Energy & Fuels, Vol.31, No.12, 13921-13932, 2017
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 (Fe2O3/Al2O3) was prepared by the sol-gel method. The performance of sorbents was evaluated at 500 degrees C over a fixed-bed reactor. A mixture of SO2, 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 Fe2O3 are achieved for the sorbents (35% Fe2O3) calcinated at 500 degrees C for 3 h. The sorbents should be regenerated at above 500 C due to the formation of Fe-2(SO4)(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(SO4)(3) and Al3Fe5O12. The main sulfur-containing regeneration product is elemental sulfur under the optimum regeneration conditions. gamma-Fe2O3 and alpha-Fe2O3 coexist in the regenerated sorbents. In addition, the Fe2O3/Al2O3 desulfurizers show good performance with durable regeneration ability during five desulfurization/regeneration cycles.