Application of poly(ether imide) membranes for the removal of the aromatic sulphur compounds from gasoline

Abstract

Organic sulphur compounds are regularly present in the crude oil and natural gasoline, mostly as mercaptanes and heterocyclic sulphur compounds. Their combustion products have negative effects to both to the performance of the devices using gasoline and to the environment. Therefore, removal of the sulphur compounds in the pre-combustion process is of a great importance. One of the most promising method is application of the polymeric membranes. Suitable membrane should provide high permeability of sulphur compounds and low permeability of other hydrocarbons. In this work, several membranes based on the poly(ether imide) were tested for the sulphur organic compounds removal from the n-heptane. The membrane separation properties were measured for various concentrations of thiophene in heptane. It was found that increase of the amount of thiophene increases the flux of both thiophene and n-heptane. As the increase of the flux of the n-heptane was higher that the increase of the flux of the thiophene, the selectivity of the polyimide based membrane decreases with the increased concentration of thiophene in the feed. The possible reason is increased mobility of the polymer chains in the active layer.