真空膜蒸馏技术在水处理中的应用进展

真空膜蒸馏（VMD）过程是一种新型的膜分离技术,本文综述了真空膜蒸馏技术的工作原理、特点,介绍了真空膜蒸馏在海水淡化浓盐水、处理工业废水、中药浓缩中的研究应用,展望了这种新型水处理技术的应用前景。     

新型盐水浓缩技术在离子膜烧碱生产中的应用研究

阐述了LEMON~膜蒸馏技术用于盐水浓缩的设计原理及在离子膜烧碱装置中的应用研究。     

膜蒸馏技术处理含碳酸钾废水初步研究

介绍了膜蒸馏技术的原理、优点及其应用领域。采用自制板式直接接触式膜蒸馏器和真空减压式膜蒸馏器，研究了含碳酸钾废水溶液的浓缩结晶过程。结果表明，膜蒸馏技术处理含碳酸钾废水效果良好，既回收了碳酸钾，又获得了达标排放的清水。     

减压膜蒸馏法浓缩氧化铝碳分母液的可行性

对减压膜蒸馏法浓缩氧化铝碳分母液的可行性进行了研究,系统考察了料液温度、减压侧压力及料液流速等操作条件对水蒸馏通量的影响。结果表明,蒸馏液的pH值约13,减压膜蒸馏对N2AlO2、NaOH及Na2CO,等非挥发性组分的截留率较高,能达到有效浓缩的目的;在实际操作过程中,温度越高、减压侧压力越低及料液流速越大,水蒸馏通量越大。     

真空膜蒸馏技术在盐水淡化中的应用

真空膜蒸馏技术是一种新型的膜分离技术,真空膜蒸馏技术具有截留率高、成本低、设备简单、操作容易、能耗低等优点。本文综述真空膜蒸馏技术盐水淡化中的影响因素、机理以及存在的问题,并指出真空膜蒸馏技术在盐水淡化中的应用前景。     

真空膜蒸馏淡化盐水的现状及发展

真空膜蒸馏技术(VMD)是一种以蒸汽压差为推动力的新型膜分离技术,具有截留率高、操作压力低、设备简单、能耗低等优点.本文综述了真空膜蒸馏技术淡化盐水的研究现状和应用效果,分析了影响分离性能的相关因素,指出了真空膜蒸馏过程目前存在的问题,进而指出真空膜蒸馏技术在淡化盐水方面的研究发展趋势.     

膜蒸馏过程强化及优化技术研究进展

膜蒸馏作为一种新型的膜分离技术,具有脱盐率高、可处理高浓度原料液等技术优势,近年来引起学术界及工业界的广泛关注.膜蒸馏技术可被应用于海水淡化,工业废水/苦盐水脱盐及糖、盐、果汁、有机/无机酸、碱液等的浓缩过程.但由于当前膜蒸馏能耗及成本较高,一定程度上限制了该技术的工业化.本文重点介绍了可用于强化膜蒸馏过程和优化该过程能量利用的方法及研究进展,主要包括膜材料和膜制备方法/工艺的进展、膜蒸馏过程操作条件的优化、改进膜组件和辅助装置的应用、太阳能和低品位热源的使用、蒸发冷凝潜热的回收以及耦合其他分离过程的复合膜蒸馏系统,同时分析了膜蒸馏技术处理高盐工业废水的应用前景,最后探讨和总结了膜蒸馏过程强化及优化的研究方向,为该技术的进一步发展提供了科学性指导.     

减压膜蒸馏技术及其在环保领域中的应用

减压膜蒸馏是一种新型的膜分离技术。本文主要对减压膜蒸馏过程的机理、用膜材料、提高蒸馏性能的措施及在环保中的应用进行评述。     

减压膜蒸馏法稀碱液浓缩过程研究

以聚偏氟乙烯疏水膜为材料,采用减压膜蒸馏技术在较高真空度下浓缩硫化钠溶液,研究了各种条件对膜通量的影响.结果表明,当进料温度80℃、真空度为80kPa、流速为0.99m·s~(-1)时,质量分数4.6%的硫化钠溶液VMD膜通量为23.7 kg·m~(-2)·h~(-1);连续运行时,将稀碱液浓缩5倍后,膜通量仍维持在10.6kg·m~2·h~(-1),用稀盐酸清洗后膜通量恢复到初始值的95.6%;浓缩过程产水电导维持在10μS·cm~(-1)以下,脱盐率大于99.99%.     

萃取-膜蒸馏法处理钛白废酸的研究

提出了三异辛胺-仲辛醇-航空煤油体系萃取硫酸与减压膜蒸馏浓缩相结合的钛白废酸治理新方案。对萃取工艺参数、膜蒸馏浓缩稀硫酸的基本规律及萃取回收硫酸的浓缩程度进行了研究。结果表明:1.49mol·L-1的钛白废酸经8级萃取和6级反萃取,酸回收率可达92.15%,稀硫酸浓度为1.21mol·L-1,再经减压膜蒸馏浓缩可得到10.82mol·L-1(质量分数67.3%)的硫酸,达到了返回钛白生产循环使用的要求。     

Vacuum membrane distillation simulation of desalination using polypropylene hydrophobic microporous membrane

Numerical simulation is an effective method to get the optimal operating parameters in the chemical engineering process. In this work, the transport mechanism of vacuum membrane distillation (VMD) process was simulated and predicted by mathematical model, which was established based on the convective heat transfer coefficient, and 0.5M aqueous NaCl solution was concentrated with isotactic polypropylene (iPP) hydrophobic microporous membrane prepared via thermally induced phase separation (TIPS) in the VMD process. The as‐presented mathematical model simulated the effects of different operating parameters on the VMD performances for aqueous NaCl solution, such as feed temperature, feed flow rate, absolute pressure of membrane permeate side, temperature coefficient, membrane thickness, and porosity. A comparison between experimental data and simulated data was also considered to verify the proposed mathematical model. Additionally, the salt rejection of aqueous NaCl solution production water in VMD was higher than 99.9%. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41632.     

膜蒸馏技术研究及应用进展

膜蒸馏作为一种新型分离技术,具有操作温度低、设备简单、脱盐率高等特点,在海水淡化、苦咸水脱盐、果汁浓缩等过程具有良好的应用前景。本文简述了膜蒸馏的工作原理、特点和膜材料的制备方法,指出当前膜材料的研究方向。综述了直接接触式、气隙式、真空式和气扫式4种基本膜蒸馏形式和几种改进的膜蒸馏形式的传热传质原理、研究现状和发展方向。重点介绍了可再生能源以及工业低温余热驱动膜蒸馏的技术特点、研究现状和应用,包括太阳能光伏/光热驱动膜蒸馏技术、太阳能热泵耦合驱动膜蒸馏技术、太阳池膜蒸馏技术、地热能梯级利用驱动膜蒸馏技术和低温余热驱动膜蒸馏技术等,并指出其发展方向。最后,探讨了膜蒸馏技术亟待研究和解决的问题,为该技术的进一步发展提供参考。     

Vacuum membrane distillation processes for aqueous solution treatment—A review

The current applications of vacuum membrane distillation (VMD) process for various industrial aqueous solutions have been thoroughly reviewed. The applications of VMD can be grouped into three major processes: the single component transport process, the binary component transport process and the multicomponent transport process. The porous and hydrophobic membrane in the VMD system serves as a physical support for the liquid–gas interface and does not allow one of the phases to disperse into the other. The membrane provides an efficient separator for the phase-change process. The use of the correct membrane can offer a high production rate and a high separation factor at low temperatures. VMD, an alternative separation technology with applications in desalination, concentration, organic extraction and dissolved gas removal, can compete with conventional liquid–gas separation systems. The present paper critically reviewed VMD technology; the important components of the scope of this review included applications and processes, membrane modules, heat and mass transfer, model development, membrane, process conditions, fouling, energy consumption and production cost. Finally, the potential for future research as a requisite for VMD industrialisation was suggested.     

Effect of ethylene vinyl acetate content on the performance of VMD using HDPE co-blending membrane

Membranes were fabricated with high-density polyethylene(HDPE) and ethylene vinyl acetate(EVA) blend through thermally induced phase separation and were then used for vacuum membrane distillation(VMD).The membranes were supported by nonwoven polyester fabric with a special cellular structure. Different membrane samples were obtained by adjusting the polymer concentration, HDPE/EVA weight ratio, and coagulation bath temperature. The membranes were characterized by scanning electron microscopy(SEM) analysis, contact angle test, and evaluation of porosity and pore size distribution. A series of VMD tests were conducted using aqueous NaCl solution(0.5 mol·L~(-1)) at a feed temperature of 65 ℃ and permeate side absolute pressure of 3 kPa. The membranes showed excellent performance in water permeation flux, salt rejection, and long-term stability. The HDPE/EVA co-blending membranes exhibited the largest permeation flux of 23.87 kg·m~(-2)·h~(-1) and benign salt rejection of ≥99.9%.     

减压膜蒸馏法处理多酚类制药废水的研究

采用绿色水处理技术——减压膜蒸馏(VMD)法处理多酚类制药废水并从中回收乙醇，探讨了实验条件对膜分离性能的影响，在最佳工艺条件下，回收乙醇的质量分数达34．5％，多酚类混合物的截留率99．67％。理论分析和实验数据表明，作为一种新型的绿色水处理技术，VMD具有膜通量大，成本低，分离效果好等优点，可在工业化有机溶剂废水的处理及回收溶剂等方面发挥重大作用。     

Threshold Flux for Vacuum Membrane Distillation to Concentrate Herbal Aqueous Solutions

Vacuum membrane distillation (VMD) is considered an effective method for concentration of herbal aqueous solutions (HAS). However, membrane fouling and flux decline are complex problems in such concentration processes. The concept of threshold flux was proposed for optimizing the membrane process. Whether it is useful for guiding optimization of the VMD process on HAS concentration needs further investigation. The Semen Raphani aqueous solution (SRAS) was taken as an example to investigate the membrane flux behavior during SRAS concentration by VMD. The results confirmed that the threshold flux concept is applicable to concentrate HAS by VDM. At or below the threshold flux, the total resistance was independent of the flux, while above it membrane fouling increased with higher membrane flux. Moreover, limiting the flux should be avoided in the membrane process because of strong fouling and flux decline.     

Simulation of Membrane Distillation for Purifying Water Containing 1,1,1‐Trichloroethane

Vacuum membrane distillation is modeled for the purification of water containing organic matter. The separation medium is a hollow‐fiber membrane contactor that is simplified to a two‐dimensional structure with a single porous membrane wall. The model considers the transport phenomena of a vacuum membrane distillation system in porous media, in which the aqueous volatile organic solution was considered as an incompressible and steady fluid. The numerical simulation of the two‐dimensional model of vacuum membrane distillation for an aqueous solution of 1,1,1‐trichloroethane was established under steady state. The effects of the bulk feed temperature and the feed flow rate on the percentage of 1,1,1‐trichloroethane removal from an aqueous solution are discussed.