聚酰亚胺中空纤维膜的热亚胺化及碳化的研究

聚酰亚胺（P1）是一种性能忧良的新型膜材料。就其在热亚胺化过程中的一些因素对膜性能影响及碳化过程中的PI膜结构变化怍一定的研究与分析讨论,从而推断其可能的结构变化,     

中空纤维膜气体分离器的数学模型

本文建立了中空纤维膜气体分离器的微分数学模型,对其数值解进行了实验验证,又将其简化的代数模型同文献上的模型进行了比较,指出了各种模型适宜的使用条件,并研究确定了气体膜分离过程中较适宜的丝内径、丝长度和操作压力的范围。     

制备条件对聚酰亚胺中空纤维膜性能影响的研究进展

综述了内部和外部凝固剂的化学性质、凝固浴温度等对聚酰亚胺（PI）中空纤维的形态和对PI中空纤维膜的气体分离,性能的影响。同时,叙述了纤维塑化抑制和亚胺化条件控制等对提高PI中空纤维膜分离性能的作用.     

含砜基聚酰亚胺的合成及其中空纤维膜的制备（英文）

以4,4'-(六氟异丙烯)二酞酸酐(6FDA)与4,4'-双(4-氨基苯氧基)二苯砜(BAPS)为反应单体,以N-甲基-2-吡咯烷酮(NMP)为溶剂,合成了聚酰胺酸(PAA),将PAA溶液采用流延成膜的方法制备成薄膜;另外,将PAA溶液采用干-湿法纺丝工艺制得PAA中空纤维膜,再将PAA薄膜及其中空纤维膜在300℃左右的高温热环化制得6FDA-BAPS型聚酰亚胺(PI)膜。研究了6FDABAPS型PI及其中空纤维膜的结构与性能。结果表明:所合成的6FDA-BAPS型PI为目标产物,其在NNP、N,N-二甲基乙酰胺、四氢呋喃中具有良好的溶解性能。6FDABAPS型PI中空纤维膜外皮层致密、支撑层疏松多孔,该中空纤维膜具有较高的热学性能和力学性能,在氮气氛围中热失重5%的温度为511℃,断裂强度为26.5 MPa。     

中空纤维膜气体溶剂的吸收分离过程

测定了不同条件下聚丙烯疏水性中空纤维膜组件中ＣＯ２－ＮａＯＨ体系气体溶剂吸收过程的总传质系数．建立了溶剂吸收过程总传质系数的计算模型．以此模型为基础,结合实验结果对气体溶剂吸收过程进行了分析,提出了提高总传质系数的有效方法．     

中空纤维膜组件分离酸性气体

研究了气体膜分离与溶剂吸收相结合的分离技术.以NaOH水溶液为吸收剂,在中空纤维膜组件中实现二氧化硫气体的选择性吸收.研究了在三种不同结构的疏水性聚丙烯中空纤维膜组件中,吸收剂浓度、液速、气速、气液两相在膜组件内的流程、膜结构等对分离过程的影响;根据膜结构的实际参数确定了多孔膜的曲率因子,总传质系数的计算值与实验值相符.     

气体分离用聚砜中空纤维膜的活化涂敷技术

主要探讨了一些表面活性剂对气体分离用聚砜中空纤维膜表面涂敷上的作用。结果表明 ,其中TO 80对提高H2 /N2 分离系数的效果最佳。     

单外皮层PES中空纤维气体分离膜制备的研究

以聚醚砜(PES)作膜材料,N-甲基吡咯烷酮(NMP)为溶剂,乙醇(Ethanol)作非溶剂,NMP-Water为芯液,获得PES/NMP/Ethanol铸膜液[m(PES)∶m(NMP)∶m(Ethanol)=35∶57∶8],采用相转化法制备了PES中空纤维气体分离不对称膜,研究了保存时间、硅橡胶种类、芯液浓度、芯液流量和凝胶温度等对PES中空纤维膜O2/N2渗透性能的影响。同时,分析了单外皮层PES中空纤维气体分离膜的结构,讨论了PES中空纤维气体分离膜的机械性能。当芯液组成的m(NMP)∶m(H2O)=86∶14和凝胶温度17℃时,涂3%硅橡胶A后的PES中空纤维气体分离膜气体分离性能如下:αO2/N2=6.68,JO2=2.26GPU,JN2=0.33GPU。     

Improving PVDF Hollow Fiber Membranes for CO2 Gas Capture

Poly(vinylidene fluoride) (PVDF) hollow fiber membranes were obtained by the phase inversion technique. The influence of internal coagulant viscosity (0.001 to 3 Pa s) and air gap (0.6 to 86.4 cm) on the structure and mechanical resistance of the fibers was studied. A “sponge-like” structure free of macrovoids was obtained by using polyvinyl alcohol (PVA) with N-methyl pyrrolidinone and water as internal coagulant (viscosity 3 Pa s). The effect of the air-gap was studied in order to control the structure and obtain mechanically resistant membranes with tensile strength at break between 2.2 and 54.3 N/mm² and pure water permeability ranging from 4 to 199 Lh^?1m^?2bar^?1. CO₂ permeability of these membranes was measured and found to be in the range of 365 to 53200 NLh^?1m^?2bar^?1. The “Dusty Gas” model (DGM) was used to calculate the pore size of the membranes from CO₂ permeability experiments, obtaining pore radius values going from 0.6 to 10.8 µm. Results from modeling were compared with pore sizes observed in SEM images showing that this model can accurately predict pore radius of sponge-like structures; however, pore sizes of membranes presenting sponge-like structures together with finger-like pores were inaccurately predicted by the DGM.     

Performance of Gas Separator with High-Flux Polyimide Hollow Fiber Membrane

Abstract

The permeation properties of H₂-CO mixtures through a high-flux asymmetric polyimide membrane are studied experimentally and theoretically. Experimental results measured with miniature module-equipped hollow fibers indicate the advantage of countercurrent flow pattern. The calculation model used for the analysis of the conventional symmetric membrane can predict the gas separation performance. However, the model is necessary to take the longitudinal mixing into account for analyzing the experimental results measured with a pilot scale module.     

富氮膜分离过程的理论分析和实验研究

本文对用中空纤维膜从空气中富集氮气的过程进行研究,较好地揭示了过程中各参数及膜性能与分离结果的关系.改变实验条件可得到浓度为85%～99.6%的富氮气体,回收率为78%～23%.实验对理论模型进行了验证,结果表明,在实验浓度范围内采用柱塞流逆流模型和全混柱塞流模型的计算值与实验值基本吻合,模型可以满足工业模拟和设计要求.     

含氟聚酰亚胺气体分离膜研究进展

介绍了一种新型气体分离膜材料-含氟聚酰亚胺,着重介绍了含氟聚酰亚胺的物理化学性质、气体选择透过性。对其发展历史及应用作了简要概述。通过与传统聚酰亚胺膜材料进行比较,指出了该膜材料的广阔发展前景,并对其今后发展方向进行了展望。     

A Novel Approach to Gas Separations Using Composite Hollow Fiber Membranes

Abstract

A method has been developed by which a porous hollow fiber which cannot separate gases to a significant extent can be made to exhibit its intrinsic separation properties by coating with an appropriate material. A unique feature of this composited fiber is that the separation properties are determined by the porous support polymer rather than by the coating polymer. The hollow fibers produced by this method have extraordinarily high rates compared to earlier hollow fibers used for gas separations. In addition, they can function under extremely high pressure gradients. Gases such as He, H₂, and CO₂ can be separated from gases like CH₄, CO, and N₂, and the system is chemically and physically stable to a wide range of typical industrial contaminants. As a result, systems based on these fibers should be useful in a variety of processes, some of which include stream splitting, gas composition control, H₂ upgrading, and purge gas recovery.     

Yttria Stabilized Zirconia Hollow Fiber Membranes

Yttria-stabilized zirconia (YSZ) hollow fiber membranes have been developed by a combined phase inversion and sintering method. An organic binder solution (dope) containing suspended YSZ particles is spun to form a hollow fiber precursor, which is then sintered at elevated temperatures. The prepared hollow fibers have the asymmetric structure including the sponge-like structures at center, sandwiched by the long finger-like structures located at the outer and inner walls of the fibers. Experimental results indicate that by controlling the YSZ/polymer weight ratio at 9 or 10 and sintered at a temperature of 1590°C or 1550°C for 10 h, respectively, gas-tight asymmetric YSZ hollow fiber membranes with high mechanical strength can be obtained.     

Preparation of Hollow Fiber Membranes by Nonsolvent Induced Phase Separation along with Hydrogen Gas Formation Using a Single Orifice Spinneret

Traditional nonsolvent induced phase separation (NIPS) process for fabrication of hollow fiber membranes (HFMs) faces challenges, like design and manufacture of spinneret with two concentric orifices to provide parallel and continuous feed of polymer solution and bore fluid at specific rates. These factors limit the use of traditional technique to produce HFMs. Here, a new direct spinning method for fabricating HFMs by feeding a polymer solution, containing a gas producing agent using single orifice spinneret is reported. Polysulfone‐dimethylacetamide solution containing NaBH₄ is extruded through a stainless‐steel needle (single orifice spinneret) into HCl aqueous solution (coagulation bath) at specific rates. Effects of polysulfone concentration, temperature, and pH of coagulant bath on structure and performance of the HFMs are investigated. Synergy between hydrogen from NaBH₄ hydrolysis and NIPS process benefits fabrication of HFMs with good hollow bore structure and high porous wall. The prepared HFMs show good dye separation.