泡沫精馏塔内泡沫液的传质模型

本文对泡沫精馏塔内泡沫的传质问题进行了分析，提出传质微分方程，得到了解析解，并用实验验证了解的正确性。     

支撑液膜萃取乳酸传质模型

本文对使用支撑液膜(Supported Liquid Membrane)从水溶液中革取乳酸(HL)的过程进行了理论分析,经过适当的简化,推导出支撑液膜革取乳酸的传质模型。对模型进行了实验验证,测得了膜的弯曲因子及过程的促进因子,模型计算值与实验值相吻合,同时得出膜内载体三烷基氧磷(TRPO)与乳酸形成的萃合物分子式为HL·TRPO。     

Computational Simulation of Mass Transfer in Molecular Separation Using Microporous Polymeric Membranes

Computational simulation was conducted to predict mass‐transfer phenomenon in the molecular separation of solute using microporous membrane contactors. Both diffusional and convectional mass‐transfer mechanisms were considered. The membrane system was a hollow‐fiber contactor in which an aqueous phase containing an organic compound was contacted with an organic phase for extractive separation of the solute. Benzoic acid was used as the solute. The main focus was on understanding the mass transfer of solute in the process. The concentration equation for the solute was solved numerically using a computational fluid dynamics approach. It was found that the model can predict the solute transport from the aqueous phase to the organic phase and can be used as a predictive model for process understanding.     

反应诱导相分离热解法制备交联互通状多孔炭单体

以酚醛树脂和乙二醇混合物经过反应诱导相分离热解后形成的多孔炭单体制备复杂形状SiC陶瓷。通过用场发射扫描电子显微镜和压汞仪对多孔炭进行表征,分别研究了乙二醇含量、催化剂含量以及预固化温度对多孔炭的孔形貌、尺寸及分布的影响。结果表明：乙二醇含量可以影响多孔炭单体的形成,以及孔的形貌、大小和分布;催化剂含量和预固化温度对多孔炭的影响不显著。     

鼓泡塔中非牛顿流体体系的传质研究

本文在直径0.10 m、高1.05 m的鼓泡塔中,以羧甲基纤维素钠作为模拟介质,采用单孔喷嘴布气、孔径d_o=0.01 m,测定了该类反应器的比相界面积和容积传质系数,提出了比相界面积和传质系数的关联式。     

乳状液膜分离Zn^2＋的界面传质阻力及传质模型

用Ｌｗｅｉｓ恒界面传质池对乳状液膜分离Ｚｎ＾２＋的传质阻力进行实验研究，结果表明由于表面活性剂单分子层的形成，使界面传质阻力占整个传质阻力的８５％。在此基础上所建立的既考虑界面传质阻力又考虑膜破碎的液膜传质模型能使用理论计算值与实验测定值符合较好。     

传质分离过程理论塔板数的简捷计算

本文在图解法的基础上,通过分析理论塔板与操作线、平衡线之间的关系,建立了适用于气体吸收、液体精馏及液液萃取过程的传质单元数与理论板数间的对应关系,并利用工业低含量物质传质过程,对此关系式进行验证。与实际比较,结果基本一致,且计算过程简单、快捷,可帮助学生加深对传质过程的认识。     

吸附式制冷中吸附剂传热传质的强化

对吸附式制冷系统中吸附剂的两种关键性能－有效吸附量及导热系数进行了实验及理论研究。测量了几种吸附剂的上述性能并进行了数据拟合,分析了吸附剂吸附性能及导热系数对吸附制冷系统效率的影响,提出了以吸附制冷最佳经济效率为目标函数的吸附剂性能强化手段,并进行了一些实验研究,取得了较好的效果。     

H2O2吸收SO2的降膜传质系数模型的建立

为中小型燃煤锅炉烟气脱硫提出一种以列管式并流降膜塔为脱硫反应器,H2O2溶液为脱硫剂的简便高效、无二次污染的脱硫技术.建立了气、液相传质系数模型,通过实验数据回归了降膜管传质关联式.对气、液相传质系数模型进行验证,结果显示,得出的计算结果与实验数据基本相符,这表明建立脱硫模型对基本设计参数的确定具有一定的指导意义.     

Computational Fluid Dynamics Simulation of Mass Transfer in the Separation of Fermentation Products Using Nanoporous Membranes

The simulation of fermentation product separation using nanoporous membranes is presented. The aim of the simulation was to predict the performance of an extraction process to remove compounds from aqueous solutions. The simulation was conducted using computational fluid dynamics techniques for the solution of governing equations. The system studied was a membrane‐based extractor of acetone from aqueous solutions using near‐critical CO₂ as solvent. The predicted extraction percentages obtained by the simulations were compared to experimental values reported in the literature and showed very good agreement. The simulation can predict the concentration profile of acetone in the membrane and also predicts the formation of a concentration boundary layer.     

Comparison of the Generalized Species Transfer Model with a Two-Field Approach for Interfacial Mass Transfer

Two different approaches can be applied to calculate the mass transfer in a two-phase system using computational fluid dynamics and the volume-of-fluid method, single-field and two-field approaches. The used method affects the stability of the calculation as well as the accuracy of the result. Two volume-of-fluid-based approaches, namely, the generalized continuous species transfer model, a single-field approach, and a two-field approach are compared. The models are implemented in the OpenFOAM® framework and validated in a 1D test case. Although both approaches show great agreement with the analytical solution for large time steps, numerical instabilities of the two-field model are revealed with a reduced time step size, which leads to false results.     

A Simple Approach to Measuring the Gas Phase Heat and Mass Transfer Coefficients in a Bubble Column

A simple experimental approach was developed to measure the gas phase volumetric heat and mass transfer coefficients in a bubble column and a slurry bubble column employing a single gas nozzle. The experimental technique was based on a transfer model that simulates humidification and direct contact evaporation models in the case of a gas bubble rising in a liquid of uniform temperature. The temperature and relative humidity of the inlet and outlet gas in the column are the only measurements required in this technique. Experiments were carried out in a 0.15 m inner diameter column using water as the liquid phase, air as the gas phase, and cation resins of 0.1 mm diameter and a specific gravity of 1.2, as the solid phase. The results showed that, when using solid concentrations in the range of 7–10 wt %, both the volumetric gas‐phase heat and mass transfer coefficients increased with an increase in the gas superficial velocity and were further enhanced by increasing the solid load after a certain minimum superficial velocity had been reached in the column (0.044 m/s in the system used). Increasing the solid load beyond 10 wt %, did not contribute to a further increase in these coefficients. Furthermore, the gas holdup in the column increased with the superficial gas velocity and was further enhanced when the solid‐phase load was in the range of 7–10 wt %. These observations agree well with previously reported findings by other investigators.     

运用手性固定相研究外消旋布洛芬的光学分离

Ibprofen is widely used as a non-steroidal anti-inflammatory drug and poduced as racemic mixture.Its pharmacological activity resides only is S-( )-enantiomer,and R-(-)-enantiomer is not only inactive but also has many side effects.Thus it is necessary to separate Renantiomer from racemic ibuprofen.We studied optical separation of racemic Ibuprofen with chiral high performance liquid chromatography(HPLC).,Out of three different chiral stationary phases,which were selected on the basis of structure and availability,two were found to be effective.There was optimum eluent composition for each stationary phase for good resolution in optical separation.Resolution decreased with increase of eluent flow rate,but effect of injection volume on resolution was insignificant at high eluent flow rate.     

旋流塔板传质模型研究

根据旋流塔板上的气液运动规律，建立气相二维定数混合池传质模型，并用ＣＯ_２－ａｉｒ／Ｈ_２Ｏ物系的传质试验结果进行验证，结果表明，模型计算值和实验值相当吻合。     

Mass and Heat Transfer in a Continuous Plate Dryer

Abstract

A mathematical model for the mass-heat transfer in a continuous plate dryer has been developed. Along with a new mass transfer model, the formulas for several important parameters, such as height, volume of each granular heap and retention time, are provided. According to the penetration model of particle heat transfer, the average drying rate ([mdot]) is predicted together with the mean bulk temperature (T _out) and moisture content (X _out) by a straightforward stepwise calculation procedure. The only empirical parameter N _mix can be predicted by the method, provided that experimental data with various initial moisture contents (X _in) are given. According to the model, the optimization of a plate dryer should aim at the maximizing of the effective covering ratio (μ) and the total area-averaged heat transfer coefficient (α). The model and equations were applied in an experimental plant. In the result, the theoretical predictions are shown to be in satisfactory agreement with experimental data.     

Correlation of Mass Transfer Coefficients in Supercritical CO2 Separation Process

Weighted least squares and error-in-variable statistical methods were used to minimize variations in the experimental data set obtained from literature, and were used to validate Models I and II, S h′ = 0.0015(R e ^1/2 S c ^1/3)^2.58 and S h′ = 0.00084(R e ^0.4299 S c ^0.8783), respectively. Published data were used for the empirical estimation of mass transfer coefficients in separation processes in fixed bed systems using supercritical carbon dioxide extraction with low molecular diffusion. Model I gained accuracy when the Schmidt Number Sc is high (> 70) and the molecular diffusion is weak. The exponential ratio of the Re and Sc of Model II differed from the common ratio of 3:2; however, the exponents of the Sc are unique for both Models I and II.     

Comparison of Hydrodynamics and Mass Transfer in Airlift and Bubble Column Reactors Using CFD

Computational Fluid Dynamics (CFD) is used to compare the hydrodynamics and mass transfer of an internal airlift reactor with that of a bubble column reactor, operating with an air/water system in the homogeneous bubble flow regime. The liquid circulation velocities are significantly higher in the airlift configuration than in bubble columns, leading to significantly lower gas holdups. Within the riser of the airlift, the gas and liquid phases are virtually in plug flow, whereas in bubble columns the gas and liquid phases follow parabolic velocity distributions. When compared at the same superficial gas velocity, the volumetric mass transfer coefficient, k_La, for an airlift is significantly lower than that for a bubble column. However, when the results are compared at the same values of gas holdup, the values of k_La are practically identical.     

Liquid Phase CO2-Analytics for Standardized Mass Transfer Characterization in Packed Columns

Mass transfer parameters are necessary for the design of absorption and desorption processes in packed columns. To determine the effective interfacial area and liquid side mass transfer parameters, CO₂ absorption and desorption are frequently used. Reliable analytics for concentration determination are essential to obtain correct results. In this work two methods of CO₂ liquid phase analysis are compared: first, the back titration of unreacted NaOH after prior precipitation of the bound CO₂; secondly, the inorganic carbon analysis with a commercial inorganic carbon analyzer.     

土壤气相抽提过程非水相液体与气相的传质动力学研究

The mass transfer between non-aqueous phase liquid(NAPL) phase and soil gas phase in soil vapor extraction(SVE) process has been investigated by one-dimensional venting experiments. During quasi-steady volatilization of three single-component NAPLs in a sandy soil, constant initial lumped mass transfer coefficient (λgN,0) canbe obtained if the relative saturation (ξ) between NAPL phase and gas phase is higher than a critical value (ξc), andthe lumped mass transfer coefficient decreases with ξ when ξ＜ξc. It is also shown that the lumped mass transfercoefficient can be increased by blending porous micro- particles into the sandy soil because of the increasing of theinterfacial area.     

Kinetic Mass Transfer Between Non-aqueous Phase Liquid and Gas During Soil Vapor Extraction

The mass transfer between non-aqueous phase liquid(NAPL) phase and soil gas phase in soil vapor ex-traction(SVE) process has been investigated by one-dimensional venting experiments. During quasi-steady volatilization of three single-component NAPLs in a sandy soil, constant initial lumped mass transfer coefficient (λgN,o) can be obtained if the relative saturation (ξ) between NAPL phase and gas phase is higher than a critical value (ξc), and the lumped mass transfer coefficient decreases with ξ when ξ<ξc. It is also shown that the lumped mass transfer coefficient can be increased by blending porous micro-particles into the sandy soil because of the increasing of the interfacial area.