Fractionation for full boiling range gasoline desulfurization
First Claim
1. In a process for the treatment of an FCC naphtha fraction to remove sulfur containing compounds wherein the FCC naphtha fraction is separated by fractional distillation yielding at least light and heavy fractions, the improvement which comprises performing the fractional distillation in a dividing wall column and producing an intermediate fraction comprising C7 olefins and thiophene.
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Accused Products
Abstract
Savings in the processing of a naphtha boiling range feed containing a thiophene are achieved by fractionating the feed stream in a single dividing wall column to yield a C6-minus overhead stream, a side-draw containing the majority of the C6 and C7 paraffins and olefins, and a bottoms stream comprising C7 and heavier hydrocarbons. A dividing wall column provides better control of the concentration of both thiophene and toluene in the side-draw. Less of the valuable naphtha is lost and the amount of thiophene in the overhead product is minimized.
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Citations
10 Claims
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1. In a process for the treatment of an FCC naphtha fraction to remove sulfur containing compounds wherein the FCC naphtha fraction is separated by fractional distillation yielding at least light and heavy fractions, the improvement which comprises performing the fractional distillation in a dividing wall column and producing an intermediate fraction comprising C7 olefins and thiophene.
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2. A process for the desulfurization of a naphtha boiling range feed stock comprising sulfur compounds, which process comprises:
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a.) passing the feedstock into a dividing wall column and separating the feed stock into a light fraction comprising mercaptans, olefinic hydrocarbons and paraffinic hydrocarbons having less than six carbon atoms, an intermediate fraction comprising C6 and C7 olefinic hydrocarbons and thiophene, and a heavy fraction which comprises sulfur compounds and hydrocarbons containing more than seven carbon atoms per molecule;
b.) passing the light fraction into an extractive first treating zone in which mercaptans are removed by contact with an aqueous alkaline solution to form a first treated stream;
c.) treating the intermediate fraction in a second treating zone, in which thiophenes are removed, to form a second treated stream;
d.) treating the heavy fraction in a third treating zone, in which sulfur containing compounds are subjected to hydrotreating, to form a third treated stream; and
e.) recovering treated products. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10)
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Specification