Industrial & Engineering Chemistry Research, Vol.45, No.22, 7649-7655, 2006
Desulfurization of high-sulfur jet fuel by pi-complexation with copper and palladium halide sorbents
Deep desulfurization of a high-sulfur jet fuel (for fuel cell applications) was achieved by adsorption with pi-complexation sorbents. The total sulfur content of JP-5 jet fuel was removed from 1172 ppmw S to below 1 ppmw S. The following sorbents were prepared and tested: CuCl supported on activated carbon (CuCl/ AC), PdCl2/AC, PdCl2/Al2O3, and Cu(I)- Y zeolite. Comparison of these sorbents as well as other known sorbents showed that PdCl2/AC had the highest sulfur selectivity and capacity. It was found that significant breakthrough occurred at about 6.0 mL/g for desulfurization of JP-5 by PdCl2/AC. Ab initio molecular orbital computation was performed for the bond energies between different sulfur molecules and these sorbents. For methylated benzothiophene, the main sulfur molecules in jet fuels, the bond energies ( and the separation factors for organosulfur/benzene) followed the order PdCl2 > CuCl > Cu-Y. This result was in agreement with the experimental breakthrough data. The spent PdCl2/AC was regenerated with benzene in a static system, and the regenerated sorbent was tested for reuse. The results showed that similar to 74 wt % adsorbed sulfur could be desorbed and 72% of the sulfur capacity could be recovered for reuse.