bluuebunny/crossref_metadata_2025 huggingface dataset:
Diffusion in a pore of varying cross section
Authors: Petersen E. E.
Published: June 2004

The ratio of the effective to the normal diffusivity of a material diffusing within porous solids is less than unity. In the simple theory the porosity and tortuosity, or labyrinth, factors are used to explain the magnitude of this ratio and to account respectively for the reduced cross‐sectional area and the increased diffusion distance. However, abnormally large values of the tortuosity factor are obtained from experimentally measured effective diffusivities within pelleted or extruded porous solids. This work is concerned with the quantitative effect of periodic pore constrictions on the effective diffusivity. The pore model assumed for this study is a hyperbola of revolution giving a pore constriction at the vertex of the hyperbola. Solutions to the steady state diffusion equation in a pore of this shape were obtained at various values of β, the ratio of the maximum to the minimum cross‐section in the pore. Comparison of the rate of diffusive transport in this pore and an equivalent cylindrical pore indicates that δ, the ratio of the effective to the normal diffusivity, is about 0.33 at β = 25 for large pores. At the same value of β, δ would be smaller for diffusion in the Knudsen region.
The viscosity of acetone‐water solutions up to their normal boiling points
Authors: Howard Katherine S. , McAllister R. A.
Published: June 2004

The viscosity of acetone‐water liquid solutions has been measured over the entire concentration range at temperatures from 20°C. to generally within 1° to 10°C. of the normal boiling point. A capillary suspended‐level viscometer was used, and the authors estimate that the results are accurate to ±0.2%. Both kinematic and absolute viscosities are given, and the results have been extrapolated to the boiling point of the solutions. The calibration of the Cannon‐Ubbelohde viscometer is discussed in detail.
Axial dispersion of mass in flow through fixed beds
Authors: Carberry J. J. , Bretton R. H.
Published: June 2004

The axial dispersion of water flowing through fixed beds was determined by measuring and recording the dispersion of a pulse input of dye at one or two points downstream of the injection site. Dispersion coefficients at various flow rates were obtained in systems of 1/2‐, 1‐, 3‐, and 5‐mm. spheres and 2‐ and 6‐mm. rings each packed in a 1.5‐in. I.D. column. Data were also obtained with 3‐mm. spheres in a 1‐in. I.D. column. Bed length was varied from 6 to 36 in. Void fractions of from 0.365 to 0.645 were represented by the systems studied. One gas system was studied at Reynolds numbers below unity.

The results of the water study indicate that the dispersion coefficient increases linearly with the Reynolds number in the range of Re = 0.5 to 100. Beyond that point the Reynolds number exponent decreases through 0.85 to a value of about 0.25 at a characteristic breakpoint in the region of Re = 350 to 400. Pressure‐drop data secured for the systems studied clearly indicate that the cited breakpoint in dispersion behavior is identical with the well‐known region of flow transition as characterized by the friction‐factor–Reynolds‐number relationship within a given system.

The dispersion values for the 5‐ and 6‐mm. particles, while obeying this Reynolds‐number functionality, are of lower magnitude.

A theory based upon bed‐v⊙id cell‐mixing efficiency is developed, and this efficiency is shown to be directly proportional to the Peclet number, which at the condition of perfect void‐cell mixing should attain a value of about 2.

Anomalous behavior was noted in two respects: (1) the pulse amplitude change between two stations is greater than that predicted by either diffusion or cell‐mixing theory, lending strong support to a bed‐capacitance effect, and (2) short‐bed studies revealed unusually high dispersion coefficients, reflecting short‐circuiting, that is, poor cell‐mixing efficiencies in these shallow beds, presumably owing to entrance effects, yet independent of the mode of pulse injection.

The dispersion of a pulse of air injected into a stream of helium flowing through a gas chromatographic column was briefly investigated. At Re < 1, E was found to be about equal to the calculated molecular diffusivity of this gas system.
Turbulent heat transfer inside tubes and the analogy among heat, mass, and momentum transfer
Authors: Friend W. L. , Metzner A. B.
Published: June 2004

The effect of fluid physical properties on the rates of convective heat transfer (or mass transfer) to Newtonian fluids flowing turbulently inside tubes has been studied extensively but never resolved for a wide range of variables. In the absence of precise experimental data the conflicting predictions of the many semitheoretical approaches developed during the last two decades have served to confuse rather than to clarify the basic question. To extend the range of the available data an experimental heat transfer study of the heretofore undefined region of high Prandtl number was performed. Fluid properties, determined experimentally, represented a variation in Prandtl number from 50 to 600.

For final correlation all the available data for heat transfer with moderate temperature differences except those on liquid metals were considered. The effect of the Prandtl number for the range of the data (NProf 0.50 to 600) was not well represented by any of the generally accepted theories or empirical equations, although a semitheoretical correlation was deduced from the data with Reichardt's general formulation of the analogy between heat and momentum transfer. The resulting equation fits all the available data with a standard deviation of 9.4%. The applicability of the correlation to turbulent mass transfer in tubes is demonstrated for Schmidt numbers up to 3,000.
Surface dynamics of fluidized beds and quality of fluidization
Authors: Rice W. J. , Wilhelm R. H.
Published: June 2004

Solutions of linearized Navier‐Stokes equations have been developed for the motion of arbitrary two‐dimensional waves occurring at any interface between the emulsion phase of a fluidized bed and the particle‐free, fluid phase. In all cases for which the bed particles are denser than the fluidizing fluid the solutions showed that the lower interface of a bed always is unstable and the upper, stable. The quality of fluidization is suggested to be related at least in part to the rate of growth of surface waves, this rate depending upon physical properties of the system and length of the disturbing wave.
Volumetric properties of nonpolar gaseous mixtures
Authors: Prausnitz J. M. , Gunn R. D.
Published: June 2004

Volumetric data of nonpolar gaseous mixtures are analyzed in terms of the theory of corresponding states. Special attention is given to an analysis of the second virial coefficient and to the calculation of pseudocritical constants.

Second virial coefficients are calculated from experimental data for ten binary systems. These coefficients, with those previously published, are correlated by means of a generalized equation involving three parameters for each component: the critical volume, the reduced temperature, and the acentric factor.

Equations are derived for the pseudocritical temperature and pressure of mixtures. These equations are considerably more accurate than those given by Kay's rule. Because of the complexity of the proposed equations for the pseudocritical parameters, a simplified pseudocritical method is presented which is sufficiently accurate for most chemical engineering purposes, especially at reduced temperatures exceeding 1.3.
Kinetics of steady state phase transitions
Authors: Wilde Kenneth A.
Published: June 2004

A fundamental investigation of the departure from equilibrium in steady‐state phase transitions has been made in terms of irreversible thermodynamics and absolute rate theory. The present status of the concept of accommodation coefficients was reviewed and hypotheses were advanced for the reconciliation of opposing viewpoints. Formulas for the magnitude of the departure from equilibrium were derived for single‐ and multicomponent systems. The deviation from equilibrium appeared to be small for ordinary rates of phase change, but interpretation of the available data was hampered by lack of a detailed molecular picture of the phase‐change process.
Extraction of sugar from beets
Authors: Yang H. H. , Brier J. C.
Published: June 2004

This paper presents the results of a previous investigation on the continuous counter‐current extraction of sugar beets (3) and its correlations. The relationship between the continuous diffusion and the simple diffusion is discussed from the standpoint of extraction rate.
Radial porosity variations in packed beds
Authors: Roblee L. H. S. , Baird R. M. , Tierney J. W.
Published: June 2004

The radial variation of void fraction in randomly packed beds of spheres, cylinders, Raschig rings, and Berl saddles was investigated. After packing, the beds were filled with paraffin, which was then allowed to solidify. Slabs were cut from the bed, and annular rings were removed by two different experimental techniques. An analysis of experimental error revealed that reproducibility, for the sample size used, between different parts of the same bed and different beds was quite good.

For highly irregular shapes such as Berl saddles results indicate that the void fraction decreases regularly from one at the wall to the average porosity at about 1 particle radius from the wall. This is in agreement with work of other investigators using irregularly shaped packings; most commercial packings would probably fit in this category.

For regularly shaped particles results are quite different. For spheres and cylinders cycling was observed for more than 2 particle diam. into the bed, the amplitude decreasing as distance from the wall was increased. The maxima and minima were observed at integral multiples of the particle radius. For Raschig rings a hump was observed at about 1/2 particle radius from the wall. The void fraction then decreased to its average value at 1 particle radius and then remained constant.
Flow patterns of liquids in agitated vessels
Authors: Aiba Shuichi
Published: June 2004

In this paper flow patterns of liquids in an agitated vessel of 11 1/2‐in.I.D. were measured with the radioisotope of cobalt as a means of measurement. Flow patterns of representative types of impellers, namely paddle, turbine, and propeller, were studied. Water and glycerine solutions were used as liquids the viscosity of which ranged from 1 to 108 cp. Effects of geometrical factors of agitated systems on flow patterns were investigated, in particular those of baffles.

Experimental results obtained were analyzed, and a curve showing the relation between flow patterns and power consumption by the agitation was made.
Nonequilibrium thermodynamics: A survey
Authors: Denbigh K. G.
Published: June 2004

This paper presents a review of the field of thermodynamics of irreversible processes. The three essential steps in the use of this form of thermodynamics are the calculation of the entropy production, the setting up of the linear phenomenological equations, and the use of the Onsager reciprocal relation. The most important applications are to the transport processes, especially to the coupling phenomena which occur when two or more such processes take place in the same system.
Simplified calculation of chemical equilibria in hydrocarbon systems containing isomers
Authors: Smith Buford D.
Published: June 2004

An improved method is presented for handling isomer groups in the calculation of chemical equilibria in complex hydrocarbon mixtures. The new method reduces the number of simulataneous equations involved and makes practical the rigorous calculation of any hydrocarbon system for which free‐energy data are available, no matter how complex.
Control‐system design for a chemical process by the root‐locus method
Authors: Ellingsen Walter R. , Ceaglske Norman H.
Published: June 2004

This paper illustrates the application of the root‐locus method in the design of a control system for a theoretical stirred‐tank reactor. The merits of control by measuring reactor concentration or temperature were considered at both an unstable and stable steady state reactor condition. The modes of control studied were proportional, proportional‐integral, and proportional‐integral‐rate.
Transitional velocity patterns in a smooth concentric annulus
Authors: Walker J. E. , Rothfus R. R.
Published: June 2004

Profiles of mean local velocities have been experimentally determined in a smooth, concentric, horizontal annulus having a radius ratio of 0.331. The test fluid was water at room temperature flowing steadily at Reynolds numbers in the viscous, transition, and lower turbulent ranges. The transitional profiles, obtained by means of an impact probe, are summarized and discussed. Limits of the transition zone are established, and variation of the radius of maximum velocity with Reynolds number is confirmed.
Simultaneous development of velocity and temperature distributions in a flat duct with uniform wall heating
Authors: Siegel Robert , Sparrow E. M.
Published: June 2004

Laminar forced‐convection heat transfer in a parallel‐plate channel (flat duct) with uniform heat flux at the walls is analyzed. The velocity and temperature distributions, both uniform at the entrance section, develop simultaneously as the fluid flows through the duct. The heat transfer results, obtained for the Prandtl‐number range of 0.01 to 50, include the Nusselt‐number variation along the channel and the wall‐temperature variation corresponding to the prescribed uniform heat flux.
Liquid‐liquid extraction equilibrium data of cobalt nitrate—nickel nitrate—nitric acid solutions
Authors: Scharf E. J. , Geankoplis C. J.
Published: June 2004

Studies of the solvent extraction of cobalt and nickel nitrates from aqueous solution would add to the fundamental knowledge of extraction of metal salts. In experiments performed to determine the extractibility of these metals as nitrates from aqueous solutions by organic solvents, normal butanol was found to be the best solvent and gave equilibrium distribution coefficients K for cobalt or nickel nitrate of about 0.3. The presence of nitric acid tended to decrease these at high metal concentrations.

In mixtures of the two metals the K value of either metal was found to depend on the total metal concentration. Low separation factors of about 1.3 were obtained. Very high K values of over 5 were obtained for the equilibrium extraction of the nitric acid in the presence of the metal nitrates by the n‐butanol an indication of commercial possibilities.
Heat and mass transfer from wall to fluid in packed beds
Authors: Yagi Sakae , Wakao Noriaki
Published: June 2004

Experiments of heat and mass transfer from the tube wall to the fluids flowing through the packed beds were carried out separately. In heat transfer air was used as the fluid, and several kinds of solid particles with low and high thermal conductivities were investigated to determine effective thermal conductivities and wall heat transfer coefficients. In mass transfer the dissolution rate of the coated material on the inner wall of the packed tube to the water stream was measured, and wall mass transfer coefficients were analyzed. It was found that a close similarity exists between the JH and JD factor for the wall coefficients in the turbulent‐flow region.
Interfacial resistance in gas absorption
Authors: Raimondi Pietro , Toor H. L.
Published: June 2004

A laminar jet method for contracting a liquid with a gas for contact times down to 1 msec. has been developed. A jet is formed with a very thin square‐edged orifice to minimize boundary‐layer effects, and the rate of absorption of carbon dioxide into water is found to depend only upon contact time, an indication that the method is self‐consistent.

The rate of absorption of carbon dioxide into pure water is 1 to 4% lower than the theoretical rate for absorption into a jet in rodlike flow the surface of which is instantaneously saturated. This indicates that, at most, interfacial resistance in this system is small and justifies the common assumption of interfacial equilibrium.

Jets with thick boundary layers were formed with other types of orifices, and the absorption rates into these jets were lower than the theoretical value because of the decreased surface velocity. This effect can be easily mistaken for an interfacial resistance.

The presence of a commercial surface‐active agent causes an apparent interfacial resistance which is due at least partly to a hydrodynamic effect.
An improved equation of state for gases
Authors: Martin Joseph J. , Kapoor Rajendra M. , Nevers Noel De
Published: June 2004

Based on properties which are characteristic of all gases, modifications are developed for an equation of state previously proposed in this journal (1). A specific application of the modified equation is made for the PVT data on carbon dioxide, and considerable improvement over the original equation is shown for densities in the neighborhood of 1.4 times the critical density. The new equation differs from the old equation only by the presence of the A5 and C5 terms, these having originally been taken to be zero.
Interfacial resistance in the absorption of oxygen by water
Authors: Chiang S. H. , Toor H. L.
Published: June 2004

Transient absorption rates of oxygen into water have been measured by passing a laminar jet through the pure gas for contact times varying from 0.8 to 11.8 msec. The absorption rate is significantly lower than the theoretical value corresponding to no interfacial resistance, if a diffusivity of 2.20 × 10−5sq. cm./sec. at 22.2°C. is used for comparison. The available evidence indicates that this diffusivity is about correct and that the lowered rate may be caused by an interfacial resistance described by an interfacial transfer coefficient equal to 0.6 cm./sec. This resistance is small enough to be neglected in most gas absorbers.
Factors affecting density transients in a fluidized bed
Authors: Dotson James M.
Published: June 2004

The effects of five operating variables on the uniformity of fluidization in a 4‐in.‐diameter column were determined by a statistically designed experiment. Density fluctuations inside the bed were measured by a capacitance method. Certain parts of the experiment were repeated in a 24‐in.‐diameter column for comparison with the 4‐in.‐column data.

In the 4‐in. column gas velocity had by far the greatest effect on uniformity, with uniformity generally decreasing with an increase in gas velocity. This is consistent with the theory that most gas introduced in excess of the rate for incipient fluidization passes through the bed in the form of various‐sized bubbles. Better uniformity at the lower bed level indicates that bubbles grow in size as they proceed up the column. An entirely different gas‐flow pattern was indicated in the 24‐in. column.
Viscous flow relative to arrays of cylinders
Authors: Happel John
Published: June 2004

The free‐surface model, successfully employed to predict sedimentation, resistance to flow, and viscosity in assemblages of spherical particles, has been extended to the case of flow relative to cylinders. It is shown to be in good agreement with existing data on beds of fibers of various types and flow through bundles of heat‐exchanger tubes for cases where it can reasonably be expected to apply. Close agreement in the dilute range with the only theoretical treatment for flow parallel to a square array of cylinders provides interesting validation of the model.
Liquid‐side mass transfer coefficients in packed towers
Authors: Onda Kakusaburo , Sada Eizô , Murase Yasuhiro
Published: June 2004

The physical absorption of gas by water in a tower packed with Raschig rings has been investigated. The liquid‐side mass transfer coefficient which was separated by dividing the capacity coefficient by the wetted surface area is discussed from the standpoints of the two‐film and penetration theories. A new and simpler dimensionless group is presented which correlates about 90% of the data reported, including the author's own, within an accuracy of ±20%.
Phase equilibria in mixtures of polar and nonpolar compounds: Derived thermodynamic quantities for alcohols and hydrocarbon
Authors: Black Cline
Published: June 2004

The properties of vapor mixtures and liquid solutions which determine phase equilibria are of special importance in separation processes. They include the vapor‐phase imperfections; the liquid‐phase activity coefficents; and the excess heat, entropy, and free energy of mixing.

Correlation of these properties in nonpolar mixtures is relatively simple, but in mixtures of polar and nonpolar compounds the molecular interactions lead to more complex relations. Semiempirical relations reported earlier (3, 4) have been used to calculate the vapor imperfections and to correlate the liquid‐phase activity coefficients.

Temperature variations of the activity coefficients can reflect the true heat and entropy effects in solution if sufficient vapor‐liquid equilibria are available for a careful and consistent treatment. This is illustrated with binary mixtures of benzene and the n‐aliphatic alcohols, methanol to pentanol. The results are compared with calorimetric data available in the literature.

The consistent set of cross‐correlated coefficients provides a basis for calculating both isothermal and isobaric vapor‐liquid equilibria at various conditions for the binaries and for certain ternary and multicomponent mixtures without any additional data.
The phase behavior and solubility relations of the benzene‐water system
Authors: Rebert Charles J. , Kay Webster B.
Published: June 2004

In order to contribute to knowledge of the nature of the phase behavior of partially miscible liquid systems, a study of the benzene‐water system was undertaken. The pressures at liquid‐ and vapor‐phase boundaries of fifteen mixtures of benzene and water were determined within the temperature range of 200 to 357°C. Along with a complete numerical tabulation, these data are presented graphically as pressure‐temperature, pressure‐composition, and temperature‐composition phase diagrams to show the nature of the boundaries.

Up to the three‐phase critical end point, the benzene‐water system develops in a manner usually ascribed to a partially miscible system in which the vapor compositin at a point of univariance lies intermediate to the two liquid compositions. The three‐phase critical end point occurs at 1,364 1b./sq. in. abs. and 268.3°C., and the composition of the critical phase is 25.8 weight % water, with the remaining liquid phase 92.8 weight % water.

The pressure, temperature, and composition of the critical solution end point are deduced as 2,300 1b./sq. in. abs., 306.4°C., and 59 weight % water, respectively. At temperatures between these two critical points the phase behavior is likened to that of a dense gas or fluid dissolved in a liquid. Definite limiting values of temperature and pressure are assignable to this behavior by the extension of the three‐phase curve up to the critical solution end point. This extended curve is not a phase boundary, but the temperature and pressure at a given point on the curve represents in a mixture of fixed composition the limit of mutual solubility of the benzene‐rich fluid phase and the water‐rich phase. At a temperature above or a pressure below the given point the liquid phase begins to vaporize.

Above the critical solution end point the vapor‐liquid phase boundaries are like those of a normal binary mixture.
Multicomponent distillation on a large digital computer: II. Generalization with side‐stream stripping
Authors: Amundson N. R. , Pontinen A. J. , Tierney J. W.
Published: June 2004

The problem of multicomponent distillation is considered for a column with an arbitrary number of feed streams and an arbitrary number of side‐stream withdrawals. The overheads from the side‐stream strippers are admitted to the column, introducing the inert stripping medium into the main column. Provisions are made in the calculations for complete heat balancing, inert injection, and internal reflux cooling. The method of computation is that of a previous paper involving the component‐by‐component technique. Calculations are made on the main column and give first approximations to the side‐stream compositions; stripper calculations are then initiated. An alternating procedure is instituted between the main column and the strippers, the successive iterations continuing until a preassigned accuracy in the desired quantities is reached. An extensive numerical problem is worked.
Formation of gas bubbles at submerged orifices
Authors: Hayes W. B. , Hardy B. W. , Holland C. D.
Published: June 2004

The formation of air bubbles at constant pressure at submerged orifices was investigated for several liquids. The frequency of formation of the bubbles was determined by the use of a stroboscope, and the rate of gas flow was measured with conventional rotameters. Several orifices having diameters ranging from 0.0794 to 0.397 cm. were employed, and the gas flow rate was varied from about 0.1 cc. (at standard conditions)/sec. to about 150 cc./sec. It was found that the formation of bubbles could be correlated with the physical variables of the system by the application of Newton's second law of motion to the bubble at the instant just prior to its release from the orifice.
Diffusion‐controlled chemical reactions
Authors: Toor H. L. , Chiang S. H.
Published: June 2004

Transformation are obtained which reduce the system of differential equations for certain types of diffusion‐controlled reactions to the equation for pure diffusion.

Simple relationships between the diffusion rate with and without reactions are presented for reversible unimolecular reactions, certain types of reversible bimolecular reactions, and irreversible reactions between species with equal diffusivities. It is shown that these relationships are independent of geometry, hydrodynamics, or boundary conditions, and so the mass transfer coefficient in the presence of reactions can be obtained from the coefficient in the absence of reactions without an explicit knowledge of the mass transfer mechanism.

The reaction factor for irreversible reactions with equal diffusivities, obtained by others for specific mass transfer mechanisms, is found to be quite general and essentially independent of the mechanism.

Some data on the absorption of sulfur dioxide in a laminar water jet is considered.
Mechanism of drying thick porous bodies during the falling‐rate period: II. A hygroscopic material
Authors: Bell J. R. , Nissan A. H.
Published: June 2004

A further analysis of the second falling‐rate period in the drying of thick highly porous textile structures is made, this time in the case of drying wool, special attention being paid to the adsorbed water held by the wool in the air‐dry region. As the solid‐to‐void ratio is low, the quantities of adsorbed water are small and have little effect on the general equilibrium. Values of thermal conductivity are calculated for wet wool.
Vinyl chloride from acetylene and hydrogen chloride: Catalytic‐rate studies
Authors: Wesselhoft R. D. , Woods J. M. , Smith J. M.
Published: June 2004

The reaction rate of gaseous acetylene and hydrogen chloride was studied experimentally on a mercuric chloride–activated carbon catalyst at pressures from 1 to 4 atm. and temperatures of 167°, 212°, and 257°F. The measurements were made in a differential reactor packed with mercuric chloride impregnated on activated carbon, the data being taken to obtain the separate effect of the partial pressure of each of the components on the rate.

The results indicated that hydrogen chloride was strongly adsorbed on the catalyst and that vinyl chloride was also adsorbed to a significant extent. A rate equation, which well represented the data, was developed from the following postulates: (a) acetylene is adsorbed on the catalyst on one type of site, (b) hydrogen chloride and vinyl chloride are adsorbed on a different kind of site, (c) the formation of vinyl chloride occurs by reaction of adsorbed acetylene and adsorbed hydrogen chloride, and (d) the rates of adsorption and desorption are fast compared with the formation rate of vinyl chloride.
Thermal conductivity of diatomic gases: Liquid and gaseous states
Authors: Schaefer Charles A. , Thodos George
Published: June 2004

After an extensive literature survey the experimental thermal‐conductivity data for twelve diatomic gases were utilized to produce an accurate and expedient means of predicting values over extensive ranges of temperature and pressure. Plotting values ofk* againstTRon logarithmic coordinates produced similarities pointing to the existence of corresponding states behavior for this family of substances with the exception of hydrogen. Because hydrogen cannot be included in a correlation generalized for the diatomic gases, it has been eliminated from this study. Based on atmospheric pressure data, ratios ofk*/k*Tcproduced a unique relationship with reduced temperature. To include the effect of pressure, residual thermal conductivities were correlated with density for nitrogen and oxygen, the only substances for which high‐pressure data exist. These relationships enabled the determination of the thermal conductivity at the critical point. When the valuekc= 8.55 × 10−5cal./sec. cm. °K. for nitrogen was used, au extensive reduced thermal‐conductivity correlation was constructed against reduced temperature for parameters of constant reduced pressure. This chart, extending to reduced pressures of 100 and to reduced temperatures of 85, is recommended for the diatomic gases in their gaseous and liquid states.

The developed correlation reproduces experimental nitrogen data to within 1.39%. For the other diatomic gases experimental agreement extends from 1.00 to 3.20%. Such agreement indicates that this correlation is more reliable for the diatomic gases than are other generalized plots presented in the literature.
Theory of solvent extraction of phosphoric and hydrochloric acids
Authors: Seaton W. H. , Geankoplis C. J.
Published: June 2004

Mixtures of hydrochloric and phosphoric acids were extracted from aqueous solution by organic solvents in a study to advance the theories of solvent extraction.

Four solvents, t‐amyl alcohol, n‐butanol, cyclohexanol, and 2‐hydroxyethyl, n‐hexyl ether, were found to give high distribution coefficients of 0.1 to 0.5 for both acids. In studies using the ether type of solvent an increase of the pH of the aqueous phase from 0 to 10 reduced the distribution ratio of phosphoric acid by a factor of 1,100.

The substitution of hydriodic acid for hydrochloric caused a 42% increase in the K of phosphoric acid, which could indicate the importance of internal pressure of the additive in extraction. Measurements of activity coefficients of the hydrochloric acid in aqueous solution showed only a 1% increase in its activity coefficient with addition of large amounts of phosphoric acid. This could not be sufficient to cause up to a 40% increase in the distribution coefficient of the hydrochloric acid with the addition of the phosphoric acid.
Solid‐catalyzed reaction in a fluidized bed
Authors: Lewis W. K. , Gilliland E. R. , Glass Werner
Published: June 2004

Results are presented for the solid‐catalyzed hydrogenation of ethylene in fixed and fluidized beds. The effect of gas velocity, bed height, catalyst activity, particle size, and internal baffles on fluidized reactor efficiency are given, and Equations derived from a simplified mathematical model correlate the data.
Void fractions in two‐phase flow
Authors: Isbin H. S. , Rodriguez H. A. , Larson H. C. , Pattie B. D.
Published: June 2004

Void fractions (fraction of the flow cross‐sectional area occupied by the gas phase) have been measured for steam‐water flows in an adiabatic, horizontal test section of 0.484 in. I.D. at 400, 600, 800, and 1,000 1b./sq. in. gauge. A comprehensive survey of void data for two‐phase concurrent flow is included in the paper, and the data, including the Martinelli and homogeneous flow model predictions, are compared. System characteristics, involving one‐ and two‐component flows in horizontal and vertical test sections with and without heat transfer over a range of flow ratios, total flow rates, and pressure, are too complex, and the data available are neither extensive nor precise enough to warrant the generation of over‐all correlations. Use of the void data in correlating two‐phase frictional pressure drops is discussed. A model has been presented for the prediction of critical flows based upon the void data, and calculations have been made for steam‐water critical flows over a range of critical pressures from 15 to 2,000 1b./sq. in. abs.
Performance of a reciprocating‐plate extraction column
Authors: Karr Andrew E.
Published: June 2004

An open type of reciprocating‐plate extraction column was developed, and it is proposed that the scaling up of such a column should be straightforward; that is, the height of an equivalent theoretical stage (H.E.T.S.) and the throughput per unit area should be independent of the diameter of the column.

Plates having 5/8‐in.–diameter holes and 62.8% free space were selected to minimize the resistance to countercurrent flow in the column. With this design low H.E.T.S. values were achieved at throughputs much higher than those reported for other columns. Thus for two systems the present column was shown to require the lowest volume of column to accomplish a given extraction job. Data were obtained in a 3‐in.–diameter column on two systems, methyl isobutyl ketone‐acetic acid‐water and o‐xylene‐acetic acid‐water. Throughputs studied on the first system ranged from 547 to 1,837 gal./hr./sq. ft., and the corresponding minimum H.E.T.S. values achieved were 4.3 and 7.5 in. respectively. For the second system minimum H.E.T.S. values of 7.7 and 9.1 in. were attained at throughputs of 424 and 804 gal./hr./sq. ft. respectively.

Extraction column design procedures are discussed. The fabrication of the reciprocating‐plate column is relatively simple, and this should encourage its use first in pilot‐scale sizes and ultimately in large‐scale columns.
Kinetics of the hydrogenation of ethylene: (On a nickel catalyst)
Authors: Pauls A. C. , Comings E. W. , Smith J. M.
Published: June 2004

A differential type of flow reactor, 0.25‐in. I.D., was used to study the kinetics of the hydrogenation of ethylene on an alumina‐supported nickel catalyst. This is apparently the first investigation made above atmospheric pressures. Data were obtained from 14.7 to 70 1b./sq. in. abs. and feed compositions from 40 to 90 mole % hydrogen. Measurements at temperatures from 30° to 80°C. indicated an apparent activation energy of 11,600 cal./g.‐mole.

It was found that the activity of the catalytic surface was reduced by exposure to ethylene, or mixtures containing an excess of ethylene, owing to the formation of acetylene residues. Pretreatment of the catalyst at temperatures of 170°C. with mixtures of ethylene and hydrogen stabilized the catalyst so that reliable rate data could be obtained.

The rate measurements at 70°C. were correlated by an equation. While the mechanism of the reaction cannot be determined from the data, the rate expression and other kinetic studies suggest a process in which hydrogen is adsorbed on the small fraction of the surface not occupied by acetylenic residues and the reaction takes place between this adsorbed hydrogen and ethylene in the gas phase.
Interfacial turbulence: Hydrodynamic instability and the marangoni effect
Authors: Sternling C. V. , Scriven L. E.
Published: June 2004

The origin of interfacial turbulence, spontaneous agitation of the interface between two unequilibrated liquids, has been explained in terms of classical flow, diffusion, and surface processes. The essence of the explanation is the long‐known though much neglected Marangoni effect, wherein movement in an interface is caused by longitudinal variations of interfacial tension. It is proposed that interfacial turbulence is a manifestation of hydrodynamic instability, which is touched off by ever present, small, random fluctuations about the interface.

A simplified mathematical model has been analyzed in order to detail the mechanism of the “interfacial engine” which supplies the mechanical energy of interfacial turbulence. In its present form the analysis incorporates several drastic simplifications, though ways of removing some of these have been suggested. The groundwork has been laid for the more elaborate analyses that are needed for a decisive test of the theory.

The analysis shows how some systems may be stable with solute transfer in one direction yet unstable with transfer in the opposite direction, a striking result. It also suggests that interfacial turbulence is usually promoted by (1) solute transfer out of the phase of higher viscosity, (2) solute transfer out of the phase in which its diffusivity is lower, (3) large differences in kinematic viscosity and solute diffusivity between the two phases, (4) steep concentration gradients near the interface, (5) interfacial tension highly sensitive to solute concentration, (6) low viscosities and diffusivities in both phases, (7) absence of surface‐active agents, and (8) interfaces of large extent.

That some of these effects have been observed in the laboratory lends credence to the theory.
Heat and mass transfer in spray drying
Authors: Dlouhy Jan , Gauvin W. H.
Published: June 2004

Studies of the evaporation and drying rates in an experimental concurrent spray dryer, 8 in. in diameter and 14 ft. high, are reported for various operating air temperatures. It was found that the total evaporation and drying time could be accurately predicted by employing a step‐by‐step method of calculation. Owing to the probable absence of internal diffusional resistance in the small particles, less than 30 μ, produced in the dryer, no significant falling‐rate period was observed. This was in marked contrast with tray‐drying experiments carried out on the same substance, under similar drying conditions. The results also confirmed that a Nusselt number of 2 can safely be used in spray‐drying heat transfer calculations.
The critical constants of the elements
Authors: Gates David S. , Thodos George
Published: June 2004

The critical temperatures available in the literature for seventeen elements constitute the basis of this study for predicting critical temperatures from normal boiling points. When not available, the normal boiling point can be estimated from vapor‐pressure data. The extension of the vapor‐pressure data beyond the normal boiling point establishes the critical pressure from the estimated critical temperature.

In accordance with this procedure, critical temperatures and pressures have been predicted for thirty‐six elements included in the periodic table from lithium to uranium. These critical constants consitute the core of this study and have been used to calculate both van der Waals' constants. These constants, when plotted against their atomic numbers, produce correlations that may permit the further prediction of van der Waals' constants for other elements.

A simple relationship between the critical volume and the volume van der Waals' constant is found to exist and is presented as a basis for predicting the critical volume of elements.
Effect of a cylindrical boundary on a fixed rigid sphere in a moving viscous fluid
Authors: Fayon A. M. , Happel John
Published: June 2004

In this investigation of the effect of a cylindrical boundary on a spherical particle suspended in a moving viscous fluid the pressure drop due to the motion of fluid past a stationary sphere and the drag on the sphere are independently measured, and the sphere‐ to‐cylinder‐diameter ratios varying from 0.1250 to 0.3125 are studied at different positions of eccentricity. The investigation shows that in the range of Reynolds numbers from 0.1 to 40.0, based on the approach velocity to the sphere and the diameter of the sphere, the pressure drop due to the presence of a sphere and the drag on it can be represented by a semiempirical relationship containing two terms. One term, owing to the effect of the cylindrical boundary, is derived theoretically from the creeping‐motion equations which neglect inertial effects. The second term, owing to the inertial effects, is established from data on the drag coefficient of a sphere in on unbounded medium.
Detonation characteristics of hydrogen‐oxygen mixtures
Authors: Moyle Morton P. , Morrison Richard B. , Churchill Stuart W.
Published: June 2004

Detonation velocities were measured in mixtures of hydrogen and oxygen containing 25 to 75 mole % hydrogen at initial temperatures from 160° to 580°K. and initial pressures from 1/2 to 2 atm. The measurements were made in a number of tubes of different diameter to permit extrapolation to a tube of infinite diameter. Theoretical detonation characteristics were computed for the same range of conditions. The measured and computed velocities are in good agreement except in rich mixtures and at subatmospheric pressures. Schlieren photographs reveal that the detonation wave front is very thin for a stoichiometric mixture but degenerates to a complicated zone of interacting shock waves and turbulent combustion as the percentage of hydrogen is reduced. The detonation velocity is found to depend only slightly on initial temperature and pressure. The computed pressures behind the detonation and reflected waves are roughly proportional to initial pressure and to the reciprocal of the initial temperature.
Studies on heat transfer near wall surface in packed beds
Authors: Yagi Sakae , Kunii Daizo
Published: June 2004

From studies of annular packed beds wherein the heat flows purely radially, the authors obtained the coefficients of heat transfer on the inner tube surface, as well as the mean effective thermal conductivities of bed. The inner and outer diameters of the annular packed bed were 22 and 70 mm. respectively, and the packings shown in Table 1 were used. The wall film coefficients obtained with air flowing axially through the bed were correlated for NReM < 600 by means of Equation (14).

The coefficients of heat transfer for cylindrical packed beds reported previously by other observers were correlated also by Equation (14), with 0.054 used for values of αω in the range NReM < 2,000.

Consideration of Equation (14) in terms of a theoretical model of heat transfer showed that it was reasonable to apply it for the prediction of wall film coefficient, especially for low Reynolds numbers.
Mechanics of particle bounce
Authors: Ranz W. E. , Talandis G. R. , Gutterman Bernard
Published: June 2004

Irregular particles bounce with randomly distributed angles of reflection. There is a certain probability that a particle striking at low angle will bounce at a high angle and be carried far out into the main fluid flow. Bounce phenomena were investigated with respect to bounce of a model particle, limitations on dust collection (back mixing), and energy loss during the flow of suspensions.
Compressibility and vapor pressure of methyl borate
Authors: Griskey Richard G. , Gorgas Walter E. , Canjar Lawrence N.
Published: June 2004

Pressure‐volume‐temperature measurements have been made on methyl borate over the temperature range of 2257deg; to 300°C. and pressures of 30 to 200 atm. in a variable volume P‐V‐T bomb. Vapor‐pressure measurements from 180°C. to the critical point have also been made with the same apparatus. The vapor‐pressure data are presented in the form of the Antoine equation, and the P‐V‐T data together with the vapor‐pressure data have been fitted to the Benedict‐Webb‐Rubin equation of state.
The motion of two spheres following each other in a viscous fluid
Authors: Happel John , Pfeffer Robert
Published: June 2004

The purpose of this investigation was to determine the interaction effect of one spherical particle upon another when both are falling in a viscous fluid. The velocities of two identical spheres, falling along the axis of a cylinder in a direction parallel to their line of centers, were measured experimentally as a function of the center‐to‐center distance between them at very low Reynolds numbers. The experimental results compared very well with theoretical studies found in the literature which predicted that two spheres will fall faster than one sphere.

At Reynolds numbers greater than 0.25 the influence of inertial effects were studied for one end two spheres. The experimental results qualitatively confirmed the Oseen equations. A definite attraction between two spheres falling one above the other was observed; the inertial forces acted to slow down the lower sphere without affecting the upper one.
Mass transfer inside drops
Authors: Johnson A. I. , Hamielec A. E.
Published: June 2004

The transfer rates of n‐butanol, cyclohexanol, and ethyl acetate into water drops have been measured for circulating and oscillating drops.

Methods of allowing for the end‐effect transfer have been extended and measured values compared with predictions of a model.

Various mechanisms for transfer inside drops have been examined in terms of a correlation factor.
Compressions of liquids. II. Critical evaluation of new n‐alkane data: n‐Heptane to n‐tetracontane
Authors: Doolittle Arthur K. , Doolittle Dortha B.
Published: June 2004

New measurements of the volumes of liquid n‐alkanes of 7, 9, 11, 13, 17, 20, 30, and 40 carbon atoms over a range of temperatures from 20° to 300°C. and pressures from 0 to 4,000 kg./sq. cm. have been made. These volume measurements are here reduced to compressions (vol)/(vol°T), and the accuracy of the measurements has been determined. Analysis of the data for n‐heptane and n‐eicosane shows that the order of accuracy of the compressions of each of these compounds appears to be approximately 3 parts in 10,000. Evaluation of random multiple measurements on the remaining six compounds indicates that their over‐all accuracy is likewise of this same order.
Compressions of liquids. III. Temperature and molecular weight dependence of the Hudleston parameters for the n‐alkanes
Authors: Doolittle Arthur K. , Doolittle Dortha B.
Published: June 2004

General equations for the temperature dependence of the parameters of the Hudleston equation are given which were deduced from a study of n‐alkane compression data. Empirical expressions for the molecular‐weight dependence of the constants of these equations are likewise given which are applicable only to n‐alkanes. By use of these relations in the Hudleston equation the compressions of the family of liquid n‐alkanes over ranges of T, P, and m were calculated on an IBM‐650 computer. The over‐all standard percentage error (SPE) of the computer calculations for n‐alkanes of 7 to 20 carbons up to temperatures not exceeding their normal boiling points was 0.10%. The over‐all SPE for n‐alkanes of 7 to 40 carbons up to temperatures substantially above their normal boiling points (but not exceeding 300°C.) was 0.21%.
Temperature measurements in a spherical field: Transfer coefficients and corrections for thermocouples in boundary flows
Authors: Short W. W. , Sage B. H.
Published: June 2004

A study was made of the deviation between the temperature of thermocouple junctions and the temperature of the fluid surrounding them which arises as a result of conduction along the thermocouple leads. Measurements around a 1/2‐in. heated sphere in the plane of the equator normal to an air stream having a velocity of 16 ft./sec. were made with a 0.001‐in.‐diam. thermocouple of platinum and platinum rhodium. Air temperatures in the boundary flows of the sphere were predicted from the indications of the thermocouple. The method of prediction employed also determined the heat transfer coefficients for the thermocouple wire in the boundary layer. These local heat transfer coefficients are lower than those observed in a uniform stream having a velocity equal to the estimated local velocity in the boundary layer.