CuO-WO3/TiO2催化氧化燃煤烟气中Hg0试验研究

提高燃煤电厂现有选择性催化还原（SCR）催化剂催化氧化单质汞（Hg⁰）的性能，能够有效增强燃煤电厂利用现有烟气污染物控制装置协同脱汞效率。采用分步浸渍法制备了一系列CuO-WO₃/TiO₂（CuWTi）催化剂，在温度150~350 ℃时模拟燃煤烟气条件，考察了催化氧化Hg⁰性能，并与商用脱硝催化剂进行了比较。探究了烟气中O₂、SO₂和NO等气体对Hg⁰氧化性能的影响规律。发现商用脱硝催化剂和WTi催化剂在不含HCl的模拟烟气中对Hg⁰氧化率均在30%以下，而Cu₂W₈Ti催化剂具有较好的Hg⁰氧化性能。采用X射线光电子能谱分析仪（XPS）对催化剂进行了表征，结果表明，CuO与WO₃的相互作用在催化剂表面生成了丰富的化学吸附氧，促进了Hg⁰的氧化。Hg⁰在Cu₂W₈Ti催化剂表面的氧化过程遵循Mars-Maessen机制。

Catalytic Oxidation of Elemental Mercury over CuO-WO3/TiO2 in Simulated Coal-fired Flue Gas

Improving the Hg⁰ oxidation activity of the commercial selective catalytic reduction (SCR) catalyst can enhance the mercury removal activity in coal fired flue gas. In this paper, a series of CuO-WO₃/TiO₂ (CuWTi) catalysts were synthesized by step impregnation method for oxidize elemental mercury (Hg⁰) using simulated coal-fired flue gas at 150-350 ℃. The effects of O₂, SO₂ and NO on Hg⁰ oxidation were also investigated and compared with commercial catalyst. The results indicated that the commercial SCR catalyst and the WTi exhibited below 30% rate on Hg⁰ oxidation without HCl in simulated flue gas, while the Cu₂W₈Ti catalyst performed good activity of Hg⁰ oxidation and NO removal. The X-ray photoelectron spectroscopy (XPS) method was used to characterize the catalysts, and the results suggested that the interaction between CuO and WO₃ created abundant chemisorbed oxygen on the catalyst surface, which was beneficial for Hg⁰ oxidation. The Mars-Maessen mechanism was respected in the process of the Hg⁰ oxidation over Cu₂W₈Ti catalyst.