An inclusive experimental and kinetic understanding of the slurry phase hydroprocessing of crude oil with an active dispersed catalyst to obtain refined fuel

Abstract

The shift of the industrial focus from fuel to chemicals has urged the researchers to obtain a suitable petrochemical feedstock for the FCC unit. Currently, the slurry phase hydroprocessing is a boon for industrialists to upgrade the crude oil using dispersed catalysts. This hydroprocessed crude oil obtained from slurry phase reaction prevents the FCC catalyst unit from getting rapidly poisoned as most of the impurities is removed from the crude oil such as asphaltenes, resins, heavy metal, sulfur etc. This study puts forward the influence of reaction temperature and time on the hydroprocessing of the crude oil. First, the screening of three separate forms of unsupported trimetallic NiMoW catalysts i.e., as-synthesized (CAT1), sulfided (CAT2), and oil-soluble sulfided (CAT3) at 420 °C and 120 bar of hydrogen pressure has been performed. After screening out the best catalyst (CAT3) based on greater conversion results of heavier hydrocarbon fractions to lighter hydrocarbon fractions, further a detailed experimental study for the hydroprocessing of crude oil under hydrogen pressure (120 bar) with varying reaction temperatures (410, 420, 430 °C) and time period (3, 4 and 5 hours) has been carried. With the rise in temperature from 410 to 430 °C, although the higher conversion of heavier fractions is obtained but the increased amount in the coke weight % restricts the use of very high temperatures for slurry hydroprocessing of crude oil. At 420 °C and 120 bar H₂ pressure, CAT1 catalyst shows a reduction in heavy vacuum gas oil (>450 °C) from 20.05 wt% to 11.1 wt%, and a rise in middle distillate from 37.02 wt% to 50.4 wt%. When CAT2 catalyst is employed, a decrease in heavy VGO from 20.05 wt% to 9.3 wt% was observed with an increase in the middle distillates from 37.02 wt% to 52.1 wt%. CAT3 catalyst leads to maximum reduction in heavy VGO from 20.05 wt% to 7.1 wt% with an increase in the middle distillates from 37.02 wt% to 55.2 wt%, which shows the importance of oil-soluble catalyst to obtain better quality petro FCC feed. The kinetic study has also been performed for a better understanding of the reaction pathway. Based on the kinetic study, the activation energy associated with each hydrocarbon fraction has been determined and presented in the work. Such a detailed study covering all these valuable parameters along with kinetic study has not been presented till now which is the novelty of our work also.