Effect of Ce modification on desulfurization performance of regenerated sorbent for high temperature H2S removal from coal gas

Abstract

Ce modified MnxOy/Al2O3-La have been prepared to investigate the effect of Ce loadings on pre-breakthrough H2S removal efficiency, breakthrough sulfur capacity (BSC) and BSC durability of the sorbents during desulfurization-regeneration cycles. The results showed Ce modification could improve the pre-breakthrough H2S removal efficiency of regenerated sorbents during desulfurization-regeneration cycles. The XPS characterization showed that the Ce can promote the binding energy of Mn ion to shift to lower energy, which enhanced H2S adsorption on the regenerated sorbent. However, the Ce loading sequence had effect on BSC durability of sorbent during desulfurization-regeneration cycles. The Ce-MnxOy/Al2O3-La with co-impregnation of Mn and Ce oxides had higher BSC than MnxOy/Al2O3-La, while the Ce/MnxOy/Al2O3-La with Ce loading on the surface of MnxOy/Al2O3-La had lower BSC and worse BSC durability than MnxOy/Al2O3-La. The characterization results showed Ce-MnxOy/Al2O3-La obtained better surface area and pore structure than MnxOy/Al2O3-La, and Ce ion can promote the increasing of the around electron density of Mn ion, which was beneficial for H2S adsorption of Ce-MnxOy/Al2O3-La. The poor surface area and pore structure would cause the low BSC of Ce/MnxOy/Al2O3-La, and less stability of pore structure might lead to poorer BSC durability of Ce/MnxOy/Al2O3-La than MnxOy/Al2O3-La during desulfurization-regeneration cycles.