Catalyst – solid sorbent – or support therefor: product or process – Process applicable either to preparing or to regenerating or...
Reexamination Certificate
2001-10-12
2004-10-12
Griffin, Walter D. (Department: 1764)
Catalyst, solid sorbent, or support therefor: product or process
Process applicable either to preparing or to regenerating or...
C208S244000, C208S20800M, C208S247000, C208S299000, C208S307000, C208S217000, C502S406000, C502S407000, C502S415000
Reexamination Certificate
active
06803343
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a sorbent composition, a process of making a sorbent composition, and a process of using a sorbent composition for the removal of sulfur from a hydrocarbon-containing fluid.
Hydrocarbon-containing fluids such as gasoline and diesel fuels typically contain a quantity of sulfur. High levels of sulfur in such automotive fuels is undesirable because oxides of sulfur present in automotive exhaust may irreversibly poison noble metal catalysts employed in automobile catalytic converters. Emissions from such poisoned catalytic converters may contain high levels of non-combusted hydrocarbons, oxides of nitrogen, and/or carbon monoxide, which, when catalyzed by sunlight, form ground level ozone, more commonly referred to as smog.
Much of the sulfur present in the final blend of most gasolines originates from a gasoline blending component commonly known as “cracked-gasoline.” Thus, reduction of sulfur levels in cracked-gasoline will inherently serve to reduce sulfur levels in most gasolines, such as, automobile gasolines, racing gasolines, aviation gasolines, boat gasolines, and the like.
Many conventional processes exist for removing sulfur from cracked-gasoline. However, most conventional sulfur removal processes, such as hydrodesulfurization, tend to saturate olefins and aromatics in the cracked-gasoline and thereby reduce its octane number (both research and motor octane number). Thus, there is a need for a process wherein desulfurization of cracked-gasoline is achieved while the octane number is maintained.
In addition to the need for removing sulfur from cracked-gasoline, there is also a need to reduce the sulfur content in diesel fuel. In removing sulfur from diesel fuel by hydrodesulfurization, the cetane is improved but there is a large cost in hydrogen consumption. Such hydrogen is consumed by both hydrodesulfurization and aromatic hydrogenation reactions. Thus, there is a need for a process wherein desulfurization is achieved without a significant consumption of hydrogen so as to provide a more economical process for the desulfurization of hydrocarbon-containing fluids.
SUMMARY OF THE INVENTION
It is thus an object of the present invention to provide a novel sorbent system for the removal of sulfur from hydrocarbon-containing fluid streams such as cracked-gasoline and diesel fuels.
Another object of this invention is to provide a method of making a novel sorbent which is useful in the desulfurization of such hydrocarbon-containing fluid streams.
Still another object of this invention is to provide a process for the removal of sulfur-containing compounds from hydrocarbon-containing fluid streams which minimizes saturation of olefins and aromatics therein.
A further object of this invention is to provide a process for the removal of sulfur-containing compounds from hydrocarbon-containing fluid streams which minimizes hydrogen consumption.
It should be noted that the above-listed objects need not all be accomplished by the invention claimed herein and other objects and advantages of this invention will be apparent from the following description of the invention and appended claims.
In one aspect of the present invention, there is provided a novel sorbent composition suitable for removing sulfur from a hydrocarbon-containing fluid. The sorbent composition comprises a reduced-valence noble metal, zinc oxide, and a carrier.
In accordance with another aspect of the present invention, there is provided a process of making a sorbent composition. The process comprises the steps of: admixing zinc oxide and a carrier so as to form a support mix; particulating the support mix so as to form a support particulate; incorporating the support particulate with a noble metal or a noble metal-containing compound to provide a promoted particulate comprising an unreduced noble metal; and reducing the promoted particulate to provide a reduced sorbent composition comprising a reduced-valence noble metal.
In accordance with a further aspect of the present invention, there is provided a process for removing sulfur from a hydrocarbon-containing fluid stream. The process comprises the steps of: contacting the hydrocarbon-containing fluid stream with a sorbent composition comprising a reduced-valence noble metal and a support in a desulfurization zone under conditions such that there is formed a desulfurized fluid stream and a sulfurized sorbent; separating the desulfurized fluid stream from the sulfurized sorbent; regenerating at least a portion of the separated sulfurized sorbent in a regeneration zone so as to remove at least a portion of the sulfur therefrom and provide a regenerated desulfurized sorbent; reducing the desulfurized sorbent in an activation zone to provide a reduced sorbent composition which will effect the removal of sulfur from the hydrocarbon-containing fluid stream when contacted with the same; and returning at least a portion of the reduced sorbent composition to the desulfurization zone.
DETAILED DESCRIPTION OF THE INVENTION
In accordance with a first embodiment of the present invention, a novel sorbent composition suitable for removing sulfur from hydrocarbon-containing fluids is provided. The sorbent composition comprises a support and a reduced-valence noble metal.
The support may be any component or combination of components which can be used as a support for the sorbent composition of the present invention to help promote the desulfurization process of the present invention. Preferably, the support is an active component of the sorbent composition. Examples of suitable support components include, but are not limited to, zinc oxide and any suitable inorganic and/or organic carriers. Examples of suitable inorganic carriers include, but are not limited to, silica, silica gel, alumina, diatomaceous earth, expanded perlite, kieselguhr, silica-alumina, titania, zirconia, zinc aluminate, zinc titanate, zinc silicate, magnesium aluminate, magnesium titanate, synthetic zeolites, natural zeolites, and combinations thereof. Examples of suitable organic carriers include, but are not limited to, activated carbon, coke, charcoal, carbon-containing molecular sieves, and combinations thereof. A preferred support comprises zinc oxide, silica, and alumina.
When the support comprises zinc oxide, the zinc oxide used in the preparation of the sorbent composition of the present invention can be either in the form of zinc oxide, such as powdered zinc oxide, or in the form of one or more zinc compounds that are convertible to zinc oxide under the conditions of preparation described herein. Examples of suitable zinc compounds include, but are not limited to, zinc sulfide, zinc sulfate, zinc hydroxide, zinc carbonate, zinc acetate, zinc nitrate, and combinations thereof. Preferably, the zinc oxide is in the form of powdered zinc oxide.
When the support comprises zinc oxide, the zinc oxide will generally be present in the sorbent composition of the present invention in an amount in the range of from about 10 to about 90 weight percent zinc oxide based on the total weight of the sorbent composition, preferably in an amount in the range of from about 15 to about 80 weight percent zinc oxide, and most preferably in an amount in the range of from 20 to 70 weight percent zinc oxide.
When the support comprises silica, the silica used in the preparation of the sorbent composition of the present invention can be either in the form of silica or in the form of one or more silicon compounds. Any suitable type of silica may be employed in preparing the sorbent composition of the present invention. Examples of suitable types of silica include, but are not limited to, diatomite, expanded perlite, silicalite, silica colloid, flame-hydrolyzed silica, hydrolyzed silica, silica gel, precipitated silica, and combinations thereof. In addition, silicon compounds that are convertible to silica such as silicic acid, ammonium silicate and the like and combinations thereof can also be employed. Preferably, the silica is in the form of diatomite or expanded perlite.
When the
Arnold Jr. James
ConocoPhillips Company
Griffin Walter D.
Jolly Lynda S.
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