(343c) Desulfurization of Commercial Fuels Using Mixed Oxide Supported Silver Adsorbents At Room Temperature for Fuel Cell Applications

Sulfur removal from petroleum fuels is a major challenge globally due to ever growing demand of sulfur free feedstock for fuel cell applications. Adsorption of organosulfur compounds from hydrocarbon fuels at ambient conditions is a promising solution to the high energy and processing cost requirements for ultra clean fuel production. In this work, the performances of Ag adsorbents supported on titania dispersed alumina (TiO₂-Al₂O₃) for desulfurizing JP5, JP8 jet fuels and off-road diesel have been discussed. Sulfur adsorption capacities were obtained through observation of breakthrough of commercial fuels. Model fuels containing thiol and thiophene derivatives and aromatic compounds were used in breakthrough experiments to study the selectivity of the adsorbent toward sulfur species. N₂ physisorption, TPR, XRD, and in situ FTIR were employed to characterize the adsorbent. In the breakthrough experiments, 12% by weight Ag supported on TiO₂-Al₂O₃ adsorbent had respected saturation capacities of 11.83, 8.01, and 10.9 mg S/g sorbent for desulfurizing JP5, JP8, and off-road diesel (initial sulfur contents of 1172, 630, and 452 ppmw, respectively). Mixed oxide TiO₂-Al₂O₃ support provided seats for more dispersed and oxidized silver as observed from TPR and XRD. Breakthrough of model fuels revealed that the aromatic rings are essential for adsorption onto silver adsorbent. The sulfur capacity of the adsorbent was reduced in presence of other aromatic compounds. Infrared spectra of the samples treated with sulfur and aromatic compounds detected both physisorbed and chemisorbed sulfur species on Ag/TiO₂-Al₂O₃ adsorbent.