bluuebunny/crossref_metadata_2025 huggingface dataset:
An investigation of the operating parameters of a low energy wet scrubber for fine particulates
Authors: Douglas P. L. , Dullien F. A. L. , Spink D. R.
Published: March 2009

Tests performed on an inexpensive, low energy wet scrubber are described. The device employs a centrifugal fan, operated at 550–750 rpm, and co‐current spray nozzles producing a relatively fine spray, from 20μ to 180μ. The fan acts as the prime mover of air, as contacting device, agglomerator, and precipitator. Variations in the scrubber's collection efficiency with changes in fan speed, water flow rate, nozzle position and with particle size in the range 0.1–3μ. have been studied.
An experimental study of mass transfer in rotating couette flow with low axial reynolds number
Authors: Strong A.B. , Carlucci L.
Published: March 2009

An experimental investigation has been undertaken to determine the oxygen transfer rate of a rotating Couette flow oxygenator for low axial annular flow rates. The purpose of this study was to determine if such a device might provide a rational basis for the subsequent design of a blood oxygenator for respiratory support in clinical situations. Using oxygen and degassed water as an analog to oxygen and blood the Sherwood number was determined as a function of the axial Reynolds number and the Taylor number. Results show that oxygen transfer rates can be enhanced by at least ten times over that of the non‐rotating situation, the flow being laminar with vortex flow superposed. The present results were correlated as Sh vs. Ta/Tac over the range of parameters studied.
An investigation of oxygen transfer rates to flowing films of various electrolyte solutions
Authors: Raymond Dale R. , Zieminski Stefan A.
Published: March 2009

In this work the mass transfer coefficient for the absorption of oxygen was measured for solutions of K2SO4, (NH4)2SO4, Na2SO4, MgSO4, MnSO4, Al2(SO4)3, NaCl, AlC13 under conditions of nearly horizontal, thin, essentially laminar, flowing films. The results showed a systematically ordered dependence of the mass transfer coefficient on the hydration where the values of the mass transfer coefficient decrease with the decreasing entropy. This effect becomes progressively more pronounced with increasing charge of the cations. Finally, although the entropy of hydration has a strong influence on the changes in the coefficient, it does not have a common linear relationship for the investigated ions.
PVT study of trifluoromethane by the burnett method
Authors: Belzile J. L. , Kaliaguine S. , Ramalho R. S.
Published: March 2009

PVT data for trifluoromethane were obtained by means of a three‐reservoir Burnett cell. Compressibility factors corresponding to seven isotherms (0, 25, 50, 75, 100, 150 and 200°C) were obtained experimentally, encompassing pressures up to 16.5 MPa (2,400 psia). Second and third virial coefficients were calculated for these seven temperatures, and parameters for the Stockmayer potential functions were obtained. The degree of molecular association for trifluoromethane was evaluated by the procedure proposed by Lambert and coworkers. Enthalpy and entropy of dimerization were also estimated.
Interfacial viscoelastic properties of adsorbed surfactant and polymeric films at fluid interfaces
Authors: Mohan V. , Malviya B. K. , Wasan D. T.
Published: March 2009

The viscous and elastic properties of fluid interfaces play an important role in the stability of foams and emulsions as well as in the selection of surfactants for tertiary oil recovery. These properties were determined for aqueous solutions of surfactant, polymer, and polymer plus surfactant systems using a deep channel surface viscometer. The surface rheology of the adsorbed film was represented in terms of the two‐parameter Maxwell model. Depending on the system investigated, the films were found to be either viscoelastic, purely viscous, neither viscous nor elastic, or rigid.
The role of paraffin wax in the formation of minor products in the catalytic cracking of petroleum distillates over la‐y
Authors: John Thomas M. , Wojciechowski Bohdan W.
Published: March 2009

An investigation of the role of paraffin wax in the catalytic cracking of wax‐bearing petroleum distillates has been carried out in a fixed‐bed reactor containing La‐Y catalyst over a temperature range from 482° to 524°C.

By using the concept of initial product selectivity derived from the time‐on‐stream theory of catalyst decay, it was found that increasing the wax content of the feedstocks resulted in an increase in the yield of C5+ gasoline and a decrease in the yields of most of the gaseous products and of coke. Ethane and propylene and the olefin content of the gasoline increased in yield with the addition of wax. The mixing of cracking feedstocks has only a linear effect on the reactivity and no synergistic effects in any of the observed properties of the reaction are in fact observed.
Additivity rules for the prediction of the density of aqueous solutions containing mixed‐type solutes
Authors: Teng Tjoon‐Tow , Sangster James , Lenzi Fabio
Published: March 2009

Densities of ternary aqueous solutions of mixed‐type solutes have been measured at 25°C to high concentration. Two methods, the one isopycnotic (same density) and the other based on ionic strength, have been used to predict the densities of these solutions. The isopycnotic method proved to be the more accurate.

The two methods have been applied in reverse to calculate densities of supersaturated binary aqueous solutions of NaCl and KCl. The methods give concordant results for each salt Deviation parameters for the methods are presented, with a discussion of their use.
Optimal inlet temperature control of reactors with catalyst decay
Authors: Gruyaert F. , Crowe C. M.
Published: March 2009

The constant conversion policy which has been shown to be optimal in certain classes of optimal control problems for reactors with decaying catalyst is examined here for the inlet temperature control in a tubular reactor where the catalyst decay is a function of the composition. A single irreversible reaction is considered where the rate expression is a product of separate functions of temperature, concentration or conversion and catalyst activity. The catalyst decay rate expression is also a product of separate functions of the same variables. A proof of the constant exit conversion property is given for problems where the decay rate is of first‐order with respect to the catalyst activity.
Bubble swarm characteristics in bubble columns
Authors: Kumar Akhilesh , Degaleesan T. E. , Laddha G. S. , Hoelscher H. E.
Published: March 2009

New correlations have been proposed for estimation of gas phase holdup, characteristic velocity, interfacial area for mass transfer and mean bubble size of bubble swarms under dispersed and fluidized operation of bubble columns employing single — and multi‐orifice distributors. The analysis of results include available literature data of other investigators.
Low peclet number heat transfer in the thermal entrance region of parallel‐plate channels with unequal wall temperatures
Authors: Wu Ray‐shing , Cheng K. C. , Ou Jenn‐Wuu
Published: March 2009

The problem of low‐Peclet‐number thermal entry heat transfer for plane Poiseuille flow in parallel‐plate channels with uniform but unequal wall temperatures is approached by the eigenfunction expansion method utilizing the Gram‐Schmidt orthonormalization procedure. The formulation considers axial heat conduction and allows upstream heat penetration through the thermal entrance. Numerical results are obtained for the case with entrance condition parameter θ0 = 1 and Peclet number Pe = 1, 5, 10 and 50. The effect of Peclet number on temperature distributions in both upstream and downstream regions is studied. At Pe = 50, the concept of thermal boundary layer is applicable and the present series solution does not yield physically reasonable temperature distribution locally near the upper plate at the thermal entrance. The difficulty may be attributed to the nature of thermal boundary conditions at the thermal entrance and the transition from elliptic problem to parabolic problem with the increase of Peclet number.
Rising behavior of air bubbles in superposed liquid layers
Authors: Mori Yasuhiko H. , Komotori Kazunari , Higeta Kazuya , Inada Junji
Published: March 2009

An air bubble that passes through a horizontal interface from a lower layer of Freon‐113 to an upper layer of aqueous glycerol forms a two‐phase bubble in the upper layer as a result of entrainment of a certain volume of Freon‐113 from the lower layer. The volume of entrained Freon‐113 and the rise velocity of such a two‐phase bubble have been measured. The former increases with an increase of the bubble size irrespective of the viscosity of the upper liquid. The latter is somewhat lower than that of a normal air bubble of the same size.
Comparison of methods for measuring interfacial areas in gas‐liquid dispersions
Authors: Landau J. , Boyle J. , Gomaa H. G. , Al Taweel A. M.
Published: March 2009

Interfacial areas were determined for gas‐liquid systems in a column with transparent walls by the chemical and two physical methods: photography and light attenuation. The advantages of the different methods are discussed and improvements in the physical methods are described. By using a Data Tablet Digitizer, the photographic technique provides additional information on the gas dispersion without increasing the amount of work needed for analysis of the photographs. Use of the light attenuation technique is extended to conditions when multiple scattering and stray light must be taken into account; it can then be used up to values of optical path densities equal to 80.
An explanation for an apparent failure of the box‐hill procedure for model discrimination
Authors: Bajramovic R. , Reilly Park M.
Published: March 2009

Froment and Mezaki made an early attempt to verify, by using real experimental results, that the Box‐Hill procedure could accomplish more efficient model discrimination than less sophisticated procedures. They found rapid convergence but the conclusion varied, depending on the conditions of the initial experimental trials. In attempting to remedy this inconsistency several workers have found changes in the Box‐Hill method which can eliminate it. In this investigation an explanation of the failure is sought and found in terms of the requirements of the method. It is shown that direct application of the unmodified procedure is successful if the dependent variable is chosen so as to minimize the effect of errors in the independent variables even though this means changing the form of the model from linear to nonlinear in the parameters.
Heat transfer to laminar flow with temperature — dependent heat generation
Authors: Mori S. , Inoue T. , Tanimoto A.
Published: March 2009

Two problems were solved theoretically on the heat transfer to circular tube flow with internal heat source. The one problem is to maintain the mixed‐mean temperature of fluid at the inlet temperature. The other is a conjugated problem with a uniformly specified temperature at the outside surface of the wall, accounting for the wall conduction.

From the numerical example for the former, it is shown that the mixed‐mean temperature can be controlled within 15% error under the estimated condition.

From the numerical results for the latter, it is concluded that the influence of wall conduction is more serious than the case without heat generation.
Continuous multi‐particle crystal growth in vertical cones
Authors: Ishii Tsutomu , Fujita S. , Johnson A. I.
Published: March 2009

Equations of continuity and motion for dispersed two‐phase flow with phase growth are derived and a one‐dimensional steady state solution of these equations is obtained for the design and operation of a vertical cone as a continuous crystallizer. This solution is verified by semi‐continuous and continuous crystal growth experiments. Cones having divergence angles below about 7° were found to be suitable as continuous classifying crystallizers and an approximate flooding range was found.
Effects of surface active agents on fall velocities of drops
Authors: Skelland A. H. P. , Huang Y‐F
Published: March 2009

Terminal velocities of drops undergoing mass transfer were measured in nine systems containing anionic, cationic, or nonionic surfactants. Variables included drop size, formation time, number of parallel droplet‐streams, and surfactant concentration. Results were interpreted in terms of visually observed internal circulation and oscillation of the drops and some success was achieved in correlating the data obtained.
Experimental analysis of particle deposition on single collectors
Authors: Rajagopalan R. , Tien Chi
Published: March 2009

Experimental studies of particle deposition from liquid suspensions of monodispersed particles flowing past single spherical collectors were carried out and compared with theoretical results based on trajectory calculations. The experimental observations indicate the significant effect of particle flocculation and thus suggest the importance of sedimentation as a collection mechanism. The agreement between the theoretical results and the experimental data is good when the surface force interactions are favorable for collection. However, when the electrokinetic repulsion dominates in the neighborhood of the collector, the rate of collection drops rapidly, although not to zero as predicted by theory.
Solving multicolumn equilibrium stage operations by total linearization
Authors: Browne Denis W. , Ishii Yoshikazu , Otto Fred D.
Published: March 2009

An efficient, reliable and easily programmed method for solving systems of equilibrium stage separation devices is described. The method is an extension of an algorithm developed by Ishii and Otto(9) for single columns. It solves all equations simultaneously, takes advantage of the basic tridiagonal matrix form form of the linearized steady state equations and can handle configurations which include distillation columns, absorbers and reboiled absorbers. The solution for a thermally coupled distillation system is presented.
The history and status of research in fouling of heat exchangers in cooling water service
Authors: Suitor J. W. , Marner W. J. , Ritter R. B.
Published: March 2009

A review of research in fouling by cooling water is presented. The literature survey covers the period from 1924 to the present. Both theoretical and experimental papers are reviewed, and the more important of these studies are categorized in table form. Significant contributions are discussed with respect to theoretical developments and experimental apparatus as well as operating variables such as velocity, temperature, water chemistry, and material effects. An assessment of the current status of cooling water fouling is made, and several areas for future research are suggested.
Measurements of flow characteristics in a confined vortex flow
Authors: Bank Nader , Gauvin W. H.
Published: March 2009

A study of air flow patterns by hot‐wire anemometry is reported for a vortex chamber consisting of an upper cylindrical section 122 cm in diameter and 61 cm high and a conical bottom section 122 cm high. Quantitative data are presented for flow angles, profiles of mean tangential and axial velocities, and radial distributions of tangential and axial intensities of turbulence as a function of air entrance velocities of 1.6, 2.4 and 3.2 m/s, and axial distance from the top of the chamber.

In general, the quantitative results confirm the theoretical predictions and the experimental trends reported in the literature. In particular, they fully support the conclusion that the flow pattern is relatively insensitive to the entrance volumetric flow rate.

A generalized correlation is presented for the axial velocity distribution. Preliminary correlations are also presented for the tangential velocity distributions in the core and in the annular region of the vortex near the wall. These were found to be functions of the axial location and of the air entrance velocity.
Wall to liquid mass transfer in fluidized beds
Authors: Storck A. , Coeuret F.
Published: March 2009

The paper reports a study of the influence of particle motion on wall to liquid mass transfer in liquid fluidized beds. Results obtained in classical fluidized beds are compared with those observed with expanded fixed beds of the same particles and having the same mean porosity. It is shown that the particle motion has no measurable influence. The particles only act as obstacles to the fluid flow in the same way as if they were fixed in their mean statistical positions.
Generalized treatment for the vapor pressure behavior of polar and hydrogen‐bonding compounds
Authors: Gomez‐Nieto Mateo , Thodos George
Published: March 2009

The vapor pressure behavior of 25 polar compounds, including water and a number of alcohols, has been analyzed and subjected to a generalized treatment using the relationship,

for a total of 1343 experimental measurements presented in the literature and covering the range included between their respective triple points and critical points. For each of these compounds, the parameters of this equation were established using a nonlinear regression numerical technique. The parameters resulting from this regression reproduce vapor pressures for all these polar compounds with an average deviation of 0.44 percent (1343 points).

To extend the application of this vapor pressure relationship, the original parameters of these polar substances were correlated with their respective basic physical properties M, Tc, Pc and Tb. The resulting generalized parameters reproduce vapor pressures with an average deviation of 1.44 percent (1343 points) for all these polar and hydrogen‐bonding compounds. This generalized correlation can be applied for the reliable prediction of vapor pressures for polar substances for which inadequate information is available.
Spherical agglomeration in a conical drum
Authors: Sparks B. D. , Meadus F. W.
Published: March 2009

The spherical agglomeration process is a means of size enlargement in which agitated particles, suspended in a liquid, are bonded together by a second liquid, which will wet the solid surfaces and be immiscible with the suspending medium. A process is described in which agglomeration takes place in a cone shaped vessel, rotating horizontally about its symmetric axis. The cone configuration of the agglomerator imparts a longitudinal impulse to the charge, which is most effective on the largest particles. This causes a size classification within the cone, with the largest agglomerates congregating at the base. The result is the continuous production of uniformly sized, highly spherical pellets. The factors affecting agglomerate growth and size are outlined and discussed.
Diffusion in tabletted catalysts
Authors: Jury Stanley H.
Published: March 2009

A two pore size model is proposed with random arrangement of the dispersed phase (s) and the transient solution and steady state equivalent diffusivity are presented for three new cases. These involve “open micropores,” “blind microprocess” and a combination of the two kinds.

The results reveal modeling inconsistencies in the recent literature. The quasi‐steady state is discussed in relation to this phenomenon.

A new technique of data analysis involving a combination of transient and steady state methods is proposed. This subjects the transient solution to a much more strenuous test.

The results also apply to “barrier” materials.
Contraction de bulles de vapeur non sphériques
Authors: Delmas H. , Angelino H.
Published: March 2009

An experimental study of steam vapour bubble collapse in water suddenly pressurized is performed by use of high speed cinematography. Bubbles with initial radii ranging from 0.14 cm to 1 cm are presented. The pressure difference ranges from 21.7 to 80.8 kPa and the corresponding degrees of subcooling are 6.6°C to 40.9°C.

The experimental data are compared with various theories. Heat transfer between the bubble and the surrounding liquid is underestimated while liquid inertia is more accurately evaluated. This underestimation apparently caused by the distortion of rising bubbles has a great effect on the large bubbles and on low subcooled cases.
Étude des régimes d'évolution thermique de couches fluidisées gaz‐solide mécaniquement agitées
Authors: Rios G. , Gibert H.
Published: March 2009

In the present paper the authors propose a pattern of calculation permitting to predict the thermal evolution of a gas‐fluidized system, which is mechanically stirred and subjected to abrupt fluctuations of the speed of the agitator. The two following cases are studied:

a full‐fluidized system.

a partly‐fluidized system involving a dense portion of wall layer.

The present work permits to confirm the results obtained from the mechanical and thermal studies performed in a steady state(1,2); it also gives a valuable tool for designing automatic control systems intended for regulating the temperature of heterogeneous layers.
Mass transfer and hydrodynamic characteristics of gas inducing type of agitated contactors
Authors: Joshi J. B. , Sharma M. M.
Published: March 2009

Power consumption, rate of gas induction (Q), fractional gas hold‐up and mass transfer characteristics of 0.41, 0.57 and 1.0 m i.d. gas inducing type of agitated contactors were studied. The power consumption was measured by a torque table. The values of effective interfacial area (a), and liquid side mass transfer coefficient (kLa) were obtained by using chemical methods. Two types of impellers (pipe and flattened cylindrical) were employed. The impeller speed was varied from 3 to 11.7 r/s.

The effects of impeller diameter, baffle position, orifice area on the impeller, number of impeller blades, position of impeller from the bottom and liquid submergence on the values of Q and a were investigated. Further, the effect of liquid viscosity and surface tension on the values of Q was studied.

A satisfactory agreement was found between the observed and the predicted value of the minimum impeller speed at which gas induction occurs. The performance of the gas inducing type of agitated contactor has been compared with the conventional mechanically agitated contactor.
Prediction of drop diameter, hold‐up and backmixing coefficients in liquid‐liquid spray columns
Authors: Horvath M. , Steiner L. , Hartland S.
Published: March 2009

The available literature data for the drop diameter, hold‐up and backmixing coefficients were tested experimentally in a pilot plant size spray column. For all these parameters correlations were found which gave results in agreement with the experimental data so that reasonable prediction is possible. Different equations were compared and the ones giving the best fit are recommended.
Hydrodesulphurization of thiophene over a NiO‐MoO3‐Al2O3 catalyst
Authors: Kawaguchi Y. , Lana I. G. Dalla , Otto F. D.
Published: March 2009

NiO‐MoO3‐Al2O3 based hydrodesulphurization catalysts appear to be of long term interest in the processing of Athabasca bitumen to eliminate organo‐bonded sulphur and nitrogen‐containing groups. This study employs such a catalyst (NALCO NM 502: 2% NiO, 14.0% MoO3, and γ‐Al2O3) in rate measurements of the vapor‐phase reaction of thiophene with hydrogen using an integral fixed‐bed reactor operated at about atmospheric pressure and in the temperature range, 270 to 350°C. Both power‐law and mechanistic models were fitted to the data; discrimination amongst the later being based upon consistency with physicochemical observations and the power‐law behaviour. The kinetic parameters for these models were contrasted with those obtained by a number of other workers for primarily Co‐Mo‐Al2O3 catalysts.
Colour removal from kraft mill caustic extraction effluent using aluminum and iron
Authors: Nasr M. S. , Macdonald D. G.
Published: March 2009

The highly coloured compounds found in the caustic extraction effluents of kraft mill bleach plants can be removed by chemical reaction with trivalent metal ions (Me3+). At pH 2.8, these ions react stoichiometrically with carboxylic acid groups (A−) on the lignin compounds to form moderately soluble MeA3 salts. Above pH 2.8, hydroxyl ions compete with the A− groups to form highly insoluble hydroxy metal salts. Maximum colour removals of 99.6 and 98.8% were obtained for an effluent containing 12000 APHA colour units treated with 7 mol/m3 of Al3+ at pH 5.0 and Fe3+ at pH 3.3, respectively.
Cryogenic recovery of tar from athabasca tar sands
Authors: Welmers A. , Bergougnou M. A. , Baker C. G. J.
Published: March 2009

Cryogenic recovery of tar from Athabasca tar sand could be an attractive alternative to the conventional hot water separation process. It is based on the fact that when frozen tar sand is ground, distinct particles of tar and sand are obtained and can be separated by elutriation. A specially designed fluidized bed grinder was developed for operation at temperatures in the range −30 to −130°C. Preliminary experiments have shown that 88% of the tar can be removed from the sand. Improved results can be expected after further optimization of the unit.
Bulk and interfacial physical properties of aqueous solutions of sodium lauryl sulphate and lauryl alcohol with air and benzene systems: Part II — mixed aqueous solutions of sodium lauryl sulphate and lauryl alcohol
Authors: Vijayan S. , Woods Donald R. , Vaya Helene
Published: March 2009

The pH, density, bulk viscosity and electrical conductivity of aqueous solutions of mixtures of sodium lauryl sulphate and lauryl alcohol were measured for a range of concentrations at 25°C. The influence of interface age on the interfacial tension of mutually saturated benzene/aqueous solution surfaces is also reported. The effect of impurities on various physical properties was illustrated using an impure lauryl sulphate system. A detailed comparison of these data with those reported in the literature shows satisfactory agreement above the critical micelle concentration of the sodium lauryl sulphate in water. Current data in the premicellar concentration range reveal anomalous behavior.

Data reported in the literature are summarized for the pH, density, bulk viscosity, electrical conductivity, surface tension, interfacial tension with benzene, surface excess concentration, surface shear viscosity, critical micelle concentration and molecular complex formation of the sodium lauryl sulphate/lauryl alcohol aqueous solutions. The interactions of the anionic‐nonionic surfactants at fluid/fluid surfaces and their influence on the physical properties are examined. The use of such systems in the stabilization of dispersions is also discussed. Eighty‐five references are cited.
Minimum fluidization velocities in beds of mixed solids
Authors: Vaid R.P. , Gupta P. Sen
Published: March 2009

The fluidization behaviour of a bed of solids of mixed sizes and/or densities indicates that for a range of velocities between ubf (the velocity of beginning of fluidization) and utf (the velocity of complete fluidization), such a bed is only partially fluidized. The phase diagrams of these systems show that the phenomenon is analogous to the fractional crystallization of a multicomponent solution and it can find use in selective classification of solids.

In the present work, data on ubf and utf for liquid fluidized beds of two, three, four and five component mixtures have been processed along with those reported earlier on gas‐solid systems, to yield useful correlations for their prediction.
Data and models for flow distribution and pressure drop in spouted beds
Authors: Epstein N. , Lim C. J. , Mathur K. B.
Published: March 2009

A critical examination is made of the approaches used by recent investigators to the prediction of fluid flow distribution and pressure drop in spouted beds. Mathematical models are assessed both with respect to their theoretical validity and their agreement with experiment. Some of the models are rationally modified in order to increase their theoretical acceptability and their conformity to experimental observation. New experimental data on both flow and pressure distribution are presented. Desirable directions for future research are indicated.
Sub‐optimal control of a multivariable non‐linear chemical reactor using quasilinearization
Authors: Litchfield R. , Locke A.
Published: March 2009

The performance of a multivariable non‐linear stirred tank chemical reactor has been used to compare the practicability of an optimal controller and two types of suboptimal controller. The optimal controller, which by its nature required lengthy calculations, was suitable for open‐loop control only and therefore sensitive to modelling errors. By contrast a suboptimal controller, which used the method of quasilinearization to solve the two point boundary value problem, needed only a small amount of computation time and was capable of online implementation. This controller was much less sensitive to modelling errors, and also had the advantage of decoupling the control variables. An extension of this controller incorporated a feedback feature which compensated further for modelling errors and, in addition, unmeasured disturbances. This controller, which is expected to be of interest to the process industries facing inaccurate‐model problems, produced responses close to the true optimal response even when the actual model used was in gross error.
Vortex formation in stirred draining vessels
Authors: Hayduk Walter , Neale Graham
Published: March 2009

When water was rotated by means of a “horse‐shoe” stirrer in a vertical, cylindrical tank and a stream was withdrawn from the bottom through a central exit pipe, a pronounced filament‐like vortex was formed under certain conditions. Experiments were performed to determine the factors which influenced the height of the vortex. The effects of vessel sue, stirrer geometry, rotational speed, exit flow rate and exit pipe diameter on vortex depth were studied. It was found that the vortex depth was highly dependent on the rotational speed, exit flow rate and exit pipe diameter. It was also found that under certain flow conditions the vortex penetrated the exit pipe. A relationship between the vortex depth and the pertinent variables was developed using dimensional analysis. The relationship resulting from a regression analysis of the dimensionless groups affecting the vortex depth was found to be:

Motion picutes were taken showing the flow characteristics in the vicinity of the vortex by using a dye tracer technique. Ways of inhibiting vortex formation were also examined.
Gas‐liquid equilibria in mixtures of hydrogen and thianaphthene
Authors: Sebastian H. M. , Simnick J. J. , Lin H. M. , Chao K. C.
Published: March 2009

Gas‐liquid equilibrium conditions in binary mixtures of hydrogen and thianaphthene were experimentally determined at temperatures of 190 to 430°C and pressures to 250 atm in a flow apparatus. The same apparatus was also employed to measure the vapor pressure of thianaphthene. Comparisons of the new mixture data with Chao‐Seader and Grayson‐Streed correlations show that both correlations predict the thianaphthene equilibrium ratios well but are in error by up to about 45 and 35% respectively for K‐values of hydrogen.
Influence of operating parameters on selectivity in a separation process by liquid membrane permeation for the system styrene‐ethylbenzene
Authors: Alessi P. , Canepa B. , Kikic I.
Published: March 2009

An experimental comparative analysis of various factors involved in the separation of styrene‐ethylbenzene mixtures by liquid membrane permeation was performed.

The choice of the proper surfactant and the influence of the ratio surfactant/solvent/feed and of the operating parameters were investigated.

An attempt is made to interpret the experimentally determined characteristics of the system on the basis of a diffusive model adapted to this kind of separation.
Kinetics of adsorption in bi‐porous molecular sieves. Part II: Comparison of theory and experiment for batch systems
Authors: Lee Lap‐Keung , Yucel H. , Ruthven D. M.
Published: March 2009

Experimental kinetic uptake curves for two sorbates (cis‐2‐butene from the gas phase and n‐heptane from the liquid phase) have been measured in a variety of 5A molecular sieve pellets. Conditions were selected to fulfil either the linear isotherm approximation of the Ruckenstein(3) model or the rectangular isotherm approximation of the preceding paper. For these systems both macropore and micropore diffusional resistances are significant and it is shown that the theoretical models provide a satisfactory interpretation of the experimental uptake curves. Time constants for both macropore and micropore diffusion, calculated by matching experimental and theoretical uptake curves, are consistent with independently measured values.
Extension of the pitzer correlation for compressibility factor calculations
Authors: Hsiao Yuh‐Jen , Lu Benjamin C. Y.
Published: March 2009

The three‐parameter generalized correlation of Pitzer et al (1955) for calculating the compressibility factor Z of normal fluids in the Tr and Pr regions of 0.8 ≦ Tr ≦ 4.0 and 0 ≦ Pr ≦ 9.0 has been extended to wider ranges, using the P‐V‐T data available in the literature for 53 compounds with a total number of data points about 15,000. The linear equation in ω proposed by Pitzer et al is found to be adequate. Values of Z(0) and Z(1) of the linear equation are presented in tabular forms at regular intervals of Tr and Pr in the region of 0.2 ≦ Tr ≦ 5.0 and 0 ≦ pr ≦ 12.0. Quantum gases and highly polar compounds are not included in the correlation.

In comparison, volumetric data for 15 compounds were used as the basis for the correlation of Pitzer et al, while 4 compounds were used by Lee and Kesler. The ω values covered in this work (–0.002 to 0.9065) is also wider than those used by Pitzer et al. (–0.002 to 0.352) and Lee and Kesler (0.0072 to 0.4902). The overall average absolute deviation between the calculated Z values obtained from the proposed correlation and the literature values for the 12 compounds tested by Lee and Kesler is 1.38%, which reduces to 1.07% if 1‐pentene is excluded in the comparison. The corresponding deviations obtained from the correlation of Lee and Kesler are 1.41% and 1.35% respectively. The proposed correlation also yields better results at ω = 0 than those obtained from earlier correlations.
Time‐dependent shear flow of artificial slurries in coaxial cylinder viscometer with a wide gap
Authors: Horie Michihiko , Pinder Kenneth L.
Published: March 2009

An experimental method was developed for characterizing time‐dependent slurries of elongated particles in a coaxial cylinder viscometer which has a wide gap between the inner rotating cylinder and the stationary cup. A model slurry system was studied; it consisted of a dispersed phase of regularly sized nylon fibres and a dispersing medium of an aqueous solution of polyethylene glycol with dextrose and sodium chloride, each of whose effects on the time‐dependent nature of the slurry could be examined.

It was found that only a part of the gap between the cylinders of the viscometer flows under shear, and that the thickness of the flowing layer increases with time and approaches an equilibrium value.

An empirical reaction‐rate type model was constructed for the time‐variation of the thickness of the flowing layer. A second order‐zero order reversible reaction model fitted the experimental data well. The fitting parameters of the model were correlated with slurry variables.
Prediction of mean drop size in batch agitated vessels
Authors: Gnanasundaram S. , Degaleesan T. E. , Laddha G. S.
Published: March 2009

A correlation is proposed for prediction of mean drop size in agitated vessels in the two major hydrodynamic regimes of importance as observed in this study covering a wide range of holdup from 0.01 to 0.5 and impeller Weber numbers from 35–200,000.
Flooding and axial dispersion in reciprocating plate extraction columns
Authors: Hafez M. M. , Baird M. H. I. , Nirdosh I.
Published: March 2009

The flooding and axial mixing characteristics of a 15 cm diameter reciprocating plate extraction column with six different plate arrangements handling kerosene dispersed in water are reported. A general correlation for flooding in the emulsion flow regime is developed and applied to the present results and to published data on other columns and systems. Under certain conditions of flow and agitation, the axial mixing is very high because of circulation, but it can be reduced by including baffles in the plate stack.
Enhanced oil recovery using lignosulfonates
Authors: Bansal Bharat B. , Hornof Vladimir , Neale Graham
Published: March 2009

The effects of lignosulfonates on the recovery of oil from porous media were investigated using unconsolidated Ottawa sand saturated with Fuel Oil No. 4. Displacement tests were conducted for both secondary and tertiary strategies. At 1 Pore Volume injection the additional secondary recovery, relative to that obtained with water‐flooding, varied between 1.3% and 8.5% for 1% and 10% lignosulfonate solutions respectively. The additional tertiary recovery for previously waterflooded sand was found to be 4.5% for 2 Pore Volumes injection of 1% lignosulfonate solution, and showed no increase with increasing concentration. Based on this preliminary work, lignosulfonate solutions would appear to be worthy of further attention in enhanced oil recovery studies.
The effects of mass transport and chemical reaction on pollutant removal in a three‐phase slurry adsorber‐reactor
Authors: Sylvester Nicholas D. , Laribi Sadek , Von Rosenberg Dale U.
Published: March 2009

The analysis of the effects of mass transport and chemical reaction on pollutant removal from a gas‐phase in a three‐phase slurry adsorber‐reactor is presented. A mathematical model, consisting of four coupled differential equations, was developed to describe the process and solved numerically. The modeling assumptions included: perfect mixing in the three‐phase slurry, Henry's law, a linear adsorption isotherm and a second order, irreversible chemical reaction. The model was found to adequately represent limited existing experimental data and to qualitatively predict the effects of the various transport coefficients on the pollutant removal efficiency of the process. The model was also used for design analysis. Although the model‐process achieved significant pollutant removal for representative operating conditions, the percent removal was ultimately limited by mass transport from the gas bubbles to the liquid slurry.
Reactions of ethylene oxide and ethanol in the presence of amberlyst 15: Products and product rate modeling
Authors: Yamanis John , Patton Bradley D.
Published: March 2009

The reactions of ethylene oxide and ethanol catalyzed by Amberlyst 15 (H+) were studied at 60°, 90°, and 120°C. The concentration ranges investigated at 90°C were 0.9–5 and 0.3–6 mol/1 for the oxide and ethanol, respectively, while the mass of resin taken was in the range of 60 to 28 g.

It was found that ethylene oxide reacts with the sulfonic acid groups of the resin to form polymeric ester species which cause catalyst deactivation. Despite the deactivation several reactions occur at 90°C yielding 2‐ethoxyethanol, 2‐(2‐ethoxyethoxy)‐ethanol and 1,4‐dioxane. Two parallel reaction paths and the overall rate model r = r = C1C2C3/(β1C + β2C2) are proposed for the formation of 2‐ethoxyethanol. A back‐biting mechanism is tentatively proposed for the formation of 1,4‐dioxane from the polymer ester species and the model r = βC3 for its rate of formation.
Foam fractionation of spent sulphite liquor: Part I: Separation of surfactants
Authors: Zajic James E. , Berk Dimitrios , Behie Leo A.
Published: March 2009

The surface activity of spent sulphite liquor (SSL) and the separation of surface active components by foam fractionation were studied. The maximum activity (lowest surface tension) of SSL was observed at a high pH. The surface tension was found to be 42 mN/m and 38 mN/m at acidic and basic pH values, respectively, and also a maximum foaminess (Σ) of 7 min was observed at pH 10. Foam fractionation reduced the surfactant concentration by 90% at an optimum pH of 10. The surfactants were concentrated in the collapsed foam as shown by the fact that the critical micelle concentrations of the unfractionated SSL and foam were 70% (v/v) and 10% (v/v), respectively. The removed surfactants were concentrated in 20% of the original liquid volume.
A chromatographic study of the diffusion of N2,CH4 and binary CH4‐N2 mixtures in 4A molecular sieve
Authors: Ruthven Douglas M. , Kumar Ravi
Published: March 2009

The kinetics and equilibrium of sorption of CH4, N2 and binary CH4–N2 mixtures in 4A molecular sieve have been studied by a chromatographic method. The equilibrium isotherms and zeolitic diffusivities, determined with a helium carrier, show good agreement with previous gravimetric data. Counter‐diffusion in the binary adsorbed phase was investigated using a mixed carrier gas and following the response to a small step change from a previously established equilibrium position. The dynamic response curves for the binary system could be satisfactorily interpreted on the assumption that both components in the mixture diffuse independently with the same intrinsic mobilities as for the single component systems.
Evaluation of capital cost data: Liquid moving equipment
Authors: Woods Donald R. , Norman Suzanne L. , Anderson Susan J.
Published: March 2009

Capital cost correlations are given for liquid moving equipment. Correlations available in the literature and current data from suppliers, contractors, consultants and industry are compared on a consistent basis. Forty‐three graphs show the relative magnitudes of the different correlations, and the recommended correlation for each type of equipment is given. Some factors are given on the costs of installing liquid moving equipment.
Residence time distribution in a liquid flowing cocurrently with a gas through a packed bed
Authors: Stepanek J. B. , Achwal S. K.
Published: March 2009

Measurement of response curves to an imperfect pulse signal were carried out in a liquid flowing cocurrently with a gas at two positions in a packed bed. Three types of ceramic packing were investigated, viz. spheres, solid cylinders and Raschig rings, all of nominal size 6 mm. The liquids used were water and a corn sugar solution of viscosity 9.13 mPa·s. The curves were analyzed by means of two models: the axially dispersed plug flow model and the Markov chain model; the latter was solved for this purpose. Empirical correlations for the model parameters were obtained.
Numerical modeling of thermal effects in turbulent mixing of large flows
Authors: Nahavandi A. N. , Holder G. D. , Borhani M. A.
Published: March 2009

A numerical approach for the modeling of thermal effects in turbulent mixing of large flows with uniform eddy viscosities and eddy diffusivities is presented. The distinctive features of this approach are the simultaneous compliance of mass and momentum equations, and accurate predictions of the surface waves and pressure distribution in flow fields with arbitrary bottom geometry. The numerical approach employs centered three‐point finite difference expressions for the first and second spatial derivatives with unequal mesh size and a forward time integration. Numerical stability analysis of the governing equations is utilized to select optimum space and time increments for numerical integration.
Dropwise condensation of different steam‐air mixtures on various substrate materials
Authors: Abdul‐Hadi M. Issa
Published: March 2009

Dropwise condensation of different steam‐air mixtures on three substrate materials (copper, aluminium and nickel) is studied. For each steam‐air mixture, the heat flux, the heat transfer coefficient and the surface temperature are observed to be highest on copper and lowest on nickel substrates for the same identical test conditions. The above heat transfer variables are related to the bulk properties of the substrate.

It is concluded that the presence of non‐condensable gases is an inhibiting influence on the heat transfer performance in the condensation of steam. The normalized variables \documentclass{article}\pagestyle{empty}\begin{document}$ \frac{{h_i \left(\eta \right)}}{{h_i \left(o \right)}} $\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$ \frac{{T_{si} \left(\eta \right)}}{{T_{si} \left(o \right)}} $\end{document} are found to be functions of the air concentration only.
An analytical investigation into dropwise condensation of different steam‐air mixtures on substrates of various materials
Authors: Abdul‐Hadi M. Issa
Published: March 2009

A mathematical model has been developed from the kinetic theory of gases. The model accounts for the heat transfer performance during dropwise condensation of different steam‐air mixtures on surfaces of various materials. In the development of the analytical model, the droplet surface is assumed to be in equilibrium or very near to equilibrium conditions with the fluid in contact, whereas the steam at the liquid‐vapour interface is visualized to be in the saturated state. It is concluded that a minute fraction of the part of the substrate surface covered by liquid droplets (the minute fraction is referred to as the effective area) is most effective for the flow of heat and also it is concluded that the contribution to the heat transfer by the bare area is negligible. In the investigation it is deduced that the effective area may consist of: a) droplets with very small radii, and b) tiny portions of the liquid surfaces of large droplets. The tiny portion of the liquid surface can be visualized to lie in the vicinity of the droplet perimeter. The effective area is found to vary from one surface to another according to the substrate material. Concerning the influence of the presence of non‐condensable gases, the effective area is found to decrease rapidly with the increase of the air concentration.
Liquid‐liquid extraction in laminar slug flow
Authors: Baird M. H. I. , Ho M. K.
Published: March 2009

The hydrodynamics of liquid‐liquid slug flow have been studied for several organic components in water, in vertical tubes of diameters between 4.08 and 18.99 mm. Under conditions such that the slug flow is laminar and stable, mass transfer of sparingly soluble organic components (n‐butanol, n‐pentanol and methyl i‐butyl ketone) to water has been measured by observing the shrinkage rates of slugs. The observations are compared with predictions based upon the Higbie penetration model and the calculated velocity profile due to slug flow. It is concluded that the slug flow technique could be useful in studying the rates of reaction‐accompanied extraction.
Bulk and interfacial physical properties of aqueous solutions of sodium lauryl sulphate and lauryl alcohol. Part III: The effect of impurities and additives on pH and electrical conductance of premicellar and micellar solutions of sodium lauryl sulphate
Authors: Vijayan S. , Woods Donald R. , Lowe David
Published: March 2009

Experimental measurements of the pH, electrical conductance and Kraft temperatures were made for a number of commercially available and purified samples of sodium lauryl sulphate for a wide range of surfactant concentrations in aqueous solutiin at 25°C. The efect of lauryl alcohol and sodium chloride on the pH and electrical conductance was also studied. The effects of type of electrodes, sequence of measurements, the memory effect, mixing and carbon dioxide were explored for the pH measurements. The results show that pH is a convenient and reliable method for the determination of critical micelle concentration (CMC) of ionic surfactants.

The pH versus concentration data can also be used to uniquely identify the presence of contaminants or species other than pure sodium lauryl sulphate in that discontinuities occur in the data at unique concentrations so that identification of the contaminant is easy. High concentration discontinuities are identified and are attributed to individual or mixture CMC values. Anomalies in the data occur for concentrations less than 0.05 wt.% and especially around 0.01 to 0.02 wt.% for pure sodium lauryl sulphate solutions.

Data are also given that show the effects of aging. Data reported in the literature for the pH, electrical conductance and Kraft temperature are compared.