bluuebunny/crossref_metadata_2025 huggingface dataset:
Aggregate behaviour of liquid fluidised beds
Authors: Gibilaro L.G. , Hossain I. , Foscolo P.U.
Published: March 2009

New and long published experimental observations of the onset of aggregate (bubbling) behaviour in liquid fluidised beds are shown to be in agreement with the predictions of a recently published model of the fluidisation process. For a given liquid, the transition from particulate to aggregate fluidisation depends on both the density and size of the suspended particles: the lower the particle density the larger is the size necessary for a transition to occur: thus for fluidisation by ambient water, lead particles larger than 200 μm and soda glass particles larger than 2000 μm will exhibit aggregate behaviour; below a critical particle density no such transition is possible.
Measurement of voidage in the fountain of a spouted bed
Authors: Waldie B. , Wilkinson D. , Mchugh T.G.P.
Published: March 2009

A γ‐ray technique is described for measuring the distribution of fractional voidage in the fountain of an air spouted bed. What appear to be the first experimental data on fountain voidage are presented. For the relatively shallow, 160 mm diameter, conical spouted bed studied, fountain fractional voidage is quite high, 0.88 and upwards. Generally voidage increases with height up the fountain, apart from a plateau or slight fall part way up. This trend differs from that proposed by Grace and Mathur in a theoretical model for a deeper cylindrical spouted bed. Fountain voidage is shown to depend on air flow rate and on particle size distribution.
Hydropyrolysis of kraft hardwood and softwood black liquor
Authors: Gilbert Allan F. , Cooper Dave F.
Published: March 2009

The hydropyrolysis of hardwood and softwood derived black liquor was studied to develop material balance data and to investigate the potential yield of phenolic oils that might be obtained as chemical by‐products of a kraft pulp mill. Hydropyrolysis reactions on softwood liquors were found to be more efficient in char formation than those on hardwood liquors. The yield of extractible phenolic oils was low, around 20–30 percent of black liquor organics, but the yields of simple phenols determined by gas chromatography were found to be even lower at 1–5 percent on black liquor organics.
Structural changes in catalytic hydroprocessing of syncrude coker gas oil
Authors: Khorasheh Farhad , Gray Murray R. , Dalla Lana Ivo G.
Published: March 2009

A method of Structural Group Analysis (SGA) was used to characterize feed and liquid products from catalytic hydroprocessing using a commercial Ni‐Mo catalyst. Comparison of the structural profiles revealed significant changes in the concentration of various structural groups. SGA is a promising tool for investigating chemical changes in complex reacting systems.
Breakup of non‐newtonian emulsion jets
Authors: Kitamura Yoshiro , Shigeta Hiromoto , Kawata Toshio , Takahashi Teruo
Published: March 2009

The breakup of non‐Newtonian emulsion jets into drops was experimentally studied by ejecting both O/W and W/O emulsions vertically downward into stagnant air through nozzles. Breakup lengths of non‐Newtonian emulsion jets were found to be almost equivalent to those of Newtonian jets. Experimental breakup data establish that the static surface tension of the oil phase can be used as the surface tension of W/O emulsion jets, whereas the dynamic surface tension of aqueous surfactant solutions is used as that of O/W emulsion jets. Diameters of drops formed from non‐Newtonian emulsion jets are in good agreement with the prediction from the stability theory previously developed by the authors. When the rheological index in a power law model is appreciably smaller than unity and the Ohnesorge number is significantly large, however, drop sizes are larger than the prediction because of the profile relaxation in jets. The critical velocity of emulsion jets, either O/W or W/O emulsion, is significantly lower than that of homogeneous Newtonian jets.
Mass transfer between solid particles and liquid in a three phase fluidized bed
Authors: Prakash A. , Briens C. L. , Bergougnou M. A.
Published: March 2009

Particle‐liquid mass transfer in a co‐current three‐phase fluidized bed of glass beads, water and air was studied with two measurement techniques. Both techniques measured the weight loss of a few particles coated with benzoic acid in a bed of inert glass beads. The effects of liquid and gas velocities, gas distribution and surface active agents on particle‐liquid mass transfer in a three‐phase fluidized bed were thus determined. In the absence of surface active agents in the liquid, particle‐liquid mass transfer rates in a three‐phase fluidized bed were up to 30% higher than in the corresponding liquid fluidized bed. When surface active agents were added to the liquid, the particle‐liquid mass transfer rate was increased by up to about 100% in the three‐phase fluidized bed, relative to the liquid fluidized bed. The particle‐liquid mass transfer coefficient was found to be inversely proportional to the liquid hold‐up in the three‐phase fluidized bed.
Coke formation during naphtha pyrolysis in a tubular reactor
Authors: Kumar P. , Kunzru D.
Published: March 2009

The effect of run time, temperature, conversion and inlet steam‐to‐naphtha ratio on the rate of coke deposition during naphtha pyrolysis in an annular tubular reactor has been investigated. Rates of coke deposition increased with increasing temperature, conversion and inlet naphtha partial pressure. Pyrolysis and coking models available for naphtha cracking were used to calculate the total coke deposited by treating the temperature difference between the reacting fluid and the outer reactor wall as a parameter. For all the runs, the experimental and calculated coking rates were in close agreement for an assumed temperature difference of 35‐45°C.
Flow through porous media of a shear‐thinning liquid with yield stress
Authors: Al‐Fariss T. , Pinder K. L.
Published: March 2009

Darcy's law for the laminar flow of Newtonian fluids through porous media has been modified to a more general form which will describe the flow through porous media of fluids whose flow behavior can be characterized by the Herschel‐Bulkley model. The model covers the flow of homogeneous fluids with a yield value and a power law flow behavior.

Experiments in packed beds of sand were carried out with solutions of paraffin wax in two oils and with a crude oil from the Peace River area of Canada. The model fitted the data well.

A sensitivity analysis of the fitting parameters showed that the model fit was very sensitive to errors in the flow behavior index, n, of the Herschel‐Bulkley model. A comparison of the “n” values calculated from viscometer measurements and from flow measurements agreed well.

A more general Reynolds number for flow through porous media, which includes a fluid yield value, was developed. The data were fitted to a Kozeny‐Carman type equation using this Reynolds number. The constant in the Kozeny‐Carman equation was determined for the two packed beds studied using Newtonian oils.

The data could all be represented, within the experimental error, by the relationship f* = 150/Re*. Since the mean volume to surface diameter of the packing was determined by the measurement of its permeability to a Newtonian oil, assuming C' = 150, the new definition of the Reynolds number allows the direct use of the Kozeny‐Carman equation with Herschel‐Bulkley type fluids.
Simultaneous Absorption of Hydrogen Sulfide and Carbon Dioxide into di‐isopropanolamine Solution
Authors: Yih Siu‐Ming , Sun Chi‐Chun
Published: March 2009

The simultaneous absorption of hydrogen sulfide and carbon dioxide into di‐isopropanolamine (DIPA) solution was investigated in a 183 cm long, 2.72 cm OD wetted‐wall column at atmospheric pressure. The influence of liquid flow rate, gas flow rate, temperature and liquid concentration on the absorption rate, overall gas‐phase mass transfer coefficient and selectivity factor were studied at a constant gas feed ratio. The results show that the absorption rate of CO2 increases rapidly with increasing liquid flow rate (the Reynolds number of the turbulent liquid film ranges from 2600 to 4350) but increases moderately with increasing gas flow rate (G = 18‐91 L/min), indicating that it is liquid‐phase mass transfer controlled. In contrast, the absorption rate of H2S increases very slowly with increasing liquid flow rate but increases rapidly with increasing gas flow rate, indicating that it is gas‐phase mass transfer controlled. The absorption rate of CO2 also increases with increasing temperature (26‐80°C) but H2S absorption rate decreases with increasing temperature. When the concentration of DIPA solution increases from 0.2 to 2.6 mol/L, the absorption rate of both CO2 and H2S increases but with a larger rate of increase for CO2 For selective H2S removal, it is preferable to operate at low liquid and high gas flow rates, low temperatures and low DIPA concentrations.
Kinetics of growth and lactic acid production from whey permeate by Lactobacillus helveticus
Authors: Roy Denis , Leduy Anh , Goulet Jacques
Published: March 2009

Batch fermentation kinetics of Lactobacillus helveticus were examined in detail. The nature of the culture medium had a significant effect on the product synthesis mechanism. In a glucose synthetic medium, lactic acid produced by the non‐growth‐associated mechanism was less than that by the growth‐associated mechanism. In a lactose synthetic medium, the contribution of both mechanisms was approximately equal at the end of fermentation. In the whey‐yeast extract permeate medium, the contribution by the non‐growth‐associated mechanism was superior to that of the growth‐associated mechanism. Temperature and pH also influenced the relative contribution of the two mechanisms on the total production of lactic acid in whey‐yeast extract permeate medium. Under optimal conditions for temperature and pH, the contribution of non‐growth‐associated product formation was the highest among all temperatures, and the lowest among all pH's. The ATP concentration‐biomass concentration relationship in the batch fermentation process could be roughly approximated by a Luedeking‐Piret‐like equation.
A group‐contribution, continuous‐thermodynamics framework for calculation of vapor‐liquid equilibria
Authors: Wang Shao‐Hwa , Whiting Wallace B.
Published: March 2009

Continuous thermodynamics is extended to the calculation of vapor‐liquid equilibria with UNIFAC. For many mixtures of discrete compounds, the UNIFAC model is an efficient method for calculating vapor‐liquid equilibria of systems when experimental data are scarce or non‐existent. Such constraints are especially important in continuous mixtures.

The continuous distribution is characterized by model compounds chosen to reproduce the TBP analysis. The UNIFAC model is extended to systems including several gases, and the new parameters for several light gases are given.

The new algorithm is described in detail. Sample calculations are shown for several semi‐continuous systems.
Dimensionally invariant viscosity function
Authors: Stastna J. , De Kee D.
Published: March 2009

The use of classical dimensional analysis in viscosity modelling is discussed. The method suggests relations between model parameters and molecular characteristics of a polymeric system.
Gas holdup and gas entrainment of a plunging water jet with a constant entrainment guide
Authors: Funatsu Kazumori , Hsu Yung‐Chien , Kamogawa Takemi
Published: March 2009

The gas holdup and gas entrainment of a plunging liquid jet with a gas entrainment guide in an air‐water system was investigated. The measurement of the gas holdup was performed using an over‐flow method. The turbulent jet velocity calculated on an inside nozzle diameter in the range from 4.4‐26.5 m/s for this system has been used in our correlations. The gas holdup has been well correlated in terms of 1/H(v02 + 2gH1), H1 d0 and the gas entrainment in terms of 1/Hw(v02 + 2gH1), H1, d0. The jet power requirement was also obtained from experimental data.
Dispersed phase holdup and drop size distribution in pulsed plate columns
Authors: Prabhakar A. , Sriniketan G. , Varma Y. B. G.
Published: March 2009

Dispersed phase holdup was measured in a pulsed plate column for the kerosene‐water system under binary conditions and under solute transfer from dispersed to continuous and continuous to dispersed phases. The experimental data were satisfactorily modelled through a recirculation regime model.

The drop size distribution, measured by a photographic technique, exhibited a multinodal character at low agitation rates and high dispersed phase flow rate. Sauter mean drop diameter was found to depend on the agitation rate, the dispersed phase flow rate, the mass transfer direction and the plate free area. Correlations for d32 and the interfacial area were presented using Kolmogoroff's isotropic turbulence model.
Effect of zeta potentials of oil droplets and bubbles on flotation of oil‐in‐water mixtures
Authors: Okada Kenji , Akagi Yasuharu , Yoshioka Naoya
Published: March 2009

The effects of surface charges of oil droplets and bubbles in the oil‐in‐water flotation process were studied by a zeta potential apparatus which was specially designed to measure the zeta potential of bubbles. To measure the electrophoretic velocity of bubbles accurately, small bubbles whose rising velocities were less than 1 mm/s were introduced into an electrophoresis cell by a method of pressure reduction of a solution containing dissolved air, and the movement of the bubble in the cell was followed by moving the cell vertically at the same velocity as that of the rising bubble. It was found that the separation efficiency, n, for the flotation was strongly dependent on the zeta potentials of both the oil droplets and the bubbles. n increased as the zeta potentials of both the oil droplets and the bubbles decreased. Also n became the largest when the oil droplets were negatively charged and the bubbles were positively charged. Furthermore, a critical adhesion parameter, m=4πϵζpζb/kA, between oil droplets and bubbles was calculated by the heterocoagulation theory, using the value of the experimentally determined Hamaker constant, A=3.38x 10−20J, and the dependence of n on m was examined.
Flow pattern of the phases and liquid saturation in gas‐liquid concurrent downflow through packed beds
Authors: Sai P. S. T. , Varma Y. B. G.
Published: March 2009

Flow pattern was visually observed for non‐foaming and foaming Newtonian and non‐Newtonian liquids under concurrent downflow with air in packed beds using different configurations of column geometry and packins. Flow maps delineating the different flow regions were presented based on the present study as well as that of earlier investigations. The total and dynamic liquid saturation were experimentally measured and correlations were presented in terms of (i) the Lockhart‐Martinelli parameter, χ, and (ii) the flow variables.
Solubilities of propene, butane, isobutane and isobutene gases in n‐Octane, Chlorobenzene and n‐Butanol solvents
Authors: Hayduk W. , Asatani H. , Miyano Y.
Published: March 2009

Solubilities are reported for atmospheric pressure and temperatures of 298.15, 323.15 and 343.15 K for the gases propene, butane, isobutane and isobutene in the solvents n‐octane, chlorobenzene and n‐butanol. The solvents were chosen to investigate the effect of the nature of the solvent on gas solubility. The solvents range from the non‐polar (octane) to slightly polar (chlorobenzene) and to polar and associating (butanol). The order of gas solubilities in the slightly polar chlorobenzene is found to be closely related to the normal boiling points of the dissolving gases. A method for relating solubilities at various temperatures in similar polar and associating solvents is examined.
Dynamic analysis of changes in diffusion and sorption parameters in the reaction of SO2 with activated soda ash
Authors: Doǧu Gülsen , Keskin Alne , Doǧu Timur
Published: March 2009

Variations in pore structure cause significant changes in diffusion resistance and adsorption characteristics during the reaction of SO2 with activated soda. Breakthrough and moment analysis of the SO2‐activated soda ash reaction showed that the effective diffusion coefficient of SO2 in the solid product (mostly Na2SO3) was about three times smaller than its value in the original activated soda. About 30% of the diffusion flux of SO2 in the solid product was found to be due to surface diffusion. The adsorption equilibrium constant of SO2 on the solid product was found to be about half the value of the adsorption equilibrium constant on activated soda. It was also determined that SO2 was irreversibly adsorbed on the solid product Na2SO3 at 200°C and 3.7 atm. The gaseous product CO2 was not adsorbed on the solid product while it was slightly adsorbed on activated soda.
On‐line estimation of microbial specific growth‐rates: An illustrative case study
Authors: Dochain D. , Pauss A.
Published: March 2009

This paper deals with the on‐line estimation of the specific growth rate in a fermentation process in the case when a soluble product is measured on‐line. The proposed algorithm belongs to a larger class of on‐line estimation algorithms which present the following advantages: they do not require any analytical expressions for the specific growth rate; their theoretical stability and convergence have been emphasized; since their structure includes a filtering effect, the estimation results exhibit less erratic values for the specific growth rate than when obtained by direct calculation from the biomass concentration equation. Real‐life results on an ethanol producing process are presented. Finally. it is shown how estimation results can be used for modelling purposes.
Effect of benzene and thiophene on rate of coke formation during naphtha pyrolysis
Authors: Sahu Durjyogharan , Kunzrw Deepak
Published: March 2009

The effect of benzene or thiophene addition to the feed on the rates of coke formation during naphtha pyrolysis has been investigated in a jet‐stirred reactor at atmospheric pressure in the temperature range of 1073‐1103 K. In addition, the effect of temperature, space time, weight ratio of steam to naphtha and the material of construction on the rate of coke deposition was also studied.

The rate of coke formation increased as the temperature, space time and aromatic content of the feed was increased whereas it decreased with an increase in the weight ratio of steam to naphtha or the thiophene content of the feed. Addition of thiophene increased the rate of naphtha pyrolysis and significantly reduced the aromatic yields. Rates of coke formation for both thiophene‐free and thiophene‐containing naphtha could be modeled by power law expressions involving the aromatics.
Preparation and characterization of Pt/silicalite catalysts with high Pt loadings
Authors: Rangwala H.A. , Szymura J.A. , Wanke S.E. , Otto F.D.
Published: March 2009

Methods for preparing Pt/silicalite catalysts are described. Equilibration of silicalite, a pentasil zeolite, in aqueous solutions of Pt(NH3), Cl2 containing excess ammonia resulted in Pt/silicalite catalysts with Pt loadings of ≥7 wt%. The Pt/silicalite catalysts were characterized by hydrogen chemisorption, X‐ray diffraction and transmission electron microscopy. The characterization studies showed that the majority of the Pt in the heavily loaded catalysts was located in the silicalite pores, and the Pt dispersions in these catalysts exceeded 0.8.
Coal surface conditioning for electrostatic separation
Authors: Zhou G. , Brown J. D.
Published: March 2009

In analogy with froth flotation using chemical agents to enlarge the difference of hydrophobicity, this study was undertaken to examine the feasibility of enlarging the differences in surface work function of coal components to improve the electrostatic separation. Two coal specimens from Alberta having medium ash and low sulfur contents were used. Chemical agents having different physical and chemical properties were investigated in both batch and continuous operation. The results show that either maceral or ash forming mineral separations can be improved by surface treatment with organic chemicals. Improvements of more than 10% were observed. The results also show that some aromatic chemicals are better for coal maceral separation while some aliphatic agents improve ash forming mineral separation.
V‐L‐S multiphase equilibrium in bitumen‐diluent systems
Authors: James Neil E. , Mehrotra Anil K.
Published: March 2009

A multiphase flash algorithm is developed for the prediction of V‐L‐L‐S equilibrium. The algorithm uses the Patel‐Teja equation of state for the fluid phases and a separate model, based on vapour pressure, for the solid phase. A novel technique is presented for avoiding the phase disappearance problem commonly encountered in multiphase equilibrium calculations involving multiple fugacity models. The predictions are shown to be in good agreement with the data for several CO2 and hydrocarbons V‐L‐S systems.

This paper also presents new experimental data for the solubility of Peace River bitumen in n‐pentane, n‐heptane and n‐octane at atmospheric conditions, and these are compared with the model predictions.
Hydrodynamics of liquid‐liquid dispersion in ejectors and vertical two phase flow
Authors: Mukherjee Dibyendu , Biswas Manindra N. , Mitra Arun K.
Published: March 2009

Mixing of two immiscible liquids can be conveniently achieved in a liquid‐jet ejector system which utilizes the kinetic energy of a liquid‐jet to simultaneously aspirate and interdisperse the immiscible phases. In such a dispersion process energy dissipation occurs due to friction on the walls of the ejector throat and divergent diffuser, as well as due to mixing and interdispersion of the two phases. The paper deals with the analysis and quantification of these different energy losses.

Measurements have also been reported on pressure drop and holdup of two phase liquid‐liquid flow in a vertical column fitted to the ejector system. Correlations have been developed for predicting the irreversible pressure drop (in terms of a two‐phase friction factor) and the holdup on the basis of the physical and dynamic variables of the system. A term ‘degree of mixing’, defined as the ratio of the actual holdup fraction to the homogeneous holdup fraction, has been used to estimate the extent of mixing.
Biofluidization: Application of the fluidization technique in biotechnology
Authors: Schügerl K.
Published: March 2009

The applications of solid/liquid and/or solid/liquid/gas fluidized beds are considered in such areas as environmental biotechnology for the nitrification and denitrification of wastewater, denitrification of drinking water, anaerobic digestion, production of cell mass and primary and secondary metabolites with microorganisms, and cultivation of animal cell lines. Cell mass and alcohol, glutathion, and enzyme production in gas/solid fluidized beds are also considered. The performance and modelling of these reactors are discussed.
Minimum fluidization velocity of binary mixtures
Authors: Chyang Chien‐Song , Kuo Chen‐Chung , Chen May‐Yann
Published: March 2009

The fast defluidization method was used to measure the minimum fluidization velocities of binary systems. Based on the experimental data obtained from the published literature and from this work, different correlations used for predicting the minimum fluidization velocities of binary systems were evaluated and compared.
The imaginary planes method for the calculation of radiative heat transfer in industrial furnaces
Authors: Charette A. , Erchiqui F. , Kocaefe Y. S.
Published: March 2009

Radiation is usually the dominant mode of heat transfer in furnace enclosures. The imaginary planes method is one of the new methods for calculating the radiative heat transfer in such systems. In this study, a general procedure was developed for its application in furnace modelling. Various case studies were carried out for a number of furnaces, and the results were compared with those of the zone method. It was found that the new method combines good accuracy with low computation time and appears to be a promising method for the determination of heat flux and temperature distributions within furnace enclosures.
Phase equilibrium in the system water‐hydrogen sulphide: Experimental determination of the LLV locus
Authors: Carroll John J. , Mather Alan E.
Published: March 2009

Experimental data are presented for the liquid‐liquid‐vapour (LLV) equilibrium for the system water‐hydrogen sulphide. Conditions ranged from the hydrate‐liquid‐liquid‐vapour quadruple point (29.4°C and 2.23 MPa) to beyond the critical temperature of hydrogen sulphide (100.3°C). The maximum temperature at which three phases can exist is 106.2°C at 9.39 MPa. This is 6°C higher than previously believed.
The structure‐breaking effect on oxygen diffusion coefficients in electrolyte and polyelectrolyte solutions
Authors: Ju Lu‐Kwang , Ho Chester S.
Published: March 2009

By employing a membrane‐covered polarographic oxygen electrode, the oxygen diffusion coefficients and solubilities in aqueous solutions of ammonium chloride, potassium iodide, sodium alginate, sodium carboxymethylcellulose (CMC), and xanthan gum have been measured with a newly developed methodology. Experimental results showed that in all systems studied, oxygen solubilities decrease on addition of solutes. Oxygen diffusion coefficients in aqueous solutions of KI and NH4C1 are found to be higher than that in pure water. In sodium alginate solutions, dilute xanthan solutions, and solutions containing more than 0.3 wt% of CMC, oxygen diffusion coefficients decrease with an increase in polymer concentrations. Interestingly, in dilute CMC solutions and concentrated xanthan solutions containing more than 0.5 wt% of xanthan gum, oxygen diffusion coefficients increase with increasing polymer concentrations, and values exceeding that in pure water are generally observed.
Mass transfer from cylindrical pellets submerged in parallel flowing fluid streams
Authors: Narayan K. A. , Prasad B. K. , Sharma R. N.
Published: March 2009

A model is proposed wherein overall mass transfer from single cylinders of benzoic acid placed in parallel flowing water streams depends on different hydrodynamic regimes prevailing along the surfaces of the cylinder. The results for laminar and turbulent conditions are correlated in terms of Sherwood and Reynolds numbers. The mass transfer in the wake region of the cylinder is observed to be significantly different from the boundary layer mass transfer through the lateral surface or the stagnation and boundary layer mass transfer through the leading frontal area.
Determination of potash crystallization kinetics in a laboratory‐scale continuous cooling crystallizer
Authors: Paine K. , Rohani S.
Published: March 2009

Crystallization kinetics of KCl in a 21.8L continuous mixed‐suspension‐mixed‐product‐removal (CMSMPR) potash cooling crystallizer are determined using the method of s‐plane analysis (Tavare, 1986). Feed saturated in refined potash, nearly saturated in NaCl and containing 0.75 g of MgSO4 per 100 g of water is cooled from 54°C to 38°C by two concentric cooling coils. The crystallizer is brought to steady‐state and then perturbed by a change in the crysallizer temperature from 38°C to 32°C. Samples are withdrawn every 15 minutes by means of a specially devised sample trap which permits representative sample removal. Samples are sized using sieve‐analysis. The crystallization kinetics are correlated as B° = 49,618 G0,982.
Application of periodic operation to maleic anhydride production
Authors: Lang Xiaosu , Hudgins R. R. , Silveston P. L.
Published: March 2009

Two‐step and multi‐step feed composition cycling of the partial oxidation of butadiene to maleic anhydride have been studied. Multi‐step cycles were created by N2 flushes between steps containing just one reactant. Both production and selectivity to maleic anhydride are decreased over a cycle in this type of periodic operation. Selectivity to furan is increased, however. N2 flushing concentrates production of maleic anhydride in the butadiene step, which may have process advantages.
Thermal stability of morpholine additive in the steam‐water cycle of CANDU‐PHW nuclear power plants
Authors: Gilbert Roland , Lamarre Claude
Published: March 2009

The thermal decomposition of morpholine, an additive used in the steam‐water cycles of nuclear power plants, was studied using a laboratory high‐pressure reactor. The measured decomposition rate constants are 2.67, 8.73 and 21.25 × 10−7s−1at 260, 280 and 300°C respectively. The kinetics were found to be first‐order and the activation energy was 131.9 kJ/mol. Ammonia, ethanolamine, 2‐(2‐aminoethoxy) ethanol, methylamine, ethylamine, ethylene glycol, and acetic and glycolic acids were identified as the major breakdown products. The decomposition route proposed was validated in the field by tracking these breakdown products in water samples taken at Gentilly 2 power plant.
Hydrodynamic studies with foaming and non‐newtonian solutions in bubble columns
Authors: Bukur Dragomir B. , Patel Snehal A.
Published: March 2009

Experiments were conducted in 0.05 m ID and 0.23 m ID by 3 m tall bubble columns to study the effect of surfactants and viscosity of liquid medium on gas hold‐up and Sauter mean bubble diameter. The addition of n‐butanol (0.5 and 1 wt.%) to water leads to the formation of foam and consequently produces higher gas hold‐ups. The foam could be eliminated completely with the addition of a sufficient quantity (0.5 wt.%) of carboxymethyl cellulose to the aqueous alcohol solution. In the absence of foam, gas hold‐ups were similar to those obtained with pure liquids. Sauter mean bubble diameters, obtained using the dynamic gas disengagement technique, increase with viscosity of liquid medium.
Effect of interfacial velocity and interfacial tension gradient on momentum, heat and mass transfer
Authors: Hirata Akira , Kawakami Madoka , Okano Yasunori
Published: March 2009

The effect of interfacial velocity and interfacial tension gradient on momentum, heat and mass transfer was studied theoretically. After reviewing current knowledge regarding interfacial velocity effects, the interfacial tension gradient effect is discussed as a numerical solution of the laminar boundary layer equations. The enhancement and suppression of interfacial mobility, and the rates of interphase momentum, heat and mass transfer were related to the Marangoni number. A diagram showing the effect of interfacial tension gradient on momentum, heat and mass transfer is presented.
An adaptive strategy for solving kinetic model concomitant estimation — Reduction problems
Authors: Maria Gheorghe
Published: March 2009

In order to simultaneously estimate the parameters and to reduce a complex kinetic model, an adaptive strategy which combines effective adaptive random search (ARS) and statistical ridge analysis steps is developed. As demonstrated, this strategy can save computational time because the estimation is not repeated with each reduced model. The use of ARS is preferred for highly nonlinear models and cases having multiple parameter constraints, guaranteeing reliability for interactively obtaining the global reduced model parameter solution.
Interfacial viscosity and the stability of emulsions
Authors: Campanelli John R. , Cooper David G.
Published: March 2009

A viscous traction interfacial viscometer was constructed to study a mineral oil‐water‐emulsifier system. The effect on interfacial viscosity of the synthetic emulsifiers Span 80 and Pluronic L42 were investigated, along with the bioemulsifier produced by the yeast Torulopsis petrophilum. In the case of the synthetic emulsifiers, it was found that conditions which maximized interfacial viscosity also maximized emulsion stability. The same relation held for T. petrophilum emulsifier once all free fatty acids had been removed from the broth. Emulsion stability was measured by calculating mean diameters, as well as emulsion indices.
Mixing indices in coflowing plane jets: High momentum conditions
Authors: Ng S. , Grandmaison E. W.
Published: March 2009

Mixing indices describing the completeness of mixing between pairs of plane jets in a triple coflowing jet array have been measured using marker nephelometry. This work is an extension of the results reported by Grandmaison and Zettler (1989) for the case where the centre jet in the array has a higher velocity than the adjacent outer jets. Results include centreline measurements of the static pressure, mean velocity and mean and fluctuation concentration fields, as well as transverse measurements of these properties and concentration intermittency in the near field region where there is significant mixing between the jet streams.
Analysis of an RF induction plasma torch with a permeable ceramic wall
Authors: Mostaghimi Javad , Dostie Michel , Jurewicz Jerzy
Published: March 2009

An analysis is made for an rf plasma torch with a permeable ceramic tube as the contaminant tube. The temperature, flow, and electromagnetic fields in the rf torch are obtained along with the argon flow, the gas and matrix temperatures. The results show that about 80% of the plasma radiation losses are trapped by the ceramic wall. For optimum cooling, a wall with variable thickness is proposed. The results also indicate that argon is not a suitable gas for cooling the permeable wall.
Mixing time of liquid in horizontal stirred vessels with multiple impellers
Authors: Ando K. , Obata E. , Ikeda K. , Fukuda T.
Published: March 2009

A method of estimating the mixing time of multiple‐impeller vessels from that of a single‐impeller vessel was proposed. According to the model assumed, the vessel has completely mixed cells separated by impellers, and the exchange flow rate of liquid across two adjacent cells controls the over‐all mixing. The mixing time of multiple‐impeller vessels of various diameters was measured and analyzed on the basis of the model. The range of application of the model was determined experimentally.
Catalytic pyrolysis of almond shells: Influence of temperature and CoCl2 to almond shell ratio
Authors: Font R. , Marcilla A. , Verdú E. , Devesa J.
Published: March 2009

Two different types of equipment were used in this work: an Analytical Flash Pyrolysis Apparatus (AFPA) and a fluidized bed reactor. Using the AFPA a new screening of catalysts impregnated in almond shells has been carried out. Three catalysts — NaOH, MnCl2 and CoCl2 — were selected to study the influence of the impregnated catalyst/almond shell ratio. With MnCl2 and CoCl2, high yields of 2‐furaldehyde were obtained. With CoCl2, the influence of the catalyst/almond shell ratio and the temperature was studied in both types of equipment. The following yields were obtained using the fluidized bed reactor (14.1 g CoCl2/100 g total) within the temperature range 425–610°C: 2‐furaldehyde 6.9–7.2%, acetic acid 5.5–7.2%. Tests have proved that total recovery of the CoCl2 can be achieved.
Recovery of fatty acids by immobilized solvent extraction
Authors: Lav Isaac , Hayward Gordon
Published: March 2009

The use of silicone rubber tubes swollen with solutions of TOPO (trioctyl phosphine oxide) in kerosene as membranes for the recovery of fatty acids from anaerobic digesters was investigated. The flux of acetic and propionic acids was found to increase with the concentration of TOPO when the concentration was low. At very high TOPO concentrations, the flux decreased indicating the existence of an optimum TOPO concentration. The relationship between the flux and concentration of unionized propionic acid did not agree with that expected for pure diffusion. This was due to the reversible reaction between TOPO and propionic acid in the membrane. The flux of propionic acid was measured as a function of time for new membranes and for membranes removed from storage. Rather long times, 70 to 300 hours, were required to achieve steady acid fluxes. This time was required to fully develop the concentration profiles within the membranes.
Unified entry length for newtonian and power–law fluids in laminar pipe flow
Authors: Mehrotra Anil K. , Patience Gregory S.
Published: March 2009

A numerical method based on finite differencing is used for investigating the steady–state entrance region laminar flow of incompressible Newtonian and power–law fluids in a circular pipe. The Solution method is validated by comparing the results for Newtonian fluids with those reported in the literature. For power–law fluids, the entry length results are compared with other approximate solutions in the literature. On the basis of the calculated results, a generalized entry length ξ99 = 0.056 is shown to be valid for the laminar flow at Re > 200 of both Newtonian and power–law fluids with 0.75 < n < 1.5.
Analysis of particle trajectories of small particles in flotation when the particles and bubbles are both charged
Authors: Okada Kenji , Akagi Yasuharu , Kogure Masahiko , Yoshioka Naoya
Published: March 2009

The trajectory of a small particle moving to a bubble surface was analyzed by taking into account the effects of surface charges of the bubble and particle and the short range hydrodynamic interaction near the bubble surface, in a flotation process. The particle trajectories obtained theoretically were in good agreement with those obtained by direct observation. Even if the signs of the surface charges of the bubble and particle were the same, the particle adhered to the bubble surface when the net surface force, that is, the sum of the electrostatic force and the van der Waals force, was attractive. Particle capture efficiency, ηS, per bubble was estimated by trajectory analysis and the flotation efficiency, ηT, was calculated. The values of ηT calculated by the particle trajectory analysis were in reasonable agreement with those obtained experimentally. The dependence of particle diameter on ηT was also examined by the particle trajectory analysis.
Formation of fine magnetite particles by oxidation of aqueous suspensions of ferrous hydroxide
Authors: Sada E. , Kumazawa H. , Cho H.‐M.
Published: March 2009

Fine magnetite particles were prepared by oxidation of aqueous ferrous hydroxide suspensions in a bubble column equipped with an internal concentric draft tube. The oxidation reaction rate could be expressed apparently as zero‐order with respect to the concentration of total ferrous species and first‐order with respect to the concentration of dissolved oxygen. The final particle size generally decreased with increasing reaction rate. The geometric Standard deviation of size‐distribution ranged from 1.20 to 1.35 under the present experimental conditions, and increased with an increase in reaction rate.
Analysis of the lumped and distributed optimal temperature trajectories for packed bed reactors with concentration dependent catalyst deactivation
Authors: Gonzalez‐Velasco Juan R. , Gutierrez‐Ortiz Miguel A. , Gutierrez‐Ortiz Jose I. , Gonzalez‐Marcos Jose A.
Published: March 2009

Algorithms published previously by the authors for solving the problem of spatially uniform and non‐uniform temperature optimal control in tubular fixed bed reactors have been applied to three systems with series catalyst deactivation and different ratios between the activation energies of the main and deactivation reactions. The optimal temperature and conversion trajectories as well as the maximum production obtained have been compared at the same final duration of operation. Systems with slow deactivation obtain maximum production with spatially uniform control, whilst for systems with rapid deactivation the temperature trajectory distributed both in space and time improves the production obtained with lumped control.
A heat transfer relation for swirl flow in a vortex tube
Authors: Lin Sui , Chen Jirui , Vatistas Georgios H.
Published: March 2009

An experimental investigation was made to study the heat transfer behavior of a water‐cooled vortex tube with air as the working medium. The vortex flow was generated by leading the compressed air to enter the vortex tube tangentially. The pressures of the inlet air were 300 to 500 kPa gauge. For each of these inlet pressures, the heat transfer performance of the vortex tube was studied at different cold mass flow ratios. New experimental data are presented. An empirical correlation for the prediction of the air‐side Nusselt number is established. It was shown that the air‐side Nusselt number for the swirl flow in this vortex tube can be up to 30 times higher than that for a flow without swirl in the same tube.
Interfacial area and mass transfer in gas‐liquid cocurrent upflow and countercurrent flow in reciprocating plate column
Authors: Sundaresan A. , Varma Y. B. G.
Published: March 2009

The volumetric mass transfer coefficient and the interfacial area were measured for carbon dioxide absorption into water using a reciprocating plate column of plate geometry different from a Karr column. The specific interfacial area was governed by a change in bubble size at low agitation rates and by a variation in gas holdup at high agitation rates. The liquid phase mass transfer coefficient was strongly influenced by the agitation rate, the phase velocities and the plate geometry.
Oil recovery from oil in water emulsions using a flotation column
Authors: Pal Rajinder , Masliyah Jacob
Published: March 2009

A flotation column was used to recover oil from oil in water emulsions. The feed oil concentrations investigated were relatively high, in the range of 0.25 to 8 percent by volume. Previous studies using conventional flotation cells dealt with very dilute systems where the oil concentration was less than 0.1 percent by volume.

The oil recovery was found to decrease with an increase in the feed oil concentration. The addition of wash water to the froth zone of the column had little effect on the oil recovery. The oil recovery decreased with increasing feed flow rate and surfactant concentration. The effect of increasing the gas flow rate was to initially increase the oil recovery. The oil recovery data were analyzed using a kinetic model. The order of the flotation kinetics was found to be 0.6.

The gas hold‐up behaviour of the recovery and the froth zones of the flotation column is found to correlate well with the drift‐flux model.
The electrochemical oxidation of aqueous phenol at a glassy carbon electrode
Authors: Gattrell M. , Kirk D. W.
Published: March 2009

The electrooxidation of phenol is of interest as a model compound for the treatment of aqueous organic wastes. The effect of voltage, concentration and temperature on the electrochemical oxidation of acidic dilute aqueous solutions of phenol was studied. Electrolysis was carried out by recirculating phenol solutions through a flow‐by electrochemical reactor employing a reticulated glassy carbon anode. Concentrations of phenol and some breakdown products were monitored using HPLC analysis.

Increased voltage was found to shift the product distribution to favour more oxidized products but also to increase electrode corrosion and decrease current efficiency. Higher phenol concentrations (over the range of 5‐20 mmol/L) showed a shift in product distribution to favour less oxidized, mostly insoluble products. Elevated temperatures (about 50°C and higher) showed a marked ability to reduce electrode passivation and increase the phenol oxidation rate.
Henry's law constants and thermodynamic properties of gases and vapours in bitumens
Authors: Xv Yuming , Hepler Loren G.
Published: March 2009

Solubilities for 13 gases and vapours (CO2, alkanes from ethane to n‐octane, benzene, toluene, xylene, dichloromethane, and methanol) in two Alberta bitumens (Athabasca and Wolf Lake) have been measured at several temperatures (30‐150°C), using gas‐liquid chromatography (GLC). The GLC method yields accurate solubilities and Henry's law constants for moderately soluble gases, but is not applicable to less soluble gases such as CH4 and H2. Results have been used for calculations of ΔHo and ΔCop for processes of the type Solute Substance (gas) = Solute Substance (in bitumen).

Correlations of Henry's law constants and ΔHo values with carbon number for alkanes have been observed and used for predictions of CH4 solubilities in bitumens.
A generalized correlation for the prediction of phase behaviour in supercritical systems
Authors: Trebble M. A. , Sigmund P. M.
Published: March 2009

A generalized two parameter model is presented which uses molecular properties of pure fluids to predict interaction parameters in the attractive term of the Peng‐Robinson equation of state. The predictive method is based on a consideration of London (dispersive) forces and includes attractive forces between polar and non‐polar molecules that result from induction. Polar‐polar effects and quantum forces are omitted. A large body of experimental vapor‐liquid equilibrium data measured at near and supercritical conditions (that excludes quantum components and polar‐polar systems) was used to calibrate the generalized model. Overall bubble point pressure deviations calculated using the proposed generalization were 5.66% for 3240 data points which compares to average deviations of 3.27% obtained by using regressed binary interaction parameters. Average vapor mole fraction deviations were just under 0.01 using both the generalized and the regressed interaction parameters. The sensitivity of predicted phase envelopes to dispersive and inductive term in the generalized correlation is shown graphically for several systems. Comparisons are also made to another recent interaction parameter generalization presented by Nishiumi et al. (1988).
Multivariate statistical monitoring of process operating performance
Authors: Kresta James V. , Macgregor John F. , Marlin Thomas E.
Published: March 2009

Process computers routinely collect hundreds to thousands of pieces of data from a multitude of plant sensors every few seconds. This has caused a “data overload” and due to the lack of appropriate analyses very little is currently being done to utilize this wealth of information. Operating personnel typically use only a few variables to monitor the plant's performance. However, multivariate statistical methods such as PLS (Partial Least Squares or Projection to Latent Structures) and PCA (Principal Component Analysis) are capable of compressing the information down into low dimensional spaces which retain most of the information. Using this method of statistical data compression a multivariate monitoring procedure analogous to the univariate Shewart Chart has been developed to efficiently monitor the performance of large processes, and to rapidly detect and identify important process changes. This procedure is demonstrated using simulations of two processes, a fluidized bed reactor and an extractive distillation column.
An expert system for identifying separation processes
Authors: Garg Mahesh K. , Linders James G. , Douglas Peter L.
Published: March 2009

This paper presents the development of an expert system, called SIS (Separator Identification System), to generate near‐optimal separation sequences for any multicomponent mixture. SIS was designed based on a combination of heuristic and algorithmic approaches. Heuristics were used to select the location of the split. Algorithms were used to calculate physical properties of the multicomponent mixture. A fuzzy approach was used for the propagation of the truth function and uncertainty management. SIS was tested using four sample problems involving gas, liquid, and solid components. The separation sequences suggested by SIS were the same or similar to those found in process synthesis literature.
Extrudate swell of newtonian liquids from rectangular dies
Authors: Esmail M. N.
Published: March 2009

Extrudate swell from square and rectangular dies was studied for glycerol solutions. Experiments were performed for a wide range of viscosities 75 < μ < 464 mPa · s, with small changes in surface tension and density. Dies with aspect ratios of 3:1 and 2.25:1 and a wide range of length to hydraulic diameter ratios, i.e., 24 < l/Dh < 62, were used. Results were obtained in the range of Reynolds number 1 < Re < 50. Swell ratios for the short and long faces of a die are below the swell ratio of a plane slit. Swell ratios for the short face are consistently higher than those for the long face for lower Reynolds numbers. Liquid contracted at the corners, while swelling along faces.