Gulf Research & Development Company

James A Frayer

John A Paraskos

Stephen J Yanik

Joel D McKinney

Harry C Stauffer

Richard E Hildebrand

Henri K Lese

Kirk J Metzger

Angelo A Montagna

Francis Edmund Wynne, Jr

Kirk J Metzer

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.+ (566.degree. C.+) residual components in the cracking feedstock is diminished whereby the amount of 1050.degree. F.+ (566.degree. C.+) residuals vaporized per barrel of feedstock during the subsequent cracking step is increased. The present method provides an interdependent advantage in the hydrodesulfurization operation since it reduces hydrogen consumption during hydrodesulfurization.

Combination residual oil hydrodesulfurization and catalytic cracking

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. Modifying the aliquot distribution of distillate and residual components in this manner provides an interdependent effect in the combination process since the distillate-enriched cracking feedstock not only provides both an improved ethylene yield and a greater steam economy in the thermal cracking operation but it also reduces hydrogen consumption in the hydrodesulfurization operation. Further interdependence between the hydrodesulfurization and thermal cracking operations is obtained by utilizing the residual oil which is selectively removed during the hydrodesulfurization step as fuel in the solids regenerator of the cracking unit, thereby making the more valuable, highly aromatic black oil produced in the thermal cracking process available for conversion to needle coke and carbon black.

Combination residual oil hydrodesulfurization and thermal cracking

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. A portion of the intermediate stage effluent stream is split out of the process as product fuel oil and the remaining portion of the intermediate stage effluent stream is passed to a downstream hydrodesulfurization stage together with the light distillate feed fraction and hydrogen. The downstream stage effluent stream constitutes the final and highest grade product of the process. Because of the combination of segmented feed addition and segmented product removal, not only are residue-containing streams removed from the process at the earliest possible time to avoid overtreating relative to their intended use, but also the removed streams are diluted with a reduced amount of low boiling distillate oil, conserving as much of the low boiling distillate oil as possible for inclusion in the product of the final stage. This method conserves distillate feed oil for the final and highest grade product and allows each hydrodesulfurization stage to be provided with a non-aliquot distillate-residual oil stream which is richer in low boiling distillate oil than its predecessor hydrodesulfurization stage.

Multistage residual oil hydrodesulfurization process employing segmented

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. The interstage diminution of the residual oil fraction provides a non-aliquot distillate-residual oil second stage feed stream which is relatively enriched in distillate oil. Since the sulfur in distillate oil is considerably less refractory than the sulfur in residual oil, the resulting dilution of the residual content of the downstream stage feed stream reduces hydrogen consumption by diminishing the depth of residual oil hydrodesulfurization required in the downstream stage to produce a low sulfur product.

Multistage residual oil hydrodesulfurization process

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. Since the sulfur in distillate oil is less refractory than the sulfur in residual oil, removal of a portion of the concentrated residual oil fraction provides a nonaliquot distillate-residual oil downstream stage feed stream which is easier to desulfurize to a low sulfur level than an aliquot distillate-residual oil stream. The dilution of the high sulfur residue in the downstream stage diminishes the depth of hydrodesulfurization required for residual components in the downstream stage, thereby reducing the level of hydrogen consumption required to produce a product having a low sulfur level.

Multistage residual oil hydrodesulfurization process with an interstage

A catalyst having utility as a downstream catalyst in processes for hydrodesulfurization of asphaltene-containing petroleum oils, coal liquids, shale oils or oils from tar sands which employ both upstream and downstream catalysts in series. The downstream catalyst comprises supported Group VI and Group VIII metals together with a promoting amount of a Group IV-B metal. The particles of said promoted catalyst are elongated extrudates whose surface is provided with a plurality of alternating longitudinal grooves and protrusions. In processes using this catalyst, the upstream catalyst comprises Group VI and Group VIII metals without promotion with Group IV-B metal and the particles of the upstream catalyst may or may not have similar surface grooves. The adaptation of the grooved particle configuration to the promoted catalyst composition provided the early development of a plateau-like aging curve which was not achieved by the adaptation of the grooved shape to a non-promoted catalyst.

Hydrodesulfurization catalyst

An asphaltene-containing oil hydrodesulfurization process employing a guard reactor and a main reactor in series, with the diameter of the guard reactor being smaller than the diameter of the main reactor. The catalyst in the guard reactor comprises particles of supported Group VI and Group VIII metals in the form of elongated extrudates whose surface is provided with a plurality of alternating longitudinal grooves and protrusions. An advantageous mass velocity-related activity effect is demonstrated when catalyst particles having this shape are disposed in a guard reactor having a smaller diameter than the diameter of the main reactor with which it is associated.

Hydrodesulfurization process employing a guard reactor

An asphaltene-containing oil hydrodesulfurization process employing an upstream catalyst and a downstream catalyst in series. The downstream catalyst comprises supported Group VI and Group VIII metals together with a promoting amount of Group IV-B metal in the form of particles whose surface is shaped by multiple elongated alternating grooves and protrusions. The upstream catalyst comprises Group VI and Group VIII metals without promotion with Group IV-B metal in the form of particles which may or may not be similarly shaped. Beds of the downstream and upstream catalyst may be diposed in the same or in different reactors. The adaptation of the grooved particle configuration to the promoted catalyst composition provided the early development of a plateau-like aging curve which was not achieved by the adaptation of the grooved shape to a non-promoted catalyst.

Hydrodesulfurization process employing a promoted catalyst

A catalytic asphaltene-containing oil hydrodesulfurization process employing a fixed catalyst bed comprising particles of supported Group VI and Group VIII metals, preferably together with a separate and downstream fixed catalyst bed comprising particles of Group VI and Group VIII metals together with a promoting amount of Group IV-B metal. The catalyst particles in both beds are in the form of elongated extrudates whose surface is provided with a plurality of alternating longitudinal grooves and protrusions. An advantageous mass velocity-related catalyst activity effect is achieved by recycling a portion of the desulfurized liquid product.

Hydrodesulfurization process including product recycle

An asphaltene-containing oil hydrodesulfurization process employing upstream and downstream reactors in series with an interstage flashing step. The catalyst in the downstream reactor comprises supported Group VI and Group VIII metals together with a promoting amount of Group IV-B metal. The particles of the catalyst in the downstream reactor are in the form of extrudates whose surface is provided with a plurality of alternating longitudinal grooves and protrusions. The catalyst in the upstream reactor comprises Group VI and Group VIII metals without promotion with Group IV-B metal and is in the form of particles whose surface may or may not have a similar grooved form. An advantageous mass velocity-related activity effect has been found when the downstream reactor has a diameter which is smaller than the diameter of the upstream reactor. The reduced diameter provides a concomitant advantage related to hydrogen pressure since it is shown that the reduced diameter permits the downstream reactor to withstand enhanced pressures and it is also shown that the promoted catalyst is particularly susceptible to regeneration via increases in hydrogen pressure.

Multi-reactor hydrodesulfurization process

An improved method for presulfiding a hydrodesulfurization catalyst which comprises continuously contacting the catalyst with a sulfiding treating agent at a relatively low temperature and pressure and only until the total amount of sulfur in the treating agent contacting the catalyst is no more than 55 percent of the amount of sulfur required to sulfide the supported metals on the catalyst to their completely sulfided forms.

Method for presulfiding hydrodesulfurization catalysts

An improved process for the hydrodesulfurization of hydrocarbons employing a catalyst comprising Group VI-B and Group VIII metals supported on a refractory oxide and promoted with a minor amount of titanium by contacting the refractory oxide with an aqueous solution of a titanium salt.

Hydrodesulfurization process employing a Group IV-B promoted catalyst

A shutdown procedure for residual hydrocarbon hydrodesulfurization process which employs a catalyst comprising Group VI-B and Group VIII metals, in sulfided form, supported on a refractory oxide and promoted with a minor amount of titanium.

Hydrodesulfurization shutdown method

An asphaltene-containing oil hydrodesulfurization process employing a downstream catalyst and an upstream catalyst in a reactor. The downstream catalyst comprises supported Group VI and Group VIII metals together with a promoting amount of Group IV-B metal. The upstream catalyst comprises Group VI and Group VIII metals without promotion with Group IV-B metal.

Desulfurization process employing multi-catalyst reactor

An asphaltene-containing oil hydrodesulfurization process employing parallel first stages in series with a unified second stage. The second stage catalyst comprises supported Group VI and Group VIII metals together with a promoting amount of Group IV-B metal. The catalyst in the first stage comprises supported Group VI and Group VIII metals without promotion with Group IV-B metal. In the process, deactivated non-promoted catalyst is replaced at least once from at least one of the parallel first stages while continuing to operate the other of the parallel first stages to supply a reduced oil flow to the second stage during the catalyst replacement step.

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Pittsburgh, PA, United States of America

James A Frayer