摘要
轻烃芳构化产物选择性调控是芳构化催化剂研究的热点和难点.本文以Mg为调控元素考察了HZSM-5沸石酸性及孔道空间大小调控对丙烷芳构化产物选择性的影响.分别采用沸石骨架改性和初湿浸渍法改性法制备了Mg@ZSM-5和Mg/ZSM-5样品并用作丙烷芳构化催化剂.结果表明,Mg物种的不同改性方式对其Mg分布、酸性和孔结构方面产生较大影响.原位合成引入Mg物种后Mg物种均匀分布在催化剂中,Mg@ZSM-5沸石的总酸、B和L酸含量与未改性的HZSM-5比均上升,但是B/L值会显著降低.浸渍法制备的Mg/ZSM-5样品MgO以表面和浅层分布为主,与未改性HZSM-5相比,消除大量B酸位点,同时有效增加了L酸位点分布,整体酸量保持不变.两种含Mg沸石的总孔体积较HZSM-5样品相比均有所下降,孔体积下降使得芳烃产物分布中提升了BTX选择性.沸石B/L值的下降是导致丙烷转化率下降的原因.该酸性的变化还导致与HZSM-5比,Mg@ZSM-5和Mg/ZSM-5催化丙烷芳构化反应时,丙烷的活化温度和芳烃的生成温度均有明显提升.
Selective regulation of light hydrocarbon aromatization products is a hot and difficult topic in the research of aromatization catalysts.This article investigates the effects of acidity and pore space control on the selectivity of propane aromatization products in HZSM-5 zeolite using Mg as a regulating element.The samples were prepared by using zeolite framework modification and incipient wetness impregnation methods,respectively,Mg@ZSM-5 and Mg/ZSM-5 samples were obtained and used as a catalyst for propane aromatization.The results indicate that different modification methods have a significant impact on their Mg distribution,acidity,and pore structure.After introducing Mg species through in-situ synthesis,the Mg species were uniformly distributed in the catalyst,the total acid,B and L acid content of Mg@ZSM-5 zeolite increased compared to unmodified HZSM-5,but the B/L value significantly decreased.The Mg/ZSM-5 sample prepared by impregnation method mainly has surface and shallow distribution of MgO,compared with unmodified HZSM-5,it eliminates a large number of B acid sites and effectively increases the amount of L acid sites,while the overall acid content remains unchanged.It is found that total pore volume of both Mg containing zeolites decreased compared to the HZSM-5 sample,and the decrease in pore volume improved the BTX selectivity in the distribution of aromatic products.The results also indicate that the decrease in zeolite B/L ratio is the reason for the decrease in propane conversion rate.The change in acidity also leads an obvious change to the aromatization reaction temperature,compared with HZSM-5,both the propane activation temperature and aromatization temperature of Mg@ZSM-5 and Mg/ZSM-5 increased.
作者
马跃
黄羚翔
檀宇航
安海涛
张强
曾鹏晖
朱小春
申宝剑
MA Yue;HUANG Lingxiang;TAN Yuhang;AN Haitao;ZHANG Qiang;ZENG Penghui;ZHU Xiaochun;SHEN Baojian(State Key Laboratory of Heavy Oil Processing,College of Chemical Engineering and Environment,China University of Petroleum,Beijing 102249,China)
出处
《分子催化(中英文)》
北大核心
2025年第2期141-153,I0002,I0003,共15页
Journal of Molecular Catalysis(China)
基金
国家自然科学基金创新研究群体项目(22021004)
国家自然科学基金面上项目(21776304)。
