Patent ID: 6059962
Filing Date: 2000-05-09
Classification: C10G

Abstract:
A process for producing products of reduced sulfur content from a feedstock, wherein said feedstock is comprised of a mixture of hydrocarbons which includes olefins, and wherein the feedstock contains sulfur-containing aromatic compounds as impurities; said process comprising:(a) in a first contacting step, contacting the feedstock with an acidic catalyst under conditions which are effective to convert a portion of the impurities to a sulfur-containing material of higher boiling point through alkylation by the olefins;(b) in a first fractionation step, fractionating the product of said first contacting step on the basis of boiling point into at least two fractions which include:(i) a first fraction which is comprised of hydrocarbons and has a reduced sulfur content relative to that of said feedstock; and(ii) a second fraction which is comprised of hydrocarbons, has a higher boiling point than that of said first fraction and contains sulfur-containing aromatic compounds as impurities;(c) withdrawing said first fraction from the process as a first product stream of reduced sulfur content;(d) preparing a secondary process stream by combining said second fraction with a secondary alkylating agent which is comprised of at least one material selected from the group consisting of alcohols and olefins, and wherein said secondary alkylating agent is in addition to any olefins present in the second fraction;(e) in a second contacting step, contacting the secondary process stream with an acidic catalyst under conditions which are effective to convert at least a portion of the sulfur-containing aromatic compounds in said secondary process stream to a sulfur-containing material of higher boiling point;(f) in a second fractionation step, fractionating the product of said second contacting step on the basis of boiling point to remove high boiling sulfur-containing material in a high boiling fraction and produce a lower boiling fraction; and(g) withdrawing the lower boiling fraction from the second fractionation step as a second product stream of reduced sulfur content.