bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gasification kinetics of oil sands coke
Authors: Nguyen Q. T. , Watkinson A. P. 
Published: March 2009

AbstractKinetics of steam gasification of delayed and fluid cokes derived from Athabasca bitumen have been studied in 6.35 cm diameter stirred and fixed bed reactors. Experiments were carried out at atmospheric pressure and at temperatures between 800°C and 930°C. The coke particle size ranged from 0.1 to 3.5 mm, and the steam partial pressure was varied from 15.2 to 60.6 kPa. Scanning electron microscopy, surface area analysis, and mercury porosimetry were employed to relate physical structure changes in the solids to experimental kinetic data. Several kinetic models for gasification were tested with the experimental gasification data. Rate expressions are presented for carbon conversion and for the release of sulphur.
Dynamic behavior of mixer‐settlers
Authors: Salem Abu Bakr , Sheirah Mohamad A. 
Published: March 2009

AbstractA mathematical model has been developed to simulate and predict the dynamic behavior of liquid extraction counter current operations in mixer‐settler units. Murphree efficiency has been included in the model. The behavior of a multistage glass mixer‐settler has been studied under start‐up transient conditions. Very good agreement between the simulation results and the experimental findings have been obtained. The simulation results showed that this model can efficiently be used to determine the optimum number of stages, the capacity of each stage, the phase ratio and the time required for each unit to attain steady state conditions. Other controlling parameters in operating such units are investigated.
The mixing cells model applied to a fixed bed dryer
Authors: Costa Vitor A. F. , Figueiredo A. Rui A. 
Published: March 2009

AbstractThe system of Partial Differential Equations for the simultaneous heat and mass transfer in drying of a fixed bed is highly non‐linear, and the numerical resolution requires much computing time when a conventional finite‐difference scheme is employed. An Ordinary Differential Equations system with the same physical significance and of a stiff nature is obtained by the mixing cells model. The criterion for prescribing the number of cells is outlined and the computed temperature distributions are compared with those available from the literature. The method also enables simulation of the condensation of drying air over the product but, under such conditions, the computing time is greatly increased.
Solving dynamic equations for the collection and evaporation of an aerosol
Authors: Viljoen H. J. , Eyre D. , Wright C. J. 
Published: March 2009

AbstractWe investigate the coalescence of drops undergoing random Brownian motion and evaporation. The evolution of the drop size spectrum is determined by solving a partial integro‐differential equation with a kernel that describes the pairwise coalescence of drops. Numerical results for fuel injection with n‐octane suggest that the size distribution of drops is determined by two competing processes, namely coalescence and evaporation.
Forced oscillations of concentration in transport reactors
Authors: Prashant C. , Chidambaram M. 
Published: March 2009

AbstractThe performance of a transport catalytic reactor is analysed for an adsorption/desorption type model with Eley‐Rideal surface kinetics with square wave oscillations in the feed concentration. The inlet average concentration of both the reactants over a period is assumed to be constant. Significant improvement in the yield of product is obtained by increasing the feed concentration of both the reactants in the first fraction of a period. The effect of adsorption capacity of the catalyst, reaction rate constants, and inlet feed mean concentration of the reactants are evaluated. The deactivation of active sites, due to product inhibition, introduces resonance in the yield versus cycle split. The yield of product shows a minimum with respect to cycle split for the type of forcing where one of the reactant concentrations increases and the second reactant concentration decreases in the first fraction of a period.
Traitement et valorisation des eaux usées agro‐alimentaires: Faisabilité du procédé aérobie thermophile pour un effluent d'abattoir
Authors: Couillard D. , Gariépy S. 
Published: March 2009

AbstractLa présente étude s'inscrit à I'inékrieur de travaux de développement d'un procédé de traitement des eaux usées permettant aussi la récuperation des éléments nutritifs contenus dans les effluents de I'industrie agro‐alimentaire. Un effluent d'abattoir a été soumis à une série d'essais à I'échelle du laboratoire a des températures de 45, 52 et 58°C. L'efficacité du procédé sur le plan traitement a été démontrée par l'enlèvement de plus de 90% de la demande chimique en oxyéne (DCO)pour tous les temps de séjour étudiés (6, 12, 18, 24 et 30 heures)à 21 45 et 52°C. Le contenu en protéines brutes de la biomasse recueillie atteignait en moyenne prés de 70% sur une base sèhe, et la composition en acidés aminks de la protéine s'est révélee adéquate pour introduction à titre de concentré dans les rations alimentaires du porc et de la volaille.
The development of a deep knowledge diagnostic expert system using fault tree analysis information
Authors: Adamson M. S. , Roberge P. R. 
Published: March 2009

AbstractIn this paper a diagnostic Knowledge Based Expert System (KBES) prototype for a nuclear Auxiliary Boiler Feed System (ABFS) was developed. A commercial Expert System shell accesses heuristic production rules to quickly resolve the majority of common faults. Supplementing this are a series of C functions which access the Fault Tree data base previously developed during the licensing process. These functions perform diagnostics, give detailed explanations of failure mechanisms, and identify system failure risks through examination of cut sets. The capture of both heuristic and Fault Tree information has resulted in a more exhaustive diagnostic tool with a domain of application unrestricted by the limitations of previous operator experience.
Multi‐input adaptive‐predictive control of kamyr digester chip level
Authors: Allison B. J. , Dumont G. A. , Novak L. H. 
Published: March 2009

AbstractThis paper investigates the development and industrial application of a multi‐input/single‐output adaptive‐predictive Kamyr digester chip level controller based on Generalized Predictive Control (GPC). The controller simultaneously manipulates the blow flow and the chip meter to control the chip level. The chip meter is manipulated in a way which tends to maintain the desired production rate, while still leaving some room for control. The idea was to use the chip meter as a second input variable to reduce blow flow manipulation and, thereby, reduce disruptions to the chip column movement. The two‐input strategy decreased blow flow manipulation by more than 50% (compared to an otherwise equivalent one‐input scheme) without sacrificing output performance. However, the anticipated improvements in permanganate‐number variability were not achieved. The multi‐input strategy was discontinued after six months of operation.
Effect of the choice of final time in optimal control of nonlinear systems
Authors: Luus Rein 
Published: March 2009

AbstractThe choice of the final time, tj, in the optimal control of nonlinear systems is shown to be very important. By choosing tf to be small, and repeatedly optimizing the system operation over the short time intervals gives a highly oscillatory type of control for a particular nonlinear chemical reactor. The cumulative profit as compared to that obtained by choosing tf to be large, is substantially lower. In the operation of a batch reactor it is shown that if tf is small, bang‐bang control with singular sub‐arcs results. When tf is large, the optimal control policy tends to be relatively smooth and the profitability is substantially improved.
The effect of dehydration conditions on the adsorption and diffusion of propane and nitrogen in linde 5A zeolite
Authors: Tezel H. O. , Ruthven D. M. 
Published: March 2009

AbstractDiffusion of propane and nitrogen in small crystals (3.6 μm) of zeolite 5A has been studied by conventional uptake rate measurements. The zeolite crystals were subjected to various pre‐treatments prior to propane and nitrogen adsorption. It is concluded that surface degradation due to pre‐treatment is not believed to occur to a significant extent since it has been observed that after a proper regeneration of the adsorbent, the diffusional properties of the system have been restored. It is suggested that the Ca++ cations which may initially obstruct the windows of the sieve become increasingly mobile with increasing sorbate concentration and move to sites within the cage. The results are broadly consistent with the study on the diffusional transition in zeolite NaX (Tezel et al., 1983).
The effect of specific growth rate and death rate on monoclonal antibody production in hybridoma chemostat cultures
Authors: Linardos Theodor I. , Kalogerakis Nicolas , Behie Leo A. , Lamontagne Louis R. 
Published: March 2009

AbstractExperimental data collected from bench‐scale chemostat cultures of mouse‐mouse hybridoma cells have been used for the development of a kinetic model of monoclonal antibody production. The specific antibody productivity was found to be proportional to the specific death rate, indicating a stimulating effect of stress on the ability of the cells to produce antibody. The death rate was found to be an exponential function of the average cell age in the culture. Furthermore, a Generalized Maintenance Energy (GME) model is proposed, to take account of the effects of culture stress on the nutrient uptake rates. The proposed relationships agreed very well with other mouse‐mouse hybridoma chemostat culture data in the literature.
Approximate analytical solutions for a biofilm reactor model with Monod kinetics and product inhibition
Authors: Bhaskar G. V. , Bhamidimarri S. M. Rao 
Published: March 2009

AbstractThis paper presents a method for obtaining approximate analytical solutions based on a Taylor series linearization technique for a biofilm reactor with Monod kinetics and product inhibition. Of the two inhibition types investigated, the linear inhibition solution was in explicit form, while the exponential inhibition solution was in series form. The results of the approximate solution agree well with the numerically exact solution.
Enzyme mass transfer coefficient in aqueous two phase system using a packed extraction column
Authors: Patil T. A. , Jafarabad K. Rostami , Sawant S. B. , Joshi J. B. 
Published: March 2009

AbstractFractional dispersed phase hold‐up and dispersed side mass transfer coefficients for amyloglucosidase were measured in a 56 mm i.d. packed extraction column using a sodium sulphate‐polyethylene glycol 4000 system. Raschig rings (3 to 13.3 mm), Berl saddles (12 mm), Pall rings (12.6 mm), glass spheres (5.2 mm) and structured wire gauze were used as packings. The effect of packing size was investigated in the case of ceramic Raschig rings. The effect of phase composition of the aqueous phase system also was studied.Correlations have been developed for fractional dispersed phase hold‐up and volumetric mass transfer coefficient with packing voidage, dry surface area of packings, superficial dispersed phase velocity and the liquid phase physical properties.
Kinetic model of parallel self‐poisoning in the catalytic hydrogenolysis of ethane on single‐type surface sites
Authors: Szamosi Janos , Kristyan Sandor 
Published: March 2009

AbstractA kinetic model for parallel competitive self‐poisoning in the catalytic hydrogenolysis of ethane has been developed. It is assumed that molecular hydrogen is the bond‐splitting agent in the rate‐determining step, and self‐poisoning itself is reversible. In addition, all active surface sites are taken to be of the same kind. The model provides a satisfactory account of the experimentally observed kinetic behavior.
Procéadéa de solubilisation biologique des méataux dans les boues anaéarobies d'éapuration: Filtrabilitéa, neutralisation et teneurs en n et p des boues traitéaes
Authors: Couillard D. , Mercier G. 
Published: March 2009

AbstractLa solubilisation biologique des métaux lourds contenus dans des boues anaérobies d'épuration a été effectuée dans un réacteur en continu á deux temps de séjour (0.5, 0.75 jour). Suite á la filtration des boues traitées, les pourcentages du Cu et du Zn solubilisés sont passés de 92% et 94% á 78% et 77% dans la boue filtrée. Le fer reprécipite en grande partie dans les boues filtrées. Les boues traitées sont faciles á déshydrater. l'indice de filtrabilité (r0.5) des boues traitées est 38 fois inférieur a celui des boues anaérobies, sans ajout de polymère. Les r0.5 obtenus, inférieurs á 8 × 1012 m/kg, permettent la déshydratation des boues sans ajout de polymère par un filtre‐presse á plateaux. La centrifugation est aussi envisageable. l'azote total, le phosphore total ainsi que le phosphore hydrolysable restent inchangés tout au long du traitement. l'ammoniac est perdu á 47% dans le filtrat. La neutralisation des boues traitées (pH = 7) et du surnageant contaminé (pH = 10) requiert une faible quantité de base. La précipitation sélective de métaux devrait permettre une recuperation du Cu contenu dans les boues métalliques générées. Enfin, les résultats obtenus indiquent la préfaisabilité du procédé et une étude á l'echelle pilote devrait permettre la mise á l'échelle réelle du procédé.
Improving prediction of salt effect on vle of isopropyl alcohol‐h2o‐salt and methanol‐h2o‐salt systems with preferential association
Authors: Lee Liang‐Sun , Tsao Yung‐Zin , Yang Barry L. M. 
Published: March 2009

AbstractWhen a salt is added to an azeotropic mixture, the azeotropic composition tends to shift or even disappear, due to salt‐in and salt‐out effects. Models from the literature are applied to calculate the vapor‐liquid equilibrium of systems of isopropyl alcohol H2O‐salt, and methanol H2O‐salt. Schmitt and Vogelpohl's model (1982) gives the best results. With the concept of preferential association, an improvement can be accomplished through the modified distribution factor of the salt associating with components of the mixture for the systems mentioned above.Owing to the lack of solubility data of the salt in the individual components of the azeotropic mixture, the generality of this modification has not yet been demonstrated.
Étude d'un procédé de pyrolyse rapide du charbon dans un réacteur cyclone
Authors: Houzelot J. L. , Hilaire P. , Lebrun‐Cabon A. , Villermaux J. , Bertav R. , Isler D. 
Published: March 2009

AbstractExperimental results on fast pyrolysis of coal in a steady state pilot reactor at a flowrate of 0.1 kg/h are examined in this article. The pyrolysis reactor is a cyclone. Using such a system it was possible to achieve simultaneously the reaction and the separation of semi‐cokes from volatiles produced by pyrolysis. A pump enabled gas recycling on the experimental setup and allowed a good hydrodynamic regime in the reactor. Only gases were recycled, liquids and tars being condensed and recovered.Experiments were carried out on a Lorraine coal (Houve well). From 100 grams of coal, 60 grams of semi‐coke, 35 grams of liquids, and 5 grams of gas containing 66% hydrogen and 30% methane were obtained. For the interpretation of results, an experimental kinetics study on coal grain pyrolysis is presented for grains in the range of 2.5 to 20 mm and temperatures between 700 C and 1050 C.
Accelerated successive substitution schemes for bubble‐point and dew‐point calculations
Authors: Peng Ding‐Yu 
Published: March 2009

AbstractThe accelerated successive substitution (SS) algorithms developed by Mehra et al. for flash calculations have been extended to the prediction of saturation points. A transformation matrix which is used to calculate the acceleration parameter has been rewritten in a form that is applicable at the saturation conditions. Simple equations for estimating the initial values and recursive formulae according to which the iterates can be updated are presented. The proposed schemes were compared with the conventional SS method and a multivariate Newton's method. The comparison suggests that the accelerated SS schemes are more tolerant of poor initial values and sometimes more efficient than Newton's method.
Elucidation of mean voidage in packed beds
Authors: Foumeny E. A. , Moallemi H. A. , Mcgreavy C. , Castro J. A. A. 
Published: March 2009

AbstractMean voidage is a global structural property of packed beds and its accurate prediction is therefore of great significance in any plug‐flow type model. A general correlation has been developed which enables this parameter to be evaluated. The work reported here deals with mono‐size non‐porous spherical packing, but also tackles related issues such as size distribution and the way in which they influence the mean voidage. In addition, an attempt has been made to discuss the merits of alternative packing arrangements.
Phase equilibrium in the system water‐hydrogen sulphide: Hydrate‐forming conditions
Authors: Carroll John J. , Mather Alan E. 
Published: March 2009

AbstractRecently revealed problems with the fluid phase equilibria data for the system H2S‐H2O as presented by Selleck et al. (1952) prompted this review of the hydrate‐forming conditions. The smoothed tables of Selleck et al. (1952) along the three‐phase loci are replaced with equations which are based on a critical review of all of the experimental data.
Deposition velocity correlation for water slurries
Authors: Gillies R. G. , Shook C. A. 
Published: March 2009

Abstracta Correlation to predict the deposition velocity of aqueous slurries is presented. The correlation employs the viscosity and density of the mixture of fluid and (‐74 μm) particles, as well as the mass median diameter (d50) of the fraction coarser than 74 μm. The correlation is derived from isothermal flow experiments using pipelines of diameter between 0.053 and 0.495 m.
Drying in capillary‐porous cylindrical media
Authors: Robbins M. C. , Özişlik M. N. 
Published: March 2009

AbstractAnalytical solutions are presented for temperature and moisture distributions in a cylindrical capillary‐porous body using Luikov's model and employing a solution technique based on the decoupling of the simultaneous heat and mass diffusion problems. The relative importance of the dimensionless parameters governing drying is presented and a comparison of temperature and moisture profiles for the cylinder and the slab is given.
Marangoni and buoyant convection in a cylindrical cell under normal gravity
Authors: Szymczyk J. A. 
Published: March 2009

AbstractThe present paper deals with the investigation of thermocapillary and natural convection by applying a white light‐sheet technique for the simultaneous determination of the velocity and the temperature field. The oscillatory Marangoni convection has been visualized with differential interferometry. Streamlines, velocity profiles and isotherms are presented and discussed. A complete separation of a surface tension driven convection roll of hot fluid in the boundary layer and a buoyancy driven convection roll of colder fluid in the liquid volume was discovered. For large driving forces (large Marangoni number) inertia becomes effective and the interface becomes the source of localized eruptions.
Solvent extraction — the challenges of a “mature” technology
Authors: Baird M. H. I. 
Published: March 2009

AbstractThe solvent extraction area is perceived by some chemical engineers as being mature and fully developed. The present review shows that this is not the case. Many chemical engineering problems must be solved before equipment can be confidently designed from first principles. The review also outlines progress in extraction process chemistry, and in new techniques such as membrane extraction.
An improved correlation for turbulent drag reduction in dilute polymersolutions
Authors: Darby Ron , Pivsa‐Art Suchat 
Published: March 2009

AbstractThe model for turbulent drag reduction in dilute polymer solutions developed by Darby and Chang (1984), and modified by Darby et al. (1989) has been further refined to significantly improve its ability to represent data for a variety of polymer solutions over a wide range of conditions. It is also shown how the rheological parameters in the model can be obtained from two or three data points for turbulent flow, in lieu of laminar viscometric measurements. This technique is applied to a wide variety of turbulent drag reduction data taken from the literature to demonstrate the general applicability of the model. The model is also shown to be consistent with Virk's maximum drag reduction asymptote (Virk, 1975) in the high Reynolds number limit.
Effects of stagnant and dispersion conductivities on non‐darcian forced convection in square Packed‐Sphere channels
Authors: Chou F. C. , Chung P. Y. , Cheng C. J. 
Published: March 2009

AbstractThis paper presents a numerical and experimental investigation of the effects of stagnant and dispersion conductivities on non‐Darcian forced convection in square packed‐sphere channels. The theoretical prediction of Nusselt number are found to be in good agreement with the experimental data. A larger near‐wall damping of stagnant conductivity is found for the present water‐steel medium than for that described by the mixing rule based on the volume fraction. A nonlinear Peclet number dependence, Peλ and λ = 0,88, for dispersion conductivity is found to induce better agreement between the theoretical and experimental results especially for the cases of high Peclet number and high Dc/d.
A study of the dynamics of anodic copper dissolution in a NaCl/KSCN electrolyte
Authors: Gu Z. H. , Fahidy T. Z. 
Published: March 2009

AbstractThe oscillatory behaviour of the anodic dissolution of copper into an aqueous NaCl solution containing a small amount of thiocyanate ions has been studied experimentally in the absence and in the presence of a magnetic field. The latter has an inhibiting effect on the oscillation and, under specific conditions, it can fully suppress it.
Absorption kinetics of ozone in aqueous O‐cresol solutions
Authors: Beltran F. J. , Encinar J. M. , Garcia‐Araya J. F. 
Published: March 2009

AbstractThe kinetics of ortho‐cresol ozonation in water has been studied using the film theory. At most experimental conditions investigated, the kinetic regime of the absorption has been fast pseudo first order with respect to ozone. At 30°C mass transfer plays an important role in controlling the absorption rate of ozone. The selfdecomposition reaction of ozone does not take place because of the great reactivity of o‐cresol with ozone. Reaction rate constants have been determined at pH 7 for different temperatures below 30°C. The following Arrhenius equation was obtained:kT = 2.2 × 1023 exp(‐11784/T), L/mol ṁ sAt temperatures below 30°C there exists an ozone partial pressure value above which the ozone absorption kinetic regime changes to fast second order regardless of experimental conditions.
Surface tensions and contact angles due to lignin sulphonates in the system: Liquid sulphur, aqueous zinc sulphate and zinc sulphide
Authors: Owusu George , Peters Ernest , Dreisinger David B. 
Published: March 2009

AbstractSurface tension and contact angle measurements were made in the liquid sulphur‐aqueous zinc sulphate‐zinc sulphide system at superatmospheric pressures, and showed that, in the absence of surfactants, the liquid sulphur‐aqueous solution interfacial tension was 54.0 ± 1.0 mN/m, falling to 27.0‐30.0 mN/m when 0.3 g/L or more of lignin sulphonate was added to the solution. At the same time, the contact angle between liquid sulphur and the same solution increased from 80 ± 5° to 148 ± 5°. As a result, the work of adhesion between liquid sulphur and zinc sulphide falls from 63.7 mJ/m2 to about 5.3 mJ/m2. The results indicate that adsorption of lignin sulphonate occurs on both the mineral‐aqueous and the sulphur‐aqueous interfaces.