Ultra-deep desulfurization via reactive adsorption on nickel and zinc species supported on activated carbon

The reactive adsorption desulfurization behavior of the Ni and Zn metal species supported on the activated carbon were investigated. The adsorbents were prepared by incipient wetness impregnation of the carbon support with aqueous solutions of nickel nitrate, zinc nitrate and nitrilotriacetic acid. The impregnated precursors transfer to ZnO and Ni3ZnC0.7 phase after calcination in nitrogen, and partially convert to NiZn alloy by hydrogen reduction treatment. The residual Ni3ZnC0.7 phase of the reduced adsorbents can be consumed slowly in the desulfurization process. The sulfur content of outflow oil can be readily decreased from original 640 ppmw to near zero residual sulfur with a breakthrough sulfur capacity of 106.5 mg-S/g-adsorbent, corresponding to 490 mg-S/g-(NiO + ZnO). The high efficiency of the adsorbents suggests that the release of metallic Ni from NiZn alloy is sufficiently rapid to provide an active phase for desulfurization and the formation of NiZn alloy is also favorable for the contact between Ni and Zn species which could accelerate the sulfur transfer from Ni3S2 to Zn phase.