INTEGRATED HYDROPROCESSING SCHEME FOR PRODUCTION OF PREMIUM QUALITY DISTILLATES AND LUBRICANTS

摘要

AbstractAn integrated refining scheme is disclosed forhydroprocessing high boiling fractions such as gas oil andcatalytically cracked cycle oils to produce premium qualitydistillates, especially jet fuels and naphthas suitable forreforming into high octane gasoline. The integrated hydroprocessingcomprises a first stage hydrocracking step employing an aromaticselective hydrocracking catalyst based on a large pore size acidiccomponent such as amorphous alumina or silica alumina or a largepore size zeolite such as zeolite X or zeolite Y. The hydrocrackingmay be operated either in a naphtha directing mode under conditionsof moderate to high severity or under conditions of low to moderateseverity to produce a relatively higher proportion of productboiling in the middle distillate range. The unconverted fractionfrom the hydrocracking step is passed to a second step in which itis hydroprocessed over a zeolite beta catalyst with additionalhydrogenation-dehydrogenation functionality. In this stage, theparaffins remaining in the feed are converted by the zeolite betainto isoparaffins and conditions may be controlled to favorhydroisomerization over hydrocracking so as to increase the yield ofmiddle distillate product, especially of highly isoparaffinic jetfuels and diesel fuel.