离子交换法改性ZSM-5的NH_3-SCR性能研究

NH_3-SCR activity of modified ZSM-5 prepared by aqueous ion-exchange method

为了获得可以在低温条件下具有较高脱硝效率并且无毒易得的SCR催化剂,采用了传统水溶液离子交换法制备Cu-ZSM-5,Ce-ZSM-5催化剂和连续水溶液离子交换法制备Cu-Ce-ZSM-5,Ce-Cu-ZSM-5催化剂,并运用N_2吸附脱附、扫描电镜、X射线衍射对吸附催化剂进行物理化学表征。在100—500℃温度范围,空速60 000 h^(-1)的条件下进行SCR活性测试。结果表明,Cu-ZSM-5,Cu-Ce-ZSM-5和Ce-Cu-ZSM-5催化剂表现出了良好的低温活性,在200—300℃范围内脱硝效率接近100%,而在100—200℃范围内Cu-ZSM-5催化剂的SCR活性最高。改性ZSM-5催化剂与传统SCR催化剂相比拥有无毒易得、低温活性好等优点,具有广泛的工业应用前景。

In order to obtain accessible and non-toxic SCR catalysts,Cu-ZSM-5 and Ce-ZSM-5 were prepared by conventional aqueous ion-exchange method, Cu-Ce-ZSM-5 and Ce-Cu-ZSM-5 were prepared by means of subsequent aqueous ion-exchange method. Modified ZSM-5 catalysts were characterized using nitrogen physisorption,scanning electron microscopy（ SEM）,X-ray diffraction（ XRD）. The SCR performance on catalysts were investigated at 100 ℃ to 500 ℃ corresponding to a gas hourly space velocity（ GHSV） of 60 000 h^-1. The results suggested that Cu-ZSM-5,Cu-Ce-ZSM-5 and Ce-Cu-ZSM-5 catalysts showed good low temperature activity.What＇s more,the NO conversion was close to 100% at 200 ℃ to 300 ℃. And the SCR activity of Cu-ZSM-5 was the highest from 100 ℃ to 200 ℃. Compared with traditional SCR catalysts,modified ZSM-5 catalysts have several advantages such as non-toxic,cheap and good low temperature SCR activity,which show extensive industry application prospects.