Effect of Steam Treatment on the Catalytic Performance of ZSM-5 in the Co-conversion of Methanol and n-Hexane to Aromatics  

作　　者：Wei Shumei Xu Yarong Yang Fan Zhu Kake Zhu Xuedong 

机构地区：[1]State Key Laboratory of Chemical Engineering,School of Chemical Engineering,East China University of Science and Technology,Shanghai 200237,China [2]Research Institute of Urumqi Petrochemical Company,Petrochina,Urumqi 830019,China

出　　处：《China Petroleum Processing & Petrochemical Technology》2024年第3期73-81,共9页中国炼油与石油化工（英文版）

基　　金：We gratefully acknowledge financial support from the National Nature Science Foundation of China(2177606);PetroChina(Development of methanol coupled light hydrocarbon aromatization catalyst and process technology,2016A-24308).

摘　　要：Steam pretreatment is a widely used method for modifying the acidity and structure of zeolites,thereby enhancing their catalytic properties.This study systematically investigated the effects of steam treatment on ZSM-5 zeolites at varying treatment temperatures and durations.The structural evolution of the catalysts was monitored using N2 adsorptiondesorption,X-ray diffraction,inductively coupled plasma optical emission spectroscopy,scanning electron microscopy,NH3 temperature-programmed desorption,in situ pyridine infrared spectroscopy,and thermogravimetric analysis.The characterization results revealed that mesopores were introduced into the ZSM-5 zeolite catalysts through dealumination induced using steam treatment at moderate temperatures(400 and 500℃).Moreover,compared with the parent catalyst,the steam-treated catalysts exhibited a lower amount of acid sites and relative crystallinity,while the n(Si)/n(Al)ratio increased.In the co-conversion of methanol and n-hexane in a fixed bed reactor at 400℃and 0.5 MPa(N2 atmosphere),with a weight hourly space velocity of 1 h−1 and a stoichiometric ratio of 1:1(CH3OH to n-hexane),the steam-treated catalysts displayed a prolonged catalyst lifetime.Particularly,the parent zeolite had a lifetime of 96 h,while the catalyst treated at 500℃for 12 h had a lifetime of up to 240 h.Additionally,the steam-treated catalysts maintained stable n-hexane conversion and improved aromatic selectivity.Notably,these treated catalysts exhibited a lower deactivation rate than the parent catalyst,and would be conducive to industrial scale-up production.

关 键 词：steam ZSM-5 zeolites co-conversion AROMATIZATION METHANOL N-HEXANE 

分 类 号：TQ241[化学工程—有机化工] O643.36[理学—物理化学]