废弃选择性催化还原催化剂混掺对新催化剂脱硝性能的影响

摘要

A series of catalyst samples with different spent catalyst mass ratio were prepared for de-NOxactivity tests and life time evaluation experiments on a home-made experiment system.The results indicated that,when the spent catalyst mass ratio was below 5%,the de-NOxefficiency was slightly lower than that of the sample without spent catalyst.However,when the spent catalyst mass ratio was increased to 10%,the de-NOxactivity declined rapidly.The catalyst samples were characterized with N2adsorption-desorption,scanning electron microscopy(SEM),X-ray fluorescence (XRF)and X-ray diffraction(XRD)analysis.The results showed that the alkali metal and As oxide from the spent catalyst could poison the samples,leading to lower de-NOxactivity.In addition,the surface complexity of 15-cat was much lower than that of 0-cat,which resulted in less BET surface.The tests indicated that the de-NOxactivity would be restrained under high mass ratio of spent catalyst.%采用"混炼-挤出-干燥-煅烧"工艺制备了不同废弃选择性催化还原(SCR)催化剂混掺比例的新催化剂样品,在自制实验台架上进行了脱硝性能和脱硝寿命评估实验.实验表明,当废催化剂混掺比例小于5%时,样品脱硝性能相比无混掺样品有轻微下降,催化剂脱硝效率随运行时间的衰减速率正常;当混掺比例大于5%时,催化剂样品脱硝性能大幅衰减,催化剂寿命缩短.结合N2吸附-脱附、扫描电子显微镜(SEM)、X射线荧光光谱(XRF)、X射线衍射(XRD)等表征手段分析,废催化剂的掺入会将碱金属、As等有害物质带入到高混掺量的样品中,导致催化剂脱硝性能下降;混掺比例高达15%时,15-cat样品表面复杂程度大幅下降,不利于SCR反应进行.实验论证了较高废弃催化剂混掺比例会严重影响制备所得新催化剂的脱硝性能.