GB1331778A - Hydrogenation of residual petroleum fractions - Google Patents

Abstract

1331778 Hydrocracking HYDROCARBON RESEARCH Inc 13 Aug 1970 39130/70 Heading C5E A reduced crude of which at least 25% boils above 975‹ F. is hydrogenated by (a) passing it with hydrogen-rich gas at elevated temperature and pressure upwards through a bed of hydrogenation catalyst having a size range between 4 and 325 mesh (U.S.S.) at a velocity high enough to expand the catalyst bed by at least 10% and maintain the catalyst in random motion and at a space velocity such that more than 50% conversion of components boiling above 975‹ F. to products boiling below 975‹ F. is obtained, (b) separating the product into gaseous and liquid fractions, of which one liquid fraction is rich in material boiling above 900‹ F. and contains substantially all of the asphaltenes and condensed polycyclic aromatics of the feed, (c) removing the asphaltenes and condensed polycyclic aromatics from this fraction, and (d) recycling this purified fraction at a rate equivalent to between 1 and 25% of the feed. As shown, the residuum 10 is fed with hydrogen from line 16 to reactor 18. Catalyst may be added, as slurry, at 12 or at 48 and is drawn off at 50. The bed of catalyst terminates at an interface 22, and oil from the zone above this interface is recycled by a pump 21 through a conduit 51. Vapour from the space 23 is separated at 28 into gas, mainly hydrogen, which is purified and recycled, and a liquid which is fractionated at 36. Liquid from the reactor is drawn off at trap tray 43 and fractionated at 60. The bottoms from this fractionation are further fractionated under vacuum at 66, and a bottoms product drawn off comprising material boiling above 900‹ F. This material is purified at 71, either by a further vacuum distillation, or by solvent extraction, and recycled. Alternatively, the recycle fraction may be a side stream from the fractionator 66. The hydrogenation may be carried out in two or more zones, the effluent from each zone but the last being passed to the next, and the purification being carried out on the effluent from the last hydrogenation zone.