bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heat transfer and fluid dynamics in mercury‐water spray columns
Authors: Pierce R. D. , Dwyer O. E. , Martin J. J. 
Published: June 2004

AbstractHeat transfer and fluid dynamics were studied in columns in which hot mercury was sprayed into a rising stream of water. Volumetric and area heat transfer coefficients are presented which were found to be lower than those reported for heat transfer from fixed spheres.It was observed that considerable water bypassed the stream of drops, while some surrounding the drops flowed downward. This behavior resulted in water temperatures at the base of the column which were considerably higher than the inlet water temperatures. Consequently the outlet mercury temperature did not approach the inlet water temperature as a limit. The very unconventional flow pattern of the water was unexpected and is believed to be an important factor in spray‐column heat transfer and mass transfer kinetics.
Effective diffusivity of packed bed
Authors: Kimura M. , Ueda K. , Ofuka T. 
Published: June 2004

AbstractFrom time to time, A.I.Ch.E. Journal presents translations of certain technical articles written by our Japanese colleagues in their own language. These translations are made by Kenzi Etani, who received his B.S. in chemical engineering in 1953 at the Tokyo Institute of Technology and his M.S. in 1955 at M.I.T. He is associated with Stone & Webster and is an associate member of American Institute of Chemical Engineers. He is also a member of the Society of Chemical Engineers, Japan, and the Japan Oil Chemists' Society. His offer to help break down the language barrier is acknowledged.Abstracts, notation, literature cited, tables, and figure captions not published here appear in English in the original paper. No figure will be reproduced in these translations.The following article was published in Chemical Engineering (Japan), 21, pages 17–25 (1957).
A Computer study of a free‐radical mechanism of ethane pyrolysis
Authors: Snow R. H. , Peck R. E. , Von Fredersdorff C. G. 
Published: June 2004

AbstractThe pyrolysis of ethane (including the equilibrium behavior and the tendency to form secondary products) has been reproduced by calculations based on a reaction mechanism which includes the reverse of the chain propagating reactions as well as other hitherto neglected elementary reactions. Reverse reactions are important even at low conversion (1%); hence previous investigations of initial reaction rate have doubtful fundamental significance. Values of rate constants used in the calculations were taken mostly from the literature. Consideration was limited to reactions of methyl, ethyl, and hydrogen free radicals with ethane and its primary pyrolysis products. The results can be incorporated into reactor performance calculations to replace empirical reaction rate correlations and thus widen the range of conditions over which the calculations are reliable.
Initiation of the homogeneous n‐butane oxidation
Authors: Skrivan J. F. , Hoelscher H. E. 
Published: June 2004

AbstractInitiation of the oxidation of hydrocarbons, an important part of many flame systems' remains largely unsolved. This paper reports a study of the oxidation of butane under conditions that yield information on the homogeneous initiation reactions.A sequential reaction mechanism is proposed involving activation of an oxygen molecule followed by attack on a butane. This leads to rate equations which accurately describe the observed butane decomposition rates. Activation energies have been calculated from experimental data with this equation and are found to check values obtained from the literature and from theoretical considerations.The tentative initiation mechanism is used to explain the existence of three classes of products in the exit gases: hydrocarbons other than butene, butene, and oxygenated products.Under some operating conditions periodic cool flame phenomena are observed, and their effect on the course of the reaction has been explained.
Ion exchange kinetics for systems of nonlinear equilibrium relationships
Authors: Tien Chi , Thodos George 
Published: June 2004

AbstractMathematical relationships based on material balance and rate equations have been derived for the study of ion exchange kinetics in a fixed‐bed operation. Numerical techniques for the solution of the systems possessing equilibrium relationships of the Freundlich‐adsorption isotherm type have been developed, and numerical results have been obtained with the use of a digital computer. The resulting numerical solutions have been found to be dependent on parameters involving time, position, and the relative resistances of the liquid and resion phases. The numerical solutions are presented in both tabular and graphical forms.
Studies of the cation exchange system Fe+++‐H+: I. Equilibrium studies
Authors: Vasishth R. C. , David M. M. 
Published: June 2004

AbstractEquilibrium data are presented for the exchange of Fe+++ and H+ on a sulfonated polystyrene exchanger. The data cover solution concentrations from 0.05 N to 2 N in total cation for solutions having either nitrate or perchlorate ion as the common anion. The nitrate system shows irregular behavior because of complex ion formation, but for composition where such behavior is absent the equilibrium data can be correlated by equations based on the law of mass action. Equilibrium compositions for the perchlorate system can be correlated over the entire range studied by a single equation based on the law of mass action. Methods based on the law of mass action are presented for correlating or predicting equilibrium compositions for both systems.
Studies of the cation exchange system Fe+++−H+: II. Rate studies in concentrated solutions
Authors: Vasishth R. C. , David M. M. 
Published: June 2004

AbstractFixed‐bed kinetic studies were made for Fe+++ — H+ exchange, with perchlorate as the anion, covering concentrations from 0.5 N to 2.0 N in total cation, flow rates of 5 ml./min. sq. cm. to 45 ml./min. sq. cm. bed depth of 25 to 60 cm., and average resin particle diameters of 0.28 and 0.56 mm. The results are correlated on the assumption of internal diffusion as the rate‐controlling step and an essentially irreversible equilibrium.
Fluid dynamics and diffusion calculations for laminar liquid jets
Authors: Scriven L. E. , Pigford R. L. 
Published: June 2004

AbstractIn connection with a study of the mechanism of gas absorption the problem arose of predicting absorption rates into laminar liquid jets. A solution to the problem is presented in this paper, which provides an example of the application of fluid dynamics to the analysis of mass transfer in a complex flow system.The water jets considered here issued from circular nozzles of about 1.5‐mm diameter, flowed intact downward through an atmosphere of solute gas at average velocities of from 75 to 550 cm./sec. over distances of 1 to 15 cm., and were collected in a receiver slightly larger in diameter than the nozzles. Equations describing the liquid flow near the jet surface are deduced from measurements of jet diameter and analogy to related flow situations. When one uses these equations, absorption rates are predicted from unsteady state diffusion theory with the assumption of interfacial equilibrium. The predicted rates for carbon dioxide at 25°C are in close agreement with experimental determinations over the observed range of contact time of the liquid with gas, namely 0.003 to 0.04 sec.
Film boiling of Helium I and other liquefied gases on single wires
Authors: Frederking T. H. K. 
Published: June 2004

AbstractHeat transfer coefficients have been obtained for natural‐convection film boiling of helium I on single wires with a diameter ranging from 5 to 50 μ. The measurements covered temperature differences of 30° to 1,000 °K. between the heating surface and the saturated liquid under atmospheric pressure. The results are correlated in dimensionless from (Nusselt number vs. the product of the Grashof and Prandtl numbers) and compared with data for nitrogen and measurements of other investigators on film boiling of liquefied gases.
Evaporation rates of liquids to flowing gas streams
Authors: Severson D. E. , Madden A. J. , Piret Edgar L. 
Published: June 2004

AbstractThe influence of high concentration gradients and high evaporative velocities on rates of mass transfer was studied by evaporating liquids into low‐speed inert gas streams at pressures approaching the vapor pressure of the liquids.Inert gas concentration in some experiments changed nearly fivefold across the boundary layer. The velocity normal to the surface (owing to evaporation), usually neglected in comparison with main‐stream velocity, varied from 0.038 to 19 times the main‐stream velocity.The data for air‐water, air‐carbon tetrachloride, air‐chlorobenzene, and helium‐chlorobenzene systems were represented within experimental error over the Graetz number range of 0.1 to 1,800 by the flat‐duct equations of Butler and Plewes (2) and also by the usual dimensionless plots.
Expansion and contraction of an air‐water mixture in vertical flow
Authors: Petrick Michael , Swanson Bernet S. 
Published: June 2004

AbstractAn experimental two‐phase flow study was made on an air‐water system at atmospheric pressure to obtain information on the effect of expansion and contraction of flow area on the relative velocity of the two phases. The data show that the relative velocity and hence the mean void fraction of the air‐water mixture changed following either an expansion or contraction; however the magnitude of the change was not great and could be predicted by a semitheoretical equation. The air‐water data are also compared with data taken from a steam‐water system at 150 to 600 lb./sq. in. In addition, a photographic study was made of the transition zone, and phase distributions were obtained by the use of a radiation attenuation traversing technique.
Vaporization of superheated drops in liquids
Authors: Moore G. R. 
Published: June 2004

AbstractThe work reported in this paper is an outgrowth of an exploratory investigation of the feasibility of spray drying of materials in solution by using direct‐contact heat transfer from a hot liquid rather than a gas to vaporize the solvent from the drops. Unexpectedly, it was found that drops suspended in a hot liquid had to be superheated to a very extreme degree in order to initiate vaporization. This effect was of such interest that the investigation was modified to a fundamental study of the vaporization of drops containing no dissolved solids. The results are closely related to problems of bubble formation in boiling, cavitation, and in the evolution of gases from supersaturated solutions. The experimental technique developed in this study is believed to be unique and capable of giving quite accurate data on homogeneous nucleation in superheated drops. After a discussion of the theory of homogeneous nucleation in pure liquids, the theory is extended to the formation of bubbles in superheated drops. The theoretical predictions were found to be in close agreement with the experimental results.
The economic design of mixer‐settler extractors
Authors: Treybal Robert E. 
Published: June 2004

AbstractRelationships are developed for establishing the most economic values of the major variables of a liquid‐extraction process, including the concentrations of solute in recycled solvent and rejected raffinate, the solvent‐to‐feed ratio, and for mixer‐settlers certain of the design features. Consideration is given to costs of extraction and solvent recovery, as well as to the value of unextracted solute and lost solvent. For the design of mixer settlers scale‐up relationships are developed to permit prediction of the stage efficiency of a large extractor from experimental data taken on a small scale. These are expressed in terms of a scale‐up index relating the relative size of the mixer with the volumetric rates of liquid flow. It is shown that the cost of multistage extractor increases with scale up in a different fashion from the stage efficiency, depending upon the scale‐up index used. A detailed study of the costs for a typical case led to the development of economic scale‐up indexes which, because they cover nearly a fivefold ratio of fixed to operating costs, are of fairly general utility. The common practice of scaling up with equal holding times on the large and small scale is shown to be amply safe from the point of view of stage efficiency to be realized on the large scale but usually uneconomic.Simplification of the complete system of equations permits rapid estimation of the most economic circumstances for any type of countercurrent extractor of which the cost per stage is proportional to Qg.
The vapor‐phase catalytic hydration of ethylene oxide to glycols
Authors: Metzner A. B. , Ehrreich J. E. 
Published: June 2004

AbstractThe vapor‐phase reaction between ethylene oxide and water to form glycols has been carried out under a wide range of conditions with particles of polystyrene–sulfonic acid ion exchange resins used as catalysts. The rates observed appeared to be directly proportional to the product of the partial pressure of ethylene oxide and the amount of water sorbed by the resin. By use of the Brunauer, Emmett, and Teller equation to describe the amount of water sorbed by the resin, the experimental data were correlated over a sixty‐fold range of reaction rates with a mean deviation of 15%.To obtain data of value in elucidating reaction mechanisms, the reactor was usually run under “differential” conditions, that is low conversions. However in a few runs conversions of as high as 54% were obtained for a contact time of 0.02 sec. The ratio of ethylene glycol to higher glycols (selectivity) obtained varied between 73 and 99% but was usually above 80% under conditions of high conversion. However it could also be reduced forcibly to produce higher glycols as the major product, if desired.
Transfer resistance and fluid mechanics
Authors: McCarter Robert J. , Stutzman Leroy F. 
Published: June 2004

AbstractPure liquids were evaporated in a wetted‐wall column into flowing streams of air to investigate the thickness and transfer resistance of gas films.It was found necessary to express Reynolds number relative to the liquid surface to correlate transfer with gas flow.Laminar and buffer layers in the gas phase were calculated from fluid‐flow principles and compared to the effective film thickness calculated from mass transfer and molecular diffusivity. Good agreement was obtained, indicating applicability of fluid mechanics to mass transfer problems.Eddy diffusivity was indicated to have a negligible effect upon the total resistance to transfer. Consequently it might be concluded that in packed towers where distances in the turbulent phase are shorter transfer between phases depends almost entirely upon molecular diffusivity.
The mechanics of vertical moving liquid‐liquid fluidized systems: I. Interphase contacting of droplets passing through a second quiescent fluid
Authors: Weaver Robert E. C. , Lapidus Leon , Elgin J. C. 
Published: June 2004

AbstractPrevious publications have shown that for solid spheres fluidized in water a unique relationship exists between the slip velocity and the system holdup. With this work as a model a method is now presented for estimating the behavior of the liquid‐in‐liquid spray column in which droplets of one phase move through a second quiescent phase.Combining the solids fluidization results with information on the single droplet terminal velocity one can obtain a design estimate of the holdup or interphase contact area for the liquid‐liquid spray column. This design estimate includes the particular nature of the liquid droplet of being susceptible to internal circulation, oscillation, and distortion.
Reaction rates in the synthesis of ammonia
Authors: Mills A. K. , Bennett C. O. 
Published: June 2004

AbstractA study has been made of the reaction rates of mixtures of hydrogen and nitrogen to form ammonia over a doubly promoted iron catalyst at 400° and 450°C. and at pressures up to 1,000 atm. In this work particular care has been taken to obtain data representing the true kinetics of the reaction. The reactor used was essentially isothermal, and the effects of diffusion have been reduced to a minimum. The results have been correlated by the use of the mechanism proposed by Temkin and Pyschev (19) with moderate success.
Heterogeneous phase equilibria of the hydrogen sulfide–carbon dioxide system
Authors: Sobocinski D. P. , Kurata Fred 
Published: June 2004

AbstractAn experimental study on the system hydrogen sulfide‐carbon dioxide was performed from the critical region to the solid‐liquid‐vapor region. For seven mixtures individual phase diagrams were determined by the establishment of dew, volume percentage liquid, hubble, critical, and triple points. A splendid study of this system had been reported earlier by Bierlein and Kay (1) for temperatures above 32°F. However from a temperature point of view this earlier work represents about one half of the phase diagram from the critical locus to the locus of triple points. Hence in this study particular attention was devoted to the lower temperature regions.Equilibrium constants were determined from 100 to 1,200 lb./sq. in. abs. Vapor and liquid equilibrium compositions from this investigation were compared with those obtained by Bierlein and Kay (1) at 20, 40, 60, and 80 atm.Solid‐liquid‐vapor loci were found to meet at a minimum temperature, lower than either of the individual pure component triple points, due to the formation of a eutectic mixture consisting of 12.5 mole % carbon dioxide. Vapor and liquid compositions in equilibrium with solid were established along the vapor‐liquid‐solid carbon dioxide and vapor‐liquid‐solid hydrogen sulfide loci.
Evaporation from drops containing dissolved solids
Authors: Charlesworth D. H. , Marshall W. R. 
Published: June 2004

AbstractA study was made of the evaporation from single drops containing solids. By means of a specially designed sensitive balance, drops were suspended over a hot‐air stream and their drying behavior was observed. Weight changes were measured during evaporation. Experimental data are presented on the time of appearance of the first solid phase and the formation of a solid crust for a wide range of drying conditions and materials. A theory is advanced for predicting the formation of a solid phase in drying a droplet containing a dissolved solid. This theory shows reasonable agreement with the experimental results. A tentative proposal for the application of the results to spray‐dryer performance is suggested.
The constant‐volume heat capacities of gaseous perfluorocyclobutane and propylene
Authors: De Nevers Noel , Martin Joseph J. 
Published: June 2004

AbstractThe constant‐volume heat capacities of gaseous perfluorocyclobutane and propylene have been measured over a considerable range of temperatures and densities with a new type of adiabatic calorimeter. This calorimeter differs from previous constant‐volume gas calorimeters in having very thin walls and being equipped with an internal motor stirrer to provide temperature uniformity. The experimental results have been compared with the predictions of the Benedict‐Webb‐Rubin and Martin‐Hou equations, by use of published values of the zero‐pressure‐constant‐volume heat capacity. The over‐all agreement is satisfactory, with a maximum difference between the experimental and calculated heat capacities of 6.7%; however the comparison reveals several interesting systematic differences between the experimental and calculated values of the derivatives of the constant‐volume heat capacity with respect to temperature and density.
Centrifugal filtration through beds of small spheres
Authors: Bingeman J. B. , Coates Jesse 
Published: June 2004

AbstractIn 1856 Darcy observed that water flowed through a sand bed at a rate proportional to the area of the bed and to the difference between the upstream and dowstream hydraulic heads and inversely proportional to the bed thickness. Since that time many investigators have accumulated masses of data in support of numerous theoretical and empirical relationships for correlating and predicting pressure drop, flow rate, and fluid and bed properties. Naturally certain areas of research have received less attention than others.Among the areas receiving least attention are flow through beds composed of particles of identical shape but mixed size, flow through unconsolidated beds composed of small particles, and flow under the influence of a centrifugal driving force. Accordingly, the flow of liquids through unconsolidated beds of small spherical particles of mixed size was investigated in two laboratory centrifugal filters. Experimental conditions were such that the flow was laminar and the cakes were incompressible. While there was some difficulty in obtaining reproducibility of cakes, the data for any particular cake were correlated satisfactorily by the Darcy equation adapted for centrifugal filtration.
Calculation of equilibrium flash vaporization curves by an integration method
Authors: Bennett C. O. , Brasket C. J. , Tierney J. W. 
Published: June 2004

AbstractTechniques for solving the equilibrium flash problem are reviewed and a new technique especially adapted for use on automatic digital computers is developed. Instead of a single equation with multiple roots being solved by an iterative process, as is usually done, the problem is rephrased as a differential equation, and a numerical integration is made. The isothermal and isobaric flash problems can be handled with essentially the same equations. The method is particularly advantageous when a complete flash curve is required and the equations can be used when a linear model of the equilibrium flash process is required.
Heat transfer characteristics of porous rocks
Authors: Kunii Daizo , Smith J. M. 
Published: June 2004

AbstractEquations are derived for predicting the effective thermal conductivity of beds of unconsolidated particles containing stagnant fluid. The effective thermal conductivity at these conditions, called the stagnant conductivity, is a function of the thermal conductivities of the solid and fluid phases, the void fraction, and, if radiation is important, the emissivity, mean temperature, and diameter of the solid particles. Comparison with the available experimental data indicates that the equations are satisfactory for fluids and solid particles of both high and low thermal conductivities.To extend the theory to beds of consolidated particles, it is supposed that consolidated beds are formed by partial clogging and cementing of beds of unconsolidated particles. With this assumption the theoretical equations for packed beds are extended to include such materials as sandstone and porous metals. The resulting expressions for the stagnant conductivity involve a consolidation parameter characteristic of the solid material. This quantity accounts for the heat transfer across the contact surfaces between cemented or clogged particles. The equations correctly predict the effect of void fraction and solid and fluid thermal conductivities on the heat transfer properties of sandstones and sintered metal systems.
Photographic study of solid‐gas fluidization
Authors: Massimilla Leopoldo , Westwater J. W. 
Published: June 2004

AbstractMotion pictures at 2,000 frames/sec. were used to measure the movements of individual solid particles and gas bubbles in a fluidized bed. Air was used to fluidize 0.028‐in. glass spheres and 200‐mesh alumina in a 3.75‐in. glass column. Aggregates were very common, and each moved as a unit. Particles and aggregates near the wall showed pronounced alternations of fast and slow movements both upward and downward. Individual particles exhibited spin. Baffles increased the bed density and decreased the particle velocities. Small bubbles rose rapidly with little change in shape. Large cavities were slow and tended to collapse and reform elsewhere.