Effect Of Additives And Support Modification On The Catalytic Performance Of MoNi/MgAl₂O₄-Al₂O₃ Catalysts For Jatropha Curcas Oil Hydrodeoxygenation

The increasing shortage of petroleum resources shortage and the deepening strict of environmental requirements under the development of the global economy,it has been considerably concerned that the study on the production of second generation of biodiesel which is environmentally friendly and a substitute for fossil fuels by means of hydrodeoxygenation of renewable animal fats and vegetable oils.The common hydrodeoxygenation supported catalysts at present have the main problems of the low catalytic hydrogenation activity and poor metal dispersion,so the development of novel hydrodeoxygenation catalysts with suitable acidity,pore structure,high activity and better dispersion of active metal becomes the most important issues in the study area of biodiesel.In this thesis,the supported Mo-Ni hydrodeoxygenation catalysts were preparated,and they were characterized by XRD?BET?Py-IR?NH₃-TPD?SEM.Using the solution of 20 wt%jatropha curcas oil+80 wt%n-octane as the feed,the hydrodeoxygenation performance of the catalysts were evaluated in a continuous flow fixed-bed reactor.The influences of the?MoO₃+NiO?/support mass ratio and the Mo/Ni moral ratio,promoter species and promoter amount,and support modification with TiO₂ and ZrO₂ on the HDO performance and properties of the catalysts were investigated.The results show that the catalyst with 25%?MoO₃+NiO?mass/support mass and Mo/Ni molar ratio 0.4 exhibited higher hydrodeoxygenation activity.The experimental results of effect of promoters on the catalytic performance of the catalysts indicate that the suitable CA addition was a 20%of CA mass/support mass,and an addition of suitable amount P could obviously reduce the aggregation of active metals and it is beneficial for the dispersions of active metals on the support and the improvement of the catalytic hydrodeoxygenation activity of the catalyst.Using ammonium dihydrogen phosphate as phosphorus source and the impregnating order of firstly P,and then MoNi,the obtained catalyst with 1%of P mass/support mass exhibited the best hydrodeoxygenation activity.The experimental results of effect of support modification on the catalytic performance of the catalysts indicate that the hydrodeoxygenation activity of the catalyst supported on the support of 15%TiO₂+85%MgAl₂O₄ or supported on the support of15%ZrO₂+85%MgAl₂O₄were all better than that of the MoNi/MgAl₂O₄.In the reaction environment,the catalysts exhibited excellent catalytic activity and hydrothermal stability during a period of 120 h on stream,and the averaged HDO of jatropha curcas oil was greater than 99.0%.The decarboxylation and decarbonylation reactions are predominant for jatropha curcas oil hydrodeoxygenation over the catalysts.At the same deoxygenation percentages,all LHSV increasing and reaction temperature decreasing are favorable to the decarboxylation and decarbonylation reaction.In addition,the amount of the active metal and additives has less effect on the reaction path of jatropha curcas oil hydrodeoxygenation over the catalysts.