Electrolysis: processes – compositions used therein – and methods – Electrolytic material treatment – Organic
Reexamination Certificate
2000-03-31
2001-08-14
Phasge, Arun S. (Department: 1741)
Electrolysis: processes, compositions used therein, and methods
Electrolytic material treatment
Organic
C204S559000
Reexamination Certificate
active
06274026
ABSTRACT:
FIELD OF THE INVENTION
An embodiment of the instant invention is directed to an electrochemical process that removes sulfur from a naphtha feed stream while preserving octane number.
BACKGROUND OF THE INVENTION
Due to environmental regulations the amount of sulfur present in gasoline streams must be closely controlled. Gasoline is typically made up of a mixture of (
1
) naphthas from fluid catalytic cracking processes, (
2
) reformate from catalytic reforming processes, (
3
) alkylate from acid-catalyzed alkylation processes and (
4
) various additives. Almost all of the sulfur in gasoline is contributed by the naphtha component. The regulations will require the amount of sulfur in gasoline to be reduced to about 150 ppm by the year 2000, with further reduction to about 30 ppm by the year 2004. Thus, there is a critical need for technologies that are capable of lowering the amount of sulfur present in naphtha streams.
Present technology for lowering the amount of sulfur in naphtha streams, which is based on catalytic hydrotreating, results in an octane loss due to saturation of olefins present in the naphthas. Thus, following the sulfur removal, octane must be replaced. In the Mobil Oct-Gain and Intevep ISAL processes, for instance, the desulfurized product is isomerized, resulting in an increase in octane but at a substantial yield loss.
SUMMARY OF THE INVENTION
An embodiment of the instant invention is directed to an electrochemical process for removing sulfur from a stream comprising hydrocarbon and polymerizable sulfur compounds comprising:
(a) combining a hydrocarbon feed containing polymerizable sulfur compounds with an ionic liquid;
(b) electrochemically oxidizing said combination of step (a) in an electrochemical reactor, under conditions capable of producing sulfur oligomers from said polymerizable sulfur compounds to obtain a first fraction comprising sulfur oligomers, ionic liquid, and entrained hydrocarbon, and a second fraction comprising desulfurized hydrocarbon;
(c) recovering said first fraction and said second fraction.
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Newman, D. S.; Kurt, E. M.; Chen, D.; “The Desulfurization of Coal and Model Coal Compounds in Ambient Temperature Molten Salts”, Prepr. Pap. -Am. CHem. Soc., Div.Fuel Chem. 33(3), 113-19, 1988.
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Baird, Jr. William Chalmers
Schucker Robert Charles
Bakun Estelle C.
ExxonMobil Research and Engineering Company
Phasge Arun S,.
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