摘要
在固定床反应器中考察了乙醇脱水反应中亚微米ZSM-5分子筛催化剂的预处理及积炭行为,采用热重(TG)、低温氮吸附、X射线荧光光谱(XRF)、X射线衍射(XRD)和核磁共振(NMR)等方法对催化剂进行表征。结果表明,催化剂在使用前活化时的焙烧温度以550℃为宜。催化剂在水蒸气预处理后,初始活性升高。随着质量空速的升高,初始乙醇转化率和乙烯选择性以及积炭量均有所降低;但质量空速过低时,催化剂活性降低很明显。原料乙醇中的水能降低催化剂的积炭量和积炭的不饱和度,可使催化剂脱铝增加约5%。随着催化剂颗粒粒径的减小,催化剂的活性增高,在粒径约为0.4 mm时,积炭量较低。
The pretreatment and coking behavior of a submicron ZSM-5 catalyst during ethanol dehydration was invetigated in a fix-bed reactor by means of thermogravimetric analysis（TG-DTG）,N2 adsorption techniques,X-ray diffraction（XRD） and nuclear magnetic resonance（NMR）.The experimental results showed that the appropriate calcination temeprature for calayst was 550 ℃.The initial activity of catalyst was improved by steam treatment.The initial conversion of ethanol and selectivity of ethylene and coke amount decreased with the increase of weight hourly space velocity.But when the weight hourly space velocity was too low,the activity of catalyst would quickly decrease.Water in the feedstock could decrease the coke deposits and alleviate the evolution of coke deposits,but it resulted in serious dealumination.The activity of catalyst increased with the decrease of catalyst particle size,while the coke amount was lower when the catalyst particle size was about 0.4 mm.
出处
《化学反应工程与工艺》
CAS
CSCD
北大核心
2010年第6期500-508,共9页
Chemical Reaction Engineering and Technology
