文献类型：期刊文献

英文题名：Effect of Modified Zeolite on One-Step Process of DME Synthesis

作者：Xu, Q. -L.[1];Lan, P.[2];Zhang, S. -P.[1];Li, T. -C.[1];Yan, Y. -J.[1]

机构：[1]E China Univ Sci & Technol, Res Ctr Biomass Energy, Shanghai 200237, Peoples R China;[2]Guangxi Univ Nationalities, Sch Chem & Ecoengn, Guangxi, Peoples R China

年份：2011

卷号：29

期号：5

起止页码：439

外文期刊名：PETROLEUM SCIENCE AND TECHNOLOGY

收录：;EI(收录号：20110413616258);WOS:【SCI-EXPANDED(收录号:WOS:000286818000001)】；

语种：英文

外文关键词：bifunctional catalyst; CaO; DME; MgO; zeolite HZSM-5; ZnO

摘要：HZSM-5 zeolites modified by MgO, CaO, and ZnO were prepared by impregnation and bifunctional catalysts were prepared by modified HZSM-5 zeolites and JC207 catalyst (a catalyst for methanol synthesis, which has been industrialized in China). Evaluation of catalytic activity was conducted in a fixed-bed reactor. Results show, with proper basic oxide-modified zeolite, a Bronsted acid site (strong acid sites) shift to Lewis acid site (weak acid sites). Weak and less strong acid sites on HZSM-5 zeolite are activity centers for the formation of dimethyl ether (DME), whereas strong acid sites for by products such as hydrocarbons. Consequently, the selectivity of CO2 and hydrocarbons decrease, especially with zeolite modified by CaO.