Co/Fe/Al2O3/cordierite催化C3H6选择性还原NO的实验研究

采用溶胶凝胶法和浸渍法制备了负载于蜂窝陶瓷上的Co/Fe/Al₂O₃/cordierite催化剂，在陶瓷管流动反应器上对其催化C₃H₆选择性还原NO的性能进行了测试。结果表明，该催化剂表现出最优脱硝性能，在模拟烟气条件下，当反应温度为550 ℃时可实现97%的脱硝效率。Co的引入可显著增强Fe/Al₂O₃/cordierite催化剂抗SO₂和H₂O的能力。在模拟烟气中同时引入0.02% SO₂和3% H₂O后，1.5Co/Fe/Al₂O₃/cordierite的脱硝性能受影响甚微，当反应温度高于500 ℃时1.5Co/Fe/Al₂O₃/cordierite催化C₃H₆还原NO的效率均可达到90%以上；相比之下，未经Co修饰的催化剂Fe/Al₂O₃/cordierite脱硝性能受到了严重的抑制，在整个反应温度区间（200-700 ℃）内，其催化C₃H₆还原NO的效率最高不足50%。XRD和SEM表征结果表明，经过适量的Co修饰后的1.5Co/Fe/Al₂O₃/cordierite表面变得更疏松，且形成了以钴铁和钴铝双金属氧化物为主要成分的球状晶粒。H₂-TPR结果表明，相比于Fe/Al₂O₃/cordierite，1.5Co/Fe/Al₂O₃/cordierite有更好的低温还原性能。Py-FTIR结果表明，Co的引入可使催化剂表面的Lewis酸明显增加，且生成了Brønsted酸。N₂吸附-脱附表征结果表明，Co可增大催化剂的比表面积。

Experimental study on the selective catalytic reduction of NO with C3H6 over Co/Fe/Al2O3/cordierite catalysts

The Co/Fe/Al₂O₃/cordierite catalysts with different Co loadings were prepared by sol-gel and impregnation methods, and their performance in the selective catalytic reduction of NO with C₃H₆ over catalytic were experimentally studied in a ceramic tubular reactor. The results indicated that 1.5Co/Fe/Al₂O₃/cordierite showed the highest C₃H₆-SCR activity with 97% NO reduction in the simulated flue gas at 550 ℃. Cobalt was able to effectively improve the ability of Fe/Al₂O₃/cordierite catalysts to resist SO₂ and H₂O in flue gas. When 0.02% SO₂ and 3% water vapor were added to the simulated flue gas, the NO reduction efficiency of 1.5Co/Fe/Al₂O₃/cordierite was almost unaffected, the NO reduction by 1.5Co/Fe/Al₂O₃/cordierite with C₃H₆ all surpassed 90%. In contrast, the catalytic activity of Fe/Al₂O₃/cordierite without cobalt modification was seriously suppressed by SO₂ and H₂O, the highest NO reduction efficiency of Fe/Al₂O₃/cordierite was less than 50% within the entire reaction temperature range (200-700 ℃).XRD and SEM results showed that the surface of 1.5Co/Fe/Al₂O₃/cordierite after the modification by cobalt became loose, and formed by the cobalt iron and cobalt aluminum metal oxide-based spherical grains.H₂-TPR results showed that 1.5Co/Fe/Al₂O₃/cordierite had better low temperature reduction performance than Fe/Al₂O₃/cordierite. Py-FTIR results confirmed that Co can dramatically increased the Lewis acid and produced Brønsted acid on the catalyst surface. N₂ adsorption/desorption characterization results proved that Co can increase the specific surface area of the catalyst.