Production Of Aviation Fuel By Catalytic Cracking Of Non-Edible Oil With Binary Metal Oxides

The purpose of this research is to explore the feasibility of one-step preparation of aviation fuel by catalytic cracking of Non-edible oil with composite metal oxides as catalyst support.The support was loaded with non noble metal,so that it can prepare aviation fuel by one-step catalytic hydrocracking of non-edible oil.Catalyst characterization analysis of the catalyst and the component analysis of the product were carried out to explore its catalytic reaction mechanism.This study was expected to provide a reference for the research on the directional preparation of aviation fuel by modifying other composite metal oxides as catalyst support,reduce the production cost and meet the requirements of continuous production in industry.The main contents and results of the research work are as follows:（1）A novel Nb₂O₅-ZrO₂ support was synthesized and used to support Ni or Mometal.γ-Al₂O₃ and SAPO-11 were selected as supports for comparison.The microstructure and acidity of catalyst supports,supported metals and modified catalysts were studied by X-ray diffraction（XRD）,N₂ isothermal adsorption desorption,scanning electron microscope（SEM）,transmission electron microscope（TEM）,H₂ temperature programmed reduction（H₂-TPR）,X-ray photoelectron spectroscopy（XPS）,inductively coupled plasma emission spectroscopy（ICP-OES）and NH₃ temperature programmed desorption（NH₃-TPD）.The results showed that the prepared Nb₂O₅-ZrO₂ support had high specific surface area(34.1 m²g^-1),appropriate pore size（13.7 nm）,appropriate medium strength acid center and appropriate total acid content.In the process of loading active metals on the support,the active phases Ni and MoO₂ generally exist on the surface of the catalyst,and some active metals will also exist in the pores of the catalyst to block the pores of the catalyst in the form of Ni O and MoO₃.（2）The catalysts were used for catalytic hydrodeoxidation of glycerol trioleate into jet fuel range hydrocarbons in one step.The results showed that the reduced Ni metal can significantly promote the hydrodeoxidation of glycerol trioleate and improved the selectivity of alkanes（57.1-73.0%）.For the prepared Nb₂O₅-ZrO₂ support,the high surface area(34.1 m²g^-1),suitable pore size（13.7 nm）and appropriate medium strength acidic sites with proper density made Ni/Nb₂O₅-ZrO₂ catalyst benefit for high selectivity of jet fuel（54.5%）in liquid products（68.5%）.Compared with Ni/γ-Al₂O₃ catalyst,it reduced the generation of coke and gas and increased the yield of liquid product.For Ni/SAPO-11,the hydrodeoxidation degree of Ni/Nb₂O₅-ZrO₂ was higher and inhibited the excessive production of aromatics in liquid products.The specific composition of hydrocarbons in the C8-C16 range was 65.9%alkanes,8.6%aromatics,16.1%olefins and 2.3%oxygenates,which meant that the product after catalytic cracking of Ni/Nb₂O₅-ZrO₂ almost meet the needs of jet fuel.（3）Non-edible bio-oil--microalgae oil was used as feedstock to explore the possibility of one-step preparation of aviation kerosene over Ni/Nb₂O₅-ZrO₂ and determine the optimal reaction conditions for the preparation of aviation fuel from microalgae oil by discussing the relevant reaction influencing factors.The results showed that the content of Ni metal in the hydrogenation center affected the hydrogenation performance of the catalyst and can promote the formation of more alkanes.The optimum reaction conditions for the preparation of aviation fuel by catalytic hydrocracking of microalgae oil with 20%Ni/Nb₂O₅-ZrO₂ catalyst were as follows:temperature 400°C,pressure 4 MPa H₂ and time 120 min.Under the optimum reaction conditions,the yield of the reaction was:68.43%oil,7.32%carbon deposition,24.13%gas.The hydrocarbon content of C8-C16 aviation fuel accounts for 75.3%of liquid products.The specific component distribution in the liquid product is:50.8%alkane,5.4%olefin,22.38%aromatics and 11.35%oxygenates.