电渗析-真空膜蒸馏集成膜法回收离子液体

为了达到最大限度回收离子液体循环再利用的目的,用电渗析-真空膜蒸馏集成膜法浓缩低浓度质量分数(下同)为1%~5%的离子液体水溶液,实现了有效可操作的膜集成浓缩过程控制。分析了膜集成过程中电渗析施加电压、料液初始浓度和料液体积比等操作参数对优化工艺的影响,获得了此电渗析过程的最高浓缩浓度。当电渗析可浓缩[AMIM]Cl至最大浓度时,即可切换至真空膜蒸馏过程深度浓缩,最终可将[AMIM]Cl水溶液浓缩至48.2%。     

超声波强化真空膜蒸馏的试验研究

对超声波强化真空膜蒸馏进行了试验研究，结果表明：超声波强化能较显著的提高蒸馏通量，在本实验范围可将真空膜蒸馏系统的蒸馏通量提高31％；超声波功率越大，温度越低，流速越小，强化效果越明显；膜器件的外壳材料对强化效果也有较大影响。     

真空膜蒸馏分离乙醇溶液试验研究

采用真空膜蒸馏装置处理乙醇溶液,探究采用真空膜蒸馏浓缩高浓度乙醇溶液时的膜蒸馏效能及可行性,考察进料温度、进料乙醇浓度等因素对膜蒸馏效能的影响。结果表明,温度能显著提高膜通量,当温度从50℃上升至75℃时,膜通量从3.90 kg/(m²·h)增加至19.90 kg/(m²·h),乙醇通量从1.84 kg/(m²·h)增加到9.17 kg/(m²·h);随着进料乙醇浓度的增加,膜通量与乙醇通量均升高。在浓缩时间为2.0～2.5 h时,高浓度乙醇溶液的膜蒸馏浓缩分离过程运行稳定,在浓缩时间超过2.5 h后,出水通量有增加的趋势,出水乙醇质量分数和分离比有下降的趋势,且膜面上出现浸润点,经试验分析可知膜发生浸润现象是由于管道和膜组件的材质在高温、高浓度下的乙醇溶液中不稳定所致,后续可应用其他材质的膜组件以及耐高温的新型膜材料进行处理。     

离子液体回收的研究进展

离子液体作为一种绿色溶剂可以有效地解决目前存在的能源和环境问题。由于离子液体相对于其它有机溶剂具较好的化学稳定性,使其在众多的研究领域受到越来越多的关注。但是离子液体存在着合成成本较高、回收难度较大等技术瓶颈问题,因而阻碍了它的广泛应用。而安全、有效地回收离子液体能够解决这一难点。离子液体的回收方法有减压蒸馏、膜分离、盐析、液液萃取等。离子液体的有效回收可以促进化学合成、纤维素提取等领域的快速发展。     

真空膜蒸馏过程膜参数模拟计算

为了研究膜材料对透过通量的影响,文章建立了真空膜蒸馏过程的微观传热传质模型,并利用该模型对文献中的实验数据进行了模拟,得到了比较满意的结果。进而对不同条件下膜的长度、厚度、内径以及曲折因子、传质系数进行了模拟计算,并讨论了不同膜参数对膜透过通量的影响,为真空膜蒸馏过程中膜材料的选取及合理利用提供一定的理论依据。     

离子膜法烧碱生产中废水回收利用

介绍了停车洗槽水、树脂塔酸碱再生水、泵用机封冷却水等的回收利用措施,实施后,节约去离子水价值6.5万元/a,回收废碱价值28万元/a.     

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.     

真空膜蒸馏用于多元醇水溶液分离的研究

利用自制的聚丙烯中空纤维膜,采用真空膜蒸馏法对1,2-丙二醇水溶液的分离进行了研究.考察了料液入口温度、冷侧真空度、料液流量以及料液浓度对膜通量和截留率的影响.结果表明,膜通量随料液入口温度、冷侧真空度及料液流量的增加而增加,随料液浓度升高而下降.截留率随料液入口温度、冷侧真空度和料液浓度的增加而下降,料液流量的变化对截留率没有明显的影响.本试验条件下最佳截留率可达100%,表明利用真空膜蒸馏技术可有效实现多元醇水溶液分离.     

混合离子液体催化反应精馏合成乙酸正己酯

离子液体催化反应精馏是提高酯交换平衡反应转化率的一种绿色有效方法。以离子液体1-丙基磺酸-3-甲基咪唑三氟甲烷磺酸盐（［PSO₃HMIm］［OTf］）和离子液体1-辛基-2,3-二甲基咪唑双（三氟甲烷磺酰）亚胺盐（［OMMIm］［Tf₂N］）的混合物作为乙酸甲酯和正己醇进行酯交换反应合成乙酸正己酯的催化剂,测定了酯交换反应动力学。探讨了混合比、反应温度、反应物初始摩尔比、催化剂浓度对反应速率和乙酸甲酯转化率的影响,考察了催化剂的回收性能。利用实验数据回归得出混合离子液体催化酯交换反应动力学方程。在反应动力学的基础上进行了乙酸甲酯和正己醇的酯交换反应精馏流程模拟,分析了理论板数、回流比、进料位置及反应段塔板数、催化剂用量、持液量等参数对反应精馏塔的影响。在优化的操作条件下,获得纯度为0.9993的乙酸正己酯产品。     

Extractive distillation with ionic liquids: A review

Extractive distillation is commonly used for the separation of azeotropic or close‐boiling mixtures in the chemical industry. During the past decade, the use of ionic liquids (ILs) as entrainers has received considerable attention due to their unique advantages when applied in extractive distillation. This work is devoted to providing an easy‐to‐read and comprehensive review on the recent progress made by chemical engineers, focusing on the issues of predictive thermodynamic models, structure‐property relations, separation mechanisms, and process simulation and optimization. This review spans from the molecular level to the industrial scale, to provide a theoretical insight into the molecular interactions between ILs and the components to be separated. Moreover, a comprehensive database on the vapor–liquid equilibria and activity coefficients at infinite dilution concerning ILs is provided as Supporting Information. Concluding remarks are made on the unsolved scientific issues with respect to this promising special distillation technology. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3312–3329, 2014     

电渗析法制备水溶性离子液体

以1-乙基-3-甲基咪唑四氟硼酸盐（［EMIm］BF₄）的制备为例,对四隔室电渗析法制备水溶性离子液体进行了研究。分别考察了操作电压、进料浓度和离子交换膜种类对平均电流效率、能耗和收率3个电渗析过程性能参数的影响。实验结果表明,相比于传统的化学合成法制备离子液体,采用四隔室电渗析法制备水溶性离子液体具有反应条件温和（室温下反应）、反应时间短、反应无须传统有机溶剂（水作反应溶剂）和产物纯度高（最高可达98％）的优点。     

离子液体支撑液膜的研究及应用进展

回顾了目前为止离子液体支撑液膜的制备方法、离子液体结构、支撑膜结构对离子液体支撑液膜稳定性的影响因素,介绍了其在有机物分离、气体分离、分离反应耦合方面的应用。由于传统的单元操作很难满足污染和对过程集成的要求,对离子液体支撑液膜在未来实现清洁生产的发展方向进行了展望。     

Structure optimization of tailored ionic liquids and process simulation for shale gas separation

Shale gas, as a potential substitute for energy source, requires important processing steps before utilization. The most common separation technology applied is distillation, which is energy-intensive. With good stability, non-volatility, and tailored properties, ionic liquids (ILs) are regarded as novel potential solvents and alternative media for gas absorption. Therefore, a new strategy for hybrid shale gas separation processing, where IL-based absorption together with distillation is employed for energy-efficient and cost-economic gas processing, is developed. In this work, a three-stage methodology for shale gas separation process is proposed: IL screening, where a systematic screening method with two options (database screening and computer-aided design based on universal quasichemical functional-group activity coefficient model) is established; suitable ILs are selected as promising candidates; process design and simulation, where separation schemes and important design issues in the IL-based processes are determined; and, process evaluation, where the performance of the final separation process is evaluated and verified.     

Efficient recovery of ionic liquid by electrodialysis in the acid hydrolysis process

Electrodialysis (ED) has been recently known as a highly effective technique to remove and recover ionic liquids from aqueous solution. When a conventional electrolyte solution for the ED process containing Na₂SO₄ was used, a recovery ratio of an acidic IL, 1-butyl-3-methylimidazolium hydrogen sulfate ([Bmim][HSO₄]), was 90%. On the other hand, the value clearly increased to 96% when we employed [Bmim][HSO₄] as the electrolyte solution. In an acid hydrolysis of bagasse using the IL under microwave irradiation, the recovery ratio maintains 96%, irrespective of reaction time. This demonstrates the applicability of the proposed ED system in biomass processing.     

离子液体在膜分离过程中的应用研究进展

介绍了离子液体(ionic liquids)是由有机阳离子和有机或无机阴离子构成的、在室温或室温附近温度下呈液体状态的盐类,是新兴的可替代挥发性有机化合物的绿色溶剂。阐述了离子液体具有熔点低、不易燃、低挥发性(蒸气压接近于零)、高导电能力、电化学窗口宽、可调节性强等独特性质;在二氧化碳、二氧化硫等酸性气体以及苯、环己烷等有机溶剂分离过程中有广泛应用前景。同时,介绍了含有双键等可聚合基团的一类离子液体-聚离子液体[poly(ionic liquid)s,PILs]在二氧化碳吸收方面有特殊表现,指出聚离子液体与聚偏氟乙烯(PVDF)共混得到的薄膜材料具有高稳定性、高机械强度以及高电导率,对于缓解能源匮乏以及环境污染等具有重大意义。     

精馏-膜分离技术集成过程研究进展

精馏-膜分离集成过程与传统精馏工艺相比,因其具有明显节能降耗的经济性优势,故工业应用日渐增多,所以对其进行全面研究更有理论和实际意义。本文介绍了膜分离的机理模型,根据膜的亲水性和亲有机性对膜材料进行分类,总结了精馏-膜分离集成过程的理论研究方法,并分别从脱水和脱有机物两方面介绍了精馏-膜分离集成过程的主要实验研究及工业应用研究进展。通过对现有研究分析发现,目前该集成过程在膜材料和集成优化理论研究方面存在一定局限性,使其未能在工业上得以广泛推广应用。基于上述全面分析,提出了一定改进思路。     

A method for the design of distillation systems aided by ionic liquids

Ionic liquids (ILs) have recently been considered for several applications in chemical processes. Particularly, as they promote an evident salting-out effect over vapor–liquid equilibrium properties and integrate the advantages of a liquid entrainer with the benefits of a solid salt, the use of ILs for the ethanol–water separation has gained wider interest. In this work, a design method for distillation systems aided by ILs is presented. The method is based on tray-by-tray calculations from the outside to the inside of the column, and the feed stage is determined by using a minimum distance concept. The method is illustrated with an ethanol dehydration design. An analysis on the effect of ILs on the column composition profiles is also carried out. The method is shown to provide an effective tool for the conceptual design of these types of systems.     

Research progress of high-efficiency membrane distillation crystallization process

The global shortage of water resources and environmental pollution has made the demands for industrial wastewater treatment, seawater desalination, and comprehensive utilization of high-value solutes increasingly urgent. Membrane distillation crystallization process cannot only make full use of low-quality heat sources, achieve high-purity water-solvent separation, but also achieve salt crystallization preparation, which is of great significance for achieving zero liquid discharge and synergistic efficiency in the separation process. At the same time, membrane distillation crystallization process can also be coupled with multi-stage flash evaporation, multi-effect distillation, nanofiltration, forward infiltration, reverse osmosis and other processes to further improve the overall separation efficiency. In addition, it also has a positive impact on regulating the external morphology of the crystal, preparing crystal products with relatively concentrated crystal size distribution and good flowability. Based on this, this article has discussed several aspects of membrane distillation crystallization principles, process control mechanisms and innovative process applications, and looking forward to the key issues and development trends of membrane distillation crystallization technology in the fields of efficient separation and precise control of the crystallization process.