反应条件对Mo_2C/Al_2O_3催化的POM制合成气的影响

Effects of Operation Parameters on the POM to syngas over Mo_2C/Al_2O_3Catalyst

考察了反应温度、气体空速和进料中CH4∶O2比值对Mo2C/Al2O3催化的POM反应制合成气的影响.结果发现较高的温度具有较高的甲烷转化率、CO和H2的选择性;而在较低的温度下,对CO的选择性比对H2的影响更大.反应气体的空速较小时对于甲烷的转化率、CO和H2的选择性是有利的;而在较高的气体空速下,氢气的选择性则更低.进料中CH4∶O2比值稍高于2∶1时有利于获得高的甲烷转化率、CO和H2的选择性,并且还可以增加催化剂的稳定性.当CH4∶O2比值低于2∶1时,甲烷转化率、CO和H2选择性随反应的进行急剧下降,而当此比值调整到高于2∶1时,转化率和选择性都可以得到恢复.

The effects of operation parameters, such as reaction temperature, gas hourly space velocity (GHSV) and the ratio of CH\-4 to O\-2 in feedstock, on the POM to syngas over Mo\-2C/Al\-2O\-3 catalyst were investigated. The evaluation results indicate that higher conversion of methane and selectivity to CO and H\-2 at higher reaction temperature were obtained. Moreover, the lower selectivity to CO and higher selectivity to H\-2 at lower temperature were observed. As usual case, lower GHSV is favorable to the POM to syngas, while under the condition of higher GHSV, the selectivity to CO was higher than that to H\-2, which was contrary to the case at lower GHSV. When the ratio of CH\-4 to O\-2 in feedstock was higher than 2.0∶1, the higher conversion of methane and selectivity to CO and H\-2 were obtained because more active phases were formed in the process of the POM to syngas. When the ratio of CH\-4 to O\-2 was less than 2.0∶1, the carbide catalyst lost activity more rapidly. When the ratio of CH\-4 to O\-2 was changed from the value less than 2∶1 to that higher than 2∶1, the conversion of methane and selectivity to CO and H\-2 could be changed from lower to higher value.