Industrial & Engineering Chemistry Research, Vol.55, No.5, 1192-1201, 2016
Fe-Promoted Ni/Al2O3 Thioetherification Catalysts with Enhanced Low-Temperature Activity for Removing Mercaptans from Liquefied Petroleum Gas
To enhance the low-temperature activity of monometallic Ni/Al2O3 catalyst for thioetherification, Fe-promoted Ni/Al2O3 catalysts were prepared. The activity of the catalysts was evaluated in a fixed-bed reactor, and their physicochemical properties were characterized. The results showed that the bimetallic NiFe system had significantly improved activity; in particular sample 14Ni(8)Fe/Al2O3 exhibited outstanding activity and stability, with conversions of CH3SH and C2H5SH reaching up to 99.5% and 97.4%, respectively, at 75 degrees C. The promoting effects of Fe include two aspects: (i) Partial incorporated Fe species act as textural promoters, preventing the formation of NiAl2O4, increasing the amount of nickel oxides (NiO and NiFe2O4) weakly interacting with Al2O3, and thereby generating more active sulfides [NiSx and NiS(FeS)] after sulfidation, and (ii) Fe species in a NiS(FeS) phase serving as electron donors supply electron density to the intimately contacted NiS species and weaken the Ni-S bonds, promoting the formation of a NiS(FeS) phase with superior activity.