Study On Hydrodeoxygenation Of Biomass Oil By Bimetallic Catalysts

With the development of society,the demand for energy is increasing.The consumption of fossil energy and deteriorating environmental problems prompt human beings to develop and utilize renewable energy.Facing the energy crisis and climate change,biofuel is a better way out.The production of first category biofuels through transesterification has been commercialized.This kind of biodiesel（fatty acid methyl ester）has high oxygen content,low calorific value,high acidity and poor stability.Another point is that it is not satisfactory to compete with food.For second category biofuels,non-edible jatropha oil can be used to produce biofuels,including green diesel and jet fuel.More and more researchers are committed to upgrading biomass-derived bio-oils to more stable and higher-quality biofuels through possible ways of hydrodeoxygenation,including direct hydrodeoxygenation,decarboxylation and/or decarbonylation.A novel multifunctional Ni-Fe/SAPO-11 catalysts were synthesized,characterized and their activity was evaluated for the solvent-free hydrodeoxygenation of jatropha oil.The catalyst has a spherical structure and moderate acid strength,and exhibited excellent cyclization and deoxidation activity.The presence of Fe promotes the dispersion of active components,the iron-nickel alloy particle size was small,and gives an optimal distribution of product.The composition of the products is linear alkanes（59.83%）,isoparaffins（4.16%）,aromatics（8.41%）,and naphthenes（12.03%）,where jet fuel components are relatively high,accounting for 55.04%of C8-C16 hydrocarbons.The presence of iron in the catalyst let to use an external magnetic field to quickly separate and recycle the catalyst.The recycled catalyst still maintain a high activity after 5 cycles:the hydrocarbon content was more than 85%.The synergic effect of the metallic and acidic sites of the catalyst,let to realize one pot hydrodeoxygenation,isomerization,aromatization and cracking of substrate forming bio-jet fuel hydrocarbons.Although nickel-molybdenum bimetal has been used to convert biomass into biofuels,the effect of Ni Mo P phase on the deoxygenation pathway of jatropha oil is unclear.From the perspective of carbon atom economy,preferential direct deoxygenation to alkanes is of interest.Therefore,a series of catalysts with nickel molybdenum phosphide supported on SAPO-11,ZSM-5 and Zr-SBA-15 were prepared,and they were used to hydrodeoxidize jatropha oil in an autoclave.The effects of different carriers and n（Ni-Mo）/n（P）on the hydrodeoxygenation pathways were studied.Different supports affect the formation of the active phase of nickel molybdenum phosphide and its acid sites,and together affect the catalytic performance,resulting in different deoxidation pathways.For different n（Ni-Mo）/n（P）catalysts on the same carrier,the deoxygenation pathways are also different.In addition,Ni Mo P phase has high hydrodeoxygenation activity with a deoxygenation of over 90%,and the addition of P promotes direct deoxygenation and inhibits decarboxylation and decarbonylation.The product oil contains high jet fuel components,C8-C16 alkanes accounting for more than 50%of the product oil.Ni Mo P phase also plays an important role in inhibiting coke deposition.Using water as the solvent,Raney Ni and IL/Zr-SBA-15 composite catalysts were used to conduct hydrodeoxygenation of coconut clothes pyrolysis oil by tandem reactions.The imidazole-based Br（?）nsted acidic ionic liquid（IL）was synthesized and loaded on Zr-SBA-15 n（Si）/n（Zr）=10 to obtain a new type of catalyst IL/Zr-SBA-15.The structure of the catalyst was characterized by XRD,FTIR,SEM,TEM,N₂adsorption-desorption and DSC/TG,indicating that IL has been successfully immobilized on the surface of Zr-SBA-15.Even in the chemical grafting reaction,the ordered mesoporous structure can also be well retained.The process conditions were optimized by the response surface method.In addition,it can be concluded that the reaction conditions affected the order of the content of naphthenic components as the reaction temperature>reaction time>hydrogen pressure.The results of catalyst recovery showed that after five consecutive operations,the conversion of phenol was almost unchanged,and the selectivity of cyclohexane decreased slightly.As a result,the content of naphthenic components in the pyrolysis oil reached 34.43%,and the HHV was 37.58 MJ/kg,indicating that the catalyst is effective for pyrolysis oil.The hydrocarbons in the product oil can be used as jet fuel components.