摘要:

AbstractThe rate of absorption into a horizontal liquid layer undergoing an assumed steady cellular convection due to a concentration gradient or to the Marangoni effect is calculated. One concludes that a roll‐cell model can explain the large increase in the rate of absorption observed experimentally and that for large times a diffusional model, with a constant diffusion coefficient much larger than the molecular one, describes adequately the above situation

ISSN:0008-4034    

DOI:10.1002/cjce.5450490112

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1971

数据来源: WILEY

摘要:

AbstractCrystal size distribution data and experimental sorption curves are presented for Linde 4A and 5A zeolites. It is shown that the deviation of the experimental sorption curves from the simple solution of the diffusion equation for spherical particles can be quantitatively accounted for by considering the shape and size distribution of the zeolite crystals. By working with well characterized samples of crystals it is thus possible to obtain reliable diffusivity data for rapid sorption processes by analysis of the sorption curves at intermediate and long times. The concentration dependence of diffusivity is briefly discussed.

ISSN:0008-4034    

DOI:10.1002/cjce.5450490113

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1971

数据来源: WILEY

摘要:

AbstractResults are reported for the formation of ammonium chloride by counter diffusion of ammonia and hydrogen chloride over the temperature range 25 ‐ 40°C. Two modes of precipitation were observed, continuous and periodic precipitation (formation of Liesegang rings). The results establish that the presence of moisture is the important factor controlling the mechanism of precipitation, a minimum moisture content of approximately 100 ppm being required for formation of Liesegang rings. Under these conditions the concentration product was found to be very much greater than the thermodynamic minimum value confirming that nucleation of the solid product regulates the proce

ISSN:0008-4034    

DOI:10.1002/cjce.5450490114

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1971

数据来源: WILEY

摘要:

AbstractAn experimental investigation of the effect of surface energetic heterogeneity on surface diffusion using Vycor and Graphon and as gases ethane, propylene, nitrogen, and helium confirms published reports that surface diffusion proceeds more rapidly on the energetically homogeneous Graphon surfaces. Activation energies for diffusion are found to be about the same for Vycor and Graphon; thus, it is postulated that a major factor in the difference is surface roughness. A comparison of surface diffusion models shows that Fick's Law correlated results about as well as a hydrodynamic model. Both models fail to allow adequately for surface coverage. A comprehensive form of Fick's Law for surface diffusion is proposed.

ISSN:0008-4034    

DOI:10.1002/cjce.5450490115

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1971

数据来源: WILEY

摘要:

AbstractLes auteurs proposent l'utilisation d'un nouveau type d'extracteur dans lequel ils superposent deux agitations, l'une de pulsation, l'autre de rotation. Après avoir étudié les conditions hydrodynamiques de leur appareil, ils comparent ses performances à celles d'appareils plus classiques fonctionnant en continu à contre courant. A l'aide de deux mélanges ternaires, ils ont établi que l'efficacité de leur appareil est supérieure à celle d'une colonne pulsée ou d'une colonne à disques rotatifs: les hauteurs d'unités de transfert sont réduites par un facteur pouvan

ISSN:0008-4034    

DOI:10.1002/cjce.5450490116

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1971

数据来源: WILEY

摘要:

AbstractA 4‐in. diameter controlled cycling extractor using dual flow sieve trays was built and operated successfully on the test system water‐acetic acid‐methyl isobutyl ketone at realistic concentration levels and solute transfer in both directions. The most important parameters of industrial importance, the capacity and efficiency of the column, were studied in detail. Comparisons made with conventional operation show that the efficiency is at least 100% better, and capacity increases of 50% over the flooding point (in conventional operation) or higher are easily obtained. The practical and economic aspects of column operation are discussed. A transient model for a controlled cycling (CC) extractor using the concept of mixing stages was developed. The model predicts the increases in efficiency observed experimentally, and also gives an insight into the control aspects of the CC extr

ISSN:0008-4034    

DOI:10.1002/cjce.5450490117

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1971

数据来源: WILEY

ISSN:0008-4034    

DOI:10.1002/cjce.5450490118

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1971

数据来源: WILEY

摘要:

AbstractSolutions for fixed bed ion exchange based on a linear mass transfer model (linear isotherm and linear driving force rate equation) and general initial and boundary conditions are presented. The linear model solutions are applied to the study of the cyclic operation of fixed bed ion exchange and the equations describing both the transient and cyclic fixed bed processes for co‐current regeneration are derived. Examples which illustrate the simplicity of application of the analytical solutions are discusse

ISSN:0008-4034    

DOI:10.1002/cjce.5450490119

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1971

数据来源: WILEY

摘要:

AbstractExtraction of model parameters, such as kinetic rate coefficients, equilibrium constants and transport rate coefficients, may be obtained by determining the coefficients of the Fourier series which describe chromatographic peaks. Error buildup due to noise occurs slowly with successive harmonics in contrast to the rapid buildup in successive moments which make higher moments unreliable for extracting model parameters. Fourier analysis is applied to the simplest case of axial dispersion in a non‐porous, non‐adsorbing packing and to the important case of adsorption on a porous packing. Expressions for the Fourier coefficients, amplitude ratios and phase lags are derived for the axial dispersion case, the Kubin‐Kucera model for adsorption on a porous packing and, as well, for the case of axial dispersion and inter‐particle diffusion without ads

ISSN:0008-4034    

DOI:10.1002/cjce.5450490120

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1971

数据来源: WILEY

摘要:

AbstractGroup solution models of liquid mixtures have been used previously to predict excess free energies of non‐ideal systems. With increasing experimental data available on heats of mixing, the application of a similar model to excess enthalpies has been investigated. The model allows for both structural and group contributions to excess enthalpies. The former contribution is determined from experimental data on mixtures of alkanes. The group contribution has been determined at 25°C and 45°C for systems containing alkanes and alcohols. Predictions require no experimental data on the system in question, and are in good agreement with experiment. Limited extrapolation to other temperatures and group compositions should be satisfact

ISSN:0008-4034    

DOI:10.1002/cjce.5450490121

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1971

数据来源: WILEY