炭膜气体分离性能研究

以酚醛树脂为原料制备了炭支撑膜和炭－炭复合膜，研究了其气体分离性能。结果表明：炭支撑膜分离气体和机理包括努森扩散和粘性流；采用浸涂－干燥－炭化的工艺制备的炭－炭复合膜对Ｈ２／ＣＯ２具有较好的分离性能，Ｈ２／ＣＯ２分离系数达５．６，大于理想努森扩散的分离系数３．７。但在高压差时复合膜上ＣＯ２的表面扩散增强，使Ｈ２／ＣＯ２分离系数下降。     

气体分离用管状炭分子筛膜

以无机陶瓷管为支撑体、热塑性酚醛树脂为原料,经高温炭化制备了炭分子筛膜。用低温N2吸附的方法测定了炭分子筛膜的比表面积,用扫描电子显微镜对膜的形貌和厚度进行了表征。考察了膜的气体透过率以及气体的理想选择性随温度的变化关系:H2、CO2、O2、N2和CH4的透过率随温度的升高而增大;理想选择性α(H2/N2)、α(CO2/N2)、α(CO2/CH4)随温度的升高而减小,而α(O2/N2)随温度的升高先增大后减小,在90℃左右气体选择性达到最大。最后由阿累尼乌斯公式计算了气体透过炭分子筛膜的活化能,进一步说明气体透过机理为活化扩散。     

杂化炭膜的制备及其气体分离应用研究进展

杂化炭膜是一种新型的无机气体分离膜材料,在有效分离气体的应用中有广阔的工业化前景.综述了杂化炭膜制备过程中有机聚合物、掺杂物的选择及采用的涂膜方式和炭化条件对膜分离性能的影响及其在气体分离应用方面的研究进展,并对杂化炭膜的发展方向进行了展望.     

Fe/C杂化炭膜的制备及其气体分离性能

将二茂铁作为有机添加剂引入炭膜前驱体聚酰亚胺,经高温热解制备了Fe/C杂化炭膜。考察了二茂铁的添加量对杂化炭膜气体渗透性能的影响。采用热重、红外、X射线衍射和透射电镜等分析方法对所制备的杂化炭膜进行了表征。结果表明,在前驱体中添加二茂铁能显著提高炭膜的气体渗透性能,随着添加量的增加,膜的气体渗透系数明显增加而分离系数则减小,当二茂铁添加量为15%时,对H₂、O₂、N₂、CO₂、CH₄等纯气体的渗透系数分别为2806、1039、266、31、8 barrer,对O₂/N₂、CO₂/N₂、CO₂/CH₄的分离系数分别为8.6、33.5、129.5。Fe/C杂化炭膜是基于“分子筛分”机理分离气体分子。     

自支撑石墨烯炭膜的制备及气体分离性能

通过溶剂蒸发法得到聚酰胺酸（PAA）与氧化石墨烯（GO）的复合石墨烯膜,并经600℃炭化制备了具有良好柔韧性的仿贝壳珍珠层结构的自支撑石墨烯炭膜。通过X射线衍射和场发射扫描电镜对薄膜微观结构进行表征,并测试不同PAA固含量制备的石墨烯炭膜对CO₂和CH₄的分离性能。结果表明,炭化后,GO被还原成石墨烯,呈层状堆叠,堆叠的层间填充了空穴和残炭;石墨烯炭膜的CO₂渗透通量和CO₂/CH₄分离理想选择性随PAA加入量增加,CO₂通量最高可达824 barrer,此时CO₂/CH₄理想选择性达38.9。石墨烯层骨架和碳分子筛构成石墨烯炭膜的气体传输通道,本研究成果为柔性自支撑气体分离炭膜的制备开辟了新思路。     

气体分离用炭膜

在大量文献及作者工作的基础上,对气体分离用炭膜的分离机理、制备及应用进行了综述。     

聚醚砜酮基炭膜的制备及其气体分离性能

采用浸渍涂膜法,以商用聚醚砜酮(PPESK)为前驱体制备了管式复合炭膜,考察了涂膜次数、改性剂及其加入量对所制备炭膜的气体分离性能的影响.结果表明,随着涂膜次数增多,气体分子的渗透速率逐渐减小而选择性呈增大趋势;加入改性剂后的复合炭膜渗透速率和分离系数均有不同程度的提高,表明改性剂不仅改善了涂膜液与支撑体之间的复合效果、减少涂膜次数,同时也促进了气体渗透速率的提高.利用扫描电镜对复合炭膜的微观形貌进行观测,可以看出,复合炭膜由支撑体和分离膜层2部分组成.膜表面很致密均匀,无明显缺陷,分离层薄而均一,厚度在5μm左右,且与支撑体结合紧密.     

气体分离膜综述

介绍了一种新兴的化工单元操作-气体膜分离，对膜分离器及其应用产生的效益进行了阐述，并展望了今后的发展方向。     

炭分子筛膜气体分离传递机理研究的新进展

炭分子筛膜由于其本身具备的独特优势以及其在气体分离方面的应用潜力,已引起了世人的关注.但对炭分子筛膜分离机理特别是传递过程机理研究的不足限制了其发展.本文介绍炭分子筛膜气体分离机理特别是传递过程机理研究的最新进展,包括针对制备方法不同所建立的气体传递机理模型,如Maxwell模型和Bruggeman模型;详细介绍了两种孔结构模型平行阻力模型和阻力串联模型.在此基础上,分析了各模型中存在的问题和不足,认为需要对炭分子筛膜进行进一步的完善并建立合理的传递机理模型,才能推动炭分子筛膜用于气体分离的进程.     

气体膜分离混合气中二氧化碳的研究进展

气体膜分离技术作为碳捕获方案被国际社会认为是最有发展潜力的脱碳方法之一.综述介绍了中空纤维膜接触器、膜结构、系统工艺和吸收剂的研究现状.相对于水和碳酸盐类,醇胺具有的二氧化碳吸收率高、反应热低、反应速度快以及容易再生等优点,在研究与工业过程中是应用最广泛的吸收剂之一.     

高性能气体分离聚苯胺膜

系统论述了聚苯胺自支撑膜和复合膜对气体的分离性能。聚苯胺自支撑膜、聚苯胺 /尼龙、聚苯胺 /氧化铝复合膜经去掺杂尤其是二次掺杂后 ,气体分离系数会显著提高 ,而透气系数略有提高。二次掺杂态聚苯胺自支撑膜和复合膜都具有极高的氧氮分离性能 ,已超过了一般聚合物材料的上限 ,最优异的聚苯胺膜的氧氮选择分离系数可达 30 ,它在包括有高选择性能膜材料聚酰亚胺、聚吡咙、聚三唑等在内的所有聚合物膜中排行第一 ,对空气分离显示出极大优势。预计聚苯胺复合膜及纳米膜在医疗保健等领域具有很大应用潜力     

Targeting the development of membranes for gas separation

This paper presents the new concept of ‘Targeting’ the properties of new membrane materials. Cost parameters are defined in terms of effective selectivity and cost permeability. These new parameters, obtained from the analysis of membrane plant suppliers' bids, are used in a procedure which determines the optimal degree of separation and recovery. The use of the targeting methods is illustrated here in the development of new membranes for the separation of CO from an H₂/CO syngas for the large-scale manufacture of acetic acid. The targeting approach can be extended to include other gas separation technologies and will aid the development of a generic methodology for the design of gas separation processes.     

6FDA-TAPOB hyperbranched polyimide-silica hybrids for gas separation membranes

Physical and gas transport properties of hyperbranched polyimide-silica hybrid membranes were investigated. Hyperbranched polyamic acid as a precursor was prepared by polycondensation of a triamine, 1,3,5-tris(4-aminophenoxy) benzene (TAPOB), and a dianhydride, 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), and subsequently modified a part of end groups by 3-aminopropyltrimethoxysilane (APTrMOS). The hyperbranched polyimide-silica hybrid membranes were prepared by sol–gel reaction using the polyamic acid, water, and alkoxysilanes. 5% weight-loss temperature of the hybrid membranes increased with increasing silica content, indicating effective crosslinking at polymer-silica interface mediated by APTrMOS moiety. On the other hand, glass transition temperature of the hybrid membranes prepared with methyltrimethoxysilane (MTMS) showed a minimum value at low silica content region, suggesting insufficient formation of three-dimensional Si O Si network compared to the hybrid membranes prepared with tetramethoxysilane (TMOS). CO₂, O₂, N₂, and CH₄ permeability coefficients of the hybrid membranes increased with increasing silica content. Especially for TMOS/MTMS combined system, the hybrid membranes showed simultaneous enhancements of gas permeability and CO₂/CH₄ separation ability. It was concluded that the 6FDA-TAPOB hyperbranched polyimide-silica hybrid membranes have high thermal stability and excellent CO₂/CH₄ selectivity and are expected to apply to high-performance gas separation membranes. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Hydrophobic inorganic membranes for water/gas separation

Macroporous or mesoporous hydrophobic inorganic membranes are prepared by a simple one-pot synthesis method coupling the sol–gel process with fluorinated silanes as precursors and the use of alumina powders as fillers. The porosity of these intrinsically hydrophobic membranes can be tuned by the particle size distribution of the dispersed alumina powder. These membranes developed for water/gas separation applications are characterized in term of gas permeance and water breakthrough pressure. A value of air permeance equal to 1800 L min⁻¹ bar⁻¹ m⁻² associated with a water breakthrough pressure larger than 10 bar are measured for the effective sample.     

Uniformity control and ultra-micropore development of tubular carbon membrane for light gas separation

Tubular carbon molecular sieve (CMS) membranes have been recognized as a potential module for commercial application due to its high mechanical strength and large surface area. However, the carbon layer uniformity was restricted by substrate texture and dope fluidity when the dip-coating method was used. This study evaluated the influence of various parameters of dip-coating with an integrated vacuum-assisted system, including solvent vaporization rates, vertical immersion/withdrawal velocity, vacuum degree, dope composition, coating cycles on the microstructure, and gas separation performance of CMS membranes. Using vacuum assistance and a low-vaporization solvent minimized the influence of viscosity and gravity on dope fluidity as a result of fast phase inversion. The as-prepared tubular CMS membranes showed enhanced perm-selectivity according to a H₂/N₂ gas selectivity of 8.8, a CO₂/N₂ gas selectivity of 6.7, a H₂ permeability of 464 barrer, and a CO₂ permeability of 356 barrer.     

大规模膜法空气分离技术应用进展

富氧空气、氧气、氮气以及其他一些空气分离产品应用领域的增加 ,极大地推动了空气分离新技术的大规模发展。膜法空气分离以其节能、便利、安全等优异特性在空气分离产品的工业生产中展现出了极大的发展潜力。综述了现有膜材料的氧氮分离性能、制氧装置和制氮装置的研究开发及其在柴油发动机富氧燃烧等方面的应用研究 ,分析了膜法空气分离大规模商业化必须克服的技术障碍 ,从新型高性能膜材料的合成与制备方面提出了实现大规模膜法空气分离应用应采取的措施。