The level of sulfur in gasoline has been mandated by the EPA to be 30 ppm or less by January 1 2006 , and U.S. refiners are expected to spend an estimated $8 billion just to meet this sulfur requirement. Unfortunately, the technologies currently being offered to solve this problem result in some loss in either octane or yield, and all are expensive. Membrane pervaporation is the only process currently under consideration that is significantly less expensive, but the membranes being used are not selective enough and cannot operate at elevated temperatures. This project will demonstrate: (1) the synthesis of a unique polymeric membrane with high selectivity to sulfur species and a capability to operate at temperatures above 150ºC, (2) the fabrication of that polymer into a thin film composite membrane form that can be easily scaled to commercial sizes, and (3) the operation of that membrane at the pilot plant stage. During the Phase I, a unique and proprietary high temperature polymer will be synthesized and characterized. It will then be formed into a thin film composite where the active membrane is less than 2 microns in thickness (thus providing improved flux). The membrane will be tested in a laboratory pervaporation unit for its ability to remove sulfur species from a model feed mixture.
Commercial Applications and Other Benefits as described by the awardee: The high temperature pervaporation process should have application in conjunction with existing or planned hydrotreaters, providing a sulfur-lean fraction that bypasses the hydrotreater and effectively reduces the feed rate to it. The additional costs would be far less than the cost of a new hydrotreater
