bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mass transfer effects in hydrogenations in slurry reactors
Authors: Ruether J. A. , Puri P. S. 
Published: March 2009

AbstractThe effects of external and internal particle mass transfer resistance on rate for hydrogenations carried out on finely divided catalyst in slurry reactors are treated. A method is developed for estimating external particle mass transfer resistance from rate measurements and is demonstrated experimentally. The existence of reactions with negligible internal diffusion resistance and significant external diffusion resistance is modeled theoretically and demonstrated experimentally.
Non‐Newtonian thin films: Theory and experiment
Authors: Sylvester Nicholas D. , Tyler James S. , Skelland A. H. P. 
Published: March 2009

AbstractThe flow of thin films of Newtonian and non‐Newtonian, Power law fluids down a vertical plate was studied in the laminar and wavy flow regimes.A theoretical development based on the existence of a steady, periodic solution to the equations describing film flow was used to predict the flow characteristics of the film.Double logarithmic plots of film thickness versus Reynolds number (ReP. L.) were linear, as predicted, up to a ReP. L. = 100. The ratio of surface to average velocity was found to be approximately independent of the Reynolds number at values predicted by a laminar velocity profile. The wavelength of stable waves was found to be independent of the Reynolds number for a given fluid.
On the efficiency of a venturi scrubber
Authors: Behie S. W. , Beeckmans J. M. 
Published: March 2009

AbstractThe performance of a venturi scrubber with a 1‐in. by 3‐in. throat was determined using monodispersed uranine‐methylene blue aerosols in the size range 0.8 to 3.0μm at throat velocities ranging from 109.6 ft/sec to 245 ft/sec. Separate measurements on the water separator showed that substantial aerosol removal took place in this unit, and the efficiency of the scrubber itself was calculated from these measurements plus overall efficiency measurements on the combination scrubber and separator. These results were compared with values obtained from a theoretical model and agreement was generally satisfactory, although the theoretical efficiencies were lower than the experimental efficiencies at the highest air velocities, and viceversa. This discrepancy may be due to a number of factors which are discussed.
The use of a radio frequency induction plasma for nickel extraction from serpentine minerals
Authors: Meubus Paul 
Published: March 2009

AbstractThe behavior of low nickel content (around 0.25%) serpentine, or (Mgx Fey Niz)3 Si2O5 (OH)4 has been studied in a radio frequency generated plasma. It has been found that a magnetic phase (spinel) enriched in Ni can be separated from the products of reaction. Nickel concentrations up to 2.3% were found in this phase which also should contain up to 50% of the total Ni present in the original serpentine. Average gas temperatures ranging from 3,800°K to 6,000°K were investigated while neutral (argon) and reducing (argon + hydrogen) atmospheres were studied. Mixtures of the mineral and carbon were also submitted to the high temperature reactions
The role of pore structure in the catalytic behavior of “unaged” and “aged” silica‐alumina catalysts
Authors: Ferraiolo G. , Peloso A. , Reverberi A. , Del Borghi M. , Beruto D. 
Published: March 2009

AbstractThis is a review of research concerning the role played by the porous structure of silica‐alumina catalysts on the evolution of organic catalytic processes. A strong effect of the geometrical shape of the pores on catalytic activity and selectivity has been evidenced.The experimental results have also been interpreted by means of a simplified mathematical model, able to relate selectivity for a reaction of the type A → B → C to the geometrical features of macro‐microporous catalyst pellets, or granules.The theoretical results are in qualitatively satisfactory agreement with the experimental data.
Optimal discrete stochastic control theory for process application
Authors: Macgregor John F. 
Published: March 2009

AbstractThe design of discrete feedback controllers which minimize some linear function of the variances of the output deviations from target subject to possible constraints on the variances of the inputs, for linear systems subject to stochastic disturbances, is treated from two points of view: (1) using transfer function models to characterizing the process dynamics and autoregres‐sive‐moving‐average models to characterize the stochastic disturbances, and then solving the optimal control problem using an approach due to Box and Jenkins and a discrete version of the Wiener‐Newton theory; and (2) using state variable models to characterize both the dynamic and stochastic parts of the system, and then solving the optimal control problem using the results of dynamic programming and Kalman filtering. Practical considerations such as model forms, their identification and estimation, and the development of variance relationships that are necessary for the application of these two approaches in the process industries are discussed. The relationship between and a comparison of these two approaches is made.
Heating and cooling of flocculated and non‐flocculated slurries in tubular heat exchangers
Authors: Crewe G. F. , Simons H. P. 
Published: March 2009

AbstractThe distinctly different turbulent heat transfer characteristics of flocculated kaolin slurries are compared with nonflocculated coal slurries via modified J‐factor correlation forms for tubular exchangers. Both slurry types were statistically best‐fitted with the approximate solution Bingham plastic flow model in preference to the local shear power law. In addition, the first known turbulent slurry heat transfer cooling results are presented along with the heating results. No distinction was made between heating and cooling correlation forms because of a random scatter of experimental points.Experimental results were interpreted as followsA. Flocculated kaolin slurriesJH = (h/CpG) (C/K1)2;3= 0.027(DVρ/μLeBϕ)0.211%ω < %ω Solids < 24%ωMaximum Deviations: + 19.3%, − 17.8%B. Non‐flocculated coal slurriesJw = (h/CpG)(CpμLeBϕ/kw)2/3e−Bϕ/4)=0.0285 (DVρ/ μLeBϕ)−0.213%w > %w Solids < 33.5%.Maximum Deviations: + 17.8%, ‐ 11.1%
The distribution of solids between stages in baffled fluidized beds
Authors: Nguyen X. T. , Bergougnou M. A. , Baker C. G. J. 
Published: March 2009

AbstractThe partition of solids between stages in baffled fluidized beds has been studied. The bed, 9 ft tall and 11 in I. D., was divided into two or three stages by horizontal perforated plate baffles having open areas ranging from 11.5 to 34%. The spacing between baffles was varied from 1.5 to 3.5 ft. Four fluidized solids were studied and the velocity of the fluidizing air was varied between 0.2 and 2.5 ft/sec. A correlation was developed which enabled the solids holdup in each stage to be predicted.
Symposium on application of pulse techniques to kinetic measurements: Une nouvelle formulation dynamique des interactions fluide solide — Application à des mesures de diffusivités intraparticulaires et de constantes d'équilibre d'adsorption
Authors: Villermavx Et Jacques , Matras Didier 
Published: March 2009

AbstractA general model of the dynamics of linear chromatographic interactions between a fluid and a solid is proposed, according to the following steps:

Analysis of the processes occurring at the particle level. Transfer function relating the mean concentration in the particle to the surface concentration. Contribution of external and internal mass transfer. Approximation by a first order system.
Transfer function of a mixing cell containing solid particles. Approximation by two coupled first order systems.
Generalization to any kind of flow. Association of mixing cells in series: model of a chromatographic column. Mean and variance of the impulse response.

Two experimental examples are given:

Measurement of the internal tortuosity and ethane adsorption isotherms in microporous alumina pellets using a spontaneously jet stirred gas solid reactor.
Determination of the effective diffusivity of argon in porous alumina beads using the so called “two measurements chromatographic method”.
Unsteady viscometric flow
Authors: Smith J. R. , Tory E. M. 
Published: March 2009

AbstractPoncin's Navier‐Stokes solution for the falling head viscometer is obtained more directly by a Laplace transform method. Approximations which facilitate numerical evaluation are derived and Grumbach's result for an infinite capillary is obtained as a limiting case. A systematic series of approximations to the general, unsteady Euler duct equation are solved analytically. All solutions are compared with a numerical integration of the complete Euler duct equation. It is shown that all results become indistinguishable for sufficiently small Reynold's number and that the kinetic energy effect is clearly the major inertial effort.
The uniform film model for the gravitional approach of fluid drops to plane and deformable interfaces
Authors: Hartland S. , Robinson J. D. 
Published: March 2009

AbstractAxisymmetric drainage within thin planar or spherical films of viscosity μ, area A and uniform thickness δ at time t is governed by the equation

where F is the force pressing on the film and n the number of immobile interfaces. Assuming that the film ruptures at a critical thickness which is independent of the physical properties and applied force, expressions of the form

may be obtained for drops approaching rigid and deformable interfaces and rigid spheres approaching deformable interfaces. The values of the exponents a, b and c suggest that an increase in drop volume, V, and density difference, δρ, and a decrease in interfacial tension, σ, should increase the coalescence time, τ, in liquid‐liquid systems. However in gas‐liquid systems an increase in δρ should decrease the coalescence time.The variation of δ with time was obtained experimentally from capacitance measurements. For drops approaching a deformable interface, the corresponding values of n are always close to 1 and in the region between 0 and 2. The values increase when the interfaces are made less mobile by adding surface active agents; they are also larger for drops approaching a rigid interface and for rigid spheres approaching a deformable interface. Consequently the uniform film model adequately describes the approach of drops to rigid and deformable interfaces.
Transfert de chaleur par contact direct entre deux liquides immiscibles dans un mélangeur‐décanteur
Authors: Paquet M. , Grenier P. 
Published: March 2009

AbstractIt is shown by means of two performance criteria that a mixer‐settler combination can successfully be used as a direct contact heat transfer device between two immiscible liquids. This combination was operated under steady‐state conditions. The two criteria were a heat transfer efficiency and an overall volumetric heat transfer coefficient.The experimental results show a considerable increase in efficiency and in the overall coefficient with increasing rotational speed of the agitator. These two criteria are also influenced by the ratio of heat flow rates of the two liquids; one particular value of this ratio results in a minimum heat transfer efficiency; at another value the volumetric coefficient passes through a maximum.
Heat and mass transfer from cylinders to a turbulent fluid stream — A critical review
Authors: Boulos Maher I. , Pei David C. T. 
Published: March 2009

AbstractA review is made of recent experimental and theoretical work on the transfer of heat and mass between a circular cylinder and a turbulent fluid stream in cross flow. Special attention has been given to the transport mechanism over the wake region and the different approaches used to model it. The overall and boundary layer transport characteristics are briefly discussed. The review is limited to investigations under subcritical flow conditions over the Reynolds number range from 103 to 105.
The removal of copper, cadmium, and lead ions from dilute aqueous solutions using foam fractionation
Authors: Huang Robert C. H. , Talbot Frank D. 
Published: March 2009

AbstractThe removal of copper, lead and cadmium ions from aqueous solution by foam fractionation using sodium dodecylbenzene sulphonate (NaDBS) has been experimentally studied and theoretically predicted for solutions with a pH less than 4. A mathematical model of the system consisting of the equilibrium relations of chemical reactions occurring in the system was solved for the equilibrium concentration of all ions in the solution. Based on this equilibrium concentration and the effective radius of the hydrated ion, a modified theory of the Gouy‐Chapman diffuse double layer(9) was used to predict the distribution factor of the metal ions. The work was extended to systems containing two metal ions for the determination of the separability of the ions with respect to each other.It was found that the distribution factor for solutions containing one metal ion could be predicted theoretically for a bulk solution pH less than four. Deviation of results above this pH was attributed to the limitations of the bulk solution reaction model because it did not include reactions for the formation of poly hydroxyl and poly nuclear hydroxyl complexes. Good agreement was also obtained between experiment and theory in the separability study. The results indicate that the order of removal of the ions from solution is Pb++ > Cd++ > Cu++. This sequence is the reverse order of the effective radii of the hydrated ions. The results support the fact that the mechanism for removal of the ions from solution is that of electrical attraction and that selectivity depends upon the charge and size of the hydrated ion.
Hydrogen reduction of the chlorides of cobalt and nickel
Authors: Rigg Tyson 
Published: March 2009

AbstractExperimental results on the reduction of compacted pellets of the chlorides of cobalt and nickel are reported. The kinetics of the processes are considered in the light of the chloride vaporization mechanism previously proposed to account for the reduction of ferrous and chromous chlorides. Although all these reduction processes are superficially similar, substantial differences in reaction topography have been observed. These differences are attributed to the wide range of vapour pressure displayed by the various metal chlorides over the range of experimental conditions employed. Possible technical exploitation of these reactions is briefly discussed.
The pyrolysis of extracted solids from oxidized kraft black liquor after lignin precipitation
Authors: Bruley A. J. , Cook W. G. , Ross R. A. 
Published: March 2009

AbstractA laboratory investigation of the possibilities for the reduction of odor from Kraft mill stack gases by lignin precipitation from oxidized Kraft black liquor and subsequent pyrolysis of the filtrate solids has been carried out. Samples of oxidized black liquor were acidified with sulphuric acid and the lignin precipitate extracted. The extraction scheme indicates that > 90% w/w of the sodium in the original black liquor samples can be retained in the filtrate after lignin removal at final pH 2.0. The evaporated filtrate solids containing the bulk of the black liquor inorganic chemicals were pyrolyzed and the evolved hydrogen sulphide, methyl mercaptan and dimethyl sulphide monitored by gas‐chromatography. Gas‐chromatograph traces displaying the increase and decrease of methyl mercaptant evolution levels on pyrolysis of the filtrate solids to increasing temperatures are shown.A thermogravimetric technique was used to investigate the decomposition rates of the extracted samples and these rates correlated with the levels of sulphur gases evolved on pyrolysis. Heats of combustion were determined by bomb calorimetry. Sulphur losses from the filtrate solids and the Kraft black liquor total solids are compared. The results show a significant decrease in the evolution of organo sulphur gases from samples of ligninextracted black liquor solids in comparison with original total solids samples, an increase in the level of hydrogen sulphide evolution however, presents a problem.
Discrimination statistique des modèles: Application à l'étude de l'écoulement dans un réacteur dynamique à agitation
Authors: Tho Et Nguyen‐Xuan , Rouleau Denis 
Published: March 2009

AbstractIt often happens that those who carry out experiments must choose between two or more possible theoretical models; the use of the statistic discrimination enables them to make a judicious selection.Several theoretical models have been proposed to represent the actual flow in a dynamic reactor involving stirring in a gas phase. Experiments have been carried out using propylene as a tracer and helium as a gas carrier, and involving feeding rates varying between 2 c. c./second and 33 c. c/second and rotation speeds comprised between 0 and 1000 rpm. The statistic discrimination of models enables to detect an inactive area in the reactor when the rates are lower than 11.8 c. c./second.
Bubble nucleation in saturated and subcooled boiling
Authors: De P. L. , Judd R. L. 
Published: March 2009

AbstractAn experimental investigation is reported for water boiling at atmospheric pressure on a copper surface in which the nucleation of bubbles was observed at an artificial nucleation site for five levels of heat flux between 11,700 Btu/hr ft3 and 19,600 Btu/hr ft2 and various levels of subcooling from 0°F to 32°F. Four mathematical models were evaluated. The experimental results were found to provide excellent agreement with the predictions of the Han and Griffith model for bubble nucleation.
Numerical studies of viscous stagnation point flows
Authors: Raal J. D. , Code R. K. 
Published: March 2009

AbstractA rapid finite‐difference procedure for computing stagnation point flows at a given Reynolds number in terms of stream function and vorticity distributions is described. The method is illustrated for spherical and cylindrical curvature for Reynolds number ranges of 1 ≤ Re ≤ 400 and 4 ≤ Re ≤ 100 respectively. Predicted radial and angular velocity distributions in the frontal region are compared with results from numerical solutions of the full elliptic equations of motion. The use of a modified potential flow outer boundary condition reduces the region of numerical computation.
Continuous ion exchange in fluidized beds
Authors: Slater M. J. 
Published: March 2009

AbstractA mathematical model has been developed for prediction of the performance of a continuous ion‐exchange column, comprising a series of fluidized beds of resin, operated with periodic flows of both phases. Simple small‐scale tests provide the data required in calculations. Experimental work was carried out on uranium extraction from unfiltered ore leach pulps and clarified liquors.
Spreading of crude oil on an ice surface
Authors: Chen E. C. , Overall J. C. K. , Phillips C. R. 
Published: March 2009

AbstractThe gravity‐viscous spreading of crude oil on artificially prepared ice surfaces was investigated. Five different types of crudes were studied with three surface roughnesses at ‐14°C. Crude oil No. 1 was also studied at ‐8 and ‐3°C. All spreading experiments were made with an oil volume of 45 and 20 ml. Regardless of temperature, surface roughness, oil type and oil volume, all data may be correlated by: where ρ, V and μ are the density, volume and viscosity of the oil, respectively, R is the radius of the oil slick, t is time, C is a constant and g is the acceleration of gravity.
A direct method for calculating ternary vapor compositions from total‐pressure measurements
Authors: Polak Jiri , Lu Benjamin C. ‐Y. 
Published: March 2009

AbstractTernary vapor compositions have been successfully calculated from total‐pressure measurements for four systems by means of a modified direct method, which involves the previously proposed concept of hypothetical binary mixtures, and permits the numerical integration using a simple P‐x relationship. The results of the systems tested further indicate that the ternary y values predicted from only binary P‐x data are not significantly different from the y values obtained when binary together with ternary P‐x values were used in the calculation, provided that the initial fit of binary P‐x data is successful.
Gas‐gas equilibrium: High pressure limits
Authors: Streett William B. 
Published: March 2009

AbstractRecent experimental studies of phase behavior in mixtures of light gases, at pressures up to ten thousand atmospheres, provide information about high pressure boundaries to regions of gas‐gas equilibrium. It is shown that these regions are generally bounded on the high pressure side by a three‐phase region of the type solid‐gas‐gas, which results from the solidification of the less volatile component. In some cases the gas‐gas phase separation terminates at a critical end point formed by an intersection of the critical line with the three‐phase region. However, the available evidence suggests that in other cases gas‐gas phase separations may persist to very high temperatures at very high pressures, perhaps even to the limits at which atomic and molecular structure begin to break down.
An automated apparatus for precision density measurements of liquids
Authors: Adams W. A. , Yank R. , Christie R. O. , Kruus J. 
Published: March 2009

AbstractAn electronic controller is described which permits the automatic sequential mixing of two solutions. A small aliquot of each of the solutions produced is injected in turn into an electronic density meter displacing the previous solution and a digital recording is made of temperature and density. Results of a partial molal volume study of aqueous NaCl solutions at 25°C are presented (v_° = 16.621 cm3 mol‐1, S*v = 1.848 cm3 11/2 mol3/2, and bv = .0.138 cm3 1 mol12).
Gas flow patterns in spouted beds
Authors: Van Velzen D. , Flamm H. J. , Langenkamp H. 
Published: March 2009

AbstractProfiles of local spout gas velocity, in both radial and vertical directions, were determined with a Prandtl tube, and of annulus gas velocities from static pressure measurements. It was deduced that the parameter governing the spout gas velocity is the momentum transfer rate at the gas inlet, and not particle characteristics. The results also showed evidence of downward gas flow in the annulus and thus recirculation of gas in the vicinity of the entrance nozzle, which is an hitherto unknown aspect of the spouted bed gas flow pattern.
Pressure drop and flowrate characteristics of a liquid phase spout‐fluid bed at the minimum spout‐fluid flowrate
Authors: Littman H. , Vukovic D. V. , Zdanski F. K. , Grbavčić Ž. B. 
Published: March 2009

AbstractData on the minimum spout‐fluid flowrates and the pressure drop in the annulus at that flowrate are presented as a function of bed height and nozzle diameter for a bed spout‐fluidized with water. The column was 62.6 mm. in diameter and contained 3.09 mm. glass particles. The particle Reynolds number at the minimum fluidizing velocity was 91.6.A plot of the annular vs. the nozzle flowrate shows that the minimum spout‐fluid flowrates fall on a straight line between the minimum fluidizing and minimum spouting flowrates. The annular pressure drop is explained using an extension of the theory of Mamuro and Hattori.
Pressure drop, bed expansion and liquid holdup in a three phase spouted bed contactor
Authors: Vukov ÍC D. V. , Zdanski F. K. , Vunjak G. V. , Grbavčić Ž. B. , Littman H. 
Published: March 2009

AbstractData on the pressure drop, bed expansion and liquid holdup in a three phase spouted bed contactor with an initial bed height of 243 mm. were obtained as a function of the gas and liquid flowrate. Polyethylene spheres 10 mm. in diameter with a density of 320 kg/m3 were spouted in a 194 mm. column using a 30 mm. nozzle.The spouted bed contactor with gas and liquid mass flow‐rates of 2.18 and 1.88 kg/m2 sec, respectively had similar pressure drop per unit area of particle surface, total liquid holdup per unit volume of operating bed, and “active” holdup, as a fluidized contactor.