Destructive hydrogenation of asphaltic hydrocarbons

摘要

In a process for the production of gasoline and gas oil by the destructive hydrogenation of an asphaltic hydrocarbon oil, mixed with a diluent comprising hydrocarbons boiling in the range between 200 DEG F. and 1000 DEG F. and containing aromatic and/or naphthenic components, in the presence of a catalyst such as an oxide or sulphide of a metal of Group VI or VIII of the periodic system, the catalyst is periodically regenerated by treating it with diluent and hydrogen alone. The destructive hydrogenation and regeneration are carried out under such conditions that at least 30 per cent by volume of the diluent remains in the liquid phase, the temperature being between 725 DEG F. and 825 DEG F., and the pressure in the range from 100 to 1000 p.s.i.g. The diluent, which preferably boils between 430 DEG F. and 650 DEG F., is employed, in the on-stream periods, in a proportion between 0.5 and 3 parts of diluent per part of asphaltic oil. In the apparatus shown, asphaltic oil and diluent, supplied through lines 12 and 16 respectively, are mixed in line 15; and the mixture flows to tank 11. The mixture is pumped through line 20 wherein hydrogen is added (500 to 6000 cubic feet per barrel of feed mixture) via line 25; and then flows through the coil in furnace 7 into reactor 23 which contains a bed of cobalt molybdate supported on alumina. The reactor is maintained at a temperature of 750 DEG F. to 800 DEG F. and a pressure of 300-600 p.s.i.g.; and the space velocity of feed therein is 0.25 to 2 volumes per volume of catalyst per hour. The conversion products are discharged into separation zone 28, from which fixed gases, including hydrogen, are withdrawn through line 29, and may be recycled to line 25. The oil from zone 28 is fractionated in distillation tower 31. Light hydrocarbons leave the top of this tower, gasoline is withdrawn through line 34, heating oil is withdrawn via line 35, catalytic cracking feed is withdrawn through line 36, while heavy residue is withdrawn from the base of the tower. Any of these fractions may be recycled to line 16. When the conversion in the reactor tends to decrease, valves 14, 19 and 21 are closed and valve 39 is opened so that the diluent only passes to line 20 and thence, together with hydrogen, to the reactor. This treatment lasts 8 to 48 hours, and then the asphaltic oil is put on-stream again. After repeated regeneration of the catalyst with diluent hydrocarbons, it may become necessary to subject the catalyst to more severe regeneration treatment, e.g. treatment with oxygen-containing gas to burn off coke-like deposits.