稀土元素对钒基SCR脱硝催化剂的改性研究  

Modification of Rare Earth Elements to Vanadium Based SCR Catalyst

作　　者：莫建益 吴鹏[2] 眭华军 丰国林 张亚平[2] MO Jianyi;WU Peng;GUI Huajun;FENG Guolin;ZHANG Yaping(Jianbi Power Plant,Zhenjiang 212006,China;Key Laboratory for Energy Thermal Conversion and Control of Ministry of Education,Southeast University,Nanjing 210096,China)

机构地区：[1]谏壁发电厂,江苏镇江212006 [2]东南大学,能源热转换及其过程测控教育部重点实验室,江苏南京210096

出　　处：《环境科学与技术》2020年第11期90-95,共6页Environmental Science & Technology

基　　金：国家重点研发计划(2017YFB0603201)。

摘　　要：近年来,电力行业产能过剩及燃煤电厂参与电网深度调峰,燃煤机组负荷持续较低,导致常规SCR脱硝催化剂难以满足环保排放要求,有效拓宽催化剂活性温度窗口迫在眉睫。该文通过浸渍Ho、Ce、Sb制备了一系列V_(2.5)W_(5)M_(x)/TiO_(2)催化剂,并通过BET、XRD、XRF、H2-TPR、NH3-TPD和In-situ DRIFTS表征技术对改性机理进行了探究。结果显示,Ce和Sb具有较好的改性作用,其中V2.5W5Ce4/TiO_(2)和V2.5W5Sb4/TiO_(2)催化剂对NOx的转化率在220℃时接近95%,在260~380℃宽温度范围内进一步达到100%,且具有优异的选择性和抗H2O性能。表征结果显示,适量的Ho、Ce和Sb的加入有效削弱了TiO_(2)的结晶度,且催化剂载体表面上金属氧化物组分分散均匀。TPR、TPD和原位DRIFTS结果显示,改性后的催化剂的氧化还原性能和表面酸性显著增强,是催化剂低温活性提高的重要原因。In recent years,the overcapacity of the power industry and the participation of coal-fired power plants in the power grid’s deep peak shaving have led to continuous low load of coal-fired units.Conventional SCR catalysts are difficult to meet environmental emission requirements.Therefore,it is extremely urgent to effectively broaden the catalyst activity temperature window.In this paper,a series of V2.5 W5 Mx/TiO_(2)catalysts were prepared by impregnating Ho,Ce,Sb on TiO_(2),and the modification mechanism was analyzed by BET,XRD,XRF,H2-TPR,NH3-TPD and in-situ DRIFTS characterization techniques.The results show that Ce and Sb have better modification effects.The NOxconversion rate of V2.5 W5 Ce4/TiO_(2)and V2.5 W5 Sb4/TiO_(2)catalysts is close to 95%at 220℃,and further reaches 100%in a wide temperature range of 260~380℃,accompanied by excellent selectivity and H2 O resistance.The characterization results revealed that the addition of an appropriate amount of Ho,Ce and Sb effectively weakened the crystallinity of TiO_(2),and the metal oxide components on the surface of the catalyst support were evenly dispersed.The results of TPR,TPD and in-situ DRIFTS confirmed that the redox performance and surface acidity of the modified catalyst were significantly enhanced,which is an important reason for the improvement of low temperature catalytic activity.

关 键 词：选择性催化还原 低温 脱硝 稀土元素 

分 类 号：X511[环境科学与工程—环境工程]