bluuebunny/crossref_metadata_2025_split huggingface dataset:
Flooding and axial dispersion in reciprocating plate extraction columns
Authors: Hafez M. M. , Baird M. H. I. , Nirdosh I. 
Published: March 2009

AbstractThe 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

AbstractThe 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

AbstractThe 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

AbstractThe 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

AbstractThe 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

AbstractThe 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

AbstractCapital 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

AbstractMeasurement 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

AbstractA 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

AbstractDropwise 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

AbstractA 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

AbstractThe 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

AbstractExperimental 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.
Effect of convective velocity on longitudinal diffusivities in a fluidized cascade separator
Authors: Muzyka D. , Beeckmans J. M. 
Published: March 2009

AbstractExperimental results are presented on the separation of trace quantities of charcoal particles from salt crystals in a counter‐current fluidized cascade, for a range of paddle velocities extending over two decades. Interpretation of these data suggests that longitudinal diffusivity D is a function of horizontal convective velocity vH. The dependence of D on vH is attributed to mechanisms similar to those occurring when a pulse of soluble dye is suddenly injected into a solvent flowing in a pipe or a capillary, a situation first analyzed by Taylor(1,2).Experimental measurements were also made on the dispersion of a thin vertical layer of tracer material, following fluidized channel flow, using the same materials and conditions as were used in the fluidized cascade experiments. These data confirmed the general form of the dependence of D on vH found with the cascade, but yielded much lower values. The reasons for the discrepancy are not known, and further work is required to clear up this discrepancy.
Reliability and limitations of pulse chromatography in evaluating properties of flow systems: 1. modelling and experimental considerations
Authors: Gangwal S. K. , Hudgins R. R. , Silveston P. L. 
Published: March 2009

AbstractReproducibility of response characteristics and parameters derived therefrom, and adequacy of the Kubin‐Kucera model for pulse chromatography were investigated experimentally using the physisorption of methane and ethane on silica gel. Reproducibility was found to be excellent, while the agreement of predicted and observed effects of velocity, particle size, temperature and bed length on model parameters confirmed the adequacy of the model. Agreement of the pore diffusivity and the adsorption equilibrium constant with values measured by other techniques provide further support for the model. Rearrangement of model terms shows that the rate coefficient for physisorption and the mass transfer coefficient cannot be measured using chromatography.
Quasi‐Newton methods for convergence acceleration of cyclic systems
Authors: Soliman M. A. 
Published: March 2009

AbstractThis paper describes a version of Quasi‐Newton methods for solving a set of non‐linear algebraic equations. This method is simple, efficient, and requires little computer storage. This makes it suitable for the calculations of recycle streams in the simulation of chemical processes. Two examples are worked out to illustrate the good convergence of the present method as compared to commonly used methods.
Effect of drag‐reducing additives on free oscillatory flow
Authors: Mccomb W. D. , Ayyash S. 
Published: March 2009

AbstractThe damping rates of free oscillations in U‐tube manometers were measured in water and aqueous solutions of Polyox WSR 301, Separan AP273 and a wetting agent (Aerosol OT). The manometers were made from flexible plastic (PVC) or glass tube. Small reductions of the linear damping constant by low concentrations of Polyox and Aerosol additives in the PVC tubes were attributed to a reduction in surface tension effects. All the additives increased the linear damping constants in both types of manometer, when used at larger concentrations. This was found to be due solely to increased solution viscosity.Large fractional reductions in damping due to Polyox in the PVC‐tube systemwere associated with the nonlinear oscillations in the final period of the decay. This effect has not yet been explained.
Economics of fermentation processes for SCP production from agricultural wastes
Authors: Mooyoung M. , Moreira A. R. , Daugulis A. J. 
Published: March 2009

AbstractTwelve scenarios are considered as potential energy‐conserving processes for the simultaneous production of feed SCP and fuel gas from agricultural wastes. These scenarios are alternative schemes within three basic processing strategies that include either free‐standing anaerobic digestion systems or integrated anaerobic/aerobic fermentation systems. Material and energy balances were performed and used for preliminary process economic evaluations for farm‐based operations.The free‐standing anaerobic fermentation systems, and some of the systems based on semi‐solid or liquid aerobic fermentations appear to be the most attractive ones with the present technical know‐how. Raw materials and energy are the major components of the final product cost, which can be dramatically reduced by technological breakthroughs now being developed. Sensitivity analyses reveal that scale of operation has a significant effect on the protein production cost. Projections made for a period of 5 and 10 years from the present indicate that the economic viability of the scenarios is better in future markets where protein costs are expected to increase rapidly.
Reliability and limitations of pulse chromatography in evaluating properties of flow systems II. end effects
Authors: Gangwal S. K. , Hudgins R. R. , Silveston P. L. 
Published: March 2009

AbstractDead volume cannot be avoided in measurements of kinetic and transport parameters using pulse gas chromatography. A criterion is derived for the bed volume necessary to make these dead volume effects negligible. Application of the criterion and assumptions made in its development are discussed.
Le rendement de deux réservoirs agités en série avec alimentation séparée, basé sur la cinétique de monod
Authors: Lo S. N. , Marchildon L. , Valade J. L. 
Published: March 2009

AbstractThe performance of a bioreactor composed of two chemostats in series can be affected significantly by the split of feed into two, one for each chemostat, for reactions following Monod kinetics. Under certain operating conditions, split of feed can be greatly beneficial to the reactor performance.Optimization of performance is discussed; a general criterion is presented, applicable to either the maximization of overall conversion for a given total residence time or the minimization of total residence time for a given overall conversion. The maximization of overall conversion has also been studied with respect to the feed‐split ratio. The dimensionless Michaelis‐Menten constant is a very important parameter in the selection of optimal operating conditions.
Continuous emulsion polymerization of vinyl acetate. Part I: Experimental studies
Authors: Kiparissides C. , Macgregor J. F. , Hamielec A. E. 
Published: March 2009

AbstractAn interesting feature of commercial continuous emulsion polymerization reactors is the important phenomenon of sustained oscillations. Laboratory investigations of emulsion polymerization in a continuous stirred tank reactor (CSTR) have shown that the conversion, number of polymer particles and other related properties often oscillate widely with time. These oscillations can lead to emulsifier levels too small to adequately cover polymer particles resulting in excessive agglomeration and reactor fouling. Herein is reported an extensive experimental study of vinyl acetate emulsion polymerization in a CSTR. The effects of initiator and emulsifier concentrations, mean residence time and rate of agitation on the production rate and size distribution of polyvinyl acetate latices were investigated. Domains of reactor operation which give rise to sustained oscillations and massive agglomeration of the latex are mapped which give rise to sustained oscillations and massive agglomeration of the latex are mapped out. The effect of different start‐up policies on reactor transients were also investigated.
Continuous emulsion polymerization of vinyl acetate. Part III: Detection of reactor performance by turbidity‐spectra and liquid exclusion chromatography
Authors: Kiparissides C. , Macgregor J. F. , Singh S. , Hamielec A. E. 
Published: March 2009

AbstractHerein is reported an experimental evaluation of turbidity‐spectra and of liquid exclusion chromatography (LEC) for the online and offline monitoring of polymer particle size during the continuous emulsion polymerization of vinyl acetate. It is shown that these analytical techniques satisfactorily follow the change of particle size for reactor operation under conditions of sustained oscillations.
Energetic aspects of turbulence promotion applied to electrolysis processes
Authors: Storck A. , Hutin D. 
Published: March 2009

AbstractThis paper presents a simple and rational method for determining how much hydrodynamic factors influence the rate of production in electrochemical systems using turbulence promoters in various alternative flow conditions.Empirical and theoretical data correlations of limiting current densities (or mass transfer coefficients) and pressure drops are presented in unobstructed channels as well as for eddying flow induced by different types of eddy promoters.Based on the dimensional analysis and on the experimental results, it is shown that, within a given range of variations, all the promoters have an equivalent energetic effectiveness.However, when the conversion factor of the reacting species through the electrochemical reactor is near unity (complete transformation), this conclusion is no longer valid and the general methodology presented in this work shows that the rates of production present large differences depending on the system considered, the less sophisticated system (unobstructed channel) being the most effective.
Wave profiles on inclined falling film
Authors: Esmail M. N. 
Published: March 2009

AbstractThe profiles of waves travelling over the free surface of a liquid film, falling along an inclined flat wall, have been calculated, using a non‐linear technique of dynamic analysis. The wave profiles range from a simple nearly sinusoidal shape with small amplitudes, to a complicated profile close to solitary waves with high amplitudes. The results agree with earlier experimental observations, and are consistent with the results of the hydrodynamical theory of stability. Some of the solution trends have been observed to a lesser extent in previous non‐linear theories. It is clear that the phenomena associated with wave formation on a falling film, observed under the experimental conditions, arise because the problem is essentially non‐linear.
Interfacial tension from height and diameter of a single sessile drop or captive bubble
Authors: Malcolm J. D. , Elliott C. D. 
Published: March 2009

AbstractThe silhouette of a sessile drop submerged in a transparent bulk phase appears to possess a contact angle of 180° with a plane solid support, when the drop is separated from the solid surface by a thin film of surrounding fluid. A computer‐aided analysis of the generalized sessile drop form leads to an explicit equation for interfacial tension dependent only on drop height (from apex to solid support) and the magnitude of the drop equatorial diameter. The equation is valid for a wide range of physically realizable drops. Measurements of drop profile coordinates or the location of the drop equator are not required for the use of the method, leading to improvements in accuracy relative to current practice.