Hot gas desulfurization with vanadium-promoted zinc ferrite sorbents

Abstract

The performance of zinc ferrite promoted with V₂O₅ was investigated as a hot gas desulfurization sorbent. The sorbents were prepared by the incipient impregnation technique, and the vanadium loading and the calcination temperature were varied. The sorbents were tested in a packed-bed microreactor set-up for five sulfidation-regeneration cycles to investigate their breakthrough behaviour. Sulfidation was performed at 873–973 K with H₂S-H₂-H₂O-N₂ mixtures, while regeneration was carried out at 923–973 K with O₂-N₂ mixtures. The fresh, sulfided, and regenerated sorbents were characterized by atomic absorption spectroscopy, X-ray diffraction, surface area and porosity measurements. The results of the investigation indicated that the sorbents exhibited a more stable cyclic performance with higher vanadium loading, all vanadium-promoted sorbents reduced the H₂S content of the gas to levels below the equilibrium level for zinc oxide, some H₂S was chemisorbed by vanadium, and two-step calcination imparted structural stability to the sorbents.