Catalytic Performance and Coking Behavior of a Submicron HZSM-5 Zeolite in Ethanol Dehydration

• Published in: Chinese journal of chemistry Vol. 29; no. 7; pp. 1326 - 1334
• Main Author: 王飞 罗漫 肖文德
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.07.2011; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Subjects: alcohols; Coke; coking behavior; Dehydration; Ethanol; Gravimetric analysis; Low temperature; NMR; Nuclear magnetic resonance; Polycyclic aromatic hydrocarbons; precoking; Shells; submicron; Zeolites; 乙醇脱水; 亚微米; 催化性能; 反应温度; 沸石; 焦化; 行为; 预处理方法
• ISSN: 1001-604X; 1614-7065
• DOI: 10.1002/cjoc.201180250

The catalytic performance and coking behavior of a submicron ZSM-5 zeolite in dehydration of ethanol to ethylene were investigated by means of low temperature nitrogen adsorption, thermal gravimetric analysis, and nuclear magnetic resonance. The submicron catalyst showed higher activity than the micron one due to more mesopores and more strong acid sites. As the reaction temperature increased, ethanol conversion increased over the submicron catalyst, while ethylene selectivity went through a maximum. The selectivities of propylene and butylene increased with increasing reaction temperature, and they decreased with time on stream at constant temperature. The coke deposits can be divided into coke precursor and hard coke, which were attributed to polyalkylbenzene and poly- cyclic aromatic hydrocarbons, respectively; and increasing reaction temperature can accelerate the transformation of coke precursor into hard coke. A precoking pretreatment method was verified very effective for improving the catalyst stability.