催化与PV双功能中空纤维复合膜制备及其应用过程

Preparation and application processes of difunctional hollow fiber composite membranes with catalysis and pervaporation

以聚丙烯腈(PAN)中空纤维膜为支撑底膜,聚乙烯醇(PVA)为渗透汽化(PV)层,全氟磺酸树脂(PFSA)-聚乙烯醇(PVA)-纳米材料(SiO2、Al2O3和TiO2)为催化层,制备了具有催化和PV双功能的PFSA-PVA-SiO2(Al2O3和TiO2)/PVA/PAN中空纤维复合膜.以乙酸-乙醇酯化反应塔顶粗酯考察其分离性能,以乙酸-乙醇酯化反应考察其催化性能,同时还考察了分离膜作为规整填料的精馏性能.实验结果表明:催化层和PV层能紧密粘结在底膜上,具有良好的PV性能,其渗透通量约170 g/(m2.h),对乙醇的选择性高于27,且无乙酸乙酯透过,以及具有良好的催化性能;当复合膜用作规整精馏填料时,与传统精馏填料相比,能显著降低HTU(小于10 cm);与文献中的中空纤维膜规整填料相比,气液在膜的管层、壳层分开与否对HTU影响不大.

Difunctional hollow fiber composite membranes （PFSA-PVA-SiO2 （ Al2 O3 and TiO2 ）/PVA/ PAN） with catalysis and pervaporation （PV） were prepared, in which employed PAN as support membrane, PVA as separative layer, and PFSA-PVA-nanoparticles （SiO2, Al2 O3 and TiO2） as catalytic layer. The separation performances of difunctional membranes were investigated by dehydrating the top product of ethanol-acetic acid esterifiaction reaction, the catalytic activities of them were studied through ethanol acetic acid esterification reaction, and the distillation performances of single functional pervaporation membranes as structural packings were explored by separation ethanol-water solution. The results showed that both of the separative and catalytic layers were coated on the PAN support membrane tightly; the difunc- tional membranes had remarkably separation performances in terms of permeation fluxes I-approximately 170 g/（m2 · h）] and separation factors （separation factors of water to ethanol were all higher than 27, and no ethyl acetate permeated） ; the difunctional membranes had good catalytic activities and the ethanol- acetic acid esterification conversion could reach to 56. 5% when using them as catalyst. When used single functional pervaporation membranes as structural packings in distillation, the HTU was decreased significantly （lower than 10 cm） compared with conventional distillation packings, and the gas and liquid on either side of the hollow fiber （tube side or shell side, in literatures） or both on the shell side （in this experiment） had little influences on HTU.