乙腈+[C4mim][Cl]、乙腈+[C4mim][BF4]、乙腈+[C6mim][Cl]的气液平衡测定与关联（英文）

Vapor pressures were measured for acetonitrile+1-butyl-3-methylimidazolium chloride ([C4mim][Cl]),+1-butyl-3-methylimidazolium tetrafluoroborate ([C4mim][BF4]) and+1-hexyl-3-methylimidazolium chloride ([C6mim][Cl]) at temperatures of 313 to 353 K by a quasi-static method. The experimental data for the binary sys-tems were correlated by the non-random two liquid (NRTL) equation with an average absolute relative deviation (AARD) of within 1.84%. The results indicate that the three ionic liquids (ILs) can result in a negative deviation from the Raoult's law for the binary solutions containing acetonitrile, and the affinity between ILs and acetonitrile mole-cules fol ows the order [C4mim][BF4]+acetonitrile N [C4mim][Cl]+acetonitrile N [C6mim][Cl]+acetonitrile.     

规整填料内气液两相流动与传质的计算传质学模型

Detailed investigation of flow behavior in structured packing distillation columns is of great importance in accurate prediction of process efficiency and development of more efficient and optimal equipment internals. In this study, a three-dimensional two-phase flow model based on VOF method for simulating the hydrodynamics and mass-transfer behavior in a typical representative unit of the structured packing is developed. In the proposed model, the model is used for the closure of turbulent mass transfer equation. By solving the proposed model, the velocity distribution, phase fraction profile and concentration field are obtained. Using these data, the total liquid holdup, the wetted area and the separation efficiency [height equivalent to a theoretical plate (HETP)] are estimated. For testing the model validation, the simulated HETPs are compared with our previous experimental data obtained in a 150 mm-diameter column containing Mellapak 350Y operating at the pressures of 0.6-1.8 MPa. The compari-son shows that they are in satisfactory agreement, with an average absolute deviation (AAD) of 25.4%.     

苯酚体系支撑液膜不稳定性研究

The instability mechanisms of the supported liquid membrane using Celgard 2500 membranes as support and tributyl phosphate dissolved in kerosene as carrier for phenol transport was studied by electrochemical impedance spectroscopy. Emulsion formation is demonstrated to be one of the main causes for the instability of supported liquid membrane in the present system. The emulsion-facilitated conditions, such as higher membrane liquid concentration, faster stirring speed, lower salt concentration and higher HLB value, would accelerate the degradation of supported liquid membrane. Other mechanisms including solubility and os-motic pressure work together to increase the membrane liquid loss.     

规整填料塔内两相流动的三维计算流体力学建模(英文)

Characterizing the complex two-phase hydrodynamics in structured packed columns requires a power- ful modeling tool. The traditional two-dimensional model exhibits limitations when one attempts to model the de- tailed two-phase flow inside the columns. The present paper presents a three-dimensional computational fluid dy- namics （CFD） model to simulate the two-phase flow in a representative unit of the column. The unit consists of an CFD calculations on column packed with Flexipak 1Y were implemented within the volume of fluid （VOF） mathe- matical framework. The CFD model was validated by comparing the calculated thickness of liquid film with the available experimental data. Special attention was given to quantitative analysis of the effects of gravity on the hy- drodynamics. Fluctuations in the liquid mass flow rate and the calculated pressure drop loss were found to be quali- tatively in agreement with the experimental observations.     

两液层体系传质引发的Marangoni效应的数值模拟

The Marangoni effect induced by mass transfer at the interface between two immiscible liquids displays important influence on laboratory and industrial operation of solvent extraction. A systematic numerical study of the two-dimensional Marangoni effect in a two liquid layer system was conducted. The linear relationship of the inter- facial tension versus the solute concentration was incorporated into a mathematical model accounting for liquid flow and mass transfer in both phases. The typical cases analyzed by Sternling ＆ Scriven （AIChE J., 1959） using the linear instability theory were simulated bv the finite difference method and good agreement between the theory and the numerical simulation was observed. The simulation suggests that the Marangoni convection needs certain time to develop sufficiently in strength and scale to enhance the interphase mass transfer, the Marangoni effect is dynamic and transient, and remains at some stabilized level as long as the mass transfer driving force is kept con- stant. When certain level of shear is imposed at the interface as in most cases of practical significance, the Maran- goni effect is suppressed slightly but progressively as the shear is increased gradually. The present two-dimensional simulation of the Marangoni effect provides some insight into the underlying mechanism and also the basis for further theoretical study of the three-dimensional Marangoni effect in the real world and in chemical engineering applications.     

二氧化硫和二氧化碳在离子液体支撑液膜中的渗透率和选择性

Permeabilities and selectivities of gases such as carbon dioxide (CO2), sulfur dioxide (SO2), nitrogen (N2) and methane (CH4) in six imidazolium-based ionic liquids ([emim][BF4], [bmim][BF4], [bmim][PF6], [hmim][BF4], [bmim][Tf2N] and [emim][CF3SO3]) supported on polyethersulfone microfiltration membranes are investigated in a single gas feed system using nitrogen as the environment and reference component at temperature from 25 to 45ºC and pressure of N2 from 100 to 400 kPa. It is found that SO2 has the highest permeability in the tested supported ionic liquid membranes, being an order of magnitude higher than that of CO2, and about 2 to 3 orders of magnitude larger than those of N2 and CH4. The observed selectivity of SO2 over the two ordinary gas components is also striking. It is shown experimentally that the dissolution and transport of gas components in the supported ionic liq-uid membranes, as well as the nature of ionic liquids play important roles in the gas permeation. A nonlinear in-crease of permeation rate with temperature and operation pressure is also observed for all sample gases. By considering the factors that influence the permeabilities and selectivities of CO2 and SO2, it is expected to develop an optimal supported ionic liquid membrane technology for the isolation of acidic gases in the near future.     

两相更新支撑液膜中金属二价镍的迁移行为研究(英文)

A novel disphase supplying supported liquid membrane(DSSLM),containing supplying feed phase and supplying stripping phase for transport behavior of Ni(II),have been studied.The supplying supported feed phase included feed solution and di(2-ethyhexyl) phosphoric acid(HDEHP) as the carrier in kerosene,and supplying stripping phase included HDEHP as the carrier in kerosene and HCl as the stripping agent.The effects of volume ratio of membrane solution to feed solution(O/F),pH,initial concentration of Ni(II) and ionic strength in the feed solution,volume ratio of membrane solution to stripping solution(O/S),concentration of H2SO4 solution,HDEHP concentration in the supplying stripping phase on transport of Ni(II),the advantages of DSSLM compared to the traditional supported liquid membrane(SLM),the system stability,the reuse of membrane solution and the reten-tion of membrane phase were studied.Experimental results indicated that the optimum transport of Ni(II) was ob-tained when H2SO4 concentration was 2.00 mol·L-1,HDEHP concentration was 0.120 mol·L-1,and O/S was 4:1 in the supplying stripping phase,O/F was 1︰10 and pH was 5.20 in the supplying feed phase.The ionic strength in supplying feed phase had no obvious effect on transport of Ni(II).When initial Ni(II) concentration was 2.00×10?4 mol/L,the transport percentage of Ni(II) was up to 93.1 % in 250 min.The kinetic equation was deduced in terms of the law of mass diffusion and the interface chemistry.     

毛细管泰勒流中气液相对流速及液膜厚度性质的实验研究

气液相对流速(W)、气泡周围的液膜厚度(δ)是认识毛细管内泰勒流性质的两个重要参数.以氢气、水为工作介质,考察了毛细管数(Ca),流体流动方向和毛细管直径对上述参数的影响.发现在本实验的毛细管数范围内,W与Ca近似地成线性关系,且W随着Ca的增大而增大.但是这种增大趋势受到流动方向和毛细管直径的显著影响.另一方面,根据气柱在毛细管中的运动模型计算了水平和垂直向上流动时的液膜厚度.发现液膜厚度随着W和Ca的增大而增大,其增大趋势也受到流动方向和毛细管直径的显著影响.     

液-液分散性质的研究概况

多相接触器,如反应器、萃取器,其性能无不与相分散的性质有关。分散相尺寸及其分布、相界面积,必然影响两相的流体力学性质、分散相滞存率(hold up)分布和停留时间分布。对于液-液系统而言,液滴的破碎及凝聚速率,对传质效果有重要影响。近年来,溶剂萃取塔的数学模型已有很大进     

毛细管Al_2O_3膜的制备及表征:薄膜形成机理对无缺陷膜制备的影响(英文)

Ceramic capillary membrane has received much attention due to its relatively high pack density and favorable mechanical strength.However,it is difficult to prepare capillary membrane on its thin support by a dip-coating method.In this study,alumina microfiltration membranes were prepared on the inner surface of alumina capillary support(outer diameter 4 mm,inner diameter 2.5 mm)by a dip-coating method.Scanning electron microscopy(SEM)observation,gas bubble pressure(GBP)method and membrane permeation test were carried out to evaluate membrane performance.Two major effects in preparation of crack-free membrane,capillary filtration and film-coating,upon the thin support were studied.The as-prepared crack-free membrane presents a narrow pore size distribution,a mean pore size of about 0.6μm and a high pure water flux of 86000 L·m -2 ·h -1 ·MPa.It is proved that the membrane thickness should be sufficiently large to overcome the defects of support surface,but it is only one of the prerequisites for the formation of crack-free membrane.Furthermore,it is demonstrated that the capillary filtration effect is greatly restricted for thin capillary support with the dip-coating method and the film-coating effect plays a crucial role in the formation of crack-free membrane.     

Effect of counter current gas phase on liquid film

Liquid film flow is very important in many industrial applications. However, there are few reports about its characteristics on structured packings. Therefore, in this paper, liquid film phenomena were investigated experimentally to exploit new approaches for intensifying the performance of the structured packings. All experiments were performed at room temperature. Water and air were the working fluids. The effect of counter current gas phase on the liquid film was taken into consideration. A high speed camera, a non-intrusive measurement technique, was used. It is shown that both liquid and gas phases have strong effects on film characteristics. In the present work, liquid film width increased by 57% because of increasing liquid flow rate, while it decreased by 25% resulting from the counter current gas phase.     

粘度对规整填料层泛点影响的研究

研究了粘度对规整填料层泛点的影响 ,对文献上规整填料层泛点的关联式进行了改进 ,利用新关联式可由空气 水物系的泛点实验数据计算其他物系的泛点空塔气速 ,新关联方法与实验数据吻合较好 ,计算准确性优于文献公式     

规整填料塔内液相返混的CFD模拟

通过对规整填料塔内部结构的分析,认为其内部存在三种基本结构单元：同一盘填料内的交叉单元、上下两盘填料旋转90度的衔接单元和填料与塔壁的衔接单元。使用RNG k—ε湍流模型对不同的结构单元进行三维CFD模拟计算,发现不同的结构单元具有不同的流动特性。同时．使用示踪激励响应技术,研究了不同结构单元的轴向返混情况。     

规整填料塔的壁流量计算

推导了板波纹填料塔的壁流量计算方法 ,并探讨填料层分段高度的选择。     

Liquid Holdup and Pressure Drop Determination in Structured Packing with CFD Simulations

It is discussed how Computational Fluid Dynamics (CFD) can be used for hydrodynamics calculations within structured packings. Three dimensional (3D) simulations, in which the influence of mesh size and turbulence models were tested, have been carried out for dry pressure drop determination. Two dimensional (2D) Volume of Fluid gas‐liquid flow simulations have been used for liquid holdup determination. Numerical results are compared to tomographic liquid holdup measurements. Then, a comparison with data from a gas treatment pilot plant shows that wet pressure drop can be predicted by combining these two types of information (dry pressure drop and liquid holdup).     

规整填料表面点传质的可视化研究

采用显色化学反应的流体可视化方法研究规整填料表面上的点传质效果。并且用高精度彩色扫描仪进行后处理,把颜色值转化为数字值。通过风洞的标定特性来建立数字值和点传质量之间的关系,进而得到填料表面的点传质系数。由填料表面点传质系数的三维分布图,可清晰地看到在每两片填料交叉形成的任一传质单元当中,存在3个传质高峰。     

加压下板波纹规整填料塔中液相混合行为

采用脉冲示踪法测量了在0．3MPa、0．5MPa和0．6MPa压力下以及在一系列液速和气速下250Y型孔板波纹规整填料内液相的混合行为。应用时域最小二乘法由实验数据得到了液相的轴向返混系数和轴向有效流速等参数,并以y=aReL^e10^cReG10^dp的形式对轴向Peclet准数进行了关联。本研究补充了目前缺乏的加压操作下规整填料液相混合行为的数据。     

加压下规整填料塔内气液两相轴向返混实验研究

An experimental study of the extent of axial backmixing in both gas and liquid phases was conducted in a 150 mm ID column packed with Mellapak 250Y corrugated structured packing. The column was operated at pressures ranging from 0.3 MPa to 2.0MPa with nitrogen and water flowing countercurrently through the packing. The amount of axial backmixing was experimentally evaluated by the pulse response techniques using hydrogen in gas phase and an aqueous solution of NaCl in liquid phase as inert tracers. The response of the tracer was monitored by means of thermal conductivity in the gas phase and electrical conductance in the liquid phase. The experimentally determined residence time distribution (RTD) curves were interpreted in terms of the diffusion-type modei. The results indicated that the axial backmixing in the gas increased notably with gas flowrate and slightly with operating pressure and liquid flowrate. The liquid-phase axial backmixing was an increasing function of both gas and liquid flowrates an     

规整填料塔内流体流动研究进展及展望

阐述了规整填料塔内流体流动研究的进展 ,在理论研究方面 ,用五种模型对国内外学者的研究进行了分类和细致地描述 ,并对各模型进行了评述 ;在实验研究方面 ,对各种实验方案进行了归纳总结 ,论述了各自的优缺点。对该领域的研究进行了展望 ,认为用计算流体力学模型来描述规整填料塔内流体的流动将是今后的发展方向。