渗透汽化技术脱除黄酒中乙醇的实验研究

在40℃,膜下游侧压力为260 Pa下,用自制的硅橡胶复合膜对传统黄酒进行了渗透汽化脱醇研究,重点对黄酒中10种主要风味物质和理化指标的变化进行了分析。实验结果表明,当乙醇的体积分数从25.1%降到6.5%时,黄酒中的乙醛、甲醇、乙酸乙酯和高级醇类的含量显著降低,乳酸乙酯的含量基本保持不变,而乙酸和苯乙醇的含量则增加了3~4倍。低醇黄酒的风味和口感与传统黄酒有较明显的差别,形成独特的风格,但总体上保持了传统黄酒的典型性,并且保健功能有所增强。硅橡胶复合膜的平均总渗透通量为1 500 g/(m2.h),对乙醇的平均分离因子为7.4。     

膜渗透蒸发用于葡萄酒脱醇的实验研究

利用自制的PDMS平板复合膜 ,在 40℃ ,1330Pa下游侧压力下 ,φ(C2 H5OH) =11 5 %的红葡萄酒经过渗透蒸发脱醇后可获得 φ(C2 H5OH) =7%、4%、3%等各种低醇红葡萄酒 ,同时渗透液可勾兑成 φ(C2 H5OH) =30 %～ 5 0 %的高醇白兰地 ,平均总渗透通量达 145 5 g/(m2 ·h)。在小试实验中 ,低醇葡萄酒和高醇白兰地的平均生产强度分别是 4830和 780mL/(m2 ·h)。国家资深评酒专家对两种新酒品都给予了高度评价 ,认为有一定的市场经济价值。     

渗透汽化脱水技术及其在酯化工业中的应用

渗透汽化是分离某一液体物质含量较低的液体混合物的实用分离方法.高性能渗透汽化膜的开发、膜组件及系统的合理设计是实现膜技术工业化的两个关键因素.分析了渗透汽化膜用于酯化工业耦合脱水工艺的研究现状,展望渗透汽化膜在制备乳酸酯的酯化反应、双酚A的缩合反应和手性化合物的酯合成反应等方面的应用前景.     

Mathematical Modeling,Simulation, and Experimental Verification of CO2 Removal in a Turbulent Contact Absorber

A highly efficient technique of contaminant gas reduction, Turbulent Contact Absorber (TCA), is applied to CO₂ removal from a typical flue gas. Aqueous K₂CO₃ sorbent was evaluated as a regenerable sorbent for CO₂ from the flue gas. In order to identify the system, momentum and mass balance equations were written for the TCA tower. A flat plate falling film model was employed to simulate the TCA tower and the effect of turbulence was included in mass and momentum transfer coefficients. To check the accuracy of the model, a pilot scale TCA was built and operated. A Testo type gas analyzer was used to detect gas concentrations at the inlet and outlet of the rig. The model was validated successfully with pilot plant data. The effect of velocity and K₂CO₃ concentration on the TCA performance has also been carried out. It was found that the bed pressure drop increases linearly with gas velocity and then remains constant. An increase in the liquid flow rate increases liquid holdup, which leads to a rise in bed pressure drop. Higher turbulence within the TCA causes a velocity peak to shift from hypothetical gas‐liquid interface towards the falling film plate. An increase of the K₂CO₃ concentration from 1.0 g mol/L to 2.0 g mol/L was found to give an increase in CO₂ removal by about 4 %.     

丝光沸石膜渗透汽化法脱水浓缩四氢呋喃的实验研究

采用二次生长法,在无有机模板剂的条件下于a-Al2O3载体上制备丝光沸石膜. 所制丝光沸石膜用于四氢呋喃(THF)水溶液脱水浓缩,考察了操作温度、THF浓度对其渗透汽化性能的影响. 结果表明,在操作温度为60℃、THF浓度为90%(w)时,丝光沸石膜的渗透通量和分离因数分别为0.35 kg/(m2×h)和9233,渗透液水含量达99.907%(w). THF浓度在75%~97%范围内,渗透液的水含量均在99.6%以上. 对THF浓度为97.066%(w)的模拟制药废液脱水37 h后,THF浓度达99.640%.     

浅析渗透汽化膜脱水及其应用

渗透汽化作为一种节能、低能耗、绿色环保的新型膜分离技术,正受到世界范围内越来越广泛的关注和研究。文中简述了渗透汽化膜技术的基本原理、工艺流程和传质模型,介绍了影响分离效果的因素及特点;分析渗透汽化技术在有机溶剂脱水、水中脱除有机物以、有机物/有机物的分离以及化学反应中的工业应用情况,并进行经济性分析,最后展望了该技术的应用前景。     

硅橡胶膜在渗透汽化分离中的应用及研究进展

综述了硅橡胶膜在渗透汽化分离(有机废水处理、生物发酵分离)中的应用及其制备技术(无机物填充改性、共缩聚或引入侧链基团改性)的最新研究进展.     

渗透汽化膜分离技术及其在化工生产上的应用

介绍了渗透汽化膜分离技术的基本原理、特点及影响分离效果的因素,并对渗透汽化膜分离技术的进展及其在化工生产上的应用进行了介绍.     

分子筛膜渗透蒸发技术研究进展

概述了渗透蒸发膜分离过程和分子筛膜的优点,重点综述了沸石分子筛膜在渗透蒸发中的传输机理和传质模型,以及温度、压力、组成等对渗透蒸发膜分离性能的影响因素,介绍了分子筛膜渗透蒸发技术在有机溶剂脱水、水中脱除有机物和有机混合物分离等方面的应用,展望了分子筛膜在渗透蒸发膜分离技术中的发展方向。     

Experimental Study and Mass Transport Modeling of Ethanol Separation from Aqueous Solutions by Pervaporation

Abstract

Polydimethylsiloxane pervaporation membrane was employed to remove ethanol from aqueous solutions. The influences of feed flow rate, temperature, permeate-side pressure, and ethanol concentration on the membrane performance were investigated. The feed flow rate was shown to have no significant effect on either flux or ethanol selectivity whereas the feed concentration, temperature, and permeate-side pressure had highly significant effects. Sorption and desorption experiments were also performed to provide data for analysis of mass transport based on resistance-in-series model. The analysis of transport resistances revealed that the mass transport of the system was controlled by the transport resistance of components in the membrane active layer.     

渗透汽化膜技术及其在溶剂分离领域的应用

渗透汽化膜技术是一种高效节能、绿色环保的新型膜分离技术,与传统分离技术相比优势显著,使该技术成为溶剂分离领域研究的焦点。简述了渗透汽化膜技术的基本原理和工艺流程,介绍了渗透汽化膜技术在有机溶剂/水体系、有机溶剂/有机溶剂体系分离的研究应用现状,展望了渗透汽化膜分离技术的研究应用前景。     

新型渗透蒸发膜在偏二甲肼脱水中的应用前景

偏二甲肼传统的工业生产方法危险且能耗极大,渗透蒸发是一种新型的膜分离技术和清洁生产技术,受其膜材料的限制未能广泛应用,随着新型膜材料的出现打破这一瓶颈.在分析新型沸石膜用于醇/水等有机混合物脱水的应用研究基础上,讨论了将沸石膜应用于偏二甲肼脱水的可行性及待进一步研究的主要问题.     

Separation Characteristics of Dimethylformamide/Water Mixtures through Alginate Membranes by Pervaporation,Vapor Permeation and Vapor Permeation with Temperature Difference Methods

Abstract

In this study permeation and separation characteristics of dimethylformamide (DMF)/water mixtures were investigated by pervaporation (PV), vapor permeation (VP), and vapor permeation with temperature difference (TDVP) methods using alginate membranes crosslinked with calcium chloride. The effects of membrane thickness (30–90 µm), feed composition (0–100 wt%), operating temperature (30–50°C) on the permeation rates and separation factors were investigated. The permeation rate was found to be inversely proportional to the membrane thickness whereas separation factor increased as the membrane thickness was increased. It was observed that the permeation rates in VP and TDVP were lower than in PV however the highest separation factors were obtained with TDVP method. Alginate membranes gave permeation rates of 0.97–1.2 kg/m² h and separation factors of 17–63 depending on the operation conditions and the method. In addition, sorption‐diffusion properties of the alginate membranes were investigated at the operating temperature and the feed composition. It was found that the sorption selectivity was dominant factor for the separating of DMF/water mixtures.     

乙醇发酵与渗透汽化在硅橡胶膜生物反应器中的耦合强化

用硅橡胶膜生物反应器(SMBR)实验研究了发酵-渗透汽化的耦合性能。发酵微生物采用酿酒活性干酵母,所用的碳源为工业级葡萄糖。间歇发酵过程由于产物抑制作用在乙醇浓度达到90g稬-1时就趋于停滞,而经耦合渗透汽化膜分离后,发酵罐内的乙醇浓度迅速降低并维持在40g稬-1,且发酵在此浓度下可以连续稳定地进行。 在SMBR运行达到稳态后,乙醇的体积产率为1.5gL-1h-1。SMBR中所用的聚二甲基硅氧烷(PDMS)复合膜由实验室自行制备,它能稳定分离含有酵母细胞的发酵液。当发酵液中乙醇浓度为92.7~49.5g稬-1时,PDMS复合膜的总通量为1490~1164g穖-2h-1,分离因子为6.9~7.8,与分离相同进料浓度的清洁模型溶液相比分别平均高出31%和14%。乙醇发酵和渗透汽化在硅橡胶膜生物反应器中能够相互耦合并得到强化。     

硅橡胶膜生物反应器中乙醇发酵与渗透汽化的耦合

用硅橡胶膜生物反应器(SMBR)实验研究连续发酵-渗透汽化的耦合性能。发酵微生物采用酿酒干酵母,所用碳源为工业级葡萄糖。发酵过程由于产物抑制作用,在乙醇质量浓度达到73 g/L时趋于停滞,而耦合渗透汽化膜后,发酵罐内的乙醇质量浓度降低并维持在40 g/L,使发酵可以连续稳定地进行。在SMBR运行达到稳态后,乙醇的体积产率为4.02 g/(L.h)。发酵液中乙醇质量浓度维持在20~63 g/L,聚二甲基硅氧烷(PDMS)膜的总渗透通量为1 220~800 g/(m2.h),分离因子为5~9.2。与传统发酵和分离相同进料质量分数的乙醇溶液相比,乙醇发酵和渗透汽化在硅橡胶膜生物反应器中能相互耦合并得到强化。与较小规模耦合系统(发酵体积1 L和2 L)比较,性能稳定良好。     

Pervaporation separation of binary and ternary mixtures with polydimethylsiloxane membranes

This study dealt with the separation of binary water–phenol and water–methanol mixtures and ternary water–phenol–methanol mixtures by pervaporation (PV) with polydimethylsiloxane (PDMS) membranes. The effects of the operating conditions (feed temperature, feed concentration, and feed flow rate) on the separation performance for binary mixtures were investigated. An increase in temperature or concentration increased the total permeation flux and decreased the organic separation factor. In other words, an increase in the temperature or feed organic concentration increased the water flux more significantly than the organic compound flux, which resulted in a separation factor reduction. Also, an increase in the feed flow rate increased the total flux and separation factor because the boundary layer effects diminished. The vapor–liquid equilibrium separation factor (α_VLE) and pervaporation separation factor (α_PV) values for the PDMS membrane were calculated, and this showed that α_PV for the water–phenol mixture was greater than α_VLE. This means that the membrane was highly efficient for the PV separation of phenol from dilute aqueous solutions relative to the separation of methanol. This was due to the fact that phenol has a higher solubility parameter than methanol in silicone membranes. To study the effect of a third component on membrane performance, PV experiments were also carried out with water–phenol–methanol mixtures. The results for total permeation flux and the phenol separation factor for PDMS membranes in contact with water–phenol–methanol ternary mixtures are similar to those in contact with water–phenol binary mixtures. The phenol separation factor of the membrane in contact with the ternary mixture was slightly lower than that in contact with the binary mixture. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

渗透汽化膜处理低浓度甲醇废水的研究进展

由于石油资源短缺和我国新能源战略的进一步实施,甲醇被认为是石油替代品之一。随着甲醇需求量的增加,其生产过程中产生的含醇废水也急剧增加,由此造成低浓度甲醇废水污染日趋严重。渗透汽化膜分离技术被认为是治理低浓度甲醇废水的较好方法。简要介绍了渗透汽化膜处理低浓度甲醇废水的研究进展,并对其未来的研究趋势和发展前景进行了展望。     

聚酰亚胺渗透汽化膜改性研究进展

详细综述了用于渗透汽化分离的聚酰亚胺膜的改性研究进展,重点评述了共聚（改变主链结构、侧基结构和引入特殊功能性单体）、填充（无机物填充和有机物填充）、交联、共混以及表面改性5种改性方法,包括其反应原理、设计思路以及对聚酰亚胺膜分子结构和分离性能的影响等。同时通过比较不同改性方法的研究结果,分析了几种改性方法在渗透汽化膜分离方面的优点和不足。在此基础上,对聚酰亚胺渗透汽化膜的改性方法发展方向和研究前景进行了总结。     

One‐Dimensional Modeling and Simulation of Bubble Column Reactors

Reactor models that feature a practical way to design bubble columns on the semi‐industrial or even industrial scale have been published only rarely in the usual scientific literature. Creating a one‐dimensional model in the equation‐oriented simulation software ASPEN Custom Modeler? (ACM), one can reach a compromise between model precision and modeling – i.e. computational power – based on correlations selected specifically for the application in question. The model quantitatively describes, with sufficient accuracy, the processes in a bubble column reactor. The paper discusses investigations for designing a pilot plant reactor for hydrogenating 2‐ethylhexanal as an example of its application. Geometry and operating conditions were optimized, and the results are shown in the form of spatially resolved reaction and temperature profiles.     

Pervaporation separation of n‐heptane/organosulfur mixtures with PDMS membrane: Experimental and modelling

In this paper, polydimethylsiloxane (PDMS) pervaporation membrane was employed to simulate the desulfurization process of gasoline where n‐heptane was selected to stand for gasoline. A modified solution–diffusion model is proposed to account for the mass transport of penetrants in the polymer membrane. In the model, the group contribution method (the UNIFAC‐ZM model) is applied to calculate the activity of penetrants in the polymer membrane, and the free volume theory with some modifications is employed to describe the diffusion behaviour of the penetrants. The effects of operating temperature and feed concentration on pervaporation properties were investigated to validate the model. It has been shown that the results predicted by the solution–diffusion model are in good agreement with the experimental values.