Catalytic performance and sulfur resistance of OMS-2 modified by copper for mercury removal at low temperature

• Published in: Fuel (Guildford) 2023-01, Vol.332, p.126040, Article 126040
• Main Authors: Han, Jun, Shan, Weiwei, Zhao, Bo, Wang, Yiming, Zhang, Qiang, Qin, Linbo, Chen, Wangsheng
• Format: Article
• Language: English
• Subjects: Catalytic oxidation; Copper; Elemental mercury; Manganese oxide molecular sieve; Sulfur resistance
• ISSN: 0016-2361
• DOI: 10.1016/j.fuel.2022.126040

•Cu dopant on OMS-2 greatly improves the surface area and active sites of catalyst.•Hg0 removal efficiency of Cu0.05-OMS-2 is 92 % even in the presence of 1000 ppm SO2.•Cu-OMS-2 shows strong sulfur resistance for the protection of Cu on active sites. Cu-doped manganese oxide molecular sieve catalysts (Cu-OMS-2) are prepared by hydrothermal synthesis method, and their Hg0 removal ability and sulfur resistance are investigated experimentally under simulated flue gas conditions. It indicated that appropriate proportion of Cu doped could increase both the content of Mn4+ active sites on the catalyst surface and the BET specific surface area. The maximum specific surface area of these catalysts is 260.49 m2/g, with the Cu/Mn molar ratio of 0.025. A highest Hg0 removal efficiency of 93.6 % is achieved by the catalyst with Cu/Mn molar ratio of 0.05. SO2 in flue gas significantly inhibits the Hg0 removal ability of OMS-2-H120, but its suppression ability is relatively weak after the addition of Cu to OMS-2-H120. The Hg0 removal efficiency of Cu0.05-OMS-2 can reach 92 % even in the presence of 1000 ppm SO2. The doping of Cu on OMS-2 enhances SO2 adsorbed by CuO, inhibiting the reaction of SO2 with the active center on the catalyst surface. It reduces the generation of sulfate and enhances the sulfur resistance ability of Cu0.05-OMS-2. The process of Hg0 oxidation by O2 over Cu0.05-OMS-2 is found to follow Mars-Maessen mechanism based on the characteristics of fresh and spent catalysts. Elemental mercury is firstly chemisorbed on the Cu0.05-OMS-2 catalyst surface and then oxidized.