Investigation on elemental mercury removal and antideactivation performance of modified SCR catalysts

Abstract The ever‐growing concern of mercury exhausted from coal‐fired boiler is driving the requirement for using novel catalysts with stable Hg0 removal efficiency. However, the influences of flue gas components on Hg0 removal performance of modified and deactivated catalysts have been seldom investigated previously. The antideactivation ability of modified catalysts is still unclear. In this study, cerium (Ce) and zirconium (Zr) were utilized to modify the honeycomb V2O5–WO3/TiO2 catalysts. Sodium (Na) was doped on the rudimentary and modified catalysts by impregnation method to obtain deactivated catalysts. Elemental mercury removal efficiency of the catalysts was measured using a lab‐scale experimental system under various working conditions. Characterization of the catalysts was conducted to further analyze the mechanism of Hg0 removal process. Physical adsorption plays an important role in Hg0 removal over catalysts in the atmosphere of N2 and O2. The introduction of SO2 has an adverse effect on Hg0 removal because of the competitive adsorption. NO and HCl motivate the Hg0 removal through different mechanisms whereas NH3 has little effect on the removal efficiency. Mars–Maessen mode could be responsible for the excellent Hg0 removal performance and the splendid antideactivation ability of Ce‐modified catalysts. The efficiency of Zr‐modified catalysts is lower due to the decline of vanadium content.