含水蒸气烧炭再生对β沸石催化剂脱铝的影响  

Influence of Coke-Burning Regeneration Using Steam-Containing Air Flow on Dealumination of β Zeolite Catalyst

作　　者：傅吉全[1] 曹廷炳[1] 

机构地区：[1]北京服装学院化工所北京市重点实验室,北京100029

出　　处：《催化学报》2003年第11期811-815,共5页

摘　　要：以苯与丙烯的烷基化反应中试失活 β沸石催化剂为研究对象 ,在水蒸气存在下进行烧炭再生 ,着重考察了温度对催化剂脱铝的影响 ,并揭示出脱铝影响催化剂的活性、酸性、晶体结构和孔结构特征 .用滴定法及核磁共振法确定了新鲜催化剂和再生催化剂骨架的硅 /铝比 ,并结合XRD表征阐明在高于 450℃下烧炭再生时确有脱铝发生 .控制再生温度可使催化剂性能基本得到恢复 .寿命实验结果表明 ,含水蒸气再生后的样品与新鲜催化剂有相当的寿命 ,该方法可用于失活催化剂的再生 .提出了水蒸气存在下能有效控制烧炭反应 。The regeneration of β zeolite catalyst, used in alkylation of benzene with prop ylene in a middle-scale unit, was carried out in-situ by coke-burning met hod using steam-air flow ( V(air) / V(steam) =1). The temperature in the catalyst bed was run away in the regeneration proces s when φ(O 2) =10% in the air flow. When φ(O 2) was lower, although the temperature rise in the bed was controlled, the decoking rate was very low so that the regeneration cycle had to take a long pe riod. The influence of the regeneration conditions on the activity, acidity, pore structure and framework dealumination of the β zeolite catalyst was inves tigated. The acidity and coke cont ent of β zeolite were measured by temperature-programmed desorption and temperature programmed oxidation. The crystal property and pore structure of the catalyst were characterized by XRD and pore structure characterization device r e spectively. The total Al content and framework n(Si) / n(Al) ratio were defined by chemical titration and solid-state MAS N MR. The experiments of accelerating aging for fresh and regenerated samples und er the same condition were carried out to prove the feasibility of the regenerat ion process. The results indicated that the framework dealumination of the sampl e s occurred when the regeneration temperature was higher than 450 ℃, while the activity of the catalyst could be recovered if the temperature was controlled pr operly. The results of accelerated-aging experiments showed an equivalent life time for both fresh and regenerated samples. Between 350 and 550 ℃, both framew ork dealumination and decoking amount were increased with increasing the regene rati on temperature, while the activity, the number of acid sites and the pore struct ure property of the samples showed an extreme value respectively. The activity and the acid sites could be recovered almost completely, and there was no frame w ork dealumination at 450 ℃. The best pore structure property was obtained at 55 0 ℃. T

关 键 词：Β沸石 水蒸气 烧炭 再生 脱铝 苯 丙烯 烷基化 异丙苯 

分 类 号：O643.3[理学—物理化学]