bluuebunny/crossref_metadata_2025_split huggingface dataset:
The influence of viscous interaction on the diffusional deposition of particles
Authors: Dahneke Barton 
Published: March 2009

AbstractViscous interaction may prevent or retard diffusional deposition of fluid‐borne particles and droplets onto a collecting surface. The possible importance of viscous interaction has been recognized in the literature(1–3), but quantitative results which demonstrate the importance of viscous interaction are scant. Rather, the scant reported evidence is confusing. This paper reports the results of a theoretical investigation of the influence of viscous interaction on diffusional deposition of particles. The results show negligible influence in gaseous media, but sometimes significant retardation in liquid media, especially if electrical double layers also retard deposition.
Fluid flow pattern, minimum spouting velocity and pressure drop in spouted beds
Authors: Grbavčíc Ž. B. , Vukovíc D. V. , Zdanski F. K. , Littman H. 
Published: March 2009

AbstractThis study extends the theory of Mamuro and Hattori to beds of less than the maximum spoutable height. The new model gives predictions for the fluid flow pattern, minimum spouting velocity and spouting pressure drop which are in agreement both with experimental data on beds spouted with air and water (obtained in this study) and with literature data.A correlation for Hm in water spouted beds of spherical glass particles is also presented.
Frequency response of liquid fluidized systems. Part II Effect of liquid viscosity
Authors: Mehta S. C. , Shemilt L. W. 
Published: March 2009

AbstractThe imperfect pulse response technique, employing two measurement points, has been applied to the characterization of fluid mixing in systems where 0.5 mm glass beads are fluidized by liquids of viscosity (0.56 to 7.74 cp.) for bed porosities from 0.45 to 0.95. The frequency content of the input pulses was kept relatively high by experimenetal techniques. Frequency responses were determined from the measured residence time distributions. Axial dispersion coefficients for the axial dispersed plug flow (ADPF) model were calculated by moments and by frequency domain analysis, with considerable discrepancies at high degrees of mixing. Parameters for a time‐delay timedelay time‐constant (TDTC) model have also been estimated. A correlation for the significant time‐delay parameter has been developed for the range of viscosities and porosities. While both models can reasonably predict the frequency response, the TDTC model shows somewhat lower deviations and has the major advantage of predictable parameters through the correlation presented.
Adsorption of binary liquid‐phase hydrocarbon mixtures on arctic terrain
Authors: Moore J. P. , Phillips C. R. , Tombalakian A. S. 
Published: March 2009

AbstractAdsorption isotherms for the sorption of various binary liquid‐phase hydrocarbon mixtures on Arctic terrain were determined. The terrain was classified into three distinct layers, moss, detritus, and clay. The sequence of mass loading (g of hydrocarbon adsorbed/g of terrain) for each layer, and hence for the total terrain, was found to be the same, that is, nC16 > n‐C10 > p‐xylene > benzene > n‐C5, determined from liquid phase adsorption from binary systems in which n‐C10 was one component The behaviour of the Arctic terrain in the binary hydrocarbon mixtures investigated could be described by Freundlich adsorption isotherms. The extent of adsorption increases with the organic content of the terrain, and factors which determined adsorption appear to be physical in nature. For the hydrocarbons studied, the higher molecular weight hydrocarbon was ferentially adsorbed.
Axial dispersion in a reciprocating plate extraction column
Authors: Kim S. D. , Baird M. H. I. 
Published: March 2009

AbstractAxial dispersion coefficients have been measured in the continuous phase of a 5 cm diameter reciprocating plate extraction column. The measurements were made by observing the course of an instantaneous chemical reaction between acid and base in the continuous phase, using phenolphthalein as indicator. The data for single‐phase operation have been correlated in terms of amplitude and frequency of reciprocation, and spacing between plates. A similar correlation applies for liquid‐liquid operation under intense agitation. At low agitation rates, and for gas‐liquid operation, the dispersion coefficient depends strongly on the flow rate of dispersed phase.
Hydrogenolysis of propane on supported ruthenium. Effect of pressure
Authors: Anderson Robert B. , Tsjeng Po K. 
Published: March 2009

AbstractThe hydrogenolysis of propane on ruthenium‐on‐alumina was studied at 112° to 150° and 1.1 to 7.1 atm. abs. in a Carberry reactor. The simple power rate equation, that is usually employed for hydrogenolysis, was found to lack the proper mathematical form for representing the present data. Although the equation was adequate for fitting results at a given pressure, it failed to fit data taken at several pressures. The rate decreased with operating pressure to the −2.3 power, but the power equation predicted pressure exponents of −1. to −1.5. Therefore, a number of more complicated rate equations was tried. An acceptable equation involved a 2‐site mechanism for reaction of a dissociatively chemisorbed C3 species with appreciable coverages of the metal surface by dissociatively chemisorbed hydrogen and physically adsorbed propane.Ethane produced in the initial reaction of propane splits about 1% as fast as propane, and as pressure is increased, splitting of ethane decreases more rapidly than the hydrogenolysis of propane. Selectivity equations indicate that the rate of dissociative chemisorption of ethane is about 2% of that of propane, and that this factor largely determines the rates of hydrogenolysis of ethane and propane.
The analysis of data from recirculation reactors
Authors: Boag I. F. , Bacon D. W. , Downie J. 
Published: March 2009

AbstractA critical assessment is made of a commonly used procedure for estimating the kinetic parameters in a catalytic rate model using data obtained in a recirculation reactor. Serious deficiencies in this procedure are identified, and an alternative estimation scheme is proposed.The component mass balance equations in a recirculation reactor involve no differentiation or integration, and therefore the estimation of kinetic parameters appears to be simpler than the corresponding task with integral reactor data. However, a detailed examination shows that this is not the case, and that the effort involved in correctly estimating the parameters and their covariance matrix may not be significantly different for the two reactor types. Data obtained by Boag et al(10) from the vanadia‐catalysed gas‐phase oxidation of o‐xyleue in a recirculation reactor are used to demonstrate the differences between the parameter estimation procedure in common use and the procedure recommended in this paper.
Mass transfer from crystalline surfaces in a turbulent impinging jet. part 2: Erosion and diffusional transfer
Authors: Giralt Francesc , Trass Olev 
Published: March 2009

AbstractSimultaneous erosion and diffusional transfer from transcinnamic acid coatings in submerged, axisymmetric, impinging jets of water has been studied at a Reynolds number of 100,000 and a nozzle height of 8 diameters. The concentration driving force was varied from zero to the acid solubility value. For low transfer rates roughness development was small and the two transfer modes were additive. At higher dissolution rates, however, diffusion enhanced erosion by loosening surface grains. This loosening action was largest in the impingement region where large surface roughness developed and further enhanced the high dissolution rates and subsequent interactions.
Mass transfer in a ternary liquid‐liquid system
Authors: Cullinan Harry T. , Ram S. K. 
Published: March 2009

AbstractIsothermal mass transfer is studied in the partially miscible system, acetone‐glycerol‐water, using a modified stirred extraction cell of the Lewis type. Mass transfer rates between an unsaturated light phase and an effectively saturated heavy phase are determined. From such data, the partial mass transfer coefficients in the light phase can be calculated. The results confirm that, during such ternary extraction processes, the rate of mass transfer of a given constituent can depend appreciably on the driving forces of the other diffusing species.
Alumina trihydrate crystallization. Part 2. A model of agglomeration
Authors: Halfon A. , Kaliaguine S. 
Published: March 2009

AbstractIn the second part of this paper on the kinetics of crystallization of aluminum trihydroxide from caustic aluminate solutions, interest is specially focused on the analysis of crystal size distribution as a function of time, in an isothermal batch crystallizer.Breakdown and agglomeration are shown to affect these curves simultaneously. While only qualitative information on breakdown was obtained, agglomeration could be isolated experimentally. Its rate was measured and fitted to a kinetic model which pictures agglomeration as the result of binary collisions between particles.
Research on valve trays. Hydraulic performance in the air‐water system
Authors: Piqueur H. , Verhoeye L. 
Published: March 2009

AbstractThe entrainment and the pressure drop were studied in a 30 cm distillation column with three valve trays. Three industrial types of valves were investigated using an air‐water system. The air rate varied from 100 m3/h to 800 m3/h and the liquid rate from 100 1/h to 1.000 1/h.Four weir heights (4.5, 6.0, 7.5, 9.0 cm) and four plate spacings (30, 37.5, 42.5, 50 cm) were used.Equations for the amount of entrainment and the pressure drop were derived and compared to previous results from the literature.
Charged membrane ultrafiltration of heavy metal salts: Application to metal recovery and water reuse
Authors: Bhattacharyya Dibakar , Schaaf David P. , Grieves Robert B. 
Published: March 2009

AbstractAn experimental investigation is presented of the thin‐channel ultrafiltration of 0.6 × 10−3 M to 15.0 × 10−3 M aqueous solutions of Cu2+, Ni2+, or Zn2+ sulfate or chloride salts through a negatively‐charged, non‐cellulosic membrane. Multi‐salt solutions and the actual rinse water from a Watts‐type‐nickel‐plating process are also ultrafiltered. The membrane provides a Ni2+ rejection of 0.83 and water flux of 1.0 × 103 cm/sec (23 gal/ft2 day) at a transmembrane pressure difference of 4.0 × 105 N/m2 (3.9 atm). The membrane rejection and water flux data are utilized in a computer simulation procedure for scale‐up to a multi‐module, two‐staged process for the closed‐loop operation of a plating plant.
Wet oxidation of active carbon
Authors: Charest F. , Chornet E. 
Published: March 2009

AbstractAs a preliminary step to studies on the regeneration of active carbon, its wet oxidation has been followed in order to obtain information about the different parameters involved: agitation, temperature and pressure.The oxidation reaction takes place in the liquid phase and it does not proceed at significant rates below 200°C, even with high initial oxygen pressures. The oxidation proceeds rapidly beyond 275°C at pressures as low as 30 atm. The only detectable reaction product is carbon dioxide.Although mass transfer effects are minimized at stirring speeds higher than 400 rpm, a visible abrasion of the carbon was apparent beyond 300 rpm. Consequently, the study was carried out at around 200 rpm. Mass transfer effects had to he considered then. Estimation of the different transfer coefficients was done from the experiments and through existing correlations. In this way the kinetics could be obtained. The rate of reaction can be represented by a first order kinetic expression.Comparison of the rates has been done at fixed conversions. The intrinsic rate constant has a surprisingly low activation energy of 8.4 Kcal/mole suggesting that the oxidation reaction proceeds via a free radical mechanism. The overall rates show a maximum at conversions varying between 0.10 and 0.40. The specific surface area decreases regularly with reaction time, indicating that the reaction takes place throughout the particle.
An experimental technique for determining the significance of intraparticle diffusion in an aging catalyst
Authors: Best Donald A. , Wojciechowski Bohdan W. 
Published: March 2009

AbstractThe effects of simultaneous decay and diffusion on a first order reactiion have been investigated. Two limiting types of behaviour are observed. In the first, cumulative conversion on diffusion limited catalysts is shown to behave in a manner opposite to that expected if the catalyst were non‐aging, in that conversion decreases with decreasing particle size. The other extreme shows behaviour consistent with that observed on a non‐decaying catalyst; that is, conversion increases with decreasing catalyst size. Experimental evidence for such behaviour is observed with cumene cracking and gas oil cracking, both on zeolite catalysts.As a consequence of the above observations, it is proposed that a new test involving experimentation at constant cat/oil ratio and over a range of space velocities be used to determine the significance of intraparticle diffusion on a catalyst subject to decay.
Transient behaviour of a non‐ideal tubular reactor
Authors: Nigam K. D. P. , Vasudeva K. 
Published: March 2009

AbstractExperimental data are reported for the unsteady state behaviour of a laminar flow reactor with first order homogeneous liquid phase reaction. The data are in agreement with the predictions of the dispersion model, using previously reported reaction‐dependent dispersion coefficients which directly gives the bulk mean concentration. The use of proper boundary conditions, ignored in a recent paper on this topic(19), is found to significantly influence the predictions. Unlike the conclusion drawn in(19) it is shown that the Taylor model is unable to correctly predict the reactor length for fast reactions even for high conversions.
The measurement and prediction of the solubility of mixtures of carbon dioxide and hydrogen sulphide in a 2.5 N monoethanolamine solution
Authors: Lee J. I. , Otto F. D. , Mather A. E. 
Published: March 2009

AbstractThe solubility of mixtures of carbon dioxide and hydrogen sulphide in a 2.5 N monoethanolamine solution has been determined at temperatures of 40°C and 100°C. Partial pressures of CO2 ranged from 0.7 to 5630 kPa, while partial pressures of H2S ranged from 0.7 to 3780 kPa. The present results extend the published data on this system which were limited to partial pressures below 200 kPa. The results have been compared with two methods of prediction based upon a thermodynamic model.
Flow patterns and mass transfer rates in fluidized bed ion exchange equipment
Authors: Slater M.J. , Lucas B. H. 
Published: March 2009

AbstractThe axial mixing of ion exchange resin and liquid in fluidized beds is modelled by a series of well‐mixed cells for the resin and an equal or larger number of mixed cells for the liquid. Concentration breakthrough curves are calculated using this mixing model, assuming finite mass transfer kinetics and irreversible equilibrium. The model is used to describe mixing patterns and kinetics in static fluidized beds (no resin flow); the information so obtained can be used to design continuous and periodic flow counter‐current fluidized bed ion exchange systems.
The effects of surface viscosity on the axisymmetric drainage of planar liquid films
Authors: Barber A. D. , Hartland S. 
Published: March 2009

AbstractThe Reynolds equation is extended to allow for the effects of shear and dilational surface viscosities on the axisymmetric drainage of planar films. It is shown that the number of immobile surfaces, n, may be expected to decrease with increasing film radius and bulk viscosity and with decreasing film thickness and surface viscosity, as observed experimentally. The predicted rate of film thinning agrees well with available experimental results.
Thermal energy storage in inorganic salts
Authors: Verma Arun , Johnson Keith E. , Sherman E. O. 
Published: March 2009

AbstractThe work involved studying the potential of Na2SO4, NaCl, KCl, CaCl2 and some eutectic mixtures of inorganic salt for storing thermal energy. Heat storage materials have wide application in devices such as “off‐peak” space heating furnaces. Data reveal Na2SO4 to be a better heat storage material than other salts as well as conventional heat storage materials because of its dimorphic nature and high heat of transition. It is estimated that less than 0.29 m3 of Na2SO4 would be required for heating a normal sized house on the Canadian Prairies.
Kinetics of o‐Xylene oxidation over sintered vanadium pentoxide in a spinning catalyst basket reactor
Authors: Pant Gopinath S. , Chanda Manas 
Published: March 2009

AbstractKinetics of vapor phase oxidation of o‐xylene has been studied over sintered and compacted vanadium pentoxide in a continuous stirred tank catalytic reactor in the temperature range of 450–517°C at atmospheric pressure. The major product obtained is phthalic anhydride. The other products are maleic anhydride and carbon dioxide.The reaction rate data are well represented (with average absolute deviation less than 6%) by the following expression derived by applying the steady‐state oxidation‐reduction model of Mars and van Krevelen to a parallel reaction scheme and assuming first order with respect to both o‐xylene and oxygen:

Significantly, the activation energies for all three postulated reactions with rate constants k1, k2, and k3 turn out to be identical having a value of 14.8 kcal/mole, which may be taken to imply that there is only one rate‐influencing reaction step for all the products and not three as assumed in deriving this equation.
Phase equilibria for the system propane‐ethane‐carbon dioxide
Authors: Hamam Salah E. M. , Lu Benjamin C. Y. 
Published: March 2009

AbstractVapor‐liquid equilibrium data for the ternary system propane‐ethane‐carbon dioxide were determined experimentally at 244.3 and 266.5 K by means of a forced recirculation apparatus. The total pressure investigated varied from 87.5 to 433 psia. The data obtained were compared favourably with the values predicted by means of the Redlich‐Kwong equation of state with a modified procedure. The average absolute deviation between the experimental and calculated P is less than 3% and in y less than 0.0140 mole fraction.
Estimation of standard heats of formation ΔH, standard entropies of formation ΔS, standard free energies of formation ΔF and absolute entropies S of hydrocarbons from group contributions: An accurate approach
Authors: Thinh Tran Phuc , Trong Truong Khac 
Published: March 2009

AbstractA group contribution method for calculation of standard heats of formation ΔH*fT, standard entropies of formation ΔS*fT standard free energies of formation ΔF*fT and absolute entropies S*T, of hydrocarbons is proposed. It is shown that this method is more accurate than any of the ones now appearing in the literature.
Consolidation of sand formation using freon'll gas hydrate
Authors: Cheng W. K. , Pinder K. L. 
Published: March 2009

AbstractFreon 11 gas hydrate was used to block the pores of four size ranges of sand from 24 mesh to 60 mesh. A 50.8 mm deep bed of sand when thus “frozen” with hydrate could sustain a dfferential water pressure of at least 6895 kPa.A subcooling of about 5 to 6°C below its thermodynamic formation temperature was required to cause the hydrate to form such a plug. Once formed, the hydrate remained stable at temperatures up to its decomposition temperature.The time required for the hydrate crystal to grow to a size large enough to block the pores of the bed was about two hours. The amount of hydrate forming agent required to block the sand pores was found to be approximately that calculated from the ideal composition of the hydrate.
Caractéristiques rhéologiques des suspensions de tourbe
Authors: Mejean L. , Boulos M. I. 
Published: March 2009

AbstractL'écoulement des suspensions de tourbe dans l'eau a été étudié sur un domaine de concentrations compris entre 0.75 et 2.25% en poids sec. La granulométrie des fibres était inférieure à 3 mesh.Les pertes de charge ont été mesurées sur une plage étendue de débits, le nombre de Reynolds variant entre 103 et 105, dans trois tubes horizontaux de diamètre interne respectif 50.8, 38.1 et 25.4 mm.Les résultats indiquent que la déviation au comportement newtonien augmente avec la concentration et le diamètre des conduites. La comparaison avec des suspensions diluées de pǎtes à papier révèle que le comportement de ces deux types de suspensions présente les měmes particularités. Les suspensions de fibres sont des fluides non homogènes, et les modèles rhéologiques classiques ne peuvent décrire leur comportement. Le modèle de l'anneau périphérique, qui suppose, en écoulement laminaire, la présence d'un réseau enchevětré de fibres, explique les résultats expérimentaux obtenus.L'analyse granulométrique des particules met en évidence que le type de pompe utilisé a un effet sur la dégradation des fibres.
The coalescence of H2S and CO2 bubbles in water
Authors: Sagert Norman H. , Quinn Michael J. 
Published: March 2009

AbstractCoalescence times are reported for bubbles of H2S and CO2 formed on adjacent nozzles in water. With CO2, times were small (1–3 ms) at pressures below 2 MPa, and rose to 20 ms at 3.4 MPa. With H2S, the logarithm of the coalescence time was proportional to pressure, and coalescence times reached 100 ms at 1.7 MPa. Film stretching rates were calculated assuming that the film surfaces were slightly immobile. By using a form of Vrij's theory for the inherent breaking time of films of constant thickness, the effective number of immobile layers could be calculated. Since these were in the range 10−2 to 10−3, only a small amount of “stiffness” in the film surface is enough to cause large changes in coalescence time.
Effect of heater diameter on the critical heat flux from horizontal cylinders in pool boiling
Authors: Rao P. K. Mohan , Andrews D. G. 
Published: March 2009

AbstractThe characteristic variation of critical heat flux (CHF) with heater diameter in the pool‐boiling of horizontal cylinders is discussed. Critical heat flux expressions have been obtained based on hydrodynamic considerations for saturated pool‐boiling of cylinders and are compared with existing and new data. Experimental studies are reported which verify the postulated mechanics of the boiling process at CHF over a range of cylinder diameters.
Technology and economics of coal gasification
Authors: Papic M. M. 
Published: March 2009

AbstractThe best known commercial coal gasification processes which use oxygen (air) and steam as gasifying media are the gas producer process (normal pressure, fixed bed), Lurgi process (high pressure, fixed bed), Winkler process (normal pressure, fluidized bed) and Koppers‐Tetzek process (normal pressure, entrained). Fixed bed and fluidized bed processes are suitable for gasification of noncaking and weakly caking coals with high ash fusion temperatures (> 1200°C). The entrained system is suitable for gasification of any coal.Low‐caloric gas (∼ 150 Btu/scf) can be produced by the gas producer, Lurgi and Kinkier processes; medium‐ (∼ 300 Btu/scf) and high‐caloric (∼ 950 Btu/scf) gas by any process. Lurgi and Koppers‐Totzek processes are preferred processes for production of synthesis gas at the present time.The costs (/Btu) of production of low‐caloric gas are the lowest followed by the medium‐ and high‐caloric gas costs (see Figure 6). The costs of gas production from coal are mainly dependent on the efficiency of the gasification process, scale of operation and the cost of fuel.