bluuebunny/crossref_metadata_2025_split huggingface dataset:
The multicomponent solubility of hydrocarbons in water
Authors: Leinonen Paul J. , Mackay Donald 
Published: March 2009

AbstractThe aqueous solubility of six binary hydrocarbon systems consisting of benzene and cyclohexane with each of 2‐methyl‐pentane, n‐hexane, and l‐hexene, have been measured at 25d'C. The solubility of each hydrocarbon component is greater by from 6 to 35% than the value expected by prediction on the basis of the solubility of the hydrocarbon component being proportional to its mole fraction in the hydrocarbon phase. This positive deviation is partly attributable to the activity coefficient of the hydrocarbon in the hydrocarbon phase being slightly greater than unity. There is, however, additional solubility enhancement of from 1 to 25% with an average of 10.7% apparently due to the reduction of the hydrocarbon activity coefficients in the aqueous phase by the presence of the other hydrocarbon. The implications of these effects in calculating the solubility of complex hydrocarbon mixtures in water is considered.
Production of mono‐dispersed drops by forced vibration of a liquid jet
Authors: Rajagopalan R. , Tien Chi 
Published: March 2009

AbstractThe production of mono‐dispersed liquid drops by controlled vibration of a liquid jet issuing from a capillary has been investigated experimentally. The variables studied are the physical properties of the liquid, the dimensions of the capillary and the frequency and amplitude of the vibration. Stainless steel hypodermic needles of various sizes (22G to 30G) were used as capillary and the test liquids were water, aqueous solutions of human serum albumin (HSA) and aqueous solutions of glycerol. The experimental results reveal conditions under which drops of good mono‐dispersity can be produced.
Permeation of hydrocarbon gases through polymer membranes
Authors: Chung T. S. , Howell J. A. 
Published: March 2009

AbstractExperimental results are presented for the permeation of propane and ethylene through polyethylene membranes and for the permeation of propane through “Saran” in the temperature range from —10 to 20°C and the pressure range from 20.0 to 50.0 psig. The flux of propane through polyethylene exhibits a minimum as the temperature approaches the condensation temperature. No such minimum was observed either for the flux of ethylene through polyethylene or for propane through “Saran”.The permeability coefficients for propane through polyethylene are compared with those predicted on the assumption of a diffusion coefficient exponentially dependent on the concentration of permeability.
Measurement of residence times, and film and drop velocities in two phase annular flow
Authors: Jagota A. K. , Rhodes E. , Scott D. S. 
Published: March 2009

AbstractThe development of tracer pulse techniques for measuring mean film and droplet velocities (film and droplet residence times) in vertical two phase annular flow is described. Results of experiments are discussed, and compared to a computer simulation of a tracer pulse in annular flow as described by the interchange model. The experiments show that the mean film velocity can be determined accurately, but not the droplet velocity. The computer simulation supports the experimental results. The effect of interchange is also shown to be sufficiently large in much of the annular flow region to give average film and droplet residence times which are not greatly different.
Solids entrainment in a large gas fluidized bed
Authors: Fournol A. B. , Bergougnou M. A. , Baker C. G. J. 
Published: March 2009

AbstractEntrainment from a gas fluidized bed of cracking catalyst in a 2‐ft diameter column equipped with continuous solids recycle has been studied. Radial profiles of entrainment rate and mean particle size were relatively flat. The entrainment rate decreased rapidly with increasing height above the bed and with decreasing fluidizing velocity. The existence of a transport disengaging height above which the entrainment rate and mean particle size become essentially constant was confirmed experimentally. This may be taken as the height above the bed surface at which the inverse Froude number becomes equal to 1000.
Friction reduction by chemical additives in the turbulent flow of fibre suspensions
Authors: Bilgen E. , Boulos R. 
Published: March 2009

AbstractThe effect of friction reducing additives on the turbulent flow characteristics of fibre suspensions have been studied experimentally by using a small diameter straight tube and a free rotating disk. The fibre concentration varied between 0.1 and 5.0%. The friction reducing additives were polyethylene oxide and guar gum. The optimum conditions for friction reduction and effects of temperature, aging and mechanical degradation have been determined; the viscoelastic behaviour of fibre suspensions with and without additives have also been studied. It is shown that the use of friction reducing additives in the turbulent flow of paper making fibre suspensions results in a friction reduction comparable to that in water and the quality of fibre suspensions can be improved.
Oxidation of propane over a diesel exhaust catalyst
Authors: Wanke Sieghard E. 
Published: March 2009

AbstractThe oxidation of propane, over a concentration range of 0.30 to 1.04 mole % in air was investigated over a commercial diesel exhaust catalyst consisting of CuO, Cr2O3and Pd supported on Al2O3. The rate of reaction was correlated by a first order, irreversible rate function; the resulting pre‐exponential factor and activation energy were 3.15 × 107cc/g‐sec and 21.3 kcal/gmole, respectively. At high temperatures the reaction rate became influenced by pore diffusion. A temperature of 675°K was required to obtain 50% propane conversion. It was concluded that this catayst is unsuitable for catalytic mufflers on diesel buses since the measured value of diesel exhaust temperatures at the cataytic muffler inlet is significantly less than 675°K.
Identification of a packed absorption column
Authors: Malpani S. N. , Donnelly J. K. 
Published: March 2009

AbstractA method is presented for the identification of parameters in the partial differential equations describing the dynamic behaviour of a certain class of two phase flow processes. This method is an extension of a procedure for the identification of single phase flow processes which were introduced in a previous paper. The method is applied to the identification of two parameters in the five simultaneous partial differential equations describing the behaviour of a packed absorption column being used to remove carbon dioxide from air with an aqueous solution of monoethanolamine. These parameters were determined from a single experimental step response. The approach employed was to reduce the partial differential equations to two coupled systems of ordinary differential equations by the method of characteristics. Once in this form the identification problem could be formulated as two coupled boundary value problems and solved with the use of quasilinearization.
The optimization of serial processing systems
Authors: Bundgaard‐Nielsen M. , Rono P. E. 
Published: March 2009

AbstractThe literature on applications of dynamic programming in the chemical processing industries is quite comprehensive. However, only a few studies have been conducted in which the strategy of dynamic programming has been compared with efficient optimization algorithms not utilizing the structural properties of the optimization problem in question. The purpose of this short note is to report on the results of such a comparative study and to suggest some general guidelines as to the proper choice of optimization strategy when dealing with serial processing systems in the chemical industry.
Drag coefficients and pressure drops for hydrodynamically suspended spheres in a vertical tube with and without polymer addition
Authors: Latto B. , Round G. F. , Anzenavs R. 
Published: March 2009

AbstractThe pressure drops associated with the suspension velocities for single, hydrodynamically suspended spheres were measured for a range of steel spheres in a 5.3 cm diameter vertical glass tube. Nineteen different sphere to tube diameter ratios (d/D) were investigated ranging from 0.191 to 0.967. Three different liquid media were used: pure water, and two polyacrylamide solutions of concentration 25 wppm and 50 wppm of Reten 423.In the range 0 < (d/D) < 0.7 polymer addition increased the drag coefficient. For d/D > 0.7 the drag coefficient was not affected. The available data for air, water and polymer solution were correlated with an equation explicit in pressure drop, and the agreement between theory and experiment was found to be excellent.
Exact solutions for a class of heat and mass transfer problems
Authors: Davis E. James 
Published: March 2009

AbstractA number of heat and mass transfer problems of chemical engineering interest involve the convective diffusion equation of the form

where θ = θ(X1, X2). Exact solutions for such problems are developed in terms of well‐known functions which have been thoroughly studied in recent years. Several problems which have appeared in the literature, solved by completely numerical methods, are re‐examined and new problems are discussed and solved. The results of the present analysis are compared with those obtained by other methods where possible. The problem of axial diffusion of heat or mass is solved in terms of known functions.The present formulation is shown to be particularly useful in the analysis of conjugated boundary value problems, i. e. for problems involving heat or mass transfer across an interface where the interfacial boundary condition is not known a priori but is related to the temperature or concentration fields in the adjacent phases.
Interpretation of experimental rates of reaction for multiple step chemical reaction systems: Part I: A general modelling procedure
Authors: Lana I. G. Dalla , Myint A. , Wanke S. E. 
Published: March 2009

AbstractExperimental kinetic data in a form equivalent to concentration‐time trajectories (or the corresponding rates of reaction) may be decomposed into rate data for the individual chemical reaction steps defining a chemical reaction network. When kinetic models are fitted to each set of single‐step rate data, the resulting single‐step kinetic models may be combined to formulate an overall kinetic model for the network. Such network‐kinetic models may exhibit consistency with both the apparent chemistry and the observed rate behaviour.
Symposium on application of pulse techniques to kinetic measurements: Étude d'une réaction homogène rapide d'ordre deux en phase gazeuse par des méthodes transitoires dans un réacteur autoagité
Authors: David Et Rene , Villermaux Jacques 
Published: March 2009

AbstractThe determination of the kinetics of butadiene dimerization, a second‐order rapid and homogeneous reaction, could be determined in a continuous reactor which was thoroughly stirred in a gas phase by jets from nozzles. The above reaction was studied between 500°C and 600°C by means of a transient method based on the deformation of a concentration pulse signal while crossing the reactor.A study was also made of a modification of the transient method which consisted in superimposing a small pulse to a continuous feed of reactant. The linearization permitted to bring the reaction back to an apparent first order one with respect to the butadiene concentration.The concentration signals were measured by means of a mass spectrometer and stocked in actual time on an IBM 1800 computer.The results found in both cases agreed well with those described in the literature and with those of the conventional method in a steady system.The following expression of the kinetics constant was obtained.
Thermal instability of laminar natural convection flow on inclined isothermal plates
Authors: Hwang G. J. , Cheng K. C. 
Published: March 2009

AbstractAn analysis is made to deteimine the conditions marking the onset of longitudinal vortices in the laminar natural convection flow over a heated isothermal inclined plate. A linear stability theory based on Boussinesq approximation and without the conventional parallel‐flow assumption for basic velocity and temperature profiles is employed in the derivation of perturbation equations. An iterative procedure employing a fourth order Runge‐Kutta method is applied in the solution of the perturbation equations. A comparison between the neutral stability resuts obtained with and without the commonly used parallel‐flow approximation in the stability theory of small disturbances shows that the parallel‐flow assumption is an invalid one for the present problem. Solutions are obtained for Pr = 0.72, 1, 2, 10, 100, and ∞ and the critical Rayleigh number marking the onset of longitudinal vortices is found to be a rather weak function of Prandtl number. A comparison of the present neutral stability results for the inclination angles α = 20° ∼ 60° with experimental data reported in the literature reveals that the theory predicts critical values which are generally two orders of magnitude lower than the experimental data.
Hydrogen sulphide — air equilibria under claus furnace conditions
Authors: Bennett H. A. , Meisen A. 
Published: March 2009

AbstractEquilibrium compositions of mixtures resulting from reactions between hydrogen sulphide and air at atmospheric pressure were calculated for temperatures and O2/H2S ratios ranging from 600 to 2000°K and 0.05 to 1.0, respectively. Forty‐four compounds containing nitrogen, hydrogen, oxygen and sulphur were assumed to be formed but only 25 had concentrations exceeding 0.1 ppm. These compounds should not, as in previous studies, be omitted from equilibrium calculations. Sulphur yields are shown to be increased by approximately 10% if O2/H2S ratios less than stoichiometric are used. Reasons for this and implications for Claus plant operation are provided.
Oxidation of propionic acid solutions
Authors: Day D. C. , Hudgins R. R. , Silveston P. L. 
Published: March 2009

AbstractWet air oxidation is a process in which organic materials in the aqueous phase are oxidized by air at temperatures between 300°F and 600°F and pressures of 1000‐1800 psia. To improve our understanding of the process, its kinetics were studied using a propionic acid solution to simplify both analysis and rate measurements. The aim of the research was to define the regime where the reaction rate is kinetically controlled, to develop a model for the reaction rate and to interpret the model in terms of mechanism. Oxidation appears to proceed homogeneously in the aqueous phase and is probably kinetically controlled between 450° and 550°F. The oxidation appears to take place via two principal routes. Approximately half the propionic acid is oxidized completely to carbon dioxide while the oxidation of the remainder apparently proceeds via acetaldehyde as an intermediate to acetic acid. Acetic acid oxidizes only at a very low rate. A power law rate expression was developed which adequately described the oxidation of propionic acid solutions.
The screening and selection of solvents for the extraction of phenol from water
Authors: Kiezyk Peter R. , Mackay Donald 
Published: March 2009

AbstractThe thermodynamic basis foi the selection of solvents for the removal of phenol by liquid‐liquid extraction from waste water is discussed. Data are presented showing the often marked dependence of distribution coefficient on solute concentration at levels of 5 to 1000 mg/l. Experimental and literature data for the infinite dilution activity coefficient of phenol in 26 solvents at 25°C are correlated using a Regular Solution approach by assigning a value to an interaction energy term dependent on the chemical nature of the solvent. The accuracy is not sufficient for design purposes but the method can be used for screening. Toxicity and biodegradability of the preferred solvents are discussed.
Coalescence of drops in a liquid‐liquid dispersion by passage through a fibrous bed
Authors: Rosenfeld J. I. , Wasan D. T. 
Published: March 2009

AbstractA model which describes the operation of a fibrous bed coalescer is presented. From this model, a theoretical equation can be derived for the filter coefficient, λ, at small velocities where the effect of turbulence is negligible. This expression which considers the void fraction of the bed, ϵ, the drop diameter, dp, the average saturation, Sm, the fiber diameter, dP, and the effective fiber diameter dfe, is:where β is the fraction of collisions which lead to coalescence. At larger velocities, a suitable empirical equation is obtained by multiplying the above expression by the square root of the velocity at which the filter coefficient begins to decrease divided by the superficial velocity. These equations describe the data of various workers.A method of obtaining the average saturation in a fibrous bed is presented. A possible correlating equation is found to be:where U is the superficial velocity.
Vertical two‐phase flow part I. Flow pattern correlations
Authors: Oshinowo Toks , Charles M. E. 
Published: March 2009

AbstractTwo‐phase gas‐liquid flow has been investigated in a 1‐inch internal diameter vertical tube coil containing two risers and a downcomer all connected by “U” bends. Flow pattern data were obtained in the three vertical tubes, each 17.30 ft. long, for five different air‐liquid systems at about 25 psia over flow ranges of 0–700 lbmair/min‐ft2and 140–25300 lbmliquid/min‐ft2. Liquid phase viscosities ranged from 1 to 12 cp.A flow pattern classification with six regimes including coring‐bubble, bubbly‐slug, falling film, falling bubbly‐film, froth and annular flow regimes was established for downflow. Flow patterns in the bends were also classified.Data from the present investigation were used to formulate an empirical flow pattern graphical correlation for both upflow and downflow which is based upon the coordinates (Rv)1/2and FrTP/A, where Rvis the delivered gas‐to‐liquid volume ratio, FrTPis the mixture Froude number, and A = μs/(SLσs3)1/4in which μs, SL, σsare specific viscosity, specific density and specific surface tension respectively of the liquid with reference to water. The correlation was satisfactorily tested with independent literature data for upflow systems, including air‐water, steam‐water at various pressures, nitrogen‐mercury and air‐heptane, and data from flowing gas‐oil wells. No independent literature data appear to be available for testing the correlation for downflow systems, but it is anticipated that the correlation will prove to be generally applicable.The coring phenomenon in downward bubble flow was examined by means of high speed motion photography and is explained by the development of a lift force on a bubble.
The effect of mass transfer on flow characteristics in vertical two‐phase unstable flow
Authors: Golding J. A. , Mah C. C. 
Published: March 2009

AbstractStudies carried out on the absorption of hexane from inert carrier gases into paraffin oil have shown that mass transfer can affect flow characteristics in unstable vertical two‐phase flow. In the absence of mass transfer chain‐flow patterns prevailed. These patterns were broken when mass transfer took place from the gas to the liquid phase. Bullet shaped slugs were then formed, the slugs pairing and coalescing as they rose up the column. The direction of mass transfer was critical no effect on flow pattern being observed when mass transfer took place from the liquid to the gas phase.Slug frequencies and slug sizes were found to be influenced by mass transfer and an effect of overall absorber length was observed. Individual slug sizes and separation distances were measured and varied widely even under constant flow conditions. Rise velocities were correlated using an equation of the form:where C2 was a function of the fluid flow‐rates and system physical‐properties.
Developments in spouted bed technology
Authors: Mathur Kishan B. , Epstein Norman 
Published: March 2009

AbstractThe spouted bed, though originally developed for drying of coarse granular solids, has, over the last decade, proved to be of interest for carrying out a remarkably wide variety of operations. These include not only other diffusional and/or thermal operations such as heating or cooling of solids, drying of solutions and suspensions onto inert bed particles, particle coating, and granulation, but also certain mechanical functions like solids blending, comminution and aerosol collection from a gas stream. The use of spouted bed reactors for several chemical processes — coal carbonization, shale pyrolysis, ore roasting, cement clinker production, and thermal cracking of petroleum — has also received attention.This paper presents a review of the above developments, supplemented in a few cases by recent results of research being carried out at the University of British Columbia. The particular features of a spouted bed which play the key role in each type of application are identified, some new applications are suggested and consideration given to the future industrial potential of individual processes.
Residence time distribution of gas in spouted beds
Authors: Lim C. J. , Mathur Kishan B. 
Published: March 2009

AbstractStimulus‐response experiments have been carried out, using helium gas as tracer, to measure the residence time distribution of gas in spouted beds. The data obtained, under a variety of experimental conditions, are compared against predictions from a two‐region gas flow model. The model postulates plug flow of gas in the spout and axially‐dispersed plug‐flow in the annulus, the extent of axial dispersion being accounted for by a coefficient, D, which is an adjustable parameter of the model. The values of D thus determined were found to increase with gas flow rate, to be relatively insensitive to bed path, and to be much larger for beds of wheat than of polystyrene.
The application of soil mechanics to spouted bed design
Authors: McNab G. S. , Bridgwater J. 
Published: March 2009

AbstractThe annular material around a spout may be considered to be a loosely packed assembly of particles with its behavior described by effective stresses using the Mohr‐Coulomb failure criterion as employed in soil mechanics. The work shows the development of a height‐independent stress model together with an interpretation of the mathematical results in physical terms. The form of a simple equation for spout diameter is shown which gives some information about the interactions between the spout and the annular material.
Minimum air requirement for spouting mixed particles
Authors: Brunello Giovanni , Nina Gilberto Della , Nunes Francisco Carlos S. , Nascimento Claudio Augusto O. 
Published: March 2009

AbstractMinimum spouting velocity data for beds of soybean (dp = 0.246 in.) and sorghum (dp = 0.142 in.) mixtures contained in a 12 in. diameter column are reported. The agreement of some of the existing correlations is tested against these data, and an empirical equation for this particular case is proposed.
Pressure and flow characteristics of a gas phase spout‐fluid bed and the minimum spout‐fluid condition
Authors: Nagarkatti A. , Chatterjee Asok 
Published: March 2009

AbstractSpoutfluidization is a new technique for solid‐fluid contact which aims at incorporating the advantages of spouted bed and fluidized bed technique.The characteristics of physical state of the bed with the variation of the variables which include flow of fluid, particle diameter, orifice diameter, bed height, are studied in this investigation. Experimental study of minimum spoutfluidizing velocity using glass beads with mean particle diameters from 0.254 to 0.600 mm has been carried out in a 90 mm glass column with three spouting inlet orifice sizes at different bed heights. Phase diagrams indicate that the minimum spout‐fluid flow rate in a gas‐solid system may be a point property for a given bed. A correlation is presented in which the standard deviation of experimental from calculated minimum spoutfluidizing velocity is within 5%.