Patent ID: 7041212
Filing Date: 2006-05-09
Classification: C10G

Abstract:
1. A method for lowering the sulfur content of a naphtha hydrocarbon feed stream while substantially maintaining the yield of olefin compounds in the feed stream, said method comprising i) contacting a naphtha feed with a membrane separation zone, said separation zone containing a polysiloxane membrane having a sufficient flux and selectivity to separate a sulfur-enriched permeate fraction and a sulfur deficient retentate fraction under pervaporation conditions, said naphtha feed comprising sulfur containing aromatic hydrocarbons, sulfur containing non-aromatic hydrocarbons and olefin compounds, said sulfur enriched permeate fraction being enriched in sulfur containing aromatic hydrocarbons and sulfur containing non-aromatic hydrocarbons as compared to the naphtha feed; ii) recovering the sulfur deficient retentate fraction as a product stream; iii) subjecting the sulfur-enriched permeate fraction to a non-membrane process to reduce sulfur content; and iv) recovering the reduced sulfur permeate product stream, wherein the total amount of olefin compounds present in the retentate product stream and the permeate product stream is at least 50 wt % of olefin compounds present in the feed.