Method and structure for desulfurizing gasoline or diesel fuel for use in a fuel cell power plant

Abstract

A sulfur scrubbing method and structure is operable to remove substantially all of the sulfur present in an undiluted oxygenated hydrocarbon fuel stock supply which can be used to power an internal combustion engine or a fuel cell power plant in a mobile environment, such as an automobile, bus, truck, boat, or the like, or in a stationary environment. The fuel stock can be gasoline, diesel fuel, or other like fuels which contain relatively high levels of organic sulfur compounds such as mercaptans, sulfides, disulfides, thiophenes, and the like. The undiluted hydrocarbon fuel supply is passed through a desulfurizer bed which is provided with a high surface area nickel reactant, and wherein essentially all of the nickel reactant in the scrubber bed reacts with sulfur in the fuel stream, so as to remove sulfur from the fuel stream by converting it to nickel sulfide on the scrubber bed. The desulfurized organic remnants of the fuel stream continue through the remainder of the fuel processing system in the fuel cell power plant, or through the internal combustion engine. The desulfurizer bed is preferably formed from a high surface area ceramic foam monolith, the pores of which are coated with the high surface area nickel reactant. The use of the foam monolith combined with the high surface area of the reactant, enables essentially 100% of the nickel reactant to come into contact with the fuel stream being desulfurized. The scrubber bed can also be formed from high surface area nickel coated alumina pellets, from a high surface area nickel coated ceramic extrusion, from high surface area nickel pellets, and from high surface area nickel extrudates.

Description

TECHNICAL FIELD [0001] The present invention relates to a method and structure for desulfurizing gasoline, diesel fuel or like hydrocarbon fuel streams so as to render the fuel more suitable for use in a mobil vehicular fuel cell power plant assembly or in an internal combustion engine. More particularly, the desulfurizing method and structure of this invention are operable to reduce the amount of organic sulfur compounds found in these fuels to levels which will not poison the catalysts in the fuel processing section of the fuel cell power plant assembly and will not harm components of an internal combustion engine. The method and structure of this invention comprise a highly porous nickel coated reactant bed which has an extended useful life cycle due to the inclusion of the porous nickel coat. The nickel in the coat is reduced from nickel oxide to nickel after being applied to the scrubber bed support. The reduced nickel removes sulfur from the fuel stream by converting the sulfu...

AI Technical Summary

Benefits of technology

"This patent is about an improved method and structure for removing sulfur from gasoline, diesel, and other hydrocarbon fuels. The method involves using a support member with a highly porous nickel oxide material deposited on it. This nickel oxide material has micro pores with randomly distributed micro pores on its surface, resulting in a very large surface area of over 50 square meters per gram of reactant in the scrubber bed structure. The micro porosity and increased surface area greatly increase the amount of nickel in the scrubber bed which is available to react with sulfur in the fuel stream and convert it to nickel sulfide. The nickel sulfide will then be converted to low sulfur content fuel. The invention also includes a method for preventing dehydrogenation of unsaturated hydrocarbons in gasoline, which can lead to the formation of coke precursors and deactivation of the nickel reactant. The use of gasoline containing oxygenates can help prevent this dehydrogenation. Overall, this invention provides a longer lifespan for the scrubber bed and allows for more efficient and effective sulfur removal from hydrocarbon fuels."

Problems solved by technology

When all of the available nickel sites on the scrubber bed surface have been converted to nickel sulfide, then the scrubber bed will be deemed to have reached a “sulfur breakthrough” condition and will be unable to convert further sulfur in the fuel stream to produce the desired low sulfur content fuel.

On the other hand, unsaturated hydrocarbons, such as aromatics and olefins, adsorb largely irreversibly on transition metal surfaces even at room temperature.

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