一种改性选择性催化还原催化剂及其对零价汞的催化氧化性能

A Modified Selective Catalytic Reduction Catalyst and Its Catalytic Oxidation for Hg0

利用溶液浸渍法制备了一种氯化铜改性的选择性催化还原（SCR）催化剂（Cu Cl2/SCR）。用X射线衍射（XRD）和X射线荧光光谱分析（XRF）等对Cu Cl2/SCR催化剂的结构进行了表征,在自制的催化剂活性实验台上,用模拟烟气对催化剂Hg0的催化氧化性能进行了研究。结果表明：催化剂中的Cu Cl2在高温（HCl＋O2）气氛中能＂可逆＂释放活性氯;Cu Cl2的引入显著提高了催化剂在低氯烟气（HCl浓度在0~81.5 mg/m3）中对Hg0的催化氧化效率;Hg0的氧化率随烟气中HCl浓度和催化剂中Cu Cl2负载量的增加而增加;烟气中的NH3和SO2能阻止Hg0在催化剂表面的吸附,导致Cu Cl2/SCR催化剂在SCR条件下对Hg0的催化氧化效率较纯氧化条件有所降低,但Cu Cl2/SCR仍保持了较高的Hg0催化氧化效率（可高达98%）;Cu Cl2/SCR催化氧化Hg0的机制为Mars-Maessen机制。Cu Cl2/SCR兼具较高的脱硝性能和Hg0氧化性,可用于低氯燃煤烟气同时脱硝脱汞。

A Cu Cl2 modified selective catalytic reduction（SCR） catalyst（Cu Cl2/SCR） was prepared by impregnation method. The catalyst was characterized by（X-ray diffractometer（XRD）, X-ray fluorescence（XRF） and other techniques, and its catalytic activity for Hg0 oxidation was also evaluated on a homemade laboratory bench by using simulated flue gas. It was found that the Cu Cl2/SCR catalyst can release active chlorine in a reversible way at high temperature in the presence of HCl and O2. Embedding Cu Cl2 into SCR catalyst improves significantly the catalytic activity for Hg0 oxidation of the catalyst in the flue gas with low chlorine contents. For the Cu Cl2/SCR catalyst the Hg0 oxidation efficiency increases with the HCl content in the flue gas and the Cu Cl2-loaded amount of the catalyst. NH3 and SO2 can inhibit Hg0 adsorption on the catalyst surface, which results in a slight decrease in the catalytic activity of Cu Cl2/SCR catalyst. However, it still shows high catalytic oxidation for Hg0, and the catalytic mechanism belong Mars-Maessen mode. The prepared catalyst also exhibits high denitration activity, therefore it can be used for simultaneous removal of NO and Hg in the flue gas with low chlorine contents.