The Study On The Synthesis Of Bio-aviation Alkane Component From Hydrolysis Products Of Waste Oil

As China's increasing degree of external dependence on crude oil,which has seriously threatened the national energy security,it is urgent to develop clean and renewable energy.The demand for aviation fuel has surged in the past decades and the burning of traditional aviation fuel emits a large amount of greenhouse gases.By converting waste oil to bio-aviation oil can not only solve the problem of waste disposal,but also gain significant environmental and energy benefits.There are many technologies for bio-aviation fuel synthesis.Gasification Fischer-Tropsch synthesis technology has the disadvantages of high costs and large investments.Two-stage hydrogenation technology is a mature technology,but it still needs high investments.The products from high temperature cracking have poor selectivity.Compared with other technologies,decarboxylation/decarbonylation reactions can occur under simple catalytic conditions and it is not necessary to offer hydrogen during the processes,which had made it a promising and economical technology.In order to improve the efficiency of the recovery and separation process between the traditional decarboxylation catalysts and products,one kind of magnetic catalysts,which is suitable for decarboxylation of stearic acid,was developed and response surface methodology was applied to optimize the system.A series of magnetic catalysts were prepared and fatty acids were chosen as the raw materials.The performance of the catalysts was evaluated by a batch reactor.The catalysts were characterized by BET,XRD and TG.Firstly,the possible reaction pathways were proposed and the catalytic performance and reusability of magnetic catalysts were compared with that of conventional catalysts.Then,different carriers,supported metals and preparation methods of stearic acids decarboxylation catalysts were studied.Finally,the optimal catalyst was selected and the effects of single factors,such as reaction temperature,reaction time and catalyst dosage,were investigated.On this basis,the binary regression equation between the yield of target alkanes and three factors was obtained by response surface methodology.The results showed that:1.A reaction pathway of stearic acid with Pt-FeAC 300 catalysts was proposed,which mainly consisted of lots of decarboxylation reactions and accompanied by a few cracking,hydrodeoxygenation,esterification and other reactions.The performance of Ni-based catalysts was significantly improved by magnetic components than that of Pt-based catalysts.Magnetic catalysts had better catalytic performance and reusability.2.The results showed that the catalytic activity of FeAC was better than that of FeC.And it was found that 5%Pt-based catalysts showed best performance,followed by 20%Ni-based catalysts and 20%Mo-based catalysts showed the worst performance.Also,300? was the best condition for catalysts preparation.3.The optimum conditions and product yield were calculated as follows:A=2.26 h,B=302.4?,C=0.3655.And the yield is 67.27%,respectively.The analysis of the credibility of the model shows that the fitting degree of the model is good and the experimental method is relatively reliable.