Sulfur reduction of naphtha with membrane technology
A novel process based on membrane separation for production of low sulfur gasoline was presented. Compared to conventional sulfur reduction methods, the process requires less capital investment and minimizes octane loss. The process splits naphtha into a major stream with < 30 ppm wt sulfur species, and a minor stream that is highly enriched in sulfur species. After treating the high sulfur stream with conventional sulfur reduction technologies and recombining with the major stream, the sulfur content of the total naphtha stream could be reduced to < 30 ppm. The permeate stream is not enriched in olefins and protects olefins from hydrogenation, thus octane loss is minimized. Changes in feed composition and process conditions impact membrane performance and process design. The pilot plant could be configured to demonstrate stable operation under constant feed composition or run in the mode where permeate is continuously withdrawn and segregated to yield low sulfur gasoline in the retained feed.