bluuebunny/crossref_metadata_2025_split huggingface dataset:
Equilibrium solubility of H2S and CO2 and their mixtures in a mixed solvent
Authors: Macgregor Rosalynn J. , Mather Alan E. 
Published: March 2009

AbstractThe solubility of hydrogen sulphide, carbon dioxide, and their mixtures has been measured at 40° and 100°C in a mixed solvent consisting of 20.9 wt% MDEA (methyldiethanolamine), 30.5 wt% sulfolane (tetrahydrothiophene‐1, 1‐dioxide), and 48.6 wt% water. The results have been compared with those for aqueous 2.0 mol/dm3 MDEA and an analogous mixed solvent, containing AMP (2‐amino‐2‐methyl‐1‐propanol), which are available in the literature. These data were used to modify the solubility model of Deshmukh and Mather (1981) to account for the mixed solvent effects on the system thermodynamics. Results show that the model is useful as a first approximation in predicting acid gas solubilities; agreement with experiment was generally found to be within £15%.
Binary liquid–liquid equilibria of aniline–paraffin and furfural–paraffin systems
Authors: Sen Subhash C. , Maity Soumen , Ganguli Kausik , Goswami Kausik , Ray P. 
Published: March 2009

AbstractBinary liquid‐liquid‐equilibria data for several aniline‐paraffin and furfural‐paraffin systems have been taken. These data along with data for other aniline‐hydrocarbon and furfural‐hydrocarbon systems from literature have been correlated using UNIFAC model. The UNIFAC group interaction parameters have been found to have a linear temperature dependence. The CH2 groups in cyclo and non cyclo paraffins require different interaction parameters. It was also found that a scaling of the combinatorial term is necessary for higher molecular weight hydrocarbons.
Void‐size distribution in two‐dimensional random packings of equal‐sized disks
Authors: Alonso M. , Satoh M. , Miyanami K. 
Published: March 2009

AbstractThe void‐size distribution in a random packed assembly of disks is expressed here as the distribution of the probabilities of finding circular voids of given sizes. A theoretical void‐size distribution is derived and compared with the distribution obtained through computer simulation. The two‐dimensional case discussed in this paper is applicable to the study of the kinetics of fines transfer and the characterization of the coating layer structure in powder coating systems.
Correlations for liquid‐phase mass transfer coefficients in bubble column reactors with newtonian and non‐newtonian fluids
Authors: Kawase Y. , Moo‐Young M. 
Published: March 2009

AbstractThe earlier work of Calderbank and Moo‐Young (1961) dealing with the liquid‐phase mass transfer coefficient in gas‐liquid dispersions is examined. Their well‐known empirical correlations for small and large bubbles which are free to move under gravity are theoretically derived. The analyses are based on the approach for natural convection mass transfer, and include the case where the fluid is non‐Newtonian. The predictions of the models are compared with reported experimental data and correlations.
Heat and mass transfer between bubbles and a liquid
Authors: Guy C. , Carreau P. J. , Paris J. 
Published: March 2009

AbstractThe understanding of the heat and mass transfer phenomena between hot bubbles and a liquid is particularly relevant to the design of direct contact heating and evaporation systems such as submerged combustion equipment. In this process, exhaust gas from a burner is dispersed in a liquid to be heated or evaporated. Various models for the prediction of the temperature and vapor content of the bubbles as a function of their residence time in the liquid are presented. Based on the experimental measurements of the bubble size and of the heating time and evaporation rate in an actual submerged combustion system, models using spherical, ellipsoidal and spherical‐cap bubbles, with or without internal circulation, are discussed and assessed. It is found experimentally that the bubbles are of a spherical cap shape. Bubble equivalent diameters between 15 and 25 mm and bubble velocities between 0.4 and 1.2 m/s are observed. The proposed models are used to compute the heating time and evaporation rate of the bath during a submerged combustion operation; the predictions are then compared to the experimental values. The rigid spherical cap bubble model is found to predict satisfactorily the heat and mass exchanges between the bubbles and the liquid.
Prediction of minimum velocity and minimum bed pressure drop for gas‐solid fluidization in conical conduits
Authors: Singh R. K. , Suryanarayana A. , Roy G. K. 
Published: March 2009

AbstractExperimental investigations have been carried out for spherical and non‐spherical particles using beds comprised of single‐sized particles and mixtures in the size and particle density ranges of 439 to 1524 μm and 1303 to 4948 kg/m3, respectively. Five conical fluidizers with varying apex angles of 8.86, 14.77, 19.60, 32.0 and 43.2 degrees were used. Experimental values of minimum velocity and bed pressure drop with air as the fluidizing medium have been compared with their respective values obtained from different models available in the literature. Deviations for each chosen model have been presented.
Study of the gas circulation patterns in a uniflow cyclone
Authors: Gauther T. A. , Galtier P. , Briens C. L. , Crousle O. , Bergougnou M. A. 
Published: March 2009

AbstractA uniflow cyclone is being studied to achieve the separation of hot solids from the gaseous products of ultra‐rapid fluidized (URF) processes. An experimental method with hot wire probes was developed to study the gas flow around the gas outlet, where the solids exit. The vortex penetration in the solids exit could be determined. The presence of solids greatly reduced the vortex penetration in the uniflow cyclone. Restricting gas circulation around the gas outlet dramatically impaired the cyclone collection efficiency. Therefore, good cyclone performance requires a proper design below the gas outlet.
Plate wettability and droplet diameter in a pulsed perforated‐plate extraction column
Authors: Ikeda Hidematus , Suzuki Atsuyuki 
Published: March 2009

AbstractThe liquid‐liquid‐plate contact angles of several plate materials were measured using a “preferential wetting method” proposed by the authors. The adhesional work (ISL), calculated on the basis of contact angles was utilized to evaluate plate wettability. The experimental results indicate that different plate materials affect differently plate wettability. The plate wettability of stainless steel in an aqueous phase was observed to be different from that in an organic phase. The droplet diameter in the mixer‐settler region of operation of a pulsed perforated‐plate extraction column using several different plate materials, was measured. An empirical correlation of mean droplet diameter: dp = 0.222(af/lSL1/3)−0.13 is proposed except for alumina plates with dispersed aqueous phase operation.
Batch adsorption of trichlorotrifluoroethane (freon‐113) onto activated carbon — surface diffusivity and pore diffusivity
Authors: Kodama K. , Kaguei S. , Wakao N. 
Published: March 2009

AbstractActivated carbon was found more active than molécular sieve 13X and silica gel in adsorbing 1,1,2 trichloro‐1,2,2 trifluoroethane (CFE). Batch adsorption experiments were carried out with activated carbon to adsorb CFE at 15, 25 and 30°C. The adsorption isotherms of CFE on activated carbon were of the Langmuir type: q(C) = qm KC / (1 + KC) where qm and K were evaluated for the three temperatures. The measured bulk concentration‐time data were interpreted equally well with the surface diffusion model and the pore diffusion model; for the former model the surface diffusivity increased with increasing initial CFE concentration, and for the latter the pore diffusivity was independent upon the initial CFE concentration.
Momentum/heat transfer analogy for drag reducing fluids during turbulent boundary layer flow with small pressure gradients
Authors: Shenoy A. V. 
Published: March 2009

AbstractThere have been many attempts in the literature to develop analogies for momentum, heat and mass transfer to drag reducing fluids; however, none have considered the presence of a pressure gradient when formulating the analogies. In the present work, a momentum/heat transfer analogy has been developed under the influence of small pressure gradient for drag reducing fluids using the Nakayama et al. (1984) solution methodology for Newtonian fluids. The results of the present analysis have been found to compare well with existing theoretical expressions.
Settling of cylinders in power law liquids
Authors: Chhabra R. P. 
Published: March 2009

AbstractNew measurements on drag coefficient and wall effects on the free settling motion of cylinders in two shearthinning polymer solutions are reported. The ranges of conditions covered in this study are: 1 < Re∞∞ < 40; 0.25 < (LID) < 2; 0.079 < dID < 0.4, and n = 0.65 and 0.74. Both wall correction factor and drag coefficient results are in line with the Newtonian behavior provided a modified Reynolds number is used to represent the results.
Analysis of one dimensional grain model
Authors: Rao T. Rajeswara 
Published: March 2009

AbstractModel equations for slab type pellet consisting of spherical grains are solved numerically. It is shown that some of the generalised equations reported in the literature for slab type pellets with slab type grains and spherical pellets with spherical and slab type grains are equally applicable to a slab type pellet with spherical grains. A sensitivity analysis of the model to various parametric changes has been made and compared with experimental data on zinc sulphide oxidation to indicate the significance of the various assumptions. It is also shown that the model can be extended to solid‐consuming reactions as well. Experimental results on gasification of carbon with carbon dioxide reported in the literature were verified satisfactorily with the present model equations.
The design of experiments when there are errors in all the variables
Authors: Keeler Scott E. , Reilly Park M. 
Published: March 2009

AbstractThe Error‐in‐Variables Model (EVM) applies to a large class of problems in parameter estimation in which there is error in all the variables. This property makes it of more general applicability than the widely used technique of ordinary Least Squares. While there is a voluminous literature on EVM there is nothing on a general method for designing experiments when EVM applies. In this paper we present an extension of the concept of D‐optimality to provide such a general method. It is illustrated by applying it to the estimation of copolymer reactivity ratios and to fitting an ellipse.
Signal processing considerations for extrusion pressure measurement
Authors: Pabedinskas A. , Cluett W. R. 
Published: March 2009

AbstractThis paper presents some important aspects of pressure signal measurement in an extrusion system, including work that has been done to identify the types and causes of the pressure fluctuations using spectral analysis, and the steps taken to obtain reliable pressure measurements when digital data acquisition equipment is used. It is shown that pressure fluctuations associated with the extruder screw rotation may appear as lower frequency fluctuations in the sampled pressure signal. This well‐known phenomenon called aliasing must be reduced or eliminated in order to avoid making erroneous conclusions about the cause of the fluctuations. A combination analog‐digital anti‐aliasing filter has been designed and implemented on an extrusion system equipped with an In‐line Wedge Rheometer.
Spouting of two‐dimensional beds with draft plates
Authors: Kalwar M. I. , Raghavan G. S. V. , Mujumdar A. S. 
Published: March 2009

AbstractTwo slotted two‐dimensional spouted bed units with flexible bed dimensions were used with draft plates to study spouting pressure drop and minimum spouting superficial velocity. The data were collected while varying slant angle, spout width, separation distance, length of bed, height of bed, and size of bed (geometrical similarity) using shelled corn, soybean, and wheat. The variables which affect the spouting pressure drop and air flow through the beds are discussed. Empirical correlations are developed following the principles of dimensional analysis and similitude. The developed correlations agree closely with the collected data.
Pyrolysis with partial combustion of oil shale fines in a spouted bed
Authors: Lisbôa A. C. L. , Watkinson A. P. 
Published: March 2009

AbstractPyrolysis with partial combustion of oil shale fines from the Irati Formation in Brazil has been investigated in a 30 cm diameter spouted bed reactor. Experiments were carried out at atmospheric pressure and temperatures between 450 and 600°C. The oi] shale particle size was less than 6.35 mm. Spouting gas temperatures ranged from 20 to 565°C. Three inlet gas pipe diameters and two spouted bed heights were studied. Operation of the process was found to be stable over a wide range of test conditions. Results are presented for oil and gas quality, efficiency of retorting and overall performance of the plant.
The british coal spouted fluidised bed gasification process
Authors: Arnold M. S. T. J. , Gale J. J. , Laughlin M. K. 
Published: March 2009

AbstractBritish Coal Corporation has been developing an air‐blown spouted fluidised bed gasification process for the production of low calorific value fuel gas. Development of the gasifier at atmospheric pressure for the industrial market has established the commercial basis for a flexible gasification process, which can achieve coal conversion efficiencies of up to 95%. For larger‐scale use, a pressurised gasifier is under development as part of an integrated partial gasification combined cycle, coal‐fired, electricity generating system. Known as the British Coal Topping Cycle, the system offers significant advantages in terms of improved thermal efficiency, reduced generating costs and low environmental impact. The paper outlines the gasifier development programme for both applications.
Mixed convection heat and Mass transfer in a vertical channel with film evaporation
Authors: Yan Wei‐Mon 
Published: March 2009

AbstractNumerical results are presented for effects of latent heat transport associated with film vaporization on laminar mixed convection heat and mass transfer in a vertical channel with a half channel width b = 0.01 m. The influences of the inlet liquid mass flowrate and wall temperature on the film vaporization and the associated heat and mass transfer characteristics are examined for air‐water and air‐ethanol systems with gas Reynolds number Reg = 2000. Predicted results obtained by including transport in the liquid film are contrasted with those where liquid film transport is neglected, showing that the assumption of an extremely thin film made in Lin et al. (1988) and Yan and Lin (1989) is only valid for systems having small liquid mass flow rates. Additionally, it is found that the interfacial heat flux is predominantly determined by latent heat transfer connected with film evaporation.
Heterogeneous nucleation of organic vapours on a cold substrate
Authors: Shinagawa Hideo , Okuyama Kikuo , Kawamura Yuji 
Published: March 2009

AbstractThe heterogeneous phase transition of the organic vapours, cyclohexane and p‐xylene, on a cold substrate was observed by cooling the substrate at a slow rate under reduced pressure conditions. Either organic vapour at a vapour pressure lower than 130 Pa formed directly solid crystals but p‐xylene vapour at a higher vapour pressure formed liquid condensates with subsequent formation of solid crystals. The dependence of the critical supersaturation ratios on the critical temperatures and the physical properties of the organic vapours has been clarified by the equation derived on the basis of classical nucleation theory.
Effet de la pression sur la transition ruisselant‐pulsé dans les réacteurs catalytiques à lit fixe arrosé
Authors: Wild Gabriel , Midoux NoËL , Laurent AndrÉ , Larachi FaÏÇAl 
Published: March 2009

AbstractLes modèles théoriques et corrélations empiriques existants actuellement sont incapables de prévoir correctement ľinfluence de la pression sur le déplacement de la transition entre les régimes ruisselant et pulsé (Trp) dans les réacteurs catalytiques à lit fixe arrosé (Rclfa). Basé sur les données disponibles à ce jour de la Trp à haute pression, le diagramme de Charpentier modifié que nous proposons ici, constitue un moyen direct pour quantifier ľeffet de la pression dans le cas de systèmes non‐moussants.
A systematic approach for the efficient estimation of interaction parameters in equations of state using binary vle data
Authors: Englezos Peter , Kalogerakis Nicolas , Raj Bishnoi P. 
Published: March 2009

AbstractA systematic and computationally efficient approach for the estimation of the interaction parameters in equations of state using binary vapor liquid equilibrium (VLE) data is presented. Initially, the best set of interaction parameters is estimated by implicit least squares. Subsequently, the VLE calculations are performed using these parameters. Based on the quality of the fit it is decided whether these estimates suffice or implicit maximum likelihood estimation should be performed to obtain the statistically best values. Estimation subject to the liquid phase stability constraint is performed when erroneous phase behavior is computed. The approach is illustrated with typical examples.
Surface‐to‐suspension heat transfer model in lean gas–solid freeboard flow
Authors: Farag Ihab H. , Tsai Kun‐Yung 
Published: March 2009

AbstractHeat transfer in dense fluidized beds have been extensively studied. However, there is not much detailed information about the mechanism of surface‐to‐suspension heat transfer in the freeboard region. In the present work, a newly designed heating plate was used to measure the plate‐surface‐to‐particle‐suspension heat transfer coefficients in the freeboard.The experimental unit consisted of a 30 cm i.d. fluidized bed reactor packed with fluidized catalytic particles of mean particle size 90 μm. Three types of plate orientations were used to test directional effects of surface on heat transfer rate. Height of the freeboard was 171 cm, and the superficial gas velocity was varied from 0.28 to 0.64 m/s. Local solids concentrations in the freeboard were also obtained by a nozzle‐type sampling probe. Data on axial distribution of solids concentration were used to find out the solids kinematics in the freeboard region. Finally, a surface‐to‐suspension heat transfer model was developed to elucidate the surface to particle heat transfer mechanism in this lean phase system.The model is based on the transient gas‐convective heating of single particles when sliding over the heating plate and the assumption of instantaneous attachment–detachment equilibrium between particles and the plate surface.
A new constrained self‐tuning pid controller
Authors: Katende Edward , Jutan Arthur 
Published: March 2009

AbstractA new constrained self‐tuning PID controller is developed based on Clarke and Gawthrop's (1975) generalized minimum variance (GMV) controller. Convergence properties for the new algorithm are derived and the effect of the constraint parameter is evaluated. Extension of the controller to include more than the usual three PID parameters occurs naturally. No process model information is required for our algorithms except the dead time. This is an improvement over other algorithms which impose severe constraints on the process structure.The controller algorithm is tested on a variety of models using simulation as well as under experimental conditions. The algorithm is easy to implement and compares favourably with the more complex GMV controller.
Gas‐liauid mass transfer in non‐newtonian fluids in a tank stirred with a helical ribbon screw impeller
Authors: Tecante A. , Choplin L. 
Published: March 2009

AbstractOxygen transfer in aqueous solutions of CMC, xanthan gum, and polyacrylamide in a vessel equipped with a helical ribbon screw impeller and a multi‐orifice ring sparger was studied. The KLa values obtained were comparable to those reported for radial flow impellers, but they are more representative of the oxygen transfer in the bulk of the liquid because of a more homogeneous mixing and absence of dead zones. Dimensionless correlations including the effect of the physical properties of the fluids, and those of operating conditions were developed. A dimensionless correlation for each fluid is proposed.
Benzyl diethyl phosphite as a coke inhibitor during naphtha pyrolysis. tubular reactor studies
Authors: Chowdhury S. N. , Kunzru D. 
Published: March 2009

AbstractThe effectiveness of benzyl diethyl phosphite as a coke inhibitor during naphtha pyrolysis was investigated in a tubular reactor at 1073 K and atmospheric pressure. Significant reduction in the coking rate was achieved by adding benzyl diethyl phosphite to the feed. The effect of toluene, methylcyclohexane, l‐octene and carbon disulfide on the rate of coke formation was also investigated. Toluene enhanced the rate of coke formation significantly, whereas with methylcyclohexane and l‐octene the increase was less appreciable. Carbon disulphide decreased the amount of coke deposited initially, but with increasing run time the asymptotic coking rates were found to be higher than for straight‐run naphtha. The yields of propylene, 1,3‐butadiene and butenes increased on addition of carbon disulphide.
Analytical effectiveness factor calculations concerning product‐inhibited fermentations associated with biofilm growth and maintenance
Authors: Vanede C. J. , Bollen A. M. , Beenackers A. A. C. M. 
Published: March 2009

AbstractAn analytical reaction engineering model, recently presented by van Ede et al. (1992), which describes formation of inhibiting products associated with the growth of immobilized biofilms, is extended to describe simultaneous production associated with biofilm maintenance. The model accounts for both the metabolic rate controlling behaviour of an inhibitory product in the biofilm, and the effect of diffusion limitation in the transport of this product or a substrate, on the biofilm thickness.Simple criteria are presented to check the applicability of the model in the case of true Monod kinetics.As a potentially industrially important example, ethanol production by Zymomonas mobilis is treated.
Extension of hála's model to correlate isobaric vapor‐liquid equilibria containing calcium chloride
Authors: Kumagae Yoshio , Arai Yasuhiko 
Published: March 2009

AbstractIsobaric vapor‐liquid equilibria (VLE) of methanol‐water and methanol‐ethanol systems with calcium chloride at several concentrations were studied from the view point of the applicability of Hála's model which had been applied to correlate isothermal VLE of salt‐containing systems. Prediction of the VLE of the two isobaric systems was not satisfactory with the binary interaction parameters taken from the corresponding isothermal systems because of the different temperature range. However, it was found that the correlation of the isobaric systems was successful by adjusting solvent‐salt parameters. It was also found that the parameters obtained were independent of the salt concentration.
Prediction of carbon dioxide gas hydrate formation conditions in aqueous electrolyte solutions
Authors: Tse C. W. , Bishnoi P. R. 
Published: March 2009

AbstractA methodology for predicting the incipient equilibrium conditions for carbon dioxide gas hydrates in the presence of electrolytes such as NaCl, KCl and CaCl2 is presented. The method utilizes the statistical thermodynamics model of van der Waals and Platteeuw (1959) to describe the solid hydrate phase. Three different models were examined for the representation of the liquid phase: Chen and Evans (1986), Zuo and Guo (1991), and Aasberg‐Petersen et al. (1991). It was found that the model of Zuo and Guo (1991) gave the best results for predicting incipient CO2 gas hydrate conditions in aqueous single salt solutions. The model was then extended for prediction of CO2 gas hydrates in mixed salts solutions. The predictions agree very well with experimental data.