Fe2O3-SiO2 particles, which removes H2S and COS in hot coal gas, are prepar
ed. The characteristics of sulfidation are studied using simulated coal gas
from an air blown gasifier.
In the temperature range of 623 K to 973 K, the conversion rate of Fe2O3-Si
O2 particle to iron sulfide was slowest at 823 K where Fe2SiO4 is formed at
reduction before sulfidation. At lower than 823 K, the stable formation is
Fe3O4. The conversion rate is of first order in H2S concentration. At more
than 823 K. however sulfidation does not proceed in lower H2S concentratio
n than 1,000 ppm-2,500 ppm levels. At temperature 823 K, this concentration
is lower than 2,460 ppm, which is higher than the equilibrium concentratio
ns (175 ppm).
In the temperature ranges from 673 K to 823 K and from 923 K to 973 K. sulf
idation is controlled by pore diffusion under Knudsen diffusion regime. Thi
s result shows that sulfidation has the influence of the change of pore rad
ius of Fe2O3-SiO2 particle at reduction.