共查询到20条相似文献,搜索用时 15 毫秒
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在自由体积扩散理论的基础上,提出了渗透蒸发过程中二元水溶液在聚合物膜中扩散的修正自由体积模型。模型中定义了2个共存因子,用以描述非理想物系在渗透蒸发膜扩散过程中的共存效应。结合4种水溶液在聚酰亚胺(PMDA-ODA)膜中的吸附实验数据所计算的膜相浓度,用本模型拟合了上述物系的渗透蒸发实验数据,获得较一致的结果。 相似文献
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用交联聚乙烯酸膜对不同浓度的乙二醇/水溶液在不同温度下分别进行了渗透蒸发实验研究.针对小分子在致密膜中的扩散行为提出了一个新见解,并借用改进的Vigne方程得到了一个新的热力学扩散系数方程,用此方程结合Lee-Thods方程、Wilke-Chang方程、Vrentas和Duda改进的自由体积理论、扩散方程和溶胀平衡方程预测了水和乙二醇分子在不同温度下通过交联聚乙烯醇膜的渗透蒸发行为,其预测结果与实验值基本一致. 相似文献
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改性聚酰亚胺膜用于甲醇/甲基叔丁基醚的渗透汽化分离 总被引:1,自引:0,他引:1
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。 相似文献
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分离有机物水溶液的渗透汽化与汽化渗透膜 总被引:6,自引:0,他引:6
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 相似文献
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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. 相似文献
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Lloyd Berg 《Chemical Engineering Communications》1990,88(1):63-67
m-Diisopropylbenzene can be separated from p-diisopropyl-benzene by azeotropic distillation when the azeotrope forming agent is selected from certain ketones, e.g. acetophenone; alcohols, e.g. o-isopropyl-phenol; esters, e.g. methyl benzoate; ethers, e.g. dipropylene glycol dimethyl ether or nitrogeneous compounds, e.g. 2-nitrotoluene. 相似文献
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亲水—憎水膜用于渗透汽化法分离乙醇/水的研究 总被引:1,自引:0,他引:1
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。 相似文献
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藻朊酸钠渗透汽化膜分离有机液/水混合物 总被引:1,自引:0,他引:1
研究了藻朊酸钠均质膜及藻朊酸钠/酸丙烯腈复合膜的渗透汽化特性。发现它们对甲醇、乙醇、异丙醇、丙酮、四氢呋喃(THF)、二氧六环、丙三醇等有机溶剂与水的混合望远镜水优选 透过,其渗透通量与选择分离系数都非常高。复合膜与均质膜相比,通量成倍增加,除甲醇/水体系外,对其他体系的分离系数不大,对二氧六环/水体系的分离系数复合膜更高。三种藻朊酸钠样品对乙醇/水,二氧六环/水的透过分离性能有所差异,对此,从膜 相似文献
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A set of transport equations was derived for the separation of the binary mixtures of organic solvents on the basis of the surface force-pore flow (SFPF) model. These equations enable the quantitative prediction of the membrane performance data under a given set of operating conditions together with the information on the membrane pore size, interaction forces working between the solution components and the membrane material, and the activity and the molecular radii of solution components. The usefulness of such transport equations is shown for the system ethyl alcohol-heptane-cellulose membrane and some other separation systems. 相似文献
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混合电解质溶液在多孔颗粒内扩散的数学模型 总被引:1,自引:0,他引:1
建立了混合电解质溶液在多孔颗粒内扩散的数学模型,并由此计算了交互扩散效应的大小;讨论了单一扩散系数的菲克定律描述电解质混合物扩散的适用性;用模型处理了HCl-KCl-H_2O体系的实验数据,得出了有效主扩散系数和有效交互扩散系数. 相似文献
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分别研究了甲醇(MeOH)和甲基叔丁基醚(MTBE)纯纽分在二醋酸纤维素(CA)和三醋酸纤维素(CTA)膜内的吸着性能、扩散系数及渗透通量.结果表明,活度在0.2~1.0范围内,MeOH在CA和CTA膜内的平衡吸着质量分数分别为0.018~0.172和0.032~0.175,远大于MTBE,而组分在2种膜中的溶解度无明显差别,2种组分在CTA膜中的扩散系数和渗透通量均大于CA膜.考察了进料温度在25℃、32℃和40℃下,料液中MeOH质量分数为5%~35%时,MeOH/MTBE混合物在CA膜中的渗透通量和分离系数,结果表明,随着进料温度和料液中MeOH浓度的升高,通量增加,分离系数减小. 相似文献
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本文通过渗透汽化过程中物料,热量衡算,进行合理假设,建立工艺流程设计的数学模型,为中空纤维膜器在渗透气化过程应用提供设计依据,并以生产无水乙醇为例求解出数学模型。 相似文献
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The present work considers the application of an integrated pervaporation process to improve the pervaporation performance of acetic acid over water. This integrated pervaporation process was based on a plain PDMS membrane with a hydrophobic ionic liquid composed of a heterocyclic cation and [PF6]- anions. The hydrophobic ionic liquid was introduced as the third phase between the aqueous phase and the plain PDMS membrane for improving mass-transfer of acetic acid from its aqueous matrix to the PDMS membrane. The primary results indicated that the ionic liquid as an extractant prior to pervaporation was favorable for improving the permeate selectivity and the permeate flux of acetic acid compared with using only a plain PDMS membrane. This performance could be attributed to the acetic acid concentrated and the water molecules rejected by ionic liquid prior to pervaporation. Extraction of a real effluent containing acetic acid from an antibiotic pharmaceutical plant was carried out using the above integrated pervaporation, and the results imply that this integrated pervaporation process could be scaled up for recovering acetic acids over its water-rich effluents. 相似文献