Study On Hydrotreating Of Venezuelan Heavy Oil

The slurry bed hydrocraking of a Venezuelan heavy oil was performed at 420℃for 1h in a 500ml autoclave initially pressuried with 7.0MPa of hydrogen. The experiments with five types of catalysts and without catalyst were compared. The results showed that the catalysts in slurry bed hydrocracking of heavy oil played an important role in hydrogenation activity and suppressing the formation of coke. The yield of coke is in the range of 0.53% to 3.27% with the presence of catalysts and 5.7% without catalyst. Catalyst 2# which can effectively promote the activation of gaseous hydrogen, inhibit the addition reaction of free radical and olefins, suppress hydrogen transfer between the free radicals, but also can inhibit hydrogen transfer from cycloalkyl of aromatic hydrocarbon to free radicals, is a promising slurry-bed hydrogenation catalyst.The effect of catalyst 2# concentration ranging from 0 to 4000μg/g on the hydrocracking of the Venezuelan crude oil was evaluated. The experimental results showed that the optimum concentration of catalyst is 1000μg/g when the heavy oil was hydrocracked at 420℃for 1.0h under the reaction pressure of 7.0MPa.The influence of catalyst recycle on the crude oil hydrocracking was tested. The experimental results showed that when the catalyst was reused, the hydrogenation activity and inhibition of coke formation was reduced. The yield of toluene insolubles increased by 0.4% after the catalyst was cycled twice.In order to obtain the influence of reaction temperature and reaction pressure on the hydrogenation of Venezuelan crude oil, the hydrocracking activities was performed at 390~420℃and under the pressure of 6.0~10MPa. The data showed that the rising temperature would promote the cracking reaction and condensation reaction of free radicals, and increase the fractions with boiling point below 360℃and coke yield; The amount of active hydrogen increased with reaction pressure, which is conducive to the extinguishment of free radicals generated by thermal cracking, while promoting the hydrogen cracking reaction of molecule below 360℃fractions.