Kinetics study and analysis of zeolite Y destruction

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• 作者：Xiaohui Du ; Xueli Li ; Haitao Zhang ; Xionghou Gao ; ^{gaoxionghou@petrochina.com.cn" class="auth_mail" title="E-mail the corresponding author} ; ^{swingdu@163.com" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Y zeolite ; Vanadium ; Sodium ; Rare earth ; Hydrothermal stability ; Destruction ; Apparent activation energy
• 刊名：Chinese Journal of Catalysis
• 出版年：2016
• 出版时间：February 2016
• 年：2016
• 卷：37
• 期：2
• 页码：316-323
• 全文大小：825 K

文摘

A series of zeolites, including USY zeolites without sodium, Na-USY at different Na contents, La-USY with different rare earth (RE) contents and La-Na-USY with RE and Na were prepared by an ion exchange method. They were investigated to understand the activation barriers for the destruction of Y zeolite structure under hydrothermal treatment and the effect of V using the solid-state kinetic model. The results showed that the pathways for Y zeolite destruction were dealumination, desiliconization and the disappearance of La–O bonds. Zeolites were destroyed by steam through acid hydrolysis, which was accelerated by V. In addition, Na and V exerted a synergistic effect on the framework destruction, and the formation of NaOH was the rate-determining step. The presence of RE elements decreased hydrolysis and stabilized the structure of the zeolites. The interaction between V and RE destroyed zeolite structure by eliminating the stabilizing La–O [RE–OH–RE]⁵⁺ bridges in the sodalite cages.