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以蜂窝状陶瓷为载体,采用溶胶凝胶法和浸渍法制备了不同Fe/Ag负载量的Fe-Ag/Al_2O_3催化剂。以C_3H_6为还原剂,在模拟烟气条件下和200-700℃范围内,程序控温的陶瓷管流动反应器上进行了催化还原NO的性能评估。结果表明,7.2Fe/1.9Ag/20Al_2O_3/CM在500和550℃时催化C_3H_6还原NO的脱硝效率分别超过90%和达到100%。铁离子能有效地提高Ag/20Al_2O_3/CM催化剂抵抗烟气中的SO_2和H_2O的能力。结果表明,当烟气中含有体积分数为0.02%的SO2和8%的H_2O时,在500℃时7.2Fe/1.9Ag/20Al_2O_3/CM催化C_3H_6还原NO的脱硝效率不受影响,在6 h的连续实验中保持90%的脱硝效率而没有下降。而未经铁离子修饰的2Ag/20Al_2O_3/CM的催化活性则受烟气中的SO2和H_2O影响很大,0.02%的SO2和8%的H_2O分别使2Ag/20Al_2O_3/CM在500℃时催化C_3H_6还原NO的脱硝效率迅速从70%分别下降至46%和25%。XRD和SEM表征结果表明,经铁离子修饰后的7.2Fe/1.9Ag/20Al_2O_3/CM催化剂中,形成了AgFeO_2以及Fe~(3+),催化剂表面变得疏松多孔,形成以Fe_3O_4为主的针状和片状晶体。H_2-TPR结果表明,7.2Fe/1.9Ag/20Al_2O_3/CM比Ag/20Al_2O_3/CM在更宽的温度范围内具有更好的还原特性。吡啶吸附红外光谱(Py-FTIR)实验结果显示,Fe增加了催化剂表面的Lewis酸性位。
Fe-Ag / Al 2 O 3 catalysts with different Fe / Ag loadings were prepared by sol-gel method and impregnation method using honeycomb ceramic as carrier. Using C_3H_6 as the reductant, the performance of catalytic reduction of NO was evaluated on a controlled temperature ceramic flow reactor under the condition of simulated flue gas and 200-700 ℃. The results showed that the denitrification efficiency of C_3H_6 reduction NO at 7.2% Fe and 1.9Ag / 20Al_2O_3 / CM at 500 and 550 ℃ was more than 90% and 100%, respectively. Iron ions can effectively improve the resistance of Ag / 20Al_2O_3 / CM catalysts to SO_2 and H_2O in flue gas. The results show that the denitrification efficiency of NO reduction with C_3H_6 catalyzed by 7.2Fe / 1.9Ag / 20Al_2O_3 / CM at 500 ℃ is unaffected when the flue gas contains SO2 with volume fraction of 0.02% and H_2O with 8% Continuous experiments to maintain 90% of the denitrification efficiency without decline. However, the catalytic activity of 2Ag / 20Al_2O_3 / CM without iron ion was greatly influenced by SO_2 and H_2O in the flue gas. 0.02% SO_2 and 8% H_2O respectively catalyzed the reaction of 2Ag / 20Al_2O_3 / CM at 500 ℃ for C_3H_6 The NO reduction efficiency of NO reduction decreased rapidly from 70% to 46% and 25% respectively. The results of XRD and SEM showed that AgFeO_2 and Fe ~ (3+) were formed on the surface of 7.2Fe / 1.9Ag / 20Al_2O_3 / CM catalyst modified by iron ions. The surface of the catalyst became porous and porous, forming Fe_3O_4-based needle Shape and flaky crystals. H_2-TPR results show that the 7.2Fe / 1.9Ag / 20Al_2O_3 / CM ratio Ag / 20Al_2O_3 / CM has better reduction characteristics in a wider temperature range. The results of Py-FTIR showed that Fe increased the Lewis acid sites on the catalyst surface.