bluuebunny/crossref_metadata_2025_split huggingface dataset:
Equilibrium flow of a general fluid through a cylindrical tube
Authors: Sakiadis B. C. 
Published: June 2004

AbstractEquilibrium flow of a general fluid through a long, straight, cylindrical tube is examined, and equations are derived for determining the three pertinent material functions, the shear stress component, the difference between the radial and angular normal stress components, and the difference between the axial and angular normal stress components. These equations are expressed in terms of quantities which are measurable. Experimental data are obtained for a polymer solution, and the material functions are calculated.
Binary liquid diffusion coefficients
Authors: Kamal Musa R. , Canjar L. N. 
Published: June 2004

AbstractThe present work proposes a new approach for the calculation of the diffusion coefficients in binary liquid systems. The proposed equation is based on the results obtained by statistical mechanics of transport phenomena in dense media. It does not include viscosity explicitly, and the variables required for the calculation are fundamental in nature; these are the free volume of a molecule obtainable from physical measurements such as velocity of sound and the heat of vaporization of the solute. In spite of its theoretical background, the proposed correlation obtains results on fifty‐six different solute‐solvent systems with about 13% deviation from the experimental results. The effect of concentration on the diffusion coefficient is very easy to determine and is more in accord with experimental results than can be predicted by other available correlations.
Spontaneous interfacial cellular convection accompanying mass transfer: Ethylene glycol‐acetic acid‐ethyl acetate
Authors: Orell Aluf , Westwater J. W. 
Published: June 2004

AbstractSpontaneous interfacial cellular convection accompanying the extraction of acetic acid out of ethylene glycol with ethyl acetate was studied photographically with a Schlieren technique. A flat liquid‐liquid interface at room temperature was photographed straight down with motion‐picture and still cameras. The interface exhibited a dominant pattern of stationary and propagating polygonal cells, accompanied by stripes, cell cluster boundaries, and confined or unconfined ripples. The time‐dependence of the average wave length (size) of the different patterns, their average speed of propagation, and their frequency was determined by means of an initial acetic acid concentration range of 0.1 to 10%, over a time span of 72 hr. The average wave lengths of cells, stripes, and ripples ranged from 0.02 to 0.14, 0.065 to 0.155, and from 0.03 to 0.10 cm., respectively. Cell and ripple velocities ranged from 0.27 to 1.33, and from 0.27 to 1.10 cm./min. respectively.The relation between the observed interfacial cellular convection and the Sternling‐Scriven theory of interfacial turbulence is discussed.
A reduced state vapor‐pressure relationship and its application to hydrocarbons
Authors: Reynes Enrique G. , Thodos George 
Published: June 2004

AbstractThe Frost‐Kalkwarf vapor‐pressure equation has been modified to include as variables the reduced temperature and pressure of the substance. The resulting relationship was found to contain a universal constant δ = 0.1832 and three other constants α, β, and γ, which are characteristic of the substance. Relationships between α, β, and γ were found to exist, and thus a vapor‐pressure equation was produced which contains only one characteristic contant β and which is capable of predicting vapor pressures of pure substances up to the critical point.This vapor‐pressure relationship has been applied to hydrocarbons of all types, including normal paraffins, isoparaffins, olefins, diolefins, acetylenes, naphthenes, and aromatics. In these calculations values of β were estimated from the molecular structure of the hydrocarbons. For hydrocarbons the approach developed in this study was found to reproduce experimental vapor pressures with an average deviation of 2.7% for 456 experimental points representing fifty four hydrocarbons.This study indicates that if reliable vapor‐pressure data, however meager, are available for a hydrocarbon, these data can be used to obtain constants which enable the prediction of the critical temperature and the critical pressure of the substance.
Reduction of iron oxide in gas‐conveyed systems
Authors: Themelis N. J. , Gauvin W. H. 
Published: June 2004

AbstractThe model particles were prepared by oxidation of carbonyl iron spheres, followed by fractionation into cuts of very narrow size. A two‐wavelength radiation pyrometer was developed for measuring the temperature of the particles in flight, and special probes were designed for determining gas velocity and degree of reduction at different levels of the reactor.
Adsorption of methane and hydrogen on packed beds of activated carbon
Authors: Geser John J. , Canjar Lawrence N. 
Published: June 2004

AbstractThe adsorption of methane from mixtures of methane and hydrogen on fixed beds of activated carbon at −115°F. and 1 atm. has been studied. Inlet gas concentrations of 5.69, 7.58, and 10.65 mole % methane in hydrogen were employed over a gas flow rate range of from 3.24 to 16.3 std. cu. ft./hr. Activated carbon in sizes of 4 × 6 and 6 × 16 mesh and as 1/8‐ and 3/16‐in. pellets were employed as adsorbent.The external diffusion of adsorbate to the surface can be correlated by the usual mass transfer expressions for packed beds, although coefficients obtained in this work are lower than those reported for other systems in the literature.A new equation is presented for internal particle diffusion.
Liquid phase activity coefficients and standard state hypothetical liquid fugacities for hydrocarbons
Authors: Hoffman Dwight S. , Welker J. Reed , Felt Rowland E. , Weber James H. 
Published: June 2004

AbstractOne method of predicting vaporization equilibrium ratios for the components of a multicomponent mixture is through the use of standard state liquid fugacities, standard state vapor fugacities, liquid phase activity coefficients, and vapor phase activity coefficients. The relationship among these variables will be shown.It is the purpose of this paper to present a method for evaluating the fugacities of the components of a multicomponent liquid mixture which is in equilibrium with its vapors; to present a method for evaluating the standard state fugacities of hypothetical liquids and to disclose these values for methane and ethane up to a reduced temperature of 1.6 and values for propane up to a reduced temperature of 1.3; to present the coincident derived values of the vaporization equilibrium constants, Z factors, and solubility parameters; and to show correlations of these values.
Power requirements and blend times in the agitation of pseudoplastic fluids
Authors: Godleski E. S. , Smith J. C. 
Published: June 2004

AbstractAgitation and blending studies were made with solutions of Natrosol 250H, which were pseudoplastic fluids with nonconstant flow‐behavior indexes. The published power number‐Reynolds number correlation for pseudoplastic fluids having constant flow‐behavior indexes is valid for Natrosol solutions. Published correlations for blend times in Newtonian fluids do not apply to Natrosol solutions; the blend times are ten to fifty times longer than with Newtonian fluids of the same apparent viscosity. Blend times are shortest in unbaffled vessels when a vortex is formed and correlate well with the vortex depths. Insertion of radial baffles always lengthened the blend time.
Interrelation of packing and mixed phase flow parameters with liquid residence time distribution
Authors: Glaser M. B. , Lichtenstein Ira 
Published: June 2004

AbstractBrine‐air and kerosene‐hydrogen systems were used for the mixed phase tests. No specific gas phase effects were detected. The measured variability, encompassing all three flow mechanisms, correlated well with particle Reynolds number for each system and decreased with increasing flow rate. However the variability component resulting solely from bulk liquid flow through the main bed channels was found to be relatively constant over a wide range of Reynolds number and independent of whether the bed was uniformly packed or contained large packing faults. The significance of these results to liquid‐solids contacting efficiency is discussed.
Pressure drops in the flow of gases through packed and distended beds of spherical particles
Authors: Wentz Charles A. , Thodos George 
Published: June 2004

AbstractPressure drop measurements were made across packed and distended beds having five layers of smooth plastic spheres, 1.23 in. in diamter, arranged in cubic, body‐centered cubic, and face‐centered cubic orientations of void fractions varying from 0.354 to 0.882. The distended beds were prepared by separating the spheres with permanently attached short lengths of fine rigid wire. Friction factors were calculated from the overall pressure drop measurements with the Ergun equation and were plotted against the corresponding modified Reynolds number which ranged from 2,550 to 64,900. A single relationship resulted for both types of beds which is independent of the geometric orientation and void fraction of the spheres of the bed.To eliminate entrance and exit effects of the air flowing through the bed pressure drop measurements were also made across the middle layer of each distended bed. Again a single relationship between the corresponding friction factors and modified Reynolds number was obtained which is independent of the geometric orientation and void fraction of the bed.From the two relationships between friction factors and modified Reynolds number the ratio Pk/fk for a packed or distended bed having five layers of spheres is 1.13. This ratio should decrease with increasing number of layers of spheres and approach the limiting value of 1 when the number of layers becomes very large.
Dispersed phase mixing: II. Measurements in organic dispersed systems
Authors: Miller R. S. , Ralph J. L. , Curl R. L. , Towell G. D. 
Published: June 2004

AbstractWhen two liquid phases are contacted in a stirred tank reactor, dispersed phase mixing can affect average reaction rate and product selectivity in nonfirst order or mass transfer controlled reactions, as shown theoretically in Part I. This work is concerned with experimental measurement of the dispersed phase mixing rate. Various organic phase dispersions in water were studied in stirred tanks with a dye transfer light transmission technique. Batch experiments were performed in 0.30, 5.5, and 86‐gal. vessels. The variables studied were power input per unit volume, phase fraction, impeller type, and vessel scale. Dispersed phase mixing rates were found to be in the range where they can have significant effects on chemical reactions. A typical value of the mixing rate is 10 volumes of dispersed phase/min. at a power input of 10 hp./1,000 gal. The information given here and in Part I shows for the first time the importance of these effects in reactor design.
Enthalpies of methane‐light hydrocarbon binary mixtures in the vapor phase
Authors: Edmister Wayne C. , Yarborough Lyman 
Published: June 2004

AbstractThe isothermal effects of pressure and composition on the mixture and partial enthalpy differences of the methane‐propane binary were derived from PVTy data. A graphical and numerical technique was used to derive the enthalpy differences from 100° to 460°F. and 200 to 2,000 lb./sq. in. abs. for the complete composition range of the binary.The isothermal effects of pressure and composition on the mixture enthalpy data of the methane‐propane binary were also calculated with the Benedict‐Webb‐Rubin and the Redlich‐Kwong equations of state. The results of the three methods of calculation are compared. The comparison showed that the two‐constant Redlich‐Kwong equation of state is as good as the eight‐constant Benedict equation of state in the superheated vapor region.The data derived in this work were combined with other methane binary enthalpy data from the literature to construct a general correlation of the effect of pressure and composition on the enthalpy of methane‐light hydrocarbon binaries. The correlating parameters are the pseudo reduced temperature and pressure and a mole‐average acentric factor.
Optimum effectiveness factors for porous catalysts
Authors: Cunningham R. E. , Smith J. M. 
Published: June 2004

AbstractIn the manufacture of catalyst pellets from particles of powder, for example alumina, one of the parameters is pellet density. The opposing effects of density on surface available for reaction and on pore diffusion result in a specific pellet density for maximum reaction rate per unit volume of reactor. The method for predicting the optimum density and rate is presented for a first‐order reaction. The data required are pore volumes and pore‐size distributions as a function of density, as well as kinetic measurements. Such data are available for the ortho‐para hydrogen reaction using a nickel oxide‐on‐alumina catalyst. Using this system as an illustration, it can be seen that the optimum effectiveness factors are less than unity and range from about 0.68 for 1/8‐in. diam. spherical catalyst pellets to 0.29 for 1‐in. pellets. Corresponding optimum densities are from about 1.3 to 0.6 g./ccThe results demonstrate the possibility of a tailor‐made pelleted catalyst for optimum reaction rate.
Performance of packed columns VII. The effect of holdup on gas‐phase mass transfer rates
Authors: Shulman H. L. , Savini C. G. , Edwin R. V. 
Published: June 2004

AbstractTo account for the differences in the gas‐phase mass transfer coefficients obtained by the use of vaporization and absorption techniques, data were obtained for ring and saddle packings in a 12‐in. diam. column employing water vaporization and methanol absorption. The ratio of the vaporization to absorption coefficient, corrected for differences in diffusivity, is found to be directly proportional to the ratio of the total holdup to the operating holdup in confirmation of the proposed model in which the effective interfacial area for each type of operation is proportional to the holdup of the liquid active for that operation.
Diffusion resistances in alumina and silica catalysts
Authors: Rao M. Raja , Smith J. M. 
Published: June 2004

AbstractReaction‐rate measurements were made for the ortho‐para hydrogen conversion at −196°C. at 1 atm. pressure with nickel oxide catalysts using alumina and silica gel as carriers. Data were obtained for fine particles for which pore‐diffusion resistances were negligible, for large particles of silica catalysts containing only micropores, and for alumina pellets containing both micro‐ and macropores. From these data experimental effectiveness factors were evaluated.Theoretical effectiveness factors predicted by using a previous theory (7) agreed well with the experimental results. The application of the theory requires pore‐geometry data. The measurement of these data and their use in predicting diffusion resistances are illustrated by experimental data and calculations for the several catalysts. It is shown that a satisfactory method of predicting the significance of diffusion within porous catalysts requires information on the pore volume and pore sizes.
Experimental study of laminar flow heat transfer with prescribed wall heat flux
Authors: Akins R. G. , Dranoff J. S. 
Published: June 2004

AbstractLaminar‐flow heat transfer in a cylindrical tube was studied experimentally in order to test a recent analytical method of predicting temperature profiles (1). The experimental equipment was designed to measure wall temperatures to better than 0.1°C. and to utilize small radial heat fluxes so as to minimize effects of natural convection.A series of experiments was carried out on five different types of prescribed wall heat flux with water flowing in a vertical tube. The measured wall temperatures in these experiments compared well with those predicted by the theoretical solution. Small deviations which did exist were explained in terms of experimental errors.The agreement found indicates that the analytical method may be safely used in the study of experimental data in such heat transfer and analogous mass transfer problems.
A theoretical and experimental investigation of the effects of horizontal barriers in thermal diffusion columns
Authors: Fleming J. R. , Powers J. E. 
Published: June 2004

AbstractA theoretical and experimental investigation of the effects of horizontal barriers on the separation of binary mixtures attained in thermogravitational thermal diffusion columns was undertaken in an attempt to further the understanding of these effects. The presence of horizontal barriers serves to reduce the internal convective flow and to divide tht column into a number of smaller columns with interconnecting end feeds. Equations developed from such a model serve to predict the effect of the number of barriers, temperature difference, barrier diameter, and other parameters on the steady state and transient behavior of a batch column and on the manner in which bulk flow through the column influences the steady state separation in continuous‐flow columns.Data were taken in both batch and continuous columns to test the theory. Parameters varied experimentally (with an ethanol‐water system) were number of barriers, (N = 0, 2, 4, 8, 16, 50), temperature difference, and diameter of the cylindrical barriers. It was found that the theoretical developments were entirely adequate to explain the observed influence of number of barriers for both types of column operation. The slight dependence of steady state batch separation on temperature difference that was observed is consistent with data of other investigations, and the independence of this type of separation on barrier diameter is in agreement with theoretical predictions. The theoretical predictions with respect to changes in temperature difference and a semitheoretical analysis of the effect of barrier diameter making use of isothermal hydrodynamic determinations proved satisfactory in predicting the influence of changes in these two parameters on both the transient batch and steady state continuous‐flow column operation.
Unsteady state absorption of carbon dioxide by dilute sodium hydroxide solutions
Authors: Rehm T. R. , Moll A. J. , Babb A. L. 
Published: June 2004

AbstractRates of carbon dioxide absorption by 0.01, 0.05, and 0.1 molar sodium hydroxide solutions were measured at 25°C. for exposure times from 1.4 to 21.6 milliseconds with a laminar‐jet technique. Absorption rates were calculated with a model based on one‐dimensional diffusion occurring simultaneously with two consecutive irreversible chemical reactions. The resulting partial differential equations were solved with an IBM‐709 computer. The calculated absorption rates agreed within 5% of the experimental values.
Thermal diffusion of salt solutions in single‐stage cells and in continuous horizontal columns: The system copper sulfate‐cobalt sulfate‐water
Authors: Fisher G. T. , Prados John W. , Bosanquet L. P. 
Published: June 2004

AbstractThe application of thermal diffusion to the separation of a pair of salts in aqueous solution was investigated. Experiments were conducted with the system copper sulfate‐cobalt sulfate‐water with both static, single‐stage cells and continuous, countercurrent flow contactors (or columns) of the horizontal Jury‐Von Halle type which utilizes flow through a porous membrane. Design equations for the continuous columns were developed, based on an idealized representation of the combined hydrodynamic and diffusion problem. Data from the single‐stage experiments were used in conjunction with these equations to predict stage separation factors and transfer unit heights. These mass transfer parameters were measured under various operating conditions on continuous units of two different sizes.The effects of size and operating conditions on the separation factor and transfer unit height were successfully predicted by use of the design equations. The accurate calculation of these quantities directly from single‐stage separation data was less successful, owing to the highly idealized nature of the mathematical model employed.
An engineering study of the rotary drum crystallizer
Authors: Chaty John C. , O'Hern Harold A. 
Published: June 2004

AbstractIn the rotary drum crystallizer, solids are deposited from a molten liquid mixture on the cooled surface of a drum. Rotation of the drum carries the solids from the melt to a scraper blade which removes the crystal deposit in a liquid free, convenient form. The object of this investigation was to obtain data on the separation of binary mixtures over a range of melt temperature, drum coolant temperature, drum rotational rate, concentration of impurity in the liquid, and agitation of the liquid. Four systems were studied: naphthalene‐benzoic acid, beta‐naphthol‐naphthalene,p‐xylene‐m‐xylene, water‐sodium chloride.The experimental results show that separation improved with increasing agitation, increasing coolant temperature, decreasing drum speed, and decreasing liquid impurity. For the naphthalene‐benzoic acid system, the major system studied, the maximum stage efficiency was 96%. The results indicate that the vigor of agitation and the drum coolant temperature are the two most important variables which affect the separation. It was possible to calculate the rate of solid deposition with heat transfer data.The rotary drum crystallizer appears to be an effective device for industrial separation of organic chemicals.
Use of adiabatic experiments for kinetic studies in fixed catalyst beds
Authors: Schmidt J. P. , Mickley H. S. , Grotch S. L. 
Published: June 2004

AbstractA method is presented for using an adiabatic reactor to study the kinetics of reactions of gases on solid catalysts. The method is based on measurement of the steady state axial profile of temperature or composition in a specially designed adiabatic packed bed reactor. Reaction rates are calculated from these measured profiles by graphical differentitation. The method is applicable for multireaction systems and for any type of kinetic behavior.The method was demonstrated by an experimental study of cumene cracking an silica‐alumina catalyst at 420° to 480°C. The measured reaction rates are in satisfactory agreement with results obtained by other investigators who used isothermal reactors. Areas of application of the adiabatic method are suggested.
Turbulent motion and mixing in a pipe
Authors: Lee Jon , Brodkey Robert S. 
Published: June 2004

AbstractTurbulent mixing of a dye solution injected at the center of a pipe was studied by means of a new light probe developed for the measurement of concentration fluctuations were made both along the axial distance and across the pipe. The concentration fluctuations persisted longer at the center‐line region than anywhere else; this suggested the use of the decay of intensity at the center as an upper limit. Approximately 99% of the initial intensity decayed within 7.5 ft. (30 L/d). The concentration spectra along the axial distance indicated that the eddies initially undergo a scalar energy cascade. Because of the huge difference in the kinematic viscosity and molecular diffusivities the concentration spectra extend much farther toward high wave numbers than the velocity spectrum. Apparently a state of imbalance resulted between the supply of small eddies and their dissipation; this was marked by the appearance of a small hump in the spectra. The phenomenological approximations of Corrsin and of Beek and Miller could be used for the practical problem of predicting the decay of the intensity of the concentration fluctuations or mixing in the pipe geometry studied.