CA膜分离MeOH/MTBE混合体系的渗透汽化传质模型

根据UNIQUAC模型和溶解扩散模型,建立了CA膜分离MeOH/MTBE混合体系的渗透汽化(PV)传质模型,模型计算值与试验值吻合良好.采用UNIQUAC模型关联MeOH-MTBE混合液的汽液平衡数据以及MeOH和MTBE在醋酸纤维素膜内的等温吸着数据,得到UNIQUAC相互作用参数,预测混合物组分在膜内的溶解度.用溶液吸着溶胀试验测得了MeOH/MTBE混合物在CA膜内的扩散系数,由6参数模型回归得到各个相互作用参数.     

渗透汽化膜分离MeOH/MTBE混合物的传质分析——单组分在膜中的扩散

用石英晶体微平衡法测定了298.15 K、305.75 K、312.95 K下MeOH（甲醇）和MTBE（甲基叔丁基醚）在CA（醋酸纤维素）膜中的吸着平衡数据和吸着动力学数据.结果表明：MeOH和MTBE在CA膜中的传质过程属于Fick扩散类型;MeOH在CA膜中的平衡吸着量和扩散系数都比MTBE大,说明CA膜对MeOH/MTBE混合物有较好的分离性能;同一吸着温度下,吸着速度和平衡吸着量均随着吸着蒸气压的升高而升高;可用Eyring的扩散“空穴”理论解释MeOH和MTBE在膜中的扩散行为.     

渗透汽化膜分离乙醇水混合物

以自制的壳聚糖／聚丙烯腈透水复合膜，对乙醇水实行渗透汽化分离，分离因子可达１４０～２５００，含水８．９％～３４．６％（质）的溶液，透过液中含水高达９３％～９９．８％（质），渗透总通量为０．１５～１．２５ｋｇ／ｍ￣２·ｈ。     

用于脱除C5及MTBE中甲醇的渗透汽化膜研究

Several pervaporation membranes, cellulose acetate (CA), polyvinylbutyral (PVB), poly(MMA-co-AA), MMA-AA-BA, CA/PVB blend and CA/poly(MMA-co-AA) blend, were prepared, and their pervaporation properties were evaluated by separation of methanol/C5 or methanol/MTBE (methyl tert-butyl ether). The results shows that the CA composite membrane has a high separation performance (flux Jmenthanol =350g.m-2.h-1 and separation factor a > 400) for methanol/C5 mixtures, and the pervaporation characteristics of MMA-AA-BA copolymer membranes changes with the ratio of copolymer. For CA/poly(MMA-co-AA) blend membrane, the pervaporation performance is improved in comparison with CA or poly(MMA-co-AA) membrane. From the experiment of CA/PVB blend membranes for methanol/MTBE mixture, it is found that the compatibility of blends may affect the separation features of blend membrane.     

渗透汽化膜分离过程的研究和应用

本文综述了渗透汽化过程的进展和动向，介绍了国际技术进展状况，主要应用和过程的经济性。同时，提供了该过程的原理简介，膜和膜材料以及过程开发和装置设计研究等主要内容。     

分离有机／有机混合物的PVA，CA系列膜及其渗透汽化性能研究（I）膜材料与成膜工艺

依据溶度参数原则和分离甲基叔丁基醚（MTBE）/甲醇（MeOH）混合物的选择渗透性,选择了聚乙烯醇（PVA）为复合膜的分离层材料,聚丙烯腈（PAN）、醛酸纤维素（CA）系列为支撑层的膜材料。初步讨论了膜材料和复合膜结构对分离性能的影响,给出了用不同成膜工艺制备的膜性能。获得了可用于有机/有机体系分离的性能优良的PVA/PAN和PVA/CA复合膜,以及CTA中空纤维渗透汽化膜。     

分离有机/有机混合物的PVA、CA系列膜及其渗透汽化性能研究(Ⅰ)膜材料与成膜工艺

依据溶度参数原则和分离甲基叔丁基醚(MTBE)/甲醇(MeOH)混合物的选择渗透性,选择了聚乙烯醇(PVA)为复合膜的分离层材料,聚丙烯腈(PAN)、醋酸纤维素(CA)系列为支撑层的膜材料.初步讨论了膜材料和复合膜结构对分离性能的影响,给出了用不同成膜工艺制备的膜性能,获得了可用于有机/有机体系分离的性能优良的PVA/PAN和PVA/CA复合膜,以及CTA中空纤维渗透汽化膜.     

渗透汽化有机膜分离异构体混合物的研究进展

综述了近年来用于异构体渗透汽化分离的有机高分子膜研究情况及最新进展,重点评述了各种膜材料的结构特点,改性原理以及在异构体分离方面的优点和不足.最后对用于异构体渗透汽化分离的有机膜研究进行了总结,并对其发展方向进行了展望.     

EVA膜对甲苯/乙醇混合物的溶胀和渗透汽化特性

利用基团贡献法估算了共聚比不同的乙烯 /醋酸乙烯共聚物 (EVA)、甲苯 /乙醇混合物的Hansen溶解度参数 ,以共聚物与混合物两者间的三维及二维溶解度参数分量差为判据 ,分析了二者之间相互作用关系及互溶状况 ,与醋酸乙烯质量分数为 2 8%和 14 %的EVA溶胀实验结果对比 ,估算值与实验结果较一致 .所研制的膜用于分离甲苯 /乙醇混合溶液 ,甲苯为优先透过组分 ,在甲苯的质量分数为 2 %～ 3 5 %之间 ,进料温度为 2 5℃的条件下 ,甲苯渗透通量范围为 5 5～ 90 0 g·m^-2 ·h^-1,而分离因子由 18降到 4 .0 .     

有机硅渗透汽化膜分离过程研究

有机硅膜具有对醇－水混合物良好分离性能,以啤酒酵母发酵制取酒精,采用有机硅膜分离提纯酒精。重点讨论了渗透汽化膜循环发酵器工艺条件对分离过程的影响。     

改性聚酰亚胺膜用于甲醇/甲基叔丁基醚的渗透汽化分离

本文以己二酸对聚酰胺羧酸进行改性，制得改性聚酰亚胺膜，用于甲醇／甲基叔丁基醚的渗透汽化分离。研究了制膜液浓度、己二酸含量、原料液组成及温度等条件对膜分离性能的影响，并分析了膜的结构与特征基团的光谱图。     

亲水—憎水膜用于渗透汽化法分离乙醇／水的研究

本文研究了亲水－憎水（ＰＡＭ－ＮＹ６）共混物膜用于水－乙醇混合物的渗透汽化分离。随着共混物膜中ＰＡＭ的含量由７０％上升到１００％（ｗｔ％），膜的分离系数α增加；而其渗透通量则在ＰＡＭ含量约８５％（ｗｔ％）时有一峰值。膜材料的亲水－憎水性与料液中水、乙醇的选择性溶解及渗透汽化过程密切相关。     

REVERSE OSMOSIS SEPARATION OF GLUCOSE-ETHANOL-WATER SYSTEM BY CELLULOSE ACETATE MEMBRANES

The separation of glucose-ethanol mixed solutes from aqueous solutions was attempted by cellulose acetate membranes of different average pore sizes and pore size distributions at the operating pressure of 6895 kPag (=1000 psig) and at the feed glucose concentration ranging from 2000 to 75000 ppm while maintaining ethanol concentrations at 1/5 to 1/2 of the glucose concentration. Using chosen reference solutes the pore size distribution on the membrane surface was characterized by two normal distributions. It was found that ethanol is attracted to the cellulose acetate membrane material more strongly at the higher glucose concentration in the feed solution, and consequently the separation of ethanol solute is brought down at higher glucose concentrations. These results are attributed to lowering of solubility of ethanol in the solvent when a greater amount of glucose is in the solvent.     

REVERSE OSMOSIS SEPARATION OF GLUCOSE-ETHANOL-WATER SYSTEM BY CELLULOSE ACETATE MEMBRANES

The separation of glucose-ethanol mixed solutes from aqueous solutions was attempted by cellulose acetate membranes of different average pore sizes and pore size distributions at the operating pressure of 6895 kPag (=1000 psig) and at the feed glucose concentration ranging from 2000 to 75000 ppm while maintaining ethanol concentrations at 1/5 to 1/2 of the glucose concentration. Using chosen reference solutes the pore size distribution on the membrane surface was characterized by two normal distributions. It was found that ethanol is attracted to the cellulose acetate membrane material more strongly at the higher glucose concentration in the feed solution, and consequently the separation of ethanol solute is brought down at higher glucose concentrations. These results are attributed to lowering of solubility of ethanol in the solvent when a greater amount of glucose is in the solvent.     

SORPTION BEHAVIOR AND PRELIMINARY PERVAPORATION RESULTS OF CROSS-LINKED POLYVINYLALCOHOL AND POLYDIMETHYLSILOXANE MEMBRANES PREPARED FOR THE SEPARATION OF WATER-ETHYLACETATE MIXTURES

Since pervaporation process is the coupling of solution and diffusion mechanisms, a sorption study was carried out with membranes prepared by cross-linking polyvinylalcohol (PVA) and polidimethylsiloxane (PDMS). Tartaric acid (Tac) was used as the cross-linking agent for PVA, and a commercial cross-linking agent was used for PDMS. Sorption experiments were carried out at 30-50°C temperature range in pure water and ethyl acetate using the films prepared. The PVA and PDMS films prepared preferentially sorb water and ethylacetate, respectively. A pervaporation study at 30°C was carried out for pure ethylacetate and pure water, and mixtures of ethylacetate containing 2 and 2.5 wt% water using 100 μm thick PVA membrane. The results indicate that the PVA membrane prepared is extremely selective for water.     

乙基和硝基纤维素／液晶复合空气分离膜

选用乙基纤维素，硝基纤维素分别与三种液晶（胆甾醇油烯基碳酸酯ＣＯＣ，烷基纤维素ＡＣ，混合液晶ＤＹＣ）共混，制备了两大系列空气分离复合膜。用恒压容量分析法研究了有效分离面积为５０ｃｍ＾２膜的空气分离性能与膜组成，膜存度，操作温度和压力的关系。结果表明，ＥＣ／液晶膜比ＣＮ／液晶膜具有较高的空气分离综合能力。减小膜厚或升高温度可以有效地提高一级富氧空气流量ＱＯＥＡ，但膜厚过小或温度过高，一级富氧空气的氧     

分离有机物水溶液的渗透汽化与汽化渗透膜

该文基于４５篇最新文献，较详细地论述了渗透汽化膜与汽化渗透膜的有机物水溶液分离性能及其影响因素，包括高聚物特征，料液浓度，温度，古游侧压力，膜厚度和操作时间，指出用多数高聚物膜进行渗透汽化操作可以有效地分离多数有机醇，酮，酸，酯，酰胺以及二Ｅ烷，乙腈，吡啶，二甲亚砜和四氢呋喃水溶液；而以壳聚糖及其衍生物膜进行汽化渗透操作则具有更高的分离系数。该文还简要介绍了渗透汽化膜的新应用。为渗透汽化与汽化渗透     

低压醋酸纤维素中空纤维反渗透膜及组件研制

本文报导了以二醋酸纤维素(CA)为原料,通过溶液干湿法多孔纺丝制膜技术生产低压中空纤维反渗透膜及组件的研究成果。研制的TF-100型(4″)RO 组件在以自来水为进水,操作压力1MPa,水回收率50%条件下测试;脱盐率为93%,产水量为200 L/h(25℃)。组件可用于自来水和低度含盐水的脱盐。     

MULTICOMPONENT TRANSPORT OF ELECTROLYTES THROUGH CELLULOSE ACETATE MEMBRANES

A multicomponent transport model is presented to describe the rejection components of electrolyte systems by cellulose acetate reverse osmosis membranes. Comparison of the model with the experimental results obtained with NaCl-CaCl₂-H₂O solutions shows good agreement. It was observed that the presence of CaCl₂ can reduce drastically the rejection of NaCl in this multicomponent system and even cause 'negative rejection' in certain cases. The results of this study will be helpful in better understanding, predicting and controlling the operation of reverse osmosis desalination plants that process multicomponent feeds where interactions among the electrolytes present can affect the performance of the membranes used