bluuebunny/crossref_metadata_2025 huggingface dataset:
Viscous effect on stagnation depth of bubbles in a vertically oscillating liquid column
Authors: Marmur Abraham , Rubin Eliezer
Published: March 2009

Previous 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

Relative 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

Gas‐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

An 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

The 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

An 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

A 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

The 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

An 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

The 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

Frequency 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

The 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

Preliminary 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 = xn

The 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

A 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

Mass 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

Research 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

The 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.
Model reference identification of state space models for a double effect evaporator
Authors: Chintapalli Prasad , Seborg Dale E. , Fisher D. Grant
Published: March 2009

A model reference identification technique is used to develop state space models of a double effect evaporator from experimental and simulated data. The model reference technique is based on a Liapunov design approach and is successfully used to estimate coefficient matrices containing 18 parameters in a third order model and 40 parameters in a fifth order model. However, in this application the success of the model reference technique required low measurement noise levels and a judicious choice of design parameters.
Interfacial turbulence accompanying chemical absorption
Authors: Sada E. , Kumazawa H. , Butt M. A. , Lozano J. E.
Published: March 2009

Absorption rates for carbon dioxide into aqueous solutions of EDA and MEA with and without adding surface active agent were measured in a laminar liquid‐jet apparatus to check and verify the Marangoni effect. In addition, experiments were conducted for the tracer desorption of ethylene from aqueous EDA and MEA solutions into carbon dioxide or nitrogen stream. It has been concluded that the Marangoni effect cannot be neglected for such short contact times as in a laminar liquid‐jet. The Marangoni instability accompanying the present chemical absorptions is attributed to combinated effects of the presence of ionic products, the depletion of the reactant liquid near the interface and an increase in interfacial temperature.
Kinetic parameters of isotopic exchange reaction in finite bath
Authors: Huang Ting‐Chia , Tsai Fuan‐Nan
Published: March 2009

A mathematical model has been proposed for an isotopic exchange reaction between the solid particles and ions in a solution of finite volume. A theoretical equation has been derived to predict the exchange fraction as a function of the dimensionless time T with the kinetic parameters ξ, ξ1 and final fractional uptake U as parameters for the exchange rate controlled by combined film diffusion, surface chemical reaction and intraparticle diffusion. The exchange fraction increases as the values of T, U, ξ and ξ, increase. Experimental results of the isotopic exchange systems CaCO3(s)Ca2+ (aq), CaC2O4(s)/ Ca2+ (aq) and Ca‐form Dowex 50W‐X8/Ca2+ (aq) agree well with the theoretical equation proposed in this study.
Kinetics of hydrogen reduction of nickel sulfide
Authors: Chida T. , Ford J. D.
Published: March 2009

The hydrogen reduction of powdered nickel sulfide (Ni3S2) at atmospheric pressure in the temperature range 475 to 630 °C has been experimentally investigated. The true intrinsic kinetics of this reaction were obtained, under conditions such that the topochemical shrinking core model in the chemical control regime could be applied. In the temperature range 475 to 530 °C, the rate constant could be expressed by the following equation:

Above 530°C, whisker formation of nickel metal was observed. It was also shown that the thermal history of the powder had an important bearing on the results obtained − in general, preheating led to lower reduction rates.
The effects of mixing, temperature, and nutrient concentration on the fermentation of a mixed sugar solution simulating the hexose content of waste sulfite liquor
Authors: Pineault G. , Pruden B. B. , Loutfi H.
Published: March 2009

The results of changes in temperature, mixing and nutrient concentration on the conversion by yeast of D‐mannose, D‐galactose, and D‐glucose using Saccharomyces cerevisiae strain were studied. These sugars are present in waste sulfite liquor. From the operating conditions used in this study, the most rapid removal of sugars found at a pH of 5 were temperature 36°C, mixing 700 rpm, and nutrient concentration 13.3 g/1. The fermentation was carried in a three‐litre batch reactor and the main variables measured were dissolved oxygen, yeast growth, alcohol production, total sugar consumption, and D‐mannose, D‐galactose and D‐glucose utilization. It was found that the fermentation could be fitted to the published Kono‐Assai model.
Étude de la déshydratation des ethers de glycol comme une nouvelle voie de synthèse des vinyl‐ethers
Authors: Salazar‐Tello J. C. , Lena L. , Phan‐Tan‐Luu R. , Metzger J.
Published: March 2009

A study has been made to determine the basic conditions to develop an economical manufacturing process for vinyl glycol ethers. To achieve the aforesaid purpose, the synthesis of the above‐mentioned products by means of glycol ether dehydration has been experimentally investigated; the most suitable way to achieve it has been found to be an indirect dehydration (pyrolysis of the corresponding acetates).

After having found the best way of synthetizing the vinyl glycol ethers, a determination has been made of the parameters which have a significant influence on the reaction carried out, in the gaseous phase, in a glass tubular reactor under normal pressure.

An optimization study has enabled to develop a model from which the maximum response area has been found, selectivity being the objective function.
Application of van't hoff's osmotic pressure equation to aqueous mixed electrolyte solutions
Authors: Tran Tuong‐Tu , Sangster James
Published: March 2009

An analogue of the compressibility factor for real gases has been applied to van't Hoff's osmotic pressure equation for aqueous solutions of single electrolytes. In addition, an analogue of Dalton's law for gas mixtures has been applied to mixed electrolyte solutions, which makes possible an estimation of the water activity (aw) of ternary solutions. The error in (aw) is approximately 0.1% for common‐ion systems (NaCl/KCl and NaNO3/Ca(NO3)2) and 0.5% for a system without common ions (KCl/NaNO3) at 25 °C.
Deposition of paraffin wax from kerosene in cooled heat exchanger tubes
Authors: Bott T. R. , Gudmundsson J. S.
Published: March 2009

Studies of the deposition of wax from wax/kerosene mixtures onto cooled simulated heat transfer tubes has demonstrated that, following an initial deposition taking a relatively short period of time, the heat transfer resistance fluctuates with time.

Theoretical estimates of temperature distribution in the experimental flowing wax/kerosene system suggest that the cloud point temperature of the mixture falls within the laminar boundary layer. Since the cloud point is considered the temperature at which particles of wax appear, the conditions within the boundary layer will influence deposition. Increased flowrate and temperature decrease the number of particles able to deposit while the number is increased by greater wax concentration in the bulk solution.
Hydrodynamic particle volume and fluidized bed expansion
Authors: Fouda A. E. , Capes C. E.
Published: March 2009

Particulate fluidized bed expansion may be described by the Richardson‐Zaki equation,\documentclass[article]\pagestyle[empty]\begin[document]$ \frac[u][[u_i ]] = e^n $\end[document] The values of n for very fine and/or aggregated particles and for particles of irregular shape are often found to be larger than those for comparable spherical particles. Previous work on aggregated systems by one of the authors showed that a modified Richardson‐Zaki equation, \documentclass[article]\pagestyle[empty]\begin[document]$ \frac[u][[u_i ]] = \left( [1 - KC] \right)^n $\end[document] (where C = 1‐ε), provided a more consistent correlation of the data. The parameter K accounted for the effective hydrodynamic volume of the particles during fluidization and the application of this concept to non‐spherical particles was the subject of the present study. While K for spherical particles was essentially equal to unity, values from 1.17 to 1.43 were found for equidimensional but irregular particles with considerably higher values for flat particles. An equation relating K to particle shape is offered which, when combined with the Richardson‐Zaki relationships, provides a more accurate prediction of the expansion behaviour of non‐spherical particles.
A model for particle collection with potential flow between two parallel cylinders
Authors: Choudhary K. R. , Gentry J. W.
Published: March 2009

A Model for predicting the collection efficiency of two parallel cylinders was developed for the case when the velocity field between the cylinders can be approximated by potential flow. The model uses the method of images.

The efficiencies predicted from this model were compared with calculations for potential and viscous flow about a single cylinder as well as with the Harrop and Stenhouse model. The theory was compared with experiments by Fan.
Fluid‐particle hydrodynamics in agitated vessels
Authors: Ambegaonkar Anil S. , Dhruv Ashok S. , Tavlarides Lawrence L.
Published: March 2009

A two dimensional model is proposed to predict mean radial and axial velocities for turbulently agitated fluids in baffled tanks with a turbine impeller.

A particle dynamics model that simulates the movement of dipsersed phase particles in turbulent dispersion by a statistical Monte Carlo technique is coupled with this fluid dynamics model. The comparison of the flow directions, radial and axial velocity profiles, and the volumetric discharge capacities of the turbine impeller with the experimental data is favorable.
A simple three‐parameter equation of state with critical compressibility‐factor correlation
Authors: Horvath Csaba , Lin Hung‐Jye
Published: March 2009

A three‐parameter equation of state is proposed for fluids whose critical compressibility factor is not greater than 0.275. The equation is third order in volume and its constants are evaluated from the critical temperature and pressure as well as from the premultipliers that are interrelated and dependent on the reduced limiting volume of the fluid. The premultipliers have been evaluated from a single compressibility‐factor correlation extrinsically. The proposed equation is as easy to handle mathematically as the Redlich‐Kwong equation and yields analytical expressions for various fluid properties. The results show, however, that it represents the properties of normal and polar fluids much more accurately, particularly in the saturated vapor and the liquid region.
Startup of a pipeline containing settled solid particles
Authors: Peters J. , Salazar A. , Shook C. A.
Published: March 2009

Experimental studies have shown that, provided a threshold velocity is exceeded, bed of solid particles can be displaced from pipelines at low pressure gradients using fluid velocities near the limit‐deposit velocity. The time scale of the process depends upon three factors: fluid acceleration, bed erosion and displacement. Results are reported for water slurries of a silica send of d50 = 0.43 mm. A simple model for the transient response is proposed.
The effect of some alkaline additives on the viscosity of coal water slurries
Authors: Shook C. A. , Nurkowski J.
Published: March 2009

The viscosity‐reducing effects of various alkaline additives to coal slurries were studied. It was found that especially in combination with leonardite, a naturally oxidized form of lignite, significant reductions could be achieved for a bituminous and a sub‐bituminous coal. No reduction could be produced for lignite slurries, however.
Inclined hot‐wire response equations for a flow field having a dominant tangential velocity component
Authors: Bank Nader , Gauvin W. H.
Published: March 2009

Modified sets of response equations have been derived for a single inclined hot‐wire probe introduced in various orientations in a flow field having a dominant tangential velocity component. By means of these equations, the components of the three dimensional mean velocity vectors, the turbulence intensity and the Reynolds stresses can be easily determined at any location in a swirling flow which is stationary with time. This method is particularly applicable to the characterization of the flow field in chemical processing equipment where this type of swirling flow is increasingly being used. It has been successfully applied to a study of the flow field in a spray‐drying chamber, in the course of which good reproducibility and consistency of results were obtained.
Enhancement of liquid extraction by an instantaneous, irreversible reaction
Authors: Miller Joseph W. , Harper Dean O.
Published: March 2009

A quasi‐steady state analysis was applied to the enhancement of liquid extraction by a chemical reaction. Ethylene glycol drops were allowed to fall through a stationary heptane phase containing iodine (component A) in a 2.42 cm I.D. column operated at varying heights. The overall mass transfer coefficient, after elimination of end effects, for iodine from heptane into the glycol drops was determined to be K° = 0.213 mol/(s.m.2).

By the addition of sodium thiosulfate (component B, Na2S2O3) to the inlet glycol, an instantaneous and irreversible reaction

I2 + 2Na2S2O3 → Na2S4O6 + 2NaI

took place in the glycol phase, increasing the value of K to a maximum value of 0.5 mol/(s.m2).
Compensation effect and its use in catalyst correlations
Authors: Ranganathan R. , Bakhshi N. N. , Mathews J. F.
Published: March 2009

Catalysts of varying surface properties (e.g. surface area, pore volume and crystallite size) and of varying bulk properties (e.g. metallic radius, heat of formation of oxide and percentage d‐character) were evaluated as catalysts for the decomposition of hydrogen peroxide. Surface properties were varied by studying the following catalysts: unsupported nickel oxide, nickel oxide/α‐alumina, nickel oxide/α‐alumina and nickel oxide/silica‐alumina. The bulk properties were varied by studying the oxide catalysts of different metals such as nickel, chromium, mangenese, cobalt and palladium. The results obtained from this work along with the data obtained from a search of the literature, were correlated using a compensation plot (linear relationship between the activation energy and the logarithm of the frequency factor). General correlations for bulk properties and catalytic activities are presented for the decomposition of hydrogen peroxide. The use of a “Compensation Effect” for the hydrogenation of ethylene is also discussed.
The effect of flow regime on the continuous emulsion polymerization of styrene in a tubular reactor
Authors: Rollin A. L. , Patterson I. , Bataille P. , Huneault R.
Published: March 2009

Five isothermal emulsion polymerizations of styrene in a tubular reactor were studied experimentally using an emulsifier concentration in the vicinity of the critical micelle concentration (CMC). The flow regime was characterized by an emulsion Reynolds Number (NRe)e calculated using the emulsion properties prior to any appreciable reaction.

It was found that the rate of polymerization was a maximum at the laminar‐turbulent transition based on (NRe)e. This behavior is similar to emulsion polymerizations carried out in batch reactors where a maximum rate of polymerization has been observed when the agitation level (agitator rotation rate) is varied. The controlling mechanisms appear to be similar at high agitation levels but differ when the emulsion is weakly agitated.
Processing athabasca tar sands — tailings disposal
Authors: Camp Frederick W.
Published: March 2009

Public awareness and concern over the tailings disposal aspects of tar sand development are increasing. This paper describes why the hot water extraction process can lead to an accumulation of tailings sludge. A theory is proposed to predict tailings accumulation rate; predictions are compared with GCOS' operating experience. Using this theory, future projects can be evaluated on their merits without extrapolating GCOS' experience, which may or may not be applicable. Several unsuccessful approaches to reducing sludge accumulation are described to encourage others to seek new approaches.
A study of phosphate hide‐out from boiling water
Authors: Balakrishnan P. V.
Published: March 2009

Sodium phosphates deposit on heat transfer surfaces from boiling solutions. This process of deposition, which is termed “hide‐out”, was studied in a recirculating loop operating at the temperature and pressure of the secondary system in CANDU‐PHW* steam generators. The relation between the compositions of the deposit and solution, is in agreement with studies by others. An additional depletion of phosphate was found, which probably related to reaction with corrosion product deposits on the loop surfaces. The observations from this study suggested a maximum desirable range for Na/PO4 molar ratio in solution of 2.2 to 2.6 for phosphate treatment of steam generator water.

Lithium phosphate treatment is unsuitable because it forms hard scales and also causes accelerated corrosion of boiler tubing.
The analysis and design of binary vapour‐liquid equilibrium experiments. Part II: The design of experiments
Authors: Sutton Thomas L. , Macgregor John F.
Published: March 2009

Statistical theory on the optimal design of experiments is used to demonstrate how one might design binary vapour‐liquid equilibrium experiments to yield the greatest amount of information on the unknown parameters in semi‐empirical thermodynamic models. The design of an isothermal or isobaric equilibrium experiment is considered to involve the choice of the liquid phase composition at which the experiment should be performed. Examples are used to illustrate how these procedures can be used to select experimental regions which would yield the most information on the parameters and to reveal other regions in which very little information would be obtained.
Guidelines for the optimal design of experiments to estimate parameters in first order kinetic models
Authors: Reilly Park M. , Bajramovic R. , Blau G. E. , Branson D. R. , Sauerhoff M. W.
Published: March 2009

The optimal designs for experiments to estimate velocity and equilibrium constants in first order chemical kinetic situations are examined. Equations and charts which choose optimal designs are presented. A bioconcentration test using fish as the test organism is used to illustrate the problem and some good experiments of this type performed in the past are compared for efficiency with the corresponding optimal ones. Examples are also given of the statistical analysis of this type of experiment.
Effect of orifice shape on air atomized water spray characteristics
Authors: Beeckmans J. M. , Chan E. W.
Published: March 2009

A study has been made of the dispersion characteristics of air atomized water sprays from injection orifices oriented normally to the air flow in a duct. Circular sectioned and rectangular sectioned orifices were employed, for both parallel and perpendicular orientation of the longest dimension of the rectangular orifices, with respect to the air flow direction. Rectangular orifices were found to produce more widely dispersed sprays than circular arifices of approximately equal cross‐sectional area, under otherwise identical conditions. The reasons for these observations are not understood; further studies on droplet size distributions and other factors are indicated.
Rheological comparison of three polyethylene film resins
Authors: Dealy John M. , Garcia‐Rejón Andrés , Kamal Musa R.
Published: March 2009

Several rheological tests have been carried out on low density, film‐grade polyethylenes manufactured by three Canadian companies. The resins all have densities around 0.92, but are made by different processes. The Union Carbide resin is made in a tubular reactor, the C.I.L. resin in a two‐stage autoclave and the DuPont of Canada resin by means of a low pressure copolymerization process.

The shear viscosity was determined for each resin over a wide range of shear rates at several temperatures, and the first normal stress difference was determined at low shear rates. Die swell was measured at the higher shear rates. The low‐pressure copolymer was found to be quite similar in its behavior to the resin made in a high pressure autoclave.

Correlations between the various properties measured, proposed by Abdel‐Khalik et al(7) on the basis of the Goddard‐Miller constitutive equation(8), were tested and found not to be obeyed. A method proposed by Tanner for calculating die swell from the viscometric functions is also evaluated.
A three‐parameter markov model for sedimentation
Authors: Tory E. M. , Pickard D. K.
Published: March 2009

Considering velocity perturbations as white noise and assuming exponential decay of velocities to the mean velocity μ, we obtain a two‐parameter Langevin equation. The conditional and steady‐state probability density functions for instantaneous velocity are used to develop theoretical expressions for variables which can be measured experimentally. Support for the model is adduced from published data and our own experimental results. The parameter μ is obtained from the mean of the distance travelled in time T during steady state and the two Langevin parameters from its correlation coefficient and variance. Precision and bias in experimentation are discussed.
Freezing of liquids in turbulent flow inside tubes
Authors: Shibani Ali A. , Özisik M. N.
Published: March 2009

The problem of steady‐state freezing of liquids in turbulent flow inside a tube with its walls kept at a uniform temperature lower than the freezing temperature of the liquid is solved for a wide range of Reynolds and Prandtl numbers, 104 ≤ Re ≤ 104 and 0 ≤ Pr ≤ 103. The effects of Prandtl and Reynolds number on the location of the solid‐liquid interface and on the heat transfer rate as a function of position along the tube are established.
On the representation of liquid properties of pure polar compounds by means of a modified redlich‐kwong equation of state
Authors: Chung W. K. , Lu Benjamin C.‐Y.
Published: March 2009

The temperature‐dependent parameters ωa and ωb of the Redlich‐Kwong equation of state were evaluated from saturated liquid volumes and vapor pressures for three polar compounds, water, ammonia and sulfur dioxide, and then correlated in terms of Tr. To demonstrate the applicability of the resulting correlation, the values of ωa and ωb computed from these equations were used to evaluate the liquid properties of these compounds, such as vapor pressures and liquid volumes at saturation, and the heat of vaporization at the normal boiling point. In addition, the enthalpy departures of liquid water as well as the liquid volumes of compressed water were calculated. The results obtained from the proposed correlations are generally superior than those obtained from the equations of state recently proposed by Fuller, and Peng and Robinson.
The measurement and prediction of the solubility of acid gases in monoethanolamine solutions at low partial pressures
Authors: Nasir Pervaiz , Mather Alan E.
Published: March 2009

An apparatus for the determination of the solubility of hydrogen sulphide, carbon dioxide and their mixtures in ethanolamine solutions at low pressures is described. With this apparatus, the solubility of H2S, CO2 and their mixtures in aqueous solutions of monoethanolamine has been measured at partial pressures between 0.001 kPa and 9 kPa at temperatures of 80° and 100°C. The results for the mixture have been compared with two methods of prediction based on a thermodynamic model.
Joule‐Thomson effects on turbulent graetz problem for gas flows in pipes with uniform wall temperature
Authors: Cheng K. C. , Ou Jenn‐Wuu
Published: March 2009

The Joule‐Thomson effect is known to be important in arctic gas pipelines. The Joule‐Thomson effects on forced convective heat transfer in the thermal entrance region of pipes with uniform wall temperature are studied for steady fully developed turbulent gas flows by the Graetz method. Thermal entrance heat transfer results are presented for Prandtl number 0.72, Reynolds number 105 and Brinkman number ± 0.1, ± 1.0 with Joule‐Thomson parameter Jμ ranging from 0 to 1.0 to cover the possible range in practical applications. Bulk temperatures and Nusselt numbers are also presented for fully developed flow with Reynolds numbers from 5 × 103 to 106. For given Prandtl and Reynolds numbers, the asymptotic Nusselt number is found to be dependent on the Joule‐Thomson parameter only and is independent of Brinkman number. The fully developed bulk temperature is a linear function of Brinkman number and a linear relationship exists between the bulk temperature parameter (‐θbf/Br) and the Joule‐Thomson parameter Jμ for given Prandtl and Reynolds numbers.
Co‐current flow liquid‐liquid binary mass transfer in ejectors
Authors: Acharjee D. K. , Mitra A. K. , Roy A. N.
Published: March 2009

Liquid‐liquid binary mass transfer involving simultaneous transfer of an organic phase component to the aqueous phase and an aqueous phase component to the organic phase in water‐n butanol and water‐methyl ethyl ketone systems has been studied in a vertical ejector system. Correlations have been developed to predict both dispersed and continuous phase film capacity coefficients as function of various physical and dynamic variables of the system.
Catalytic oxidation of benzene to maleic anhydride in a continuous stirred tank reactor
Authors: Quach T. Q. Phung , Rouleau D. , Chavarie C. , Laguerie C.
Published: March 2009

The kinetics of the vapor phase oxidation of benzene has been studied over an industrial catalyst in a continuous stirred tank reactor in the temperature range from 280 to 430°C and at atmospheric pressure. The products obtained are maleic anhydride, carbon oxides and water. The rate of the overall reaction (disappearance of benzene) is represented by the following expression based upon a steady state adsorption model

The rate of formation of maleic anhydride is correlated by the equation

which allows for a homogeneous depletion of maleic anhydride. The rate constants kB, kO, k2(g) were found to follow Arrhenius behavior.
Use of waste liquor from bisulfite pulping to produce mixed culture single‐cell protein
Authors: Lo S. N. , Moreau J. R. , St‐Laurent G.
Published: March 2009

The activated sludge process might be used in the very near future to treat the waste liquors from small bisulfite mills in Canada, as a mean of controlling water pollution. These mills produce normally less than 300 t/d of pulp. It was found that the bio‐sludge solids from such a process, when used to treat such waste liquor, contained approximately 38% protein, 47% carbohydrates, some vitamins and sufficient quantities of essential minerals. This bio‐substance, a mixed‐culture in nature, could be considered as a good source of single‐cell protein. The nutritive value in terms of protein efficiency ratio of this substance was tested with rats; good results were obtained when the biomass was slightly supplemented with methionine.

Described in this paper is a system used in our laboratory to produce this biomass in a sterile and dried form. The conversion of carbohydrates contained in waste pulping liquor to biomass was carried out in a 400‐l, aerated, continuous‐flow tank reactor. Under the operating conditions studied the sludge yield coefficient was 0.53 g of biomass/g of carbohydrates removed. A cash return study of selling biomass is also presented for two mills producing high‐ and low‐yield pulps respectively.
Hydrodynamics and mass transport in rotary disk contactors
Authors: Laddha G. S. , Degaleesan T. E. , Kannappan R.
Published: March 2009

This paper reports a detailed study of the hydrodynamics involved in the operation of rotary disk contactors (RDC). New information is presented regarding the ‘critical rotor speed’ which divides the two hydrodynamic regimes of near constant and varying characteristic velocity of the dispersed droplet phase. Generalized correlations for prediction of characteristic velocity both above and below the critical rotor speed have been proposed under conditions of no solute transfer as well as solute transfer between the dispersed and continuous phases. Experimental data on mass transfer obtained in the two hydrodynamic regimes of RDC operation have also been correlated by the application of mass transport theory taking into account the factors affecting the interfacial area of contact, drop size, characteristic velocity and dispersed phase holdup.
Two‐phase laminar zero net flow in a circular inclined pipe
Authors: Masliyah Jacob H. , Shook C. A.
Published: March 2009

Steady countercurrent zero net flow of two immiscible fluids in an inclined circular tube has been studied under laminar flow conditions. Using appropriate dimensionalization, the interface position and viscosity ratio become the only two parameters that govern the flow. Velocity profiles and shear stresses were determined from numerical solutions of the equations of motion and are compared with the analytical solutions for flow between parallel plates. Such zero net flows are encountered at shutdown of long inclined slurry pipelines. The results of the present investigation are suitable for modelling these flows.
Laminar flow between a circular tube and a cylindrical eccentric capsule
Authors: Garner R. G. , Raithby G. D.
Published: March 2009

The fully‐developed laminar flow between a circular tube and an eccentric moving cylindrical rod is predicted for eccentricities between zero and unity. For eccentricities less than unity, an earlier solution is extended to account for arbitrary rod (capsule) velocities; useful shear force expression in closed form are given. An entirely new solution for the fully eccentric case is presented.
Batch adsorption for pore diffusion with film resistance and an irreversible isotherm
Authors: Weber Thomas W.
Published: March 2009

Equations are developed for finite‐batch, irreversible adsorption where both pore diffusion and film resistance are significant. Quasi‐steady state behavior is assumed and comparisons are made for sheets, cylinders, and spheres. The equations for the three shapes are generalized to a single form. For equal volumes of adsorbent, when the external film controls, spheres attain equilibrium more quickly than cylinders, and cylinders more quickly than sheets. When internal diffusion controls and the ratio of the final to the initial solution concentration is high, this ordering of equilibrium times is preserved; however, if the ratio is very low, the ordering is reversed.
Gas separation by permeation Part I. Calculation methods and parametric analysis
Authors: Pan C.‐Y. , Habgood H. W.
Published: March 2009

Calculation methods for single‐ and multi‐stage permeation of a multi‐component mixture are presented. The use of the local permeate concentration in the formulation results in a relatively simple form of solution for the binary system in the cross‐flow pattern. A parametric analysis of the permeation cascade is given. For a given permeability of the more permeable component, there exists a membrane selectivity which gives rise to a minimum membrane area requirement in the cascade. It is shown that the compression power requirement is dependent only on the operating pressure ratios, irrespective of actual pressure levels in each stage. A study on the effect of interstage mixing loss shows that the ideal cascade (with no interstage mixing loss) is not necessarily always the thermodynamically most efficient one; some non‐ideal cascades may have higher efficiencies due to more effective permeation steps. Examples given relate to He/CH4 and O2/N2 separations.
Vapor phase oxidation of p‐xylene
Authors: Mathur B. C. , Viswanath D. S.
Published: March 2009

The kinetics of the vapor phase oxidation of p‐xylene over ferric molybdate catalyst were studied in an isothermal, differential, tubular flow reactor in the temperature range of 360 to 420° C. The major product obtained was p‐tolualdehyde with small amounts of maleic anhydride and p‐toluic acid. No terephthalic acid or CO2 were observed.

The reaction rate data collected fit the redox model given by Equation 1. The values of activation energies Ex, Eo and frequency factors Ax, Ao obtained are 72, 63 kJ/mol and 0.64, 2.89 m3/kg catalyst s respectively.

The reaction mechanism was established by studying the oxidation of p‐tolualdehyde, toluic and terephthalic acids. It is concluded that the reaction follows a parallel‐consecutive scheme.
Cristallisation du trihydrate d'alumine: Un modèle pour l'attrition
Authors: Remillard Michel , Cloutier Leonce , Methot J.‐Claude
Published: March 2009

L'attrition des cristaux de trihydrate d'alumine a été étudiée dans un réacteur isotherme parfaitement agité en régime discontinu. Des essais expérimentaux ont été réalisés en utilisant des particules tamisées. La granulométrie des cristaux a été mesurée afin de suivre l'évolution du nombre de particules en fonction du temps d'opération. Les résultats expérimentaux ont servi à développer un modèle mathématique permettant de représenter le phénomène d'attrition. Ces données nouvelles pourront par la suite ětre exploitées dans l'industrie de l'aluminium en vue de simuler les cristalliseurs industriels.
Sodium‐sulphur cells
Authors: Foulkes F. R. , Choi P. T.
Published: March 2009

The sodium‐sulphur battery is reviewed and experimental results are presented. The experimental cells were capable of delivering steady state power densities as high as 50 W.kg−1and energy densities as high as 250 W.h.kg−1. The theoretical open circuit voltage of 2.08 V was observed in all cases. Cell polarization was limited by cell internal resistance, which was attributed largely to the resistance of the β‐alumina electrolyte. The “asymmetry effect” is explained in terms of an electrode blockage mechanism involving polysulphides. The sodium‐sulphur battery appears to be technically feasible as the power source for an all‐electric vehicle.