Effect of nickel incorporation on the acidity and stability of HZSM-5 zeolite in the MTO process
Effect of nickel incorporation on the acidity and stability of HZSM-5 zeolite in the MTO process
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DOI：
10.1016/j.cattod.2005.07.132
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发表时间：
2005-10
期刊：
影响因子：
5.3
通讯作者：
Beatriz Valle;A. Alonso;A. Atutxa;A. Gayubo;J. Bilbao
中科院分区：
文献类型：
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作者：
Beatriz Valle;A. Alonso;A. Atutxa;A. Gayubo;J. Bilbao
研究了Ni掺入对酸度（酸强度分布和总酸度）、对HZSM-5沸石的水热稳定性和对该催化剂在高温（高达500 ℃，以提高烯烃选择性）和当进料中存在高水含量时（以使焦炭失活最小化）在MTO工艺中的动力学性能的影响。在HZSM-5沸石中引入Ni意味着沸石的总酸度和酸强度的降低，因此，催化剂的活性降低。然而，具有Ni的催化剂比母体沸石催化剂更水热稳定。约1wt%的Ni含量是最佳的，因为它允许在反应-再生循环中不间断地操作，介质中的水含量高于50wt%，而没有不可逆的失活，而较高的Ni含量产生不必要的初始活性损失。
A study has been carried on the effect of Ni incorporation on the acidity (acid strength distribution and total acidity), on the hydrothermal stability of a HZSM-5 zeolite and on the kinetic performance of this catalyst in the MTO process at high temperature (up to 500°C, in order to increase selectivity to olefins) and when there is a high water content in the feed (in order to minimise deactivation by coke). The incorporation of Ni in the HZSM-5 zeolite implies a decrease in the total acidity and in the acid strength of the zeolite and, consequently, the activity of the catalyst decreases. Nevertheless, the catalysts with Ni are hydrothermally more stable than the parent zeolite catalyst. A Ni content around 1wt% is the optimum, as it allows for uninterrupted operation in reaction–regeneration cycles, with water contents higher than 50wt% in the medium, without irreversible deactivation, whereas a higher Ni content produces an unnecessary loss of initial activity.