Aromatization of n-Butane and i-Butane over PtSnK/ZSM-5 Catalysts: Influence of SiO2/Al2O3 Ratio
Aromatization of n-Butane and i-Butane over PtSnK/ZSM-5 Catalysts: Influence of SiO2/Al2O3 Ratio
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PtSnK/ZSM-5 催化剂上正丁烷和异丁烷的芳构化：SiO2/Al2O3 比例的影响
DOI：
10.1007/s10562-018-2548-4
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发表时间：
2018
影响因子：
2.8
通讯作者：
Fang Weiping
中科院分区：
文献类型：
--
作者：
Yang Kang;Yin Yanbo;Lai Shengsong;Zhu Lingting;Zhang Jie;Lai Weikun;Lian Yixin;Fang Weiping
研究了在丁烷芳构化过程中，SiO_2/Al_2O_3摩尔比分别为25、38、50和80对PtSnK/ZSM-5催化剂物化性能和催化性能的影响。结果表明，随着SiO_2/Al_2O_3的增加，铂的分散度明显减小。酸性中心的强度和类型相似，但氧化还原性能受到显著影响。H2-TPD分析表明，除PtSnK/ZSM-5-80外，均生成了具有大的分离的铂系综外的铂-SnOx物种。PtSnK/ZSM-5-50催化剂的共进料(混合丁烷：50wt%正丁烷 + 50wt%异丁烷)转化率(88%)和较低的铂分散度(25%)得到了改善。此外，当苯/C8芳烃和甲烷/丙烷的摩尔比都较高时，由于外接触时间较短，在PtSnK/ZSM-5-50催化剂上，混合丁烷在铂-SnOx上的脱氢更有利。因此，SiO_2/Al_2O_3比对芳烃分布的影响主要与铂的分散和分布的不同有关。然而，生产轻芳烃(BTX)的主要过程仍然是氢转移，这有助于延长寿命。
This work reports on the effect of SiO2/Al2O3 ratio (25, 38, 50 and 80) on the physicochemical properties and performance of PtSnK/ZSM-5 catalysts in butanes aromatization process. It was found that the Pt dispersion decreased obviously with SiO2/Al2O3 increasing. The strength and type of acid sites look similar, while the redox properties were influenced significantly. The Pt–SnOx species are produced except for PtSnK/ZSM-5-80 with large separated Pt ensembles from H2-TPD analysis. The PtSnK/ZSM-5-50 catalyst shows the improved cofeeding (mixed butanes: 50 wt% n-butane + 50 wt% i-butane) conversion (88%) with lower Pt dispersion (25%). Furthermore, dehydrogenation of mixed butanes over Pt–SnOx is more favorable on PtSnK/ZSM-5-50 when both ratios of benzene/C8 aromatics and methane/propane are high, due to the outside contact time is short. So the influence of SiO2/Al2O3 ratio on the aromatics distribution is mainly related to the difference in the Pt dispersion and distribution. However, the predominate process to produce light aromatics (BTX) is still hydrogen transfer, which contributes to the long-life span.Graphical Abstract