bluuebunny/crossref_metadata_2025_split huggingface dataset:
The particle collection efficiency of a cascade of cylinders
Authors: Ingham D. B. , Hildyard M. L. , Heggs P. J. 
Published: March 2009

AbstractThe entry flow and the trajectories of small solid particles into a fibrous filter, which is modelled as a single row or cascade of cylinders, is examined. Both large (potential) and small (creeping) Reynolds number flows through the cascade of cylinders are treated using the Boundary Element Method (BEM). Results for the collection efficiency are presented as functions of the Stokes number for both types of flow and are shown to be in excellent agreement with existing published results. An asymptotic expansion of the flow is developed both upstream and downstream of the cascade and it is shown to significantly affect the collection efficiency.
Improvement in separation of the batch‐type thermal diffusion column with impermeable barriers inserted between the plates
Authors: Weitsai Shau , Yeh Ho‐Ming 
Published: March 2009

AbstractRather than one impermeable barrier, the installation of more impermeable barriers between the plates in a batch‐type thermal diffusion column substantially enhances the separation efficiency by further properly reducing the remixing effect. Theoretical analysis shows that when the barriers are installed at the best positions, maximum degree of separation, maximum concentration of the top product or minimum concentration of the bottom product may be obtained. Considerable improvement is obtained especially when the ratio K'; of transport constants (i.e. Kc/Kd) is large.
Recovery of copper from copper concentrator tailings by leaching
Authors: Acharjee D. K. 
Published: March 2009

AbstractTailings from a chalcopyrite beneficiation plant (concentrator) have been leached with dilute ferric chloride in a packed bed. The effect of leaching time and packed bed height on the conversion of cuprous sulphide (present in tailings) has been determined. For predicting the conversion, an expression based on the shrinking core model has been derived and compared with the experimental data. At low conversion, the agreement is good, but at intermediate and high conversion the deviation is considerable.
Dissolution of spherical solid particles in a stagnant fluid: An analytical solution
Authors: Chen Yu‐Wen , Wang Pei‐Jan 
Published: March 2009

AbstractFilm theory has often been used to calculate the dissolution rates of solid particles. However, it is only good for the case of low solubility solids due to the assumption of pseudo‐steady state. In this study, we propose a more refined model to facilitate the characterization of the dissolution of spherical solid particles in a stagnant fluid. The results indicate that the film theory will overestimate the dissolution time for the case of high solubility, while for low solubility particles, the film theory is quite accurate in predicting the dissolution time.
The effects of clay fines on oil in water dispersions
Authors: Spence J. R. , Masliyah J. H. 
Published: March 2009

AbstractThe effects of the addition of clay on oil drop size were investigated for dispersions of oil in water in an agitated vessel. Three types of oil were used: hexane, a medium viscosity paraffin oil and a viscous Cold Lake bitumen. Pure kaolinite clay was used for the solids. Experiments were carried out with and without clay fines over a range of agitator speeds. The addition of kaolinite was found to increase the drop size for both the hexane and the paraffin oil, approximately doubling the drop size for hexane. The addition of the kaolinite to the bitumen/water dispersions was found to have no effect on the drop size.
Experimental study of an extruder‐feeder for biomass direct liquefaction
Authors: White D. H. , Schott N. R. , Wolf D. 
Published: March 2009

AbstractA new type of feeding system by an extruder‐feeder was utilized to pump high concentrations of slurries into an advanced biomass liquefaction reactor operating at pressures of up to 25 MPa and temperatures of up to 400°C. The operability of such an extruder‐feeder and the design criteria for this type of unit operation are described, and operational data are reported. Three types of extruder‐feeders were used, and many different types of feedstocks were tested. The extruder‐feeder proved to be effective in the biomass direct liquefaction process and could prove applicable in many other processes where high concentrations of solids are to be pumped, thus reducing drastically the size of the plant and the need for recycle of large amounts of liquid carriers for the solids.Typical experimental data and results of the flow rates and pressure generation for the various extruder‐feeders and their operational conditions for several feedstocks are reported. The theoretical models developed for plasticating extruders were found to be acceptable also for the extruder‐feeder of biomass feedstock, applying appropriate drag and pressure flow coefficients.
The Adsorption of p‐nitrophenol on anion exchange resin at various temperatures
Authors: Huang Ting‐Chia , Cho Lan‐T'Ai 
Published: March 2009

AbstractThe isotherms of p‐nitrophenol adsorbed on the anion exchange resin Ionac AFP‐329 at temperatures in the range of 278.1 to 338.1 K are correlated with the Freundlich equation. The temperature dependences of the Freundlich constants and the effect of the amount adsorbed on the isosteric heat of adsorption are discussed. The results indicate that the relationships between k, n and temperature can be expressed as.n = 0.00129 Tln k = 5.12 – 0.0152 Tandln k = 5.05 – 11.63 nand that the isosteric heat of adsorption varies linearly with the logarithm of amount adsorbed.
Rotary cylinders: Solid transport prediction by dimensional and rheological analysis
Authors: Perron J. , Bui R. T. 
Published: March 2009

AbstractA semi‐experimental model for predicting the axial transport of the granular bed in a rotating cylinder is proposed. It is based on dimensional analysis and on the determination of an apparent viscosity characterizing the flow behaviour of the bed. Unknown constants in the model are determined either by analysis or by tuning with experimental data. An example of such tuning is shown to work well. The model is capable of giving, as a function of filling angle and friction angle, the axial velocity that varies along the cylinder axis. This is important for the control of the process taking place inside the cylinder.
Synthese du furyl‐2 oxiranne en milieu hétérogène solide‐liquide faiblement hydrate: Determination du régime de production, expression de la loi cinétique
Authors: Rakotondramanana Samuel , Borredon Elisabeth , Molinier Jacques 
Published: March 2009

AbstractAfin d'étudier le transfert à plus grande échelle de la synthèse du furyl‐2 oxiranne à partir du furfural, les conditions opératoires les mieux adaptées ont été définies. Le domaine expérimental étant déterminé, l'utilisation d'une cuve agitée à alimentation et soutirage continus s'est avérée être la plus performante. Enfin, l'expression de la loi cinétique de la réaction d'époxydation a permis d'évaluer la production horaire en époxyde.
High yield production of microcrystalline cellulose by a thermo‐mechano‐solvolytic treatment
Authors: Garnier G. , Bouchard J. , Overend R. P. , Chornet E. , Vidal P. F. 
Published: March 2009

AbstractBy thermally treating a commercial cellulose in ethylene glycol, celluloses of controlled low degree of polymerization, DPr = 1000 to 70, can be derived. Two general behaviors are observed in the range studied. At first, the depolymerization reaction is predominant down to a DP equal to 130. Beyond this level, the depolymerization process leads to extensive solubilization of the cellulose. The treated celluloses have been analyzed by X‐ray diffraction, FTIR, TGA, elemental analysis and enzymatic hydrolysis. No chemical change of the cellulose could explain the two different behaviors. A physical modification in the form of depolymerization and destructuration is suspected.
Dynamics of adsorptive reactors I — Instantaneous nonlinear adsorption and finite zero order irreversible reaction
Authors: Loureiro José , Costa Carlos , Rodrigues Alírio 
Published: March 2009

AbstractThe dynamics of adsorptive reactors, in which the coupling of nonlinear Langmuir adsorption with zero order reaction A → B occurs, is considered. The method of characteristics is used to develop, analytically, the responses of fixed bed (plug flow) adsorber/reactors to step, pulse or Dirac inputs of reactant A. An increase in the breakthrough time of the column is observed as a consequence of the coupling of both phenomena.The responses of CSTR adsorber/reactors to step or Dirac inputs of reactant A are derived, as well. A method for the determination of equilibrium and kinetic parameters is proposed.
Set‐point optimization of an adiabatic trickle‐bed reactor system
Authors: Chao Yung‐Cheng , Chang Jyh‐Shyong , Huang Hsiao‐Ping 
Published: March 2009

AbstractA combined system parameter estimation and deactivation model identification procedure is proposed to create a grey model of an adiabatic residue hydrodesulfurization (RDS) trickle‐bed reactor. Using the resulting grey model, a precomputed set‐point table is used to optimize the set‐point of the RDS reactor unit. The objective function chosen is the predetermined reactor outlet sulfur content and the optimal set‐point is the reactor inlet temperature. Five crucial case studies using a dynamic simulator of an adiabatic RDS trickle‐bed reactor demonstrate the applicability of the proposed algorithm in developing optimal set‐points for a commercial process.
Porous gas distributors in bubble columns. Effect of liquid presence on distributor pressure drop. Effect of start‐up procedure on distributor performance
Authors: Prakash A. , Briens C. L. 
Published: March 2009

AbstractMany bubble columns use porous gas distributors to obtain small bubbles and large mass transfer rates. The distributor pressure drop contributes greatly to the energy consumption of bubble columns. This study found that the presence of liquid increased this pressure drop by 200 to 900% at practical gas flowrates. A model was developed to predict this increase. It assumes that gas flows through a fraction only of the pores so as to minimize the distributor pressure drop.The mass transfer performance of a porous distributor is affected by its startup procedure. The best performance was obtained by starting the gas flow before liquid was introduced into the column. A model was developed to explain these results.
Mass transfer in a trickle‐bed column packed with a mixture of hydrophobic and hydrophilic spheres
Authors: Rangwala H. A. , Otto F. D. , Wanke S. E. , Chuang K. T. 
Published: March 2009

AbstractRates of mass transfer have been measured in a trickle‐bed column packed with a mixture of hydrophobic and hydrophilic spheres. The results show that the interfacial area is a strong function of bed composition and liquid flow rates. The gas‐phase mass transfer coefficients are not affected by the nature of the bed and agree well with values predicted by the correlations available in the literature. The dynamic liquid hold‐up in a bed of hydrophilic spheres was found to be four to seven times higher than that in a bed of hydrophobic spheres.
Hydrolysis of carbonyl sulfide: Comparison to reactions of isocyanates
Authors: Ernst Wiliam R. , Chen Michael S. K. , Mitchell David L. 
Published: March 2009

AbstractThe hydrolysis of carbonyl suflfide (COS), catalyzed by tertiary amines, was studied in a gas‐liquid reactor at ambient conditions. Rate constants determined in a batch reactor were similar to those determined in a continuous flow reactor. A Bronsted plot of the reaction data over the amine basicity range, 0 < pKB < 14, suggested that both amine basicity and steric factors determine catalytic behavior. The reaction data suggest a mechanism analogous to one used to explain the base catalyzed reaction of isocyanates with hydroxyl compounds. The mechanism would involve complexation of COS with amine followed by hydrolysis of the complex.
Gas‐Liquid mass transfer in a three‐phase fluidized bed with floating bubble breakers
Authors: Kim Jong O. , Kim Sang D. 
Published: March 2009

AbstractThe effects of liquid and gas velocities, particle size and volume ratio of floating bubble breakers to solid particles (Vf/Vs) on both the volumetric mass transfer coefficient, kla, and the gas‐liquid interfacial area, a, have been determined in three‐phase fluidized beds with floating bubble breakers. Beds having a volume ratio (Vf/Vs) of about 0.15 showed a maximum increase in both kla and a of about 30% in comparison to that in the corresponding bed without floating bubble breakers. The volumetric mass transfer coefficient in three‐phase fluidized beds with or without floating bubble breakers can be estimated from the surface renewal frequency of liquid microeddies and the particle size.
In‐situ cleaning of packings in water distillation column with a surfactant
Authors: Chuang K. T. , Sutherland R. P. 
Published: March 2009

AbstractA novel method for the in‐situ cleaning of fouled packing by injecting a suitable surfactant into a water distillation column has been examined. Experiments were carried out to determine the effectiveness of such a surfactant. Test data indicate that the injection of a low foaming non‐volatile surfactant, Triton CF‐32, in the feed water results in a significant improvement in the efficiency of a contaminated packing. It was found that the packing can be restored to its new conditions if the injection is maintained for a sufficient period of time. The surfactant can be easily removed from the bottoms product either by evaporation of the heavy water or carbon adsorption of the surfactant.
Preparation of hemolysate‐filled hexamethylene sebacamide microcapsules with controlled diameter
Authors: De Smet B. Poncelet , Neufeld R. J. , Poncelet D. 
Published: March 2009

AbstractHemolysate‐filled hexamethylene sebacamide microcapsules (nylon‐6, 10 membranes) were prepared by interfacial polymerization. Sheet lattice, frame lattice, turbine and marine impellers were tested to control the microcapsule mean diameter and size distribution parameters. Mean diameters ranging from 40 to 200 μm were obtained depending on the impeller type, rotational speed and emulsifier concentration. The size dispersion of microcapsule preparations was best controlled with a frame lattice impeller, achieving standard deviation values less than 40% of the mean diameter. The wire diameter and mesh dimensions of the impeller lattice had little effect on the distribution parameters.
Reaction of thiophene on CoMo/A12O3 catalysts of various loading at low hydrogen excess
Authors: Manninger I. , Paál Z. , Henze K. P. , De Joung G. 
Published: March 2009

AbstractCo‐Mo/Al203 catalysts of various CoMo loadings were examined in the hydrodesulfurization (HDS) reaction of thiophene and tetrahydrothiophene at near stochiometric hydrogen: thiophene ratio. Good compensation plots were found for both reagents and all catalysts. Reversibly bound H2S blocks active sites of HDS. The most important reaction pathway leads to but‐1‐ene; more Co gives more but‐2‐ene. The hydrogenation of buta‐1, 3‐diene is about 100 times more rapid than that of but‐1‐ene. The activity of two neighboring sites with twofold coordinative unsaturation is suggested in buta‐1, 3‐diene hydrogenation. The possible effect of Al203 support on active sites is discussed.
Slurry filtrability of potash alum
Authors: Jones A. G. , Mydlarz J. 
Published: March 2009

AbstractCrystal slurries produced both by cooling and by precipitation with acetone from aqueous solution in a continuous MSMPR crystallizer reported earlier (Jones and Mydlarz, 1990) are analysed in terms of the effect of their crystal size distribution and shape on filtrability characteristics.Crystals produced by precipitation are much smaller but more highly agglomerated than those from cooling crystallization and give rise to lower filter bed permeabilities, a performance which is slightly improved by precipitant dilution. The overall particle size is, however, similar in both modes and is relatively insensitive to crystallizer operating conditions. The filtrability data for the precipitated crystals are compared with predictions of the Carman‐Kozeny equation, assuming an idealized crystal shape. Relatively large scatter is observed, with the Kozeny coefficient, K, being in the range 2 to 8.
Catalytic upgrading of liquid hydrocarbons derived from coprocessing of heavy oil and coal
Authors: George Zacheria Mathew 
Published: March 2009

AbstractCoprocessing of heavy oil and coal under elevated temperature, hydrogen pressure and low space velocity resulted in a product slurry from which the fraction distilling below 430° C was catalytically upgraded over a commercial NiMo/Al2O3 catalyst in a flow reactor. At 400° C, 13.3 MPa (H2) and LHSV of 1.0 h−1 over 90% of sulfur and nitrogen could be removed, aromaticity reduced to 16% from 26% and the API gravity increased to 36.9 from 23.8. Hydrogen consumption under these conditions was considerably lower than that obtained for upgrading the oil sands coker gas oil. Activation energies for hydrodesulfurization and hydrodenitrogenation reactions were determined to be 59.5 and 120.4 kJ/mol, respectively.
Modelling of equilibrium solubility of CO2 and H2S in aqueous diglycolamine (DGA) solutions
Authors: Hu W. , Chakma A. 
Published: March 2009

AbstractInformation on acid gas solubility in solvents utilized is needed for the design of gas plants. A mathematical model for the prediction of equilibrium solubility of CO2 and H2S in aqueous 2‐amino‐2‐(ethoxy)ethanol (DGA) solutions is presented. The equilibrium constants, K1 and K2, representing a simple proton transfer reaction and the carbamate formation reaction, respectively, were found to be functions of temperature and free acid gas concentration. In addition, K2, was affected by DGA concentration as well. Model predictions agree favourably with experimental data.
An impinging–Streams reactor with two pairs of tangential air feeds
Authors: Bar Tami , Tamir Abraham 
Published: March 2009

AbstractThe original two–impinging steams devices have proved useful for processes in gas–solid Systems. A modified form of the original two–impinging–streams reactor, with two additional air streams, was explored. All four air streams are fed tangentially to the reactor. The Performance characteristics included the determination of the pressure drop on the reactor, limits of the gas and solid particle mass flow rate, the mean residence time of the particles, and the drying heat transfer, as a function of air flow rates of the secondary and major air streams.The behaviour of the particles and their residence time distribution was investigated by applying a stochastic Markov chain model.It was found that the secondary air stream increases the pressure drop on the reactor and the mean residence time of the particles along with their recycling in the reactor. On the other hand, the secondary air stream decreases the critical mass flow rate of the particles, delays their exit from the reactor and reduces the heat transfer coefficient in drying wet particles.
Drop size distribution in a graesser contactor
Authors: Al‐;Hemiri A. A. , Kareem A. 
Published: March 2009

AbstractAn investigation was conducted of drop size distribution in a Graesser contactor, employing five liquid – liquid systems, viz., kerosene/water, benzene/water, xylene/water, hexane/water and n–butyl acetate/water. A 100 mm (4 inch) diameter Graesser contactor was used for this purposeIt was found that the drop size distribution in a Graesser contactor obeys the upper – limit distribution expressed as:

where

A correlation was developed relating the Sauter mean diameter (d32) to other effective groups
A correlation for predicting diffusion coefficients in alkanes
Authors: Erkey C. , Rodden J. B. , Akgerman A. 
Published: March 2009

AbstractA correlation was developed for predicting limiting mutual diffusion coefficients of gaseous and liquid solutes in normal alkane solvents with carbon numbers ranging from 7 to 28 at temperatures to 570 K. The functional form of the correlation is based on the rough hard sphere theory. The parameters needed in the correlation are the molecular weights and hard sphere diameters of the solute and solvent molecules and molar volume of the solvent. The data used in the development of the correlation included 143 measurements with solute/solvent molecular mass ratios ranging from 0.005 to 2.26 and size ratios ranging from 0.3 to 1.3. The average absolute error in predictions was only 6.3%. When the correlation was used to predict literature values for binary n‐alkane systems, the average absolute error was 16.7%.
New measures for robustness in linear multivariable feedback systems
Authors: Alatiqi Imad M. 
Published: March 2009

AbstractNew measures for robustness are proposed for linear multivariable control systems. A new theorem is presented to account for the controllability of systems that contain an integrating element, in the presence of additive uncertainties. The theorem leads to the definition of a sufficient condition for robust integral controllability: robustness margin (RM). The ratio of robustness margins for competing control or processs structures can be used to discriminate between these structures. These measures are useful, especially in design stages, since their calculation depends only on steady state information. Applications to several published distillation systems show the merits of these robustness measures.
Performance of a tubular elastic sparger
Authors: Weber M. E. , Loiselle E. , Charrier J.‐M. 
Published: March 2009

AbstractElastic spargers were made from natural latex rubber tubes by repeatedly piercing the tube wall with a lance‐shaped needle to make multiple, axially‐aligned, slit‐like punctures. Gas holdups, volumetric mass transfer coefficients and pressure drops were measured at several gas flowrates for single elastic spargers oriented vertically in a column of liquid, and compared with the corresponding measurements for a rigid sparger.
Flow transition for natural convective heat transfer in a porous medium saturated with water near 4°C
Authors: Islam M. R. , Chakma A. , Nandakumar K. 
Published: March 2009

AbstractIn this paper, the problem of buoyancy‐induced convection flow in water‐saturated porous media near 4°C is examined using a numerical model. Darcy's law is used to model flow behavior and a single equation convective heat transfer model is used for the energy equation. As the Boussinesq approximation is not valid for this case, a parabolic dependence of density on the temperature is used. Natural convection is generated and sustained by a uniform heat source. Flow behavior is governed by three natural parameters appearing in the model. They are: (i) dynamical parameter,

(ii) geometric parameter, γ = b/a; and (iii) wall temperature,

in relation to the reference temperature at the density extremum.For certain ranges of θw (<0) and Gr, interesting density inversion effects are possible. Transient solutions are obtained for various aspect ratios and modified Grashof number values. For a wide range of Grashof number, steady state solutions could not be obtained. Flow mutations into periodic and chaotic solutions are investigated for a range of Grashof number (100 to 40,000) and aspect ratio values (1 to 10).
A simple model for a non‐isothermal adsorption column
Authors: Ruthven Douglas M. , Rojo J. Carlos 
Published: March 2009

AbstractA simple analytic solution has been derived for the temperature response of a non‐isothermal adsorption column in which a small concentration of an irreversibly adsorbed species is removed. The model is shown to provide a reasonable representation of the experimentally observed behaviour of an ethanol drying column using 3A molecular sieve as the moisture selective adsorbent.