混合导体透氧膜反应器中甲烷部分氧化反应的催化行为(英文)

应用组成为Ba0.5Sr0.5Co0.8Fe0.2O3-(的钙钛矿型混合导体陶瓷膜制成膜反应器。该膜在进行氧分离的同时具有活化甲烷氧化偶联的催化功能。随着温度升高和膜的富氧端氧分压的增大，透氧量有所增加。在空气、氦气的氧分压梯度下，850(C，膜厚度为1.5 mm时，JO2可达到1.2 mL/(cm3(min)。同时在800(C~900(C温度范围内，该膜对于甲烷转化为乙烷和乙烯一般只具有0.5%~3.5%的低转化率，而选择性可达40%~70%。在反应尾气中发现了大量的未反应的分子氧，说明过量的氧与甲烷未经催化反应的气相反应导致了C2的选择性相对较低。OCM膜反应模式情况下的透氧量与空气、氦气梯度情况下的透氧量相比只有微小增加，这与POM膜反应模式情况下透氧量大量增加显著不同。

CATALYTIC BEHAVIOR OF A MIXED CONDUCTING OXYGEN-PERMEABLE MEMBRANE REACTOR FOR METHANE OXIDATION

A mixed conducting perovskite-type Ba0.5Sr0.5Co0.8Fe0.2O3-( ceramic membrane reactor was applied for the activation of methane, the membrane reactor served as oxygen provider and OCM catalyst at the same time. The oxygen permeability of the membrane increased with the increase of temperature or oxygen partial pressure at the oxygen-rich membrane side (PO2(). At 850(C and under air/He oxygen partial pressure gradient, JO2 reached about 1.2 mL/(cm2(min) for a 1.5 mm thickness membrane. The membrane had catalytic activity for the conversion of methane to ethane and ethylene with C2 selectivity up to 40%~70%, albeit that the conversions were low, typically between 0.5%~3.5% at 800(C~900(C. Large amount of unreacted molecule oxygen was found in the eluted gas, which led to the relatively low C2 selectivity due to the noncatalytic homogeneous reaction of methane and carbon-contained products with molecule oxygen. The oxygen permeation flux at the OCM reaction mode increased only slightly compared with that under non-reactive air/He oxygen gradient, it is much different from that at POM reaction mode, the oxygen permeation flux at POM mode increased about ten folds than that at air/He oxygen gradient.