bluuebunny/crossref_metadata_2025_split huggingface dataset:
Temperatures and partial pressures at the surfaces of catalyst particles
Authors: Yoshida Fumitake , Ramaswami D. , Hougen O. A. 
Published: June 2004

AbstractNumerical and graphical methods are presented for estimating the temperatures and partial pressures at the surfaces of catalyst particles for gaseous reactions in flow systems. The errors resulting in the interpretation of catalytic reaction‐rate data, where surface conditions are assumed to be those of the ambient gas stream, are presented. A numerical method of evaluating the reaction model with nonisothermal surface conditions is indicated.
Kinetics of particle growth in a fluidized calciner
Authors: Lee B. S. , Chu Ju Chin , Jonke A. A. , Lawroski Stephen 
Published: June 2004

AbstractThis study of the factors underlying the mechanisms of particle growth in a fluidized calciner was conducted in a 3‐in. diameter column. In such a calciner radioactive waste liquor from nuclear fuel reprocessing can be converted to a granular solid for disposal. To simulate the octual waste, aluminum oxide as bed material and aqueous aluminum nitrate solution as feed were used. Particle growth was traced through the addition of radiactive seeds. The effects on the growth rate of operating variables and physical properties of the feed were investigated. Statistical analysis of the data substantiated the proposed growth mechanism, and the resulting growth coefficient was correlated with the variables studied.
Mass transfer in dilute turbulent and non‐turbulent systems with rapid irreversible reactions and equal diffusivities
Authors: Toor H. L. 
Published: June 2004

AbstractStudies of mass transfer with rapid, homogeneous, irreversible reactions between dilute species with equal difusivities are carried out with a device which reduces the system of mass transfer‐reaction equations to the equations for mass transfer in the absence of reaction.A relationship which gives the rate of transfer into stagnant, laminar, or turbulent reacting systems is developed. Under some conditions the reaction increases the transfer rates by a constant factor, while under other conditions the reaction increases the individual or over‐all mass transfer coefficients by a constant factor.Calculations of concentration profiles, conversion, etc. are carried out for the Graetz problem with a homogeneous reaction between a dilute species in the fluid and a dilute species diffusing from the tube wall. Reaction completion times for various stagnant elements in infinite media are given.Although the flux into a turbulent reacting fluid is related to the time average behavior in the absence of reaction, the time average concentrations depend also upon the relative intensity of the concentration fluctuations in the absence of reaction. This latter dependence is obtained from a relationship of Hawthorne, et al.Surfaces on which the time average composition is stoichiometric and the reactant concentrations are proportional to the relative intensity of the concentration fluctuations in the absence of reaction are obtained for turbulent flow in a tube with a homogeneous reaction between the fluid and wall. Distances for almost complete reaction are estimated.The time average conversion is related to the accomplished mixing for the case in which two dilute reactants are turbulently mixed. In a uniform, stoichiometric mixture the fractional conversion equals the accomplished mixing. Calculations are carried out for uniform, nonstoichiometric mixtures.
Mass transfer to particles: Part I. Suspended in agitated tanks
Authors: Harriott Peter 
Published: June 2004

AbstractMass transfer coefficients were measured for particles suspended in agitated, baffled tanks. The coefficients for a given particle size and a given fluid vary with the 0.10 to 0.15 power of the power dissipated per unit volume. The coefficients, which cover a one hundred fold range, are about 1.5 to 8 times those predicted from the correlations for fixed particles if the terminal vilocity is used to calculate the particle Reynolds number. The measured effects of particle diameter, diffusivity, viscosity, and density difference cannot be described by a simple expenential equation or by previous empirical correlations. The effects of these variables can be explained by using a slip‐velocity theory combined with a modified penetration theory.
An experimental study of liquid‐phase turbulent diffusion: Part I. Fluid mechanical data
Authors: Sparks Robert E. , Hoelscher H. E. 
Published: June 2004

AbstractResults from an investigation of the fully developed turbulent wake of a circular cylinder are presented. The study was conducted in the liquid phase, in the controlled flow field of a water tunnel. A technique was developed for measuring the intensity of turbulence in water. The decay of turbulence intensity downstream from a series of fine‐mesh wire screens was measured and compared with aerodynamic decay laws. Profiles of the turbulence intensity in the cylinder wake were also obtained. This paper is Part I of a study of liquid phase turbulent mass transfer in the wake of a cylinder. The mass transfer results are reported in Part II.
Gas absorption accompanied by chemical reaction: A study of the absorption of carbon dioxide in aqueous solutions of monoethanolamine
Authors: Emmert R. E. , Pigford R. L. 
Published: June 2004

AbstractExperiments were conducted on the absorption of carbon dioxide in aqueous solutions of monoethanolamine in a very short wetted‐wall column.When the absorption was effected from pure carbon dioxide streams, the results conformed to a theoretical relation for absorption combined with very fast second‐order reaction. This is in accordance with expectations based on the probable mechanism and rate of the reaction. The data indicate that there is no appreciable effect of nonequilibrium at the interface for this particular reaction system over the range of exposure times studied.When mixed gas streams were used, it was necessary to resort to empiricism to correlate the data, although the correlating expression arose from theoretical considerations.
Kinetics of the catalytic dehydration of primary alcohols
Authors: Miller Donald N. , Kirk Robert S. 
Published: June 2004

AbstractThe catalytic dehydrations of n‐butanol, n‐propanol, and ethanol to produce water and the respective olefins were studied for the temperature range 400° to 700°F. and over the pressure range 1 atm. to 100 lb./sq. in. gauge. Silica‐alumina catalyst in bead form was used. Dehydration rates were found to be consistent with a single‐site surface reaction‐controlled mechanism in which was superimposed a mass transfer effect internal to the catalyst pellets. Rate constants for the three reactions are presented. The significances of their relative values and their temperature and pressure dependencies are discussed.
Experimental determination of critical temperatures and pressures of mixtures: The methane‐ethane‐n‐butane system
Authors: Forman J. Charles , Thodos George 
Published: June 2004

AbstractAn experimental unit has been designed and constructed for the study of critical phenomena in multicomponent systems. This unit has been built to utilize a new visual PV̇T cell capable of operating at temperatures up to 300°F. and pressures to 10,000 lb./sq. in. abs. This cell is of the liquid piston type with mercury as the pressurizing fluid and affords unobstructed visual observation of its contents. The dependability of the unit has been tested on two mixtures of ethane and n‐butane. Phase equilibria data were obtained, which in turn were used to establish the critical temperture and pressure.Critical temperatures and pressures have been determined for six different compositions of the methane‐ethane‐n‐butane system. These mixtures consisted of two series, each of three compositions differing only in methane content. The data obtained from them, in conjunction with previously reported critical values for the binaries of this system, have been utilized to generate the complete critical locus for the ternary system. The results for the six mixtures of this study have been compared with critical values predicted by methods available in the literature.
Thermal conductivity of gas mixtures
Authors: Cheung Henry , Bromley Leroy A. , Wilke C. R. 
Published: June 2004

AbstractThermal conductivities of ten gases and selected binary and ternary mixtures of them were measured in a concentric silver cylinder cell over the temperature range from 100° to 540°C. The gases were helium, argon, nitrogen, oxygen, carbon dioxide, methyl ether, and methyl formate.Correlations based upon empirical equations derived from kinetic theory have been developed for the thermal conductivity of gas mixtures. For mixtures of polyatomic molecules the energy transport is considered in two parts, that is one portion transferred by collision and the other by diffusion. When compared with the experimental data for 226 binary mixtures over temperatures from 0° to 774°C., the conductivity equation proposed in this work shows an average deviation of 2.1%.
Axial solid distribution in gas‐solid fluidized beds
Authors: Fan Liang‐Tseng , Lee Chau Jen , Bailie Richard C. 
Published: June 2004

AbstractΓ‐ray attenuation method was applied to determine the axial fluidizing bulk density profile for an air‐solid aggregative fluidized bed. Except for beds fluidized at very high air velocities two distinct density zones were noted. The density of the bed in the lower portion of the column was relatively constant for a particular set of operating conditions and did not vary with bed height. The density in the top portion of the bed fell rapidly with bed height.The average density of the lower zone was correlated as a function of the operating variables. The density in the top zone was represented by a one‐tail normal distribution curve. A somewhat better correlation was obtained by a two‐parameter equation at high air velocities. The effects of operational variables, such as air velocity, static bed height, particle size, and particle‐size distribution on these correlations were investigated.Friction‐factor correlations based on two different definitions of bed height were also obtained.
Laminar and turbulent flow of unstable liquid‐liquid emulsions
Authors: Cengel J. A. , Faruqui A. A. , Finnigan J. W. , Wright C. H. , Kundsen J. G. 
Published: June 2004

AbstractLiquid‐liquid dispersions containing various volume fractions of a petroleum solvent dispersed in water have been studied in laminar and turbulent flow conditions. If one assumes that the dispersion behaves as a single‐phase fluid, measured friction factors may be used to calculate an effective viscosity of the mixture.In laminar flow, viscosities were found to be a function of capillary diameter, possibly due of the formation of a thin film of continous phase adjacent to the capillary wall. The thickness of this film was determined to be of the order of 10 to 25 μ, which is probably of the order of the average size of the droplets.Up to 20% solvent, the relative fluidity (or viscosity) of the dispersions was the same in laminar, vertical turbulent, and horizontal turbulent flow. In the laminar flow case viscosity decreased somewhat with flow rate and became essentially constant at a Reynolds number of about 1,000.In vertical turbulent flow all dispersions behaved as Newtonian fluids, and a single curve (Figure 6) is presented to predict fluidities. The 35 and 50% dispersions in horizontal flow exhibited non‐Newtonian characteristics and had effective fluidities considerably less than the same dispersion in vertical flow but agreed with the horizontal turbulent flow results of Baron, et al. The apparent non‐Newtonian behavior could be due to phase separation in the horizontal tube.Corrected laminar flow fluidities for dispersions with 35 and 50% solvent deviated from the vertical turbulent flow results. Reasons for this are unexplained. In laminar flow also, tube orientation affected the viscosity of the 50% dispersion.
Coalescence and entrainment: Phenomena on sieve trays
Authors: Teller A. J. , Rood R. E. 
Published: June 2004

AbstractEvaluation was made of the effect of hole spacing for 3/16‐in. diameter perforations on a sieve tray, on the magnitude and size distribution of entrainment. The study utilized high‐speed photography and entrainment measurements. The magnitude and average particle size of entrainment appears to be related to the degree of bubble coalescence in the liquid continuous phase and increases rapidly with decrease in hole spacing. Bubble bursts do not contribute significantly to entrainment in multiple perforation geometry; the major contribution occurs from shear of the liquid wall by vapor flumes.
Prediction of vapor‐liquid equilibrium for polar‐nonpolar binary systems
Authors: Finch R. N. , Van Winkle Matthew 
Published: June 2004

AbstractThis paper presents a method of calculating the van Laar constants for binary vapor‐liquid systems. The basis of the method is the van Arkel modification of the van Laar (Scatchard‐Hildebrand) equations which utilize the concept of internal pressure. A generalized method of predicting the apparent internal pressure was developed and described. The experimental van Laar constants and those calculated by the proposed method are compared for twelve polar‐nonpolar binary systems.
The laminar‐turbulent transition in nonisothermal flow of pseudoplastic fluids in tubes
Authors: Hanks Richard W. , Christiansen E. B. 
Published: June 2004

AbstractRyan and Johnson's treatment of the transition from laminar to turbulent flow is extended to include the heated flow of pseudoplastic liquids in smooth tubes. A limitation is pointed out for the case of Bingham plastic fluids.The theoretical results of the present investigation are compared with experimental data obtained for a large number of pseudoplastic fluids having widely variant rheological properties. It is found that the theoretically predicted flow rates corresponding to the inception of turbulence agree with the observed values to within ±6.7%. The theoretical critical wall shear stresses agree within ±3.87% with experiment.
Prediction of vapor‐liquid equilibria from the corresponding states principle
Authors: Leland Thomas W. , Chappelear Patsy S. , Gamson Bernard W. 
Published: June 2004

AbstractA new ideal K value is defined which does not depend on the Lewis and Randall ideal solution rule but is derived only from composition dependent pseudo criticals and the corresponding states principle. Properties of the liquid and vapor mixtures are evaluated from either experimentally measured properties of closely related pure substances or from generalized tables of thermodynamic properties. A derivation of an improved pseudocritical expression applicable to liquids which may be approximated by simple spherical molecules is presented. The derivation illustrates the assumptions involved and points the way for a possible extension of the technique to more complex molecules.There are some advantages to this approach. It does not require the troublesome extrapolation of liquid properties into regions where no liquid can exist, a fact which is characteristic of K value calculations from the ideal solution rule. It is especially useful for systems in which an equation of state is not available for all of the components present. It avoids the difficulties in defining combination rules for complicated equations of state. Even for systems including very complex or moderately polar molecules it provides a base for subsequent empirical modification. This base follows the correct isotherm of In K vs. In P up to the actual critical of the system without the difficulties associated with defining a convergence pressure or evaluating the extremely large activity coefficient corrections to the ideal solution rule in the critical region. For mixtures of simple molecules the calculated ideal K value is within about 10% of the experimental value in both the low pressure and in the critical region. The entire calculation may be expressed completely analytically for use on a digital computer and may be coupled with an equilibrium flash calculation so that the ideal K values may be determined from a given overall composition, temperature, and pressure.
A study of consecutive competitive reaction systems
Authors: Friedman M. H. , White R. R. 
Published: June 2004

AbstractExperimental kinetic data are most conveniently correlated by the integrated form of the differential rate equations which the reactions are presumed to obey. A new method of obtaining an approximate integral solution of the differential equations is described and applied to a set of three consecutive competitive reactions.The approximate integral solution is used to correlate experimental data on systems whose stoichiometry would indicate a consecutivecompetitive mechanism. The compositions of the reaction mixes are predicted with a standard error of estimate of less than 4% of the original concentration of the initiating reactant, in most cases less than 2%. The estimates of the rate constants, found by fitting the approximate solution to the data, are within experimental error of the values obtained by differentiation of the published results.
A diffusion model for rinsing
Authors: Tallmadge John A. , Buffham Bryan A. , Barbolini Robert R. 
Published: June 2004

AbstractThe removal, by immersion in water, of solute from a solution adhering to a 14.7‐cm. wide flat plate has been experimentally investigated at about 80°F. over a 3.5 to 1,000 sec. range of contact time. Diffusivity was varied over a sixfold range (from 0.5 to 3.0 by 10−5 sq.cm./sec.) by the use of two dilute solutions, pontamine blue dye and 0.09 N nitric acid. Equations relating the effects of film thickness, contact time, and diffusivity on the mass fraction of solute which was not removed during rinsing were developed from a diffusion model, under the assumption that the adhering solution was present throughout as a stagnant film of uniform thickness.The experimentally determined effects of time and diffusivity agreed with those indicated by the idealized model. The agreement of these effects and the magnitude of unremoved solute gave strong indication that diffusion may be considered the controlling mechanism. The experimental dip and rinse method used offers potential as a technique for studying natural convection at transient conditions in the region where diffusion is also important, because it offers the advantage of allowing independent selection of initial fluid densities.
Heat transfer in the nitrogen dioxide‐nitrogen tetroxide system
Authors: Furgason R. R. , Smith J. M. 
Published: June 2004

AbstractLocal heat transfer coefficients were carefully measured for the nitrogen dioxide‐nitrogen tetroxide system in well‐developed turbulent flow in an electrically heated, 0.194‐in. I.D. tube. The average probable error determined from reproducibility tests was less than 2%.The modification of the Deissler analogy presented earlier (8) was found to predict coefficients which agreed well (0 to 19% deviation) with the observed results. Some of this deviation may be due to uncertainties in the viscosity data. Brokaw's viscosity information (1) gives results that were higher than the experimental values, but that of Thievon et al. (11) would have given low values.The data were also compared with a simpler Colburn type of analogy in which a heat transfer coefficient based upon enthalpy was employed. The deviations here were larger.
Surface effects in a pulsed, packed column
Authors: Jackson M. L. , Holman K. L. , Grove D. B. 
Published: June 2004

AbstractMass transfer rates and flooding limits are basic to the use of packed columns for liquid‐liquid extraction. The input of pulsing energy increases transfer rates and promotes counterflow of the two phases. The wetting characteristics of the packing influence performance.The toluene‐benzoic acid‐water system was used to observe the performance of a 2‐in. diam. column containing ceramic (hydrophilic) rings, polyethylene (hydrophobic) rings, or a sieve‐plate cartridge. The packed columns showed lower flooding limits than the plate column, but polyethylene packing gave highest transfer rates and capacities. The pulsing energy input was much lower for the plastic packing to effect a higher transfer rate.Flooding limits for the pulsed, packed columns were lower than for packed columns which were not pulsed. Columns packed with rings so that the ratio of diameter to packing size was 4:1 gave higher flooding limits and better performance than a ratio of 8:1. The use of the two types of packing in alternating bands resulted in a performance intermediate between that of each packing employed separately, and no advantage was indicated in reference to flooding limits or transfer rates.
Reaction kinetics in the absorption of chlorine into aqueous media
Authors: Spalding Charles W. 
Published: June 2004

AbstractIt was established that chlorine reacts with both water and hydroxyl ions. At a short reaction time when the pH was less than 3 the reversible reaction of chlorine and water controlled the absorption rate. From pH 3 to 10.5 the forward reaction predominated and yielded an apparent first‐order rate constant of 20.9 sec.−1 at 25°C. Between pH 10.5 and 12.5 the reaction of chlorine with hydroxyl ions occurred simultaneously with the chlorine‐water reaction. Above pH 12.5 the second‐order reaction between chlorine and hydroxyl ions became controlling and the reaction‐rate constant was evaluated to be in the order of 106 liters/(mole)(sec.) at 25°C.These ionic reactions of chlorine were further interpreted through the collision and transition state theories. Certain important quantities with regard to the reaction characteristics were derived from the experimental data.
Kihara parameters and second virial coefficients for cryogenic fluids and their mixtures
Authors: Prausnitz J. M. , Myers A. L. 
Published: June 2004

AbstractThe volumetric properties of sixteen fluids of interest in cryogenic engineering have been used to calculate second virial coefficients over as large a temperature range as possible. These coefficients were then fitted to theoretical expressions based on the Kihara potential function. For helium, hydrogen, and neon quantum corrections were applied. For nitrogen, carbon dioxide, and acetylene corrections for quadrupole interactions were made. It was found that the theoretical expressions give an extremely good fit of all reliable experimental datu. The theoretical expressions may therefore be used with confidence to predict volumetric behavior at very low temperatures where data are frequently unavailable.With the aid of semiempirical mixing rules the theoretical expressions may be used to predict second virial coefficients for mixtures. Agreement with the very limited amount of experimental mixture data is satisfactory. Finally it is shown that calculations based on the Kihara potential may be employed to make useful predictions of phase equilibria such as the solubility of a solid in a compressed gas.