Elemental Mercury Capture from Syngas by Novel High-Temperature Sorbent Based on Pd–Ce Binary Metal Oxides

Abstract

CeO2 was doped into Pd/Al2O3 using an impregnation method to suppress the interference of H2S and to improve the ability to capture elemental mercury (Hg0) from syngas at high temperatures. As a result, the Hg0 capture performance was generally enhanced by the incorporation of Ce as a result of the consumption of H2S. The individual presence of H2 or CO resulted in the formation of Pd metal responsible for Hg0 capture and active ceria in reduced form for H2S removal, thus promoting the Hg0 removal. Meanwhile, H2S could react with CO to form COS, which competed with Hg0 for active sites, hence inhibiting Hg0 capture. The effect of HCl on Hg0 capture over PCA sorbents was found to be slightly promotional, because a small amount of Hg0 was oxidized to HgCl2. More importantly, the spent PCA sorbents could be easily reactivated, indicating that this material is a prospective candidate for Hg0 control from syngas.