摘要
由直接合成二甲醚的负载型Cu -Mn -ZnOX γ -Al2 O3 催化剂不同制备方法的研究中发现 :不同的浸渍步骤和催化剂的焙烧温度对反应活性和催化剂的表面活性物种的影响很大 ,而干燥方式的影响较小 ;催化剂表面少量的Mn2 O3 晶相存在对提高二甲醚的选择性有利 ,而晶相CuO和MnO2 的存在则会降低催化剂的活性。不同反应条件的实验结果显示 :温度的提高增加了催化剂的脱水性能 ,但是却导致催化剂的活性降低 ;空速大于 30 0 0h- 1 时 ,CO的转化率迅速下降 ;原料气组成中CO含量的增加 ,其转化率也呈下降趋势 ;合成压力的提高 ,使CO转化率提高相当明显 ;二甲醚的选择性在整个条件试验过程中的变化不十分明显。
Effect of the preparation method and the reaction conditions on the character of Supported Cu-Mn-ZnO X/γ-Al 2O 3 catalyst for the synthesis of DME via CO hydrogenation was investigated It was found that the activity and the surface component changed greatly with the impregnation step and the calcination temperature MnO 2 and CuO phase were found in the surface of the catalyst when Mn(NO 3) 2 was first impregnated, which can reduce the conversion of CO As the calcination temperature raised to above 450℃, Mn 2O 3 phase formed in the catalyst According to the experiment result trace Mn 2O 3 phase can be in favor of the formation of DME The experiment was focused on four areas: reaction temperature, space velocity, concentration of CO in the feeding gas and the reaction pressure The experiment of the reaction temperature showed that: (1) CO 2 was formed mainly from the shift reaction while the vapor formed in the synthesis reaction, (2) the activity of Cu-Mn in the catalyst decreased with the raising temperature It was also found that while the space velocity changed from 7500h -1 to 350h -1 (STP) at 2 0MPa, 275℃, the conversion of CO increased from 21 39% to 75 83%, the selectivity of DME remains about 70% Methanol decreases from 11 12% to 0 79% CH 4, C 2H 6, C 3H 8 appeared and increased from zero to 1 79%, 1 62% and 1 0% respectively As the concentration of CO decreased from 50 0 to 6 0, the conversion of CO increased slowly from 55 30% to 74 39%, while the selectivity of DME decreased slowly from 74 90% to 67 62% But the selectivity of byproduct CH 3OH, CH 4, C 2H 6, C 3H 8 increased quickly with the increasing H 2 in the feeding gas The conversion of CO increased quickly with the increasing pressure, while the selectivity of DME changed little with the pressure and hydrocarbons increased with the pressure
出处
《燃料化学学报》
EI
CAS
CSCD
北大核心
2000年第6期555-559,共5页
Journal of Fuel Chemistry and Technology
基金
浙江省自然科学基金!资助项目 (项目编号 :ZD990 3)
