New sorbents for desulfurization of diesel fuels via π complexation:: Layered beds and regeneration

Desulfurization of a commercial diesel fuel by different layered adsorbents and regeneration of the latter were studied in a fixed-bed unit operated at ambient temperature and pressure. In general, a layered bed consisting of 12 wt % activated carbon, 22 wt % of activated alumina (Selexsorb CDX), followed by Cu(I)-Y, activated carbon/Selexsorb CDX/Cu(I)-Y, is capable of producing 41 cm(3) of desulfurized diesel fuel/g of adsorbent. The matrix is capable of processing 27 cm(3) of deep-desulfurized diesel with a weighted average content of 76 ppbw S. These low-sulfur fuels are suitable for fuel cell applications. For layered-bed regeneration, it was determined that calcination of the adsorbed sulfur moieties with air at 350 degreesC followed by autoreduction of the copper species recovered all of the original desulfurization capacity when activated aluminas are used as a guard layer. Solvent elution experiments indicate that carbon tetrachloride and N,N-dimethylformamide are suitable solvents to recover all of the adsorbed organosulfar species.