bluuebunny/crossref_metadata_2025_split huggingface dataset:
Détermination du facteur d'efficacité et du coefficient de tortuosité d'un catalyseur au vanadium pour l'oxydation du dioxyde de soufre
Authors: Herce J. L. , Gros J. B. , Bugarel R. 
Published: March 2009

AbstractLes anteurs présentent les résultats cinétiques obtenus lors de l'oxydation de SO2 à la pression atmosphérique sur un catalyseur à base de vanadium pour des grains de catalyseurs d'un diamètre de 0,04–0,05 cm, 0,0115–0,02 cm, 0,15–0,16 cm, 0,2–0,21 cm et 0,3 cm. La gamine de température varie de 500 à 630°C. A partir de la comparaison de l'efficacité des grains et d'un modèle de calcul de cette efficacité, ils en déduisent la diffusion effective de SO2 dans le grain et le facteur de tortuosité du catalyseur. Ces valeurs sont comparées avec celles obtenues par Kadlec et col. et Livbjerg et col.
Evaluation of capital cost data: Heat exchangers
Authors: Woods Donald R. , Anderson Susan J. , Norman Suzanne L. 
Published: March 2009

AbstractCapital cost correlations are given for heat exchangers and furnaces. Correlations available in the literature and current data are compared on a consistent basis. Forty‐six graphs show the relative magnitude of the different correlations and the recommended correlation for each type of equipment is summarized in a table. Some data on the costs of installing heat exchange equipment are given.
Turbulent flow in helically ribbed pipes
Authors: Shook C. A. , Sagar S. K. 
Published: March 2009

AbstractVelocity profiles, turbulence intensities and Reynolds stresses were determined in pipes containing three helical ribs equally spaced on the pipe wall. Pitch to diameter ratios of 8 and 11 were used. The fluid considered was air and measurements were made with X wire probes calibrated for pitch and yaw effects.The ribs appeared to affect the axial flow via the tangential component which reached a maximum below the ribs in most cases. Evidence of increases in mixing length near the wall and decreases in the central core was obtained. These are in agreement with recent theoretical predictions of other workers. Turbulence intensities were not significantly altered when normalized with the usual friction velocity.
Characterisation of inelastic poweriaw fluids using falling sphere data
Authors: Uhlherr P. H. T. , Le T. N. , Tiu C. 
Published: March 2009

AbstractTwo simple methods are presented for the characterization of inelastic power law fluids from falling sphere data. The methods involve the application of shear rate or shear stress correction factors which have been derived theoretically using Slattery's solution for creeping flow about spheres. Flow curves obtained using these methods are in excellent agreement with those measured on a Weissenberg rheogoniometer for 0.83 > n > 1.0.The experimentally determined drag coefficients are found to be in good agreement with the predictions of Slattery's creeping flow first approximation solution.The wall correction factors of Faxen and Francis appear to be valid for inelastic non‐Newtonian fluids up to a diameter ratio of at least 0.08.
Viscous effect on stagnation depth of bubbles in a vertically oscillating liquid column
Authors: Marmur Abraham , Rubin Eliezer 
Published: March 2009

AbstractPrevious theories which evaluated the stagnation depth of bubbles in a vertically oscillating liquid column are reviewed, and it is pointed out that they used an insufficient criterion for determining stagnation. The correct condition, which states that stagnation means zero mean velocity rather than acceleration, necessitates the solution of the equation of motion of the bubble, and thus viscous drag has to be included. It is shown, in accordance with available experimental data, that the value of the dimensionless group M = ω4A2ρ/2gPo (which gives the stagnation depth h) is not in general a constant, but is dependent on four other dimensionless groups. Although there is no reliable information concerning the drag coefficient curve for such a situation, it is suggested, on the basis of comparison between different drag coefficient curves, that the high values of M reported in the literature and not accounted for by theory are due to bubble shape deviations from sphericity in viscous flow.
An experimental study of convective instability in the thermal entrance region of a horizontal parallel‐plate channel heated from below
Authors: Hwang G. J. , Liu Cheng‐Liung 
Published: March 2009

AbstractThis paper presents results of an experimental investigation on the onset of longitudinal columnar vortices due to buoyant forces in the thermal entrance region of a horizontal parallel‐plate channel heated from below. Channels with width 30 cm and heights h = 2, 3 and 4.5 cm were employed in the experiment. The instability of the convective motion is caused by the effects of temperature gradients in both longitudinal and vertical directions and was observed by a direct flow‐visualization technique using smoke. Photographs of the front and top views of the vortex rolls are presented. Experimental results indicate that the wave number of vortex rolls remains constant along the flow direction and tends to approach the theoretical value as the channel width‐height ratio increases. It was also observed that the critical Rayleigh number from flow visualization is 1.4 to 10 times higher than the critical value from linear theory.
Gas‐liquid mass transfer coefficients for cocurrent upflow in packed beds — effect of packing shape at low flow rates
Authors: Alexander B. F. , Shah Y. T. 
Published: March 2009

AbstractGas‐liquid mass transfer coefficients were determined by oxygen desorption for cocurrent upflow in packed beds. Data are included for seven different catalyst supports, four of which have not appeared previously in the literature. Very low flow rates (liquid: 0.9–6.0 mm/s, gas; 1.5–31 mm/s) of interest in pilot‐scale catalytic hydrogenation, were investigated. The results correlated well with liquid and gas flow rates for each packing. In addition, the data for all packings were correlated reasonably well by the energy dissipated in the liquid phase.
Mass transfer characteristics of horizontal agitated contactors
Authors: Joshi J. B. , Sharma M. M. 
Published: March 2009

AbstractThe values of effective interfacial area, a, and liquid side mass transfer coefficient, kLa, were obtained in 0.385, 0.57 and 1.0 m i.d. horizontal agitated contactors by using chemical methods. Propeller type of impellers were employed for agitation. Two modes of operation were studied: (i) surface aeration and (ii) sparging of gas. The impeller speed was varied from 50 to 700 rev/min, and the nozzle gas velocity was varied from 40 to 160 m/s. The effects of impeller spacing, liquid submergence and nozzle gas velocity on the values of a and kLa were investigated. A scale‐up criterion is discussed.
Kinetics of the liquid phase reaction between carbon dioxide and diethanolamine
Authors: Coldrey P. W. , Harris I. J. 
Published: March 2009

AbstractThe kinetics of the reaction between carbon dioxide in aqueous solution and aqueous diethanolamine have been studied using the thermal flow method. The data indicate that the kinetics of the reaction is complex. The particular mechanism proposed consists of two reactions which initially compete for the available carbon dioxide. One of these reactions is reversible, and regenerates carbon dioxide as the overall reaction proceeds. The species participating in the proposed reversible reaction were not identifiable from the data obtained.
Kinetics of hydrogen reduction of cobalt sulfide
Authors: Fahim M. A. , Ford J. D. 
Published: March 2009

AbstractThe hydrogen reduction of cobalt sulfide (Co9S8) at atmospheric pressure in the temperature range 600–800°C has been experimentally investigated. When sulfide pellets were used, the rate constants were overestimated. The true intrinsic kinetics of this reaction were obtained from another set of experiments using sulfide powder, under conditions such that the topochemical shrinking core model in the chemical control regime could be applied. In the temperature range 600–737°C, the rate constant for the powder reaction could be expressed as:k = 15,600 exp (–27,800/RT)Above 780°C, cobalt metal whiskers were formed, and this led to swelling and cracking of pellets.
pH control of a continuous precipitator
Authors: Attarian C. , Baker C. G. J. , Svrcek W. Y. 
Published: March 2009

AbstractThe size distribution of precipitates formed in a double decomposition reaction has been found previously to be highly sensitive to pH. Consequently, automatic control of pH is necessary to maintain a constant product size distribution. In the present study, steady‐state, dynamic, and pH control tests were performed on a continuous precipitator in which calcium carbonate was produced. Agreement between the experimental dynamic response and that predicted by a model based on equilibrium and stoichiometry was poor. However, satisfactory feedback control of the pH was achieved using proportional plus integral action. Simultaneous measurements of the precipitate size distribution using a Coulter Counter demonstrated that this resulted in good conrol of the mean paricle size.
Viscous effect on stagnation depth of bubbles in a vertically oscillating liquid column
Authors: Marmur Abraham , Rubin Eliezer 
Published: March 2009

AbstractPrevious theories which evaluated the stagnation depth of bubbles in a vertically oscillating liquid column are reviewed, and it is pointed out that they used an insufficient criterion for determining stagnation. The correct condition, which states that stagnation means zero mean velocity rather than acceleration, necessitates the solution of the equation of motion of the bubble, and thus viscous drag has to be included. It is shown, in accordance with available experimental data, that the value of the dimensionless group M = ω4A2ρh/2gPo (which gives the stagnation depth h) is not in general a constant, but is dependent on four other dimensionless groups. Although there is no reliable information concerning the drag coefficient curve for such a situation, it is suggested, on the basis of comparison between different drag coefficient curves, that the high values of M reported in the literature and not accounted for by theory are due to bubble shape deviations from sphericity in viscous flow.
Mass transfer between solid spheres and oscillating fluids — A critical review
Authors: Taweel A. M. Al , Landau J. 
Published: March 2009

AbstractRelative oscillatory motion between solid particles and a fluid increases the rate of interphase mass transfer due to the establishment of secondary flows (acoustic streaming). A critical survey of published data shows that mass transfer is well correlated by a theoretically founded dimensionless relation of the form

where K, a, b and d depend on the Schmidt number. The equation successfully correlates experimental data for both gases and liquids over a range of frequencies F < 1 Hz to F ∼ 106 Hz, provided the amplitude to diameter ratio A/D is below 0.75. At higher values of this parameter, \documentclass{article}\pagestyle{empty}\begin{document}$ \bar N_{Sh} $\end{document} is better predicted by a quasi‐steady model which no longer depends on A/D.
Gas‐liquid mass transfer coefficients for cocurrent upflow in packed beds — Effect of packing shape at low flow rates
Authors: Alexander B. F. , Shah Y. T. 
Published: March 2009

AbstractGas‐liquid mass transfer coefficients were determined by oxygen desorption for cocurrent upflow in packed beds. Data are included for seven different catalyst supports, four of which have not appeared previously in the literature. Very low flow rates (liquid: 0.9–6.0 mm/s, gas; 1.5–31 mm/s) of interest in pilot‐scale catalytic hydrogenation, were investigated. The results correlated well with liquid and gas flow rates for each packing. In addition, the data for all packings were correlated reasonably well by the energy dissipated in the liquid phase.
The role of paraffin wax in the formation of minor products in the catalytic cracking of petroleum distillates over La‐Y
Authors: John Thomas M. , Wojciechowski Bohdan W. 
Published: March 2009

AbstractAn investigation of the role of paraffin wax in the catalytic cracking of wax‐bearing petroleum distillates has been carried out in a fixed‐bed reactor containing La‐Y catalyst over a temperature range from 482° to 524°C.By using the concept of initial product selectivity derived from the time‐on‐stream theory of catalyst decay, it was found that increasing the wax content of the feedstocks resulted in an increase in the yield of C5+ gasoline and a decrease in the yields of most of the gaseous products and of coke. Ethane and propylene and the olefin content of the gasoline increased in yield with the addition of wax. The mixing of cracking feedstocks has only a linear effect on the reactivity and no synergistic effects in any of the observed properties of the reaction are in fact observed.
Velocity and momentum of vortex rings in relation to formation parameters
Authors: Baird M. H. I. , Wairegi T. , Loo H. J. 
Published: March 2009

AbstractThe formation of ring vortices under water has been studied at orifices of diameter 2.54 to 6.35 cm and formation times from 0.04 to 0.68 s, with orifice Reynolds number between 3 × 104 and 3 × 105. Ciné photographs of the formation process were taken, and the initial velocity of the vortices was found in general to be one half of the velocity of flow through the orifice. The translational momentum of the vortex rings was measured by a surge‐tube method. It was concluded that the formation process is most efficient when the length of the impulsive jet is not more than two orifice diameters.
Dispersion from a point source with and without chemical reaction in semi‐bounded waters
Authors: Wang S. T. , Mcmillan A. F. , Chen B. H. 
Published: March 2009

AbstractAn unsteady, three dimensional diffusion equation has been solved for the dispersion of pollutants, with or without chemical reaction, from an instantaneous point source in a semi‐bounded water under the influence of a vertical shear.The solution, which has been shown to be valid for two limiting cases: unbounded waters and large diffusion time, shows that the concentration ellipsoids would elongate themselves under the influence of a vertical shear, although the degree of elongation would also depend on diffusion coefficient and diffusion time. The effect of chemical reactions is to reduce the concentration level around the moving center of mass. The boundary affects profoundly the concentration distribution when the source is close to the shore.
Fractionnement des mélanges de protéines par électrophorèse convective
Authors: Sanchez Victor , Casademont Ernest , Mahenc Jean 
Published: March 2009

AbstractA new apparatus is proposed which allows the fractionation of protein mixtures by convective electrophoresis. The cell is arranged as a stack of elementary units, each of which consists of two compartments bounded by semi‐permeable membranes and separated by a permeable cotton diaphragm. The solutions are circulated by forced convection, either co‐current or eounter‐current. The development of transport equations has made it possible to define which parameters control separation. An experimental study has been carried out to show the effect of these parameters (potential difference, rate of convection, number of elementary units) on the concentration of proteins from dilute solutions and on the fractionation of binary mixtures. Finally, predictive calculations are attempted in order to define the optimum operating conditions, and in order to scale‐up the apparatus used.
Foam fractionation of zinc
Authors: Siy Robert D. , Talbot Frank D. 
Published: March 2009

AbstractThe foam fractionation of zinc ion from dilute aqueous solution with sodium dodecylbenzene sulfonate (NaDBS) as collector was studied using a single stage foam apparatus. Results are expressed as the surface excess and distribution factor of zinc. The optimum pH for the removal of zinc was found to be from 3.0 to 5.0. Efficient removal of zinc (high distribution factor) took place at low zinc ion concentration (less than 5 ppm) and low collector concentration consistent with a stable foam. The order of effectiveness in the removal of zinc by various forms of collector was found to be KDBS < NaDBS < LiDBS < HDBS.
A modified heil‐prausnitz equation for excess gibbs energy
Authors: Vetere Alessandro 
Published: March 2009

AbstractAn equation for the Gibbs excess energy, similar to that of Heil‐Prausnitz, is derived on the basis of the lattice theory of fluids. This equation takes into account both the enthalpic and entropic contributions to GE for liquid mixtures, and in addition uses the αij parameter of Renon‐Prausnitz. It is compared in the one‐ and two‐parameter forms with the analogous equations of Wilson, NRTL and Heil‐Prausnitz for 44 binary liquid‐vapour systems, and with the NRTL equation for 2 ternary liquid‐liquid systems. Rules are given for calculating the αij parameter.Methods are also reported for predictive calculations of the binary interaction parameter g12 based on the properties of the pure fluids.
Liquid‐liquid equilibrium for the activity coefficient determination: Effect of mutual solubility between binary systems and auxiliary solvents
Authors: Kikic Ireno , Alessi Paolo 
Published: March 2009

AbstractThe method proposed earlier by the authors for the determination of activity coefficients by liquid‐liquid equilibrium using water as auxiliary solvent is extended by making use of other solvents. The effect of mutual solubility on the determination of activity coefficients is discussed. A correction to be applied to the experimental data is proposed, and the activity coefficients so obtained are thermodynamically consistent. The method can be applied not only to hydrocarbon mixtures, but also to solute‐polar solvent mixtures.
A sinusoidal pressure response method for determining the properties of a porous medium and its in‐situ fluid
Authors: Bennion D. W. , Goss M. J. 
Published: March 2009

AbstractFrequency response data from sinusoidal pressure experiments using liquids can be used to characterize the porous medium and its fluid properties. This paper examines the theory and presents correlations to help design experiments. Experiments were designed to check the theory. Measurements were made using a synthetic oil in an unconsolidated medium. Equipment was designed to generate pressure sine waves whose upper frequency limit was in excess of 1,000 rad/s.The theory indicates that there are definite frequency limits which may be used if the equations are to adequately describe the data. As the frequency and/or permeability increases, the inertial terms become important. This study shows that practical use can be made of existing theory to increase our ability to describe the flow of fluids in porous media.
Expansion de couches fluidisées par des liquides
Authors: Riba J. P. , Couderc J. P. 
Published: March 2009

AbstractThe expansion properties of liquid fluidized beds are distinctly different for low void fractions (∈ < 0.85) and high void fractions (∈ > 0.85). Three different forms of correlations are compared for these two ranges of void fraction.
Segregation phenomenon in spouted beds
Authors: Piccinini N. , Bernhard A. , Campagna P. , Vallana F. 
Published: March 2009

AbstractPreliminary experiments with spouted beds of binary mixtures of particles have shown that segregation according to size or density clearly occurs, with heavier particles going to the upper inside part of the annulus. Segregation tendency becomes less pronounced with increasing gas flow rate.During continuous operation, the concentration of coarse particles in the discharge stream was found to be initially lower than in the feed but it increased within a short time (10–50 min) to the feed concentration. However, the proportion of coarse particles in the bed solids (x) always remained higher than in the solids leaving the bed (y). A state of equilibrium was found to exist between these two concentrations, described by the following equation:y = xnThe exponent n turned out to be a function of gas velocity and particle size of the individual components of the mixture, but, not of their proportions, nor of feed rate. An empirical correlation for n is proposed.
Liquid solidification in a convectively‐cooled parallel‐plate channel
Authors: Cheng K. C. , Wong Sum‐Lok 
Published: March 2009

AbstractA theoretical analysis of liquid solidification in the thermal entrance region of a parallel‐plate channel with a uniform external convection is carried out by using the confluent hypergeometric function in the solution for laminar flow and steady‐state conditions. Theoretical results are obtained for liquid solidification‐free length, liquid‐solid interface profile, pressure drop, bulk temperature, heat transfer rate and local Nusselt number for the cases of Biot numbers Bi = 0.25, 0.5, 1, 2, 10, ∞, superheat ratios ∈ = 1, 2, 4, 8, Pr = 13.2 and k1/k2 = 0.25 using 20 eigenvalues. The convective boundary condition allows one to evaluate the effect of external convection cooling including the effect of thermal insulation.
Experimental study of mass transfer due to an impinging rectangular jet
Authors: Masliyah Jacob H. , Nguyen Trung T. 
Published: March 2009

AbstractMass transfer from a flat surface due to an impinging free jet issuing from a rectangular tube has been measured for a Reynolds number range of 760–1800 using laser holographic interferometry. In the wall jet region, the local Sherwood number is a strong function of position, both in radial and angular directions. Regression equations for the local Sherwood number are given.
Desulfurization of oil sands coke
Authors: Parmar B. S. , Tollefson E. L. 
Published: March 2009

AbstractResearch done on the development of a process to desulfurize oil sands coke is described. Solvent extraction, steam treatment alone, steam treatment in the presence of sodium compounds, treatment with steam and air mixtures, hydrodesulfurization and preoxidation followed by hydrodesulfurization have been investigated. It has been found that oxidative pretreatment of oil sands coke with air at low temperatures enhances the rate of sulfur removal during the subsequent hydrodesulfurization. Up to 75% of the sulfur present in the oil sands coke can be removed by preoxidizing the coke at 530°F for eight hours followed by hydrodesulfurization with hydrogen at 1200°F for eight hours using shallow fluidized beds of –20 mesh coke particles. Yields of purified coke of approximately 56% were obtained from this process.
Etudes des paramètres d'opération du procédé de fermentation du d'glucose, d'mannose et d'galactose
Authors: Pineault G. , Pruden B. B. , De Kee D. 
Published: March 2009

AbstractThe effect of pH, temperature and stirrer speed on the alcohol yield in the fermentation of d‐Glucose with yeast (S. cerevisiae) has been studied using factorial design. The results of this study, coupled with other published work have shown that the maximum alcohol yield was at pH = 5.0, Temperature = 32°C and stirrer speed = 700 rpm. (Stirrer Reynolds number = 29,200, 6 bladed turbine).The optimum conditions for d‐Glucose have been applied in the fermentation of d‐Mannose and d‐Galactose. From this study it was apparent that the fermentation mechanisms for these hexoses was different from that of d‐Glucose. A Lineweaver‐Burke plot for the d‐Mannose and d‐Galactose data indicated that unlike Glucose these sugars do not follow the Monod kinetic model. As well, for the same initial sugar concentration the consumption of d‐Glucose was complete after 9 h, whereas for the other sugars 53% and 43% remained for d‐Mannose and d‐Galactose respectively after 9 h.