Abstract: When residual oil is cracked to gasoline in the presence of a fluidized zeolite catalyst the oil is first catalytically hydrodesulfurized so that sulfur oxide emissions from the catalyst regenerator are held to environmentally acceptable levels. The hydrodesulfurized residual oil is flash vaporized at the elevated temperature at the inlet of the cracking riser and most of the residual oil feedstock passes into the vapor state and is cracked to valuable products. However, a portion of the 1050.degree. F.+ (566.degree. C.+) residual material cannot be flash vaporized at the riser temperature and instead deposits upon the catalyst and is coked. Data are presented which show that as the proportion of the 1050.degree. F.+ (566.degree. C.+) components in a cracking feedstock decreases, the amount of these high boiling components in each barrel of cracker feedstock which are flash vaporized can actually increase. A multistage hydrodesulfurization operation is provided in which the proportion of 1050.degree. F.

Abstract: Residual oils which are thermally cracked with entrained hot solids in a low residence time riser must be hydrodesulfurized so that sulfur oxide emissions in the flue gas of the solids regenerator are maintained within environmentally acceptable limits. Of a full range residual oil thermal cracking feedstock, the lower boiling distillate feed components are capable of providing a higher ethylene yield with a lower dispersant steam requirement as compared to the high boiling residual feed components. In accordance with the present invention, the high boiling residual components of a thermal cracker feed residual oil are selectively removed during hydrodesulfurization to provide a non-aliquot distillate-residual oil hydrodesulfurization product in which the ratio of lower boiling distillate oil to high boiling residual oil is enhanced.

Abstract: In the catalytic hydrodesulfurization of residual oil the amount of hydrogen consumed per atom of sulfur removed is relatively low until the desulfurization becomes deep, whereupon the amount of hydrogen consumed per atom of sulfur removed becomes relatively high. The present invention provides a multistage process capable of producing products of low sulfur content while avoiding deep desulfurization of the heavy portion of the residual oil so that hydrogen consumption is diminished. The feed oil is fractionated to provide a residual fraction, a heavy distillate fraction and a light distillate fraction. The residual fraction and hydrogen are charged to an upstream hydrodesulfurization stage. A portion of the upstream stage residual oil effluent stream is split out of the process for use as refinery fuel and the remaining portion of the upstream stage effluent stream is charged to an intermediate hydrodesulfurization stage together with the heavy distillate feed fraction and hydrogen.

Abstract: In the hydrodesulfurization of residual oil the amount of hydrogen consumed per atom of sulfur removed is relatively low until the desulfurization becomes deep, whereupon the amount of hydrogen consumed per atom of sulfur removed becomes relatively high. The present invention provides a multistage catalytic hydrodesulfurization process capable of producing products of low sulfur level while avoiding deep desulfurization of the heavy portion of the residual oil so that hydrogen consumption is diminished. The feed oil and hydrogen are passed through an upstream hydrodesulfurization stage and the upstream stage effluent is flashed to separate a distillate oil fraction from a concentrated residual oil fraction. A portion of the concentrated residual oil fraction is diverted from the process for use as refinery fuel and the remaining portion of the flash residue and hydrogen are charged to an upstream stage together with the flash distillate.

Abstract: In the hydrodesulfurization of residual oil the amount of hydrogen consumed per atom of sulfur removed is relatively low until the desulfurization becomes deep, whereupon the amount of hydrogen consumed per atom of sulfur removed becomes relatively high. The present invention provides a multistage hydrodesulfurization process capable of producing products of low sulfur level while avoiding deep desulfurization of the heavy portion of the residual oil so that hydrogen consumption is diminished. The feed oil is fractionated to provide distillate and residual fractions. The residual fraction and hydrogen are charged to an upstream catalytic hydrodesulfurization stage. A portion of the upstream stage effluent stream is diverted from the process for use as refinery fuel and the remaining portion of the upstream stage effluent stream is charged to a downstream catalytic stage together with the feed distillate oil and hydrogen.

Abstract: A process for the production of lubricating oils from petroleum stocks containing significant quantities of sulfur and lubricating oil components boiling above about 650.degree. F. (343.degree. C.) by subjecting such stocks to a series of steps comprising hydrodesulfurization, fractionation, and solvent extraction. The residual fraction obtained from the fractionation step may be deasphalted prior to solvent extraction.

Abstract: A process for hydrodenitrogenation of shale oil comprising fractionating the shale oil into relatively light and heavy fractions, passing the relatively light fraction through a zone containing a catalyst comprising supported molybdenum and Group VIII metal and passing the relatively heavy fraction through a zone containing a catalyst comprising supported tungsten and Group VIII metal.

Abstract: A process for hydrodenitrogenation of shale oil to convert it to a feed oil for zeolitic riser cracking comprising passing the shale oil through two catalyst stages in series, the catalyst in the first stage comprising supported molybdenum and Group VIII metal and the catalyst in the second stage comprising supported tungsten and Group VIII metal.

Abstract: A process for the production of lubricating oil in order to obtain lower viscosity lubricating oils of increased viscosity index by separating a crude lubricating oil into a residual fraction and a distillate fraction and thereafter subjecting the residual fraction to hydrotreating and separately subjecting the distillate fraction to hydrotreating under more severe conditions than employed in hydrotreating the residual fraction.