bluuebunny/crossref_metadata_2025_split huggingface dataset:
Breakthrough and Sulfate Conversion Analysis during Removal of Sulfur Dioxide by Calcium Oxide Sorbents
Authors: Dasgupta Kushal , Rai Kailash , Verma Nishith 
Published: July 2010

AbstractSorption of sulfur dioxide (SO2) was carried out on calcium‐based sorbents under dynamic conditions in a fixed bed. The experimental conditions were reaction temperature (700 to 1000°C), SO2 concentration (1000‐10 000 ppm), sorbent particles size (1 to 2 mm) and the types of sorbents (hydroxide or carbonate). The sorption process was found to be effective at low concentration levels (less than 10 000 ppm) as the breakthrough time significantly decreased with increase in concentration. The maximum removal of SO2 was observed at a reaction temperature of 950°C. The hydroxide‐based sorbents of relatively smaller particle size were found to exhibit superior sorption performance in terms of longer breakthrough time and higher sulfate conversion. A mathematical model developed, assuming a porous structure of the sorbent materials, attributed the low sulfation conversion during SO2 sorption due to a pore diffusion mechanism.
Effect of Frothers on Bubble Size and Foam Stability in Potash Ore Flotation Systems
Authors: Laskowski Janusz S. , Cho Yoon Seong , Ding Kejian 
Published: July 2010

AbstractThe objective of this project was to compare the effect of a selective flotation frother (MIBC) and powerful frothers (DEMPH and DF‐1012) on bubble size and foamability in water and in brine. In water, the bubble size is clearly reduced by flotation frothers which prevent bubbles from coalescing. The present study shows that the bubbles do not coalesce in brine and, therefore, frothers do not affect the size of bubbles in brine. The dynamic foamabality index measured in brine is much lower than that in water for weak frothers (e.g. MIBC); for both tested strong frothers the foamability measurements in brine reveal formation of meta‐stable foams.
Analysis of Steady‐State Temperature Profiles from a Laboratory Reactor by Means of a Process Simulator
Authors: Hudgins Robert R. , Posarac Dusko , Jaree Attasak 
Published: July 2010

AbstractA process simulator was used for the analysis of steady‐state results from a laboratory‐scale tubular reactor for the oxidation of carbon monoxide over a platinum catalyst. From a set of 14 steady‐state experiments, temperature profiles were simulated with two adjustable parameters recovered by optimizing the fit: k°, the pre‐exponential portion of the rate constant, and hout, the outer wall heat transfer coefficient for the reactor tube. Simulation showed that despite elaborate insulation the reactor did not behave adiabatically. Simulation also predicted fairly well the magnitude of phenomena such as ignition, extinction, and rate hysteresis (caused by changes in feed temperatures or concentrations) but at temperatures below the experimental values.
Dynamic Analysis of Thermal Behaviour of a Laboratory Reactor Using a Process Simulator
Authors: Hudgins Robert R. , Posarac Dusko , Jaree Attasak 
Published: July 2010

AbstractA process simulator was used to study dynamic results from a laboratory‐scale tubular reactor for the oxidation of carbon monoxide (CO) with oxygen over Pt/alumina catalyst. Passive response experiments were used to obtain lumped values of the heat capacity and the overall heat transfer coefficient. Temperature profile experiments were used to obtain the only adjustable kinetic parameter: k°, the pre‐exponential portion of the rate constant. Integral reactor phenomena were studied: step‐decreases in the feed temperature, step‐changes in feed concentration, and ignition of the reactor by pressure. Simulated results provided good agreement with experiments.
Residence Time Distribution of Solids in a Fluidized Bed
Authors: Babu M Prasad , Setty Y Pydi 
Published: July 2010

AbstractExperimental investigation on RTD of solids is carried out in a single‐stage fluidized bed provided with an internal, using uniformly sized particles and a binary solid mixture, varying gas flow rate, solids rate, bed height, dilution and the bed geometry. The effect of these variables on first and second moments as well as on F‐curves has been determined. Using a binary solid mixture or an internal inside the bed is found to reduce backmixing of solids. The data is fitted to FTEM and the values of N obtained were compared for different variables.
Fick's First Law of Diffusion and Binary Gas Separation by Hollow‐Fiber Asymmetric Membrane
Authors: Gornshteyn B. J. 
Published: July 2010

AbstractFor calculating mass transfer through a hollow‐fiber asymmetric membrane, a fundamentally new theoretical method based on Fick's first law of diffusion is proposed. The main features of this method, and the ones currently used for the same purpose, have been compared. The current methods, also based on Fick's first law of diffusion, are shown to be theoretically less than adequate. Recommendations are given for the practical implementation of the new method.
Modeling of Groundwater Contamination by Phenol Released from Spilled Bitumen
Authors: Tang Joseph S. 
Published: July 2010

AbstractLeaching of phenol from spilled bitumen into flowing aquifer poses an environmental threat to groundwater contamination. A two‐dimensional model with de‐coupled transfer was built to model phenol propagation in the flowing stream. The model predicted that the produced phenol concentration monitored at an observation well would rise sharply and then decline gradually as the phenol flux emerging from the bitumen surface was depleted with time. The model is useful in estimating the size of the spill, produced phenol concentration, phenol spatial distribution and the time required for the phenol concentration to decline to an environmentally acceptable level. It is well suited to other water pollution problems with chemical spills.
La génération de solides divisés par fluides supercritiques
Authors: Fages Jacques , Lochard Hubert , Rodier Elisabeth , Letourneau Jean‐Jacques , Sauceau Martial 
Published: July 2010

AbstractLes procédés de cristallisation utilisant les fluides supercritiques (FSC) constituent une nouvelle voie pour obtenir des solides finement divisés. En utilisant principalement la pression comme paramètre opératoire, ces procédés permettent l'obtention de poudres fines et monodisperses. On distingue deux familles de procédés selon que le fluide supercritique — généralement le CO2— est utilisé comme solvant (RESS) ou comme anti‐solvant (SAS). Pour le procédé RESS, la chute de densité liée à une détente brutale est le moteur de la nucléation. Pour les procédés de type SAS c'est la dissolution réciproque d'un solvant organique et du FSC qui provoque la précipitation. Des applications industrielles se dessinent dans de nombreux secteurs, même si c'est l'industrie pharmaceutique qui semble la mieux placée pour rassembler une majorité de ses développements.
Fluidized Bed Air Drying: Experimental Study and Model Development
Authors: Henneberg Markus , Heinrich Stefan , Ihlow Matthias , Mörl Lothar 
Published: July 2010

AbstractThe presented study describes the processes and mechanisms of batch fluidized bed drying. The influencing factors of hot air drying are theoretically and experimentally examined, in order to present the relations between temperature and humidity profiles and all other drying parameters. A physical model is presented to facilitate the calculation of the drying processes under defined conditions. Three succeeding drying stages are therefore modeled. Mass and energy balances including all components taking part in the process are formulated. The model clarities the drying process under the assumption of pure heat transfer mechanisms. It does not contain adaptive parameters and takes into account an inactive bypass fraction of the fluidization and drying medium. The evaluation of the model was successful for two fluidized bed plants with nominal widths of 100 mm and 400 mm. The experiments showed sufficient accuracy and transferability of the model to equipment of application‐oriented dimensions.
Modélisation de l'efficacité de filtration d'un échangeur cyclone
Authors: Caetano Richard , Donnot André , Rigo Marie‐Odile 
Published: July 2010

AbstractThis work is a modelling of the Aireco® filtration system. This heat exchanger, with particle catching capabilities, is made of a cyclonic body which contains refrigerated coils. The water vapour contained in the gas to be treated condensed on the coils surface. Our modelling considers two main capture surfaces: the entry zone in which particles are collected by inertial impaction and the cyclonic body in which particles diffused by centrifugal force is the main phenomena. We found that these considerations explain our experimental results with an accuracy more than 90%, when the Aireco® is on a normal point of working.
Selective Production of C4 Hydrocarbons from Syngas Using Fe‐Co/ZrO2 and SO42—/ZrO2 Catalysts
Authors: Bi Yonghong , Dalai Ajay K. 
Published: July 2010

AbstractModified Fischer‐Tropsch (MFT) syntheses were carried out to convert synthesis gas to C4 hydrocarbons over Fe‐Co/ZrO2 (FT) and SO42—/ZrO2 (SZ) catalysts in a dual reactor system, keeping the FT to SZ catalysts ratio at 1:1.5. Five Fe‐Co/ZrO2 catalysts with different Fe and Co loading, and SZ with 15 wt% SO42— were prepared and extensively characterized using various physico‐chemical methods. The FT synthesis process was initially performed using a Fe‐Co/ZrO2 catalyst in a single reactor and the effects of Fe and Co mass ratio, reaction temperature, space velocity on the production of C4 hydrocarbons and C2‐C4 olefins were investigated. Results indicated that a 3.71% Fe—8.76% Co/ZrO2 mixed oxide catalyst alone at 260°C and 5 h—1 gave high selectivities of C2‐C4 olefins (∼26.1 wt%) and total C4 hydrocarbon product (∼16.2 wt%). The MFT process 150°C gave higher C4 (∼31.6 wt%), isobutane (∼22.9 wt%) and C2‐C4 (31.1 wt%) selectivities.
Phase Diagram for Liquid Crystalline Polymer/ Polycarbonate Blends
Authors: Huang G , Chan P. K. , Kamal M. R. 
Published: July 2010

AbstractA novel mechanism to form binary polymer blends is through phase separation by spinodal decomposition in the unstable region of the phase diagram. The present work investigates the effects of thermally‐induced phase separation by spinodal decomposition on the morphology development of liquid crystalline polymer/polycarbonate blends. Moreover, a thermodynamic binary phase diagram is obtained using a twin‐screw extruder at various processing melt temperatures. Differential scanning calorimetry and scanning electron microscopy were used to study the miscibility of the blends and the resulting morphology. A thermodynamic binary phase diagram exhibiting a lower critical solution temperature was obtained. The droplet size distribution of the blend was also obtained and discussed in light of the Cahn‐Hilliard theory.
Scale‐up and Spouting of Two‐Dimensional Beds
Authors: Costa Márcio De A. , Taranto Osvaldir P. 
Published: July 2010

AbstractThe objective of this paper is to present an analysis on the scale‐up procedure of two‐dimensional spouted beds. The task was carried out with three different beds measuring 0.15, 0.30 and 0.80 in width. The conditions of scale‐up were studied through geometrical similitude analysis. Some parameters of scale were adimensionalised, tested and validated in order to propose relationships capable of predicting values of dependent properties. Those relationships should be followed in a prototype of an equipment of industrial scale. The study permitted the development of correlations to predict values of maximum pressure drop, minimum spout velocity and maximum height of spouting.
Dynamic Gauging in Duct Flows
Authors: Tuladhar Tri R. , Paterson William R. , Wilson D Ian 
Published: July 2010

AbstractDynamic gauging is demonstrated experimentally to work well in duct flows, thereby being suitable for monitoring the development of soft films in flowing systems, as illustrated using the growth of a freezing fouling layer viz. an ice film. For low duct velocities (440 < ReD < ca. 2000) we identify an undesirable multiple steady state phenomenon and show how to eliminate it. Dynamic gauging then proves useful up to ReD = ca. 10 000. Above that, we infer that the throat of the gauge nozzle would no longer be within the viscous sublayer and recommend further investigation of this regime.
Structural Disruption of Toothpastes Under Deformation — An Easy Release of Active Ingredients
Authors: Doytcheva Boyka K. 
Published: July 2010

AbstractThe author suggests a technological approach relevant to the optimization of toothpaste compositions with regard to the easy release of the therapeutic ingredients under shear deformation. It is based on the comparative assessment of the steady‐state viscous behaviour of placebo samples (mixtures containing all the components except the therapeutic ingredients) and the final products. It is presumed that the maximum beneficial effect of the toothpastes, as therapeutic agents, is achieved if the final products and the placebo blends display similar shear‐thinning characteristics.
Transfert de matière liquide‐disque dans l'écoulement radial divergent entre disques — étude portant sur différentes échelles du système
Authors: Fahidy Thomas Z. , Cœuret François 
Published: July 2010

AbstractLe travail étudie expérimentalement le transport de matière stationnaire liquide‐disque dans le cas de l'écoulement radial divergent entre disques circulaires parallèles faiblement distants. Les résultats sont analysés en prenant en compte l'influence de l'effet d'échelle, et au travers d'une corrélation empirique générale entre groupes adimensionnels (Sh, Re, Sc) et facteurs géométriques adimensionnels. La corrélation empirique obtenue est comparée à une solution théorique approchée pour le régime laminaire.
Airlift Bioreactors: Review of Recent Advances
Authors: Merchuk José C. 
Published: July 2010

AbstractAirlift reactors are popular in the modern bioprocess research and development, over a broad spectrum of processes. Those range from the production of very expensive biochemicals to wastewater treatment. In both extremes the reason behind the selection of the airlift reactor is related to fluid dynamic characteristics. During the last few years, a large number of research papers dealing with the dependence of reactor performance on liquid flow have been published. In some of them, descriptions of devices that have been developed in order to improve, or to gain further control of the fluid patterns in the reactor are reported.
Fluid Dynamic Studies in Support of an Industrial Three‐Phase Fluidized Bed Hydroprocessor
Authors: McKnight Craig A. , Hackman Larry P. , Grace John R. , Macchi Arturo , Kiel Darwin , Tyler Jonathan 
Published: July 2010

AbstractReducing gas hold‐up has been identified as a key objective to improve the performance of Syncrude's LC‐FinerSMunit. Redesign of the liquid recycle pan in the freeboard region, aided by multiphase CFD simulation and tests in a kerosene cold model experimental system, led to reduced gas hold‐ups. The addition of an anti‐foam agent did not provide any improvement. Cold‐flow dimensional similitude tests demonstrated the importance of gas density, distributor geometry, and interfacial phenomena. Grid redesign was undertaken to diminish swirl and provide improved radial distribution of gas. Dispersion tests indicate favourable catalyst mixing in the reactors.
Suspension of Particles from the Bottom of Pipes and Stirred Tanks by Gassed and Ungassed Flows
Authors: Thorpe Rex B. , Stevenson Paul 
Published: July 2010

AbstractWidely accepted correlations and theoretical predictions for hydraulic conveying of solids in pipelines are compared with the literature on the suspension of particles in stirred tanks. Good agreement is found between the correlations and the theoretical predictions both within and between the two fields of study. The effect on the suspension velocity of introducing gas into the pipe and the stirred tank is remarkably similar. In both cases, the shear stress remains broadly unchanged when gas is added. Since the effect of the addition of gas on shear stress is quite well understood in both cases, this is a helpful result.
Liquid Dispersion in Large Diameter Bubble Columns, with and without Internals
Authors: Forret Ann , Schweitzer Jean‐Marc , Gauthier Thierry , Krishna Rajamani , Schweich Daniel 
Published: July 2010

AbstractLiquid mixing has been studied in a 1 m diameter bubble column, with and without internals (vertical cooling tubes). The presence of internals significantly affects both large scale recirculation and local dispersion. The most common approach to model liquid mixing is the one‐dimensional axial dispersion model, validated many times in small bubble columns without internals. This paper shows that this model is still appropriate to large columns, but without internals. A two‐dimensional model, taking into account a radially dependent axial velocity profile, and both axial and radial dispersion, is required to account for the internals on liquid mixing.
Identification of Flow Regimes in a Flat Gas‐liquid Bubble Column via Wavelet Transform
Authors: Olmos Eric , Gentric Caroline , Midoux Noël 
Published: July 2010

AbstractA flat bubble column reactor is studied experimentally to increase the understanding of flow regimes and their transitions. To perform this, qualitative observations and global gas hold‐up measurements are used to detect flow regime transitions. Liquid velocities are measured with Laser Doppler Anemometry (LDA). However, as these signals contain a huge amount of information, it is necessary to use signal treatment techniques to analyse them. Wavelet transform was employed in the present paper. The results show that this technique is a powerful tool to (i) describe liquid flow macrostructures, (ii) study gas distributor effects and consequently, (iii) identify flow regimes.
Experimental Determination of Bubble Coalescence and Break‐up Rates in a Bubble Column Reactor
Authors: Laari Arto , Turunen Ilkka 
Published: July 2010

AbstractThe accuracy of CFD calculations of bubble column reactors is often limited by a lack of knowledge regarding bubble coalescence and break‐up rates. The models describing coalescence and break‐up rates have parameters, which cannot be estimated from the available physical properties. The main objective of this work was to test different coalescence and break‐up models and to develop experimental methods for estimating the model parameters. In the experiments bubble size distributions were measured photographically at several reactor heights. A population balance model describing the evolution of the bubble size distribution with respect to reactor height was developed and solved numerically.
Fluid Dynamic Behaviour of Two‐ and Three‐Phase Airlift Reactors
Authors: Di Felice Renzo , Eroles Carmen Monfort 
Published: July 2010

AbstractThis work deals with two‐ and three‐phase airlift systems, employing ambient air, tap water and plastic spheres. The dependency of the main parameters (gas and liquid hold‐ups, liquid circulation rate) on the only external factor, the gas flow rate was investigated. Liquid circulation rate was correlated by a pressure balance which lead to the experimental determination of an overall friction coefficient. A digital camera was used was used, in the second part of the investigation, to determine bubble hold‐up and bubble size distribution. Gas flow rate in the downcomer could be inferred and a tentative correlation with the flow condition prevailing in the riser was suggested.
Vertical Cylinder‐to‐Slurry Heat Transfer in a Gas‐Slurry Transport Bed
Authors: Muroyama Katsuhiko , Kato Takafumi , Masuda Takesi , Kinoshita Susumu 
Published: July 2010

AbstractIn the present study we measured the immersed vertical cylinder surface‐to‐slurry heat transfer coefficient in the liquid‐solid and gas‐slurry (three‐phase) transport beds at controlled solid concentrations. The slurry contained 0.1 mm inert glass beads and the solid fraction in the slurry was varied from 0% to 10% by volume. The liquid viscosity was widely varied by using water and a 1.0wt% aqueous CMC solution. A unified dimensionless equation for the heat transfer coefficient with a coefficient of variation of 14.9% was successfully formulated in terms of the Nusselt number, the Prandtl number and the specific power group including the energy dissipation rate per unit mass of slurry in both transport bed systems. The presence of a good analogy was ascertained between the heat transfer and mass transfer on the vertical cylinder.
Hydrodynamics of a Three‐phase Airlift Reactor with an Enlarged Separator — Application to High Cell Density Systems
Authors: Klein Jaroslav , Vicente António A. , Teixeira José A. 
Published: July 2010

AbstractThe hydrodynamic study of a three‐phase airlift reactor with an enlarged head zone was carried out. Effects of gas‐solid‐liquid separator design and riser to downcomer cross‐sectional area using different lengths and diameters of the draft tube were investigated. Ca‐alginate beads with entrapped yeast biomass at different loadings up to 21 % (v/v) were used in order to mimic the solid phase of conventional high cell density systems. The main hydrodynamic parameters — liquid circulation velocity, gas and solids holdups in all reactor sections have been measured and experimental values were satisfactorily predicted using an appropriate three‐phase model. The results of this study may be applied to suggest the optimal design (in terms of hydrodynamic behaviour) of a batch/continuous three‐phase ALR for high cell density fermentations.
Bubble Emission Frequency and Weeping Rate at a Submerged Orifice with Bulk Liquid Flow
Authors: Zhang Wenxing , Tan R. B. H. 
Published: July 2010

AbstractBubble emission frequency and weeping rate has been quantitatively compared in the case of induced and forced liquid flow. A stabilizing baffle was designed to eliminate induced liquid circulation and surface waves due to continuous gas emission. The effects of presence or absence of stabilizing baffle on bubble frequency and weeping rate were shown. Forced liquid cross‐flow was produced and the effect on reducing weeping rate was presented. The results show that liquid weeping is significantly reduced in unbaffled, swirling flow and also with liquid cross‐flow. This is due to a combination of an increase in bubble frequency and a decrease in driving force for liquid weeping. The practical implications of our findings are discussed.
Bubble Distribution in Shear Flow of Highly Viscous Liquids
Authors: Terasaka Koichi , Murata Sayako , Tsutsumino Kaori 
Published: July 2010

AbstractThe size of bubbles distributed from a horizontal nozzle into shear field generated by a Couette flow between concentric cylinders was investigated using dual high‐speed video cameras as parameters, i.e., shear rate, gas flow rate, nozzle diameter, gas chamber volume and liquid viscosity. When the bubble was lifted up by buoyancy and stretched horizontally by shear flow, the cut of the bubble neck was caused by the greater deformation. When the inclined bubble angle by shear flow was greater than the elevation angle by buoyancy, the bubble's detachment was governed not by viscosity but by shear flow. To estimate the bubble size, a correlation equation was proposed in this study.