担载型中空纤维混合导体氧渗透膜的制备与性能研究

采用干湿法纺丝技术制备Sr_0.7Ba_0.3Fe_0.9Mo_0.1O_3-δ(SBFM)中空纤维支撑体, 以Nb₂O₅掺杂的SrCo_0.8Fe_0.2O_3-δ (SCFNb)为膜材料, 采用旋转喷涂结合共烧结技术制备出担载型SCFNb/SBFM中空纤维氧渗透膜。借助于XRD、SEM、热膨胀分析、透氧及膜反应性能测试等手段, 分别对样品的晶相结构、膜微观结构、支撑体与膜层的烧结行为、膜的氧渗透通量及膜反应性能进行了研究。结果表明, 膜层与支撑体的晶相结构仍保持钙钛矿主体相。支撑体具有单一海绵孔/指状孔结构, 膜厚为5 μm且致密无缺陷, 膜层与支撑体结合良好。在900℃时, 氧渗透通量达到0.74 mL/(cm²·min)。850℃下甲烷部分氧化膜反应稳定操作超过200 h, 稳态下氧渗透通量为4.5 mL/(cm²·min)。研究表明, 担载型SCFNb/SBFM中空纤维氧渗透膜具有较高的氧渗透通量, 同时具有良好的膜反应稳定性。

Preparation and Characterization of Mixed-conducting Supported Hollow Fiber Membrane

Sr_0.7Ba_0.3Fe_0.9Mo_0.1O_3-δ (SBFM) hollow fiber supports were prepared by dry-wet spinning technology. SrCo_0.8Fe_0.2O_3-δ doped Nb₂O₅ (SCFNb) was selected as membrane material, SCFNb/SBFM supported hollow fiber membranes were successfully prepared by a combined spin-spraying and co-sintering method. XRD, SEM, thermal expansion technique, oxygen permeability and membrane reaction tests were utilized to characterize the crystal phase structures, microstructure, sintering behavior, oxygen permeation flux, and reaction performance of membranes and/or supports, respectively. XRD patterns show that the membranes and supports are composed of perovskite main phase. SEM images indicate that the support has an asymmetric structure with a sponge-like microporous/finger-like porous structure. The membrane surface is dense and crack-free, and the membrane layer with a thickness of about 5 μm is well bonded with the support. At 900℃, the oxygen permeation flux of the membrane is 0.74 mL/(cm²·min). No degradation of performance is observed in the membrane reactor under partial oxidation of methane during continuously operating for 200 h at 850℃, and the oxygen permeation flux can reach 4.5 mL/(cm²·min). It is demonstrated that the SCFNb/SBFM supported hollow fiber membrane exhibits high oxygen permeation flux and good stability of the membrane reactor.