Fast Oxygen Separation Through SO2- and CO2-Stable Dual-Phase Membrane Based on NiFe2O4-Ce0.8Tb0.2O2-δ
Fast Oxygen Separation Through SO2- and CO2-Stable Dual-Phase Membrane Based on NiFe2O4-Ce0.8Tb0.2O2-δ
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DOI：
10.1021/cm4034963
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发表时间：
2013-12-24
影响因子：
8.6
通讯作者：
Serra, Jose M.
中科院分区：
文献类型：
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作者：
Balaguer, Maria;Garcia-Fayos, Julio;Serra, Jose M.
报道了在氧气燃料类气体环境中具有增强的透氧性和前所未有的稳定性的复合膜。具体地说，采用一锅法制备了既有尖晶石相又有萤石相的60体积%NiFe2O4-40体积%Ce0.8Tb0.2O2-Delta(NFO-CTO)复合材料。得到了以1微米为中心的窄粒度分布和均匀的颗粒分布，以及从侧面到侧面的渗透通道。该复合材料在800摄氏度的湿二氧化硫和二氧化碳气体中耐受170小时的稳定性测试，这标志着它在氧气燃料发电厂中的使用向前迈进了一步。研究了两相的电导率随温度和氧分压(Po(2))的变化。在这种NFO掺杂CeO2复合膜中，氧的分离是通过两个截然不同的渗流网络进行的。通过0.68 mm厚的膜，在1000℃时，分别获得了0.17mL中心点min(-1)中心点cm(-2)和0.20mL中心点min(-1)中心点cm(-2)的透氧量。900℃下的实验表明，该材料在纯CO2气氛中稳定有效，在CO2气流中放置76h后，透氧率甚至有所提高。
Composite membranes with enhanced oxygen permeability and unprecedented stability in oxyfuel-like gas environments are reported. Specifically, 60 vol% NiFe2O4 - 40 vol% Ce0.8Tb0.2O2-delta (NFO-CTO) composite has been successfully obtained by one-pot fabrication method showing both spinel and fluorite pure phases. Narrow grain size distribution centered around 1 mu m and homogeneous distribution of grains is attained, as well as percolative pathways from side to side of the dual-phase membranes. The composite resisted a stability test in wet SO2 and CO2 containing gas at 800 degrees C for 170 h, which represents a step forward toward its use in oxyfuel power plants. The conductivity of both phases is investigated as a function of temperature and oxygen partial pressure (pO(2)). Oxygen separation in this kind of NFO-doped-ceria composite membranes occurs via the separate ambipolar transport through the two distinct percolating networks. Oxygen permeation flux values of 0.17 mL center dot min(-1)center dot cm(-2) and 0.20 mL center dot min(-1)center dot cm(-2) are achieved at 1000 degrees C when argon and pure CO2 are used as sweep gas, respectively, through a 0.68 mm-thick membrane. Experiments at 900 degrees C showed that the material is stable and effective in pure CO2 atmospheres and the oxygen permeation is even improved after 76 h on CO2 stream.