Desulfurization of Hot Coal Gas over Regenerable Low-Cost Fe2O3/Mesoporous Al2O3 Prepared by the Sol–Gel Method

Low-cost Fe-based sorbent supported on mesoporous alumina (Fe 2 O 3 /Al 2 O 3 ) was prepared by the sol–gel method. The performance of sorbents was evaluated at 500 °C over a fixed-bed reactor. A mixture of SO 2, O 2, and N 2 in various proportions was used to regenerate the sorbents after desulfurization. The structure of sorbents before and after desulfurization was characterized using N 2 adsorption, XRD, SEM, and XPS techniques. The results indicate that high sulfur capacity (12.5%) and utilization rate (88.6%) of Fe 2 O 3 are achieved for the sorbents (35% Fe 2 O 3 ) calcinated at 500 °C for 3 h. The sorbents should be regenerated at above 500 °C due to the formation of Fe 2 (SO 4 ) 3 at low temperature, while increasing regeneration temperature from 600 to 650 °C leads to a decrease of the regeneration rate resulting from the production of Al 2 (SO 4 ) 3 and Al 3 Fe 5 O 12 . The main sulfur-containing regeneration product is elemental sulfur under the optimum regeneration conditions. γ-Fe 2 O 3 and α-Fe 2 O 3 coexist in the regenerated sorbents. In addition, the Fe 2 O 3 /Al 2 O 3 desulfurizers show good performance with durable regeneration ability during five desulfurization/regeneration cycles.