Preparation Of Jet Fuel Range Hydrocarbons By Catalytic Transformation Of Bio-oil

The growing demand of commercial jet fuels, in combination with increasing consumption of fossil fuels and the strict environmental legislations has led to immense interest in developing aviation biofuels thus becoming one of the hot research topics in the field of energy chemical industry. This work demonstrated that the bio-oil derived from fast pyrolysis of straw stalk was able to be converted into the jet and diesel fuel range hydrocarbons by a designed transformation route. The process and mechanism of the directional synthetic C8-C15aromatics and C8-C15cyclic alkanes are further researched. The results are as follows:1. The catalytic cracking of bio-oil into low-carbon aromatics and light olefinsBio-oil, is a black brown organic which consists primarily of oxygenated organic compounds. Taking into account that the bio-oil has a high oxygen content, it is very necessary to remove oxygen from the oxygenated compounds of bio-oil for the production of liquid hydrocarbon fuels. The process and mechanism of the catalytic cracking of bio-oil over the selected HZSM-5(25) into low-carbon aromatics and light olefins are researched. As a result, the aromatic hydrocarbons derived from the catalytic cracking of bio-oil reached a maximum value of29.2C-mol%and light olefins (mainlyC2=-C4=) had a yield of17.4C-mol%at optimized conditions(T=550℃, WHSV=0.5h-1.The distribution of aromatics reached97.4%. The catalyst stability during the catalytic cracking of bio-oil over the HZSM-5catalyst was tested at optimized reaction. The activity decay observed during the catalytic cracking of bio-oil could be attributed to coke deactivation together with irreversible deactivation like the dealuminization of the zeolite. The activity of the used catalysts was almost recovered by treating the used catalyst with oxygen.2. The synthesis of C8-C15aromatic hydrocarbons by the alkylation of low-carbon aromatics with light olefinsTypically, the commercial and military jet fuels are a mixture of three main components of iso/normal alkanes, cyclic alkanes and aromatic hydrocarbons ranging from C8to C15.Thus the extension of the carbon chain is necessary. The process and mechanism of the synthesis of C8-C15aromatic hydrocarbons by the alkylation of low-carbon aromatics with light olefins which derived from bio-oil using the [bmim]Cl-2AlCl3ionic liquid were researched. The distribution of C8-C15aromatic hydrocarbons can be adjusted by changing reaction temperature and time.The resulting bio-fuels after the alkylation of low carbon aromatics under the optimal reaction of80℃for3h contains71.8wt%C8-C15aromatic hydrocarbons with a high selectivity85.4%. The synthetic C8-C15aromatic biofuels basically met the main technical specifications of jet fuels. The catalyst stability of ionic liquid is tested. No significant changes in the catalytic activity of the ionic liquid [bmim]Cl-2AlCl3was found after undergoing the alkylation reactions of aromatics for18h at optimized conditions. This indicated the stability of ionic liquid is good.3.The production of C8-C15cyclic alkanes by the hydrogenation of C8-C15aromatics.The production of the C8-C15cyclic alkanes using bio-oil was conducted by the hydrogenation of the C8-C15aromatics. Nearly all of the bio-oil-derived aromatics were converted into the saturated cyclic alkanes after the hydrogenation over the Pd/AC catalyst at210℃and5PM for6h. Moreover, no significant change in the carbon number distribution of C8-C15cyclic alkanes was found as compared with the carbon number distribution of C8-C15aromatic hydrocarbons. The synthetic C8-C15cyclic alkanes biofuels basically met the main technical specifications of jet fuels.