TiO2/4A分子筛复合催化剂的制备及其乙醇脱水制乙烯性能
文献类型：学位论文
| ; | |
| 作者 | 肖妍艳 |
| 学位类别 | 硕士 |
| 答辩日期 | 2009-05-31 |
| 授予单位 | 中国科学院广州能源研究所 |
| 授予地点 | 广州能源研究所 |
| 导师 | 李新军 |
| 关键词 | TiO2/4A分子筛复合催化剂 改性 控制掺杂 乙醇脱水 乙烯 |
| 其他题名 | Preparation and catalytic dehydration of ethanol to ethylene of TiO2/4A zeolite composite catalysts |
| 中文摘要 | Ethylene is one of the most important intermediate chemicals. Nowadays, ethylene is conventionally produced by steam-cracking of petroleum. With the depletion of primary energy and the aggravation of environmental crisis, bio-ethanol has attracted more and more attention for ethylene production, and this route is recognized as a potential supplement for ethylene supply in the future. Catalyst plays a key role in the technology of ethanol dehydration to ethylene. TiO2/4A zeolite composite catalysts were prepared by coating TiO2 on 4A zeolite via liquid phase deposition, 4A zeolite/TiO2 composite catalysts were separately doped by Ce, Mn, Ce-Mn and Pt through impregnation method, and the TiO2/4A zeolite composite catalysts doped by Ni with nonuniform distribution were prepared by liquid phase deposition under process control. The catalysts were characterized by SEM, XRD, FTIR, BET, ICP and Pyridine-TPD, the catalytic performance of ethanol dehydration to ethylene of the catalysts was tested on a self-made fixed bed reactor, and the catalytic mechanism how TiO2 enhanced the catalytic performance was discussed. The results show that: 1. The optimal conditions for preparing TiO2/4A zeolite composite catalysts through liquid phase deposition were with 18 h deposition, 600 °C calcination and 400 ml deposition solution. In comparison with 4A zeolite, TiO2/4A zeolite composite catalysts exhibited weak surface acidity but much higher catalytic performance, especially the one with mixed TiO2 (A/R) showed best performance; 2. The 4A zeolite/TiO2 composite catalysts modified by Ce, Mn and Pt further promoted ethanol dehydration to ethylene, and the one modified by Ce-Mn exhibited best catalytic performance; 3. Among the TiO2/4A zeolite composite catalysts controllable doped by Ni with nonuniform distribution, the one with surface doped Ni exhibited best catalytic performance, and the optimal doping amount was 1.0%; 4. Based on the catalytic performance and Pyridine-TPD results of the catalysts, it is suggested that the catalytic performance of the catalysts is consistent with the effective Lewis acidity rather than the total acidity. The coated TiO2 might cause the changes of composite catalysts in two aspects. Physically, TiO2 might cover the surface acidic sites of 4A zeolite. Chemically, TiO2 might accept the thermal-induced electrons from 4A zeolite so as to increase the net Lewis acidity of composite catalysts, and consequently enhanced catalytic performance. The 4A zeolite/TiO2 composite catalysts modified by Ce, Mn and Pt further improved the catalytic performance might due to the increased oxygen vacancies promoted the net Lewis acidity. The TiO2/4A zeolite composite catalyst with surface doped Ni might form P-N junction so as to enhance the net Lewis acidity. |
| 语种 | 中文 |
| 公开日期 | 2011-07-10 ; 2011-07-15 |
| 页码 | 75 |
| 源URL | [http://ir.giec.ac.cn/handle/344007/4037]  |
| 专题 | 中国科学院广州能源研究所 |
| 推荐引用方式 GB/T 7714 | 肖妍艳. TiO2/4A分子筛复合催化剂的制备及其乙醇脱水制乙烯性能, Preparation and catalytic dehydration of ethanol to ethylene of TiO2/4A zeolite composite catalysts[D]. 广州能源研究所. 中国科学院广州能源研究所. 2009. |
入库方式： OAI收割
来源：广州能源研究所
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