bluuebunny/crossref_metadata_2025 huggingface dataset:
A dynamic theory of mass transfer at a wavy interface
Authors: Rice Richard G.
Published: March 2009

A new theory to predict mass transfer at an interface undergoing stationary oscillations is presented. The theory describes mass transfer when a slightly soluble gas is dissolving in a dynamic liquid interface. It is shown that mass transfer under these conditions is a function of the square of wave amplitude, and depends, in a complex way, on a characteristic Schmidt and Reynolds number. The latter quantities are defined in terms of the characteristic wave‐length and frequency of the system periodicity. In the limit of large Reynolds and Schmidt numbers, which characterize most real liquid‐gas systems, the theory takes a particularly simple form and shows that the ratio of the mass fluxes for dynamic to stagnant interfaces is independent of Schmidt number and depends only on the square of the amplitude‐wave length ratio and the square root of the Reynolds number. Using the Kapitsa hydrodynamic parameters, the mass transfer theory is compared with data from a wetted‐wall column.
Application de l'équation de Wilson à l'estimation des enthalpies de mélange
Authors: Duran J. L. , Kaliaguine S.
Published: March 2009

On montre que l'équation de Wilson peut représenter simultanément les enthalpies libres d'excès et les enthalpies de mélange des systèmes binaires totalement miscibles. Les coefficients, dépendant de la température, sont calculés à partir des données binaires et permettent un calcul simple et précis des enthalpies des mélanges à plusieurs composants.
Compressibilities of helium‐nitrogen mixtures
Authors: Mathews J. F. , Morey D. C. D.
Published: March 2009

The compressibility factors of nitrogen, helium and three mixtures were determined at 310.93, 338.71, 366.48, 394.26, 422.04, and 449.82°K. over a pressure range from 100–5000 psia. using a variable volume‐constant mass apparatus. Values of Z are tabulated versus the experimental values of pressure. Compressibility factors were correlated using the virial and Redlich‐Kwong equations of state.
A correlation for the solubility of hydrocarbons in water
Authors: Leinonen P. J. , Mackay D. , Phillips C. R.
Published: March 2009

A correlation has been developed for the solubility of C4 to C10 hydrocarbons in water at 25°C and atmospheric pressure. The excess Gibbs free energy is correlated in terms of an effective molar volume which is related to the actual molar volume adjusted to include the effects of the degree of branching, the number of olefinic and acetylenic bonds and the number of aromatic and cycloalkane rings. The root mean square deviation between 59 correlated and experimental solubilities is 20%. The range of solubilities is from 0.052 to 5150 g hydrocarbon per 106 g water. The correlation provides a rational procedure for the estimation of solubility of other hydrocarbons.
A turbulent transport model with emphasis on heat transfer to liquid metals
Authors: Thomas Lindon C.
Published: March 2009

An analysis of the energy transport to eddies in transit from the turbulent core to the wall region coupled with the elementary surface renewal and penetration model is presented for the turbulent tube flow of liquid metals. Previous formulations of the various forms of the surface renewal and penetration model have been based on the assumption that eddies arrive at the surface with initial temperature T1 equal to the bulk stream temperature Tb. However, due to the significance of molecular transport during the flight of eddies from the turbulent core to the wall region, the employment of this assumption immediately restricts the model to the analysis of the mean heat flux for fluids other than liquid metals. In contrast, the present analysis gives rise to an expression for the mean Nusselt number for turbulent tube flow which is shown to be applicable to fluids with moderate values of the Prandtl number (Pr = 0.5 ‐ 5.0) as well as to the flow of liquid metals at high values of the Reynolds number.
An analysis of heat transfer during flow of an air/water mist across a heated cylinder
Authors: Finlay I. C.
Published: March 2009

Equations are developed for predicting local heat‐transfer coefficients over the forward‐facing half of a cylinder during transverse, mist flow. At low approach velocities predicted values are found to be in good agreement with corresponding measured values. With increase in approach velocity, agreement is found to fall off owing largely to the onset of a severe splashing or bouncing action. This effect is examined, together with effects of evaporation and convection at the free surface of the liquid layer formed on the cylinder.
A selectivity method for modelling the kinetics of pentene‐2 hydrogenation
Authors: Rao M. S. , Hudgins R. R. , Reilly P. M. , Silveston P. L.
Published: March 2009

A maximum likelihood ratio was used as a statistical criterion for discriminating among twenty‐two kinetic models posited to describe the hydrogenation of mixed pentenes (cis‐ and trans‐2‐pentenes) with a Raney nickel catalyst. Selectivity ratio, the ratio of reaction rates of two different species, was used and found to be a suitable extension of conventional techniques for identifying rate controlling steps owing in this case to its reproducibility. Selectivity ratio models were of the Langmuir‐Hinshelwood form.

Hydrogenation was performed isothermally at 20°C in benzene at five constant pressures corresponding to partial pressures of hydrogen of 22.5, 42.3, 62.3, 112.3 and 122.1 psia.

Discrimination was attempted at each pressure, but found acceptable only at the three intermediate pressures. At each of these pressures, a model of similar functional form was found to represent the selectivity data; however, this model appears to be empirical.

The likelihood ratio approach appears to be a powerful one for discriminating among a large number of models even with only a moderate number (˜ 20) of experimental observations.
White's method of thermodynamic calculations applied to ammoxidation of propylene
Authors: Suryanarayana K. , Reddy P. J. , Murti P. S.
Published: March 2009

A method of steepest descent first applied by White et al. to the calculation of complex chemical equilibrium was used in this article to compute the equilibrium composition of a mixture resulting in the ammoxidation of propylene. As many as twenty species are likely to be present, some in insignificant quantities. A FORTRAN II Program was written for an IBM 1620 computer and calculations were made varying the feed composition, temperature and pressure. The results were discussed and qualitatively compared with those of the plant practice reported in the literature. The agreement is reasonably good when the oxygenated compounds are excluded from consideration.
Fluid velocity profiles near the wall of liquid‐fluidized beds
Authors: Allen B. G. , Smith J. W.
Published: March 2009

A direct, non‐disturbing flash photolysis dye technique has been used to measure liquid velocities in 2.465‐in. beds of 0.1248, 0.233 and 0.368‐in. diameter lucite spheres at porosities of 0.8 and 0.9. Aggregative fluidization, including layering, was observed in all beds, and increased in magnitude with the larger spheres. Distinct velocity maxima were found from 0.5 to 2 particle diameters from the wall and distinct minima at from 0.6 to 1.2 particle diameters for the more particulately fluidized beds. Variations in velocity greater than the mean were observed.

Conservatively estimated wall shear stresses were 2 to 5 times times larger than in the open pipe.
The separation of micron‐size particles from air by diffusiophoresis
Authors: Meisen A. , Bobkowicz A. J. , Cooke N. E. , Farkas E. J.
Published: March 2009

The continuous separation of micron‐size particles from air by diffusiophoresis in a parallel plate collector was studied theoretically. Two models for the particle behavior were considered. Model I was based on the assumption that the particles adopt the local fluid velocity whereas the Schmitt‐Waldmann equation was used to determine the diffusiophoretic velocity in Model II. The latter also included thermophoretic and gravitational effects.

The two models yielded similar results when diffusiophoresis was predominant. The theoretical results were also used in the sizing of an experimental particle collector. The collector, which operated under laminar flow conditions, was capable of removing the particles effectively and its performance conformed with the theoretical work.
Laminar film boiling on a porous vertical wall with uniform suction velocity
Authors: Krishnamurthy M. V. , Ramachandran A.
Published: March 2009

Laminar free convection film boiling on a porous vertical wall with uniform suction or blowing is analysed using boundary layer theory. The solutions are obtained assuming suction or blowing to be a disturbance superposed on the isothermal, impermeable wall case. Using a parameter involving the suction or blowing velocity, universal functions are derived for various values of Prandtl Number and cp(Tw — Tsat)/hfgPr. These universal functions can be used to estimate the heat transfer rate in the presence of suction or blowing. As expected, suction increases the heat transfer rate while blowing decreases the heat‐transfer. Even small velocities of suction or blowing could significantly affect the heat transfer. It is also found that the effects of suction or blowing are more pronounced at lower wall superheats.
Heat and mass transfer in spouted beds ‐ A review
Authors: Epstein Norman , Mathur Kishan B.
Published: March 2009

The considerable literature on spouting which has accumulated since the inception of this fluid‐solid contacting technique fifteen years ago is critically reviewed with reference to heat and mass transfer. The relatively meagre basic data on both surface‐to‐bed and fluid‐to‐particle heat transfer, as well as particle‐to‐fluid mass transfer, are interpreted wherever possible, in the light of understanding gained from more exhaustive information available on the hydrodynamics of the system. Contradicitions are noted and in some cases reconciled. Conclusions are drawn as to the relative merits of various correlations.

Design equations for heating or cooling of solids for both batch and continuous systems are formulated and a new theoretical model to describe wall‐to‐bed heat transfer is proposed.
Coupled transport of heat and mass in laminar tube flow
Authors: Chen T. S. , Scheffel G. A. , Huang L. M.
Published: March 2009

An analysis is performed of the mutually dependent heat and mass transfer for gas flow in a circular tube. Sublimation occurs at the inner surface of the wall, while the outer surface is thermally insulated from the external environment. The flow is assumed to be laminar and hydrodynamically fully developed. Mathematical expressions are derived and numerical results are given for bulk temperature and bulk mass fraction, wall temperature and wall mass fraction, wall heat and mass fluxes, local Nusselt number, temperature and mass fraction profiles, and length of the development region. Comparisons are made of the results based on a parabolic velocity profile with those based on a slug flow profile.
L'effet du molybdène sur l'oxydation partielle du méthane par l'oxygène‐pur
Authors: Blanchard L. P. , Yim Yoeun
Published: March 2009

L'influence du molybdène sur l'oxydation partielle du méthane par l'oxygène pur a été étudiée pour trouver les conditions menant à sa conversion complète en gaz de synthèse, sans excès d'oxygène ni formation de gaz carbonique, de vapeur d'eau ou de dépǒts de carbone. La carburation du molybdène par le méthane et sa décarburation par l'oxygène expliqueraient que seuls deux produits, le monoxyde de carbone et l'hydrogène, sont trouvés dans les gaz de sortie. La composition de ces gaz à l'équilibre a été calculée à partir de données thermodynamiques pour les étapes retenues et ce, pour toutes les conditions prévues d'opération. Soixante essais ont ensuite été faits pour vérifier ces compositions, en variant la température de 1200 a 1900°K, le poids de molybdène de 0 à 5 grammes, le rapport méthane‐oxygène de 1.6 à 2.2 et la vitesse spatiale horaire de 50 à 250. Au‐delà de 1600°K, les mélanges stoéchiométriques de méthane et d'oxygène en présence de molybdène ne donnent, en général, que du monoxyde de carbone et de l'hydrogène dans le rapport 1 à 2. L'analyse, par diffraction des rayons‐X, de la phase solide renfermant le molybdène, démontre la présence de carbure de molybdène, ce qui confirme le rǒle intermédiaire assigné au molybdène dans l'oxydation partielle du méthane par l'oxygène pur.
Influence du molybdène sur la cinétique des réactions de conversion du méthane en présence de H2O et CO2
Authors: Vanderschuren J. , Kaliaguine S.
Published: March 2009

Une étude expérimentale de l'action catalytique du molybdène sur les réactions de conversion du méthane en gaz de synthèse par la vapeur d'eau et le gaz carbonique a été faite dans un réacteur différentiel à lit fluidisé.

Les essais ont été réalisés de façon à limiter les réactions homogènes susceptibles de masquer l'effet catalytique.

On montre l'importance de l'influence du rapport O2/CH4 de l'alimentation et des réactions hétérogènes d'oxydation du métal ou de formation du carbure Mo2C, sur les rendements.

A partir des résultats cinétiques obtenus en présence du carbure et du métal pur, on propose un mécanisme réactionnel, et on présente une équation de vitesse pour la réaction de conversion du méthane par la vapeur d'eau sur le molybdène.
Improved parametric characterization of flow geometries
Authors: Kozicki William , Tiu Carlos
Published: March 2009

An improved parametric method is presented for characterization of the flow geometry in the rectilinear flow of non‐Newtonian fluids in open and closed conduits of arbitrary crosssection and in purely viscous, inelastic flow of non‐Newtonian fluids through packed beds and porous media. In the new formulation, an infinite number of geometric parameters characterize the flow geometry. The actual number required in a particular application is shown to be determined by the fluid model equation representing the rheological behavior of the fluid. For Ostwald‐de‐Waele and Ellis fluids with flow behavior indices s = 1/n and α integers, the number of geometric parameters required to represent the relationship between flow rate and pressure drop is given by s + 1 and α + 1, respectively. The efficacy of the present method is demonstrated by comparisons with available results for various fluid models and flow geometries.
Experimental heat capacities of carbon dioxide‐methane mixtures at elevated pressures
Authors: Bishnoi P. R. , Robinson D. B.
Published: March 2009

The heat exchanger method of determining the ratio of heat capacity at a pressure to the heat capacity at a low pressure was used to obtain data on two binary mixtures of methane and carbon dioxide containing 14.49 and 42.30 mole % methane. The data were obtained at pressures up to 2,250 psi in the temperature range of ambient to 150°C and are expected to be accurate within ± 0.5 % in the regions removed from the pressure maxima and within ± 1 % in regions close to the maxima. Heat capacities of the two binary mixtures were calculated using the BWR equation of state, the generalized correlations of Curl and Pitzer and Yen and Alexander, and the method of Orentlicher and Prausnitz. The calculated values were compared with the experimental values.
Temperature coefficient of gas solubility for regular solutions
Authors: Hayduk W. , Buckley W. D.
Published: March 2009

A semi‐empirical method is reported for predicting the temperature coefficient of gas solubility for regular solutions. It appears to be capable of describing the temperature coefficient to an accuracy approaching that of the solubility measurements themselves. The method requires a knowledge of the solvent solubility parameter and critical temperature, as well as at least one solubility (at any temperature) of the gas in the particular solvent. New data for the solubilities of methane in hexane, heptane, octane, dodecane and hexadecane, over the temperature range (where possible) from O°C to 75°C along with a large number of previously published data are used to show the effectiveness of the proposed method.
Trays for gas‐liquid contacting
Authors: Kilgallon J. D. , Furter W. F.
Published: March 2009

A type of tray for gas‐liquid contacting is described, in which the free area for gas flow through the tray is variable with and controlled by the gas flowrate. The property through which control of the free area is effected is the surface tension of the liquid phase. The advantages are the same as those of ballast and valve trays; namely, reduced pressure drop at high gas rates resulting in increased column capacity, and reduced free space at lower gas rates resulting in high mass transfer efficiency at low and medium vapor loadings as well. Tooling and production costs for the trays of the present investigation, however, are considerably lower than for ballast or valve trays or any other types which require machining operations in their fabrication, and are as low or lower than for sieve trays. Initial experimental comparisons with conventional trays demonstrated that the trays of the present investigation, although designed primarily for operation at high vapor loadings, were indeed capable of yielding high mass transfer efficiencies in the low‐to‐medium range of vapor loading
Heats of mixing for homologous series of ketones and their prediction from group interaction theory and the congruence principle
Authors: Ramalho R. S. , Tillie J. L. , Kaliaguine S.
Published: March 2009

Heats of mixing for 12 binary systems of ketones at several temperatures are reported. Application of an extension of the congruence principle and the group interaction theory is studied, for these data. A graphical procedure for prediction of heats of mixing data is proposed
Mathematical modeling of a modified scheibel liquid‐liquid extraction column in the frequency domain
Authors: Pang K. H. , Johnson A. I.
Published: March 2009

The frequency response of a modified Scheibel liquid‐liquid extraction column was experimentally determined from pulse testing data obtained by Pollock. Mathematical modeling was carried out in the frequency domain. Several non‐identical, non equilibrium, perfect mixing stage models were used to describe the dynamic behavior of the column. A signal flowgraph technique was found to be suitable for determining the theoretical frequency response of the non‐identical stage models. All models proposed in this study appeared to simulate satisfactorily the behavior of both the extract and raffinate phases. The theoretical frequency and transient responses agreed very well with experimental data
Heat and mass transfer during air drying of solids
Authors: Bimbenet J. J. , Loncin M. , Brusset H.
Published: March 2009

Heat and mass transfer are studied for drying of a semi‐infinite solid in warm air. The mathematical model, a system of partial differential equations, gives an exact analytical solution if transfer coefficients are constant and free water present at the surface. An analogy has been found for heat transfer with and without drying. A finite‐difference solution of broader application than the analytical method has been developed, and the two methods agree closely. Experiments are described which show fair agreement with calculations of heat transfer during the first step of drying. Water content profiles remain flat during that period and no precise comparison can be made
Prediction of heats of mixing of liquid mixtures containing aliphatic hydrocarbons and ketones by a group solution model
Authors: Nguyen T. H. , Ratcliff G. A.
Published: March 2009

A group solution model for heats of mixing of liquid mixtures has been tested and found satisfactory for mixtures containing ketones and alkanes. No provision was made for a skeletal contribution

Group contribution functions were generated from experimental data on acetone/n‐hexane mixtures at 25°C and are presented. These functions allow the prediction of heats of mixing of binary or multicomponent mixtures containing alkanes and/or ketones at 25°C. No experimental data are required
The dispersion of material in slowly moving fluids
Authors: King R. P. , Woodburn E. T. , Riele W. A. M. Te
Published: March 2009

The dispersing action of a mass of slowly moving fluid is modelled by a stochastic partial differential equation. The separate components of the fluid velocity are represented as stochastic processes and appear as coefficients in that equation. These processes can take one of two forms: Markov processes with finite state‐space, or independent Ornstein‐Uhlenbeck processes.

To confirm the predictions of the model they were compared with the mean response to a pulse‐like injection of tracer and with the observed cross‐correlation between tracer concentration at two points in the fluid. The statistical properties of the velocity processes, as estimated from these tracer studies, were confirmed by direct measurement with a hot‐film anemometer probe.
The effect of non‐uniform porosity in causing flow maldistributions in isothermal packed beds
Authors: Stanek V. , Szekely J.
Published: March 2009

A formulation is developed for the flow of an incompressible fluid through a two dimensional packed bed having a spatially variable void fraction, through the statement of the Ergun Equation in a two dimensional system.

Computed results are presented for particular spatially distributed void fractions in the bed, which indicate that a lateral variation in the resistance to flow may cause appreciable flow maldistribution and “cross flow” effects.

This work is thought to be a first, necessary step in the quantitative understanding of channeling and by‐pass phenomena in packed bed reactors.
The grinding of organic dyestuffs
Authors: Jenczewski Theodore J.
Published: March 2009

A mechanism for grinding disperse dyes in a sand mill is discussed which is supported by experimental data. Experimental data with disk, cylinder and vibrator agitators are examined from the point of view of dimensional analysis. All rotors exhibited fluid slip and decreased efficiencies at high rotor speeds. Cylinder rotors provided higher rates of energy input to the milling paste, and shorter grinding times, relative to disk and vibrator agitators.
Prediction of enthalpy of saturated paraffin binary hydrocarbon mixtures
Authors: Ghormley E. L. , Lenoir J. M.
Published: March 2009

A method of predicting the thermal phase boundary of aliphatic hydrocarbons is presented. Equations describe the saturated enthalpy boundary of pure substances and binary mixtures of hydrocarbons up to the critical temperature. A method of predicting the cricondentherm has been developed to establish the upper limit of the enthalpy envelope for binary mixed aliphatic hydrocarbons. Calculated enthalpies have an average deviation of 0.5% for pure hydrocarbons and 0.8% for mixed hydrocarbons.
The excess enthalpy of gaseous mixtures of carbon dioxide with methane
Authors: Lee J. I. , Mather A. E.
Published: March 2009

Excess enthalpies (heats of mixing) of mixtures of methane and carbon dioxide have been measured in a flow calorimeter at temperatures between 10°C and 80°C and pressures up to 100 atmospheres. All measurements were for the mixing of two gas phases. The results were compared with various predictions based on equations of state and the principle of corresponding states.
On the merits of partial fluid mixing in the biochemical reactor system
Authors: Chen Gilbert K. C. , Fan L. T. , Erickson L. E.
Published: March 2009

For autocatalytic reactions such as those associated with many biochemical processes, the rate of a reaction is influenced by the concentrations of some of the products as well as those of the reactants. By use of the so‐called diffusion (axial dispersion) model in conjunction with the Monod growth kinetics, it is shown that partial (incomplete) fluid mixing is often desirable for this class of reactions. Under sterile feed conditions, the optimal Peclet number appears to range between 0 and 2 with the exact value depending on the values of the kinetic constants and initial substrate concentration. By varying this single parameter, the performances of such reactors under various degrees of fluid mixing can be readily investigated using the axial dispersion model. The optimal design may be physically realized by the use of a tower fermentor with controlled axial dispersion.
Activation analysis of environmental pollutants
Authors: Chattopadhyay A. , Bennett L. G. I. , Jervis R. E.
Published: March 2009

Activation analysis is a highly sensitive and specific technique for the detection of trace heavy metal pollutants in environmental materials. Comparison of natural “baseline” levels with elevated levels provides direct evidence of contamination. Neutron activation analysis (NAA) is used in this study to determine arsenic, zinc, cadmium, and mercury. Photo‐nuclear activation analysis (PNAA) is used to determine lead in soils. Holland Marsh, a market‐gardening area north of Toronto, has been studied as various herbicides and fungicides have been used there. The analyses of soil and vegetation samples, and of human head hair collected from residents are reported.
Radial mixing and residence times in the liquid phase in gas‐liquid annular flow in vertical tubes
Authors: Jagota A. K. , Scott D. S. , Rhodes E.
Published: March 2009

Theory for calculating the mean velocities of the drops and of the film in gas‐liquid cocurrent annular flow by use of tracer pulse techniques has been developed. It is shown that the interaction between the film and the drops affects the mean residence times in each, and is much greater in its effect than is axial dispersion in the film or in the core.

The theory also describes a relatively simple means of determining the mean amounts of droplet entrainment and liquid interchange between droplets and film from measurements made with continuous tracer injection. Knowledge of the entrainment and the mean velocities of film and drops is essential in determining the extent of interaction between the liquid film and the entrained liquid flow.
Flow visualization studies of a turbulent drag reducing solution
Authors: Arunachalam V.R. , Hummel R. L. , Smith J. W.
Published: March 2009

A nondisturbing photochromic dye trace technique has been employed to study the flow profiles of water‐alcohol solutions containing the drag reducing polymer Polyox at concentrations of 0.55 to 5.5 ppm. Drag reductions of from 33 to 75% were observed in a smooth glass pipe. The dye traces show a thicker wall layer for the drag reducing solutions than that for the solvent alone. The core region is relatively unaffected by the polymer at 0.55 ppm and at 5.5 ppm the relative thickness of the turbulent core region has been greatly reduced. Earlier, unpublished work of Corinthios shows effectively no core at 33 ppm. Mean velocity and apparent axial turbulence intensity profiles obtained are in general agreement with previous data in the literature obtained with other methods and in the wall region the low frequency intensity is greater than that of the pure solvent. This is consistent with the results of Spangler but not those of Seyer. Higher low frequency intensities measured in the wall region suggest that higher frequency fluctuations are suppressed and/or that the time stability of eddies is increased as indicated by the reduced frequency of wall ejections in drag reducing solutions.
The solubility of hydrogen in aliphatic amines
Authors: Moore R. G. , Otto F. D.
Published: March 2009

The solubility of hydrogen in ammonia, monomethylamine, monoethylamine and n‐propylamine was determined at temperatures from −70°C to 25°C and in 1,2‐propanediamine and 1,2‐ethanediamine over the temperature ranges −25°C to 11°C and 25°C to 34°C respectively. Measurements were made at total pressures up to 300 psig. The solubility data were correlated in terms of Henry's law and the solubilities are in the range 1 × 10−5 to 3 × 10−4 mole fraction at a hydrogen partial pressure of 1 atmosphere. The measured solubility data were used to extend a correlation proposed by Yen and McKetta. This revised correlation may be used to estimate the solubility of hydrogen in polar, associated amines.
Experimental evaluation of feedback, feedforward and combined feedforward‐feedback binary distillation column control
Authors: Wood R. K. , Pacey W. C.
Published: March 2009

The control behavior of a nine inch diameter eight tray bubble cap column separating a methanol‐water mixture has been studied using feedback, feedforward and combined feedforward‐feedback control. Top product composition was controlled by manipulation of the reflux rate to compensate for feed flow disturbances. Pulse testing was used to determine the process transfer functions. Gain, gain plus time delay and gain plus time lag feedforward control were implemented by means of an IBM 1800 digital computer. Combined feedforward‐feedback control, using gain and gain plus time lag feedforward control action, was also studied. The improved column control behavior is compared with results obtained using only feedback control.
Some problems concerning the non‐adiabatic tubular reactor a‐priori bounds, qualitative behavior, preliminary uniqueness and stability considerations
Authors: Varma Arvind , Amundson Neal R.
Published: March 2009

An investigation of the non‐adiabatic tubular reactor, in which a single chemical reaction occurs, is presented. The steady state mass and heat balance equations are shown to be a pair of coupled, nonlinear differential equations, and are shown to uncouple into a single functional‐differential equation for the case Le = 1. A‐priori bounds on the steady state concentration and temperature are developed, and some remarks about the shape of the steady state profiles made. Sufficient conditions ensuring uniqueness of steady states and their asymptotic stability are derived.
Some statistical properties of turbulent momentum transfer in rough pipes
Authors: Dunn S. G. , Smith J. W.
Published: March 2009

A non‐disturbing technique has been used to measure turbulence parameters in a smooth pipe and in two randomly roughened pipes at the same apparent wall shear.

Near the wall, large eddies are significantly more intense in smooth than in rough pipes while the small eddies are more intense in rough than in smooth pipes. No viscous sublayer was visible in the rough pipes. In the core, large apparent differences in large scale eddy structure were found between rough and smooth tubes, but the differences probably result from the inappropiate inclusion of dissipation due to form drag in u*.
The hydrogenolysis of n‐Butane on a nickel on silica catalyst: II Fluidized bed studies
Authors: Orlickas A. , Hoffman T. W. , Shaw I. D. , Reilly P. M.
Published: March 2009

This study was undertaken to obtain experience in developing steady‐state mathematical models of full‐scale chemical reactors through the use of a combination of bench‐scale experiments and actual plant operating data. In this case, the hydrogenolysis of n‐butane on a nickel on silica gel catalyst was studied in a %inch diameter pilot plant fluidized bed reactor. The kinetic parameters in a mechanistic reaction model were obtained in a bench‐scale integral reactor and these rate equations were included in a simple two‐phase fluidized bed model. The parameter relating to interchange of gas between bubbles and emulsion was determined from the fluidized bed data. A comparison of the predicted and observed selectivities suggested a weakness in the kinetic model. This shortcoming was then partially corrected by using the fluidized bed data. In this way, a reactor model was achieved which was satisfactory for overall plant simulations.
Mathematical model and optimization of drying process for a through‐circulation dryer
Authors: Chung Seng F.
Published: March 2009

A mathematical model of a through‐circulation dryer is proposed. This model approximates the drying time of constantrate drying and fallingrate drying processes. Based on the proposed model, the optimal drying conditions of maximizing the drying production rate in a continuous through‐circulation dryer are obtained. The drying production rate, in terms of the independent operating variables, is a nonlinear objective function, and is optimized under the nonlinear inequality constraint functions by a differential algorithm.
An improved algorithm for solving the mass balance equations in multistage separation processes
Authors: Boston J. F. , Sullivan S. L.
Published: March 2009

The reliability and efficiency of any method of solving the equations that describe multicomponent, multistage, counter‐current separation processes depend on the accuracy and efficiency of the algorithm that is employed to solve the component mass conservation (CMC) equations. Previous investigators have shown that ordinary Gaussian elimination is very efficient for solving the CMC equations when they are expressed in tridiagonal form. The present work, however, demonstrates that this procedure is subject to excessive round‐off error under certain conditions. In such cases, the error can be reduced to insignificant levels by using a newly developed algorithm based on recursion formulas derived specifically to treat the tridiagonal system of CMC equations.
Experimental heat capacities of nitrogen‐carbon dioxide mixtures at elevated pressures
Authors: Bishnoi P. R. , Hamaliuk G. P. , Robinson D. B.
Published: March 2009

The heat exchanger method of determining the ratio of heat capacity at a pressure to the heat capacity at a low pressure was used to obtain data on two binary mixtures of nitrogen and carbon dioxide containing 6.77 and 31.70 mole percent nitrogen. The data were obtained at pressures up to 2150 psia in the temperature range from ambient to 90°C. The results are believed to be accurate within ± 0.5% in the regions removed from the pressure maxima and within ± 1% in regions close to the maxima. Heat capacities of the two binary mixtures calculated using the BWR equation of state and new mixing rules compared favourably with the experimental data.
Testing consistency of vapor‐liquid equilibrium data in P‐T‐X space
Authors: Brinkman Norman D. , Weber James H. , Tao Luh C.
Published: March 2009

A systematic method of calculating and presenting the results of consistency tests is given and illustrated on the methane‐ethane system in the space of −140 to 60°F and 100 to 700 psia. The results indicate incompatibility of error levels between isobars and isotherms. Also, different arrangements of terms in the thermodynamic differential equations were sometimes found to produce different levels of inconsistency for the same space. Results are analyzed and discussed.
Velocity measurements in turbulent flow of viscoelastic solutions
Authors: Rollin A. , Seyer F. A.
Published: March 2009

An experimental study, based on streak photograph determination of instantaneous velocities, was directed at determining the turbulent flow velocity profiles of polymer solutions in circular pipes. The measurements resolve several discrepancies in interpretation of earlier velocity profile measurements in drag reducing systems. In particular, it is shown for dilute drag reducers that the semilogarithmic profile due to Prandtl with the same slope as for Newtonian fluids is quantitatively correct provided Bogueés empirical correction function is applied to the data. For a relatively concentrated solution, data serve to extent on earlier study which has shown the flow to be transitional at surprisingly high values of Reynolds number.
Studies of ethylene chlorohydrin formation in a bubble column reactor
Authors: Saeki G. , Weng P. K. J. , Johnson A. I.
Published: March 2009

An experimental study of the reactions of ethylene, chlorine, and water in a bubble column reactor, on a laboratory scale, has been carried out. The effect of gas flow rates on the yield of the products in an unbaffled reactor is reported. Baffles were introduced into the column to reduce axial mixing. A significant improvement in the conversion and yield of ethylene to ethylene chlorohydrin was observed.
Fonction de transfert déun réservoir agité en système continu: I. Détermination à léaide déun traceur fluorescent
Authors: Pineault Gilles , Cloutier Leonce
Published: March 2009

A fluorescent material which does not disturb the physical properties of the contacting fluids while allowing a continuous analysis of the concentration, has been used to study the mixing of two miscible liquids in a continuous stirred tank reactor (CSTR). The experimental results for three types of forcing functions, analysed by the frequency response method and Bode diagrams, show that a general first order transfer function describes the behavior of a CSTR when there is no density difference between fluids.
Sorption in davison 5 a molecular sieves
Authors: Ruthven D. M. , Derrah R. I.
Published: March 2009

Kinetic and equilibrium data are reported for the sorption of propane, propylene and 1‐butene in two commercial 5A molecular sieves (Davison C‐521 and C‐626). It is shown the kinetics of sorption are controlled by the diffusional resistance of the macropores and tortuosity factors are calculated from the experimental data. Rates of sorption are compared with previous data for the Linde 5A sieve. For measurements over large step changes in concentration, adsorption is much faster than desorption but these differences can be quantitatively accounted for by considering the non‐linearity of the equilibrium isotherms.
Foam fractionation of solutions containing two surfactants in stripping and reflux columns
Authors: Rubin Eliezer , Melech Doron
Published: March 2009

An experimental and theoretical investigation was undertaken in order to examine the effect of concentration, foam flow rate and feed flow rate on the separation of sodium dodecylbenzene sulfonate and sodium lauryl sulphate from solutions containing the two surfactants, in stripping and reflux columns. The experimental results indicated the conditions under which a stripping foam fractionation column behaves according to the model of an infinite column. Within the present experimental range reflux columns behaved always according to the model of an infinite column. Using this model it is possible to predict relative separation of surfactants in stripping and reflux columns from experimental data obtained in simple columns. Experiments with modified total reflux columns indicate great potential for batch foam fractionation.
The effect of concentration on the rates of dissolution of gibbsite and boehmite
Authors: Scotford R. F. , Glastonbury J. R.
Published: March 2009

The effect of caustic soda concentration on the rate of dissolution of gibbsite and boehmite was studied. The activity of sodium hydroxide rather than cencentration was found to be the best parameter for kinetically describing the effect of concentration on dissolution rate.

For the gibbsite reaction, a first order dependence on sodium hydroxide activity was observed whilst the boehmite dissolution exhibited a dependence on the term (aNaOH. aH2O) which was first order above 210 g/1 Na2O and half order below that concentration.
Evaluation and improvement of control vector iteration procedures for optimal control
Authors: Rao S. Nagaraja , Luus Rein
Published: March 2009

To improve the convergence rate to the optimal policy, a simple but effective way of determining the stepping parameter for the control policy adjustment is developed. The application of the proposed approach to four systems described by ordinary differential equations shows that the existing methods are improved considerably when the proposed method is incorporated.
Vortex nozzles for limitation of discharge rates
Authors: Boadway J. D.
Published: March 2009

The vortex nozzle, employing the radial pressure differential across a vortex can be effective in limiting the discharge of fluid or slurries from pressurized systems without using small throttling orifices which could plug readily.

This paper deals with an investigation of vortex discharge devices which use this principle: It features measurements of velocities using a photographic trace technique. The measured radial distribution of mean tangential velocity departed from a free vortex pattern due to friction losses at the walls of the equipment. Empirical equations were developed for the tangential velocity and the flow, the coefficients being related to parameters of the design.
Migration of dispersed phases in a pulsed liquid in a pipe with asymmetric baffles
Authors: Chan K. W. , Baird M. H. I.
Published: March 2009

Dispersed particles tend to migrate in a preferred direction in a pulsed liquid flow in the presence of fixed baffles of asymmetric design. Conical and inclined disc baffles were found to promote migration of dense materials (sand, hematite) up an inclined length of 5.08 cm. diameter pipe. Conical baffles were effective in increasing the gas holdup in a vertically pulsed bubble column, provided the thick end of the cone was uppermost. These effects are thought to be due to the entrainment of the dispersed phase into separation vortices. Energy dissipation measurements with conical baffles are consistent with this model.
Prediction of vapor‐liquid equilibria by means of a modified clausius equation of state
Authors: Elshayal I. M. , Lu B. C.‐Y.
Published: March 2009

The Clausius equation was modified for the calculation of vapor‐liquid equilibria in binary and multicomponent systems. In the modification, the three parameters of the equation were considered temperature dependent. Molal volumes of saturated liquid and vapor together with the condition that the fugacities of the vapor and the liquid phase are equal at the condition of equilibrium were used for evaluating the parameters of pure components. Applications were made successfully to systems nitrogen‐methane, nitrogen‐oxygen, argon‐oxygen, nitrogen‐argon, argon‐methane, carbon dioxide‐hydrogen sulfide, carbon‐dioxide‐propane, hydrogen sulfide‐n‐butane and nitrogen‐argon‐oxygen.
Comparaison du modèle des réservoirs imparfaitement agités en série avec le modèle de dispersion axiale
Authors: Bang Vo Van , Cholette A.
Published: March 2009

On présent la fonction de transfert du modèle des réservoirs imparfaitement agités en série, comportant les trois paramètres p, m et n. Elle permet d'évaluer facilement la courbe de distribution du temps de séjour E(θ) et la réponse à une demande à l'entrée.

Ce modèle est comparé au modèle de dispersion en se basant sur la variance de la courbe E(θ) et sur l'erreur moyeune absolue entre les valeurs théoriques et les données expérimentales. Un graphique permet de relier le nombre de Péclet du modèle de dispersion axiale aux paramètres du modèle p, m, n et aussi à la variance de la courbe E(θ).

Le modèle p, m, n donne une bonne approximation des données expérimentales et s'avère plus souple que le modèle de dispersion axiale.
A cationic surfactant as a soluble ion exchanger in the continuous foam fractionation of nitrate; iodide, and bromide
Authors: Grieves R. B. , Bhattacharyya D. , The P. J. W.
Published: March 2009

An experimental investigation is presented of the continuous foam fractionation of NO3− versus Br− and of T− versus Br− with a quaternary ammonium surfactant at concentrations of the order 1.8 × 10−4M. An equation is derived to enable the computation of anion selectivity coefficients from foam fractionation data. The key assumptions of the derivation are verified experimentally. The selectivity coefficient for NO3 versus Br− is 1.56 ± 0.28 and for I− versus Br− is 5.85 ± 1.81, established from 40 continuous‐flow experiments. Precipitation of EHDA‐I is indicated at the highest ratios of the bulk solution concentrations of I− and Br−. significantly, both selectivity coefficients are independent of the fraction of the exchanger occupied by the preferred ion, indicating an exchanger activity coefficient ratio of unity, and are independent of ionic strength. The counterion present markedly influences the surfactant distribution coefficient.
Removal of fine particles from water by dispersed air flotation: Effects of bubble size and particle size on collection efficiency
Authors: Reay David , Ratcliff G. A.
Published: March 2009

A theoretical treatment is presented which attempts to quantify the benefits obtained by using smaller bubbles or larger particles in dispersed air flotation. The limited experimental data obtained so far suggest that the theory is sound, particularly in its prediction of the effect of bubble size.
Submerged culture growth of edible mushrooms on waste sulphite liquors
Authors: Kosaric N. , Leduy Anh , Zajic J. E.
Published: March 2009

Various waste sulphite liquors (WSL) i.e. NH3−, Mg‐, Ca‐, and mixed‐base, were used as substrates for submerged cultivation of four species of edible mushrooms (morel mushroom): Morchella spp., Morchella crassipes, Morchella deliciosa, Morchella esculenta. Growth was found to be completely inhibited by calcium found in both Ca‐WSL and mixed‐WSL. (In NH3− WSL and Mg‐WSL growth generally occurs in large pellet form.

The optimal initial pH for the different morel species on various WSL was found to be between 5.0 and 7.0. The highest yield (approximately 83.4% based on utilized carbohydrate) and dry weight (approximately 4.86 g/l) were obtained when the NH3− WSL was diluted (1:5 v/v) and used for growth of Morchella crassipes. Freeze‐dried morel mushroom mycelium (MMM) on WSL contains on a dry basis, 25.7‐48.0% crude protein, 2.45‐4.38% fat, 13.7‐39.2% carbohydrate and 5.9‐18.0% ash. The spectrum of essential amino acids is comparable to the FAO standard, except for the levels of methionine and isoleucine. A strong mushroom flavor (aroma and taste) is also conserved in freeze‐dried powdered samples.
Equilibre entre vapeur et liquide pour le système azote‐argon‐methane
Authors: Gravelle Denis , Lu Benjamin C.‐Y.
Published: March 2009

On a mesuré au moyen d'un apparcil à re‐circulation forcée les compositions d'equilibre entre la vapeur et le liquide pour le système azote‐argon‐méthane à 123.4°K.

Les résultats obtenus de cet appareil ont été représentés avec succès par l'équation d'état de Redlich‐Kwong. On a modifié celle‐ci en y incurporant unc constante d'action réciproque binaire kij et en considérant les constantes caractéristiques de l'équation Ωa et Ωb comme étant fonction de la température, pour chaque composant. On a aussi évalué les constantes d'équilibre à partir de l'équation d'état pour ensuite les comparer avec les valeurs experinientales. Les moyennes absolues des déviations sont 1.62%, 1.67% et 7.57% pour les composants azote, argon et méthane respectivement.
Transition to unsteady flow and intensity of velocity fluctuations in a porous medium
Authors: Kingston George , Nunge Richard J.
Published: March 2009

Direct measurements of local velocity and the intensity of velocity fluctuations in a pore of a number three rhombohedral array of spheres indicate a region of increasing intensity beginning at Reynolds number of about 80 and reaching a maximum intensity of approximately 0.6 at a Reynolds number of about 200. At higher Reynolds numbers the intensity falls to a constant value between 0.4 and 0.5.
An empirical equation of state for gases
Authors: Sandri R.
Published: March 2009

A simple pressure‐explicit empirical equation of state for gases is presented which contains five constants in addition to the gas constant. It has been applied to carbon dioxide, hydrogen and nitrogen. The equation gives good accuracy (with maximum errors slightly higher than 1%) for densities up to critical and for temperatures from slightly above critical up to very high values. Below critical temperature it can still be applied with reasonable accuracy to the vapor. Thermodynamic functions (internal energy, enthalpy and entropy) derived from this equation show simple form and satisfactory accuracy over a wide range of temperature and density.