bluuebunny/crossref_metadata_2025 huggingface dataset:
An analysis of horizontal stratified two phase flow in pipes
Authors: Agrawal S. S. , Gregory G. A. , Govier G. W.
Published: March 2009

Using a mechanistic approach, equations are developed to describe the stratified cocurrent flow of gas‐liquid mixtures in horizontal pipes. An iterative method is suggested for their solution.

Experimental data were collected using air‐oil mixtures in a one inch 1. D. by 101 ft. long acrylic pipe. Pressure drop and average in situ liquid volume fraction are presented as a function of the superficial gas velocity and are compared with predicted results from this study and other models reported in the literature.

Visual observation of flow patterns and their transitions are indicated on the tentative flow pattern map of Govier and Aziz(1).
Solubilities of the highly soluble gases, propane and butane, in normal paraffin and polar solvents
Authors: Hayduk W. , Castaneda R.
Published: March 2009

The solubility of highly soluble gases in both polar and non‐polar solvents has been found to approach a mole fraction of unity as the solution temperature is reduced toward the normal boiling point of the dissolved gas. Solubilities of all gases in the polar solvents chlorobenzene, normal butanol and acetone, tend toward a common reference solubility for each solvent as the temperature is increased toward the solvent critical temperature. Solubilities of propane as measured in this work are reported at 0°C, 25°C and 50°C in chlorobenzene, butanol and acetone and at 25°C in hexane and hexadecane, along with solubilities of butane at 5°C, 25°C and 50°C in hexane, heptane, octane, dodecane, hexadecane and butanol. These data, along with those from literature sources, have been utilized in formulating the above generalizations.
Quantitative analogies between the linear and non‐linear viscoelastic functions
Authors: Hlavacek B. , Seyer F. A. , Stanislav I.
Published: March 2009

A method of determination of linear and non‐linear viscoelastic functions is proposed. Through this method it is possible to calculate the non‐linear functions P11 ‐ P22 and η(γ) assuming that linear viscoelastic function (ω) is known. Alternatively from the function P11 ‐ P22 we are able to calculate η(γ) and y'(ω) etc.

The method is based on the assumption that the change from linear to non‐linear functions is proportional to a molecular deformation for shear stress components P12, and is dependent on the square of the deformation for the first normal stress difference, P11 ‐ P22. The obtained results suggest straightforward modification of equations of state, this being demonstrated with the White‐Metzner model of the convected Maxwell element.

Consideration of available experimental data shows that this theory is capable of predicting the various functions, at least as well as currently available constitutive equations, while requiring less experimental information.
The non‐adiabatic tubular reactor: Stability considerations
Authors: Varma Arvind , Amundson Neal R.
Published: March 2009

This paper is a continuation of four previous ones in this journal (1, 2, 3, 4) and is involved with the transient and stability behavior of a non‐adiabatic unpacked tubular reactor. The steady states found earlier are tested for stability both by computing transient profiles and by computing the eigenvalues of the appropriate linearized problem. It is found in all cases that the two computations predict the proper stability behavior. It is shown that in some cases all steady states for a given set of parameters may be unstable and that a unique steady state may give rise to an oscillatory system.
The chemical engineering approach to some electrochemical processes
Authors: Fahidy T. Z.
Published: March 2009

In recent years much research has been carried out in combining electrochemical processes with chemical engineering techniques, and in general, to apply principles of analysis and design of this discipline in search for new electrochemical technologies. This paper reviews seven major areas of activity in modern applied electrochemistry where the chemical engineering approach has been successful: Fluidized bed electrochemical reactors; Bipolar particulate reactors; Pulsed electrochemical reactors; Gas phase electrochemical reactors; Electrocrystallization and electrodissolution; Enhancement of heat and mass transfer in electric fields; dynamics, modelling and optimization of electrochemical reactors.
Amino sulphonic resins for chlorine exchange
Authors: Wayman Morris , Cheung Leon K. L.
Published: March 2009

The introduction of sulphonic groups to urea melamineformaldehyde resins has been shown to improve their performance as chlorine exchange resins for treatment of drinking and swimming pool waters. The preparation of resins containing a range of sulphonic content (UMFS resins) is described. Suspension polymerization produced resin beads suitable for use in fluidized beds. Scanning electron microscopy showed the resin structure to be macroreticular, porosity increasing with the sulphonic content in the formulation. Chlorination of water by fluidized beds of such resins showed that the activity increased with sulphonic content, steady state residual chlorine levels of 2 to 4 ppm being obtained with 0.5 or 1 mole sulphonic group per mole urea in the formulation.
Growth of a sulphuric acid droplet exposed to water vapor
Authors: Azarniouch M. K. , Bobkowicz A. J. , Cooke N. E. , Farkas E. J.
Published: March 2009

The growth of a droplet of concentrated sulphuric acid suddenly exposed to water vapor was investigated. Droplet size and temperature as functions of time were obtained by numerical solution of droplet mass and energy balances. Inclusion of heat effects is thought to be an advance over previous studies of droplets of dilute acid which could be assumed to remain isothermal during the growth process. The results indicate that the growth process is completed in a few milliseconds for micron‐size droplets. The solutions presented are applicable to the continuum regime and the results are compared with experimental and calculated results of previous workers.
A general algorithm for multistage multicomponent separation calculations
Authors: Ishii Yoshikazu , Otto Fred D.
Published: March 2009

This paper presents a new general calculational method for equilibrium stage processes. The method employs a multivariate Newton procedure to solve all equations simultaneously for corrections to temperatures, flow rates and compositions. The linearized model equations are selected so that only 2N (1 + NCP) partial derivatives need to be evaluated per iteration. Experience to date indicates that the method is reliable for both distillation and absorption problems and requires less computing time than current procedures. The rigorous solution of a reboiled absorber problem for 16 stages and 15 components required 5 iterations and 14.4 seconds on an IBM 360/67 computer even when the Chao‐Seader correlation was employed for the direct calculation of composition dependent equilibrium and enthalpy data.
Geometry of bluff body wakes
Authors: Kalra T. R. , Uhlherr P. H. T.
Published: March 2009

The attached recirculating wake zone has been experimentally investigated for spheres, spherical caps and circular discs normal to the flow. Tracer photography in a water tunnel was employed for the measurements. Results are presented over the range of Reynolds number from 20 to 400. The following wake properties are presented as a function of Reynolds number: angle of separation for spheres; wake length for spheres and discs, wake volume for all three types of body.

The results for separation angle are in good agreement with the data available from the literature, both experimental and theoretical. Wake length results for spheres are also in agreement with published values and with values obtained from published numerical solutions of the equations of motion. Wake volume results for spheres are similarly in agreement with values calculated from published wake dimensions obtained both experimentally and theoretically.

Spherical caps are found to have the wake volume either of discs if they are thin (h/D <0.3) or of spheres if they are thick (h/D > 0.6). Caps of intermediate thickness to diameter ratio show a transition between sphere‐like and disc‐like behavior. This behavior is explained in terms of the separation angle on spheres.
Frequency response in liquid fluidized systems Part I. Effect of particle density and size
Authors: Krishnaswamy P. R. , Shemilt L. W.
Published: March 2009

Fluid mixing in liquid fluidized beds has been characterized by a dynamic response technique using pulse inputs. Solid particles with a size range of 0.5 to 3.0 mm diameter and a density range from 1.28 to 7.02 gms/cc were fluidized with water at void fractions of 0.4 to 0.85 in a 2‐inch column. A dispersed plug flow model has been applied successfully, including a frequency response comparison, and dispersion coefficients have been calculated by the moments method. The results are related to correlations previously advanced, including the use of an eddy diffusivity and of the Bodenstein number, and a more recent refined correlation allowing for density differences.
Lattice theory correlation for binary gas adsorption equilibria on molecular sieves
Authors: Lee A. K. K.
Published: March 2009

A correlation method is presented for calculating the adsorption equilibria of a binary gaseous mixture and the total amount adsorbed, using pure‐component adsorption isotherms and a mixture parameter. The proposed method is based on the lattice theory of solutions and the concept of volume filling of microporous adsorbents. The method has been successfully applied to literature data for the adsorption of binary gas mixtures in molecular sieves type 5A, type 10X and H‐mordenite.
Biological wastewater treatment system design Part I. Optimal synthesis
Authors: Mishra Prakash N. , Fan Liang‐Tseng , Erickson Larry E.
Published: March 2009

Common practice for design of biological wastewater treatment systems involves evaluation of certain fixed structure systems at several alternative conditions. This study considered optimization of both the structure and the design of the system using the structural parameter system synthesis technique. The system was composed of a trickling filter, an activated sludge aeration vessel, and a secondary clarifier. Results of optimal synthesis indicated that the activated sludge system was the most cost effective system for the specific set of process parameters employed. The same conclusion was reached by optimizing several systems with different structures.
Biological Wastewater Treatment System Design Part II. Effect of Parameter Variations on Optimal Process System Structure and Design
Authors: Mishra Prakash N. , Fan Liang‐Tseng , Erickson Larry E.
Published: March 2009

This paper presents a study of the effects of parameter variations on optimal process system structures and designs for biological wastewater treatment systems. Results indicate that optimal system structure and design are sensitive to variations in the rate constants and feed concentration. Some of the process flowsheets deduced are innovative and have surprisingly low total costs. The process system structures and designs developed in this study merit consideration in future planning and design of wastewater treatment systems.
Kinetics and thermodynamics of oxygen chemisorption on an industrial vanadium oxide catalyst
Authors: Stanislaus A. , Evans M. J. B. , Mann R. F.
Published: March 2009

The chemisorption of oxygen on an industrial vanadium pentoxide/potassium sulphate catalyst has been studied in the temperature range 300‐353°C by a gravimetric technique. Agreement of equilibrium data with the Langmuir and Freudlich equations is not entirely satisfactory. The kinetic measurements suggest that at least two mechanisms are involved in oxygen chemisorption under certain conditions. At low coverage Langmuir or Elovich kinetics are followed reasonably closely although a pressure dependence is apparent suggesting dissociation into oxygen atoms before a final chemisorbed state is reached. Diffusion is suggested as the possible ratedetermining process at higher coverage. Langmuir analysis of the kinetics as equilibrium is approached shows that an unexpected pressure dependence also exists in this region.
A Generalized Correlation for Predicting Saturated Liquid Densities of Mixtures
Authors: Chiu C. ‐H. , Hsi C. , Ruether J. A. , Lu B. C. ‐Y.
Published: March 2009

A generalized correlation for saturated liquid densities of pure compounds, based on the Guggenheim equation, has been extended for applications to mixtures. The method employs a mole‐average acentric factor and scaling volume, and a weighted average critical temperature for the mixture. The method was tested on twenty‐four binary and two ternary systems comprising hydrocarbons and non‐hydrocarbons. Overall average absolute deviation in predicted densities is less than two percent for a total of 1,096 data points.
Transient turbulent transport processes accompanied by first order chemical reactions or heat generations
Authors: Chung Benjamin T. F. , Wang Roger C. C. , Thomas Lindon C.
Published: March 2009

A mathematical model of transient transport processes with homogeneous first‐order chemical reactions or heat generations is developed. The analytical expressions for the local transport coefficient and the mean potential profile are derived based on the film renewal and penetration concept. Solutions are presented graphically in terms of various dimensionless parameters. From the proposed formulations, the transient, reaction and surface resistance effects to the turbulent interphase heat or mass transfer can be analyzed.
A vortex model to relate eulerian and lagrangian “ turbulent” velocity fields
Authors: Base T. E. , Davies P. O. A. L.
Published: March 2009

The phenomenon of turbulent diffusion was studied by using computed models. Free pseudo‐turbulent fluid flow was simulated on a digital computer by ensembles of randomly positioned moving and interacting vortices to represent the eddy structure of the turbulence. A vortex model, which had statistical values corresponding to a measured real flow in an Eulerian frame of reference, was then obtained. By considering the motion of a particular vortex or a fluid particle in the computed pseudo‐turbulent flow it was possible to determine measurements in a Lagrangian frame of reference. Estimates of the mean square lateral excursions of a marked particle were obtained and finally the Lagrangian auto correlation was compared with the auto correlation in a moving frame of reference.
Effect of a variation in perforation size on performance of sieve tray absorbers
Authors: Pruden B. B. , Hayduk W. , Laudie H.
Published: March 2009

A six inch diameter sieve plate absorption column was used to assess the effect of perforation size on the performance of sieve trays under otherwise identical conditions. Four separate test trays with equal gas flow areas but perforations of 1/8‐inch, 1/4‐inch, 1/2‐inch and 1‐inch respectively, were used with the liquid phase absorption‐controlled system of carbon dioxide — water at 77°F and approximately 830 mm. mercury.

Comparisons of overall efficiencies indicated that the trays with 1‐inch diameter perforations had efficiencies similar to, or slightly lower than those of 1/8‐inch diameter. Concentration profiles within the froth were measured, with distinct profiles being observable in both the horizontal and vertical directions.

This indicated that neither the plug flow nor the completely mixed models accurately described the actual transfer process. Accordingly, comparisons of volumetric mass transfer coefficients computed from both models were made. Comparison of volumetric mass transfer coefficients showed that for most gas and liquid flowrates the plates with 1‐inch perforations performed as well as plates with smaller holes. For this system it was concluded that trays with large holes would be much better suited to fouling services and, indeed, they would be only marginally less attractive than trays with smaller holes for all services.
A coupling model for the effect of ultrasonics on chemical reactions
Authors: Couppis Evis C. , Klinzing George E.
Published: March 2009

In an effort to obtain a macroscopic model predicting the effect of ultrasonics on chemical reactions, irreversible thermodynamic coupling between the chemical reaction rate and the trace of the viscous pressure tensor is investigated. The analytical predictions of the proposed model will be verified by the presentation of experimental data showing the effect of ultrasonics on the reaction rates near equilibrium conditions for the hydrolysis of methyl acetate.
Irradiation of butadiene‐styrene copolymers
Authors: Chau T. C. , Rudin Alfred
Published: March 2009

Purified, gel free butadiene‐styrene copolymers were prepared by emulsion polymerization with butadiene contents of 80, 55 and 30 weight %. Radiation behavior of these materials at 30°C was independent of dose rate in the range 0.04‐0.46 Mrad/hour and the scission‐crosslinking ratio was about 0.40 for all copolymers and was independent of total dose. Extrapolated sol fractions at infinite dose, intrinsic viscosities of irradiated polymers and Mn in the pre‐gel region gave mutually consistent estimates of this ratio. G(crosslink) was 3.4. At the relatively low doses studied, intra‐molecular crosslinking was evident only with the high styrene content polymer. Active sites for intermolecular crosslinking are thought to be allylic to chain double bonds, whereas vinyl groupings may be involved in intramolecular crosslinking.
Potential pitfalls in model discrimination
Authors: Pritchard D. J. , Bacon D. W.
Published: March 2009

Statistical experimental design techniques for model discrimination are evaluated using data obtained by Juusola (1971) for the oxidation of o‐xylene over a vanadium oxide catalyst. The Box‐Hill (1967) design procedure for discrimination is found to be particularly sensitive to underestimation of the variance of the measured response. An analogous weighted criterion is developed and found to perform satisfactorily with data fitted using weighted least squares. Other numerical difficulties encountered in using the discrimination design criteria are also discussed.
Motion of solids in spouted beds
Authors: Van Velzen D. , Flamm H. J. , Langenkamp H. , Casile A.
Published: March 2009

Solids movement in a spouted bed has been investigated by means of a radioactively marked particle technique, using a scintillation counter as a detector.

The average particle velocity in the spout was found to depend on gas flow rate, gas inlet geometry, axial elevation, bed height, and column diameter.

The solids circulation rate is shown to be proportional to the gas flow rate and, further, a function of column and gas inlet geometry, density of fluidising gas and particle diameter.

Empirical correlations for both the particle velocity in the spout and the solids circulation rate as a function of axial elevation, are presented.
Odour control from a kraft mill lime kiln using a spouted bed pre‐drier
Authors: Prakash C. B. , Mathur K. B. , Murray F. E.
Published: March 2009

A study has been conducted on the drying of lime mud and the concurrent oxidation of sodium sulphide in the mud. The experiments were done using a 6″ dia spouted bed of coarse inert particles (cement clinker and limestone; —4 + 10 mesh) with continuous feed of lime mud. A range of inlet gas temperatures, from 260°F to 400°F, was studied. A high degree of sulphide oxidation was achieved by this method over the entire temperature range, sulphide removal being in excess of 80% in all runs and as high as 98% in some.

An analysis of the economic feasibility of drying lime mud in a spouted bed indicates that the process has good potential both as a method for drying lime mud prior to calcining and for control of hydrogen sulphide emission from lime kilns operated at kraft pulp mills.
Application of the parallel disc model for uneven film thinning
Authors: Liem Albert J. S. , Woods Donald R.
Published: March 2009

The use of the parallel disc model is extended to allow for partial mobility of the interfaces to describe thinning at the thinnest point of an unevenly draining film.

Various methods of describing partial mobility are described and compared. The model predicts satisfactorily the observed film thinning (measured by the light interference method) for toluene/water systems containing zero, 10−6M and 10−4M palmitic acid with toluene drops ranging from 0.0025 to 0.005 ml and an anisole/water system with 0.015 ml anisole drop. The trend of change of the calculated partial mobility is consistent with the expected liquid/liquid interface behavior during thinning.
Laminar forced convection in the thermal entrance region of curved pipes with uniform wall temperature
Authors: Akiyama Mitsunobu , Cheng K. C.
Published: March 2009

The thermal entrance region heat transfer problem for fully developed laminar flow in curved pipes with uniform wall temperature is approached by an alternating direction implicit method for the parabolic energy equation for a flow regime with Dean number ranging from 0 to an order of 100. This work represents an extension of the classical Graetz problem in straight tubes to curved pipes. The graphical results for temperature developments in the form of temperature profiles through the horizontal and vertical planes, isothermals and local Nusselt number variations in the thermal entrance region are presented in such a way as to illustrate clearly the interaction between the secondary flow and the developing temperature field for Prandtl numbers of 0.1, 0.7, 10 and 500. For a given Dean number, the effect of Prandtl number is to shorten the thermal entrance length (I/Gz) and the temperature field develops rather rapidly with large Prandtl number. The effect of Dean number is similar to that of Prandtl number with Dean number effect becoming much more appreciable at high Prantdl numbers than at low Prandtl number.
Rates of isotopic exchange between hydrogen and aminomethane catalyzed by potassium methylamide
Authors: Kalra Harish , Otto Fred D.
Published: March 2009

Pseudo first order kinetic constants for the exchange of deuterium between hydrogen and aminomethane were determined from measurements of the rates of absorption of hydrogen deuteride into liquid aminomethane flowing over a sphere. Potassium methylamide dissolved in the amine catalyzed the reaction. Kinetic constants range from 130 to 650 sec−1 at temperatures from —30° to —10°C and catalyst concentrations of 4.95 to 15.8 g K/kg amine.
Shear deagglomeration of solid aggregates suspended in viscous liquids
Authors: Patterson I. , Kamal Musa R.
Published: March 2009

The paper deals with the deagglomeration process in viscous fluids. The process is that in which aggregates of particles suspended in fluids are broken in a shear field. A mathematical model is proposed to predict the equilibrium particle size distribution as a function of shear stress, the initial particle size distribution and the agglomerate strength distribution. Experimental work was performed to test the model. A concentric cylinder apparatus provided the shear field and a procedure was developed to determine the agglomerate size distribution. Artificial agglomerates were prepared by a novel method. Within the limitations of experimental and sampling errors, the calculations agree with experimental results.
Water activity data representation of aqueous solutions at 25°C
Authors: Teng Tjoon‐Tow , Lenzi Fabio
Published: March 2009

Polynomial expressions have been fitted to the complete range of available water‐activity data for 396 electrolyte and non‐electrolyte aqueous binary systems. The standard deviation of regression rarely exceeded 0.001 and was less than 0.0002 in most cases. Such data representation is useful for the prediction of the water‐activity of mixed moderately concentrated aqueous solutions.
Vertical two‐phase flow: Part II. Holdup and pressure drop
Authors: Oshinowo Toks , Charles M. E.
Published: March 2009

Two‐phase gas‐liquid flow has been investigated in a 1‐inch internal diameter vertical tube coil containing two risers and a downcomer all connected by “U” bends. Pressure drop, holdup and flow pattern data were successfully obtained simultaneously in the three vertical tubes, each 17.30 ft. long, for five different air‐liquid systems at about 25 psia and 50°F‐80°F over flow ranges of 0–700 lbmair/min‐ft2and 140‐‐25300 lbmliquid/min‐ft2.

Pressure drops and liquid holdups were plotted against gas volume flowrate with liquid flowrate as a parameter. From these plots it was found that for a combination of an increase in liquid viscosity and density, and a decrease in surface tension, the frictional pressure drop increased in down flow and decreased in upflow. Holdup, on the other hand, increased for both types of vertical flow with respect to the same combination of parameters.

The Lockhart‐Martinelli scheme was satisfactory in correlating frictional pressure drop and holdup in all the flow regimes except the frothy‐slug regime in upflow. In downflow however, the Lockhart‐Martinelli scheme met with limited success because of a strong influence of liquid flowrate, physical properties and pipe orientation.

Holdup in the falling film and falling bubbly film regimes in downflow were satisfactorily treated by the drift flux approach which emphasizes the relative motion of the two phases.
Experimental study of the internal fluid dynamics of forming drops
Authors: Humphrey J. A. C. , Hummel R. L. , Smith J. W.
Published: March 2009

A non‐disturbing photochromic flow visualization technique has been used to study fluid flow conditions within the vertical core region of organic liquid drops growing from a single nozzle in an equilibrated water phase. The indicator 1,3,3‐trimethylindolino‐6′‐nitrobenzopyrospiran (0.015%), which was dissolved in the dispersed phase produced extremely fine tracer lines in the drops when irradiated with UV light from a multipulse nitrogen laser. High speed cinephotographs of the observed time lines were used to estimate axial and radial velocity components by means of a numerical mass balance technique. By substitution in the Navier‐Stokes equations it is shown how the axial and radial pressure change distributions may be obtained from the velocity measurements.
Minimizing the pressure gradients in capsule pipelines
Authors: Ellis H. S. , Kruyer Jan
Published: March 2009

The pressure gradients due to cylindrical capsules were reduced by up to 80% by providing them with plastic instead of steel surfaces or by fitting them with collars. The power requirements of a capsule pipeline depend greatly on the capsule density, and if the capsules were constructed so that a third of the volume consisted of voids, the power needed to transport two teragrammes (2 million tons)/year of solid with a density of 1500 kg.m−3 (S.G. = 1.50) in a 254 mm (10 in.) pipeline would be reduced by over 90%. The pressure gradients and power required to transport spherical capsules were generally much smaller than those required for even the smoothest cylinders of the same specific gravity.
Electrothermal fluidized bed chlorination of zircon
Authors: Manieh Atef A. , Scott D. S. , Spink D. R.
Published: March 2009

Zircon sand, ZrSiO4, is chlorinated in an electrothermally‐heated fluidized bed reactor using calcined petroleum coke as the reducing agent and chlorine as the chlorinating agent. The electrothermally‐heated fluidized bed reactor proved to be versatile and effective for the chlorination of zircon sand.

The rate of the reaction can be expressed by the formula

The reaction was found to be of zero order with respect to the chlorine concentration, which suggests that chlorine is strongly adsorbed on the solid particles; as such, the concentration of chlorine in the gas phase has no effect on the reaction rate.

The activation energy for the reaction was found to be 10.55 Kcal/gram mole which is indicative of control by the rate of a surface reaction or adsorption step.
Kinetics of bio‐oxidation of metal sulphides
Authors: Torma A. E. , Legault G. , Kougioumoutzakis D. , Ouellet R.
Published: March 2009

The microbiological oxidation of cadmium, cobalt, nickel and zinc sulphides has been investigated using a pure strain of Thiobacillus ferrooxidans. Kinetic parameters (Vm and K) have been derived regarding the effect of initial total surface area of these substrates. A relationship is suggested to exist between the rate of sulphide oxidation and the solubility product of the respective metal sulphide.
Laminar natural convection caused by chemical diffusion and reaction from a vertical plane surface
Authors: Meadley C. K. , Rahman M.
Published: March 2009

A theoretical study of laminar natural convection over a semi‐infinite vertical plate is presented. The plate is of given, uniform concentration in some chemical species and convection is induced by diffusion into and chemical reaction with the ambient fluid. Steady state conditions are assumed. The equations used are basically those of the two‐dimensional boundary layer theory, modified to accommodate binary diffusion by Fick's second law, the Boussinesq approximation and homogeneous, irreversible isothermal reaction kinetics. A similarity transform to one variable is possible in the absence of chemical reaction; otherwise the problem is solved by perturbation expansions about an additional similarity variable which is dependent on the reaction rate. It is shown that the Schmidt number Sc and the reaction order n are the two fundamental parameters of the problem. Some analytical and numerical solutions are given for the ranges 10−2≤ Sc ≤ 104and 0 ≤ n ≤ 2. Calculations are presented in the form of graphs showing the concentration and flow fields within the convection layer. Generally it is found that the presence of chemical reaction expands the diffusion and velocity domains out from the plate, resulting in a larger, while less distinct, convection layer.
Heat transfer effects on drying rate of food dehydration
Authors: Vaccarezza Luis M. , Lombardi Jose L. , Chirife Jorge
Published: March 2009

This work studies the consequences of neglecting heat transfer effects in the Fick's law solution of food dehydration problems. A semi‐empirical approach is presented which correlates temperature and moisture changes of sugar beet root during the first falling rate period of drying; while the coupled heat and mass transfer equations are not solved rigorously, the approach gives a fairly accurate representation of the experimental results. An improved analysis through Fick's law is possible when the effect of changing sample temperature is considered.
Additive excess free energy models for predicting gas solubilities in mixed solvents
Authors: Puri P. S. , Ruether J. A.
Published: March 2009

New data are reported for the solubility of hydrogen in the solvent binaries: acetone‐isopropanol, acetone‐cyclohexane, and acetone benzene at 25°C and one atmosphere pressure. Models for predicting mixed solvent Henry's law constants which utilize solvent vapor‐liquid equilibrium data are reviewed, and a new model based on the van Laar equation is proposed. The new data and selected data from the literature are used to evaluate the models. For the six systems tested, the proposed model gives the best results, with the assumption of ideality (Krischevsky equation) being nearly as good.
Capture of monodispersed aerosol particles in a fixed and in a fluidized bed
Authors: Knettig P. , Beeckmans J. M.
Published: March 2009

A study was made on the capture of monodispersed aerosol particles in the size range 0.8 ‐ 2.9 μm, in a screen‐supported fixed bed, and in a fixed and a fluidized bed supported on a grid of low superficial area (0.56%). All beds were composed of glass beads of mean size 425 μm. Relatively high capture efficiency was observed in the grid regions of both fixed and fluidized beds supported in this manner, with relatively lower capture efficiency observed in the vicinity of the screen. Aerosol capture efficiency per unit of bed volume in the body of the fixed beds was not significantly affected by the method of support, and was larger than was the case with the fluidized bed. An estimate of aerosol capture efficiency at the grid jets, based on an equivalent pneumatic transport line concept, was in reasonable agreement with experiment.
Longitudinal mixing in a vibrating‐sieve‐plate column two‐phase flow
Authors: Nemecek Milan , Prochazka Jaroslav
Published: March 2009

Longitudinal mixing in the continuous phase of a vibrating‐plate extractor was examined. Particular attention was focused on the effect of the flow of the dispersed phase, which turned out to be of major importance. Three regimes displaying distinctly different character of longitudinal mixing may be observed. The flow within a stage was studied in detail and it was shown that the stage could split into two regions of different character of the flow. A model was proposed which makes up the total effect of longitudinal mixing from the back flow through the plate plus axial dispersion within the stage. Correlations have been proposed relating the axial dispersion coefficient to the hold‐up and droplet diameter.
Packed extraction columns: A review of correlations for maximum throughput
Authors: Houlihan R. , Landau J.
Published: March 2009

A considerable amount of experimental data on maximum flow rates of countercurrently flowing liquid phases in packed columns has been published and a number of correlations for flooding velocities have been proposed. In the present paper various correlations are tested, using the same set of experimental results selected according to plausible criteria. The results of the test are presented in a consistent manner. Reasons why the result arrived at in this review differ from the recommendation given in Reference 10 are discussed.
Etude expérimentale du micromélange à l'aide d'un traceur non‐réactif dans un réacteur agité
Authors: Truong  , Trong Khac , Methot J.‐Claude
Published: March 2009

On étudic le niveau de micromélange dans un réacteur muni de quatre chicanes et d'un agitateur à turbine à l'aide de la technique d'injection échelon d'un traceur ionique non‐réactif. Une sonde conductimétrique à haute résolution spatiale a été utilisée pour détecter les fluctuations de concentrations résultant de la turbulence. L'approche phénoménologique basée sur la collision et redispersion des agrégats de fluide a été mise en évidence expérimentalement. Une évaluation directe du degré de ségrégation a été effectuée et l'ordre de grandeur trouvé (J varie de 10−3 à 10−5) a indiqué que le réacteur expérimental était à l'état de mélange maximal.
The effects of intraparticle diffusion on the kinetics of gel entrapped enzymes
Authors: Korus R. , O'Driscoll K. F.
Published: March 2009

The results of a theoretical treatment are given for the effect of intraparticle diffusion on the Michaelis‐Menten kinetic behaviour of enzymes entrapped in spherical hydrogel particles. It is shown that curvature in Lineweaver‐Burk plots may be expected, and that the influence of particle size on the activity of entrapped enzymes may be predicted. The effectiveness factor is discussed and analogies with heterogeneous catalysis noted. Experimental results are presented for the hydrolyses of model substrates by gel entrapped trypsin, β‐galactosidase, glucose oxidase and urease which are consistent with the theoretical treatment.
Methods of estimating the water activity of supersaturated aqueous solutions
Authors: Tran Tuong‐Tu , Lenzi Fabio
Published: March 2009

Empirical and semi‐empirical methods of estimating the water activity of supersaturated aqueous solutions at up to twice the saturation molality are compared for CaCl2 and Na2SO4 at °0C and K2SO4, KH2PO4, NaCl, KCl, RbCl, CsCl, KNO3 and mannitol at 25°. An empirical method, applicable to both electrolytes and non‐electrolytes, is described.
The solubility of H2S and CO2 in aqueous monoethanolamine solutions
Authors: Lee J. I. , Otto F. D. , Mather A. E.
Published: March 2009

The solubility of hydrogen sulphide and carbon dioxide, respectively, in 2.5 and 5.0 N aqueous monoethanolamine solutions has been determined at temperatures of 40°C and 100°C. Partial pressures of CO2 ranged from 0.1 to 1000 psia, while partial pressures of H2S ranged from 0.3 to 650 psia. The results have been used, together with literature data, to calculate enthalpies of solution.
Control of a binary distillation column utilizing a simple control law
Authors: McGinnis R. G. , Wood R. K.
Published: March 2009

Multivariable control of overhead and bottoms composition of a binary distillation column subjected to feed flow disturbances has been studied. The study has been performed using a pilot scale column, equipped with overhead and bottoms composition analyzers, operated under the control of an IBM 1800 digital computer. The column dynamic behavior, for control law calculation, was approximated by a two state variable model. Experimental results employing multivariable feedback and multivariable feedforward‐feedback control laws are presented.
Optimization by distributed control of reactors with decaying catalyst Part I: Non‐linear catalyst deactivation
Authors: Therien N. , Crowe C. M.
Published: March 2009

The quasi‐steady state optimization of a single tubular fixed bed reactor with a slowly decaying catalyst is considered.

The optimal choice of temperature T(z, t) distributed in both the space of the reactor and in chronological time is sought so as to maximize the total amount of reaction in a fixed given period of time.

A single irreversible reaction is considered with a rate expressible as a product of separate functions of temperature, activity and conversion. The rate of catalyst decay is also a product of separate functions of temperature and activity but independent of conversion. Upper and lower bounds are placed on the permitted temperature. Theoretical characterization of the optimal policy is obtained using Sirazetdinov and Degtyarev's maximum principle derived for first‐order partial differential equations and the influence of the ratio of reaction activation energy to catalyst deactivation energy on the derived optimal policy is indicated.

Numerical calculations are presented to illustrate the optimal policies.
Simultaneous heat and mass transfer in spouted beds
Authors: Kmiec Andrzej
Published: March 2009

The results of a fluid‐particle heat and mass transfer study in air spouted beds of silica gel and activated coal particles, using a 9 cm I.D. column with a 30° and 90° conical base, are reported. The effects of gas velocity, particle size, bed depth and cone angle on the heat and mass transfer coefficients are discussed. Equations correlating heat and mass transfer coefficients have been established. The ratio (jn)s/(jD)8 has been found to be dependent on the Reynolds number and the system of spouting.
Wall mass transfer in horizontal slurry pipelines
Authors: Postlethwaite John , Holdner D. N.
Published: March 2009

Measurements have been made of the rate of mass transfer of dissolved oxygen to the walls of 5 cm diameter horizontal pipes carrying aqueous slurries of sand and iron ore, in the concentration range 10 — 20 vol % at velocities up to twice the critical value for deposition. The results which show that the suspended particles greatly increase the rate of mass transfer are discussed in terms of the analogies and are compared with the results of previous workers for heat and momentum transfer. In the case of mass transfer in systems with high Schmidt numbers it appears that there is a specific effect of the solid particles relating to the disruption of the viscous sub‐layer.
Electrochemical wall mass transfer in liquid particulate systems
Authors: Smith J. W. , King D. H.
Published: March 2009

Ionic mass transfer coefficients between the wall of a 2.081 inch tube and liquid fluidized beds of lead glass, soda glass and lucite spheres have been measured using the diffusion‐controlled reduction of ferricyanide ion at a nickel cathode for porosities 0.90 to 0.45 and Schmidt numbers 580 to 2100.

The developed fluidization mass transfer coefficient for 41 < DT/dp < 105 were correlated by iD E = 0.274 ReH−0.38 for 10 < ReH <1600 and by JD E = 0.455 ReH−0.44 for 16.7 < DT/dp < 27 and 50 < ReH < 3500. ReH is the hydraulic Reynolds number = dH up/μE and dH is DT E/[1 + (3/2) ((1–E)) (DT/dp)).

The distinct effect of DT/dp ratio is attributed to wall effects and the non‐particulate behaviour of the fluidized bed for DT/dp < 27.

Measurements in the open pipe and packed bed agreed very well with literature values. The packed bed gives highest mass transfer coefficients at given ReH.
SO2 promoted oxidative dehydrogenation of ethylbenzene
Authors: Gaspar N. J. , Vadekar M. , Pasternak I. S. , Cohen A. D.
Published: March 2009

It has been demonstrated that SO2 acts as an efficient dehydrogenation agent in the conversion of ethylbenzene to styrene in the presence of alkali and alkaline earth metal oxide doped alumina and titania catalysts. Development of these catalysts, which give styrene yields of greater than 80% per pass, is described in the paper. The catalysts allow the use of close to stoichiometric amounts of sulphur dioxide, are active in the presence of steam diluent and show low deactivation with time. The effect of varying process conditions such as temperature, reactant concentration and diluent amount is also described.
A concentrated suspension model for the couette rheology of blood
Authors: Brennen Christopher
Published: March 2009

A simple “cell” method for concentrated suspensions has been used to construct a model for the rheological behavioi of blood. The model includes the physical pioperties of the suspending medium, red cell membrane and red cell fluid content. Predictions of the gross viscosity of red cell suspensions are found to agree very well with experiment in the cases of hardened red cells (or normal red cells at very low shear rate) and of normal red cells in the asyniptotic limit of high shear rates. The behavior at intermediate shear rates requires a knowledge of the visco‐plastic properties of the membrane and a number of membrane models are investigated. Of particular interest is a plastic membrane which employs a membrane yield stress obtained from other experiments and whose results are qualitatively in agreement with the viscometric data at these intermediate shear rates.
Phase holdup characteristics of three phase fluidized beds
Authors: Kim S. D. , Baker C. G. I. , Bergougnou M. A.
Published: March 2009

The individual phase holdups in two (liquid‐air, liquid‐solids) and three (liquid‐air‐solids) phase fluidized beds have been measured over a wide range of liquid and gas velocities. Ex‐periments were canied out in a large two‐dimensional bed. Three solids were used ranging in size from 1 to 6 mm.

The effect of viscosity (1‐70 cp) was determined using solutions of sugar and carboxymethyl cellulose of different concentrations. Various acetone‐water mixtures were employed to examine the effect of surface tension in the range 40‐73 dyne/cm.

Beds of particles having a minimum fluidizing velocity in the liquid of less than 1.28 cm/sec were found to initially contract upon the injection of gas. In contrast, beds of particles having minimum fluidizing velocities exceeding tins value were found to expand.
Three dimensional turbulent wall jets
Authors: Narain Jai Prakash
Published: March 2009

Jets issuing tangentially to an impermeable flat surface from orifices of finite aspect ratio are termed three‐dimensional wall jets. The turbulent flow of viscous incompressible fluid associated with such wall jets has been investigated analytically. Results are presented for the wall jets issuing from orifices of various shapes and several aspect ratios. The maximum velocity shows three regions of decay. The potential core region is followed by a characteristic decay region where maximum velocity decays in a manner dependent on the shape and aspect ratio of the orifice. Following this region, there is a radial wall jet type maximum velocity decay region. All three‐dimensional wall jets issuing from any arbitrary cross‐sectional orifice decay in a similar manner in this radial decay region. The half‐velocity width grows faster in the transverse direction than in a direction normal to the flat surface. The analytical results agree reasonably well with existing experimental results.
Activation de la tourbe de sphaigne par le dioxyde de carbone et agglomération du charbon actif produit
Authors: Son P. N. , Khanh P. V. , Chornet E.
Published: March 2009

The physical activation of peat moss using CO2 has been investigated with respect to the operational variables and the characteristics of the active carbon produced. Peat coke is produced during carbonisation with a 30% yield. The activated carbon accounts for 25% of the initial air dried peat moss.

Analysis of the active carbon has revealed a surface area up to 600 m2/g and a chemical reactivity similar to commercial active carbon as measured by the iodine, phenazone and phenol indexes.

The active carbon thus produced is a powdered material, with a weak abrasive resistance. Agglomeration of the carbon and subsequent pelletization has been done with ammonium ligno‐sulfonate, water, and the application of pressure. Resistant pellets can be obtained using 15‐20% lignosulfonate and 3000 psi.
Modified van der waals equation for the dense gaseous and liquid regions from PVT data for methane
Authors: Dingrani J. G. , Thodos George
Published: March 2009

PVT measurements available in the literature for methane in the gaseous and liquid regions were used with the van der Waals equation of state,

to obtain values of the internal pressure parameter, a, where the covolume parameter was taken as b = vc/3. The conditions covered temperatures from 114.53°K (TR = 0.599) to 611°K (TR = 3.20) and pressures up to 3000 atm (PR = 65.50). A dimensionless relationship was developed for the dependence of the parameter a on density and temperature for the gaseous and liquid regions. Density values for methane were calculated from the resulting equation and were compared with the corresponding experimental values to produce an average deviation of 0.26% (791 points). This relationship also enabled the accurate prediction of density values for substances having similar critical compressibility factors as methane (zc = 0.289). For neon and ammonia, this relationship was found to have a limited applicability.
Evaluation of capital cost data: Drives
Authors: Woods Donald R. , Anderson Susan J.
Published: March 2009

Capital cost correlations are given for electric and gasoline motors, steam, gas and combustion‐gas driven turbines, power transmission units and power converters. Correlations available in the literature and current data are compared on a consistent basis. Thirty‐eight graphs show the relative magnitudes of the different correlations and the recommended correlation for each type of equipment is summarized in a table.
The capillary break‐up of a binary liquid column inside a tube
Authors: Mikami T. , Mason S. G.
Published: March 2009

The break‐up of a stationary viscous liquid cylinder surrounded by an immiscible viscous liquid contained in a circular tube by capillary forces at the fluid interface is considered.

It was found that the maximum growth‐rate parameter f* depends upon η'/η, the ratio of the viscosity of the inner liquid to that of the outer liquid and a/S, the ratio of the radius of the inner liquid cylinder to that of the tube. Both f* and corresponding wavelength parameter (2πa/λ)* have been calculated theoretically; measured values of both parameters are in good agreement with the theory.
Comparison of methods for the prediction of liquid holdup for upward gas‐liquid flow in inclined pipes
Authors: Gregory G. A.
Published: March 2009

Three methods for predicting the in situ liquid volume fraction for the upward flow of gas‐liquid mixtures in inclined pipes have been tested against available data from the literature. Combined with the results of an earlier paper, a total of seven methods have been compared.

It is demonstrated that for angles of up to 10°, pipeline inclination has little effect on the predicted holdup. Correlations arc recommended for use under specified conditions.