水杨醇的萃取-反萃取分离研究

水杨醇及其钠盐是合成医药和农药的重要中间体[1～4],其中水杨醇钠的应用尤为广泛.水杨醇在水中溶解度较大,需用萃取方法分离.在实验室里一般都采用乙醚作萃取剂,但在工业生产中,则不宜采用.原因是:1.乙醚易燃、易爆,不利于安全生产;2.乙醚易挥发、损耗大、污染环境,生产成本高.鉴于此,我们选用甲基异丁基酮替代乙醚作工业萃取剂,并研究了萃取工艺条件.     

新型改性氧化铝膜蒸汽渗透分离醇水混合物

引言工业生产中经常会遇到醇水混合物的分离问题．膜分离技术与传统的分离过程相比,具有设备简单、操作容易、能耗低和无污染等优点,因此,用经济的膜技术进行醇水混合物分离和浓缩的研究具有广阔的应用前景．其中,采用气相进料的蒸汽渗透膜技术在有机溶剂-水混合物的分离方面显示出明显的竞争优势［1-3］．已报道的用于醇水混合物分离的膜以有机聚合物膜居多．有机膜虽然选择性较高,但其渗透通量却难以满足实际生产的需要．无机陶瓷膜通量大,其选择性则取决于膜孔的大小与结构．为了提高陶瓷膜的选择性,涌现出许多减小膜孔径和改善膜…     

分子筛膜-精馏耦合用于费托合成水相副产物混合醇回收的工艺流程模拟

费托合成油水相副产物混合醇的回收多采用萃取精馏的分离方法,此方法需要配置7个精馏塔和5路循环回路。通过分析发现,流程冗长的关键因素在于混合醇中除甲醇外各个组分均与水产生共沸,而分子筛膜渗透汽化技术不受汽液平衡的限制,因此可以利用分子筛膜渗透汽化技术将混合醇中的水分先脱除,然后再利用精馏技术对混合醇各组分进行分离。本文完成了精馏-膜分离耦合工艺分离混合醇的全流程模拟,并与传统的萃取精馏工艺流程进行对比。精馏-膜分离耦合工艺大幅简化了原有萃取精馏工艺流程,整体能耗降低30%。并根据此流程在陕西延长石油（集团）有限公司建成了国内第一套膜分离-精馏耦合工艺的1000t/a低碳混合醇回收和分离的工业示范装置。     

微孔γ－Al2O3膜的蒸汽吸附特性

引　言蒸汽渗透 (ｖａｐｏｒｐｅｒｍｅａｔｉｏｎ)是膜分离混合蒸汽的有效技术之一 ,它采用气相进料 ,过程中的浓差极化现象较弱 ,并且在分离过程中不需提供额外的热量以维持被分离物流的温度 ,避免了渗透蒸发(ｐｅｒｖａｐｏｒａｔｉｏｎ)过程设备复杂的缺陷 .这使得蒸汽渗透过程可以很便利地与传统的蒸馏过程相耦联 .因而 ,利用蒸汽渗透膜技术分离有机溶剂 /水混合蒸汽的研究日益受到关注 .文献 [1,2 ]报道了γ -Ａｌ2 Ｏ3膜能有效地分离醇 /水、酮 /水混合蒸汽 .膜对有机蒸汽的吸附性能与蒸汽渗透的分离效果密切相关 ,同时也是膜传质机…     

NaA分子筛膜的制备及其用于醇水分离的研究进展

综述了NaA分子筛膜的制备方法及NaA分子筛膜在醇水分离应用中的最新研究进展和发展趋势.主要介绍了水热合成法、晶种法和微波加热法.总结了NaA分子筛膜制备过程的影响因素,包括支撑体及合成条件对分子筛膜醇水分离性能的影响.介绍了一些国外NaA分子筛膜工业应用情况.最后提出了我国NaA分子筛膜醇水分离方面工业应用的前景和需要进一步解决的问题.     

化工分离技术最新研究进展

任何一个石油化工、医药化工、生物化工等都离不开分离过程[1]。为了适应生产的需要,传统的分离技术如蒸馏、萃取、结晶、吸附等也在结合着新的科技的发展不断地改进,自膜分离技术以来又逐渐衍生出了各种各样的分离技术如膜萃取、膜蒸馏等。还有新型的泡沫分离法、分子印记分离法等也逐渐进入了生产中。     

浊点萃取技术及其在分离过程中的应用

浊点萃取(CPE)技术是一种新型的环境友好的溶质富集和分离方法,其应用领域已经自最初的样品分析扩展到大规模的分离过程如水处理和生物产品提取.与传统的溶剂萃取技术相比,该技术具有快速、高效、简便、无需大量有机溶剂等特点.本文简要介绍了浊点萃取技术机理研究的新进展和近期报道的分离过程中的应用.     

醇-水体系汽液相平衡的盐效应及其在精馏过程的应用

加盐精馏是一种新型分离技术。本文讨论了盐对醇-水体系汽液相平衡的影响,并在理论上进行了探讨。进而论述了加盐精馏在醇-水体系分离过程的应用,包括溶盐精馏、加盐萃取精馏和加盐反应萃取精馏等,并讨论了它们的优缺点。最后,展望了加盐精馏分离醇-水体系的发展。     

结晶分离技术新进展

概述了结晶分离理论和模拟优化的发展,综述了冷却剂直接接触冷却结晶、反应结晶、蒸馏-结晶耦合、氧化还原-结晶液膜、萃取结晶、磁处理结晶等结晶分离方法.合理设计结晶器及结晶工艺是实现结晶分离工业化的可靠保证,对降膜结晶装置、Bremband结晶工艺和板式结晶器进行评价.指出今后需深入进行新型结晶分离装置与工艺、工艺的工业化、结晶过程传热传质机理方面的研究.     

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.     

Effects of baffles on separation of aqueous ethanol solution with hollow fibers

The effects of baffles on the operation and mass-transfer characteristics in novel hollow fiber membrane contactor used in distillation were investigated. Hollow fiber membranes, coated with a 7 μm polydimethyl-siloxane, were operated as structural packing in the separation of ethanol-water solutions. The parallel flow mode was chosen for separation due to the stronger driving force of the concentration difference, in which liquid flows through the lumens of the fibers and vapor flows countercurrent-wise outside the fibers. Two baffles were installed on the shell side of the membrane contactors to enhance separation, which had a round shape with a semi-lunar hole. The results show that both baffled and unbaffled membrane contactors gave better, more productive separations than traditional packing in distillation, such as the excellent Sulzer Gauze BX structured packing. The baffled membrane contactors performed better than unbaffled ones, especially at high vapor velocities. The minimal HTU of membrane contactor with baffles could reach as low as 4.5 cm, and almost all the contactors could work well above the limit where flooding normally occurs in conventional cases. Theoretical analysis predicted that baffles helped membrane module to obtain a higher masstransfer coefficient and a smaller mass-transfer resistance. Finally, theoretical mass-transfer coefficient and experimental value were compared as well as the contribution of each individual mass-transfer coefficients among liquid, gas and membrane.     

中空纤维PVA/PAN复合膜填料的乙醇水溶液精馏性能

以乙醇/水溶液为分离对象,中空纤维PVA/PAN复合膜作为精馏填料,考察了不同膜组件的传质分离效率。实验结果表明:各种组件的分离效率均随塔釜加热功率的增加而减小;和大多数中空纤维膜接触器一样,其总传质系数Ky随中空纤维膜组件填充密度φ的增加而减少;相比于传统精馏填料而言,用中空纤维膜做精馏填料分离乙醇水溶液的分离效果更好,可以在常规填料不能操作的液泛线以上进行操作。当塔釜加热功率为120 W,45根中空纤维膜封装在内径为1.6 cm玻璃管中的传质单元高度(HTU)为5.64 cm。     

填充密度对中空纤维膜接触器精馏过程壳程传质的影响

探讨了填充密度对新型聚丙烯中空纤维膜接触器精馏过程中壳程传质的影响。中空纤维膜接触器在填充密度为4.7%、9.5%、19%时均可在远离常规填料液泛线以上的气速范围操作。低填充密度下,壳程的Sherwood数理论值大于实验值,但填充密度较高时,实验值大于理论值。高Reynolds数有利于壳程传质,低填充密度时的Sherwood数高于高填充密度时。随着F因子逐步增大,壳程气相传质阻力随之变小,且膜接触器的填充密度越高,气相传质阻力越大。3种不同填充密度膜接触器的气相总传质系数随着接触器填充密度的增大而迅速减小,由391.84×10^-5 m·s^-1降低为83.28×10^-5 m·s^-1。     

膜接触器及其相关过程在废水处理中的应用

膜接触器是一种通过膜作为两相之间的分离界面而实现相间传质的新型杂化膜过程,具体应用形式包括膜蒸馏、膜萃取、膜吸收、膜结构填料等.膜接触器使用微孔中空纤维膜将两流体分隔开,膜孔为两流体之间提供传质的场所.与传统接触分离器相比,新兴的膜接触器拥有分离效率高、工作范围宽、两相流速可单独控制以及结构紧凑等诸多独特的优点.文章着重于膜接触器及其相关过程在废水处理领域的最新研究成果和进展,具体分析比较了上述几种膜接触器的结构、工作原理和操作特点,充分展示了膜接触器在废水处理以及化工、医药、食品等领域特种分离中的广阔应用前景.     

膜结构填料的物化特性对精馏分离异丙醇/水体系的影响

选用了三种不同材料的中空纤维膜(PP,PS和PES)构建新型膜接触器结构填料,并对异丙醇/水体系进行了精馏分离过程研究.在新型膜接触器中,液相和气相分别在管程和壳程进行逆向流动.实验结果表明:三种结构填料对异丙醇/水体系的分离效果依序为PES>PP>PS.不同材料的中空纤维膜作为结构填料对异丙醇/水溶液体系的分离效率均...     

CFD Simulation and Modeling of Membrane‐Assisted Separation of Organic Compounds from Wastewater

The extraction of volatile organic compounds (VOC) from water in porous hollow fibers was simulated with toluene, a hazardous material. The system to be simulated included a VOC stream and air as stripping gas, which were contacted using a porous hollow‐fiber membrane contactor. To model the process, the contactor was considered as three compartments, including shell side, porous membrane, and tube side. The model equations were derived and solved using computational fluid dynamics of momentum and mass transfer in all zones of the contactor. The profiles of concentration and pressure were obtained for the VOC in the hollow fibers.     

Hollow fiber membrane contactor as a gas-liquid model contactor

Microporous hollow fiber gas-liquid membrane contactors have a fixed and well-defined gas-liquid interfacial area. The liquid flow through the hollow fiber is laminar, thus the liquid side hydrodynamics are well known. This allows the accurate calculation of the fiber side physical mass transfer coefficient from first principles. Moreover, in the case of gas-liquid membrane contactor, the gas-liquid exposure time can be varied easily and independently without disturbing the gas-liquid interfacial area. These features of the hollow fiber membrane contactor make it very suitable as a gas-liquid model contactor and offer numerous advantages over the conventional model contactors. The applicability and the limitations of this novel model contactor for the determination of physico-chemical properties of non-reactive and reactive gas-liquid systems are investigated in the present work. Absorption of CO₂ into water and into aqueous NaOH solutions are chosen as model systems to determine the physico-chemical properties for non-reactive and reactive conditions, respectively. The experimental findings for these systems show that a hollow fiber membrane contactor can be used successfully as a model contactor for the determination of various gas-liquid physico-chemical properties. Moreover, since the membrane contactor facilitates indirect contact between the two phases, the application of hollow fiber model contactor can possibly be extended to liquid-liquid systems and/or heterogeneous catalyzed gas-liquid systems.     

气/液膜接触分离过程及其膜材料研究

新型气液膜接触器是很多具有共同特点膜过程的总称,它使用高分子膜将两流体分隔开,膜孔为两流体提供有效传质的场所,与传统分离器相比具有许多独特的优点,日益成为分离科学研究的热点。简述膜接触器在不同气/液分离体系中的应用,针对膜吸收、膜蒸馏、膜结构填料等三种典型的气/液界面膜接触分离过程,从结构、膜材料、传质、分离效率等方面详细进行了分析和比较。着重介绍了近年来相关领域膜材料学的研究进展,如高分子膜材料、成膜方法以及膜材料的改性方法(等离子体改性法、紫外辐照法和表面涂覆改性法等)等。     

Effect of different PVDF and additives on the properties of hollow fiber membranes contactors for CO2 separation

In the present work, different poly(vinil fluoride) (PVDF) were selected for preparing membranes, based on the fact that they are able to form polymer solutions with different viscosities. This characteristic can affect spinning, as well as, mass transfer between the polymer solution and precipitation bath; therefore, each PVDF solution can differently affect membrane formation. The effect of different additives in the polymer solutions was also investigated. Flat sheet and hollow fiber membranes were characterized by Scanning Electron Microscopy analysis, contact angle, gas permeation, porosity, and membrane gas–liquid contactor tests, aiming carbon dioxide removal. The hollow fibers prepared by the polymer which formed a less viscous solution (named PVDF-I) had a faster light transmittance decay, which started around 150 s before the more viscous solution (PVDF-II). Hollow fibers obtained using PVDF-I and propionic acid, in the polymer solution, presented the best gas–liquid contactor performance. CO₂ removal increased from 21 to 35.1%, for PVDF-II and PVDF-I, respectively, using aqueous diethanolamine solution, as absorbent liquid. In conclusion, even though PVDF-I and PVDF-II membranes were obtained by using the same spinning conditions and experimental methodology, the difference between the polymers properties certainly affected the final membrane morphology and transport properties.     

高比表面积金属丝网波纹填料的实验研究

在50 mm的微机化多功能精馏实验装置中,以乙醇-正丙醇为体系对4种高比表面积(分别为900,1100,1700,2500 m2/m3)的金属丝网波纹填料的流体力学和传质性能进行了研究。结果表明,2500Y型填料的阻力很高而传质效率较低。其他3种填料的传质效率随比表面积增大而提高,但900Y和1100Y型填料的综合性能较好。