Multicomponent Vapor Research Articles

Mixture analysis of organic solvents using nonselective and nonlinear Taguchi gas sensors with artificial neural networks

This paper presents a protoytpe multicomponent gas and vapor analysis system consisting of eight nonselective and nonlinear Taguchi gas sensors, a temperature sensor, and multivariate calibration algorithms such as modified artificial neural netowrks. The application of this system to analyzing two- and three-component mixtures of benzene, toluene, acetone and trichloroethylene is demonstrated.

Separation of small molecules using novel rolltruded membranes. I. Apparatus and preliminary results

AbstractA novel membrane production technique, rolltrusion, has been developed for the preparation of permselective polymeric membranes for both gas and vapor separations and pervaporation applications. Pinhole‐free thin films with a regulated three‐dimensional morphology comprising crystalline and amorphous regions have been produced with improved mechanical properties in three dimensions. Because rolltrusion is a solid‐state processing technique, it is not restricted by solubility constraints inherent in the common solvent‐based thinfilm production techniques. Consequently it can be extended to include commercially available engineering plastics that have not been used as membranes previously because of their limited solvent solubility. These polymers are interesting because of their applicability to temperatures in excess of 200 to 300°C in harsh chemical environments, compared with the ca. 150°C ceiling usually encountered in the most rugged of solvent‐cast polymers. In the first part of this series we detail an automated experimental permeation apparatus that permits testing of both single‐component and multicomponent gases and vapors over a temperature range of −73 to 273°C. Currently, modifications to the permeation cell are underway to permit pervaporation studies in the apparatus. To illustrate the operation of the apparatus, and to some degree the effect of rolltrusion processing, experimental permeability, diffusivity, solubility, and actual gas separation factors (via gas chromatography) are detailed for several light gases in rolltruded isotactic poly(propylene) (iPP) and in the thermally and chemically resistant thermoplastic, poly(ether ether ketone) (PEEK). Permeation temperatures to at least 225°C have been studied using PEEK, representing the first published experimental permeability and gas‐separation results for such engineering polymers at temperatures above 200 °C. © 1992 John Wiley & Sons, Inc.

Difference in Transport Behavior between Aliphatic and Aromatic Petroleum Vapors in Unsaturated Soil

Unsteady state multicomponent vapor transport experiments in large (10.5 cm × 100 cm) columns packed with dry and wet soil and dry sand were used to evaluate the difference in transport behavior between aliphatic and aromatic petroleum vapors. The experimental data were analyzed using a modified diffusion equation accounting for vapor sorption and vapor partitioning into the soil moisture. Excellent agreement between the diffusion model and the experimental data was observed for all vapors studied in dry sand and dry soil and for aliphatic vapors in wet soil. However, a poor agreement was observed between the model and the aromatic vapors in wet soil. This was attributed to mass transfer limitation and violation of the local equilibrium assumption used to describe aromatic vapor partitioning into the soil moisture. Significant reduction in retardation factors for all vapors was observed in wet soil due to sorption competition by water molecules, but aromatic retardation factors were higher than the aliphatic ones, because of their high solubility and partitioning into the soil moisture.

Application of the VdW-711 equation of state to polar mixtures: correlation of binary and prediction of multicomponent vapour—liquid equilibria

The VdW-711 equation of state for polar compounds of Androulakis et al. (1989) is combined with the UNIQUAC model for the excess Gibbs free energy to establish the mixing rule in the attractive term of the equation of state. The obtained model, applicable thus to both vapour and liquid phases, eliminates the uncertainty in estimating the vapour phase non-ideality, a serious problem in using the gamma—phi approach, especially at higher pressures. Application of the model: (i) the correlation of binary vapour—liquid equilibria (VLE) data of polar systems and (ii) the prediction of multicomponent VLE behaviour from binary data, gives very good results, comparable to those with the gamma—phi approach, in both cases. In addition, successful prediction of saturated liquid volumes is obtained. Prediction of liquid volumes of mixing is also discussed.

Recent Progress of Japanese Research on Condensation Heat Transfer

A state-of-the-art review is presented on the research activities in Japan on condensation heat transfer during these nine years. The papers published on the Trans. JSME (Series B for thermal and fluids engineering) from 1980 until 1988 are chosen as the main target of the review, since it is considered that the majority of principal achievements in condensation research in Japan are contained in these volumes. The papers printed elsewhere on other publications or prior to 1980 are referred to only whenever it is needed. The author classifies the subjects into five items. They are (1) Film condensation of single-component vapor, (2) Film condensation of multi-component vapor, (3) Enhancement of condensation heat transfer, (4) Dropwise condensation, and (5) Direct contact condensation and other forms of condensation. However, the author’s effort is focussed mostly on the item (3) on the techniques of enhancement of condensation heat transfer. Dropwise condensation is another subject that is discussed in some detail. Only the outlines are presented for the remaining items. In the concluding remarks of this article the author’s personal comments on the future trends of the condensation research is presented.

Designing heat-exchanger networks for energy savings in chemical plants

The pinch-design method is applied to the evaluation of heat-exchanger networks for an existing monomer plant. The problem resulting from partially condensed multicomponent vapor streams possessing variable CP ( m ̇ C p ) values is solved by applying a novel technique. The rigorous design obtained is further revised by the consideration of plant constraints.

Condensation heat transfer - Recent progress of Japanese research.

A state-of-the art review is presented on the research activities in Japan on condensation heat transfer during these nine years. On writing this article the author has decided to choose those papers which have been published on the Trans. JSME from 1980 until 1988 as the main target of the review. The papers printed elsewhere on the other publications or prior to 1980 are referred to only whenever it is needed. The author classifies the subjects into five items. They are ; (1) Film condensation of single-component vapor, (2) Film condensation of multi-component vapor, (3) Enhancement of condensation heat transfer, (4) Dropwise condensation, and (5) Direct contact condensation and other forms of condensation. However, the author's effort is focussed mostly on the item (3) on the techniques of enhancement of condensation heat transfer. Dropwise condensation is another item that is discussed in some detail. Only the outlines are presented for the remaining items. Also it should be noted that the papers referred to in this article do not cover all the publications on condensation heat transfer even for those published after 1980 on the Trans. JSME, though more than 100 references are cited.

Prediction of mixed gas solubility at high pressure

A variety of theories (UNIQUAC, NRTL, Wilson) are available for predicting multi-component vapor—liquid equilibria from activity coefficients measured for the constituent binaries. These activity coefficients are based on deviations from ideal mixing of pure liquids. However, if some of the components are supercritical gases, they do not exist as pure liquids and defining the standard state of a hypothetical liquid is problematic. We propose instead a procedure called ISAC for isoactive solvent in which the constituent gas-liquid binaries are the standard state. The mixing process is based on a ψ potential, a Legendre transformation of the Gibbs free energy for which the activity of the solvent is an independent variable. In this way, solubilities of mixed gases in a liquid solvent can be predicted from experimental data on single-gas solubifities. Predictions are compared to four ternary systems consisting of two gases dissolved in a liquid solvent at pressures from 20 to 250 atm, and the agreement is excellent.

Thermochemical modeling of interfacial reactions and selective deposition at growth from the vapor

Advances in various computational techniques for chemical equilibria now enable complex multicomponent chemical vapor deposition systems to be analyzed. The results obtained from the thermodynamical calculations can be used to construct ‘‘road maps’’ indicating how changes in the experimental parameters can affect deposition conditions. In this paper, thermochemical modeling and its use are discussed for two major areas: (i) Interfacial reactions at the initial stages of growth. These reactions influence adhesion, autodoping, grain size, and topography of the interface. (ii) Selective deposition processes based on differences in chemical reactivity between different substrate areas. Parameters for prediction of selectivity and for identification of selectivity modifiers are introduced.

Estimation of breakthrough time on activated carbon fixed bed adsorbers for multicomponent organic solvent vapors.

The estimation of breakthrough time for multicomponent organic solvent vapors on activated carbon fixed beds is significantly complicated and difficult. This paper describes a simple estimation method of breakthrough time for the first component (foremost breakthrough component) in two- or three-component organic solvent vapors on an activated carbon fixed bed. The breakthrough time for the first component was expressed by the harmonic mean value of the breakthrough times in each pure component. Estimated breakthrough times were compared with the experimental ones.

Effects of a small amount of noncondensable gas on film condensation of multicomponent mixtures

The effects of a small amount of noncondensable gas on film condensation of multicomponent vapor mixtures are analytically studied. The governing equations of mass transfer and phase equilibrium of multicomponent species at the liquid-vapor interface are solved with perturbation due to the addition of a small amount of noncondensable gas to the main vapor mixture to obtain its behavior in the process of film condensation. Generally, the overall condensation rate is not always to be decreased with introducing the noncondensable gas into the multicomponent mixture. For small temperature difference across the condensate layer, the condensation rate decreases proportionally to the mole fraction of noncondensable gas accumulated at the interface. The results are applied for two binary systems of condensable and condensable species as well as condensable and noncondensable species with a numerical example.

A generator for producing multicomponent organic solvent vapor in inhalation chambers

A vapor generator for multicomponent organic solvents was developed and its performance was investigated experimentally. The vapors were generated from the surface of a sintered sphere of glass beads containing the organic solvents. The solvents were automatically supplied from the solvent reservoir to the sphere by suction pressure caused by the evaporation of the solvents and the generated vapors kept at constant high concentration over a long period. The vapor concentration increased with the decreasing flow rate and the increasing gas temperature. The concentration ratio of the generated vapor was found to be equivalent to the mixing ratio of solvents in the reservoir, so this device can generate multicomponent organic solvent vapors at any concentration ratio. The vapor generator is simple to construct and is recognized to be useful for investigation of inhalation toxicities of multicomponent organic solvent vapors.

Adsorption Characteristics of Multicomponent Vapors on the Fixed Bed of Activated Carbons

Adsorption Characteristics of Multicomponent Vapors on the Fixed Bed of Activated Carbons

On the condensation of multicomponent vapours in the presence of inert gases

The paper deals with the analysis of simultaneous heat and mass transfer at the condensation of multicomponent vapour in the presence of inert components. The results of numerical calculations of condensers, based on the solution of the individual versions of process model, resulting from the different description of multicomponent mass transfer, have been compared with the experimental data available. It has been found that best agreement was obtained in the case of variant based on Krishna-Standart method, whereas the shortest computing time was needed for the variant based on Burghardt-Krupiczka method yielding the results differing not significantly from the most accurate ones.

Experimental and theoretical studies of the laws governing condensate deposition from combustion gases

A description is presented of the results of a research program directed at an improved understanding of condensate deposition rate phenomena in combustion systems. The conducted experiments make use of real-time optical laser reflectance-interference-polarization techniques in flame environments. The obtained new data and the results of previous gravimetric experiments are employed as a basis for the development of a comprehensive convective diffusion deposition theory, taking into account the assumption of a multicomponent vapor or multisize class particles 'source-free' boundary layer. The theory makes it possible to provide self-consistent salt/ash/soot deposition rate predictions over a wide variety of environmental conditions.

Computer calculations for multi‐component vapour–liquid and liquid–liquid equilibria, J. M. Prausnitz, T. F. Anderson, E. A. Grens, C. A. Eckert, R. Hsieh and J. P. O'Connell, Prentice‐Hall Inc., Englewood Cliffs, N. J., 1980. No. of pages: 353

International Journal for Numerical Methods in EngineeringVolume 15, Issue 11 p. 1729-1729 Book ReviewFree Access Computer calculations for multi-component vapour–liquid and liquid–liquid equilibria, J. M. Prausnitz, T. F. Anderson, E. A. Grens, C. A. Eckert, R. Hsieh and J. P. O'Connell, Prentice-Hall Inc., Englewood Cliffs, N. J., 1980. No. of pages: 353 A. V. Jones, A. V. Jones CETIS, C.C.R., Ispra (Varese), ItalySearch for more papers by this author A. V. Jones, A. V. Jones CETIS, C.C.R., Ispra (Varese), ItalySearch for more papers by this author First published: November 1980 https://doi.org/10.1002/nme.1620151114AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Volume15, Issue11November 1980Pages 1729-1729 RelatedInformation

The simulation of steady state behaviour of the dephlegmation of multi-component mixed vapours

The partial condensation or dephlegmation process is generally used for the production of liquid reflux and vaporous disdilate with an additional fractionation in wetted wall column heat exchangers. All known calculations of the performance of vapour condensers are based on a film model, originally derived for binary vapour systems by Ackermann and by Colburn and Drew and generalized for multi-component vapour systems by Standart and Krishna using a general matrix models for the multi-component mass transfer with the more accurate model of Standart and Krishna is given for the partial condensation of a ternary vapour system.

Application of a modified Wilson equation to liquid mixtures showing phase splitting

For the design of separation processes, accurate phase equilibrium data are required. Very often experimental data on multicomponent vapour—liquid and liquid—liquid equilibria are not available. It is therefore desirable to be able to predict phase equilibrium behaviour of multicomponent systems using information on the constituent binary data only. In the literature many expressions for the excess Gibbs energy have been reported. Among these the well known Wilson equation (Wilson, 1964) provides a very good representation for a wide variety of completely miscible systems, including strongly non-ideal mixtures. This expression, based on the concept of local composition, only needs binary parameters for calculating multicomponent vapour—liquid equilibria. However, this equation suffers from the limitation that it is not able to predict phase splitting. A modified Wilson equation due to Hiranuma (1975) is discussed in this paper; it is applicable to multicomponent vapour—liquid and liquid—liquid equilibria. This expression contains an additional binary parameter β ij , which has a certain degree of theoretical background. The effect of the parameter β ij on such systems is illustrated by examples. When β ij equals unity, the modified Wilson equation is reduced to the original Wilson equation.

Film condensation of multicomponent mixtures

The classic Nusselt model is generalized for the condensation process of a multicomponent vapor mixture. The condensed vapors may be miscible in their liquid state or contain noncondensable gases. The reduction in the condensation rate owing to the accumulation of a noncondensable gas or the more volatile components near the condensate interface is demonstrated for three component systems of methanol—water—air and acetone—methanol—water. Also the effects of interfacial suction and forced convection are included. The analytical solution incorporates Diffusion Law for a multicomponent system and both exact and approximate integral method solutions are applied. The accuracy of the integral method turns out to be remarkably good.

An analysis of combined surface and volume diffusion processes in crystal growth

An exact solution is obtained to diffusion equations governing the motion of parallel steps on a crystal surface. The model includes simultaneous volume and surface diffusion. The expression for the rate of growth versus supersaturation reduces to a simple relation valid under most experimental conditions. The relations of Burton, Cabrera, and Frank, and of Chernov are derived as limiting cases. The deductions of the theory are applied to experimental data on multicomponent vapor growth and solution growth.