CO_2加氢合成二甲醚催化剂双组份复合方法研究

Mixing methods of the bifunctional catalyst for dimethyl ether synthesis from CO_2 hydrogenation

采用悬浮并流、湿混和干混的方法制备CuO-ZnO-Al2O3/HZSM-5双功能催化剂。考察了不同混合方法对催化剂催化性能的影响。结果表明,采用悬浮液并流共沉淀法制备的双功能催化剂,对CO2加氢直接合成二甲醚有较高的催化性能:在固定床反应器中,当温度为270℃,压力为3.0MPa,空速为4800h-1时,CO2的单程转化率达到27.12%,二甲醚的选择性达到47.63%。采用BET、XRD、TPR、TPD等对催化剂结构进行表征,结果表明HZSM-5分子筛的加入促进了CuO组分的分散,增加了催化剂整体的比表面积;同时CuO-ZnO-Al2O3组分也在一定程度上改变了HZSM-5的酸性中心的强度以及数量。

The bifunctional catalysts of CuO-ZnO-Al2O3/HZSM-5 for dimethyl ether synthesis from CO2 hydrogenation were prepared by suspended parallel-flow-coprecipitation, dry mixing and wet mixing methods, respectively. Effects of the preparation methods on the catalytic performance were investigated. The results showed that the coprecipitated catalyst had optimum activity, and at 270℃, 3.0MPa and space velocity of 4800h^-1, the one-through conversion of CO2 could reach 27.12% with the selectivity to dimethyl ether of 47.63%. The BET, XRD, TPR and TPD characterization results indicated that the introduction of HZSM-5 zeolite improved the dispersion of CuO and the specific surface area of the catalysts. Compared to pure HZSM-5, the intensity and quantity of the acidic center of the bifunctional catalysts were modified, which improved the catalytic performance of the catalysts.