bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phase relations of binary systems that form azeotropes: I. The ammonia–n‐Butane system
Authors: Kay Webster B. , Fisch Herbert A. 
Published: June 2004

AbstractBinary systems that form azeotropes in the critical region of the system show a wide variation in their phase behavior. As part of an investigation of the factors responsible for this variation, the P‐V‐T‐x relations of the ammonia‐n‐butane system were determined at the liquid‐vapor phase boundaries from near room temperature to the highest temperature and pressure at which the liquid and vapor coexist. Ammonia and n‐butane form an azeotrope whose composition varies from 81.7 mole % ammonia at 300 1b./sq. in. to 86.3 mole % at 1295 1b./sq. in. The critical locus possesses a minimum temperature point similar to other binary systems that form azeotropes in the critical region. The experimental results support the hypothesis that binary systems that form azetropes exhibit a characteristic pattern of P‐T‐x relations in the critical region that is distinctively different from systems that do not form azeotropes.
Diffusion in a pore of varying cross section
Authors: Petersen E. E. 
Published: June 2004

AbstractThe 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

AbstractThe 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

AbstractThe 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

AbstractThe 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

AbstractSolutions 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

AbstractVolumetric 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

AbstractA 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.
Radial porosity variations in packed beds
Authors: Roblee L. H. S. , Baird R. M. , Tierney J. W. 
Published: June 2004

AbstractThe 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

AbstractIn 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

AbstractThis 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

AbstractAn 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

AbstractThis 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

AbstractProfiles 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

AbstractLaminar 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

AbstractStudies 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

AbstractExperiments 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

AbstractA 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

AbstractBased 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

AbstractTransient 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

AbstractThe 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

AbstractThe 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

AbstractThe 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

AbstractThe 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.