Significance of RuO2 Modified SCR Catalyst for Elemental Mercury Oxidation in Coal-fired Flue Gas

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• 作者：Naiqiang Yan ; Wanmiao Chen ; Jie Chen ; Zan Qu ; Yongfu Guo ; Shijian Yang ; Jinping Jia
• 刊名：Environmental Science & Technology
• 出版年：2011
• 出版时间：July 1, 2011
• 年：2011
• 卷：45
• 期：13
• 页码：5725-5730
• 全文大小：931K
• 年卷期：v.45,no.13(July 1, 2011)
• ISSN：1520-5851

文摘

Catalytic conversion of elemental mercury (Hg⁰) to its oxidized form has been considered as an effective way to enhance mercury removal from coal-fired power plants. In order to make good use of the existing selective catalytic reduction of NO_x (SCR) catalysts as a cobenefit of Hg⁰ conversion at lower level HCl in flue gas, various catalysts supported on titanium dioxide (TiO₂) and commercial SCR catalysts were investigated at various cases. Among the tested catalysts, ruthenium oxides (RuO₂) not only showed rather high catalytic activity on Hg⁰ oxidation by itself, but also appeared to be well cooperative with the commercial SCR catalyst for Hg⁰ conversion. In addition, the modified SCR catalyst with RuO₂ displayed an excellent tolerance to SO₂ and ammonia without any distinct negative effects on NO_x reduction and SO₂ conversion. The demanded HCl concentration for Hg⁰ oxidation can be reduced dramatically, and Hg⁰ oxidation efficiency over RuO₂ doped SCR catalyst was over 90% even at about 5 ppm HCl in the simulated gases. Ru modified SCR catalyst shows a promising prospect for the cobenefit of mercury emission control.