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›› 2007, Vol. 7 ›› Issue (3): 490-495.

• 反应与分离 • 上一篇    下一篇

Zn与Mn复合改性HZSM-5催化低浓度乙醇脱水制乙烯

潘锋,吴玉龙,张建安,杨明德,刘德华,童军茂   

  1. 新疆石河子大学食品学院
  • 出版日期:2007-06-20 发布日期:2007-06-20

Ethanol Dehydration to Ethylene over HZSM-5 Catalyst Modified by Zn and Mn

PAN Feng,WU Yu-long,ZHANG Jian-an,YANG Ming-de,LIU De-hua,DONG Jun-mao   

  1. Food College, Shihezi University
  • Online:2007-06-20 Published:2007-06-20

摘要: 对浸渍法锌锰复合改性HZSM-5分子筛用于催化低浓度乙醇脱水制备乙烯进行了研究. 探讨了改性溶液类型、HZSM-5原粉硅/铝比和改性条件(改性溶液浓度、浸渍时间、浸渍温度、焙烧温度)对Zn/Mn/ZSM-5催化乙醇脱水效果的影响,通过XRD、孔体积与比表面积、微观形貌分析等方法对改性前后的HZSM-5进行了表征. 结果表明,当HZSM-5原粉硅/铝比为25,改性温度为40℃, Zn(NO3)2和MnCl2浓度分别为2%和6%条件下改性1 h,再于550℃焙烧获得的分子筛催化效果最好,乙醇转化率和乙烯选择性分别达到99%和92%以上. 表征结果表明,Zn2+和Mn2+进入了分子筛骨架中,分子筛能很好地保持原有的结构,并且B酸中心量减少,L酸中心量增多,这有利于乙醇催化脱水制乙烯.

关键词: HZSM-5, 改性, 乙醇, 脱水, 乙烯

Abstract: Preparation of ethylene from ethanol dehydration catalyzed by HZSM-5 molecular sieve modified with Zn and Mn was studied. The effects of modified solution, Si/Al ratio of HZSM-5, and modified conditions, such as concentration of modified solution, modification reaction time and temperature, and calcination temperature, were investigated. The results showed that when the Si/Al ratio of ZSM-5 was 25, modification temperature was 40℃, the concentrations of Zn(NO3)2 and MnCl2 were 2% and 6% respectively, the modification time was 1 h, and the calcination temperature was 550℃, the catalytic activity of modified HZSM-5 was higher. The HZSM-5 and modified ZSM-5 were characterized by XRD, BET, SEM and FT-IR techniques. The result indicated that Zn2+ and Mn2+ were located in the zeolite frame, and the crystalline structure of the modified zeolites was not changed, in addition B acid sites were decreased slightly and L acid sites increased greatly, which were favorable to catalytic dehydration of ethanol to ethylene.

Key words: HZSM-5, modification, ethanol, dehydration, ethylene