Research On The Hydrogenation Of Medium And Low Temperature Coal Tar To Produce Jet Fuel And The Reaction Law

With the turbulence of international oil price and the promotion of new energy,the market interest and market demand of gasoline and diesel has changed obviously.Coal tar is also transformed from the traditional production of gasoline and diesel fuel to the production of a variety of high value-added chemical products.The key technology of coal tar hydrogenation to special jet fuel is one of the important measures to realize the comprehensive utilization of coal resources.In this paper,the process of p reparing jet fuel from medium low temperature coal tar as raw material was systematically studied,and the main achievements were as follows:1、Study on the process of hydrofining.⑴ The distillate fraction with boiling point from 200~360°C was selected as feedstock and the hydrorefine transformation law was studied on the self-made catalyst.The result shows:(1)At low temperature,the catalyst activity was low,which affected the depth of hydrogenation.When the temperature reached the peak value,the cracking reaction and dehydrogenation reaction would be aggravated with the increase of temperature,resulting in a large increase in the gasoline fraction.(2)The reaction time was longer and the hydrogenation depth was higher at low Liquid Hourly Space Velocity(LHSV).But it was easy to cause the cracking reaction due to products could not be removed in time with catalyst.(3)Under high pressure,the depth of hydrogenation,the increase of H/C atomic ratio and the content of S and N were all improved,which would improve the properties of oil products.⑵ Optimized process conditions were obtained: temperature,pressure and LHSV were 360°C、14MPa and 0.4h-1,respectively.Under this condition,the saturation degree of oil was high,up to 57.91% and the removal rates of sulfur,nitrogen and oxygen were 92.7%,91.9% and 91%,respectively.The product components contain a large amount of naphthenes similar to jet fuel and contain some tetralin,which required further hydrogenated.2、Study on hydroisomerization process.⑴ The key problem of high freezing point after refined oil was solved by hydroisomerization process and the influence of different process on the process was explored:(1)Under a low temperature,the degree of isomerization was lo w.High temperature aggravated the secondary reaction of the intermediates,resulting in lower the isomeric yield and selectivity,which was not conducive to the isomerization reaction.(2)the degree of aromatics content removal was low at low pressure and high pressure suppressed the dehydrogenation reaction,resulting in lower isomerization selectivity and poorer cold flow properties of the oil product.(3)a low LHSV could improve the quality of oil,but it would aggravate the side reaction.On the contrary,the depth of hydrogenation was too low,not only the degree of oil saturation was bad,but also was not conducive to oil conversion and selectivity.⑵ Optimized process conditions were obtained: temperature,pressure and LHSV were 380°C、10MPa and 0.8h-1,respectively.Under this condition,the yield of jet fuel was above 56.7%,which can be used as a fine harmonic base oil and the components of the products were mainly naphthenic hydrocarbons and isoalkanes by analysis.