bluuebunny/crossref_metadata_2025 huggingface dataset:
Rate models for cyclic separation processes — comparison with experimental results in cyclic electrodialysis
Authors: Thompson D. W. , Bass D. , Abu‐Goukh M. E.
Published: March 2009

Two rate models for cyclic separation processes are discussed in terms of their applicability to cyclic electrodialysis. Both the constant‐rate model and the concentration‐dependent‐rate model predict little or no separation when the fluid displacement cycle is continuous and in phase with a continuous electric current cycle. Modification of the cycles by periodically interrupting either the electric current or the fluid flow, or by out‐of‐phase operation, leads to large separation. These observations are shown to be in agreement with previously published experimental results.
Liquid‐liquid separations in a conventional hydrocyclone
Authors: Sheng H. P. , Welker J. R. , Sliepcevich C. M.
Published: March 2009

The performance of a conventional hydrocyclone for separation of immiscible liquids was investigated experimentally. The results are particularly useful for evaluation of multi‐cyclone process design of same system. The effect of materials of constructions of the hydrocyclone on the separation efficiency was also tested. Significant differences in performance were noted depending on the preferential wettability characteristics of the solid surfaces for the liquids being separated.
Rate constants of elementary steps by pulse technique
Authors: Hattori Tadashi , Murakami Yuichi
Published: March 2009

Two methods for measuring the rate constants of the elementary steps by the pulse technique are proposed. The first gives the adsorption and the desorption rate constants from the retention time and the half width of the chromatographic peak, and was applied to the adsorption of benzene on HY and CaY zeolites. The second gives the surface reaction rate constant and the desorption rate constant of the reactant from the peak of the product which is not adsorbed on the catalyst surface. The method was applied to the cracking of cumene on HY and CaY.
Prediction of heats of mixing of liquid mixtures by an analytical group solution model
Authors: Nguyen T. H. , Ratcliff G. A.
Published: March 2009

An analytical group solution model has been developed for the prediction of heats of mixing of liquid mixtures using the Wilson equation. This procedure obviates some of the limitations and inaccuracies of the previous model, and is well suited to computer calculation. It was tested for a wide range of alcohol/alkane mixtures and gives good results.

The group Wilson parameters were generated from experimental data for methylene/hydroxyl mixtures at 15°C to 55°C. At temperatures within or close to this range, these group parameters allow prediction of heats of mixing of binary or multicomponent mixtures containing these two groups. No experimental data are required.
A comparison of recent axial dispersion correlations in liquid‐solid fluidized beds
Authors: Wen C. Y. , Fan L. S.
Published: March 2009

The axial dispersion correlations in liquid‐solid fluidized beds presented by Chung and Wen(1)and Krishnaswamy and Shemilt(8)are compared and the applicability of the correlations are discussed.
Some Observations on the motion of elongated bubbles in horizontal pipes
Authors: Aziz K. , Gregory G. A. , Nicholson M.
Published: March 2009

Results of a study of the flow of air‐oil mixtures in the elongated bubble flow pattern are presented, based on experiments conducted in a 1.014 inch diameter horizontal pipe. It is demonstrated that several well defined and reproducible sub‐regimes actually exist within the flow pattern usually designated as elongated bubble flow. Some previously unreported interrelationships between various measured parameters are noted and discussed. The experimental data are also used to test several existing correlations for the prediction of pressure drop and holdup in this flow regime.
Application of porous media models to the study of deep bed filtration
Authors: Payatakes A. C. , Rajagopalan R. , Tien Chi
Published: March 2009

Two porous media models — capillaric and Brinkman — were used for the study of deep bed filtration and to calculate the filter coefficient and the pressure drop increase during the course of filtration.

The filter coefficient was estimated with trajectory calculations which determine the path of particulate matters as they pass through the filter. A number of relevant forces were included and their effects determined. The Brinkman model was found to give good agreement with experimental results and the filter coefficients based on capillaric model were approximately one to two orders of magnitude lower than experimental data.

Both models fail to give reasonable estimates on the pressure drop increase and the discrepancies between the model and the experimental values were two to three orders of magnitude. This is largely due to the failure of the models to distinguish the different roles played by the filter grains and by the particulate matters retained. The filter grains constitute a matrix of passages as conduits for the liquid flow, and the deposited particulate matters act primarily to modify these flow passages (i.e. to restrict the flow). Such a distinction is however not possible with the use of these models.
Axial dispersion in a pulsed plate column
Authors: Baird M. H. I.
Published: March 2009

A technique involving the indicator colour change in an acidbase reaction has been used to measure axial dispersion coefficients in a 15 cm diameter pulsed column. Data have been obtained mainly for single phase (aqueous) flow with two different types of plate at two different spacings. With coarsely perforated plates, the dispersion coefficient is proportional to (amplitude)2 times frequency, but semicircular unperforated baffle plates show a dependence on amplitude times frequency. These results are critically compared with published data, and two types of flow regime for axial dispersion are indicated.
Catalytic reduction of nitric oxide in the presence of oxygen in low concentration high velocity gas streams
Authors: Lamb A. , Tollefson E. L.
Published: March 2009

A small fixed‐bed catalytic reactor and a gas chromatographic analytical method were used to investigate the effects of oxygen on nitric oxide reduction by hydrogen over metal alloys. This work follows similar investigations, previously reported, into the reduction of nitric oxide with hydrogen in the absence of oxygen. The rate of oxygen consumption was directly proportional to hydrogen concentration but independent of oxygen concentration, at oxygen and hydrogen partial pressures of 4 — 7 × 10−3 atm., and 1 — 11 × 10−3 atm., respectively, and space velocities of 43,000 – 45,000 hr−3. The activation energy for Monel* alloy was 8.8 kcals* g* mole−1 over a temperature range 347 – 502°C

In comparing Monel and brass catalysts some selectivity in the reduction of nitric oxide in the presence of oxygen was observed. Depending on the conditions to which Monel has been subjected, its activity at a given temperature was found to vary with time from one level to another.
Measurement of total pressures for ethylene — propane mixtures
Authors: Elshayal I. M. , Lu B. C. ‐Y.
Published: March 2009

Isothermal P‐x data for the binary system ethylene‐propane were measured at four temperatures by means of a total pressure apparatus. Equilibrium vapor compositions were calculated with the supporting properties obtained from the Clausius Equation of state. In the calculation, the parameters of the Clausius Equation were considered to be temperature‐dependent. The validity of the apparatus and the proposed method of calculation was established by comparing satisfactorily phase equilibrium values obtained in this study with those reported in the literature for the binary systems argon‐nitrogen and argon‐methane. In addition, several vapor compositions were also determined experimentally for the binary system ethylene‐propane to confirm the accuracy of the calculated results.
Microbial reactor design for synthetic protein production
Authors: Moo‐Young Murray
Published: March 2009

The physical factors that may affect the performance of a microbial reactor for producing syntlietic protein are reviewed in ternis of chemical engineering principles. In particular, it is shown that an appreciation of these principles can be used to maximize the productivity of synthetic protein from liquid‐hydrocarbon and cellulose fermentations.
The area affected by oil spills on land
Authors: Mackay D. , Mohtadi M.
Published: March 2009

Data have been compiled and analysed on the volume and area of 53 oil spills on land in Alberta. Comparable data are presented for smaller experimental spills in the Mackenzie Valley, North West Territories. From these spill data and consideration of the flow characteristics of oil on the permeable terrain of the Mackenzie Valley, an equation is derived to predict the likely area affected by an oil spill from the proposed Mackcnzic Valley Oil Pipeline, namely:‐

Spill Area (m2) = 53.5( Volume (m3) )0.89
The identification of residence time models by reacting tracer experiments
Authors: Parimi K. , Harris T. R.
Published: March 2009

It has been shown that the steady‐state conversion of tracers which react with nonlinear kinetics (NLRT) may be used to differentiate complete mixing from macro‐fluid behavior. This paper presents the results of theoretical and experimental studies which have demonstrated that the discriminatory power of NLRT techniques may be greatly increased if unsteady‐state pulse tests with reacting tracers are used instead of steady‐state conversion experiments. The method is shown to be sufficiently sensitive to differentiate among models of mixing which describe the results of inert tracer experiments with equal accuracy. The method was used to identify the position of a plug‐flow element in a plug‐flow mixing‐cell network and to differentiate between a Taylor dispersion system and a plug‐flow mixing‐cell network.
Solubility of propane in isomers of hexane and other non‐polar solvents
Authors: Fleury D. , Hayduk W.
Published: March 2009

Solubilities of propane at atmospheric pressure and for temperatures ranging from —15°C to 70°C are reported for a variety of solvents including hexane and the branch‐chained hexane isomers, for cyclohexane, perfluorohexane, benzene, ethylbenzene, metaxylene, carbon tetrachloride and carbon disulfide. These data, along with data from the literature, are used in comparing solubility behavior of propane and the other paraffin gases in a range of solvents.

While predictions of gas solubilities even in non‐polar solvents are still somewhat uncertain, it appears possible to estimate the solubilities of methane, ethane, propane or butane by extrapolation of known solubilities of these gases in a range of solvents. It is also possible to predict the temperature coefficient of solubility in solvents, such as benzene, which yield regular solutions.
The electroreduction of oxygen to hydrogen peroxide on fluidized cathodes
Authors: Oloman Colin , Watkinson A. Paul
Published: March 2009

The cathodic reduction of oxygen to hydrogen peroxide on fluidized beds of graphite has been studied. The cathodes were fluidized by an oxygen saturated solution of 0.1M NaOH, or by the simultaneous introduction of oxygen gas and hydroxide solution. With increasing current density, the current efficiency always decreased while the product peroxide concentration went through a maximum. In the two‐phase system the maximum peroxide concentration increased with bed height. Both current efficiency and the rate of peroxide production generally decreased with catholyte flowrate. For the three‐phase fluidized cathode the rate of peroxide production and the current efficiency increased with both catholyte and oxygen flowrate. Possible rate controlling steps are discussed. Current densities for both two phase and three phase fluidized beds were too low to be of commercial use.
Extraction of phenol from water with mixed solvents
Authors: Medir M. , Mackay D.
Published: March 2009

Distribution coefficient data ate presented for phenol at 25°C between water and nine mixed solvents. The binary solvent mixtures were n‐octane with n‐hexanol‐l, n‐octanol‐l and n‐decanol‐l; n‐octanol‐l with benzene carbontetrachloride, cyclo‐hexane, kerosene and butyl acetate; and n‐butyl acetate with benzene. All alcohol mixtures exhibited a positive deviation from linearity in distribution co‐efficient, maxima being obtained for mixtures of n‐octanol‐l with n‐butyl acetate and benzene. The data are correlated empirically and the nature of the chemical associations discussed. Practical implications are that esteralcohol mixtures may be the preferred solvents for phenol extraction from water since these mixtures have distribution coefficients significantly greater than either pure solvent.
Heat transfer rate predictions in condensation on droplets from air‐steam mixtures
Authors: Kulic E. , Rhodes E. , Sullivan G.
Published: March 2009

This paper describes simulations of the combined heat and mass transfer to single water droplets falling freely in air‐steam mixtures. The effects of droplet size, initial velocity, and concentration of steam in the mixture are discussed. The results are to be used in the design synthesis of steam dousing chambers in which sprays containing droplets whose diameters range as high as 6 mm. are used.
Effect of high temperature treatment on the properties of fe‐mo oxide catalysts
Authors: Aruanno Jorge , Wanke Sieghard
Published: March 2009

In this study the structural and compositional changes that Fe‐Mo oxide catalysts undergo during treatment at elevated temperatures were investigated. Commercial and laboratory prepared catalysts were examined. The changes in catalyst properties were determined by low temperature nitrogen adsorption, scanning electron microscopy, X‐ray diffraction, X‐ray fluorescence and thermogravimetric analysis. The activities of the catalysts for the oxidation of methanol in air to formaldehyde were measured using an integral bed reactor.

The results showed that treatment at elevated temperatures resulted in the growth and segregation of Fe2(Mo04)3 and Mo03 crystals resulting in a loss of specific surface area. The changes in specific activity can be explained in terms of molybdenum depletion from a molybdenum rich iron molybdate phase.
Effects of charge stock composition on the kinetic parameters in catalytic cracking
Authors: Pachovsky Roman A. , Wojciechowski Bohdan W.
Published: March 2009

It is shown that the addition of wax to a wax free neutral distillate has no synergistic effect on the initial rate constant for cracking. The initial rate constant is in fact found to be a linear function of the mole fraction of wax in the feed. At the same time it is found that the activation energy for the cracking of pure wax is ˜ 48 kcal/inole and is some 4 kcal/mole lower than the activation energy for the cracking of the wax free aromatics and cyclic aliphatics. We are therefore led to believe that the initial rate constant for the catalytic cracking of any mitxure of compounds is simply the sum of the individual rate constants weighted by their respective mole fractions.

It is also shown that the introduction of wax into the wax free feed results in an increased apparent order of the overall reaction and in more rapid decay of catalyst activity.
Steady state and dynamic studies of a multi product chemical plant
Authors: Johnson A. I. , Lozada A. , Anvari M. , Stephanopoulos G. , Weng P.
Published: March 2009

Steady state and dynamic behaviour studies of a fat hydrolysis plant for handling a variety of feeds to produce a range of fatty acids for detergents and soaps are presented. These include optimization techniques for the steady state. Alternate techniques for product change are presented, and simulated using a dynamic simulator. The computer systems used are modular.
Particle segregation in a fluidized bed
Authors: Chen J. L.‐P. , Keairns D. L.
Published: March 2009

Particle segregation data at low gas velocity, near the minimum fluidizing velocity, are presented for particles of different size (150 to 2800 μm) and density (720 to 2800 kg/m3) in a fluidized bed. Phase diagrams similar to those of liquid‐solid systems are developed to present the results. The data were collected in a 100 mm diameter unit operating at pressures up to 660 kPa and a 114 mm diameter unit at atmospheric pressure.

The particle segregation data were obtained to provide design and operating criteria for a two‐stage. i.e., an agglomerating combustor/gasifier and a devolatilizer/desulfurizer, fluidized bed coal gasification process to produce low heating‐value gas (890‐1350 K‐cal/m3) for power generation. The data indicate that the criteria for particle separation can be achieved if the operating gas velocity is close to the minimum fluidizing velocity of the dense particles, that is, agglomerated ash, and spent dolomite.
Corona‐induced autohesion of polyethylene: Dependence of bonding on frequency and power consumption in various gases
Authors: Stradal M. , Goring D. A. I.
Published: March 2009

The autohesion of polyethylene sheets was markedly improved by corona discharge treatments in oxygen, nitrogen, argon and helium. Equal bond strength was produced by an equal number of discharge cycles regardless of the time or frequency of application. At a given operating voltage the power consumed in a discharge rather than the chemical nature of a gas proved to be a factor controlling the enhancement of autohesion. The detrimental effect of the oxidation upon autohesion was noted after a prolonged treatment in an oxygen corona.
Experimental testing of the hydrodynamic collision model of fine particle flotation
Authors: Reay David , Ratcliff G. A.
Published: March 2009

Flotation rates of glass beads and of latex particles have been measured as a function of particle size using very small bubbles. With glass beads the observed rate versus size relationship agreed quite well with the prediction of a simple hydrodynamic collision model, but that found with latex particles did not. It is suggested that electrical forces may have to be taken into account when the particles have a significant zeta potential. With both types of particle, the relationship between flotation rates measured at two different bubble sizes is consistent with the model's predictions.
Laminar natural heat transfer from an isothermal sphere to non‐newtonian fluids
Authors: Liew K. S. , Adelman M.
Published: March 2009

An experimental study of natural convection heat transfer conducted with water and thirteen aqueous polymer solutions obeying the power‐law model, varying in flow behavior index from 0.3 to 0.99, and consistency index between 10 and 5 × 103, showed that the behavior of these solutions justifies the theoretical treatment of this phenomenon proposed by Acrivos(10). The heat source was an internally electrically heated copper sphere, 5 inches in diameter, and designed to provide an isothermal surface.
Mass transfer from crystalline surfaces in a turbulent impinging jet part I. Transfer by erosion
Authors: Giralt Francesc , Trass Olev
Published: March 2009

Mechanical erosion from two crystalline coating materials, naphthalene and trans‐cinnamic acid, in submerged turbulent impinging jets of water has been studied. In the absence of diffusion, the observed erosion rates in the wall jet region vary linearly with wall shear stress. Threshold shear stress values below which erosion may be neglected have been defined for both coating materials. Erosion rates in the impingement region also depend on the shear stress which, depending on the crystalline grain size, may interact with pressure forces.
Non‐isothermal pressure‐drop in non‐newtonian laminar flow
Authors: Mahalingam R. , Coulson J. M.
Published: March 2009

Experimentally‐measured pressure‐drop data are compared with analytical predictions for laminar flow of non‐Newtonian fluids in circular conduits, under constant wall heat flux boundary condition. The non‐Newtonian pseudoplastic solutions used in this study were aqueous solutions of Methocel® (0.75% – 2% w/w) and Carbopol 934® (0.15% – 0.50%). The heated section was 0.792″ i.d. × 1″ o.d. × 112.87″ long brass tube with an additional length of 68″ acting as the entrance length. The analytical predicitions on pressure drop have been based on numerically computed or analytically‐postulated temperature profiles. The mean deviation of the predicted values from the experimental values is of the order of ±8%.
Influence of fluid rheology on circulation, mixing and blending
Authors: Chavan V. V. , Ford D. E. , Arumugam M.
Published: March 2009

The measurements of the integral physical quantities such as circulation, mixing and blending times for helical screw impellers with the draught tube are presented in this paper. The influence of shear‐thinning and elastic properties of the liquids on these quantities are analysed both experimentally and theoretically.

The overall circulation was found to be independent of the shear‐thinning character of the liquid. The influence of elasticity is considered in the light of the existing knowledge on sonic simple flow situations. A relation which incorporates the geometry of the mixer and the rheological properties of the liquid is proposed.

The mixing and blending time results are analysed and related to the hydrodynamics using the laminar mixing approach of Mohr and his co‐workers. Although the analysis is approximate, it provides a useful tool in explaining the effects of rheology. It also suggests a way to estimate the blending times.
Density prediction of multicomponent aqueous solutions from binary data
Authors: Teng Tjoon‐Tow , Lenzi Fabio
Published: March 2009

An isopycnotic (equal density) relation has been developed for non‐interacting solutes in multicomponent aqueous solutions. The relation can be used to estimate ternary densities from binary data. Predicted and observed values for 26 systems at 25°C are compared, usoing Young's rule, the isopycnotic, and other methods. Young's rule and the isopycnotic methods give relatively better predictions (<0.2% error) even when applied to concentrated solutions.
Erco award 1975: Basic research in particle technology and some novel applications
Authors: Capes C. E.
Published: March 2009

Particle technology is concerned with the problems of dealing with matter in a finely‐divided state. Its importance cannot be over emphasized today in view of its relevance, for example, to waste treatment, environmental problems and the efficient recovery and beneficiation of ores and fossil fuels.

This paper discusses the author's involvement in particle technology research relating to fluid‐particle systems and size enlargement processes. The innovative solution of practical problems through development of a background of knowledge from continuing basic studies is emphasized. Specific examples are cited in the areas of separation by particulate gas fluidization, dence phase conveying, upgrading of waste particulate material, balling circuit design and operation, and the beneficiation of coal fines with tailings recovery.
Developments in hydrotransport
Authors: Shook C. A.
Published: March 2009

Developments in the movement of solids by liquids in pipelines are summarized with particular emphasis upon more recent work. In the case of Capsule transport there have been notable advances in understanding of the flow process and in data correlation. Thus it is now possible to predict energy consumptions, in some circumstances at least. For slurry transport the basic problem of predicting minimum operating velocities and energy consumptions still requires recourse to experiment or practical experience. Some theoretical progress has been made and there have been many interesting studies of other problems associated with operating slurry pipelines.
Liquid solidification in combined hydrodynamic and thermal entrance region of a circular tube
Authors: Hwang G. J. , Sheu Ja‐Pung
Published: March 2009

The paper presents a theoretical and experimental investigation of liquid solidification in the combined hydrodynamic and thermal entrance region of a circular tube with a uniform wall temperature. The theoretical solution assumes that axial variations in liquid‐solid interface are gradual and considers that effects of radial velocity component are significant in the entrance region. The theoretical analysis yields profiles of liquid‐solid interface, pressure drop and heat transfer coefficient for the cases of Pr = 7 and 10.

Experimental work using water as a working medium was carried out to verify the theoretical result by employing two double‐pipe heat exchangers with a small inner tube diameter to prevent free convection effects. A series of experimental data was obtained to calculate the mean heat transfer rate. Comparison between the experimental data and the theoretical results is made. Reasonable agreement is observed.
Alumina trihydrate crystallization. Part 1. Secondary nucleation and growth rate kinetics
Authors: Halfon A. , Kaliaguine S.
Published: March 2009

The kinetics of crystallization of alumina trihydroxide (hydrargillite) from caustic aluminate solutions of industrial composition (second stage BAYER process) were studied in a laboratory batch isothermal crystallizer. The yield and crystal size distribution of precipitate with time were obtained by varying the initial seed concentration.

In this paper, the mass balance was used to determine nucleation and growth rate kinetics. First, from among the laws available in the literature, those which applied to alumina trihydrate crystallization were defined (model A). Kinetic constants of this model were calculated from experimental results. Then, a model based on a secondary nucleation mechanism was proposed (model B) that fits experimental data, and explains the induction periods found in the decomposition of aluminate solutions, even when seeds are present.
A new technique for the measurement of ternary molecular diffusion coefficients in liquid systems
Authors: Alimadadian A. , Colver C. Phillip
Published: March 2009

A double Savart plate birefringent interferometer was used to study the diffusional behavior of the ternary system. Acetone (1) – Benzene (2) – Methanol (3). The ternary diffusion coefficients were measured at 9 composition points covering the entire ternary diagram. The binaries forming the borders of the ternary diagram were also studied. The ternary diffusion coefficients at one composition point of the ternary system Actone (1) – Benzene (2) – Carbon tetrachloride (3) were measured and compared with previously reported data of Cullinan and Toor(18), obtained by diaphragm cell method. Validity of the birefringent interferometric measurements when applied to the ternary liquid systems was confirmed through this comparison.
Criterion for initial contraction or expansion of three‐phase fluidized beds
Authors: Epstein Norman
Published: March 2009

Some beds contract and others expand when gas bubbles are introduced into the bottom of a liquid‐fluidized bed. A quantitative criterion for predicting which of these two events will occur in any particular case, derived in an earlier paper, is tested against experimental data from the literature and shown to predict all the observed trends with various process variables correctly.
Wet air oxidation of soluble components in waste water
Authors: Pruden B. B. , Le H.
Published: March 2009

Wet Air Oxidation (WAO) can be used to remove combustible materials from wastewater. This process takes place in the liquid phase at 200 to 300°C and up to 2500 psi (17.3 MPa) with air present.

In this work, the WAO of phenol, which is soluble and volatile, and nitrilotriacetic acid (NTA) which is soluble and non‐volatile were studied. The process was carried out on a continuous basis in an unmixed 1 liter, bubbling reactor with conditions up to 250°C and 2200 psi (15.3 MPa) and liquid residence times from 15 minutes to two hours.

A model which describes the effect of pressure, temperature and liquid residence time on the reaction was developed and used to compare the results for phenol and NTA oxidations.
Measurement of vapor‐liquid equilibria using a semi‐continuous total pressure static equilibrium still
Authors: Ronc M. , Ratcliff G. R.
Published: March 2009

The total pressure static equilibrium still designed by Gibbs and Van Ness has been modified to increase its accuracy. It was tested by comparing calculated vapor compositions and excess Gibbs free energies with literature data for mixtures of ethanol and n‐heptane at 30°C. Experimental data are presented for 1‐pentanol/n‐hexane mixtures at 30° and 50°C, for 1‐pentanol/n‐pentane mixtures at 30°C, and for 1‐butanol/n‐pentane mixtures at 30°C.
Vapor pressures of high‐boilings complex hydrocarbons
Authors: Smith George , Winnick Jack , Abrams D. S. , Prausnitz J. M.
Published: March 2009

Since vapor pressures of very high‐boiling hydrocarbons are of increasing interest in energy‐related processes, a new correlation has been established for estimating these vapor pressures over a wide range of temperature. The new SWAP correlation, based on Prigogine's theory for polysegmented molecules, is particularly useful for hydrocarbons (and petroleum cuts or coal tars) which deviate from normal‐paraffin structure: branching, saturated and unsaturated rings. Extensive comparison with experimental data shows that whereas for normal paraffins SWAP gives results comparable to those obtained by previously‐published correlations, SWAP gives significantly better results for large aromatic, naphthenic and branched hydrocarbons. To use SWAP, the only input data required are T10 (boiling point at 10 mm Hg) and approximate characterization of molecular structure.
The thermal conductivity of porous catalyst compacts
Authors: Sharma C. S. , Hughes R.
Published: March 2009

Thermal conductivities of pellets made from porous catalyst supports and supported nickel catalysts have been measured by a steady state method. Results are presented in the form of plots of thermal conductivity against macropore voidage and the experimental data are compared with the predictions of two models.
Gas absorption with consecutive chemical reaction: Absorption of carbon dioxide into aqueous amine solutions
Authors: Sada Eizo , Kumazawa Hidehiro , Butt M. A.
Published: March 2009

Experiments were carried out over a wide range of contact time for the absorption of carbon dioxide into aqueous amine solutions. It was suggested from the experimental results with a laminar liquid‐jet, a wetted wall column and a quiescent liquid absorber that the present absorption processes should be analyzed by a gas absorption with the consecutive reaction of the form of A + 2B →kI R and A + R →kII Products. The values of rate constants for the second‐order first reaction step (k1) for the diethanolamine and triethanolamine were estimated as 1340 and 16.8 1/mol‐sec, respectively. The value of rate constant for the second reaction step was found to be constant irrespective of the liquid reactant.
Benedict‐webb‐rubin parameters for ethanol
Authors: Gomez‐Nieto Mateo , Thodos George
Published: March 2009

Experimental PVT measurements available in the literature for ethanol have been utilized to establish the BWR parameters for this substance using a nonlinear regression analysis involving 300 experimental points for reduced densities up to ρR = 1.80. The resulting parameters reproduce pressures for these 300 points, with an average deviation of 2.60% and predict the vapor pressure behavior between the normal boiling point and the critical point with an average deviation of 0.91%. This treatment is applied for the first time to the PVT behavior of an alcohol and indicates that the BWR equation of state could well be extended in application to include other oxygenated organic compounds receiving considerable interest in the currently changing energy emphasis.
Mass transfer between solid spheres and oscillating fluids — A critical review
Authors: Taweel A. M. Al , Landau J.
Published: March 2009

Relative oscillatory motion between solid particles and a fluid increases the rate of interphase mass transfer due to the establishment of secondary flows (acoustic streaming). A critical survey of published data shows that mass transfer is well correlated by a theoretically founded dimensionless relation of the form

where K, a, b and d depend on the Schmidt number. The equation successfully correlates experimental data for both gases and liquids over a range of frequencies F < 1 Hz to F ⋍ 106 Hz, provided the amplitude to diameter ratio A/D is below 0.75. At higher values of this parameter, NSh is better predicted by a quasi‐steady model which no longer depends on A/D.

Based on a paper presented at the 26th Canadian Chemical Engineering Conference, Montreal, Quebec, November 2–5, 1975.
Absorption of ammonia in a batch bubble column
Authors: Baird M. H. I. , Kim S. D. , Elley D. , Webster A.
Published: March 2009

The batch neutralization of dilute hydrochloric acid by ammonia in a 10.16 cm i.d. bubble column has been examined. Experimental results agree with a diffusion‐type mixing model when 5.08 cm disc baffles are present, but agreement is only approximate with 7.62 cm diameter baffles. Axial dispersion coefficients have been determined and compared with published data. A simple batchwise procedure for evaluating bubble columns is suggested.
Absorption with first order chemical reaction into a liquid film in laminar flow
Authors: Stepanek J. B. , Achwal S. K.
Published: March 2009

Absorption with first order chemical reaction into a liquid film in laminar flow was analysed for the cases of zero and finite resistance in the gas phase. The result was obtained in terms of a sum of a hyperbolic function and an infinite series of hypergeometric functions. The one or two parameters entering the solution contain the rate constant and the mass transfer coefficient in the gas phase, respectively. Ten eigenvalues and integration constants were calculated for several values of the reaction rate parameter for the simpler case of no resistance in the gas phase. The analysis of the results showed that the length of the entrance region can vary substantially depending on the reaction rate constant.
Segregation effects on consecutive competing reaction in a CSTR
Authors: Truong Khac Trong , Methot J.‐Clavde
Published: March 2009

The steady state behaviour of a continuous stirred tank reactor at a constant temperature of 30°C was studied using the saponification of ethylene glycol diacetate by sodium hydroxyde. The reactor studied was respectively fed by premixed and unmixed reactants. Experimental values of the level of segregation lay within the range of 0.15 to 0.5. The level of segregation has been correlated with the physicochemical dimensionless group k1CAo/β and we may conclude that the reactor would be in a state of maximum mixedness when the magnitude of this group is smaller than 10−4.
Two and three phase equilibrium calculations for systems containing water
Authors: Peng Ding‐Yu , Robinson Donald B.
Published: March 2009

A recently proposed two‐constant equation of state is used to predict the phase behaviour of systems exhibiting a water‐rich liquid phase, a hydrocarbon‐rich liquid phase and a vapor phase. The algorithm proposed is efficient and thermodynamically rigorous and it converges significantly faster than earlier models. Representative calculations are shown for the methane‐n butane water system, the n butane‐1 butane‐water system, and a synthetic six‐component hydrocarbon mixture containing waer.
Characterisation of inelastic power‐law fluids using falling sphere data
Authors: Uhlherr P. H. T. , Le T. N. , Tiu C.
Published: March 2009

Two simple methods are presented for the characterization of inelastic power law fluids from falling sphere data. The methods involve the application of shear rate or shear stress correction factors which have been derived theoretically using Slattery's solution for creeping flow about spheres. Flow curves obtained using these methods are in excellent agreement with those measured on a Weissenberg rheogoniometer for 0.83 ≤ n ≤ 1.0.

The experimentally determined drag coefficients are found to be in good agreement with the predictions of Slattery's creeping flow first approximation solution.

The wall correction factors of Faxen and Francis appear to be valid for inelastic non‐Newtonian fluids up to a diameter ratio of at least 0.08.
The role of mass transfer in trickle‐bed reactors
Authors: Goto S. , Watabe S. , Matsvbara M.
Published: March 2009

Steady state characteristics of a trickle‐bed reactor in which the gas solute governs the reaction with linear kinetics are analyzed. The efficiency of the reactor is defined as the ratio of the actual production rate to the intrinsic reaction rate and the dependence of the efficiency on Damkohler number and Peclet number is investigated. Three sets of published experimental data are used to evaluate the efficiency. Also, the criterion for negligible axial dispersion is studied in comparison with Mears' criterion.
Segregation effects on consecutive competing reaction in a CSTR
Authors: Truong Khac Trong , Methot J.‐Claude
Published: March 2009

The steady state behaviour of a continuous stirred tank reactor at a constant temperature of 30°C was studied using the saponification of ethylene glycol diacetate by sodium hydroxyde. The reactor studied was respectively fed by premixed and unmixed reactants. Experimental values of the level of segregation lay within the range of 0.15 to 0.5. The level of segregation has been correlated with the physicochemical dimensionless group k1C/β and we may conclude that the reactor would be in a state of maximum mixedness when the magnitude of this group is smaller than 10−4.
The thermodynamics of the hydrogenation of oxides of carbon
Authors: Anderson Robert B. , Lee Chung‐Boon , Machiels Joseph C.
Published: March 2009

The thermodynamics of the hydrogenation of CO and CO2 is summarized. Equilibrium compositions for a number of reactions proceeding simultaneously to yield a number of hydrocarbons and oxygenated organic molecules are reported. If methane is included in these calculations, methane is the predominant product; therefore, for the production of other molecules selective catalysts are required.

For producing methane the hydrogenation of CO2 rather than CO may be advantageous, because the reaction is less exothermic. Thermodynamic calculations and results of tests on Raney nickel in a small tubular reactor show that high yields of methane can be obtained in the hydrogenation of both CO and CO2 at temperatures as high as 450°C.
pH Control of a continuous precipitator
Authors: Attarian C. , Baker C. G. J. , Svrcek W. Y.
Published: March 2009

The size distribution of precipitates formed in a double decomposition reaction has been found previously to be highly sensitive to pH. Consequently, automatic control of pH is necessary to maintain a constant product size distribution. In the present study, steady‐state, dynamic, and pH control tests were performed on a continuous precipitator in which calcium carbonate was produced. Agreement between the experimental dynamic response and that predicted by a model based on equilibrium and stoichiometry was poor. However, satisfactory feedback control of the pH was achieved using proportional plus integral action. Simultaneous measurements of the precipitate size distribution using a Coulter Counter demonstrated that this resulted in good conrol of the mean paricle size.
A mathematical model for pyrolysis of a solid particle: Effects of the lewis number
Authors: Fan L. T. , Fan Liang‐Shih , Miyanami Kei , Chen T. Y. , Walawender W. P.
Published: March 2009

A transient analysis of a fluid‐solid pyrolysis system in which a solid is pytolyzed to form a fluid product and a solid product is presented. The analysis, based on utilization of the so‐called volume reaction model, takes into account the simultaneous heat and mass transfer phenomena in the particle being pyrolyzed. Variations of physical parameters with respect to temperature and/or solid concentration are not neglected. Effects of the Lewis number on the solid conversion, the fluid and solid concentration distributions, and the temperature profile in the particle are examined. The results are graphically presented and interpreted.
A variable eigenvalue approach to the solution of phase‐change problems
Authors: Ozisik M. N. , Guçeri S. I.
Published: March 2009

A zeroth order variable eigenvalue approach is used to solve the melting (or solidification) problem for a slab initially at a uniform temperature different from the melting temperature and two boundaries maintained at specified temperatures. The accuracy of the method is investigated by applying this approach to obtain a closed form solution for the melting of a semi‐infinite medium for which analytical solution is available and comparing both results.
Salt effect in distillation: A literature review II
Authors: Furter William F.
Published: March 2009

A salt dissolved in a mixed solvent is capable, through preferential association or other structure‐related effects in the liquid phase, of altering the composition of the equilibrium vapor phase. Hence salt effect on vapor‐liquid equilibrium relationships provides a potential technique of extractive distillation for difficult separations. The literature pertaining to salt effect in vapor‐liquid equilibrium and in extractive distillation over the period 1966‐present is reviewed, and also the remainder of work up to 1966 not covered in the Part I review.
Single collector analysis of collection mechanisms in water filtration
Authors: Rajagopalan R. , Tien Chi
Published: March 2009

A complete trajectory analysis of particle collection on single spheres, which includes all the known collection mechanisms and forces, is presented here for later experimental verification. The results show that the surface interactions between the collector and the particles have negligible influence on collection rate except to determine whether the surface conditions are favorable or unfavorable for collection. It is also evident that the hydrodynamic retardation of the particle in the neighborhood of the collector can reduce deposition significantly (by 50% or more), but such effects may be negligible in view of the usually wide scatter of filtration data. This paper also provides examples of how the single collector analysis can be directly applied to modelling retention in packed beds. To make the work easily accessible to the readers, all the basic concepts necessary for future application of the trajectory analysis are presented clearly along with a table containing all the relevant forces and torques acting on the particle. An experimental analysis of the results reported here is presented in a subsequent publication.
Analysis of combined forced and free convection across a horizontal cylinder
Authors: Mucoglu A. , Chen T. S.
Published: March 2009

A new analysis is performed to study the flow and heat transfer characteristics of laminar combined forced and free convection about a horizontal cylinder. The transformed conservation equations of the nonsimilar boundary layers are solved by a finite difference method. Numerical results for gases having a Prandtl number of 0.7 are presented for buoyancy parameters which cover the entire domain of the mixed convection, ranging from pure forced convection to pure free convection. It is found that both the local wall shear and the local heat transfer rate (1) increase with increasing buoyancy force for assisting flow, (2) decrease with increasing buoyancy force for opposing flow, and (3) depend very strongly on the variation of the local free stream velocity, particularly for small to moderate buoyancy forces. With regard to the heat transfer results, the buoyancy force effects on forced convection are found to be important for Gr/Re2≥ 1.93 and ≤ –1.60, respectively for assisting and opposing flows, whereas the inertia force effects on free convection become significant for Re2/Gr ≥ 0.012.
Effect of alkalinity on the scaling of simulated cooling tower water
Authors: Morse Robert W. , Knudsen James G.
Published: March 2009

The scaling behavior of simulated cooling tower water on a heat transfer surface was investigated. The alkalinity was the main parameter investigated. The fouling vs. time curves were fitted to the equation

which was derived from a simple model of the fouling process.

Correlation coefficients ranging from 0.81 to 0.987 were obtained in fitting the data to the model. No particular pattern was observed for delay times and they appeared not to have a significant influence on the asymptotic fouling resistance. The latter is a complex function of the alkalinity but generally increases with alkalinity for the conditions of the experiment. Scale strength appears to be a strong function of the non‐calcium carbonate components of the scale.
The removal of sodium, cadmium and chromium ions from dilute aqueous solutions using foam fractionation
Authors: Kubota Katsuyuki , Hayashi Shinya
Published: March 2009

Cationic metallic ions such as sodium, cadmium and chromium were flotated from aqueous solution by using foam separation or foam fractionation technique in a continuous flow system. Experimental results showed a considerable difference between mono‐ or divalent and trivalent metallic ions in their affinity to neutralize the negatively charged surface layer formed at the gas‐liquid interface. This was verified by use of the Gouy‐Chapman diffuse double‐layer theory, except for the case of high concentration of the co‐existing collector which formed miscellaneous metal‐collector complexes.
A mathematical model for pyrolysis of a solid particle — effects of the heat of reaction
Authors: Miyanami Kei , Fan Liang‐Shih , Fan L. T. , Walawender W. P.
Published: March 2009

A transient analysis of the effects of the heat of reaction in a solid pyrolysis system is presented. Two cases, one characterizing the heat‐transfer‐controlled reaction and the other self‐sustaining reaction, are analyzed. To carry out the numerical simulation, utilization is made of the volume reaction model which takes into account the simultaneous heat and mass transfer phenomena, and the method of line which utilizes the second order centered finite difference scheme for the spatial discretization. Effects of the heat of reaction on the solid conversion, solid reactant, and fluid product concentration profiles, temperature distribution, enthalpy, and average fluid product concentration in the particle are examined. The results are graphically presented and interpreted.
Reduced dynamic model of a fixed bed reactor
Authors: Mcgreavy C. , Naim H. M.
Published: March 2009

The solution of dynamic distributed parameter models describing complex highly exothermic reactions in fixed bed reactors usually requires excessive computation times which are too demanding for detailed explorations. A lumping technique has been applied to a dynamic distributed parameter model, in which the radial differential operators have been approximated and effectively replaced by simple algebraic expressions by redefining the dependent variable. The resulting reduced model retains the accuracy of description and the necessary structure which is implicit in the full set of equations. This has been achieved by relating a suitably defined set of pseudoparameters to the chemical and physical processes taking place. The direct benefit of this is that the computation time and storage requirements have been reduced to a more realistic level for design purposes.