促进传递液膜分离丙烯(Ⅱ)数学模型

基于载体Ag~+与丙烯发生瞬时可逆反应的事实,根据传质理论,推出了简化的促进传递液膜分离丙烯的传质模型,并通过实验数据回归,得出了两种不同支撑体时的模型参数,所得结果验证了模型的正确性．     

气体传递膜

膜接触器是被水处理工业所接受的最新技术,它补充了以膜为基础的技术和反渗透、微滤、超滤和连续去离子模件性。本文评述膜接触器的进展和未来前景。     

促进传递液膜分离丙烯(Ⅰ)工艺条件

用含有AgNO3载体的支撑液膜对丙烯进行促进传质分离,研究了不同工艺条件、支撑体材料等因素对丙烯纯度、渗透速率、单程收率及选择性因子的影响．在最佳条件下,丙烯的纯度达99.3％～99.7％,单程收率5.6％,选择性因子＞700．给出了液膜稳定性处理方法．实践证明,支撑液膜促进传递过程明显优于被动的溶解-扩散过程．     

液膜脱酚的综合传质模型

本文研究了液膜传质过程中的各种复合因素,提出描述该过程的综合传质模型.考虑到液滴内外传质阻力及膜破裂等因素的影响,本模型将著名的“渐近前沿模型”作适当调整.模型参数k_o和B_m由Powell优化方法最优拟合实验值决定.实验结果证实本文所建议的传质机理模型比较符合实际,并具有适用的弹性.     

液膜法提取钼的研究——传质模型的改进

本文提出了一种改进的关于液膜传质的数学模型.该模型不仅考虑了非稳态下膜相扩散阻力,而且还考虑了外相边界层的扩散阻力及膜破裂.采用扰动法求得了非线性方程组的近似解,并用间歇式液膜法提取钼实验进行验证,结果表明,外水相浓度较大者,膜相扩散阻力占主导地位,此时可不考虑外相边界层的扩散阻力,反之则应考虑.而膜破裂因素,特别是在反应后期影响较大.模型计算与实验结果取得了较好的一致性.     

溶剂在高分子膜中的传递模型

用Voigt蠕变模型和Flory-Huggins混合模型分别计算溶剂在高分子膜中吸收和解吸过程高分子的蠕变及与溶剂混合的吉氏函数变化,结合质量守恒建立了一个小分子在玻璃态聚合物中吸收和解吸的传递模型,模拟计算结果和对实际系统的吸收和解吸曲线的关联和预测结果表明,模型能很好地描述实验中常遇到的S形吸收曲线,并能根据吸收曲线的实验信息预测相应的解吸曲线。与Crank模型比较,此模型具有参数少而灵活的优点。     

质子交换膜燃料电池水传递模型

提出了用于研究质子交换膜燃料电池膜中水分布、水传递量分布、电流密度分布等的二维数学模型;系统地考察了电池温度、阴阳极压力差、增湿程度、质子膜厚度等条件对水的传递和膜中水分布的影响.计算结果表明:①阳极增湿能够提高气体进口段膜阳极侧水的含量;②使用越薄的质子膜,越能提高膜中水的含量;③阳极增湿程度越大,由阳极向阴极迁移的水量越多.     

溶剂在高分子膜中传递现象研究的进展

溶剂在高分子膜中吸收和解吸的传递机理非常复杂,对其传递过程的研究有助于膜分离过程的开发、膜材料的选择。本文对溶剂在高分子膜中传递现象研究的进展作简要介绍。     

聚丙烯支撑液膜提取柠檬酸的传质条件

用聚丙烯支撑液膜从柠檬酸溶液中提取柠檬酸,通过正交实验考察和分析料液相浓度、反萃取相浓度、搅拌速率、温度等因素的影响,得到最佳传质条件：料液相浓度为0．4mol／L、反萃取相浓度0．1mol／L、搅拌强度300r／min、传质温度25℃。同时对该膜体系进行连续提取实验,结果表明最佳传质条件下膜体系稳定性较好,膜通量下降后可通过重新浸泡得以恢复,继续使用。     

液膜法提取废水中柠檬酸动力学传质模型的研究

本研究在探讨液膜法提取废水中柠檬酸机理的基础上,进行合理假设,建立了恒界面状况下的简化非稳态平板动力学传质模型,并利用恒界面条件下的实验数据对拟稳态平板动力学传质模型进行了拟合,取得较为满意的拟合效果。     

MASS TRANSFER OF SULFURIC ACID BY TRIOCTYLAMINE THROUGH A SUPPORTED LIQUID MEMBRANE

The extraction of sulfuric acid in a supported-liquid membrane (SLM) process, and the kinetics of extraction and stripping of sulfuric acid in a cell of constant interfacial area by trioctylamine (TOA)/kerosene solvent were investigated. The kinetics of extraction and stripping were determined by examining the effects of the operating variables. The extraction rate is a function of the activity of sulfuric acid and the concentration of TOA; the stripping rate is a function of the concentration of trioctylamine sulfate salts in the organic solution. A generalized transport model, which included the film diffusion of sulfuric acid in the aqueous phase, the membrane diffusion within the SLM, and the interfacial chemical reaction, was built. The permeability of sulfuric acid through the SLM using TOA as a mobile carrier was determined. The rate-determining step of the extraction of sulfuric acid through a SLM was analyzed using the data obtained from the experiments of extraction kinetics and the mass transfer in the aqueous phase. Diffusion within the membrane dominates the process of extraction process of sulfuric acid by TOA through a SLM.     

XD型膜包络体控制释放过程传质模型

对由内包络体和大孔型控制释放膜构成的ＸＤ型膜包络体的释放过程进行了分析，推导了恒速段的传质模型。对控释曲线恒速段进行数学模拟。提出了膜结构参数ω，并对其数值确定方法进行了研究。     

温度对气态膜过程传质性能影响

本文通过对文献数据的整理计算,说明对于易挥发体系(溶解度系数Hf<<1),温度主要影响组分在液相的扩散系数对气态膜过程的总传质系数产生影响;对于具有中等溶解度的体系(Hf≈1),传质同时受液相阻力和膜阻控制;对于难挥发体系(Hf>>1),温度主要通过改变气液平衡关系对传质系数产生影响。     

A MODEL FOR MASS TRANSFER IN OSCILLATING-CIRCULATING LIQUID DROPS†

Velocity vector computations based upon flow-visualization techniques have enabled the development of a detailed model for flow patterns in a droplet-continuum system typical of liquid-liquid solvent extraction. Experiments show that the streamlines for flow in and around circulating droplets which are forced into regular oscillation by a pulsing electric field can be modeled as the vectorial sum of low-Reynolds-number internal circulation (Hadamard flow) and an oscillatory streaming caused by the prolate-to-oblate ellipsoidal shape changes of the droplet (Dirichlet flow). The convective-diffusion equations have been derived and numerically solved for mass transfer from both circulating droplets (Hadamard flow) and oscillating-circulating droplets (mixed Hadamard-Dirichlet flow). The resulting rate of mass transfer from an oscillating-circulating droplet is significantly greater than that from the equivalent circulating droplet. The rate of mass transfer is dependent upon oscillation frequency and amplitude, droplet Peclet number, the interphase distribution coefficient of the transferring species, and physical properties of each fluid phase.     

几种新型的支撑液膜组件的结构型式

本文介绍四种新型支撑液膜组件的型式和特点。它们分别是：中空纤维夹芯型膜组件、管式－中空纤维混合式膜组件，板式夹芯型膜组件和框式隔板夹芯型膜组件。     

MASS TRANSFER INTO A FREE LIQUID SURFACE EFFECTED BY SUBMERGED JETS

A theoretical and experimental analysis of mass transfer into a turbulent free liquid surface effected by submerged jets has been presented. Theoretical considerations concentrated on hydrodynamic characteristics of the system which enabled us to derive the radial velocity distribution in the surface jet flow. Some conclusions have been drawn from the two-parameter models of turbulence. The results of experimental measurements of the average mass transfer coefficients have been interpreted in terms of our own model of mass transfer accounting for eddy diffusivity. The model parameters were correlated with the basic hydrodynamic parameters of the system. Radial distributions of the local values of the mass transfer coefficients were estimated. The applicability of other models of mass transfer has also been verified. It has been shown that the model presented here is the most general and applicable for interpretation of the experimental data obtained when studying the system under consideration