bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modeling of the free flight region of a cyclone transferred arc plasma reactor
Authors: Chen L. S. , Munz R. J. 
Published: March 2009

AbstractThe Plasmacan cyclone transferred arc plasma furnace seems ideally suited for the treatment of fine refractory powders to produce a consolidated liquid product. In this furnace, particles are pneumatically injected tangentially near the wall of a cylindrical sleeve while an arc is struck along the central axis of the sleeve. A simple model has been developed to examine the behaviour of the injected particles in the entrance region of the furnace up to the point where the particles reach their melting point and form the molten film. Three‐dimensional equations of particle motion are solved to compute particle trajectories, given gas temperature and velocity fields in the furnace. The location of the first appearance of the molten film is computed under a variety of operating conditions for a laboratory scale furnace.
Liquid phase synthesis of methyl tert‐butyl ether catalyzed by ion exchange resin
Authors: Subramaniam C. , Bhatia S. 
Published: March 2009

AbstractSynthesis of methyl tertiary butyl ether (MTBE) from methanol and isobutene was studied using macroporous cation exchange resin, Amberlyst 15 in the hydrogen form, as a catalyst in the temperature range of 313‐328 K. The reaction was carried out in a batch reactor at a pressure of one atmosphere in the liquid phase. A high degree of agitation was maintained in order to eliminate film diffusion resistance. The effect of catalyst loading, catalyst particle size and reaction temperature on reaction rate were studied. The reaction rate increased with increase in catalyst concentration and reaction temperature. Resin particle size had virtually no effect on the rate under the experimental conditions.The reaction rate data were analysed using homogeneous kinetics and heterogeneous models based upon Langmuir‐Hinshelwood rate expressions. The apparent activation energies using homogeneous and heterogeneous models were determined and found as 79.0 kJ/mol and 76.7 kJ/mol respectively.
Performance of a large scale packed recirculating reactor for homogeneous catalytic oxidation of car‐3‐ene
Authors: Mukesh D. , Gopalkrishnan K. S. 
Published: March 2009

AbstractAutooxidation of car‐3‐ene was carried out in a large scale packed recirculating reactor, where the catalyst cobalt acetylacetonate and the liquid were recirculated and sprayed on top of an inert packing. Gas is introduced from the bottom. The mass transfer parameters and mixing characteristics of the reactor were determined. The effect of catalyst quantity, operating pressure on car‐3‐ene conversion, and selectivity for various products were studied. The reaction system was mathematically modelled, and the simulation compared with the observed behaviour. The rate constants of the elementary reaction steps had been determined separately in a laboratory reactor.
The surface renewal model of wall turbulence for boundary layer flow with transpiration
Authors: Thomas L. C. , Loughlin K. F. 
Published: March 2009

AbstractThe object of this paper is to develop and evaluate the basic surface renewal modeling approach for transpired turbulent boundary layer flows. Using a simple form of the surface renewal model in conjunction with the standard mixing length representation of the turbulent core, calculations are established for the dimensionless burst frequency s+, and distributions in velocity u+ within the inner region as a function of transpiration rate v+ and pressure gradient P+.
Initial fouling of nontoxic coatings in fresh, brackish, and sea water
Authors: Meyer A. E. , Baier R. E. , King R. W. 
Published: March 2009

AbstractObjectives of this project were to evaluate benefits — over the short term — that might derive from control of the surface properties of materials used in energy transfer devices; and to identify preferred ranges of surface parameters that might be specified to minimize deposits of biological fouling known to deteriorate energy exchange efficiencies in seawater, brackish water, and freshwater systems. By modifying the surface chemistry and surface energy of test plates with very thin coatings (nontoxic) and examining the acquired films at various time intervals, the earliest events of biofouling caused by macromolecules and microbial organisms were defined. Overall, the results were remarkably similar for all systems tested in showing that deliberate modification of the initial material surface qualities can significantly reduce the retention of biofouling layers.
On the examination of recycle on heat (and mass) transfer in concentric tubes
Authors: Yeh Ho‐Ming , Tsai Shau‐Wei , Hsiey Mean‐Chu 
Published: March 2009

AbstractThe effect of recycle on heat (and mass) transfer in concentric circular tubes has been investigated by finite difference methods. Theoretical results show that recycle can enhance the heat transfer rate for large Graetz numbers compared with that in an open tube (without an inner tube inserted and without recycle). Competition between a preheating effect and a residence‐time effect can be used to explain the heat transfer behavior. The heat transfer rate can be further augmented, with nearly no increase in total pressure drop, by employing flow pattern B instead of flow pattern A.
Moment analysis of nonlinear systems: A kinetic study
Authors: Hwang Bing Joe , Chou Tse‐Chuan 
Published: March 2009

AbstractThe moment method has been used extensively to evaluate parameters of chemical reactions, adsorption or reactor design, but only for linear systems. Moment analysis of nonlinear systems is studied in the present work. A general complicated reaction system involving nonlinear terms in a batch slurry reactor is chosen to demonstrate the method. The first and second improved solutions in Laplace domain and moment expressions are obtained. The improved solution can converge to the exact solution if the iterative procedures are repeated several times.
The importance of temperature rise time in pyrolysis kinetic studies
Authors: Rastogi Ashutosh , Svrcek William Y. , Behie Leo A. 
Published: March 2009

AbstractThe measurement of the kinetics of fast chemical reactions, such as hydrocarbon pyrolysis, is often hampered by limitations of the experimental reactor. To overcome problems in getting to reaction temperature, a micro‐reactor system has been developed with temperature rise times (TRT) in the millisecond range. Data is presented for the dynamic response of a Curie Point pyrolyser along with a computer simulation of how the gas‐filled micro‐reactor would respond. The importance of temperature rise time is clearly demonstrated by the computer simulations of propane and naphtha pyrolysis in the temperature range of 600°C and 1100°C.
High pressure phase equilibria in the carbon dioxide ‐ n‐Hexadecane and carbon dioxide — water systems
Authors: D'souza Rupert , Patrick Jennie R. , Teja Amyn S. 
Published: March 2009

AbstractPhase equilibria in the carbon dioxide ‐ n‐hexadecane and carbon dioxide – water systems have been measured at temperatures between 314 K and 353 K and pressures between 8.53 and 16.12 MPa. The results have been correlated using two cubic equations of state and also compared with measurements reported in the literature.
Viscosities of binary liquid mixtures of cyclohexanone with alkanes, benzene, toluene and tetrachloromethane at 298.15 K
Authors: Rao K. Purna Chandra , Reddy K. S. 
Published: March 2009

AbstractViscosities for the binary liquid mixtures of cyclohexanone with n‐hexane, n‐heptane, 2, 2, 4‐trimethylpentane, benzene, toluene and tetrachloromethane have been determined at 298.15 K. The deviation in viscosity from the ideal law is negative in all the systems except in the system, cyclohexanone with tetrachloromethane. In this system excess viscosity exhibits a positive deviation over the entire range of mole fraction. The results have been interpreted in terms of molecular interactions, and of difference in size and shape of components. The theoretical excess viscosities have been calculated from absolute reaction rate theory and free volume theory of flow by making use of the Bloomfield and Dewan relations. Theoretical excess viscosities are in qualitative agreement with experimental results for four out of the six systems examined.
End wall effects on thermal stratification and heat transfer in a vertical enclosure with offset partitions
Authors: Jetli R. , Acharya S. 
Published: March 2009

AbstractEnd wall effects on thermal stratification and heat transfer in a vertical enclosure with offset partitions has been studied by numerically solving the governing differential equations. Two limiting end wall conditions are investigated — adiabatic end walls and perfectly conducting end walls. Two offset partition positions and three partition heights are considered. It is observed that with adiabatic end walls, the heat transfer from the vertical hot and cold walls is always greater. The effect of end wall conditions is most significant when the top partition is offset toward the cold wall and the bottom partition toward the hot wall. In this position strong thermal stratification in the core is observed. When the direction of offset is reversed, i.e., top partition is moved closer to the hot wall and the bottom partition closer to the cold wall, strong stratification effects are noted in the partition‐near side wall region. Adiabatic end wall conditions promote these stratification effects.
Gas absorption with exothermic bimolecular reaction in a thin liquid film: Fast reactions
Authors: Bhattacharya A. , Gholap R. V. , Chaudhari R. V. 
Published: March 2009

AbstractA problem of gas absorption with a fast nonisothermal bimolecular reaction in a thin liquid film has been analysed. Approximate analytical solutions for the interfacial temperature rise and enhancement factor have been derived incorporating the influence of depletion of liquid reactant concentration at the interface. The effects of heat generation, heat dissipation and reaction rate parameters on enhancement factor and interfacial temperature rise have been discussed. For a certain range of parameters, multiple steady state solutions of enhancement factor and interfacial temperature rise are observed. Another interesting observation is that as the value of a dimensionless parameter ϕ increases, the enhancement factor approaches its instantaneous asymptote which is the same as that for the isothermal case in an instantaneous regime. The analysis presented here is simple and avoids complex numerical computations and it is likely to be useful in design applications.
Isobaric vapor‐liquid equilibrium and liquid‐phase enthalpy of mixing data for the binary mixtures of m‐ or p‐Xylene with cyclohexanol
Authors: Comelli Fabio , Francesconi Romolo , Arcelli Antonio 
Published: March 2009

AbstractIsobaric vapor‐liquid equilibrium data and liquid‐phase enthalpy of mixing are investigated for the binary mixtures of m‐ or p‐xylene with cyclohexanol. Allowance for self‐association of the cyclic alcohol is made when assessing the thermodynamic consistency of the experimental data.Activity coefficients are correlated to mole fractions through the Wilson Equation, the parameters of which are obtained by the method of maximum likelihood and compared with the ones given by the conventional unweighted least‐squares procedure.
Ethylene recovery from low grade gas stream by adsorption on zeolites and controlled desorption
Authors: Mao Raymond Le Van , Mclaughlin Gerald P. 
Published: March 2009

AbstractCarbon dioxide was partially removed from a nitrogen stream, which also contained some ethylene, by adsorption on a 4A (Na‐A) zeolite. The treated nitrogen stream was then passed over a 13X (Na‐X) zeolite bed upon which ethylene and any remaining carbon dioxide were adsorbed. Ethylene was recovered by desorption at 68 Pa pressure into a slow flow of nitrogen as stripping gas. The ethylene concentration in the extracted gas was extremely dependent on the nitrogen flow‐rate, whereas the concentration of carbon dioxide remained practically constant. Thus, it was possible to obtain a gas mixture greatly enriched in ethylene with a reasonably low content of carbon dioxide.
Rheological properties of polymer‐added lubricating oils
Authors: Derdouri A. , Ait‐Kadi A. , Carreau P. J. 
Published: March 2009

AbstractRheological measurements of polyisobutylene solutions are presented. A mineral oil of low viscosity has been used as solvent. The combined effects of concentration, molecular weight and temperature were studied. It is found that the rheological data, when plotted as N1λE/(η‐ηs) versus λEγ fall on a master curve over several decades of the dimensionless shear rate, irrespective of temperature, polymer concentration and molecular weight. The findings of this work can be used to address the problem of hydrodynamic lubrication of a journal bearing using a viscoelastic lubricant.
Dissolved oxygen removal by combination with hydrogen using wetproofed catalysts
Authors: Suppiah S. , Kutchcoskie K. J. , Balakrishnan P. V. , Chuang K. T. 
Published: March 2009

AbstractDissolved oxygen in water at parts per million levels could be reduced to a few parts per billion by reaction with hydrogen using Pt catalysts supported on carbon and stainless steel in random and structured bed configurations. The carbon supported catalyst was Teflon coated to wetproof it. Both gas phase and liquid phase reactions occurred simultaneously under trickle bed operation, resulting in higher oxygen removal efficiency for this mode of operation than for the liquid‐filled condition. The structured catalyst bed yielded greater hydraulic capacity than the random bed, and with wetproofed catalyst it gave the best oxygen removal efficiency. Since the gas phase reaction rate could be increased by reducing the wetted fraction of the catalyst through wetproofing, wetproofed catalysts offer a unique advantage over conventional hydrophilic catalysts.
Vapor liquid equilibrium data for alcohol n‐Amylamine binary systems at 333.15 K. Reduction of the experimental data by a novel model‐free method
Authors: Abusleme J. A. , Vera J. H. 
Published: March 2009

AbstractVapor liquid equilibrium measurements for the binary systems of n‐amylamine with methanol, ethanol and 1‐propanol at 333.15 K are reported. The measurements were made in a static equilibrium cell of the Van Ness type and the experimental data were reduced using a model‐free method. This model‐free method is an adaptation of the method of Mixon et al. in which a material balance is introduced to correct for the mols of the gas phase. Second virial coefficients of n‐amylamine and cross second virial coefficients for the binary systems were measured in this work and parameters for the Tsonoupolos correlation are reported.
Equilibrium characteristics for the extraction of cobalt and nickel into di(2‐ethylhexyl) phosphoric acid
Authors: Golding J. A. , Barclay C. D. 
Published: March 2009

AbstractThe liquid‐liquid extraction of cobalt and nickel from aqueous sulphate solutions into di(2‐ethylhexyl) phosphoric acid, DZEHPA, has been investigated at 25°C and 60°C. The system studied was made up as follows: the aqueous phase‐cobalt and nickel dphates; the organic phase‐20% D2EHPA, 75% Esso solvent DX3641 and 5% tri‐butyl phosphate. Analogies to vapour‐liquid equilibria were made to develop three methods to correlate the binary equilibrium data, namely: 1) a delta Y method, 2) a method based on the correlation of solvent free mole fractions in both phases and 3) a “pseudo activity” coefficient or pseudo gamma method, γAB.The methods were evaluated as to their suitability for the prediction of binary isotherms. The delta Y and pseudo gamma methods were found to give the best results.
A study of CrO vapor decomposition in approximated isothermal RF plasma reactors
Authors: Meubus P. , Huczko A. 
Published: March 2009

AbstractA simplified RF plasma reaction model has been used for describing the thermal decomposition reaction of chromium oxide (CrO), using an argon RF plasma operated at 2.7 kW. A set of 3 approximated isothermal reactors in series were defined for this purpose within the RF torch. The conversion rate curves were obtained for the respective average isothermal temperatures 4250 K, 3500 K and 2950 K. Reaction order and reaction rate constant were determined at each temperature.Based on the values obtained for the reaction orders, it appears that the kinetics process involved is similar at 2950 K and 3500 K, while a distinctly different process occurs at 4250 K. Assuming that the two former reactions show an Arrhenius type behavior, an activation energy value has been derived, valid between 2900 K and 3500 K.The activation energy for the CrO decomposition reaction has been calculated on the basis of an Eyring and Polanyi model. The calculated and experimental results differ by about 20%. The main point responsible for the large reaction rate constant increase observed at 4250 K is the drastic change of the pre‐exponential factor in the Arrhenius equation.
Rey‐zeolite and silica‐alumina mixed support for hydrotreating heavy gas oil
Authors: Sambi Inderjit S. , Mann Ranveer S. 
Published: March 2009

AbstractRare earth exchangedY‐type zeolite (REY‐zeolite) was dispersed in a silica‐alumina gel to prepare catalyst supports with better hydrogenolysis activity. Such support material showed improved hydrotreating properties compared to commercial catalysts, especially for heavy gas oils. Statistical experimental designs used to optimize the composition of such mixed supports suggested a composition of 10 wt.% silica, 25 wt.% zeolite and 65 wt.% alumina as optimum for hydrotreating a heavy gas oil (343°C to 525°C fraction) obtained from hydrocracking of Athabasca bitumen. The kinetic parameters were then evolved for the optimum catalyst.
Sequential statistical design strategy in a kinetic study of propylene oxidation
Authors: Tan H. S. , Bacon D. W. , Downie J. 
Published: March 2009

AbstractA sequential design strategy was used to direct an experimental kinetic study of propylene oxidation over bismuth molybdate. Two statistical criteria were used to design experiments. The first is a joint criterion for the dual problem of model discrimination and parameter estimation which was proposed by Hill et al. (1968), but which to the best of our knowledge has not been tested in an experimental program. Using this joint criterion design, it was demonstrated that both the objectives of model discrimination and precise parameter estimation were effectively accomplished. After model discrimination had been achieved, a design strategy for further improvement in parameter precision was found, as expected, to be effective for that purpose.
Maximizing the capacity and life of depth‐type filters
Authors: Dullien F. A. L. 
Published: March 2009

AbstractAn analytical expression has been derived for the variation of the filtration coefficient of depth‐type filters with fractional depth from the downstream to the upstream face of the medium which satisfies the condition of identical retention in every cross‐section of the medium. A numerical example has been worked out for a fibrous filter where the porosity of the medium was varied to comply with the required variation of the filtration coefficient. It has been shown also that a filter consisting of three uniform layers of different porosities may adequately approximate the required continuous variation of the filtration coefficient. After a retention of 10% pore volume of dust the permeability of the three‐layer medium is about 4 times greater than that of a medium of uniform initial porosity characterized by identical initial collection efficiency, thickness and fiber diameter.
La modélisation de la turbulence dans une enceinte avec ouvertures et sources chaudes localisées
Authors: Dupuis Marc , Dernedde Edgar , Methot Jean‐Claude 
Published: March 2009

AbstractLa circulation de l'air dans une enceinte avec plusieurs ouvertures et sources chaudes localisées a été étudiée à l'aide d'un modèle mathématique. Après plusieurs comparaisons avec les circulations observées dans une maquette, on a constaté qu'un modèle de turbulence devait ětre introduit pour améliorer la simulation mathématique. Deux modèles de turbulence, basés sur le modèle algébrique et sur le modèle différentiel (K‐ϵ‐G) de la viscosité turbulente, ont fait l'objet d'investigations. Le modèle différentiel a apporté peu d'amélioration aux résultats et a augmenté de beaucoup le coüt d'opération par rapport au modèle algébrique. L'utilisation du modèle différentiel n'était donc pas justifiée pour ces simulations.L'effet combiné de la convection forcée à travers l'enceinte et de la convection naturelle au voisinage des sources chaudes, a été simulé dans le but d'étudier la circulation de l'air et de la température dans une salle de cuves d'électrolyse de l'aluminium.
Analysis of several methods to determine the activity of water in solutions of strong electrolytes
Authors: Correa H. A. , Vega R. E. 
Published: March 2009

AbstractThe methods of Zdanovskii‐Stokes‐Robinson (ZSR), Reilly‐Wood‐Robinson (RWR), Pitzer and Correa, to determine water activity in ternary solutions of electrolytes from data for water activity in binary solutions, were analysed. In addition, the first two methods were used to estimate the activity of water in supersaturated binary solutions using data from ternary solutions. Also, the equation of Correa for binary solutions was extrapolated to calculate the activity of water at supersaturation.The methods were tested using the experimental data (at 25°C) for nine ternary systems, with a common ion, involving the following ions: Li+, Na+, K+, Ca++, Mg++, Cl− and NO3−. Zdanovskii's method gave the best estimations of water activity in ternary systems. The method of Correa gave smaller standard deviations than the methods of Pitzer and RWR with the advantage that its application is simpler. For binary solutions at supersaturation, Correa's method gave better results than the method of ZSR and this, in turn, yielded smaller deviations than the RWR method.
Self oscillation phenomena of turbulent jets in a channel
Authors: Murai Kazuhiro , Kawashima Yosuke , Nakanishi Shigeyasu , Taga Masao 
Published: March 2009

AbstractA new method based on the Coanda effect for self oscillation of a circular jet bounded by rectangular enclosure is suggested. The experiments in both air and water reveal regions of stable oscillation wherein relationships are obtained between the Strouhal number and the shape factor of the channel.This oscillation method can also be used to mix different liquids in a vessel. For such applications, an improvement of mixing by oscillation is shown by means of a residual concentration diagram for a salt solution.
Oxidation kinetics of anthracene with nitrogen dioxide in acetic acid
Authors: Rodriguez F. , Tijero J. F. 
Published: March 2009

AbstractKinetics of liquid‐phase oxidation of anthracene to anthraquinone with nitrogen dioxide in acetic acid as solvent has been studied. The reaction takes place through the anthrone as intermediate compound. The first and second reactions are first order with respect to anthracene and anthrone concentration, respectively. The values of the rate constants in the temperature range 60–95°C have been reported.According to the reaction system developed, an industrial process for the manufacture of anthraquinone of high purity has been proposed.