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。     

渗透汽化分离乙酸的研究进展

渗透汽化作为一种新型的膜分离技术应用于乙酸的分离,可以优先透水或乙酸。特别是应用在发酵法制备乙酸等低酸含量溶液的分离中,可以优先透酸制备高纯度的乙酸,具有显著的优势。本文综述了渗透汽化技术在分离纯化乙酸中所涉及的膜材料、耦合工艺及其应用现状,并展望了其发展趋势。     

聚二甲基硅氧烷/聚醚砜复合膜渗透汽化分离水中乙酸的性能研究

制备了聚二甲基硅氧烷/聚醚砜(PDMS/PES)复合膜,用于乙酸/水体系的渗透汽化分离。研究了料液质量浓度、温度、流速及下游侧压力对渗透汽化分离性能的影响。实验结果表明,随着料液中乙酸质量浓度的增大,渗透通量增加,而分离因子呈先增大后减小的趋势;随着料液温度的升高,渗透通量增大而分离因子减小;随着料液流速的增大,渗透通量增大而分离因子减小,当达到湍流状态后,两者的变化趋势不明显;随着下游侧压力的增大,渗透通量和分离因子均减小,为获得较好的分离效果应使透过侧保持尽可能高的真空度。     

填充法改性PDMS膜及其对乙酸/水的渗透汽化分离性能

用CTAB-蒙脱石填充改性PDMS膜,运用XRD, SEM等手段表征了不同填充量的复合膜结构,证明有机柱撑蒙脱石与聚合物形成插层型复合物后,膜的热稳定性明显改善. 研究了填充膜对乙酸/水体系的渗透汽化分离性能,结果表明,随着温度的升高,渗透通量增大而分离因子降低,通量随填充量增加单调上升,分离因子随填充量增加先增大后降低,填充量为7.4(%, w)时达到最大值. 从膜的结构及其与组分的相互作用对填充膜中蒙脱石可能存在的渗透通道作用进行了探讨.     

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。     

KAUST-8膜的制备及其对乙醇/水体系的渗透汽化分离性能的研究

为实现乙醇作为燃料的高效利用,采用二次生长法制备出亲水性KAUST-8膜并将其对乙醇水溶液进行渗透汽化分离研究。利用扫描电子显微镜（SEM）、X射线衍射仪（XRD）、比表面及孔隙度分析仪（BET）和热重等分析手段对KAUST-8晶体和膜材料的形貌、结构和性能进行表征,考察了不同操作温度和进料质量分数下,KAUST-8膜对乙醇水溶液分离效果的影响。结果表明,升高渗透汽化的操作温度,总渗透通量从281.44 g/（m²·h）增加至929.16 g/（m²·h）,分离因子从17.2降低至6.1。在同一渗透汽化温度（25℃）下,增大进料液中水的质量分数,水通量从124.2 g/（m²·h）增加到302 g/（m²·h）,总通量逐渐升高至359.2 g/（m²·h）,分离因子逐步从17.2提高至30.2。     

支撑层对硅橡胶复合膜渗透汽化分离性能的影响

引言 为了扩大渗透汽化技术的应用领域,科研工作者需要进一步增强渗透汽化膜的分离性能.从工业化的观点而言,用于实际应用的渗透汽化膜大多是复合膜,它由选择层(或分离层)和支撑层组成.一般认为,选择层决定着复合膜的选择性和通量,支撑层起支撑和机械稳定作用.Nijhuis[1]在从甲苯-水体系中分离甲苯的过程中对均质膜和以聚砜为支撑层的复合膜的分离性能进行了比较;Sturken[2]分别用聚醚酰亚胺和聚偏氟乙烯为支撑层的硅橡胶膜从二氯乙烷-水体系中提取二氯乙烷,他们得到了相同的结论:支撑层的影响可以忽略.然而Scholz[3],Heinzelmann[4],Rautenbach[5],Borges[6],Vankelecom[7],Farooq[8],Lipnizki[9]等均在各自研究中发现,由于基膜和分离层的物理化学性质以及制膜方法等众多因素的存在使得支撑层在一定程度上影响复合膜的分离性能;Feng[10]对均质硅橡胶膜和有微孔支撑层的硅橡胶复合膜的分离性能进行了比较,发现均质硅橡胶膜优先透过异丙醇,而有微孔亲水性支撑层的硅橡胶复合膜则优先透过水,这表明在一定的情况下,支撑层甚至起主导作用并能够决定复合膜的分离性能.因此,通过系统研究以不同多孔材料为支撑层的复合膜对有机物-水溶液的分离性能的影响,能够找到最优的复合膜支撑层,从而能够提高复合膜的分离性能.然而,至今关于支撑层对渗透汽化膜分离性能影响的系统研究仍相当少.     

羧甲基壳聚糖-聚乙烯醇渗透汽化膜分离乙醇-水的性能

本文制备了羧甲基壳聚糖-聚乙烯醇渗透汽化膜,研究了羧甲基壳聚糖和聚乙烯醇配比、戊二醛交联时间以及操作温度和乙醇浓度等因素对膜分离乙醇-水性能的影响。实验结果表明,当乙醇含量较低（10（wt）%）时,该膜优先透醇,羧甲基壳聚糖与聚乙烯醇的比例1∶1时,膜的分离因子达到最大16.45（wt）%的乙醇溶液）;随着戊二醛交联时间的增加,膜的渗透通量减小而分离因子增大;操作温度升高,膜的渗透通量增大,而分离因子降低。     

渗透汽化在生物燃料乙醇制备中的研究进展

渗透汽化作为一种新型的膜分离技术应用于发酵法制备生物燃料乙醇,不但能减少产物对微生物的抑制作用,而且可以脱水制备高纯度燃料乙醇,因而具有显著的优势。本文对渗透汽化在发酵法制备燃料乙醇中所涉及的膜材料、耦合工艺、应用现状和经济评价进行了详细的综述,并对发展趋势作了展望。     

ZSM-5沸石填充聚氨酯膜的制备及渗透汽化分离水中乙酸异丙酯

采用两步法制备了ZSM-5沸石填充的疏水性端羟基聚丁二烯基聚氨酯（PU）膜,用以分离水中芳香性有机物乙酸异丙酯。对该膜的化学结构、形貌及热稳定性进行了表征,并研究了ZSM-5沸石填充的PU膜的溶胀度及渗透汽化性能。结果表明：添加ZSM-5沸石后,膜的热稳定性明显提高,沸石与膜的相容性较好,且随着添加量的增加,膜的溶胀度降低,分离因子先升后降。在303 K、料液浓质量分数为1%的条件下,ZSM-5添加量为20%（质量分数）时,分离因子达到最高;同时随着料液浓度及操作温度的上升,通量和分离因子都增加。在333 K、料液质量分数为1%的条件下,PU-ZSM-5-20膜的分离因子及通量最高可达288.72 g/（m2·h）和53.21 g/（m2·h）。     

渗透气化膜分离技术在乙醇-水体系中的应用

渗透气化是一种新型的膜分离技术,因其具有独特的优势已被广泛应用于乙醇-水的分离.从渗透气化的原理和特点出发,介绍了渗透气化膜材料以及渗透气化与精馏、化学反应耦合等技术,并概述了国内外渗透气化膜分离技术在乙醇-水分离中的应用现状.     

醋酸制备乙醇用催化剂研究

综述了国内外醋酸制备乙醇催化剂的研究现状、技术特点、反应机理及最新进展,指出了醋酸制备乙醇催化剂的研究方向。     

Extraction of Tetrahydrofuran and Ethylene Dichloride Solvents from Aqueous Solutions by Pervaporation through Thin Film Composite PDMS Membranes

Thin film composite (TFC) hydrophobic PDMS membrane of 5 µm active layer thickness supported on Polyethersulfone (PES) ultraporous substrate was synthesized and thermally crosslinked for the pervaporation based extraction of organic solvents such as Tetrahydrofuran (THF) and Ethylenedichloride (EDC) for the first time. The study was extended to acetone, ethanol, t-butanol, Iso-butanol, and acetic acid. Membranes were characterized by SEM, TGA, XRD, and FTIR to study the surface and cross-sectional morphology, thermal stability, crystalline nature, and structural properties, respectively. High selectivities of 868, 72, and 31 were observed at organic feed concentrations of 0.68, 3.42, and 9.38 wt% in water with reasonable fluxes of 0.2, 0.16, and 0.31 kg m^?2 h^?1 for EDC, THF and acetone, respectively at a downstream vacuum of 0.5 mmHg. The estimated mass transfer coefficients (MTCs) were found to be 9.11 × 10^?6, 11.77 × 10^?6, and 10.73 × 10^?6 m s^?1 for THF, EDC, and acetone extraction, respectively. The membrane exhibited considerable feasibility for scale-up due to its composite nature with significant potential for extraction of volatile organic solvents present in low concentrations. A comparison with previous values reported in literature revealed higher selectivities for extraction of EDC, THF and acetone using the present membrane.     

A Review of Membrane Materials for Ethanol Recovery by Pervaporation

Due to an emerging scarcity of oil resources and an associated increase of oil prices, biofuels (e.g., ethanol) play an important role in the energy crisis. Fermentation is a common process for producing ethanol from renewable biomass. Pervaporation is an attractive technique for the recovery of ethanol from the fermentation systems. Separation membrane is the key element in the pervaporation separation equipments. In this article, the pervaporation performances of ethanol-permselective membranes presented in the recovery of ethanol from dilute ethanol aqueous solution are reviewed. An analytical overview on the challenges and opportunities, and the prospect of ethanol-permselective membranes by pervaporation is also discussed.     

PDMS渗透汽化膜分离水中有机物的研究进展

渗透汽化(PV)膜分离技术是一种新型膜分离技术,适用于分离恒沸点混合物、近沸点溶液、热敏感性混合物、有机-有机混合物以及水溶液中少量有机物。PV分离水溶液中有机物的工业应用还处于初步阶段,文中从硅橡胶渗透汽化优先透有机物膜的制备条件、工艺应用参数及膜寿命等方面进行综述。膜生产放大和膜寿命是影响该技术推广的重要因素,可以从膜制备和应用工艺方面进行改进。     

Solubilities of Isophthalic Acid in Acetic Acid + Water Solvent Mixtures

The solubilities of isophthalic acid (1) in binary acetic acid (2)+water (3) solvent mixtures were determined in a pressurized vessel. The temperature range was from 373.2 to 473.2K and the range of the mole fraction of acetic acid in the solvent mixtures was from x₂ 0 to 1. A new method to measure the solubility was developed, which solved the problem of sampling at high temperature. The experimental results indicated that within the temperature range studied, the solubilities of isophthalic acid in all mixtures showed an increasing trend with increasing temperature. The experimental solubilities were correlated by the Buchowski equation, and the calculate results showed good agreement with the experimental solubilities. Furthermore, the mixed solvent systems were found to exhibit a maximum solubility effect on the solubility, which may be attributed to the intermolecular association between the solute and the solvent mixture. The maximum solubility effect was well modeled by the modified Wilson equation.     

生物油中乙酸和乙醇共裂化获取汽油产物的研究简

Abstract Acetic acid was selected as the model compound representing the carboxylic acids present in bio-oil. This work focuses the co-cracking of acetic acid with ethanol for bio-gasoline production. The influences of reaction temperature and pressure on the conversion of reactants as well as the selectivity and Conaposition of the crudegasoline phase were investigated. It was found that increasing reaction temperature benefited the conversion of reactants and pressurized cracking produced a higher crude gasoline yield. At 400 ℃ and 1 MPa, the conversion of the reactants reached over 99% and the selectivity of the gasoline phase reached 42.79% （by mass）. The gasoline phase shows outstanding quality, with a hydrocarbon content of 100%.     

关于醋酸加氢制乙醇技术的分析

本文针对醋酸一步法和两步法加氢制乙醇技术进行了简要介绍,并对两种方法进行了分析比较,得出了一步法相对两步法在技术合理性及生产成本方面具有一定的优势的结论。     

碳纳米管填充PDMS膜的渗透汽化性能

将碳纳米管（CNTs）填充到PDMS中制备出CNTs/PDMS杂化膜,并将其用于乙醇/水体系的分离,发现由多壁碳纳米管制备的膜分离性能优于单壁碳纳米管填充膜,在40℃下,进料乙醇浓度为5%（质量分数）时,膜的分离因子可由8.3提高到10.0,渗透通量为206.2 g·（m²·h）^-1;采用十二烷基三氯硅烷对多壁碳纳米管进行修饰,并对修饰前后碳纳米管的性能进行表征,研究表明修饰后碳纳米管表面形成疏水层,碳纳米管的疏水性增强;将修饰后的碳纳米管填充到PDMS中,可进一步提高杂化膜对乙醇的选择性,膜的分离因子可提高到11.3,渗透通量为130.9 g·（m²·h）^-1。