新型CeO2/HBEA催化剂上NH3低温还原NO活性及抗毒性能研究

采用等体积浸渍法制备了CeO2/HBEA催化剂,用于NH3选择性催化还原NO.考察了CeO2负载量、焙烧温度、氧浓度、空速、以及SO2和水蒸气等因素对催化剂活性的影响,并运用BET、X射线衍射(XRD)、扫描电镜(SEM)、热重分析(TGA)、傅里叶红外(FTIR)等手段对该催化剂进行表征,研究了催化剂的晶相、微观形貌与抗毒机制.结果显示:CeO2/HBEA催化剂具有良好的脱硝活性,高活性温度窗口在220～400℃,当反应温度为220℃、空速为12 000 h-1时,NO的转化率达96.49%.H2O的存在对催化剂的脱硝活性无明显影响.SO2一定程度抑制该催化剂的低温脱硝活性,但随着温度的升高,其脱硝活性得到一定恢复.所制备的CeO2/HBEA催化剂有良好的低温活性,能适应较高的空速,且具有较强的抗硫性和抗水中毒性能,有一定的应用前景.

Performance of a Novel CeO2/HBEA Catalyst for NO Reduction with NH3 and its property against the effect of H2O and SO2

The CeO2/HBEA catalyst was prepared by incipient wetness impregnation method.The effect of the CeO2 content,calcination temperature,oxygen concentration and space velocity on NO conversion were examined.The effect of SO2 and water vapor were also discussed.The means of BET,X-ray diffraction,SEM,TGA and FTIR were adopted to characterize the catalyst.CeO2 / HBEA catalyst exhibited high denitration activity at a temperature from 220 to 400 ℃,the NO conversion reached 96.5% at the condition of GHSV 12 000 h-1 and 220 ℃.The catalyst’s activity was little affected at the presence of H2O.To some extent,SO2 inhibited the catalytic activity at lower temperature,but the activity could be partly restored as temperature increased.Consequently,CeO2 / HBEA catalyst,had good application prospect owing to its good low-temperature activity,superior gas velocity flexibility,resistance to sulfur and water poisoning performance.