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化学学报
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化学学报 ›› 2011, Vol. 69 ›› Issue (20): 2413-2419. 上一篇    下一篇

研究论文

Ga2O3/HZSM-5催化剂在乙烷脱氢反应中的积碳行为和MgO的修饰作用

俞超，秦枫，熊德胜，侯磊，沈伟*，徐华龙   

  1. (复旦大学化学系 上海市分子催化和功能材料重点实验室 复旦大学先进材料实验室 上海 200433)
  • 投稿日期:2011-01-25 修回日期:2011-05-10 发布日期:2011-06-10
  • 通讯作者: 沈伟 E-mail:wshen@fudan.edu.cn
  • 基金资助:

    上海市科学技术委员会基金

Coking and Modification of MgO on Ga2O3/HZSM-5 for Dehydrogenation of Ethane to Ethylene

YU Chao, QIN Feng, XIONG De-Sheng, HOU Lei, SHEN Wei, XU Hua-Long   

  1. (Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Laboratory of Advanced Materials, Fudan University, Shanghai 200433)
  • Received:2011-01-25 Revised:2011-05-10 Published:2011-06-10
  • Contact: Wei Shen E-mail:wshen@fudan.edu.cn

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研究了Ga2O3/HZSM-5催化剂在乙烷脱氢反应中的积碳、再生以及MgO的修饰作用. 通过激光拉曼、TG-MS和NH3-TPD等表征手段对反应过程的积碳种类和速率进行研究. 实验结果表明, 催化剂强酸中心上容易发生乙烷裂解生成甲烷的副反应并产生积碳, 其中石墨型积碳在反应过程中难以消除, 是导致催化剂失活的主要原因. MgO修饰可以减少催化剂强酸中心的量, 对乙烷裂解生成甲烷的副反应活性起到显著抑制作用, 并使积碳速率得到有效控制, 从而提高了催化剂的稳定性和乙烯的选择性. 催化剂再生时, 在空气气氛中加入水蒸气能够提高脱除石墨化碳的效率, 经420 ℃再生后催化剂的活性得到明显恢复.

关键词: Ga2O3/HZSM-5, 乙烷脱氢, 积碳, MgO修饰, 再生

Coking, decoking and modification of MgO on Ga2O3/HZSM-5 for dehydrogenation of ethane to ethylene are investigated by Laser Raman, TG-MS and NH3-TPD etc. The results demonstrate that coking and cracking of ethane can occur easily on the strong acidic sites. The formed graphitic coke is difficult to be removed in the reaction process, that is the main reason for deactivation of the catalyst. Modification of MgO can greatly reduce the amount of the strong acidic sites of the catalyst, which enhances the stability of the catalyst due to inhibiting the coking rate. Cracking of ethane is also greatly inhibited over MgO-Ga2O3/ HZSM-5 catalyst, and consequently the selectivity of ethylene is improved. Steam containing air atmosphere can improve the efficiency of decoking, especially for the graphitic coke. The catalytic activity is restored effectively under H2O-air flow at 420 ℃.

Key words: Ga2O3/HZSM-5, dehydrogenation of ethane, coking, modification of MgO, regeneration