bluuebunny/crossref_metadata_2025_split huggingface dataset:
Exclusion of gas sparger influence on mass transfer in bubble columns
Authors: Deckwer W.‐D. , Hallensleben J. , Popovic M. 
Published: March 2009

AbstractGas phase CO2 concentration profiles were measured in two sizes of bubble columns with different gas spargers and with the liquid phase (tap water) entrance or exit (cocurrent or countercurrent flow) at a certain height above the gas distributor. The region of high turbulence intensity near the sparger was locally separated from the region of high mass transfer rates in such columns. A modified back flow cell model was applied to describe the experimental data. The kL‐values obtained from fitting the profiles agreed for both columns and, in addition, did not differ for cocurrent and countercurrent flow. This is in remarkable contrast to previous findings(10,11). The large influence of the gas sparger on the kL‐values even in tall bubble columns was thus demonstrated. It is thought that this may probably be one of the reasons why correlations for prediction of kL differ so significantly.
Extraction of whole fermentation broth with karr reciprocating plate extraction column
Authors: Karr A. E. , Gebert W. , Wang M. 
Published: March 2009

AbstractThe conventional equipment employed in the pharmaceutical industry for extracting fermentation broths is the centrifugal extractor. However, a recent case history indicates that the Karr Reciprocating Plate Extraction Column should be considered for such applications.A pharmaceutical company had been using a Podbielniak centrifugal extractor to extract a whole fermentation broth. However, they could not feed the broth to the extractor unless they pretreated the broth by a “hand wash” or a preliminary batch extraction. Subsequently, it required three passes through the centrifugal machine to achieve the desired degree of extraction. On the other hand, with one pass through the Karr Column, essentially complete extraction was achieved. The advantages evident included a 55% reduction in solvent requirements, and substantially less capital cost, utilities cost, maintenance cost, and solvent losses.
The application of the characteristic method to shock tube data that simulate a gas pipeline rupture
Authors: Cronje J. S. , Bishnoi P. R. , Svrcek W. Y. 
Published: March 2009

AbstractA numerical procedure is described to solve the equations for single phase, one dimensional, unsteady, compressible, frictional flow with heat transfer. The procedure is based on Hartree's ‘hybrid’ method for solving the governing hyperbolic partial differential equations. Computations for flows in a shock tube are presented which show good agreement with experimental data available for methane and argon.
Spray atomizer droplet spectrum measurement
Authors: Picot J. J. C. , Tomey T. D. , Smedley J. B. , Kristmanson D. D. 
Published: March 2009

AbstractThe gamma function distribution is used to discuss droplet size variation for flat fan and round orifice atomizers. A technique of using multiple‐probe devices to measure droplet size, distribution and flux when the form of the distribution is known is described. Experimental results with a four‐unit conductance probe device are given for a Spraying Systems Tee‐jet operating with a slightly conducting liquid at 4.2 dm3/s and at an air velocity of 75.6 m/s. Probe results give a mass mean diameter of 68 μm while the standard photographie method gives 78 μm. A material balance using probe results gives a liquid flow of 6.0 dm3/s. The accuracy of this method is easily improved by adding more units, but the restrictions of conducting liquid and the mechanical problems of probe construction and calibration indicate that optical probes should be investigated.
Surface area prediction for two phase drops in an immiscible liquid
Authors: Pinder K. L. 
Published: March 2009

AbstractThe three interfacial areas of a liquid drop evaporating in an immiscible continuous liquid have been measured from three‐dimensional still photographs. Five dispersed phases in water have been used.From empirical correlations for the vapour bubble open angle and eccentricity with the physical parameters of the system, the initial drop diameter and the vapour ratio, the three interfacial areas may be predicted. The maximum error in the predictions were found to be ±5.2% for the liquid‐liquid area, ± 17.1% for the vapour cap area and ±15% for the internal vapour‐liquid area for drops of initial diameters less than 0.4 cm.
Aerodynamics of a vibrated fluid bed
Authors: Gupta Rahul , Mujumdar A. S. 
Published: March 2009

AbstractResults of an experimental study on the aerodynamics of a vertically vibrated fluidized bed of cross‐section 0.2 × 0.2 m are presented and discussed. Variables studied included frequency (0‐105 s−1), amplitude (0‐5xl0−3 m), bed height (12.5‐100×10−3 m), particle size (900‐3900 μm), particle density (570‐890 kgm−3), particle shape factor (0.55‐1.00) and the particle surface characteristics, i.e. presence of surface moisture.The effect of vibrational parameters on the fluidized bed pressure drop, the newly defined minimum mixing velocity, Umm and overall aerodynamic behaviour of the bed is discussed on the basis of quantitative as well as visual observations. Empirical correlations are proposed for δPmf and Umm, which were both found to decrease significantly with increase in the vibrational acceleration.
Effect of swirl and confinement on the flow and temperature fields in an inductively coupled r.f. plasma
Authors: Boulos Maher I. , Gagne Ronald , Barnes Ramon M. 
Published: March 2009

AbstractA mathematical model was used for the calculation of the flow and temperature fields in the fire‐ball of an inductively coupled plasma (ICP) under confined and free discharge conditions taking into account gravity and swirl in the sheath gas. Computations were made for an argon plasma at atmospheric pressure operating at a power level of 3kW and a frequnecy of 3 MHz. Natural convection has a negligible effect on the flow and temperature fields under confined discharge conditions, but a significant effect, for the free plasma discharge. The back flow in the discharge was substantially reduced in the presence of swirl for swirl velocities over the range 0‐70 m/s. With a moderate increase in swirl, the conduction heat flux to the wall decreased but increased with the further increase in swirl.
Second‐law efficiency analysis of a coal gasification process
Authors: Rodriguez S. J. Luis , Gaggioli Richard A. 
Published: March 2009

AbstractThe present paper summarizes a comprehensive Second‐Law analysis of the SYNTHANE process of coal gasification(1), based on the available‐energy concept as applied to design conditions and data.The analysis yields an overall process efficiency of 46%. For every 100 MJ of useful energy supplied with coal, 51 MJ are consumed during the various unit operations while effluents carry 3 MJ. Unit 30, Steam and Power Production, consumes nearly 20 MJ; Unit 15, Gasification, used up nearly 16 MJ; Units 12 and 14, Coal Preparation and Feeding, about 5 MJ; Units 16 and 17, Raw Gas Quenching and Shift Conversion, 4 MJ; Unit 32, Oxygen Plant, approximately 2 MJ; other miscellaneous units contribute a combined available‐energy destruction of 4 MJ.The Second‐Law analysis unveils the inefficiencies present in the process and their sources, thus pinpointing the opportunities for improvement in the SYNTHANE process.
Model reduction of high‐order multistage systems by the method of orthogonal collocation
Authors: Wong Kin Tuck , Luus Rein 
Published: March 2009

AbstractA straightforward model reduction procedure is developed for high‐order multistage systems. It is proposed to generate a partial differential equation from the original system and then to use the orthogonal collocation procedure to establish a low‐order reduced model. This low‐order model can then be used for time‐optimal control with the assurance that the optimal control, as determined for the reduced system, can be applied to the original system. The procedure is illustrated with a 20‐plate gas absorber which is eventually reduced to 5 state equations.
Evaporation under an impinging jet: A numerical model
Authors: Mujumdar A. S. , Li Y.‐K. , Douglas W. J. M. 
Published: March 2009

AbstractA numerical model is presented to predict the flow and coupled heat and mass transfer characteristics under a round laminar jet impinging normally on a plane wall maintained at a constant wet‐bulb temperature. The full Navier‐Stokes energy and conservation of species equations in their primitive form are solved using a finite difference technique for the case of a jet of hot humid air impinging on an isothermal wet surface. It is found that a modified Sherwood number defined in terms of a log‐mean, mole fraction driving potential renders the former insensitive to the evaporation rate.
Bulk and interfacial physical properties of aqueous solutions of sodium lauryl sulphate: Part IV: Dilute aqueous solution behavior by electron spin resonance studies and by pH and surface tension measurements
Authors: Vijayan S. , Ramachandran C. , Woods D. R. 
Published: March 2009

AbstractThe electron spin resonance spectrum of the nitroxide label 2,2,6,6 – TetraMethyl – 4 – Piperidone – Oxide (TEMPO) has been investigated in aqueous solutions of a purified and commercially available impure samples of sodium lauryl sulphate (NaLS) for a wide range of concentrations. The spectra were recorded at 24°C as a function of surfactant concentration. The reorientational correlation times Tθ of the TEMPO label in aqueous solutions were calculated using the Kivelson's theory. Using the Tθ data qualitative analysis has been carried out in an attempt to understand the microscopic effects produced by the hydrophobic part of the surfactant on the water structure and the hydrophobic‐hydrophobic interactions in water.Four major discontinuities in the τθ results have been identified with the purified NaLS system. They are found to occur at NaLS concentrations of 0.008 wt.%, 0.015 wt.%, 0.23 and 1.73 wt.%. The latter two concentrations represent the first and the second critical micelle concentration (CMC) of the surfactant while the first two concentrations reveal the existence of premicellar association and dissociation processes, respectively. These discontinuities have been also confirmed by the pH data and by surface tension results from the du Noüy ring method.The effect of addition of lauryl alcohol and sodium chloride on τθ values was also studied. The additive action has been found to produce an additional discontinuity, corresponding to the mixture CMC, in the τθ versus concentration plot. Analysis of other effects such as solution aging and hydrolysis of NaLS are also included.The applicability of the spin labelling technique for the study of aqueous solution behavior of NaLS is discussed by comparing data reported in the literature.
Kinetic investigation of complex pseudo mass action systems by use of the pulse method
Authors: Christoffel Erhard G. , Surjo Indarto T. , Robschlager Karl‐H. 
Published: March 2009

AbstractWith simultaneous isomerization and cracking of the five hexane isomers on a bifunctional Pt/Al2 O3‐catalyst as a model reaction, which has been shown to follow pseudo mass action kinetics, it is demonstrated how the microcatalytic pulse technique can be applied for the kinetic analysis of complex linear reaction networks. From the experimental data relative rate constants for the individual reaction steps have been obtained by use of the Wei‐Prater‐method. The results are compared with results from continuous operation.
Kinetic investigation of the isomerization of C8‐aromatics
Authors: Röbschäger Karl‐H. , Christoffel Erhard G. 
Published: March 2009

AbstractThe kinetics of isomerization of C8‐aromatics on a bifunctional Pt/zeolite catalyst has been studied at 422°C, total pressures of 7.102 KPa to 18.102 KPa and H2/hydrocarbon ratios of 3 to 18 in a fixed bed reactor. The rate of ethyl‐benzene isomerization can be described on the basis of a bifunctional reaction mechanism. For modeling the rates of interconversion of the C8‐aromatics linear rate laws are suitable as long as hydrogen and hydrocarbon partial pressures are kept constant.
Bitumen separation for experimental use
Authors: Vorndran L. D. L. , Serres A. J. , Donnelly J.K. , Moore R. G. , Bennion D. W. 
Published: March 2009

AbstractA solvent extraction procedure is presented for separating large quantities of bitumen to be used in laboratory experiments. The effectiveness of various solvents is discussed. Data are presented on the properties of extracted bitumen, the unextracted residue and the light ends lost during solvent removal. The effect of bitumen contact with oxygen is also discussed.
Kinetics of oxidation of cuprous chloride by oxygen in aqueous hydrochloric acid solutions
Authors: Hikita H. , Ishikawa H. , Matsuda M. 
Published: March 2009

AbstractThe rates of absorption of oxygen into aqueous cuprous chloride solutions containing hydrochloric acid were measured at 15, 25 and 35°C using a baffled agitated vessel operated batchwise and the experimental results were analyzed with the chemical absorption theory.The reaction between oxygen and cuprous chloride was found to be second order, i.e. first order with respect to oxygen and CuCl2− ion which is the actual reactive species in aqueous cuprous chloride solutions containing hydrochloric acid. The reaction rate constants were calculated and correlated as a function of temperature.
A fluidized bed retort for oil sands
Authors: Donnelly J. K. , Moore R. G. , Bennion D. W. , Trenkwalder A. E. 
Published: March 2009

AbstractFluid bed retorting of oil sands is a viable method of extracting oil from mined oil sands. The process is based on a direct heating concept in which one vessel is utilized for the pyrolysis and vaporization of the bitumen contained in the oil sand and for the burning of the residuals which remain with the sand.Experimental results show that a significantly upgraded liquid hydrocarbon product can be obtained. Oil yields can exceed eighty per cent of the bitumen present in the feed material. The sulfur content of the produced oil is reduced. Gas produced can have a significant heating value and contains sulfur mainly in the form of hydrogen sulfide. Refluxing of the overhead product increases liquid yields and reduces the sulfur content of the oil. Water injection and the use of enriched air has a beneficial effect on the process. Thermal efficiencies in excess of eighty per cent can be achieved without recovering the heat from the expended sand.
Vapor‐liquid equilibria for the ternary system n‐Heptane/n‐Propanol/l, chlorobutane and its constituent binaries at 318.15 and 338.15 K
Authors: Ashraf F. A. , Vera J. H. 
Published: March 2009

AbstractIsothermal liquid‐phase composition — total pressure, x‐P, data were measured for the ternary system n‐heptane/n‐propanol/l, chlorobutane and its constituent binaries at 318.1 S and 338.15 K. A total pressure static equilibrium apparatus was used. The binary x‐F data were correlated using four semi‐empirical local‐composition expressions for the activity coefficients, i.e. the Wilson, the LSG, the LCG and the UNIQUAC equations. The performance of these equations to predict the ternary data has been compared. In general, all four equations were found to give good predictions. The best results were obtained with the Wilson and the LCG equations.
Finite difference simulation of die swell for a newtonian fluid
Authors: Hill G. A. , Shook C. A. , Esmail M. N. 
Published: March 2009

AbstractThe phenomenon of die swell for Newtonian fluids has been successfully simulated using a finite difference numerical method. The calculations predict the surface shape of Newtonian jets over a range of Reynolds numbers from 4.2 to 92.3 for both rectangular slits and cylindrical tubes. The calculated die swells for tubes compare favourably to experimental data. Velocity profiles and pressure distributions in jets exiting from slits or tubes are also predicted. The numerical data were incorporated into a momentum balance expression to demonstrate factors influencing this phenomenon. Other solutions were calculated to predict the effect of gravity and a sudden perturbation in flow on the resulting jet shape.
The application of robust and non‐interacting control schemes to a heat‐exchanger stirred tank process
Authors: Taylor P. A. , Wright J. D. , Tu T. 
Published: March 2009

AbstractAn experimental study involving the digital computer implementation of four multivariable control schemes to a heat‐exchanger stirred process has been performed. The control schemes varied in their complexity and in the amount of process information required for their design. The analysis of the experimental data shows how each controller handled the asymmetric non‐linearity and dead times inherent in the process. The development of the theory shows why the best control was not always achieved with the most sophisticated controller. The controllers are suitable for industrial applications.
Electrochemical simulation of heat and mass transfer in agrometeorology
Authors: Schuepp P. H. 
Published: March 2009

AbstractDiffusion and convection controlled electrode reactions have been used to study a wide variety of agricultural heat and mass transfer problems. The paper reviews applications to the heat and mass transfer of plants in free and forced convection, the role of electrochemical simulation on the development of predictive models for soil‐atmosphere and soilcrop transfer and investigations of transfer in intermittent flow.Where field data are available they tend to confirm the validity of the technique. The biggest deficiency, noticeable particularly in intermittent flow around turbulence‐producing obstacles (vegetation, barriers), appears to be the fact that presently‐used models cannot deal adequately with two – and three – dimensional flow and sporadic boundary‐layer penetrations by irregular ‘events’. Electrochemiluminescent flow visualization may help in developing better qualitative and quantitative descriptions of such flows.
The flow of rarefied gases through long tubes of circular cross‐section
Authors: Datta Ravindra , Rinker Robert G. 
Published: March 2009

AbstractA brief review is presented of various models of rarefied gas flow in long tubes. The complex treatments based on the Boltzmann equation provide only numerical solutions for the transition region unless some arbitrary assumptions are made, while those based on the traditional approach of simple kinetic theory have usually involved empiricism to a greater or lesser extent. An analytic expression is derived here based on a physically realistic model, making use of simple kinetic theory and containing no arbitrary assumptions. The model is completely predictive and adequately describes the flow in long tubes over the entire pressure range, from free‐molecule to continuum laminar flow, and also predicts the “Knudsen minimum” in the transition region. The concept of a “geometric mean free path” is introduced and appears to be useful in analyzing rarefied gas dynamics in a confined space. A relation is also obtained for the viscosity coefficient in the transition region.
Entrainment of particles from a pilot scale fluidized bed
Authors: George S. E. , Grace J. R. 
Published: March 2009

AbstractParticles entrained from a pilot scale fluidized bed of sand having a mean size of 102 μm have been captured and analysed at superficial air velocities up to 1.3 m/s. Variation of bed temperature over the range 300 to 445 K and insertion of a tube bundle in the splash zone had little effect on the measured entrainment fluxes. Existing correlations for predicting entrainment from fluidized beds gave widely divergent results, and generally differed markedly from the experimental data. Of the correlations tested, the graphical saturation carrying‐capacity correlation of Zenz and Weil gave the best agreement with the experimental data. The size distribution of particles carried over differed widely from the size distribution in the bed at low gas velocities but approached the in‐bed distribution at higher velocities.
Concentration distributions in laminar pipe flow with distorted velocity profiles
Authors: Jain S. C. , Chen B. H. 
Published: March 2009

AbstractA laminar flow field in which the velocity profile may be distorted in a predictable manner was achieved in a 7‐cm porous pipe with uniform wall injection over the ranges of variables: 0≤ λ ≤ 2, 200 ≤ NRe ≤ 800 and 0.05 ≤ X ≤ 0.2.A mathematical model was then developed to describe the concentration distribution of a gaseous tracer discharged continuously from a finite source in this particular flow field. Experimental measurements taken over the same ranges of variables verified the validity of this model. The result from this study may be useful in the water desalination process using reverse osmosis.
Gas absorption at a liquid surface agitated by vortex rings
Authors: Rohatgi A. , Baird M.H.I. 
Published: March 2009

AbstractUnderwater vortex rings have been formed at orifices of between 25.4 and 63.5 mm diameter and projected upwards at the surface of the water. The conditions of ring formation at which significant surface deformation occurs have been correlated. The absorption of pure carbon dioxide by the water surface with impinging vortex rings has been measured and related to the following variables: time of fluid impulse through the orifice, orifice diameter, volume of displaced liquid, and depth of submergence. A simplified mass transfer model based on the penetration theory approximately correlates the data.
The effect of saline concentration on the viscous properties of lignite water suspensions
Authors: Darby Ron , Mallett Mark W. 
Published: March 2009

AbstractThe influence of saline in small concentrations on the rheological behavior of concentrated suspensions of lignite in water was determined. It was found that for solids volume fractions below about 40%, the suspension viscosity exhibited a slight minimum at a saline concentration of about 1 mmol/L whereas the viscosity exhibited a maximum at this same saline concentration for solids volume fractions above about 40%. An explanation is offered in terms of the electrostatic effects of adsorbed ions and crowding effects.
Dynamic simulation of multicomponent distillation
Authors: Morris C. G. , Svrcek W. Y. 
Published: March 2009

AbstractA program has been developed for the dynamic simulation of large scale chemical processes. The simulator has a highly modular structure and an explicit integration routine which is capable of handling large systems of stiff ordinary differential equations. The use of an explicit method reduces computer storage requirements and greatly simplifies the writing of new modules.Unit subroutines have been written which are capable of describing multicomponent distillation columns without resorting to conventional thermodynamic equilibrium calculations. The absence of these iterative routines reduces computation time and allows tray efficiencies to be handled in a more natural manner than is possible with Murphee efficiencies. The program also includes an advanced thermodynamic property package based on the Peng Robinson equation of state.An industrial process consisting of two distillation columns with a combined total of seventy‐five mass transfer stages, has been successfully simulated and the computed results have been compared with dynamic data collected from plant tests.