Catalogue en ligne Bibliothèque Ecole Nationale Polytechnique d'Alger

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2290–2296

Titre :	In silico prediction of molecular volumes, heat capacities, and temperature-dependent densities of ionic liquids
Type de document :	texte imprimé
Auteurs :	Ulrich P. R. M. Preiss, Auteur ; John M. Slattery, Auteur ; Ingo Krossing, Auteur
Année de publication :	2009
Article en page(s) :	p. 2290–2296
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Heat capacities Temperature-dependent density Ionic liquids
Résumé :	We present a fast and reliable general estimation of the heat capacity, Cp, and temperature-dependent density, ρ, of ionic liquids, based on a new in silico method to calculate the molecular volume, Vm. The knowledge of Vm allows the prediction of many physical properties of hitherto unknown ionic liquids as well as the prediction of lattice energies and entropies of salts.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801268a

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2283–2289

Titre :	A note on the controllability of two short-cut designs for a class of thermally coupled distillation sequence
Type de document :	texte imprimé
Auteurs :	Miguel Vaca, Auteur ; Arturo Jimenez-Gutierrez, Auteur ; José Alvarez-Ramírez, Auteur
Année de publication :	2009
Article en page(s) :	p. 2283–2289
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Ternary mixtures Thermally coupled sequence Open-loop transfer function
Résumé :	The separation of multicomponent mixtures with conventional distillation sequences is energy-intensive. The use of thermal coupling sequences provides a more-efficient alternative, although their industrial usage has been quite limited, because of the complexity of design methods and potential difficulties during operation. In this work, we study a direct thermally coupled sequence for the separation of ideal ternary mixtures and perform a comparative study of two different designs, one based on the tray structure of an equivalent conventional sequence and the other specifically considering the effect of the thermal coupling on tray distribution and operational flows. Using the singular value decomposition technique on open-loop transfer function matrixes, controllability indexes were obtained. The controllability indexes of both designs are of the same order of magnitude, which means that their dynamic responses are basically the same. Although additional studies of dynamic simulation under closed-loop conditions are necessary, our results indicate that the controllability properties are similar, and that the design that provides the smallest energy consumption should be favored.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800993u

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2275–2282

Titre :	Electrochemical reactions for electrocoagulation using iron electrodes
Type de document :	texte imprimé
Auteurs :	Hector A. Moreno C., Auteur ; David L. Cocke, Auteur ; Jewel A. G. Gomes, Auteur
Année de publication :	2009
Article en page(s) :	p. 2275–2282
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Electrocoagulation Wastewater treatment Iron electrodes
Résumé :	Electrocoagulation (EC) has been known for more than a century. Applications in industries such as water and wastewater treatment processes have been adapted for the removal of metals, nonmetals, suspended solids, organic compounds, COD (chemical oxygen demand), and BOD (biological oxygen demand). Iron electrodes have been preferred over aluminum due to their durability and cost. However, the electrochemical reactions occurring with EC using iron electrodes have not been systematically studied. For a better understanding of the mechanism and reactions for EC using iron electrodes, we present a review of the concept of green rust (GR) and its relationship to the current theory of EC. Experimental results obtained by measuring pH at different zones near the iron electrodes during the EC process are detailed, and are used to illustrate the mechanism and reactions that occur at both the anode and the cathode. The mechanism and reactions presented explain phenomena associated with EC and are congruent with solubility and Pourbaix diagrams.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8013007

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2266–2274

Titre :	Solid particle mobility in agitated bingham liquids
Type de document :	texte imprimé
Auteurs :	J. J. Derksen, Auteur
Année de publication :	2009
Article en page(s) :	p. 2266–2274
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Combined flow Yield-stress liquids Mixing tank Lattice-Boltzmann scheme
Résumé :	Motivated by applications in oil sands processing, numerical simulations of the combined flow of yield-stress (Bingham) liquids and solid particles in a mixing tank have been performed. The conditions were such that, generally, the flow systems were in a transitional regime, between laminar and developed turbulence. The fluid flow was simulated according to a lattice-Boltzmann scheme, with the yield stress being mimicked as a highly viscous fluid for low deformation rates. Particles were assumed to move under the influence of drag, gravity, and particle−wall and particle−particle collisions. Agitation formed a cavity (active volume) around the impeller, with the rest of the tank being virtually inactive. This mobilized the particles in the cavity. In their ability to suspend and mobilize particles, agitated Bingham liquids behave markedly different from Newtonian liquids.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801296q

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2266–2274

Titre :	Solid particle mobility in agitated bingham liquids
Type de document :	texte imprimé
Auteurs :	J. J. Derksen, Auteur
Année de publication :	2009
Article en page(s) :	p. 2266–2274
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Combined flow Yield-stress liquids Mixing tank Lattice-Boltzmann scheme
Résumé :	Motivated by applications in oil sands processing, numerical simulations of the combined flow of yield-stress (Bingham) liquids and solid particles in a mixing tank have been performed. The conditions were such that, generally, the flow systems were in a transitional regime, between laminar and developed turbulence. The fluid flow was simulated according to a lattice-Boltzmann scheme, with the yield stress being mimicked as a highly viscous fluid for low deformation rates. Particles were assumed to move under the influence of drag, gravity, and particle−wall and particle−particle collisions. Agitation formed a cavity (active volume) around the impeller, with the rest of the tank being virtually inactive. This mobilized the particles in the cavity. In their ability to suspend and mobilize particles, agitated Bingham liquids behave markedly different from Newtonian liquids.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801296q

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2257–2265

Titre :	Development of an a priori ionic liquid design tool. 2. Ionic liquid selection through the prediction of COSMO-RS molecular descriptor by inverse neural network
Type de document :	texte imprimé
Auteurs :	José Palomar, Auteur ; José S. Torrecilla, Auteur ; Víctor R. Ferro, Auteur
Année de publication :	2009
Article en page(s) :	p. 2257–2265
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Ionic liquids Inverse neural networks Molecular descriptor
Résumé :	In this work, the a priori computational tool for screening ILs, developed in previous part 1, is extended to the simultaneous prediction of a set of IL properties for 45 imidazolium-based ILs. In addition, current part 2 reports the development of a more useful design strategy, which introduces the target IL properties as input, resulting in the selections of counterions as output, that is directly designing ILs on the computer. For this purpose, inverse neural networks are used to estimate the Sσ-profile molecular descriptor of a potential IL solvent by the specification of its required properties, following a reverse quantitative structure−property relationship scheme. Subsequently, a statistical tool based on Euclidean distances is developed to select an adequate set of anion+cation combinations that fulfill the estimated Sσ-profile values, to obtain, in this case, the tailor-made ILs. Finally, the proposed computational tool for designing ILs is applied in liquid−liquid extraction of a system model (toluene/n-heptane). In view of the inherent modular nature of ILs, the proposed methodology is here used in the formulation of IL mixtures to enhance the performance of extractive solvents in the aromatic/aliphatic separation.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8009507

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2245–2256

Titre :	Efficient visual mixture design of experiments using property clustering techniques
Type de document :	texte imprimé
Auteurs :	Charles C. Solvason, Auteur ; Nishanth G. Chemmangattuvalappil, Auteur ; Fadwa T. Eljack, Auteur
Année de publication :	2009
Article en page(s) :	p. 2245–2256
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Mixture design Chemical constituents Clustering techniques
Résumé :	Mixture design is a design of experiments (DOE) tool used to determine the optimum combination of chemical constituents that deliver a desired response (or property) using a minimum number of experimental runs. While the approach is sufficient for most experimental designs, it suffers from combinatorial explosion and visualization difficulties when dealing with multicomponent mixtures. To circumvent these problems, a recently developed design technique called property clustering is applied. In this type of design the properties are transformed to conserved surrogate property clusters described by property operators, which have linear mixing rules even if the operators themselves are nonlinear. Product and process property targets are then used to describe a feasibility target region. To solve the mixture design, components are mixed according to property operator models in a reverse problem format until the mixture falls within the feasibility target region. Once candidate solutions are found, they can be screened with additional criteria per the experimenter’s preference. The degree of accuracy of this modeling technique depends heavily on the ability of the property operator models to adequately describe the property within the studied design space. This work utilizes linear Scheffe and Cox models as property operators of a mixture design to demonstrate the benefits of applying property clustering to chemometric techniques.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800877d

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2236–2244

Titre :	Emissivity of high-temperature fiber composites
Type de document :	texte imprimé
Auteurs :	Xiangning Li, Auteur ; William Strieder, Auteur
Année de publication :	2009
Article en page(s) :	p. 2236–2244
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	High-temperature fiber composites Edge surface
Résumé :	Effective emissivities of high-temperature fiber composites are calculated for several external edge surface structures—randomly overlapping, parallel cylinders of radius a protruding out a distance δ from the composite matrix, with central axes either perpendicular to or into the direction of the composite external edge. First-order multiple scattering reciprocal bounds provide effective emissivity values, usually within an error of 10% or less; e.g., for carbon−carbon composites with a fiber−matrix emissivity of εs = 0.8 and a fiber fraction of 30 vol %, the maximum error bound is 4%−5%. The fundamental behavior of the effective emissivity, as a function of protrusion depth, is examined, and significant deep-bed, blackbody radiative effects are observed, even at modest model protrusions. A maximum value for the fiber composite effective emissivity at an optimum porosity is found for any given ratio of protrusion length to fiber radius (δ/a) and fiber−matrix emissivity (εs); e.g., for a perpendicular protrusion with δ/a = 3 and εs = 0.5, a maximum effective emissivity enhancement of 27% is found at Φ = 0.6, and for fibers protruding parallel to the edge with δ/a = 3 and εs = 0.5, a maximum enhancement of 21% is observed at Φ = 0.6. Model equation results agree with the measured effective emissivity values of carbon−carbon brake composites.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8008583

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2229–2235

Titre :	Estimation of freezing point depression, boiling point elevation, and vaporization enthalpies of electrolyte solutions
Type de document :	texte imprimé
Auteurs :	Xinlei Ge, Auteur ; Xidong Wang, Auteur
Année de publication :	2009
Article en page(s) :	p. 2229–2235
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Electrolyte solutions Freezing point depression Boiling point elevation Pitzer theories
Résumé :	A novel approach is presented in this work for predicting the values of freezing point depression and boiling point elevation for electrolyte solutions at different concentrations on the basis of the Pitzer theories. This method treats the enthalpy change of the solution between the normal freezing point or boiling point and the real ones to be linear temperature dependence. Compared with the literature values, this method performs very well; also, the temperature-dependent parameters of some salts are incorporated to investigate temperature effects of this method. Furthermore, a method based on the Clausius−Clapeyron equation is derived for estimation of the enthalpy of vaporization of very high concentration solutions at different temperatures, and the predicted results are highly positive.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801348c

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2218–2228

Titre :	Solubility measurements in the mixed solvent electrolyte system Na2CO3-NaHCO3-monoethylene glycol-water
Type de document :	texte imprimé
Auteurs :	Philip L. Fosbøl, Auteur ; Kaj Thomsen, Auteur ; Erling H. Stenby, Auteur
Année de publication :	2009
Article en page(s) :	p. 2218–2228
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Electrolyte system Atmospheric pressure Schreinemakers method
Résumé :	212 new data points for solubility and density have been measured in the mixed solvent electrolytic CO2−NaHCO3−Na2CO3−monoethylene glycol (MEG)−water system. Measurements were conducted at 2−60 °C at atmospheric pressure. An overview of methods available for determining the carbon dioxide and sodium content is given and the reverse Schreinemakers method was chosen. The method gives the amounts of all the species in the liquid. The solutions have a tendency to form metastable mixtures from which sodium carbonate salt hydrates may precipitate. Thirty metastable data points are reported.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8011648

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2212–2217

Titre :	Group contribution method for predicting melting points of imidazolium and benzimidazolium ionic liquids
Type de document :	texte imprimé
Auteurs :	Yan Huo, Auteur ; Shuqian Xia, Auteur ; Yan Zhang, Auteur
Année de publication :	2009
Article en page(s) :	p. 2212–2217
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Imidazolium--Melting points Benzimidazolium ionic liquids--Melting points
Résumé :	A new model is proposed here to estimate melting points of imidazolium and benzimidazolium ionic liquids (ILs) from chemical structures by using a group contribution method, which considers the contributions of normal groups, ionic groups, and characteristic factors of molecules. The melting points of ILs are fitted by the equation presented in this study. Thirty simple groups and three characteristic factors were defined in the model based on the optimization of property values of 155 ionic liquids. The average relative deviation in this work is less than 5.86%, and calculated values of an additional 35 ILs are compared with the values in the literature. The R2 for 190 ILs is about 0.8984. The results show that melting points of ILs determined by the method are accurate and thus the new model can be applied to predict melting points of ILs.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8011215

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2206–2211

Titre :	Effects of gas temperature fluctuations on the evolution of nitrogenous species during coal devolatilization
Type de document :	texte imprimé
Auteurs :	Hongtao Zhang, Auteur ; Zhang, Jian, Auteur
Année de publication :	2009
Article en page(s) :	p. 2206–2211
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Gas temperature fluctuations Nitrogenous species Coal Devolatilization
Résumé :	The effects of gas temperature fluctuations on the instantaneous evolution processes of nitrogenous species were investigated for pulverized coal particles undergoing devolatilization in a hot gas. The instantaneous mass variations of nitrogenous species released from the particles with diameters of 10−50 μm were computed for different conditions. The instantaneous gas temperature was varied with time either in a simple harmonic way or in a random way. The calculated results showed that, under different time-average gas temperatures, the HCN evolution behaviors of particles with different diameters were all affected by the gas temperature fluctuations. The gas temperature fluctuations led to more rapid HCN release from the pulverized coal particles compared to the results obtained without gas temperature fluctuations. The effects were further enhanced by increasing the amplitude or intensity of the gas temperature fluctuations.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801076u

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2199–2205

Titre :	Internal treatment of process waters in paper production by dissolved air flotation with newly developed chemicals. 1. laboratory tests
Type de document :	texte imprimé
Auteurs :	Ruben Miranda, Auteur ; Carlos Negro, Auteur ; Angeles Blanco, Auteur
Année de publication :	2009
Article en page(s) :	p. 2199–2205
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Inorganic polyaluminium salts Organic cationic polyelectrolytes Dissolved air flotation Chemical optimization
Résumé :	New chemicals, based on the synergistic effect between inorganic polyaluminium salts and organic cationic polyelectrolytes, have been tested for the chemical optimization of a dissolved air flotation (DAF) unit, used as internal treatment of process waters in a paper mill based on 100% recovered paper. Laboratory tests have demonstrated that polyamine modifications of the aluminum salts are the most efficient in the removal of contaminants, the combination of a polyaluminium nitrate sulfate salt and a polyamine being the most efficient. This chemical has been studied under different conditions, such as different dosages or in combination with a flocculant for the treatment of waters from different paper grades production, and the results have demonstrated a good performance at laboratory scale. Therefore, a field trial has been recommended for assessing its potential benefits at mill scale, which will be described in a future paper.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801047h

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2188–2198

Titre :	Integrated modeling of mixture fluid phase equilibrium experiments using SAFT-VR applied to xenon + diborane, xenon + cyclopropane, xenon + boron trifluoride
Type de document :	texte imprimé
Auteurs :	M. Pollock, Auteur ; Adjiman, C. S., Auteur ; A. Galindo, Auteur
Année de publication :	2009
Article en page(s) :	p. 2188–2198
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Vapor−liquid equilibrium Integrated self-consistent approach Pure component model SAFT-VR calculations
Résumé :	An intermolecular parameter estimation procedure is incorporated into a model of a static cell vapor−liquid equilibrium experiment where only the total pressure and temperature are measured, so that compositions are not available experimentally. The coexistence compositions are often obtained from the raw experimental measurements by data reduction, in which a (mostly empirical) thermodynamic description must be assumed to represent the liquid and vapor phases. The molecular interaction parameters inherent in a more advanced equation of state treatment are then estimated from this pretreated data for the coexistence compositions. This can lead to a bias in the development of the mixture model and does not allow a statistical analysis to be applied to the model. To overcome these limitations, an integrated self-consistent approach is developed in this work. The pure component model parameters are used with an equation of state to calculate the amount of substance in the experimental apparatus, and the mixture parameters are obtained from parameter estimation based on a model of the experimental setup and the representation of the vapor−liquid equilibrium. This type of integrated approach, best achieved by close integration of detailed experimental information and the theoretical treatment, is tested on three well-studied and characterized binary mixtures: xenon + diborane; xenon + cyclopropane; and xenon + boron trifluoride. The statistical associating fluid theory for potentials of variable range (SAFT-VR) is the equation of state used in this work; the molecular models inherent in the approach are associating chain molecules formed from square-well segments. Excellent agreement between SAFT-VR calculations of the fluid phase equilibrium and experimental data is obtained for all three mixtures, without a priori knowledge of the compositions of the coexisting phases. In the case of xenon + boron trifluoride, the region of liquid−liquid immiscibility and the vapor−liquid−liquid three-phase line are accurately predicted. The effect of experimental error is incorporated into the parameter estimation procedure so that the confidence in the optimal parameters can be evaluated providing guidance in choosing which parameters to estimate with confidence. For comparison, SAFT-VR models are also developed using the reduced data for the coexistence compositions. The description of the fluid phase equilibrium and the values of the intermolecular parameters are found to be similar to those obtained from the integrated approach. The integrated approach presented is general and can be modified to specific static cell apparatus or applied to other types of mixtures or with other equations of state.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800928s

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2179–2187

Titre :	Sewage sludge pyrolysis in a fluidized bed, 2: influence of operating conditions on some physicochemical properties of the liquid product
Type de document :	texte imprimé
Auteurs :	I. Fonts, Auteur ; A. Juan, Auteur ; G. Gea, Auteur
Année de publication :	2009
Article en page(s) :	p. 2179–2187
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Sewage sludge Fluidized bed
Résumé :	Sewage sludge was pyrolyzed at different operating conditions with the aim of producing pyrolysis liquid. In this work, the influence of some operating conditions was studied in relation to some liquid properties such as homogeneity (phase separation), solids content, water content, and high heating value. The operating variables studied were bed temperature (450−650 °C), inlet nitrogen rate (0.057−0.090 m s−1), and solid feed rate per volumetric unit (0.169−0.338 kg s−1 m−3). Phase separation appeared in the samples obtained at almost all operating conditions studied, and it was different depending on the operating temperature and the sample of sewage sludge. The experimental methodology for analyzing the quantitative properties of the pyrolysis liquid under study was based on experimental design techniques. These liquid properties were influenced in different ways by the three studied operating conditions, but above all by the temperature, the inlet nitrogen rate, and also the sample of sewage sludge. Based on the experimental data, empirical models were built to describe the influence of the operating conditions on the liquid properties. Additionally, using these empirical models, operating conditions (within the intervals under study) that allow a high liquid yield and a liquid product with desirable values of the studied properties to be obtained were predicted theoretically.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801448g

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2172–2178

Titre :	DFT calculations on the role of base in the reaction between CO2 and monoethanolamine
Type de document :	texte imprimé
Auteurs :	Jae-Goo Shim, Auteur ; Jun-Han Kim, Auteur ; Young H. Jhon, Auteur
Année de publication :	2009
Article en page(s) :	p. 2172–2178
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	DFT calculations Polarizable continuum model CO2 Monoethanolamine
Résumé :	DFT calculations using a PCM solvation model were carried out to examine the reaction pathways for the formation of carbamate from CO2 and monoethanolamine (MEA) in the presence of an additional proton acceptor, MEA or H2O. In both cases, the zwitterionic species [HO(CH2)2NH2+—COO−] has a lower energy than the reactants. Proton transfer from the zwitterionic species to the base (MEA) produced a carbamate product with an accompanying gradual decrease in energy. However, a similar process for the water case resulted in an implausible increase in energy, which suggests that MEA is suitable as a base but H2O is not.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800684a

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2162–2171

Titre :	Thermal evolution and luminescence properties of Zn-Al-layered double hydroxides containing europium(III) complexes of ethylenediaminetetraacetate and nitrilotriacetate
Type de document :	texte imprimé
Auteurs :	Cang Li, Auteur ; Lianying Wang, Auteur ; David G. Evans, Auteur
Année de publication :	2009
Article en page(s) :	p. 2162–2171
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Ethylenediaminetetraacetate Nitrilotriacetate Layered double hydroxides
Résumé :	Europium complexes of ethylenediaminetetraacetate (EDTA) and nitrilotriacetate (NTA), [Eu(EDTA)(H2O)3]−, and [Eu(NTA)2(H2O)]3−, which have similar geometries but different charge densities, have been incorporated in Zn−Al layered double hydroxides (LDHs). The orientation and loading of the guest anions as well as their thermal stability and reorientation behavior are significantly influenced by their charge density. The maximal dimension of the [Eu(EDTA)(H2O)3]− anion is nearly perpendicular to the LDH layers and a reversible reorientation occurs on mild heating. The structural changes that occurred on heating were followed by variable temperature photoluminescence (PL) measurements. The kinetics of the structural transformation of ZnAl-Eu(EDTA) LDH in the temperature range 30−150 °C have also been studied. In the case of [Eu(NTA)2(H2O)]3−, the anion adopts a flat orientation in the interlayer galleries with its maximum dimension nearly parallel to the metal hydroxyl layers and no reorientation is observed on heating.

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2157–2161

Titre :	Kinematic viscosity and refractive index of aqueous solutions of ethanol and glycerol
Type de document :	texte imprimé
Auteurs :	Ramon Moreira, Auteur ; Francisco Chenlo, Auteur ; Damien LeGall, Auteur
Année de publication :	2009
Article en page(s) :	p. 2157–2161
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Kinematic viscosity Glycerol/ethanol/water Correlations
Résumé :	The kinematic viscosity of ternary solutions of glycerol/ethanol/water was determined at several temperatures (from 20 to 45 °C) and different molar fractions of the components (to 0.75 for ethanol and 0.60 for glycerol) covering a wide range of experimental conditions. A capillary viscometer was used for the measurements. The experimental kinematic viscosity data showed nonideal behavior. Modeling was based on previously proposed correlations for aqueous ethanol solutions modified with an additional exponential term in which the influence of glycerol is taken into account. The final model reproduced the experimental kinematic viscosity data of glycerol/ethanol/water solutions as a function of concentration and temperature with average deviations of 4.6% in the tested range. Refractive indices (at 20 °C) of the ternary solutions were also determined, and a empirical model was proposed to evaluate this physical property with high accuracy.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801410d

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2149–2156

Titre :	Anodic degradation of CI reactive blue 221 using graphite and IrO2/TaO2/RuO2 coated titanium electrodes
Type de document :	texte imprimé
Auteurs :	M. Thalamadai Karuppiah, Auteur ; G. Bhaskar Raju, Auteur
Année de publication :	2009
Article en page(s) :	p. 2149–2156
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	CI reactive blue Biorecalcitrant reactive dye Coated titanium electrodes Chemical oxygen demand Spectrophotometric method Organic carbon measurements
Résumé :	Anodic degradation of the biorecalcitrant reactive dye CI Reactive Blue 221 was investigated using graphite and IrO2/TaO2/RuO2 coated titanium electrodes in a batch reactor setup. The decolorization and mineralization of the dye molecule was monitored by UV−visible spectrophotometric method and chemical oxygen demand (COD) and/or total organic carbon (TOC) measurements, respectively. The effect of different electrolytes and applied current density on the mineralization of CI Reactive Blue 221 in the presence of different electrode materials was studied. Though both the electrode materials were found to be effective for decolorization, complete mineralization of the dye was accomplished in the presence of graphite over a pH range of 6.0−8.0. The efficiency of the electrode material was evaluated in terms of instantaneous current efficiency (ICE), electrochemical oxidizability index (EOI), and specific energy consumption (Esp). The metabolites formed during the degradation reaction were identified using GC-MS, and the degradation pathway was proposed.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801291h

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2142–2148

Titre :	Preparation and SO2 sorption/desorption behavior of an ionic liquid supported on porous silica particles
Type de document :	texte imprimé
Auteurs :	Zhengmin Zhang, Auteur ; Linbo Wu, Auteur ; Jie Dong, Auteur
Année de publication :	2009
Article en page(s) :	p. 2142–2148
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Ionic liquid Porous silica particles Impregnation-vaporization method
Résumé :	The ionic liquid 1,1,3,3-tetramethylguanidinium lactate (TMGL) was supported onto porous silica particles via a facile impregnation−vaporization method. The TMGL-supported particles gave high porosity and large specific surface area. The SO2 sorption/desorption properties of the silica-supported TMGL (TMGL−SiO2) were evaluated, and high SO2 sorption capacity and rate were achieved. Its capacity reached 0.6 g SO2/g TMGL in 15−30 min with pure SO2 gas and 0.15 g SO2/g TMGL in 17 h with a N2/SO2 mixture gas that contained 2160 ppm SO2. The SO2 concentration was reduced to 12.6 ppm after sorption. The TMGL−SiO2 system could be reused for many sorption/desorption cycles without change in its capacity. It was also characterized by good mechanical strength and thermal stability at temperature up to 130 °C. The SO2 sorbent system appears to be useful in gas desulfurization.

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2135–2141

Titre :	Novel regenerable magnesium hydroxide sorbents for CO2 capture at warm gas temperatures
Type de document :	texte imprimé
Auteurs :	Ranjani V. Siriwardane, Auteur ; Robert W. Stevens,Jr., Auteur
Année de publication :	2009
Article en page(s) :	p. 2135–2141
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Magnesium hydroxide sorbents Carbon dioxide Thermodynamic analysis
Résumé :	A novel sorbent consisting of Mg(OH)2 was developed for carbon dioxide (CO2) capture at 200−315 °C suitable for CO2 capture applications such as coal gasification systems. Thermodynamic analysis conducted with the FactSage software package indicated that the Mg(OH)2 sorbent system is highly favorable for CO2 capture up to 400 °C at 30 atm. MgCO3 formed during sorption decomposes to release CO2 at temperatures as low as 375 °C up to 20 atm. MgO rehydroxylation to form Mg(OH)2 is possible at temperatures up to 300 °C at 20 atm. The experimental data show that the sorbent is regenerable at 375 °C at high pressure and that steam does not affect the sorbent performance. A multicycle test conducted in a high-pressure fixed-bed flow reactor at 200 °C with 28% CO2 showed stable reactivity during the cyclic tests. The capture capacity also increased with increasing pressure. The sorbent is unique because it exhibits a high CO2 capture capacity of more than 3 mol/kg at 200 °C and also is regenerable at a low temperature of 375 °C and high pressure. High-pressure regeneration is advantageous because the CO2 compression costs required for sequestration can be reduced.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8011598

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2129–2134

Titre :	Estimation of liquid-liquid equilibrium for a quaternary system using the GMDH algorithm
Type de document :	texte imprimé
Auteurs :	Shahbaz Zahr Reyhani, Auteur ; Hossein Ghanadzadeh, Auteur ; Puigjaner, Luis, Auteur
Année de publication :	2009
Article en page(s) :	p. 2129–2134
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Liquid-liquid equilibrium GMDH technique Corn oil Oleic acid Ethanol Water
Résumé :	Liquid−liquid equilibrium (LLE) data are important for designing and modeling of process equipment. In this article, the group method of data handling (GMDH) technique has been used to estimate LLE data of the quaternary system of corn oil + oleic acid + ethanol + water at 298.15 K. Using this method, a new model has been proposed that is suitable for use in predicting LLE data. The equilibrium data presented herein were predicted using the GMDH model. To evaluate the performance of the GMDH method, we compared the data predicted using the proposed model with experimental data. Moreover, we compared the deviation between the experimental data and the data estimated with the GMDH. We also used the deviations of some existing models for the comparison. The results show that the proposed model can be used as an efficient tool for estimating LLE data.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801082s

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2125–2128

Titre :	Modeling the adsorption kinetics of divalent metal ions onto pyrophyllite using the integral method
Type de document :	texte imprimé
Auteurs :	Neelmani Gupta, Auteur ; Murari Prasad, Auteur ; Nidhi Singhal, Auteur
Année de publication :	2009
Article en page(s) :	p. 2125–2128
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Adsorption system Metal cations Nonlinear sorption kinetic model
Résumé :	The adsorption system was modeled and simulated to predict kinetic parameters for the adsorption of metal cations (lead, copper, and zinc) onto pyrophyllite, a low-cost adsorbent. The developed nonlinear sorption kinetic (NSK) mathematical model was solved using numerical integration (trapezoidal method), the gradient descent method, and least-squares analysis. It was based on application of the Freundlich isotherm to mass transfer across the film surrounding the adsorbent. Batch adsorption experiments were carried out for cation concentrations varying from 5.0 to 100.0 mg L−1. Code was developed in C language both for numerically integrating the model equation and for obtaining the best simulated values of the Freundlich constants, K and N; the order of reaction, n; and the film transfer coefficient, α. The model was sensitive to parameters α, n, and N, whereas it is insensitive to K. The values of parameters N, n, and α lie in the ranges of 0.185−2.06, 0.943−1.341, and 0.009−0.113 [(L/mg)n−1 min−1], respectively, under different experimental conditions.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800975m

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2118–2124

Titre :	Efficiency of amine-modified poly(glycidyl methacrylate)-grafted cellulose in the removal and recovery of vanadium(V) from aqueous solutions
Type de document :	texte imprimé
Auteurs :	T. S. Anirudhan, Auteur ; S. Jalajamony, Auteur ; L. Divya, Auteur
Année de publication :	2009
Article en page(s) :	p. 2118–2124
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Cellulose anion exchanger Glycidyl methacrylate Hydrochloric acid treatment
Résumé :	A cellulose-based anion exchanger (Cell-AE) bearing the —N+HR2Cl− functional group was prepared through graft copolymerization of glycidyl methacrylate onto cellulose (Cell) in the presence of N,N′-methylenebisacrylamide as a cross-linker using benzoyl peroxide as the initiator, followed by amination and hydrochloric acid treatment. The adsorbent was characterized by infrared spectroscopy, scanning electron microscopy, surface area analysis, thermogravimetry, and potentiometric titrations. Batch experiments were performed to evaluate the adsorption efficiency of Cell-AE toward V(V) ions in aqueous solutions. The maximum removal was observed in the pH range of 4.0−6.0. The adsorption process achieved more than 99.6% V(V) removal from an initial concentration of 25.0 mg/L. Adsorption kinetic data were described by pseudo-second-order equation. The equilibrium data fitted very well with the Langmuir model, and the maximum adsorption capacity of Cell-AE toward V(V) was found to be 197.75 mg/g at 30 °C. Over 96.0% desorption of V(V) was achieved with 0.1 M NaOH solution.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8000869

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2113–2117

Titre :	Removal of Cr(VI) ions by spent tea and coffee dusts : reduction to Cr(III) and biosorption
Type de document :	texte imprimé
Auteurs :	Syam K. Prabhakaran, Auteur ; K. Vijayaraghavan, Auteur ; R. Balasubramanian, Auteur
Année de publication :	2009
Article en page(s) :	p. 2113–2117
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Spent tea Coffee dusts Cr(VI)
Résumé :	The potential use of spent tea and coffee dusts was investigated for the removal of Cr(VI) from aqueous solution. The removal mechanism was identified as the reduction reaction of Cr(VI) to Cr(III), followed by Cr(III) sorption to the biomass. The phenolic compounds in tea and coffee dusts serve as electron-donor groups for rapid reduction of Cr(VI). The pH edge experiments revealed that Cr(VI) reduction by both tea and coffee dusts was independent of pH whereas reduced Cr(III) adsorption onto biomass was strongly dependent on pH. Isotherm experiments revealed that tea and coffee dusts possess maximum chromium uptakes of 44.9 and 39.0 mg/g, respectively, at pH 4. Among the two isotherm models (Langmuir and Toth), the Toth model better described the chromium biosorption isotherms with high correlation coefficients and low percent error values. A kinetic model based on the redox reaction between Cr(VI) and biomass successfully described the kinetic data. A comparison of these kinetic data with those from Sargassum and Ulva sp., revealed that Cr(VI) reduction rate of coffee dust was 40 times faster than that of Ulva biomass and 144 times faster than that of Sargassum biomass.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801380h

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2107–2112

Titre :	Bromate ion-exchange properties of crystalline akaganéite
Type de document :	texte imprimé
Auteurs :	Ramesh Chitrakar, Auteur ; Satoko Tezuka, Auteur ; Akinari Sonoda, Auteur
Année de publication :	2009
Article en page(s) :	p. 2107–2112
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Crystalline akaganéite Ion-exchange properties BrO3−
Résumé :	We synthesized crystalline akaganéite (β-FeOOH; Cl− type) by hydrolysis of FeCl3 solution at 100 °C and examined the ion-exchange properties with BrO3−. The uptake rate of BrO3− was so fast that equilibrium was attained in 60 min. The uptake was significantly dependent on pH, showing a maximum uptake at pH ≈ 4. From distribution coefficients (Kd) determined with a mixed solution (BrO3−, Cl−, CO32−, and SO42−; each concentration = 0.1 mmol/dm3), crystalline akaganéite showed the highest selectivity toward BrO3−. The BrO3− uptake was fitted well with the Langmuir model.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8011038

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2100–2106

Titre :	Vacuum evaporation of waste oil-in-water emulsions from a copper metalworking industry
Type de document :	texte imprimé
Auteurs :	Gemma Gutiérrez, Auteur ; José M. Benito, Auteur ; José Coca, Auteur
Année de publication :	2009
Article en page(s) :	p. 2100–2106
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Vacuum evaporation Waste oil-in-water Copper metalworking industry
Résumé :	The performance of vacuum evaporation was evaluated for the treatment of waste oil-in-water (O/W) emulsions, one synthetic (Multiroll) and two semisynthetic (Unopol and Divinol), used in a copper metalworking industry. A destabilization/settling pretreatment step using Nalco 71243 (NAL, a quaternary polyamine) as flocculant and CaCl2 and AlCl3·6H2O as coagulants was also investigated. The quality of the final aqueous effluent was evaluated in terms of chemical oxygen demand (COD), turbidity, conductivity, and biological oxygen demand (BOD5). COD reduction greater than 99% was achieved. The pretreatment step did not significantly improve either the evaporation rate or the quality of the condensate. Moreover, evaporation of a totally exhausted Unopol waste emulsion carried out in an industrial falling film evaporator showed good agreement with results obtained at the laboratory scale.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801054d

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2093–2099

Titre :	Equilibrium isotherm studies for the multicomponent adsorption of lead, zinc, and cadmium onto Indonesian peat
Type de document :	texte imprimé
Auteurs :	R. Balasubramanian, Auteur ; S. V. Perumal, Auteur ; K. Vijayaraghavan, Auteur
Année de publication :	2009
Article en page(s) :	p. 2093–2099
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Indonesian peat Pb Cadmium Zinc Langmuir two-site model
Résumé :	This study evaluates the potential of Indonesian peat to sequester Pb, Cd, and Zn in single-, double-, and triple-solute systems. The adsorption isotherms of Pb, Cd, and Zn onto peat in single-solute and multisolute systems were simulated using the Langmuir two-site model satisfactorily. The model and experimental data of binary and ternary systems demonstrated that the presence of the secondary metal ions in the system resulted in a decrease in the sorption capacity of the primary metal, mainly because of the competitive effects of metals for adsorption sites. The metal adsorption follows the order of sequence Pb > Cd > Zn for both single-solute and multisolute systems. A three-dimensional representation of the total metal uptake in binary systems showed a good agreement with the corresponding experimental data. In addition to ion exchange, a surface adsorption−complexation mechanism must be involved in the sorption mechanism of metal ions. Fourier transform IR results confirm that the carboxyl functional groups participated in metal binding. Desorption experiments revealed that greater than 90% of Pb, Cd, and Zn can be eluted from the peat. In addition, results suggested that the desorption efficiency decreased with an increase in the adsorbed metal concentration.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801022p

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2085–2092

Titre :	Study on electrolytic recoveries of carbonate salt and uranium from a uranyl peroxo carbonato complex solution generated from a carbonate-leaching process
Type de document :	texte imprimé
Auteurs :	Kwang-Wook Kim, Auteur ; Yeon-Hwa Kim, Auteur ; Se-Yoon Lee, Auteur
Année de publication :	2009
Article en page(s) :	p. 2085–2092
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Electrolytic decarbonation Carbonate salt Uranium
Résumé :	This work studied an electrolytic decarbonation by using an electrolytic system consisting of a cation exchange membrane-equipped cell and a gas absorber for simultaneous recoveries of carbonate salt and uranium from a uranium-bearing carbonate solution generated from a uranium leaching process using carbonate and hydrogen peroxide. The system was effective for the recoveries of carbonate salt and uranium as a precipitate of uranium peroxide hydrate from the solution and for a treatment of the residual hydrogen peroxide in the solution. The existence of uranium and hydrogen peroxide in a carbonate solution did not affect the electrolytic recovery characteristics of the carbonate salt from the solution. The behavior of the voltage or current during the electrolysis in the system could be explained by the characteristics of change of the species generated depending on the pH in the anodic and cathodic chambers. In the system, the constant current operation was better than the constant voltage operation from the energy consumption point of view. The electrolytic method used in this work for the recovery of carbonate salt from a carbonate-leaching solution containing uranium was evaluated to be environmentally friendly because it could minimize the generation of secondary wastes.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800990r

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2076–2084

Titre :	Adsorption of arsenic on conditioned layered double hydroxides : column experiments and modeling
Type de document :	texte imprimé
Auteurs :	Megha Dadwhal, Auteur ; Mayur M. Ostwal, Auteur ; Paul K. T. Liu, Auteur
Année de publication :	2009
Article en page(s) :	p. 2076–2084
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Arsenic Layered double hydroxide adsorbents Packed-bed columns
Résumé :	The removal of As(V) by conditioned, calcined layered double hydroxide (LDH) adsorbents is investigated in continuous-flow, packed-bed columns, in order to study the effect of important operating parameters, such as the influent As concentration, the pH, the adsorbent particle size, and the flow rate. Earlier bed saturation and breakthrough were observed at higher flow rates and influent concentrations. On the other hand, a decrease in the adsorbent particle size and the influent pH resulted in an increase in the number of bed volumes at breakthrough. A column model which accounts for external, liquid-film mass transport and for diffusion and adsorption in the adsorbent particles is utilized. Two different adsorption models are employed, which were shown previously to be capable of predicting the As(V) uptake by LDH adsorbents. They are a conventional homogeneous surface diffusion model and a bidisperse pore model, the latter viewing the LDH particles as assemblages of microparticles and taking into account bulk diffusion in the intraparticle pore space, and surface diffusion within the microparticles themselves. Both models are found capable of predicting the flow-column experimental results.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800878n

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2066–2075

Titre :	Activated carbons for the removal of low-concentration gaseous toluene at the semipilot scale
Type de document :	texte imprimé
Auteurs :	Juan Carratalà-Abril, Auteur ; Maria Angeles Lillo-Ródenas, Auteur ; Angel Linares-Solano, Auteur
Année de publication :	2009
Article en page(s) :	p. 2066–2075
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Low-concentration gaseous toluene Activated carbons Semipilot plant scale
Résumé :	The present paper focuses on the removal of low-concentration gaseous toluene by adsorption on activated carbons (AC) at the semipilot plant scale. The performance of AC prepared by chemical and physical activation is analyzed and compared with a commercial AC. Our results have shown similar shapes for the breakthrough curves in the physically AC and the commercial AC, close to ideality, and similar lengths of the mass transfer zone, despite their different pore size distributions. This behavior is mostly related to a strong adsorbate−adsorbent interaction for the three AC, whereas this interaction has proved to be weaker in the chemically activated ones. The narrow micropore volume influences the breakthrough and saturation times, and a simple kinetic model has been used to fit the experimental data leading to good prediction of the adsorption capacities. A mathematical model, suitable for diluted concentrations, has been used to simulate the breakthrough curves. This model has proved to be useful to fit curves at laboratory scale and predict the adsorption behavior at larger scales.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800521s

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2061–2065

Titre :	Preparation and characterization of ultrathin palladium membranes
Type de document :	texte imprimé
Auteurs :	X. Li, Auteur ; T. M. Liu, Auteur ; D. Huang, Auteur
Année de publication :	2009
Article en page(s) :	p. 2061–2065
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Ultrathin palladium membrane Photocatalytic deposition pretreatment Electroless modification method
Résumé :	An ultrathin palladium membrane (1 μm) has been prepared by an improved photocatalytic deposition (PCD) pretreatment and the electroless modification method. SEM results demonstrated good adhesion of the plated palladium membrane on the porous composite TiO2 support and dense coalescence of the palladium membrane. The flux and H2/N2 selectivity of the palladium membrane were determined in the temperature range of 623−823 K and the pressure difference range of 0.02−0.15 MPa. At 673 K and 0.1 MPa pressure difference, the hydrogen permeation flux of the composite membrane was as high as 0.27 mol m−2 s−1, and the H2/N2 selectivity coefficient was 361. In this study, the activation energy of hydrogen permeation through the composite palladium membrane was 17 kJ/mol. The corrected pressure exponent for the palladium composite membrane was nearly 0.8 deviated from Sievert’s law.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8004644

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2056–2060

Titre :	Study on Mg2+ removal from ammonium dihydrogen phosphate solution by predispersed solvent extraction
Type de document :	texte imprimé
Auteurs :	JianHong Luo, Auteur ; Jun Li, Auteur ; Jin Yang, Auteur
Année de publication :	2009
Article en page(s) :	p. 2056–2060
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Mg2+ Predispersed solvent extraction Aqueous solution Colloidal liquid aphrons
Résumé :	The predispersed solvent extraction (PDSE) is a new method for separating solutes from aqueous solution, and for its high extraction ratio, the PDSE presents huge potential for the extraction from dilute solution. In the present paper, colloidal liquid aphrons are successfully generated using kerosene as a solvent, di(2-ethylhexyl)phosphoric acid (D2EHPA) as an extractant, sodium dodecyl benzene sulfate (SDBS) as surfactant in the aqueous phase, and polyoxyethylene sorbitol anhydride monolaurate (Tween-20) in oil phase. The extraction of Mg2+ from ammonium dihydrogen phosphate solution is studied by using colloidal liquid aphrons (CLA) and colloidal gas aphrons (CGA) in a semibatch extraction column. To study the extraction ratio and advantages of the PDSE process in the removal of Mg2+, various parameters, initial Mg2+ concentration, D2EHPA volume fraction, reaction temperature, phase volume ratio, mass fractions of dodecyl trimethylammonium bromide (HTAB), mass fractions of SDBS, mass fractions of Tween-20, and initial pH of NH4H2PO4 solution, are studied and optimized. The results show that Mg2+ in NH4H2PO4 solution can be effectively removed by the PDSE process. An extraction ratio of more than 86.3% is attained at the optimized parameters, and superior-grade NH4H2PO4 (MAP) can be obtained by two levels of extraction.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801277t

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2049–2055

Titre :	Simulation of hydrodesulfurization reactive column using the research institute of petroleum industry method
Type de document :	texte imprimé
Auteurs :	Hamid Reza Mahdipoor, Auteur ; Keyvan Khorsand, Auteur ; Mehdi Mohammadi, Auteur
Année de publication :	2009
Article en page(s) :	p. 2049–2055
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Hydrodesulfurization process Reactive column Computer simulation RIPI method
Résumé :	In the new hydrodesulfurization (HDS) process by integrating the reaction and separation units in a single reactive column, the fixed cost and operational costs can be reduced, as well as more flexible operating conditions will be achievable. For investigating both the design and the operating aspects of reactive columns, computer simulation is needed. This study was performed using the RIPI (Research Institute of Petroleum Industry) method in different conditions such as various operating temperatures and pressures. For verifying the presented solving method, the results of simulating a typical n-butane absorber column by RIPI method were compared to the achieved results from the well-known inside-out method. The results show the capability of the RIPI method in converging the computations. Moreover, by substituting the power law model by the Langmuir−Hinshelwood kinetic model in computations, the effect of pressure variations on the HDS reactive column was investigated.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801503m

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2034–2048

Titre :	Deepening internal mass integration in design of reactive distillation columns, 1: principle and procedure
Type de document :	texte imprimé
Auteurs :	Jie Sun, Auteur ; Kejin Huang, Auteur ; Shaofeng Wang, Auteur
Année de publication :	2009
Article en page(s) :	p. 2034–2048
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Reactive distillation column Internal mass integration Catalyst
Résumé :	For a reactive distillation column involving reactions with negligible or no thermal effect, the thermodynamic efficiency can be improved substantially through deepening internal mass integration between the reaction operation and the separation operation involved. Four strategies, including the superimposition of reactive section onto rectifying and stripping sections, relocation of feed stages, and redistribution of catalyst within the reactive section, can be used to intensify the internal mass integration. With a systematic application of these strategies, a sequential procedure is devised for the synthesis and design of reactive distillation columns involving reactions with negligible or no thermal effect. Four hypothetical ideal reactive distillation systems are used as examples to evaluate the philosophy proposed, and a substantial reduction of utility consumption is secured in addition to a further abatement in fixed investment. These striking results are evidence of the strong necessity and efficacy of deepening internal mass integration in the synthesis and design of reactive distillation columns involving reactions with negligible or no thermal effect.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801144n

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2020–2033

Titre :	Validations of thermohydraulic models for geysering in a natural circulation loop using an impedance needle probe
Type de document :	texte imprimé
Auteurs :	S. Paruya, Auteur ; Saha, A. K., Auteur ; P. Bhattacharya, Auteur
Année de publication :	2009
Article en page(s) :	p. 2020–2033
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Thermohydraulic models Geysering instability Short-tube natural circulation evaporator Impedance void-needle probe
Résumé :	This paper describes the validations of thermohydraulic models that predict the geysering instability observed at the riser section of a short-tube natural circulation evaporator (STNCE) at low heat flux and low pressure. The validations have been made by measuring the void fraction in the steam−water system at the riser section of a STNCE with the help of an impedance void-needle probe. The calibration of the probe shows that in the range of low void fractions the probe indicates lower values while in the range of high void fractions it indicates higher values compared to those measured by the manometer. Measured data of void fraction have been analyzed by thermohydraulic models. Both measured data and simulated data of temporal variation of void fractions during geysering have been observed to be periodic pulses of high amplitudes. Effects of riser height and loop resistance on the geysering frequency have been demonstrated in detail. The paper also discusses both the measurement uncertainties and the model uncertainties.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8005462

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2009–2019

Titre :	An extended formulation for the flexible short-term scheduling of multiproduct semicontinuous plants
Type de document :	texte imprimé
Auteurs :	Elisabet Capon-Garcia, Auteur ; Sergio Ferrer-Nadal, Auteur ; Moisès Graells, Auteur
Année de publication :	2009
Article en page(s) :	p. 2009–2019
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Semicontinuous plants Flexible environments
Résumé :	Chemical plants are moving toward more-flexible environments, to adapt faster to market changes. For the sake of this flexibility, batch and continuous units might be integrated and operated along the same processing route in a semicontinuous mode, featured by production campaigns of finite duration. Constant production rates for the entire operation have been usually considered. Thus, production adjustments were achieved through storage resources, production line stops, and multiple product campaigns. The objective of this work is to improve the production schedules by developing a new concept for flexible manufacturing, which allows one to program production rate profiles within each semicontinuous operation campaign. Hence, the extended formulation presented allows to address the tradeoff between the opportunities that may arise when adjusting processing rates and the storage needs and opportunities. Finally, several case studies show that the proposed adjustment of the processing rates leads to less storage utilization and more-efficient production performance.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800539f

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2003–2008

Titre :	Design of optimal and near-optimal enterprise-wide supply networks for multiple products in the process industry
Type de document :	texte imprimé
Auteurs :	L. T. Fan, Auteur ; Young Kim, Auteur ; Choamun Yun, Auteur
Année de publication :	2009
Article en page(s) :	p. 2003–2008
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Optimal enterprise-wide networks Feedstocks Graph-theoretic method Mixed integer linear programming problem
Résumé :	The optimal and near-optimal enterprise-wide networks are designed, that is synthesized, for supplying feedstocks and distributing multiple products manufactured from these feedstocks in the process industry by resorting to the graph-theoretic method based on process graphs (P-graphs). Such feedstocks and products, conveyed through supply networks, are invariably materials for which the law of mass conservation is universally valid. Moreover, any of the actions applied to or exerted on a given feedstock or product, transiting through the supply networks, will induce a change in at least one of its attributes, thereby transforming the feedstock or product. Examples of the actions are loading, blending, pumping, tracking, unloading, subdividing, and/or wrapping; and those of the attributes are chemical composition, physical state, flow characteristics, external appearance, and/or location. Thus, in the broadest sense, any supply network can be regarded as a process network. The feedstocks and the products manufactured from them serve as the raw materials for and the products from the supply network at its entrance and exit, respectively. An operating, that is functional, unit can be unequivocally identified where any action is exerted on these raw materials or products. Naturally, the networks can be represented graph-theoretically as P-graphs. The proposed method is illustrated with an example involving three process plants, three markets, and three products under the three scenarios of coordination, cooperation, and competition. It has given rise simultaneously to the optimal as well as near-optimal supply networks in the ranked order. The example, formulated as the mixed integer linear programming problem, yields the same optimal solutions only, but not the near-optimal solutions in the ranked order.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800447g

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1989–2002

Titre :	Optimal design of clinical tests for the identification of physiological models of type 1 diabetes mellitus
Type de document :	texte imprimé
Auteurs :	Federico Galvanin, Auteur ; Massimiliano Barolo, Auteur ; Sandro Macchietto, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1989–2002
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Type 1 diabetes mellitus Artificial pancreas Dynamic simulation model Glucose-insulin system
Résumé :	Type 1 diabetes mellitus is a disease affecting millions of people worldwide and causing the expenditure of millions of euros every year for health care. One of the most promising therapies derives from the use of an artificial pancreas, based on a control system able to maintain the normoglycaemia in the subject affected by diabetes. A dynamic simulation model of the glucose−insulin system can be useful in several circumstances for diabetes care, including testing of glucose sensors, insulin infusion algorithms, and decision support systems for diabetes. This paper considers the problem of the identification of single individual parameters in detailed dynamic models of glucose homeostasis. Optimal model-based design of experiment techniques are used to design a set of clinical tests that allow the model parameters to be estimated in a statistically sound way, while meeting constraints related to safety of the subject and ease of implementation. The model with the estimated set of parameters represents a specific subject and can thus be used for customized diabetes care solutions. Simulated results demonstrate how such an approach can improve the effectiveness of clinical tests and serve as a tool to devise safer and more efficient clinical protocols, thus providing a contribution to the development of an artificial pancreas.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801209g

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1980–1988

Titre :	A two-stage method for identification of dual-rate systems with fast input and very slow output
Type de document :	texte imprimé
Auteurs :	Shengyong Mo, Auteur ; Xi Chen, Auteur ; Jun Zhao, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1980–1988
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Dual-rate system Finite impulse response Combined least-squares criterion Newton-Raphson method
Résumé :	A dual-rate system with fast input and very slow output is very common in the chemical process industry. To identify its original fast single-rate model based on the output error method, a two-stage method combining techniques for dealing with initialization and local minimum problems is proposed in this paper. In its first stage, a finite impulse response (FIR) model is developed directly from the original dual-rate sampled data using the combined least-squares criterion and Newton−Raphson (N−R) method. In the second stage, a single-and-fast-rate output error model is developed on the basis of the original fast input signal and the derived slow rate model output. Besides the simulation examples, the method is also applied to develop a composition observer for an industrial distillation column.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800948g

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1973–1979

Titre :	Convex hull discretization approach to the global optimization of pooling problems
Type de document :	texte imprimé
Auteurs :	Viet Pham, Auteur ; Carl Laird, Auteur ; Mahmoud El-Halwagi, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1973–1979
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Pooling problem Convex-hull Mixed integer linear program
Résumé :	The pooling problem is an important optimization problem that is encountered in process operation and scheduling. Because of the presence of bilinear terms, the traditional formulation is nonconvex. Consequently, there is a need to develop computationally efficient and easy-to-implement global-optimization techniques. In this paper, a new approach is proposed based on three concepts: linearization by discretizing nonlinear variables, preprocessing using implicit enumeration of the discretization to form a convex-hull which limits the size of the search space, and application of integer cuts to ensure compatibility between the original problem and the discretized formulation. The continuous quality variables contributing to the bilinear terms are first discretized. The discretized problem is a mixed integer linear program (MILP) which is globally solvable in a computationally effective manner using the branch and bound method. The merits of the proposed approach are illustrated with case studies from literature and comparison with published results.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8003573

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1957–1972

Titre :	Optimization of a simple ammonia-water absorption refrigeration cycle by application of mixed-integer nonlinear programming
Type de document :	texte imprimé
Auteurs :	Luz María Chávez-Islas, Auteur ; Christopher L. Heard, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1957–1972
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Ammonia-water absorption refrigeration system Mixed-integer nonlinear programming Heat rejection
Résumé :	Optimization of an ammonia−water absorption refrigeration system, minimizing operating and annualized capital costs, is described. A mixed-integer nonlinear programming (MINLP) model, with the inclusion of discontinuous functions for capital costs for the main components of the system, is presented. The minimum total annualized cost is achieved with the simultaneous optimization of seven design variables. Practical limits of the design variables are established for the purpose of generating design parameters in accordance with the type of system studied. The model is applied to two examples. The analysis considers two types of heat rejection media: cooling water and air. The results obtained indicate that the selection of cooling medium is dependent on the refrigeration level that is required. The optimum configuration and operating conditions do not correspond to the best process integration and the coefficients of performance, and irreversibilities are high. The design variables with the highest impact on the objective function are dependent on the heat rejection medium characteristics and the process requirements. A sensitivity analysis of the effects of the evaluation criteria on the minimization of operating and capital costs is presented.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800828w

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1944–1956

Titre :	Design and analysis of an ammonia/water absorption refrigeration cycle by means of an equation-oriented method
Type de document :	texte imprimé
Auteurs :	Luz María Chávez-Islas, Auteur ; Christopher L. Heard, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1944–1956
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Equation-oriented model Ammonia/water absorption refrigeration cycle Thermodynamic model Thermophysical property model
Résumé :	An equation-oriented model for the design of a simple ammonia/water absorption refrigeration cycle is presented, which due to the nature of the working mixture, includes high-quality thermodynamic and thermophysical property models. There are four versions of the model, depending on heat rejection media and distillation column feed conditions. Solution of the model requires the given variables and designer competence-based variables. The column equilibrium stages, diameter, and height use binary decision variables. The solution of the equation set was developed with a General Algebraic Modeling System (GAMS) general purpose nonlinear solver. An equation solution strategy is described. Once solved, exergy balances are made and irreversibilities and exergy efficiency are calculated globally and for each unit operation. Two examples are compared. The great number of factors that can be varied in the absorption refrigeration system makes manual optimization of an industrial design a formidable task. However, good design makes a decisive difference in regard to the use of waste heat absorption refrigeration. The model forms the basis for the simultaneous optimization of design variables with an appropriate objective function.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800827z

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1933–1943

Titre :	Integrated design and control using a simultaneous mixed-integer dynamic optimization approach
Type de document :	texte imprimé
Auteurs :	Rodrigo López-Negrete de la Fuente, Auteur ; Antonio Flores-Tlacuahuac, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1933–1943
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Binary distillation column Mixed-integer nonlinear programming Dynamic optimization approach
Résumé :	In this work, we address the simultaneous design and control of a binary distillation column. The problem is first formulated as a mixed-integer dynamic optimization problem that is then transformed into a mixed-integer nonlinear programming problem using the simultaneous dynamic optimization approach (i.e., full discretization). This formulation is capable of designing the optimal feed tray location, tray sizing, optimal operating steady states, the optimal open-loop trajectory between them, and also the best controller paring and parameters that does the best tracking of the open-loop trajectory. For solving the complex mixed-integer dynamic optimization problem, an optimization decomposition strategy is proposed. The solution strategy is based on solving relaxed versions of the optimization problem and using the results to initialize complex problem versions. The full space problem was solved with the Bonmin solver. Two cases were analyzed, and in both the solver and the proposed decomposition strategy were capable of solving the problems successfully.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801353c

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1928–1932

Titre :	Block copolymer micelles formed in supercritical fluid can become water-dispensable nanoparticles : poly(ethylene glycol)-block-poly(ϵ-caprolactone) in trifluoromethane
Type de document :	texte imprimé
Auteurs :	Zachary Tyrrell, Auteur ; Winoto Winoto, Auteur ; Youqing Shen, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1928–1932
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Micelles Poly(ethylene glycol)−block Poly(ϵ-caprolactone)Supercritical fluid solvent Water-dispensable formulation
Résumé :	Micelles of hydrophilic−hydrophobic block polymers, such as poly(ethylene glycol)−block-poly(ϵ-caprolactone) (PEG−b-PCL), used as drug-delivery carriers, are generally fabricated via solvent displacement or dialysis, which is time-consuming, requires freeze drying, and can leave toxic traces of the residual organic solvents. An alternative is presented in this paper: form micellar PEG−b-PCL nanoparticles in a supercritical fluid solvent and then disperse them in water toward a water-dispensable formulation. This method is illustrated with pressure−temperature phase diagrams for PEG−b-PCL in supercritical trifluoromethane, which is selective enough for the PCL and PEG blocks to induce micellization. When subjected to decompression to remove trifluoromethane, dry and organic solvent-free nanoparticles are readily obtained. Their micellar structure is immediately reestablished in water, as confirmed by laser light scattering. Neither has been demonstrated previously.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801472n

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1921–1927

Titre :	Strategies to estimate the pressure drop threshold of nucleation for polystyrene foam with carbon dioxide
Type de document :	texte imprimé
Auteurs :	Siu N. Leung, Auteur ; Anson Wong, Auteur ; Chul B. Park, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1921–1927
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Pressure drop threshold Polymer foaming processes Bubble nucleation
Résumé :	Two methods to predict the pressure drop threshold (ΔPthreshold) to initiate bubble nucleation in polymer foaming processes are developed. One method uses the modified nucleation theory developed in our previous work, while the other utilizes computer simulations to model the growth profiles of the first observable bubbles in batch foaming experiments. These two approaches have shown reasonably good agreement qualitatively with each other in their ΔPthreshold predictions. Moreover, the effects of the pressure drop rate, the gas content, and the processing temperature on ΔPthreshold are demonstrated. It was found that the pressure drop rate does not have a significant effect on ΔPthreshold, while increasing the gas content or the processing temperature leads to a decrease in ΔPthreshold.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800079x

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1914–1920

Titre :	Fluidized-bed coating with sodium sulfate and PVA-TiO2, 3. The role of tackiness and the tack stokes number
Type de document :	texte imprimé
Auteurs :	Peter Dybdahl Hede, Auteur ; Poul Bach, Auteur ; Anker D. Jensen, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1914–1920
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Fluid-bed coating processes PVA−TiO2 coating Liquid surface phenomena Stokes number
Résumé :	In the first and second parts of this study [Hede, P. D.; Bach, P.; Jensen, A. D. Ind. Eng. Chem. Res. 2009, 48, 1893 and 1905], agglomeration tendencies were studied for two types of coatings: sodium sulfate and PVA−TiO2. Results showed that the agglomeration tendency is always lower for the salt coating process than for the polymer coating process, under similar process conditions, because of differences in stickiness, not because of differences in bulk viscosities. It was further shown that it is possible to optimize the PVA−TiO2 coating formulation and process to achieve a low tendency of agglomeration, similar to the salt coating process. With the PVA−TiO2 coating liquid layer thicknesses encountered during these fluid-bed coating processes, agglomeration seems to be governed primarily by liquid surface phenomena. A modification to the original viscous Stokes number is suggested in the present paper, which defines the Stokes number in terms of the work needed to reach maximum tack instead of the viscous dissipation energy. The new tack Stokes number correlates well with the observed levels of agglomeration and, as a promising feature, proportionality is observed between the agglomeration weight percentage and the difference between the new tack Stokes number and the critical tack Stokes number.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800942c

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1905–1913

Titre :	Fluidized-bed coating with sodium sulfate and PVA-TiO2, 2. Influence of coating solution viscosity, stickiness, pH, and droplet diameter on agglomeration
Type de document :	texte imprimé
Auteurs :	Peter Dybdahl Hede, Auteur ; Poul Bach, Auteur ; Anker D. Jensen, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1905–1913
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Coating stickiness Bulk viscosities PVA-TiO2 coating Salt coating process
Résumé :	In the first part of this study [Hede, P. D.; Bach, P.; Jensen, A. D. Ind. Eng. Chem. Res. 2009, 49, 1914], agglomeration regime maps were developed for two types of coatings: sodium sulfate and PVA−TiO2. It was observed here how the agglomeration tendency is always lower for the salt coating process than for the polymer coating process, under similar process conditions. This is investigated further in this second part and concluded to be due to differences in coating solution stickiness, rather than differences in bulk viscosities. Furthermore, results show that it is possible to optimize the PVA−TiO2 coating formulation and process to achieve a low tendency of agglomeration, similar to that of the salt coating process. The best results for the PVA−TiO2 solution are obtained by substituting the PVA−TiO2 in equal amounts with Neodol 23-6.5 and further reducing the pH value in the coating solution to pH 4.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800941x

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1893–1904

Titre :	Fluidized-bed coating with sodium sulfate and PVA-TiO2, 1. Review and agglomeration regime maps
Type de document :	texte imprimé
Auteurs :	Peter Dybdahl Hede, Auteur ; Poul Bach, Auteur ; Anker D. Jensen, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1893–1904
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Placebo enzyme granules Fluid-bed coating Sodium sulfate Polyvinyl alcohol-titanium dioxide Inorganic salt Ppolymer film coating
Résumé :	This paper, and two associated papers [Hede, P. D.; Jensen, A. D.; Bach, P. Ind. Eng. Chem. Res. 2009, 48, 1905 and 1914], address the fluid-bed coating of placebo enzyme granules (i.e., sodium sulfate cores, with a size range of 400−500 μm) using two types of coatings: sodium sulfate and PVA−TiO2. The coating experiments were conducted in a medium-scale top-spray MP-1 fluid bed, and many rheological experiments were performed on the coating formulations to support the interpretation of the fluid-bed coating results. In this first part of the study, a thorough introduction to the inorganic salt and polymer film coating is provided, along with a presentation of the equipment and materials being used in this and the following papers. Results from agglomeration studies over a broad range of process conditions are presented, showing that the tendency toward agglomeration is always less for the salt coating process than for the polymer coating process, under similar process conditions. Based on the experimental results, an agglomeration regime map is suggested for each of the two types of coating solutions, based on values of the drying force and the coating solution spray rate.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800940e

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1887–1892

Titre :	Carboxymethyl cellulose treatment as a method to inhibit vessel picking tendency in printing of eucalyptus pulp sheets
Type de document :	texte imprimé
Auteurs :	Minna Rakkolainen, Auteur ; Eero Kontturi, Auteur ; Akira Isogai, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1887–1892
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Vessel picking tendency Eucalyptus pulp sheetsCarboxymethyl cellulose
Résumé :	This article presents an industrially feasible method to effectively reduce vessel picking tendency by a simple chemical modification of pulp. ECF-bleached eucalyptus kraft pulp was treated with carboxymethyl cellulose (CMC) under specified conditions. The aim was to study the effects on vessel element structure and vessel picking tendency of the laboratory sheets prepared. In addition to the improved strength properties of the sheets, a significant decrease in vessel picking tendency was noted in the laboratory printing test. Whereas refining improved mainly the bonding ability of fibers, CMC treatment effectively enhanced the bonding of vessels as well. Moreover, filmlike structures were formed in the fibrillated areas of the CMC-treated handsheets, and they were concluded to reinforce bonding within the sheet. Also, fragmentation of vessel elements through CMC modification was found to be important and to result in a decreasing picking tendency.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801476v

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1880–1886

Titre :	High-temperature stability of palladium membranes on porous metal supports with different intermediate layers
Type de document :	texte imprimé
Auteurs :	Ke Zhang, Auteur ; Huiyuan Gao, Auteur ; Zebao Rui, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1880–1886
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Palladium membranes Porous stainless steel Yttria stabilized zirconia
Résumé :	The effectiveness of intermediate layer to prevent intermetallic diffusion is a key factor for application of Pd membranes on porous stainless steel (PSS) support. In this work, electroless-plated Pd membranes were prepared on PSS disks with two different intermediate layers: in situ oxidized metal oxide and sol−gel derived mesoporous yttria stabilized zirconia (YSZ). A thinner, gastight Pd layer can be formed on PSS support with the YSZ intermediate layer, resulting in a higher hydrogen permeance than Pd membranes on PSS support with the in situ oxidized metal oxide intermediate layer. High temperature permeation and 100-h stability tests showed that both intermediate layers were effective as the diffusion barrier for Pd membranes on PSS supports in the temperature range of 773−873 K. At temperatures above 873 K, only the YSZ intermediate layer is effective in preventing intermetallic diffusion and gives a stable Pd membrane. At the elevated temperatures Pd membranes on PSS support with in situ oxidation layer suffer from a chemical and mechanical stability problem due to reduction of metal oxides in hydrogen atmosphere which results in intermetallic diffusion and possibly weakens the adhesion of the Pd layer on PSS support.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801417w

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1873–1879

Titre :	Effect of alkaline treatment on the catalytic performance of ZSM-5 catalyst in pyridine and picolines synthesis
Type de document :	texte imprimé
Auteurs :	Jin Fang, Auteur ; Ye Tian, Auteur ; Yongdan Li, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1873–1879
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Alkaline treatment ZSM-5 catalyst Pyridine Picolines Extra-framework aluminum
Résumé :	An alkaline treatment is employed for tailoring a commercial H-ZSM-5 to produce a catalyst for the synthesis of pyridine and picolines. The most significant consequence of the alkaline treatment was desilication. However, it is accompanied by extraction of aluminum and formation of extra-framework aluminum (Alef) and amorphous alumina. Slit-shaped intracrystaline mesopores and macropores form. Because of the decrease in the Si/Al ratio in the zeolite framework and the formation of Alef and amorphous alumina, the number of strong acid sites decreases and that of weak acid sites increases. The ratio of Lewis acids to Brönsted acids (L/B) also increases. We note that the induced hierarchical pores and the change of acid strength distribution increase the stability of the catalyst, and the increased L/B causes an increase in the initial yield and comparative selectivity for pyridine and a decrease in those properties for 3-picoline. Coking leads to a gradual deactivation and affects product selectivity.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8014457

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1866–1872

Titre :	Modeling and simulation of an industrial trickle-bed reactor for benzene hydrogenation : model validation against plant data
Type de document :	texte imprimé
Auteurs :	Jonas Roininen, Auteur ; Ville Alopaeus, Auteur ; Sami Toppinen, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1866–1872
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Trickle-bed reactor Gas-liquid mass transfer Hydrogen Heterogeneous three-phase reactor model
Résumé :	A heterogeneous three-phase reactor model is used to simulate an industrial trickle-bed reactor for benzene hydrogenation, and simulated temperature profiles are compared to actual plant data. The agreement of model predictions with measured data is excellent. Analysis of the results shows that the process is limited by gas−liquid mass transfer of hydrogen. The simulation results show high sensitivity toward the liquid film mass transfer coefficient kLa. Some correlations for kLa are tested, and their validity is evaluated. The estimated values of kLa and kGa are comparable to measured values from a bench-scale reactor reported in the literature.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801411n

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1859–1865

Titre :	Influences of water and syngas partial pressure on the kinetics of a commercial alumina-supported cobalt Fischer-Tropsch catalyst
Type de document :	texte imprimé
Auteurs :	F. Gideon Botes, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1859–1865
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Alumina-supported cobalt Fischer-Tropsch catalyst Water partial pressure Syngas pressure
Résumé :	The influences of the water partial pressure and the syngas pressure on the reaction kinetics of a commercial alumina-supported cobalt Fischer−Tropsch (FT) catalyst were investigated. Both a fresh catalyst, as well as an aged catalyst from a demonstration reactor, were employed in the study. It was concluded that water has a negligible influence on the overall FT reaction rate but lowers the methane selectivity and increases the CO2 selectivity. Longer term exposure to higher water partial pressures did not lead to step changes in the catalyst activity but may have increased the rate of gradual irreversible catalyst deactivation. Increasing the syngas pressure at constant H2/CO ratio significantly increased the FT reaction rate and decreased the methane selectivity, suggesting a substantial incentive to explore higher pressure operation of commercial cobalt−FT processes.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8013023

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1847–1858

Titre :	Photocatalytic degradation of dichloroacetic acid : a kinetic study with a mechanistically based reaction model
Type de document :	texte imprimé
Auteurs :	María de los Milagros Ballari, Auteur ; Orlando M. Alfano, Auteur ; Alberto E. Cassano, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1847–1858
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Dichloroacetic acid Photocatalytic degradation UV radiation Titanium dioxide suspensions Kinetic model
Résumé :	In the present work, a study of the reaction kinetics of the photocatalytic degradation of dichloroacetic acid (DCA) employing UV radiation and titanium dioxide suspensions is reported. This study involved the development of a kinetic model from a proposed complete reaction sequence and estimation of the kinetic parameters from experimental data. The experimental data were obtained using a perfect mixed photoreactor, because the operating conditions were chosen in compliance with restrictive conditions established in a previous work in which the possibility of mass-transfer limitations in slurry reactors was investigated. The significant variables in this study were (1) the initial DCA concentration, (2) the catalyst loading, and (3) the light intensity. Simulation results from the complete reactor mass balance, including radiation transport in the bulk and resistances inside the catalytic particle agglomeration, are in good agreement with experiments, which provides confidence in the estimation of the kinetic parameters within the range of the explored variables.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801194f

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1840–1846

Titre :	Catalytic hydrogenolysis of glycerol to propylene glycol over mixed oxides derived from a hydrotalcite-type precursor
Type de document :	texte imprimé
Auteurs :	Lekha Charan Meher, Auteur ; Rajesh Gopinath, Auteur ; S. N. Naik, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1840–1846
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Propylene glycol Glycerol Hydrogenolysis Cu/Zn/Al mixed-metal oxide catalysts
Résumé :	Selective hydrogenolysis of glycerol to propylene glycol was performed using an environmentally friendly hydrotalcite-derived mixed-metal oxide catalyst. The Mg/Al, Zn/Al, Ni/Mg/Al, Ni/Co/Mg/Al, and Cu/Zn/Al mixed-metal oxide catalysts were prepared from their corresponding hydrotalcite precursors having M2+/M3+ compositions over the range of 0.5−3.0. The physicochemical properties of the catalysts were studied by X-ray diffraction (XRD), inductively coupled plasma mass spectrometry (ICP-MS), NH3 and CO2 temperature-programmed desorption (TPD), and nitrogen adsorption studies. The XRD patterns of pure hydrotalcites exhibited characteristics of hydrotalcite phases, while those of calcined hydrotalcites showed the formation of corresponding metal oxides. The ICP-MS analysis showed agreement between the calculated and actual metal compositions. The prepared catalysts were evaluated for the hydrogenolysis of glycerol to propylene glycol in a Parr reactor. The activity studies indicated a maximum glycerol conversion and selectivity toward propylene glycol in the case of Cu/Zn/Al mixed-metal oxide catalysts. Further, the reaction parameters were optimized with the most active Cu/Zn/Al catalyst, and it was found that at a catalyst concentration of 5% (w/w) of aqueous glycerol, a hydrogen pressure of 200 psig, and 80% glycerol dilution, a maximum glycerol conversion of 52% with 93−94% selectivity toward propylene glycol were obtained.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8011424

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1831–1839

Titre :	Strong organic acids as efficient catalysts for the chloromethylation of m-xylene : the synthesis of 1,3-bis(chloromethyl)-4,6-dimethylbenzene
Type de document :	texte imprimé
Auteurs :	Tohru Kishida, Auteur ; Noboru Ieda, Auteur ; Takayoshi Yamauchi, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1831–1839
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Strong organic acids M-xylene chloromethylation Aqueous biphasic conditions
Résumé :	Strong organic acids, CCl3COOH, CHCl2COOH, CF3COOH, CH3SO3H, CF3SO3H, and p-CH3C6H4SO3H, effectively catalyzed the chloromethylation of m-xylene with hydrochloric acid and trioxane under organic and aqueous biphasic conditions. They were active enough at 2−10 wt % against m-xylene to yield chloromethyl-2,4-dimethylbenzene (I) and 1,3-bis(chloromethyl)-4,6-dimethylbenzene (II), although they accompanied trischloromethylation products, trischloromethyl-1,3-dimethylbenzenes (III). The highest yield of II, as high as around 70%, was obtained by using CF3SO3H under appropriate conditions because it has the strongest acid strength among the acids. These acids stay in aqueous phase after the catalysis, and organic products are easily separated from the reaction mixture. The reaction may start the formation of chloromethanol from formaldehyde, and strong organic acids can assist the stabilization of chloromethyl carbocation−acid complex formed by the dehydration of chloromethanol. The resulting complex gives I by nucleophilic attack at o- and p-positions of methyl groups, and II is formed through consecutive attack of the complex against I. The chloromethylation of biphenyl (BP) in the presence of strong acids also gave the chloromethylated products; however, large amounts of acid are necessary for the efficient formation of the products due to the low reactivity of BP.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8014022

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1824–1830

Titre :	Highly active and selective nanoalumina-supported wilkinson’s catalysts for hydroformylation of styrene
Type de document :	texte imprimé
Auteurs :	Peng Li, Auteur ; Warintorn Thitsartarn, Auteur ; Sibudjing Kawi, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1824–1830
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Nano-Al2O3 particles Polyamidoamine dendrimers Wilkinson’s catalyst
Résumé :	Uniform nano-Al2O3 particles were functionalized with surface amine ligands to form G0/nano-Al2O3 (where G stands for dendrimer generation) and then grafted with first generation PAMAM (polyamidoamine) dendrimers to form G1/nano-Al2O3. G0/nano-Al2O3 and G1/nano-Al2O3 were used to tether Wilkinson’s catalyst (RhCl(PPh3)3) to produce heterogenized rhodium complex catalysts, named respectively as Rh/G0/nano-Al2O3 and Rh/G1/nano-Al2O3. Both Rh/G0/nano-Al2O3 and Rh/G1/nano-Al2O3 catalysts show much higher activity and selectivity for hydroformylation of styrene than RhCl(PPh3)3 anchored on supports such as α-Al2O3, γ-Al2O3, and SBA-15. An increase of regioselectivity was observed from Rh/G0/nano-Al2O3 to Rh/G1/nano-Al2O3, showing the positive dendrimer effect on promoting the selectivity of styrene hydroformylation.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800715k

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1816–1823

Titre :	Catalytic synthesis of glycerol monoacetate using a continuous expanded bed column reactor packed with cation-exchange resin
Type de document :	texte imprimé
Auteurs :	Takuya Fukumura, Auteur ; Takuji Toda, Auteur ; Yuichiro Seki, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1816–1823
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Monoacetin Expanded-bed column reactor Acetic glycerol Acetic acid Glycerol Eley-Rideal-type catalytic reaction model
Résumé :	The selective and continuous production of monoacetin using an expanded-bed column reactor, in which the reactive fluid flows vertically upward and the catalyst is hydrodynamically floated, was studied. Acetic acid and glycerol were used as the substrates and the proton-type cation-exchange resin Amberlyst 16 was used as the catalyst. Batch reaction experiments under various conditions were first conducted to investigate the details of the heterogeneous catalytic reaction mechanism. The esterification of acetic acid with glycerol to produce the target product monoacetin was proved to proceed predominantly over the undesired consecutive esterification reactions to diacetin and triacetin. The intraparticle and extraparticle mass-transfer resistances for the catalytic resin were negligible. The Eley−Rideal-type catalytic reaction model was successfully applied to the experimental data for the various conditions. Next, the hydrodynamic correlation between the flow rate of the reactive fluid and the corresponding expanded-bed height on the continuous reactor was determined experimentally. Furthermore, the reaction and transport model for a continuous expanded-bed column reactor was constructed based on the kinetic model for the batch system. The numerical calculation simulated the experimental data well, and the optimum operating conditions were successfully determined by the theoretical analysis.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800625g

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1804–1815

Titre :	Modeling temperature profiles of a catalytic autothermal methane reformer with nickel catalyst
Type de document :	texte imprimé
Auteurs :	Diego Scognamiglio, Auteur ; Lucia Russo, Auteur ; Pier Luca Maffettone, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1804–1815
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	One-dimensional heterogeneous model Autothermal methane Fixed-bed reactor Kinetic modelSteam-to-methane ratios
Résumé :	In this work, a one-dimensional heterogeneous model for the autothermal reforming of methane in a catalytic (Ni/Al2O3 catalyst) fixed-bed reactor is proposed. The kinetic model implements an indirect reaction scheme and includes a reduction factor that is dependent on the oxygen concentration. Such a factor delays the reforming and water-gas shift reactions, with respect to the oxidation reactions. Experiments at different steam-to-methane ratios and feed flow rates were conducted in a small-scale reactor to identify and validate the proposed mathematical model. To this end, temperature profiles in the solid phase were measured with an infrared camera. The agreement between experimental data and model predictions is very good for all the investigated operating conditions. In particular, the model predicts the strong separation between the oxidation and the experimentally observed reforming zones well.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800518e

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1797–1803

Titre :	Desulfurization of vacuum gasoil by MCM-41 supported molybdenum-nickel catalysts
Type de document :	texte imprimé
Auteurs :	Tzong-Rong Ling, Auteur ; Ben-Zu Wan, Auteur ; Hong-Ping Lin, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1797–1803
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Vacuum gas oil Hydrodesulfurization Trickle bed reactor Scanning electron microscopy Temperature programming reduction X-ray diffraction
Résumé :	Hydrodesulfurization (HDS) of vacuum gas oil (VGO) was carried out in a trickle bed reactor at 400 °C and 7.2 MPa with a weight hourly space velocity (WHSV) = 2 h−1 over a series of molybdenum−nickel catalysts, which were prepared by loading the same amounts of MoO3 (12 wt %) and NiO (3 wt %) on supports including: tubular shaped MCM-41, nontubular shaped MCM-41, alumina, and silica. The HDS activity of the MoNi catalysts with different supports was investigated. The tubular shaped MCM-41, which possesses a regularly ordered molecular sieve structure, was shown to give significant improvements in the diffusion of large molecules. The results indicated that the tubular shaped MCM-41 supported catalyst has a higher activity than the other catalysts when measured over a 4−5 day running period. The effect of Si/Al ratios in the framework is also discussed. Various methods and techniques were used to characterize the catalysts such as: scanning electron microscopy (SEM), transmission electronic microscopy (TEM), temperature programming reduction (TPR), X-ray diffraction (XRD), mercury-porosity, and the generation of nitrogen adsorption−desorption isotherms.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8014389

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1786–1796

Titre :	Bubble size distribution for a bubble column reactor undergoing forced oscillations
Type de document :	texte imprimé
Auteurs :	Y. G. Waghmare, Auteur ; C. A. Dorao, Auteur ; H. A. Jakobsen, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1786–1796
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Oscillations Bubble size distribution Air-water system Breakage models
Résumé :	It has recently been shown that low amplitude (0.5−2.5 mm) oscillations at low frequencies (10−25 Hz) can be used to improve bubble column performance. Here, we report the study of bubble size distribution (BSD) in an oscillating bubble column for the air−water system. BSD was measured at different heights in the column, and the effects of various operating parameters such as frequency, amplitude, and gas flow rate were studied. Sauter mean diameter was calculated from BSD data, and it was correlated as a function of power input per unit mass using the Hinze formula. Population balance modeling simulations were performed. Two different breakage models (Martinez−Bazan and Luo−Svendsen) were considered which differ fundamentally in the constitution of the models and as a result predict opposite shapes of daughter size distribution curves. Simulation results were compared against experimental data, and both the models gave good comparisons with the measured Sauter mean bubble diameters. The predictions obtained from the simulation for BSD using the Martinez−Bazan model were in quantitative agreement with the experimental observations suggesting vibrations produce nearly equal size bubble breakage.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801375h

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1772–1785

Titre :	A simplified three-way catalyst model for transient hot-mode driving cycles
Type de document :	texte imprimé
Auteurs :	Dimitrios N. Tsinoglou, Auteur ; Martin Weilenmann, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1772–1785
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Three-way catalytic converters Real-world driving cycles Oxygen storage Heat transfer Mass transfer
Résumé :	Numerous models for the simulation of chemical phenomena in three-way catalytic converters (3WCCs) have been proposed in the literature, ranging from models of the detailed mechanism of the catalytic reactions on the surface to purely empirical correlations for the pollutant conversion efficiency. The application of these models for transient exhaust-gas conditions, such as real-world driving cycles, usually involves a tradeoff between the chemical background of the model, on one hand, and the computational load and ease of model parametrization on the other. In this work, a simplified mathematical model to simulate pollutant conversion in three-way catalytic converters is developed, that has a low computational load and ease of parametrization as primary priorities, but without completely disregarding the chemical background. The intended application of this model is the simulation of pollutant emissions from pilot fleets of vehicles, under real-world driving cycles, starting with a hot engine. Its main novelty is that it models the complex chemical phenomena in a 3WCC almost entirely on the basis of oxygen storage and release dynamics. One-dimensional simulation of the heat- and mass-transfer phenomena is also included in the model, based on well-established approaches from the literature. The model is validated against a large database of measured driving cycles, performed with different types of passenger cars. It is found to present an acceptable degree of correlation between simulated and experimental results, in terms of both instantaneous and cumulative pollutant emissions.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8010325

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1761–1771

Titre :	Production of norfloxacin nanosuspensions using microfluidics reaction technology through solvent/antisolvent crystallization
Type de document :	texte imprimé
Auteurs :	Thomai Panagiotou, Auteur ; Steven V. Mesite, Auteur ; Robert J. Fisher, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1761–1771
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Norfloxacin nanosuspensions Microfluidics reaction technology Crystalline structure
Résumé :	Hydrophobic active pharmaceutical ingredients (APIs) are often difficult to deliver effectively because of formulation limitations. Nanosuspensions of such drugs may be used to increase bioavailability and offer a variety of delivery options including injection, inhalation, oral, and transdermal. Microfluidics reaction technology (MRT) was used successfully to produce submicrometer API suspensions via a continuous process that involves solvent/antisolvent crystallization. As proof of concept, nanosuspensions of norfloxacin (NFN), an antibacterial agent, were produced varying the key parameters of the technology. The nanosuspensions had narrow particle size distributions and median particle sizes in the range of 170−350 nm. The particle size depends on the supersaturation ratio and energy dissipation expressed as processing pressure. However, the particle size was found to be insensitive to the presence of the surfactant used. The crystalline structure of NFN was not affected by the mixing intensity but by the solvent/antisolvent system. This “bottom up” process for creating nanosuspensions was compared to a “top down” process, in which NFN nanosuspensions were created as a result of particle size reduction. It was found that the “bottom up” process was substantially more efficient and resulted in smaller particles than the “top down” process. MRT is based on an impinging jet reactor design with jet velocities and energy dissipation that is orders of magnitude higher than those of conventional impinging jet reactors. The technology provides precise control of the feed rates and the subsequent location and intensity of mixing of the reactants. It may be the best choice economically due to its process intensification character that minimizes energy requirements and the proven scalability of the reactor.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800955t

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1749–1760

Titre :	Millisecond production of hydrogen from alternative, high hydrogen density fuels in a cocurrent multifunctional microreactor
Type de document :	texte imprimé
Auteurs :	Niket S. Kaisare, Auteur ; Georgios D. Stefanidis, Auteur ; Dionisios G. Vlachos, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1749–1760
Note générale :	Chemical enginnering
Langues :	Anglais (eng)
Mots-clés :	Pseudo-2-dimensional model Hydrogen Catalytic ammonia Platinum
Résumé :	A pseudo-2-dimensional model is used for modeling a multifunctional microreactor for hydrogen generation by coupling catalytic ammonia decomposition on ruthenium with catalytic propane combustion on platinum. The two reactions are carried out in adjacent parallel plate channels in a cocurrent flow mode. Operating lines defining the attainable region are computed. The high temperatures and fast heat transfer ensure that both reactions go to completion in as low as submillisecond contact times and enable compact hydrogen production for portable and distributed power generation. The ammonia decomposition reaction tends to be limited by the intrinsic rate of reaction, whereas catalytic combustion is also affected by mass and heat diffusion. We have found that moderate and high conductivity materials are preferable because they support a rather wide attainable region. We show that one such device could enable variable hydrogen supply for variable power needs. A simple operating strategy to dial in the desirable power is proposed, which ensures high thermal efficiency (∼75% once-through efficiency of the integrated device and ∼85% reformer efficiency, both without any heat recuperation), wall isothermicity, and high conversions.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800392z

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1740–1748

Titre :	Numerical simulation of trickle-bed reactor hydrodynamics with RANS-based models using a volume of fluid technique
Type de document :	texte imprimé
Auteurs :	Rodrigo J. G. Lopes, Auteur ; Rosa M. Quinta-Ferreira, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1740–1748
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Trickle-bed reactor Volume of fluid model Fluid dynamics Hydrodynamic behavior
Résumé :	A trickle-bed reactor (TBR) was modeled by means of the volume of fluid (VOF) model to provide a hydrodynamic behavior analysis in trickling flow conditions. Fluid dynamics of the TBR is characterized by poor liquid distribution and inefficient catalyst utilization and conventional modeling techniques are unable to address these key design issues. Therefore, the VOF code was used to investigate the major hydrodynamic parameters in a three-dimensional packed bed providing a more rigorous physical description of the underlying flow process. Several numerical solution parameters including different mesh densities, time steps, and convergence criteria were optimized in order to provide computational independent results. During the parametric optimization it was found that the VOF model is more sensible to mesh density and time step than with respect to convergence criteria. The computational fluid dynamic model was thoroughly validated by comparing the model predictions with the published experimental data for liquid holdup and two-phase pressure drop. After the VOF optimization, selected values for the numerical solutions parameters were used to perform the assessment of different turbulent flow models at two nominal gas flow rates. Afterward, several computational runs were performed in the evaluation of the influence of either gas or liquid flow rate on TBR hydrodynamics.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8014186

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1735–1739

Titre :	Efficient methylene blue removal over hydrothermally synthesized starlike BiVO4
Type de document :	texte imprimé
Auteurs :	Songmei Sun, Auteur ; Wenzhong Wang, Auteur ; Lin Zhou, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1735–1739
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Starlike BiVO4 Water/ethanol mixture Ethylenediamine tetraacetic acid
Résumé :	Nanoplate-stacked starlike BiVO4 products have been successfully synthesized by a hydrothermal method, where a water/ethanol mixture was the solvent and ethylenediamine tetraacetic acid (EDTA) was the chelating agent. The molar ratio of EDTA to Bi3+ was found to play an important role in the formation of this morphology. These starlike BiVO4 samples exhibited a high visible-light-driven photocatalytic efficiency. For the degradation of methylene blue (MB) under visible-light irradiation (λ > 420 nm), about 91% of the MB was degraded within 25 min. This is much higher than for BiVO4 samples prepared by solid-state reaction (bulk BiVO4) and other hydrothermal synthesis methods. The reasons for the differences in the photocatalytic activities of these BiVO4 samples were further investigated.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801516u

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1727–1734

Titre :	Exploring the water-soluble phosphine ligand as the environmentally friendly stabilizer for electroless nickel plating
Type de document :	texte imprimé
Auteurs :	Ke Wang, Auteur ; Liang Hong, Auteur ; Zhao-Lin Liu, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1727–1734
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Phosphine compounds Nickel atom Water-soluble phosphine Electroless nickel plating
Résumé :	Phosphine (R3P) compounds being a typical type of coordination ligand used in homogeneous catalysis are known to possess a tunable affinity with the nickel atom. As such, it deserves to be studied whether a water-soluble phosphine ligand could also be used as a plating stabilizer in the electroless nickel plating (ENP) system in place of hazardous Pb(II) salt and what will be the unique effects generated due to this replacement. Triphenylphosphine-3,3′,3′′-trisulfonic acid trisodium salt (TPPTS) was then chosen as a model phosphine stabilizer to perform the study. TPPTS could indeed work to prevent the ENP process from running out of control. In addition, unlike the existing ENP stabilizers, TPPTS does not reveal a percolation concentration for a sharp ceasing of plating. Also according to the voltammetry investigation, TPPTS can be classified as a cathodic stabilizer. A Ni−P plating layer with high phosphorus content (>15%) has been achieved using10−4 mol/L TPPTS in the plating bath. Furthermore, this work investigated the relation between P weight percent and corrosion resistance of either the as-plated or the annealed Ni−P plating layer by electrochemical impedance spectroscopy (EIS). The annealing was found, according to the depth profile analysis, to drive diffusion of both Ni and P toward the bulk phase, which strongly revamps corrosion resistance of the plating layer. Finally, the stability of the ENP bath was evaluated using the metal-turnover (MTO) test.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801456f

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1719–1726

Titre :	Optimization of base catalytic methanolysis of sunflower (helianthus annuus) seed oil for biodiesel production by using response surface methodology
Type de document :	texte imprimé
Auteurs :	Umer Rashid, Auteur ; Farooq Anwar, Auteur ; Muhammad Arif, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1719–1726
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Response surface methodology Sunflower Crude oilMethanolysis
Résumé :	In the present work, the response surface methodology (RSM), based on a central composite rotatable design (CCRD), was used to determine the optimum conditions for the methanolysis of sunflower (Helianthus annuus) crude oil. Four process variables were evaluated at two levels (24 experimental design): the methanol/oil molar ratio (3:1−9:1), the catalyst concentration in relation to the oil mass (0.2−1.2 wt % KOH), the reaction temperature (35−65 °C), and the alcoholysis reaction time (10−120 min). Using RSM, a quadratic polynomial equation was obtained by multiple regression analysis for predicting the optimization of the transesterification reaction. The results indicated that the methanol-oil-molar ratio, catalyst concentration, and reaction temperature were the significant parameters affecting the yield of sunflower oil methyl esters (SOMEs/biodiesel). The optimum transesterification reaction conditions, established using RSM, which offered 97.8% SOME yield, were found to be 6.0:1.0 methanol-to-oil ratio, 0.70% catalyst concentration, 50 °C reaction temperature, and 65-min reaction time. The proposed process provided an average biodiesel yield of more than 91%. A linear relationship was constructed between the observed and predicted values of yield. The biodiesel produced in the present experiments was analyzed by gas chromatography (GC), which showed that it mainly contained four fatty acid methyl esters (linoleic, oleic, palmitic, and stearic acids). The nuclear magnetic resonance (1H NMR) spectrum of the SOMEs is also reported. The fuel properties of the SOMEs such as density, cetane number, kinematic viscosity, oxidative stability, lubricity, cloud point, pour point, cold filter plugging point, flash point, ash content, sulfur content, acid value, copper strip corrosion value, and higher heating value were determined and are discussed in light of biodiesel standards ASTM D6751 and EN 14214.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801136h

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1712–1718

Titre :	Photocatalytic and thermal degradation of poly(methyl methacrylate), poly(butyl acrylate), and their copolymers
Type de document :	texte imprimé
Auteurs :	Vinod Kumar Konaganti, Auteur ; Giridhar Madras, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1712–1718
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Poly(methyl methacrylate) Poly(butyl acrylate) Photocatalytic degradation Thermal degradation o-dichlorobenzene Copolymers
Résumé :	The photocatalytic and thermal degradations of poly(methyl methacrylate), poly(butyl acrylate), and their copolymers of different compositions were studied. The photocatalytic degradation was investigated in o-dichlorobenzene in the presence of two different catalysts, namely, Degussa P-25 and combustion synthesized nanotitania (CSN-TiO2). The samples were analyzed by using gel permeation chromatography (GPC) to obtain the molecular weight distributions (MWDs) as a function of reaction time. Experimental data indicated that the photodegradation of these polymers occurs by both random and chain end scission. A continuous distribution kinetic model was used to determine the degradation rate coefficients by fitting the experimental data with the model. Both the random and specific rate coefficients of the copolymers decreased with increasing percentage of butyl acrylate (BA). Thermal degradation of the copolymers was investigated by thermogravimetry. The normalized weight loss profiles for the copolymers showed that the thermal stability of the copolymers increased with mole percentage of BA in the copolymer (PMMABA). The Ozawa method was used to determine the activation energies at different conversions. At low acrylate content in the copolymer, the activation energy depends on conversion, indicating multiple degradation mechanisms. At high acrylate content in the copolymer, the activation energy is independent of conversion, indicating degradation by a one-step mechanism.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801646y

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1706–1711

Titre :	Synthesis and properties of poly(ester urethane)s consisting of poly(l-lactic acid) and poly(ethylene succinate) segments
Type de document :	texte imprimé
Auteurs :	Jian-Bing Zeng, Auteur ; Yi-Dong Li, Auteur ; Wen-Da Li, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1706–1711
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Poly(ester urethane) Chain-extension reaction Poly(l-lactic acid) Poly(ethylene succinate) Polymerization
Résumé :	An aliphatic polyester based poly(ester urethane) (PEU) consisting of poly(l-lactic acid) and poly(ethylene succinate) was successfully prepared via chain-extension reaction of poly(l-lactic acid)-diol (PLLA-OH) and poly(ethylene succinate)-diol (PES-OH) using 1,6-hexamethlyene diisocyanate (HDI) as a chain extender. PLLA-OH was obtained by direct polycondensation of l-lactic acid in the presence of 1,4-butanediol. PES-OH was synthesized by condensation polymerization of succinic acid with excessive ethylene glycol. The structures and molecular weights of PLLA-OH, PES-OH, and PEUs were characterized by proton nuclear magnetic resonance (1H NMR), Fourier transform infrared (FTIR), and gel permeation chromatography (GPC). The PEUs were further studied by the means of thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and tensile testing. The data of GPC analysis indicated that high molecular weights for example more than 200 000 g·mol−1 were easily synthesized through chain-extension reaction. The PEUs synthesized with high molecular weight and excellent tensile properties could find some applications in biomaterials and environmental friendly materials.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801391m

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1699–1705

Titre :	Win-win coupling in electrodialysis with bipolar membranes (EDBM) for cleaner production
Type de document :	texte imprimé
Auteurs :	Chuanhui Huang, Auteur ; Tongwen Xu, Auteur ; Haozhe Feng, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1699–1705
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Electrodialysis Bipolor membranes Piperazine sulfate Sodium gluconate
Résumé :	An obstacle to the development of electrodialysis with bipolor membranes (EDBM) technology—high fixed cost—can be cleared away by allocating the investment among factories or plants, but it requires that EDBM couple two processes inside and provide respective products cost-effectively. To assess the process coupling, piperazine sulfate (PzH2SO4) and sodium gluconate (NaGlu) were used as model agents for Pz regeneration and HGlu production, respectively. The results showed that the highest current efficiency was achieved at the highest current density, and the lowest energy consumption at the highest feed concentration. The process cost was estimated to be $0.80 kg−1 Pz and $0.17 kg−1 HGlu in the coupled operation, which were less than those in separate operations—$0.96 kg−1 Pz and $0.24 kg−1 HGlu. Apart from environmental benignity, the process coupling in EDBM can achieve a win−win economy due to allocation of investment and economies of scale.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801192k

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1694–1698

Titre :	Zirconium hydroxide as a reactive substrate for the removal of sulfur dioxide
Type de document :	texte imprimé
Auteurs :	Gregory W. Peterson, Auteur ; Christopher J. Karwacki, Auteur ; William B. Feaver, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1694–1698
Note générale :	Chemical enineering
Langues :	Anglais (eng)
Mots-clés :	Zirconium hydroxide Sulfur dioxide Temperature-programmed desorption X-ray photoelectron spectroscopy
Résumé :	Zirconium hydroxide [Zr(OH)4], with a surface area of 365 m2/g, was evaluated for its ability to remove SO2 from streams of air at room temperature. The SO2 removal capacity of Zr(OH)4 was ∼90 mg SO2 removed per cm3 bed volume, which is almost an order of magnitude greater than the value achieved for activated carbon and is more than twice the value achieved for activated carbon impregnated with 10% CuO. Temperature-programmed desorption results indicate that SO2 is strongly retained by Zr(OH)4. X-ray photoelectron spectroscopy results reveals the presence of sulfite (SO32−) species following reaction exposure, which suggests the formation of zirconium sulfite. Although the SO2 removal capacity (volume basis) of Zr(OH)4 is high, relative to that of impregnated activated carbon, only 10% of the stoichiometric hydroxyl groups are able to contribute to the removal of SO2.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801403h

[article]
in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1683–1693

Titre :	Attribute-based modeling of resid structure and reaction
Type de document :	texte imprimé
Auteurs :	Darin M. Campbell, Auteur ; Craig Bennett, Auteur ; Zhen Hou, Auteur
Année de publication :	2009
Article en page(s) :	pp. 1683–1693
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Feedstock structure Monte Carlo simulation Molecular structures Probability density functions
Résumé :	An attribute-based approach to modeling resid structure and reaction is described. Monte Carlo simulation of feedstock structure casts the modeling problem in molecular terms. This technique samples probability density functions (PDFs) for the attributes of the resid molecular structures to construct a representative molecular sample whose properties are compared against measured properties. Optimization methods are used to minimize the weighted sum of squares difference, and the final set of PDF parameters are the mathematical representation of resid structure. Subsequent reaction models can be based on the molecular attributes of the PDFs. The latter model, which is called the “Attribute Reaction Model” (ARM), provides a large reduction in the number of reaction equations and, therefore, solution time. The combined structural and reaction model provides a very good representation of laboratory data for four resids.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8012314

Industrial & engineering chemistry research / Paul, Donald R. . Vol. 48 N°4

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