Features of Multicomponent Mass Transfer in Gas Mixtures Containing Hydrocarbon Components

The features characterizing the transition from a diffusion process to the concentration gravitational convection in multicomponent gas mixtures containing hydrocarbon components are analyzed. It is demonstrated that this transition is possible due to the difference in interdiffusion coefficients of components, initial concentration of components, and the pressure of the experiment. A mathematical model for describing the transition from the diffusion process to the concentration gravitational convection in multicomponent gas mixtures is considered. The key feature indicating the transfer from the diffusion regime to the convective one is the curvature of an isoline of the heavy component of the gas mixture.     

Solution Method for Countercurrent Plug Flow Models of Multicomponent Gas Separation by Permeation

Abstract

A simple solution method was developed for the countercurrent ideal plug flow model of multicomponent gas separation by permeation that is commonly applied to hollow fiber membrane modules. The solution method is independent of the number of components in the feed gas. The result is an implicit function in a single variable defined as the stage cut. The function is readily solved by the method of damped successive substitution. The method was tested for three cases from the literature and found to be insensitive to the initial guess for stage cuts less than 60%.     

天然气净化膜及膜内气体传质机理研究

作者以碳氟高分子聚合物为膜材,通过辐射接枝技术,得到含氟羧酸膜（ＰＦＣＭ）,并分别用乙二胺（ＥＤＡ）、三乙醇胺（ＴＥＡ）、三乙烯二胺（ＴＥＤＡ）等三 活性载体,对ＰＦＣＭ进行改性,得到了酸性气体促进传质优先渗透酸性组份的特征。可用于 天然气净化。本文以ＣＨ４、ＣＯ２和Ｈ２Ｓ为对象,测定了上述几种膜内的吸收等温线数据和渗透动力学数据。分别考察了活性载体种类和改性度以及温度等参数对膜性能的影响。进而阐     

Analysis of Gas Centrifuge Cascade for Separation of Multicomponent Isotopes and Optimal Feed Position

Abstract

Analysis of the concentration distribution in a gas centrifuge cascade for separation of multicomponent isotope mixtures is different from that in a cascade for separation of two-component mixtures. This paper presents the governing equations for a multicomponent isotope separation cascade. Numerically predicted separation factors for the gas centrifuge cascade agree well with the experimental data. A theoretical optimal feed position is derived for a short square cascade for a two-component mixture in a close-separation case. The optimal feed position for a gas centrifuge cascade for separation of multicomponent mixture is discussed.     

含氟聚酰亚胺气体分离膜研究进展

介绍了一种新型气体分离膜材料-含氟聚酰亚胺,着重介绍了含氟聚酰亚胺的物理化学性质、气体选择透过性。对其发展历史及应用作了简要概述。通过与传统聚酰亚胺膜材料进行比较,指出了该膜材料的广阔发展前景,并对其今后发展方向进行了展望。     

多组元溶液分相条件的探讨

本文通过改型的UNIQUAC方程 ,利用NEWTON RAPHSON法计算了二元、三元及四元液液平衡数据。从中发现 ,当具有部分互溶性质组分的活度系数发生突变时 ,则该体系就会出现分层现象。为此 ,本文认为具有部分互溶组分活度系数的突变可做为多组元溶液分相的判据。     

Diffusion Characteristics in Ethyl Alcohol and Glucose Solutions Using Kedem-Katchalsky Equations

Formulas for calculating the viscosity and diffusion coefficients for two-component aqueous non-electrolyte solutions as a function of the solution concentration under isothermal conditions were derived. The dependence of diffusion coefficient, filtration coefficient, and dynamic viscosity coefficient for these solutions on the solution concentration was estimated and evaluated. Based on the obtained formulas, the results of diffusion coefficient, membrane filtration coefficient, and dynamic viscosity calculations for aqueous solutions of ethanol and glucose are presented and compared with literature data.     

气体膜分离技术及应用

简要介绍了有关气体膜分离的基本原理、材料及其在氢气分离回收、空气分离和酸性气处理中的应用,并对气体膜分离的发展前景提出了自己的见解。     

天然气长输管道火炬放空扩散规律研究

天然气的放空扩散非常危险,研究天然气长输管道火炬放空扩散的规律,可以为其安全放空提供指导依据。PHAST软件是公认的最权威最准确的后果分析软件,可以用于长输管道的天然气放空扩散计算。采用该软件建立天然气长输管道系统的亚临界流不点火放空的扩散模型,确定天然气在不点火放空过程中可能燃烧的危险区域。以某实际长输管道为例,计算两种工况下天然气扩散规律。结果显示,在放空过程中风速影响天然气的扩散。低风速时,天然气会向上扩散,在高风速时,天然气向水平方向扩散。天然气50%LFL云团水平距离随风速的增大而增加,云团高度随风速的增加而减小。     

A Gravitational Procedure to Measure the Diffusion Coefficient of Water in Porous Materials: A Case Study on Concrete

A new procedure is presented with which the diffusion coefficient of water in partially saturated porous materials can be measured. The first step in the procedure is the creation of a non-equilibrium situation inside a sample by placing it into a centrifuge. In the second step, the mass of the sample is measured by hanging it from two cables, each connected to a balance. The comparison of the time evolutions of the measured masses and the masses as predicted using Fick's second law gives the diffusion coefficient.     

Solution of the Diffusion Equations in a Gas Centrifuge for Separation of Multi component Mixtures

Abstract

The demand for stable isotopes in physical and chemical research and in medical diagnostics is growing, and the gas centrifuge process is able to provide large quantities of stable isotopes. A set of diffusion equations describing separation in a gas centrifuge for a multi component mixture is established. These equations involve general diffusion coefficients. Using the radial averaging method and the simplified diffusion transport vector for a multi component isotopic mixture, nonlinear partial differential equations are transformed to a set of nonlinear ordinary differential equations. An iteration method for the solution is presented. The relationship between the separation factor and the mass difference, γ _ij = γ ^Mj _o ^?Mi , is shown to be in agreement with both the computational and the experimental results with very high precision.     

Pu-I型吸附剂在少量CO、CO_2脱除和CO制取中的应用

介绍了Ｐｕ－Ｉ型吸附剂的开发和性能,对它在少量ＣＯ、ＣＯ２脱除和ＣＯ制取工艺中的应用也进行了分析。     

在线分析仪在空分中的应用

根据空分设备工艺特点,要获得合格的产品氧、氮、氩,必须设置一些在线分析仪器进行监控。介绍了空分中典型的分析点以及在线分析所需要配置的分析仪器。     

输气管道泄漏诊断技术综述

对近年来国内外输气管道泄漏检测与定位的主要方法进行了比较全面的总结与评述。从基于硬件的方法和基于软件的方法对输气管道故障诊断领域的研究成果进行了详细的介绍 ,重点介绍了基于现代控制理论和信号处理的方法。对各种方法 ,提出了九项指标 ,对其性能进行了全面的对比。最后指出了这一领域的研究热点和发展方向     

气体膜分离技术的进展及其应用

介绍了气体分离膜材料的种类;叙述了介绍了气体膜分离技术在分离空气制备富氧、富氮,水蒸气、有机蒸汽的分离和氢气回收等工业领域的应用.介绍了气体膜分离技术的研究进展,并提出了我国气体膜分离技术发展方向.     

分子模拟技术在气体膜分离研究中的应用

回顾了分子模拟技术在气体膜分离领域的应用，介绍了各种模拟方法的特点，阐述了具体的应用范围、存在的问题及发展趋势。表明分子模拟在定性分析气体与膜材料的亲和性、预测渗透系数和分离因子方面有一定价值，但离定量预测和分析还有一定距离，非平衡分子动力学是适用于气体膜分离研究的方法，其研究还处于初期阶段。     

酸性侵蚀性气体分离膜材料研究及应用进展

综述了CO2、H2S、SO2、Cl2及HCl等酸性侵蚀性气体分离膜材料的最新研究与应用进展,讨论了这类气体膜分离工艺对膜材料的要求,介绍了聚酰亚胺(PI)、聚二甲基硅氧烷(PDMS)、聚四氟乙烯(PTFE)、碳分子筛(CMS)等几种耐蚀分离膜材料的特征结构、特点、适用的气体分离类型及相应的分离机理。     

Highly Perm-Selective Micro-Porous Hydrotalcite-Silica Membrane for Improved Carbon Dioxide-Methane Separation

A notable improvement of carbon dioxide (CO₂) adsorption in meso- and micro-porous membranes was observed when hydrotalcite (HT) was incorporated in the membranes. For carbon dioxide in carbon dioxide-methane (CH₄) mixture, HT-silica membrane successfully overcame the upper permeability/selectivity limitation for glassy and polymeric membranes, despite the absence of a solution-diffusion mechanism that is typically present in the glassy and polymeric membranes. The performance of HT-silica membrane was observed to exceed that of micro-porous silica and high performance zeolitic imidazolate framework (ZIF) membranes. Incorporating unnecessarily high HT content in silica membrane, however, caused the membrane to lose its molecular sieving capacity and resulted in reduced selectivity of the gas.     

膜分离法油气回收的应用

基于回收栈台装车过程中油气挥发损耗量,通过某石化分公司炼油厂装车栈台敞口装车现状,简述油气挥发对环境污染、油品质量的影响及经济能耗损失。同时阐述膜分离法回收油气的工艺方法、应用效果、必要性和意义,并对油气回收发展前景、节能减排的优势,结合几种油气回收方式进行综合性能比选,得出膜分离法能够取得较好经济效果综合评价。