Reduction of sulfur content in transportation fuels has received increasing attention with growing environmental awareness. Sulfur in gasoline is a considerable source of SO x emissions. Toxicity of sulphur compounds, which by the combustion of motor fuel enters the atmosphere, are primarily associated with the formation of acid rain, which further contribute to the acidifi cation of soil and surface water, as well as the formation of photochemical smog. It is impossible to mention the harmful effects of sulfur compounds in the increased concentration on the organisms. The negative effect of sulfur compounds during combustion of fuel, is also seen in the form of corrosion of metals and concrete, paper aging or destruction of plastics (Brunet et al. 2005, Lefl aive et al. 2002, Song 2003. Moreover, the presence of sulfur oxides in exhaust gases from vehicles contributes to the larger emission of NO x and VOC's caused by the reduction of low-temperature catalytic converters activity. Therefore, many countries adopt new and more rigorous regulations on sulfur content in gasoline. The specifi cation in EU countries, demands a reduction of sulfur level in gasoline and Diesel fuels to 10 ppm (Directive 2009).Nearly all of the sulfur (85-95%) in the typical refi nery plant comes from Fluid Catalytic Cracking (FCC) gasoline, and a small amount originates from light straight run, reforming and isomerisation units. That is why, FCC gasoline is the natural substance to focus on sulfur reduction. The sulfur concentration of FCC gasoline depends on the sulfur type and its level in the FCC feedstock (Brunet et al. 2005). Although elemental sulfur, mercaptans, sulfi des, disulfi des, thiophene and its homologues are all present in petroleum or in petroleum fractions, sulfur occurs mainly in the form of thiophene, sulfi des, mercaptans and disulfi des (Lefl aive et al. 2002).A lot of effort is now spent on developing novel and effi cient hydrogen and non-hydrogen desulfurization technologies such as selective extraction, catalytic extraction, selective oxidation, bio-desulfurization, alkylation-extraction, improved selective hydroprocessing and pervaporative desulfurization (PVDS) (Ito et al. 2006, Song 2003. It should be noted that this new desulfurization technology has already progressed beyond the lab-scale tests stage. In comparison with the traditional and other non-HDS separation processes, membrane separation offers many advantages including lower energy consumption and operating cost, simple operation and control scheme, easy scale up, higher separation effi ciency and adaptability to changes in process streams (Kujawski 2009, White 2006. Those promising advantages make membrane separation an attractive process for many of recent researches.
TheoryPervaporation process principle Pervaporation is a membrane technology utilizing a dense non-porous homogeneous polymeric fi lm. The liquid solute selectively dissolves and diffuses in the membrane and is removed as vapour at the downstream side. The vacuum pervaporation is c...