基于不同Cu-CHA催化剂方案的NH_(3)-SCR性能及氨存储特性研究  

Research on NH_(3)-SCR performance and ammonia storage characteris-tics based on different Cu-CHA catalyst schemes

作　　者：赖慧龙 于飞 杨冬霞 马江丽 殷雪梅 常仕英 LAI Huilong;YU fei;YANG Dongxia;MA Jiangli;YIN Xuemei;CHANG Shiying(Sino-Platinum Metals Catalyst(Dongying)Co.,Ltd.,Dongying 257029,China;R&D Department,Kunming Sino-Platinum Metals Catalyst Co.,Ltd.,Kunming 650101,China)

机构地区：[1]贵研催化剂(东营)有限公司,山东东营257029 [2]昆明贵研催化剂有限责任公司技术研究院,云南昆明650101

出　　处：《无机盐工业》2024年第12期159-166,共8页Inorganic Chemicals Industry

基　　金：山东省重点研发计划项目(2022CXGC020311);云南省科技人才与平台计划项目(202305AD160018、202305AF150109);云南省重大科技专项计划项目(202402AC080004)。

摘　　要：为研究选择性催化还原(SCR)催化剂涂层硅铝比(SAR)、负载量、载体目数及氨/氮氧化物的物质的量比(ANR)对瞬态NO_(x)转化率及氨存储特性的影响,采用离子交换法制备SAR为12、22的Cu-CHA涂层,结合140、160 g/L负载量,62、93个孔/cm^(2)目数载体制备出4种涂覆式催化剂。通过NH_(3)-TPD/H_(2)-TPR表征材料发现,SAR为12的涂层具备更多活性Cu^(2+)和更多酸性位点。采用固定床反应器和发动机台架分别研究SCR瞬态单点性能和工况排放。单点性能研究发现,各方案低温NO_(x)反应速率由高到低的顺序依次为12-160-93、12-160-62、12-140-62、22-160-62,12-160-93方案下180、200、250℃单点平均反应速率分别可达2.24×10^(-6)、4.37×10^(-6)、1.48×10^(-5)mol/s;低SAR、高负载量、高载体目数方案都会提升单点瞬态NO_(x)转化率,降低瞬态氨存储量,提升ANR可同时提升瞬态NO_(x)转化率和瞬态氨存储量。各方案下工况NO_(x)排放与低温单点性能一致,但是高负载方案增加了变化工况下NH_(3)泄漏量,与单点NH_(3)泄漏趋势相反。To investigate the effects of coating silicon aluminum ratio(SAR),loading amount,cell density of substrate scheme,and ammonia/nitrogen oxide molar ratio(ANR)on transient NOx conversion efficiency and ammonia storage characteristics of SCR catalysts,Cu-CHA coatings with SAR=12 and 22 were prepared by ion exchange method.Four coating catalyst schemes were prepared by combining loading amounts of 140 g/L and 160 g/L,62 pores/cm2 and 93 pores/cm^(2)mesh size carriers.Through NH_(3)-TPD/H2-TPR characterization of the material,it was found that the SAR=12 coating had more active Cu^(2+)and more acidic sites.The transient single point performance and operating condition emissions of SCR were studied using a fixed bed reactor and an engine bench,respectively.Single point performance studies showed that the low-temperature NOx reaction rates of each scheme were 12-160-93,12-160-62,12-140-62,22-160-62.Under the 12-160-93 scheme,the average single point reaction rates at 180℃,200℃,and 250℃could reach 2.24×10^(-6)mol/s,4.37×10^(-6)mol/s and 1.48×10^(-5)mol/s,respectively.Low SAR,high load,and high cell density schemes could improve the transient NOx conversion rate at a single point,reduce the transient ammonia storage capacity.Improving ANR could simultaneously enhance transient NOx conversion rate and transient ammonia storage capacity.The NOx emissions under different operating conditions were consistent with the lowtemperature single point performance,but the high load scheme enhanced the NH_(3)leakage under changing operating conditions,which was opposite to the trend of NH_(3)leakage at a single point performance.

关 键 词：Cu-CHA型分子筛 选择催化还原 NOx反应速率 氨存储特性 氨泄漏 

分 类 号：TQ131.21[化学工程—无机化工]