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在二氧化硫(SO2)气氛下,对Fe、Cu和V改性的催化剂MnOx-CeOx/ACF(活性碳纤维)的氨选择性催化还原(NH3-SCR)一氧化氮的低温活性进行研究.实验结果表明:以Cu和V改性催化剂未提高MnOx-CeOx/ACF的低温抗SO2性能;Fe改性MnOx-CeOx/ACF在初始6h内提高了催化剂的抗SO2性能,但较长时间仍然失活.以N2吸附、X射线光电子能谱(XPS)、傅里叶变换红外(FT-IR)光谱以及热重分析(TGA)等手段对中毒催化剂进行分析.在SO2存在下,催化剂中毒归因于两个方面:一是覆盖于催化剂表面的铵盐类物质,二是SO2与催化剂中的金属氧化物反应生成的金属硫酸盐及亚硫酸盐.在中毒催化剂中硫元素主要以金属硫酸盐及亚硫酸盐的形式存在,其在中毒的MnOx-CeOx/ACF、Fe-MnOx-CeOx/ACF、Cu-MnOx-CeOx/ACF和V-MnOx-CeOx/ACF催化剂中所占比例分别为70.4%、68.9%、86.3%和71.4%(w).进一步揭示了MnOx-CeOx/ACF催化剂在低温SCR条件下的SO2中毒机理.
The catalytic activity of ammonia-selective catalytic reduction (NH3-SCR) of nitric oxide at MnOx-CeOx / ACF (activated carbon fiber) modified by Fe, Cu and V was investigated in the presence of SO2. : The low temperature SO2 resistance of MnOx-CeOx / ACF was not improved by the Cu and V modified catalysts. The Fe modified MnOx-CeOx / ACF improved the anti-SO2 performance of the catalyst for the first 6 hours, but remained inactive for a long time. N2 adsorption, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric analysis (TGA) were used to analyze the poisoning catalysts. In the presence of SO2, the catalyst poisoning was attributed to two Aspects: First, covering the surface of the catalyst ammonium salts, the second is the reaction of metal oxide and SO2 with the catalyst of the metal sulfates and sulfites in the poisoning of sulfur elements in the catalyst mainly in the metal sulfate and sulfite , Which accounted for 70.4% and 68.9% of the poisoned MnOx-CeOx / ACF, Fe-MnOx-CeOx / ACF, Cu-MnOx- CeOx / ACF and V-MnOx- CeOx / 86.3% and 71.4% (w) respectively.The mechanism of SO2 poisoning of MnOx-CeOx / ACF catalyst under low temperature SCR conditions was further revealed.