The mechanism of coal gas desulfurization by iron oxide sorbents

This study aims to understand the roles of hydrogen and carbon monoxide during the desulfurization process in a coal gasification system that H₂S of the syngas was removed by Fe₂O₃/SiO₂ sorbents. The Fe₂O₃/SiO₂ sorbents were prepared by incipient wetness impregnation. Through the breakthrough experiments and Fourier transform infrared spectroscopy analyses, the overall desulfurization mechanism of the Fe₂O₃/SiO₂ sorbents was proposed in this study. The results show that the major reaction route is that Fe₂O₃ reacts with H₂S to form FeS, and the existence of CO and H₂ in the simulated gas significantly affects equilibrium concentrations of H₂S and COS. The formation of COS occurs when the feeding gas is blended with CO and H₂S, or CO₂ and H₂S. The pathways in the formation of products from the desulfurization process by the reaction of Fe₂O₃ with H₂S have been successfully established.