合成气直接制取二甲醚的双功能催化剂Ⅱ．脱水组分对催化剂性能影响的研究

Bifunctional catalysts for direct synthesis of dimethyl ether from synthesis gas Ⅱ. Study on the effect of dehydration components on catalyst properties

采用反应评价并结合ＸＲＤ、ＴＰＲ、吡啶－ＴＰＤ等物理化学手段研究了不同脱水组分对合成气直接制取二甲醚双功能催化剂结构和催化性能的影响，发现采用共沉淀沉积法制备的以ＣｕＯ－ＺｎＯ－Ａｌ２Ｏ３为甲醇合成活性组分、ＨＳＹ或ＨＺＳＭ－５Ａ分子筛为脱水组分的双功能催化剂表现出优良的催化性能：ＣＯ转化率达８９％，ＤＭＥ在有机物中的选择性接近９９％；此处还发现，双功能催化剂的两活性组分发生“协同效应”。

The effects of dehydration components on catalytic properties and the structures of bifunctional catalysts were investigated. Catalytic synthesis of dimethyl ether from synthesis gas was evaluated in a fixed bed flow microreactor at pressure 4.0 MPa, GHSV 1500h -1 characterization of the catalysts has been carried out using XRD、 TPR、 Pyridine TPD、 CO 2 TPD. The experimental results show that CuO ZnO Al 2O 3/HZSM 5 and CuO ZnO Al 2O 3/HSY catalysts exhibited the highest catalytic activity for direct synthesis of dimethyl ether from synthesis gas: conversion of CO is 89%, selectivity of DME (in organic compounds) is almost 99%. In addition, it indicates that the dehydration step of the reaction occurs in the weak acid sites and there is “synergistic effect” between the two kinds of active components of bifunctional catalysts.