Showing papers in "Canadian Journal of Chemical Engineering in 1966"

The flow of suspensions through tubes: V. Inertial effects

Abstract: The behavior of particles undergoing Couette and Poiseuille flows at rates when inertial effects become significant was investigated. The rotation of rigid particles was similar to that in the Stokes flow regime, except for a drift of cylinders to limiting rotational orbits corresponding to the maximum energy dissipation. In Poiseuille flow, rigid particles migrated to an equilibrium radial position which depended on the density difference of two phases, the directions of sedimentation velocity and flow, and the ratio of particle to tube radius. Neutrally buoyant deformable particles always migrated to the tube axis. In concentrated suspensions a plasmatic layer developed near the tube wall as a consequence of radial migration. The formation of this layer modified the velocity profile and caused a reduction in the apparent viscosity coefficient. On a fait l'etude du comportement des particules soumises aux ecoulements de Couette et Poiseuille a des vitesses pour lesquelles les effets d'inertie deviennent appreciables. La rotation des particules rigides a ressemble a celle du systeme d'ecoulement de Stokes, sauf qu'il y a eu deviation des cylindres vers des orbites rotatives et limitatives qui correspondent a la dissipation maximum de l'energie. Dans l'ecoulement de Poiseuille, les particules rigides ont passe a une position radiale d'equilibre qui dependait de la difference de densite entre les deux phases, des directions de la vitesse de sedimentation et du courant ainsi que du rapport entre les particules et le rayon du tube. Les particules deformables et flottantes a l'etat neutre se sont toujours deplacees vers l'axe du tube. Dans des suspensions concentrees, il s'est forme une couche plasmastique pres de la paroi du tube comme consequence du transport radial, laquelle a modifie le profil de la vitesse et diminue le coefficient de viscosite apparente.

Surface diffusion in microporous media

Abstract: The surface diffusion of He, Ne, H2, Ar, O2, N2 and CO2 through Vycor microporous glass was analyzed theoretically and experimentally in the low pressure range as a function of temperature. A statistical-mechanical treatment was carried out in terms of partition functions to derive a general equation of surface flow. It was possible to separate the surface diffusion from the total flow using a simplified working equation. The conventional method which assumes that there is no adsorbed flow for helium should be discarded, because the fraction of surface diffusion for helium ranges from 0.133 to 0.247. It is also illustrated how to predict the permeability of a new gas for the same porous medium. La diffusion de surface des gaz He, Ne, H2, Ar, O2, N2 et CO2 au travers d'un verre microporeux de type Vycor a ete analysee theoriquement et experimentalement en function de la temperature pour de faibles pressions. On a derive une equation generale d'ecoulement de surface a l'aide d'une methpde statistique-mecanique. On a aussi separe la diffusion de surface de l'ecoulement total a l'aide d'une relation simplifiee. On a determine que la fraction de diffusion de surface pour l'helium varie de 0.133 a 0.247, ce qui nous porte a dire que la methode conventionnelle utilisee pour l'helium est fausse. On montre comment il est possible de predire la permeabilite d'un nouveau gaz pour le měme milieu poreux.

Optimal continuous fermentation reactor design

Abstract: Many optimum reactor combination schemes have been proposed for fermentation (autocatalytic) reaction systems. Usually these consist of series of stirred tanks or plug flow vessels. The basis for choosing an optimal scheme is here presented and it is found that for many cases of interest the combination of stirred tank - plug flow is the best. On a propose un grand nombre de combinaisons qui conviendraient le mieux aux reacteurs dans le cas des systemes a reaction (autocatalytiques) pour fermentation; d'ordinaire, il s'agit d'une serie de reservoirs munis d'agitateurs ou de vaisseaux a ecoulement en bloc. On indique les facteurs fondamentaux a considerer dans le choix du meilleur dispositif et l'on a trouve que, dans bien des cas interessants' l'emploi conjoint de reservoirs munis d'agitateurs et d'ecoulement en bloc est la meilleure solution.

Correlation of pressure gradients for the stratified laminar‐turbulent pipeline flow of two immiscible liquids

Abstract: The parameters introduced by Lockhart and Martinelli to correlate pressure gradients accompanying the flow of gas-liquid mixtures in horizontal pipes have been found to be useful in correlating data for the stratified flow of two immiscible liquids in the laminar-turbulent regime. Curves through liquid-liquid data available from three different sets of experiments, though being significantly displaced from the Lockhart-Martinelli curves for gas-liquid systems, represent the data with a maximum deviation of approximately 24%. Les parametres introduits par Lockhart et Martinelli pour obtenir une correlation des gradients de pression qui accompagnent l'ecoulement de melanges gaz-liquides dans des tuyaux horizontauz ont ete utilises avec avantage pour obtenir une correlation des donnees obtenues avec avantage pour obtenir une correlation des donnees obtenues avec l'ecoulement stratifie de deux liquires immiscibles. Bien qu'elles soient deplacees appreciablement des courbes Lockhart-Martinelli pour des systemes gaz-liquide, les courbes obtenues avec les donnees liquide-liquide pour trois differentes series d'experience accusent une deviation maximum d'environ 24%.

Particle trajectories and terminal velocities in vertically oscillating fluids

Abstract: The trajectories and terminal velocities of particles in vertically oscillating fluids have been studied by obtaining analytic and numerical solutions to the nonlinear Langevin equation representing a superposition of forces arising from particle acceleration, displaced fluid acceleration, buoyancy and particle-fluid drag as represented by an nth-power drag law. In vibrating fluids the directional particle velocities are found to be lower than in stationary fluids for drag exponents n > 1 and correspondingly higher for 0 < n < 1. The engineering significance of the results is discussed in relation to hold-up, separation and transport phenomena in vertically oscillating multiparticle-fluid systems. On a etudie les trajectoires et vitesses limites de particules dans un fluide sous oscillation verticale en obtenant des solutions numerique et analytique a l'equation non-lineaire de Langevin. Cette derniere represente une superposition des forces provenant des accelerations de la particule et du fluide deplace, de l'immersion et de la friction de la particule dans le fluide (relation de coefficient de trainee a la puissance n). Les vitesses directionnelles de la particule, dans un fluide sous vibration, sont moindres que celles dans un fluide stationnaire si n > 1 et plus grandes si 0 < n < 1. On discute de la signification des resultats obtenus en relation avec les phenomenes de circulation et de separation dans des systemes fluides-particules avec oscillation verticale.

Vapor‐liquid equilibrium data for system: Ethanol‐water saturated with potassium acetate

Abstract: : Isobaric vapor-liquid equilibrium data at atmospheric pressure are reported for the system ethanol-water saturated with potassium acetate. Solubility data for potassium acetate in boiling solutions of aqueous ethanol, as a function of ethanol concentration, are also reported. Potassium acetate, a salt highly soluble in aqueous solution, was observed to exert a very large effect on relative volatility. (Author)

Heat transfer to agitated non‐newtonian fluids

Abstract: Heat transmission to agitated non-Newtonian liquids in a jacketed vessel has been studied. Heat transfer tests were conducted under unsteady-state conditions with pseudo-plastic solutions (behavior index range: 0.343 to 0.633). For a generalized Reynolds number ranging from 100 to 5000, two correlations were found: The use of a generalized Sieder and Tate number resulted in an equation combining both heating and cooling data with a somewhat higher mean deviation (19.3%): Nous avons etudie le transfert de chaleur en regime d'etablissement a des fluides non-Newtoniens dans un reservoir a chemise chauffante avec agitation. Des solutions pseudoplastiques dont l'indice de comportement viscosimetrique varie de 0.343 a 0.633 ont ete utilisees. Deux relations, valides pour des nombres de Reynolds generalises variant de 100 a 5000, ont ete determinees: Nous avons combine ces deux equations en utilisant le nombre de Sieder & Tate generalise mais la deviation moyenne est plus elevee, soit 19.3%:

Discrimination between two rival models through nonintrinsic parameters

Abstract: In analyzing data from heterogeneous reactions, it is often necessary to quantitatively compare the relative ability of two rival models to fit the data. For Hougen-Watson models, techniques exist for comparing this degree of fit for low conversion data; a method is suggested here for making quantitative comparisons using high as well as the low conversion data. Once estimates of the parameters in the two models are obtained, the method may be applied by a one-variable regression analysis. An example is presented illustrating the advantages of using all the conversion data in discriminating between two rival models. En analysant les resultats provenant de reactions heterogenes, il faut souvent comparer quantitativement l'aptitude de deux modeles rivaux a y satisfaire. Dans le cas des modeles Hougen-Watson, il y a moyen de comparer leur degre de convenance, lorsqu'il s'agit d'une transformation faible. On suggere un procede pour faire des comparaisons quantitatives, qu'il s'agisse de transformation forte ou faible. Apres avoir evalue les parametres dans le cas des deux modeles, on peut appliquer la methode d'analyse regressive a une variable; un exemple illustre l'avantage d'employer toutes les donnees de transformation pour choisir entre deux modeles rivaux.

Gas absorption in horizontal cocurrent bubble flow

Abstract: Cocurrent flow pipeline reactors would have several advantages for gas-liquid reacting systems. However, design data are lacking, particularly for absorption rates of gas. The present study was purely exploratory, for the purpose of obtaining the first data on liquid-phase controlled absorption of gases in horizontal cocurrent two phase flow. CO2 and helium were used as gases and water, ethanol and ethylene glycol as liquids over a wide range of operating conditions. The data in the bubble and plug flow regions have been correlated by an equation based on qualitative observation and analogy to the case of a single flowing fluid. The resulting expression, reproduces most bubble flow data to ± 15%, and includes the effects of gas and liquid flow rates, pipe diameter, surface tension, liquid viscosity and diffusivity.

Combustion of aniline droplets at high pressures

Abstract: The combustion of aniline droplets is well described by the “d2 law” up to about 200 psia. At higher pressures turbulence and flame opacity prevent the reliable measurement of droplet diameter but the burning mechanism appears not to change as long as the pressure is less than the critical pressure of aniline. Above the critical pressure of aniline a completely different combustion mechanism is observed. La combustion de gouttelettes d'aniline est bien decrite par la “loi d2” jusqu'a une pression de 200 psia; a des pressions plus elevees, la turbulence et l'opacite de la flamme empechent le mesurage precis du diametre des gouttelettes, mais le mecanisme de combustion ne semble pas changer tant que la pression est inferieure a celle de la pression critique de l'aniline. Au-dela de la pression critique de l'aniline, on observe un mecanisme de combustion tout a fait different.

Viscosities of binary mixtures in the dense gaseous state: The methane-carbon dioxide system

Abstract: Viscosity measurements for the gaseous state of three binary mixtures of the methane-carbon dioxide system were carried out at 50, 100, 150 and 200 °C. for pressures ranging from 34 to 680 atm. The compositions of these mixtures were 0.243, 0.464 and 0.755 mole fraction methane. These measurements were made using an unsteady state capillary viscometer which had been used previously in the procurement of viscosities of pure substances. The resulting measurements for these mixtures produced relationships between μ-μ* and ρ which were consistent in behavior with the corresponding relationships of the pure constituents of this binary system. When these variables were normalized with ϵ the viscosity parameter, and ρc, the critical density, the quantities (μ-μ*)ϵ and ρR for these mixtures and the pure components yielded a single relationship which can represent the viscosity behavior for this entire binary system.

Extrapolation of ternary excess thermodynamic properties

Abstract: A method, based on the Gibbs-Duhem equation, is proposed for extrapolating ternary excess thermodynamic properties over the complete concentration range. For those thermodynamic properties whose three excess partial molal quantities at a given composition can be directly evaluated from a single measurement, such as excess Gibbs free energy of mixing, 4 ternary experimental points are required. For those thermodynamic properties whose three excess partial molal quantities at a given composition cannot be directly evaluated from a single measurement, such as excess enthalpy of mixing, 7 ternary experimental points are required. In both cases necessary binary data are assumed to be available. Experimental heat of mixing data for the systems ethanol-n-heptane, n-heptane-benzene and ethanol-n-heptane-benzene at 25°C. are also reported. On propose une methode basee sur l'equation de Gibbs-Duhem pour l'extrapolation des proprietes thermodynamiques et ternaires excedant celles d'un melange ideal, pour toute la marge des concentrations. Dans le cas des proprietes thermodynamiques dont on peut evaluer directement, par simple mesurage, trois quantites molaires, partielles et excedent l'ideal, pour une composition donnee (comme c'est le cas de l'energie libre excedente de melange de Gibbs), il faut 4 points ternaires experimentaux. Lorsqu'il s'agit de proprietes thermodynamiques dont on ne peut evaluer directement les memes quantites d'une maniere semblable (comme c'est le cas d'une enthalpie excedente de melange), il faut 7 points ternaires experimentaux. On suppose que, dans les deux cas, les donnees binaires necessaires sont disponibles. On fournit egalement des donnees experimentales sur la chaleur du melange a 25°C dans le cas des systemes ethanol-n-heptane, n-heptane-benzene et ethanol-n-heptane-benzene.

Mass transfer from bubbles in cocurrent flow

Abstract: An experimental study has been made of liquid phase mass transfer from bubbles travelling cocurrently with liquid in a horizontal pipe. A simple model of the process based on streams of spherical bubbles has been developed and solved in the form of fractional absorption as a function of dimensionless groups. The derivation of and results obtained from this model are presented and explained. Experimental absorption rates measured in turbulent liquid flow over very wide ranges of bubble frequencies support the predictions of this model. A very effective bubble-frequency counter has also been developed capable of counts as high as 1600/min. On a fait une etude experimentale de la separation en masse d'une phase liquide des bulles gazeuses qui se deplacaient avec celui-ci dans un tuyau horizontal. On a mis au point un modele simple du procede base sur les courants de bulles spheriques et realise la separation sous forme d'absorption fractionnee en fonction de groupes sans dimensions. On indique et explique les resultats obtenus a partir du dit modele. Les vitesses experimentales d'absorption, mesurees dans le flot liquide et turbulent pour une grande variete de frequences de bulles, appuient les predictions apportees par ce modele; on a mis au point un compteur de frequence des bulles qui est tres efficace et peut aller jusqu'a 1600/minute.

Preparation of urania and urania--zirconia microspheres by a sol-gel process.

Abstract: The sol-gel process was originally developed and applied at the Oak Ridge National Laboratory for preparation of high-density thoria-urania fragments and microspheres for nuclear reactor fuels. The application of the process for preparation of microspheres to sols of urania, urania-zirconia, and urania-carbon is reported in this paper. Relatively high-strength, spherical particles of UO2, UO2-ZrO2, and UC2 were prepared with diameters of 50-500 microns and densities of 80-100% of the theoretical densities. Le procede dit sol-gel a ete originairement mis au point et utilise au Laboratoire national d'Oak Ridge pour la preparation de fragments et de microspheres de thorine et d'urane pour les combustibles des reacteurs nucleaires. On rapporte dans le present travail l'application du dit procede servant a la preparation de microspheres a des sols d'urane-zircone et d'urane-carbone. On a prepare des particules spheriques d'UO2, UO2-ZrO2 et UC2 qui possedaient une resistance relativement elevee, des diametres de 50-500 microns et des densites atteignant 80 a 100% des valeurs theoriques.

Mass transfer in a turbulent radial wall jet

Abstract: Experimental and theoretical coefficients are reported for mass transfer in a turbulent radial wall jet initiated by an impinging free jet. The hydrodynamic solution was obtained by the momentum integral technique, and mass transfer was predicted by analogy. Point mass transfer data were obtained for air-naphthalene and cinnamic acid-water systems. At low Schmidt numbers, experimental coefficients were slightly above the theoretical prediction, and followed the theoretical trend with radial distance and nozzle Reynolds number from 10,000 to 60,000. Coefficients at high Schmidt numbers showed large positive deviations from theory, which decreased with radial distance and increased with Schmidt number. These discrepancies were attributed to surface roughness effects.

Experimental study of natural convection heat transfer in a non‐newtonian fluid: Part II. Horizontal plate

Abstract: Experimental data of natural convection heat transfer from a heated horizontal plate, both facing upward and downward, to a non-Newtonian fluid are reported. Empirical expressions essentially similar to those developed for the vertical plate case are obtained which correrlate the data with reasonable accuracy. Les donnees experimentales sur le transfert de chaleur par convection naturelle a un fluide non-newtonien depuis une plaque horizontale chauffee sont presentees. Les expressions empiriques obtenues sont essentiellement similar res a celles deja obtenues pour le cas de la plaque verticale.

Surface adsorption and the effect of column diameter in the continuous foam separation process

Abstract: Foam separation has been investigated as a technique for removing ethylhexadecyldimethylammonium bromide, a cationic surfactant, from dilute solutions. An ideal foam model has been used to determine the surface excess accumulated at the solution-air interface and to predict the foam and drain concentration in a continuous foam separation process. It was found that the model was valid only under conditions of good drainage and perfect foam stability. An increase in column diameter for a feed of constant composition and supplied at a constant rate increased the concentration of the surfactant in the overhead stream. This highly desirable effect was accompanied by an increase in the drain rate. The results indicate that an increase in column diameter had an entirely beneficial effect on the efficiency of the separation. La technique de separation par moussage a ete etudiee pour l'extraction du bromure d'ethylhexadecyldimethylammonium a partir des solutions diluees de cet agent tensio-actif cationique. Un modele de mousse ideal a ete utilise pour la determination de l'exces superficiel a l'interface solution-air et pour la prediction de la concentration du produit de těte et de l'effluent dans une operation continue de separation par moussage. II a ete conclu que la validite du modele est limitee aux conditions de bon drainage et de parfaite stabilite de la colonne de mousse. Pour une alimentation de composition et de debit constants, l'augmentation du diametre de la colonne a pour effet d'augmenter la concentration du produit de těte ainsi que le debit de l'effluent. Les resultats indiquent que l'augmentation du diametre de la colonne a un effet avantageux sur le rendement.

Some observations on heat transfer to agitated liquids

Abstract: Heat transfer coefficients for agitated liquids in a flat-bottomed vessel equipped with a heating coil have been measured over wide ranges of Prandtl and Reynolds numbers in order to examine the effect of coil surface, impeller design and coil geometry. The study of impellers included a comparison of flat-bladed and pitched-bladed agitators. Helical and baffle coil geometries were tested using smooth, knurled and finned tube surfaces. For all systems studied the Reynolds number exponent was observed to be dependent on viscosity. The data for finned tubes indicated higher transfer rates due to increased surface area and wall-turbulence. Les coefficients de transmission de la chaleur pour des liquides soumis a une agitation, dans un vaisseau a fond plat et muni d'un serpentin de chauffage, ont ere mesures sur une grande echelle de nombres de Prandtl et de Reynolds, afin de determiner les effets de la surface du serpentin, du genre de construction de la roue a aubes et de la forme geometrique du serpentin. L'etude des roues a aubes a inclus une comparaison entre des agitateurs a palettes plates et inclinees. On a fait les essais relatifs a la forme geometrique (helicoidale ou a chacanes) du serpentin en utilisant des tubes dont la surface etait lisse, moletee et a ailettes. Dans tous les systemes etudies, l'exposant du nombre de Reynolds a paru dependre de la viscosite. Les result als obtenus dans le cas des tubes a ailettes ont indique qu'ils permettaient l'obtention de vitesses de transmission plus elevees a cause de l'accroissement de l'aire de la surface et de la turbulence a la paroi.

Momentum and heat transfer characteristics of liquid-liquid dispersions in turbulent flow

Abstract: The momentum and heat transfer characteristics of unstable, liquid-liquid dispersions flowing turbulently in a circular tube were investigated. Two mineral oils, a light oil with viscosity of 15 centipoise, and a heavy oil with viscosity of 200 centipoise were used as the dispersed phase while the continuous phase was tap water. At room temperature only, the relative fluidity of the dispersion follows the relation At Reynolds numbers above 60,000 the heat transfer coefficients of all dispersions studied follow the relation where the Prandtl number is that of the continuous phase and the Reynolds number is based upon the viscosity of the dispersion. All properties are evaluated at the film temperature. On a etudie le moment et les caracteristiques de transfert de la chaleur dans le cas de dispersions instables d'un liquide dans un liquide, qui produisent un ecoulement turbulent dans un tube circulaire, On a employe a cette fin deux huiles minerales (une legere et une lourde de viscosite respective de 15 et 200 centipoises) comme phase dispersee et de l'eau de robinet comme phase continue. A la temperature de la chambre seulement, la fluidite relative de la dispersion correspond au rapport suivant: Lorsqu'il s'agit de nombres de Reynolds depassant 60,000, les coefficients de transmission de la chaleur, pour toutes les dispersions etudiees, suivent l'equation suivante: ou le nombre de Prandtl est celui de la phase continue, tandis que le nombre de Reynolds est base sur la viscosite de la dispersion. On a evalue toutes les proprietes a la temperature de la pellicule.

Impact tube measurement of flow patterns, velocity profiles and pumping capacities in mixing vessels

Abstract: Impact-static-shielded tubes were found to be suitable for measuring time-average velocities in the jet stream flow generated by the marine propeller. Pumping capacities and entrainment flow were then calculated from these velocity profiles. Pumping capacities were correlated by: Q = KpND3. When the tank contained water: Kp = 0.54. The same probe was found to be useful in evaluating qualitatively the flow patterns from turbine and paddle type impellers. The effect of several parameters on the flow patterns are reported.

Dissociation and heat transfer in laminar flow

Abstract: An analytic study of heat transfer and temperature and composition distribution was conducted for a reacting fluid in laminar flow in a tubular reactor. The reaction chosen was reversible and homogeneous of the form A ⇆ 2U. Numerical solutions were obtained by machine computation for conditions of chemical equilibrium and of finite kinetics. For endothermic, dissociative reactions the radial energy transfer due to diffusion adds to the contribution due to a temporary difference. Nusselt numbers up to 10 fold greater than those for the corresponding inert system are obtained. The diffusion contribution is a maximum when the radial mass transfer is not subject to a reaction resistance; i.e. at equilibrium. On a analyse le transferl de chaleur et la distribution de temperature et composition d'un reactif fluide en ecoulement laminaire dans un reacteur tubulaire. La reaction etudiee est reversible et homogene de la forme A ⇆ 2U. Les solutions numeriques ont ete obtenues pour les conditions d'equilibre chimique et de vitesse de reactions limitees. Pour des reactions endothermiques et dissociantes, le transfert radial d'energie cause par la diffusion s'ajoute a la contribution provenant de la difference de temperature. On obtient des nombres de Nusselt jusqu'a 10 fois superieurs a ceux pour des systemes similaires mais inertes. L'effet cumulatif de la diffusion est maximum lorsque le transfert de masse radial n'est pas affecte par une resistance due a la reaction; c'est-a-dire a l'equilibre.

The thermal history of a granule in a rotary cooler

Abstract: A formula is developed (from which a computer program has been written) that allows the temperature to be calculated of a granule that undergoes alernating periods of being cooled and of being allowed to ‘soak’ without cooling. This is the process, repeated many times, that a particle suffers in a rotary cooler. The result should provide a design method that utilizes only basic physical quantities. La temperature d'une granule qui subit des cycles alternatifs de refroidissement et d'attente, typiques au processus dans un sechoir rotatif, peut ětre calculee a l'aide d'une formule pour laquelle une programmation a ete etablie. Le resultat devrait permettre une methode de calcul des sechoirs rotatifs qui n'utilise que des quantites physiques fondamentales.

The characteristic dimension in scraped surface heat transfer

Abstract: Previous published work on scraped surface falling film heat exchangers has used the tube diameter as the characteristic dimension. The present investigation confirms that in such equipment the liquid is carried as a fillet, roughly triangular in shape in front of the blades. Using an equivalent diameter based on flow area of the fillet and the length of the are in contact with the transfer surface, a correlation based on earlier results is developed which is independent of tube diameter, except in defining the rotary inertia forces. The refined correlation is:—

A simulation and parametric study of four existing multi‐component distillation columns

Abstract: The Θ-method and block-relaxation method of solving The non-linear set of algebraic equations which describe the leady-state behavior of standard distillation columns are compared. The results from the mathematical models are compared with actual plant performance of a depropanizer, debutanizer, de-ethanizer, and ethane-ethylene splitter. Column section efficiencies are tabulated. A parametric study of the variation of feed condition, reflux condition and flow, and feed tray location was made on these columns and the responses of the key component concentrations have been mapped. Such a study permits improvement of current plant operation. Its use for design of more efficient columns and arranangements is indicated. On compare la methode-Θ avec celle de la detente des blocs pour resoudre la serie non-lineaire d'equations algebriques, ou I'on decrit le rendement constant des colonnes normales a distillation. On compare les resultats provenant de modeles mathematiques avec le rendement reel d'usines pour eliminer le propane, le butane et l'ethane et separer l'ethane de l'ethylene. Les rendements des sections de colonnes apparaissent sur un tableau. On a fait sur ces colonnes une etude parametrique de la variation des conditions d'alimentation, du flux et du reflux ainsi que l'endroit ou se trouve le plateau d'alimentation, et transpose sur carte les reponses des concentrations des principaux elements. L'etude precitee permet d'ameliorer le fonctionnement normal de l'usine et son emploi est indique pour la conception de colonnes plus efficaces et autres arrangements.

Solubility parameters of hydrocarbons

Abstract: Information available in the literature on vapor pressures, saturated vapor and liquid densities, and critical constants, for different hydrocarbons, has permitted the calculation of δ, the solubility parameter advanced by Hildebrand, at temperatures up to and including the critical point. For these hydrocarbons, the residual quantity, δ-δc was found to depend on 1-TR according to the relationship, where k appears to be a constant within different classes of hydrocarbons. Values of δ calculated with this equation were compared with the corresponding values used to develop it, and produced an average deviation of 0.85% for 153 values considered which represented 17 hydrocarbons.

The mixing of solid particles in a fluidized bed

Abstract: In this paper a new experimental method, based on the freezing of the fluidized bed by the aid of paraffin wax is used for the determination of the diffusion coefficient of the solid particles. The experimental diffusion coefficients are compared with those given by a theoretical equation. In order to explain the time and spatial dependence of the experimental diffusion coefficient a cinematographic study supplemented by visual observations is also made. One concludes that for small tube diameters a circulation motion of the solid particles takes place which is responsible for the mentioned effect. Cet article presente une nouvelle methode experimentale pour determiner le coefficient de diffusion de particules solides en figeant un lit fluidise a l'aide de paraffine. Ces coefficients experimentaux sont compares a ceux obtenus theori-quement. Une etude cinematographique, complementee d'observations visuelles, est utilisee pour expliquer la dependance dans le temps et l'espace des coefficients de diffusion experimentaux. Un mouvement circulatoire de la particule solide dans les tubes de faibles diametres est responsable de l'effet mentionne.

Solution of problems involving systems of distillation columns

Abstract: A convergence method (called the Θ-method) and calculational procedure have been developed which may be applied to any system of distillation units. The procedure makes use of the programs of the individual units without modification. This amounts to the use of the programs of the individual units as building blocks for the construction of the model for the system. Any number of independent feeds to any one of the distillation units may be specified, and any number of sidestreams may be either withdrawn from the system or fed to any other unit of the system.