用湿化学方法合成了SrCo0.5FeO3.25（SC5FO）,La0.15Sr0.85Ga0.3Fe0.7O3-δ（LSGFO）和Ba0.5Sr0.5Co0.8Fe0.2O3-δ（BSCFO）三种透氧膜材料.采用H2-TPR、XRD和透氧测定,并结合膜反应等方法对它们的性质进行了比较研究.LSGFO与BSCFO具有较高的相结构稳定性,而SC5FO较差.LSGFO具有很高的抗还原能力,而BSCFO较差,但它具有优异的相结构可逆性.在air/He氧浓差梯度下,LSGFO和SC5FO导体膜的透氧量较低;BSCFO具有很高的氧渗透能力,850℃下,透氧量高达1.16[STP]mL/cm2·min.SC5FO膜反应器在POM反应开始不久,因为反应端膜表面的材料组成被反应气还原而出现严重的漏气现象,并最终导致实验失败.BSCFO与LSGFO膜反应器成功地应用到POM反应中,进行了长时间的稳定操作,稳态下透氧量分别高达11.5[STP]mL/cm2·min（875℃）与4.0[STP]mL/cm2·min（950℃）.
Three mixed conducting oxygen permeable membranes, i.e. SrCo0.5FeO3.25 (SC5FO), La0.15Sr0.85Ga0.3Fe0.7O3-δ
(LSGFO) and Ba0.5Sr0.5 Co0.8Fe0.2O3-δ (BSCFO) were synthesized by wet chemical methods. A comparative study about their
phase structures, phase and thermo-chemical stabilities, oxygen permeability and membrane reactor performance for partial oxidation of methane to syngas,
was made. After annealing in an Ar atmosphere at elevated temperatures, the pure cubic perovskite structure was survived for LSGFO and BSCFO,
but not for SC5FO. After H2-TPR experiment, the original phase structures of BSCidiiFO and SC5FO were totally destroyed, but the basic
perovskite structure of LSGFO was survived. Multi H2-TPR and re-oxidation results of BSCFO oxide demonstrated that it had excellent phase reversibilities.
The oxygen permeabilities of SC5FO and LSCFO were very low, while a permeation flux as high as 1.1 mL/cm2·min was obtained for a BSCFO membrane at
850℃, which demonstrates its promising application for oxygen separation. Leaking problem was encountered for a SC5FO membrane reactor
during POM reaction, while LSGFO and BSCFO membrane reactors were stably operated in the POM reaction. At 950℃, under POM reaction conditions,
the oxygen permeation flux of LSGFO slowly increased with time, at last (about 300h was needed), a flux about 4 [STP]mL/cm^2·min was obtained,
which was 10 to 40 times higher than that under an air/He oxygen partial pressure gradient. The oxygen permeation flux of the BSCFO membrane can
reach its steady state (850℃C, 10.45 [STP]mL/cm2·min) much quicker (about 21h). The BSCFO and LSGFO reactors were stably operated for
a long time without failure. The high POM operation stability of LSGFO is due to its high thermo-chemical stability. However, for BSCFO membrane
reactor, it is due to its high oxygen permeability and excellent phase reversibility.
参考文献
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