Ultra-Deep Desulfurization of Ultra-Low Sulfur Diesel over Nickel-Based Sorbents in the Presence of Hydrogen for Fuel Cell Applications

摘要

This study explored the addition of H_2 to improve the sorption performance of the nickel-based sorbents in ultra-deep desulfurization of ultra-low sulfur diesel (ULSD). The desulfurization of ULSD over Raney Nickel and Ni20/SBA-15 was conducted in a fixed-bed sorption system at 220C and ambient pressure in the absence and presence of H_2. The ADS performances of the prepared nickel-based sorbent and commercial Raney Nickel in the absence and presence of H_2 were evaluated and compared. Addition of very small amount of H_2 into the sorption system significantly increases the adsorptive capacity of the SBA-15-supported nickel-based sorbent for desulfurization of ULSD. The improvement of the sorption performance is through accelerating the C-S bond cracking of the adsorbed sulfur compounds to release the corresponding hydrocarbon part from the surface, and thus to provide more exposed nickel atoms on the surface to interact with other sulfur compounds. Each kilogram of the prepared Ni20/SBA-15 sorbent is able to treat about 240 L of the commercial ULSD with sulfur content of 14.5 ppmw to get a desulfurized fuel with sulfur content less than 1 ppmw in the presence of H_2.