Effect investigation of ZnO additive on Mn-Fe/γ-Al2O3 sorbents for hot gas desulfurization

The effect of the molar ratio of Mn:Fe on Mn-Fe/gamma-Al2O3 sorbent performance for hot gas desulfurization was studied in detail in this paper. The results showed that the ideal composition for preparation of Mn-Fe/gamma-Al2O3 was a molar ratio of two, i.e. AMF2.0 sorbent, for the temperature range of 500-650 degreesC. The regenerated AMF2.0 sorbent desulfurization results showed that its reactivity was decreased when the reaction-regeneration cycles were more than seven at 700 degreesC, using 3.0 vol.% oxygen diluted with nitrogen as regeneration conditions. When a small amount of ZnO was added to the AMF2.0 sorbent, its performance in removal of H2S was improved at the experimental conditions. The optimum composition for preparation of Mn-Fe-Zn/gamma-Al2O3 was a 2:1:0.2 molar ratio of Mn:Fe:Zn, i.e. AMFZ0.2 sorbent. At the same regeneration conditions used for Mn-Fe/gamma-Al2O3 sorbents, it was shown that the regenerated AMFZ0.2 sorbent had better desulfurization stability, which implied the AMFZ0.2 sorbent could be an ideal sorbent for removal of H2S at high temperature for hot gas desulfurization. (C) 2002 Elsevier Science Ltd. All rights reserved.