds to study the catalytic hydrodeoxygenation reaction process and to select the best catalyst.In this project,the catalytic effect of catalysts on hydrodeoxygenation of biomass oil were studied by using two different catalysts,nickel metal and ruthenium as active components,with molecular sieves and metal oxides as the acidic carrier reacted in the high pressure.The physical and chemical properties of the catalyst were investigated by means of physical and chemical characterization of BET,XRD and H₂-TPR.Their activity indexl was evaluated in high pressure reactor.When the reation of methyl laurate was catalysed by Ni-based catalysts supported on molecular sieve HZSM-5,the HZSM-5 carriers were treated by Na OH solution of different concentrations in order to form different hiezarchical pore structures.The hierarchical pores were found to be able to improve both the conversion of methyl laurate and the selectivity of alkanes,among which the Ni/HZSM-5-1.0 catalyst treated with 1.0 mol/L NaOH solution had the best catalytic activity with a conversion of 89.8%and the highest yield of 65.3%of undecane and dodecane.Results showed for the reaction of guaiacol on Ru-based catalyst,the catalytic effect of that supported on metal oxide was better that supported on molecular sieves.The reaction was also found to be heavily dependent on the acidity of the system.The order of catalyst conversion from guaiacol to descending order is:Ru/TiO₂>Ru/CeO₂>Ru/HY>Ru/Al₂O₃>Ru/HZSM-5>Ru/Hβ.A maximum selectivity of that catalysed by Ru/CeO₂ was 33%to phenol.Meanwhile,the catalytic effect of Ru/HZSM-5 catalyst under different pressures and temperatures was also studied in order to understand the basic mechanism of bio-oil hydrodeoxygenation.The results show that the high pressure and high temperature are beneficial condition for the formation of the aromatic compound of phenol by breaking the methoxy group,while low pressure was better for the direct hydrogenation of guaiacol.