Catalogue en ligne Bibliothèque Ecole Nationale Polytechnique d'Alger

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 929–932

Titre :	Prediction of triple-point temperature of pure components using their Chemical Structures
Type de document :	texte imprimé
Auteurs :	Gharagheizi, Farhad, Auteur ; Sattari, Mehdi, Auteur
Année de publication :	2010
Article en page(s) :	pp 929–932
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Triple-point temperature Chemical structures.
Résumé :	A quantitative structure property relationship study was performed to develop a model for the prediction of triple-point temperature of pure components. For developing this model, 638 pure components were used, and, for whichever, 1664 molecular descriptors were determined. As a standard tool for subset variable selection, genetic algorithm-based multivariate linear regression (GA-MLR) technique was used. The obtained model is a seven parameters multilinear equation that has a squared correlation coefficient of 0.9410 (R2 = 0.9410).
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901029m

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 925–928

Titre :	Phase equilibria of methane hydrates in the presence of methanol and/or ethylene glycol aqueous solutions
Type de document :	texte imprimé
Auteurs :	Amir H. Mohammadi, Auteur ; Richon, Dominique, Auteur
Année de publication :	2010
Article en page(s) :	pp 925–928
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Methane Hydrates Phase equilibria Ethylene glycol Aqueous solutions.
Résumé :	In this communication, experimental dissociation data for methane hydrates in the presence of 0.042 mass fraction methanol aqueous solution and/or 0.069 mass fraction ethylene glycol aqueous solution are first reported. The experimental data were generated using an isochoric pressure-search method. The experimental dissociation data for methane hydrates in the presence of 0.042 mass fraction methanol aqueous solution or 0.069 mass fraction ethylene glycol aqueous solution are successfully compared with the predictions of a thermodynamic model to demonstrate its reliability for low concentrations of methanol or ethylene glycol in aqueous solution. The model predictions are then compared with the experimental data for the methanol + ethylene glycol aqueous solution system to study its reliability. We finally report experimental dissociation data for methane hydrates in the presence of 0.1, 0.2, 0.35, and 0.5 mass fraction methanol or ethylene glycol aqueous solutions with the aim of studying the reliability of corresponding experimental data reported in the literature and the predictions of the thermodynamic model.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901357m

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 920–924

Titre :	Solvent-free fabrication of ferromagnetic Fe3O4 octahedra
Type de document :	texte imprimé
Auteurs :	Pol, Vilas G., Auteur ; Daemen, Luke L., Auteur ; Vogel, Sven, Auteur
Année de publication :	2010
Article en page(s) :	pp 920–924
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Solvent-free Ferromagnetic Fe3O4 Octahedra.
Résumé :	The controlled thermolysis of a presynthesized single precursor, Fe3(CH3COO)6(OH)2CH3COO, in a closed reactor at 700 °C in an inert atmosphere produced ferromagnetic Fe3O4 octahedra without using solvent or catalyst. The octahedral shape with the 6−10 μm diameter of Fe3O4 is realized using field emission scanning electron microscope, and the composition, with an attached energy dispersive X-ray analyzer. The single-crystalline face-centered cubic structure of Fe3O4 octahedra is analyzed by X-ray diffraction measurements, further supported by Raman spectroscopy and transmission electron microscopy. The thermogravimetric analysis measured the amount of carbon present on the Fe3O4 octahedra surfaces. The vibrating magnetometer corroborated ferromagnetic behavior of Fe3O4 octahedra with 150 Oe coercive force, 48 emu/g saturation magnetization, and 5 emu/g remnent magnetization.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9011062

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 913–919

Titre :	Optimal experimental design for discriminating numerous model candidates : the AWDC criterion
Type de document :	texte imprimé
Auteurs :	Michalik, Claas, Auteur ; Stuckert, Maxim, Auteur ; Marquardt, Wolfgang, Auteur
Année de publication :	2010
Article en page(s) :	pp 913–919
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Optimal experimental Discriminating numerous.
Résumé :	While model-based optimal experimental design (OED) strategies aiming at maximizing the parameter precision are regularly applied in industry and academia, only a little attention has been payed to OED techniques for model discrimination in practical applications. A broader use of these techniques is mainly hindered by two drawbacks: (i) The use of such techniques is desirable in an early model identification phase, where only a little knowledge on the process is available. The known methods, however, rely on good estimates of the parameters of all candidate model structures. (ii) The available methods are tailored to few (ideally two) model candidates and do not work well if numerous candidate structures are taken into account. In this work we propose a novel design criterion for model-based OED for model discrimination in the case of multiple model candidates. The resulting OED method is thus well-suited for designing experiments in an early stage of the model identification process to efficiently reduce the number of model candidates, thereby reducing the overall cost for model identification.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900903u

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 900–912

Titre :	Quantitative structure−property relationships for prediction of phase equilibrium related properties
Type de document :	texte imprimé
Auteurs :	Shacham, Mordechai, Auteur ; Cholakov, Georgi St., Auteur ; Stateva, Roumiana P., Auteur
Année de publication :	2010
Article en page(s) :	pp 900–912
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Predicting vapor Binary interaction Homologous series Structure property Phase equilibrium.
Résumé :	In this work, novel techniques for predicting vapor pressure and binary interaction coefficients for homologous series are developed based on the previously proposed targeted quantitative structure−property relationship (TQSPR) and QS2PR methods. For predicting vapor pressure variation as a function of temperature, a two-reference compound (TRC) QSPR method is suggested. This method uses two, structurally similar predictive compounds with available vapor pressure data to predict point by point the vapor pressure or the saturation temperature of a target compound. For the target compound, only structural information is required. The two variants of the method were applied to several homologous series. They demonstrate prediction of vapor pressure within experimental uncertainty, depending on the level of similarity between the predictive compounds and the target compound. A targeted QSPR method for prediction of the binary interaction coefficients (kij) in cubic equations of state for a compound with the members of its homologous series is also presented. The coefficients for the Soave−Redlich−Kwong and Peng−Robinson equations, used to test the method, were reproduced within the deviation of those obtained from regressed experimental data.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900807j

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 893–899

Titre :	Experimental and numerical investigations of two-phase (Liquid−Liquid) flow behavior in rectangular microchannels
Type de document :	texte imprimé
Auteurs :	Reddy Cherlo, Siva Kumar, Auteur ; Kariveti, Sreenath, Auteur ; S. Pushpavanam, Auteur
Année de publication :	2010
Article en page(s) :	pp 893–899
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	kinetics Mass-transfer Multiphase microreactors Two phase liquid Rectangular microchannels.
Résumé :	The interaction between kinetics and mass-transfer effects is determined by the flow regime in liquid−liquid multiphase microreactors. The operating conditions under which the various flow regimes such as slug flow and stratified flow occur in liquid−liquid systems has not been extensively studied and is not well-understood. The effect of operating conditions on slug length for instance is not well-known. The present study focuses on microreactors fabricated in Perspex (poly(methyl methaacrylate) (PMMA)), which are essentially microchannels with a rectangular cross-section. Experiments are carried out for a wide range of flow rates, channel sizes, and fluid systems with varying properties. Two different kinds of flow regimes, slug flow and stratified flow, are experimentally observed, and these are predicted using numerical simulations. We divide the space of operating conditions (the two liquid flow rates) into different regions such that in each region the flow regime is distinct. The dependence of slug length on flow rates and other parameters such as channel size, viscosity, surface tension, and contact angle have been determined and are quantitatively compared with predictions of simulations.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900555e

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 887–892

Titre :	Water sorption isotherms of NPK 10−20−20/4 muriate of potash fertilizer
Type de document :	texte imprimé
Auteurs :	Barreiro, José A., Auteur ; Andreina Minichini, Jr., Auteur ; Sandoval, Aleida J., Auteur
Année de publication :	2010
Article en page(s) :	pp 887–892
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Water Isotherms Potash Fertilizer.
Résumé :	Water sorption isotherms of NPK 10−20−20/4 muriate of potash (MOP) fertilizer were determined using a gravimetric method for temperatures ranging from 15 to 35 °C. It was found that the sorption behavior of the fertilizer assimilated to a type-III isotherm characteristic of crystalline solids. The sorption data could be represented by a single isotherm in the temperature range studied. The equilibrium data obtained were fitted to two-parameter linearized and nonlinear three- and four-parameter models. Among the models studied, the nonlinear three-parameter Guggenheim−Anderson−De Boer (GAB) model was selected. This equation allowed the calculation of a monolayer water content of 0.852 g of water/100 g of dry solids, and monolayer and multilayer water sorption enthalpy values of HN = 43.3 kJ/gmol and HM = 44.2 kJ/gmol, respectively.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900533q

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 876–886

Titre :	Fragment-based approach for estimating thermophysical properties of fats and vegetable oils for modeling biodiesel production processes
Type de document :	texte imprimé
Auteurs :	Ramanathan, Sundaram, Auteur ; Chau-Chyun Chen, Auteur
Année de publication :	2010
Article en page(s) :	pp 876–886
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Estimating thermophysical Vegetable Oils Biodiesel production.
Résumé :	A fragment-based methodology for estimating the thermophysical properties of triglycerides is presented. In contrast to the commonly practiced functional group estimation approach, the proposed methodology adopts a chemical constituent fragment-based approach to estimate the triglyceride pure component properties from fragment composition and parameters of the fragments. The fragment-specific parameters are obtained from regressing against very limited experimental data for triglycerides available in the literature. The methodology further explores the relationships between carbon atom numbers of fatty acid constituent fragments and the values of these fragment-specific parameters. Additionally, the effect of the double bonds on the values of these fragment-specific parameters is investigated. Based on this methodology, we develop the first-ever pure component thermophysical property databank of triglycerides. We show satisfactory predictions on the properties of triglycerides, fats, and oils. We further show the superiority of this methodology over the traditional functional group approach. The methodology, the derived databank, together with the currently available databanks for fatty acids and corresponding esters, enable efficient and reliable thermophysical property calculations in support of process modeling, simulation, design, and optimization of biodiesel production processes.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900513k

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 870–875

Titre :	Fouling rate of calcium carbonate on the surface of sieve trays
Type de document :	texte imprimé
Auteurs :	Zhou, Aidong, Auteur ; Zhang, Zhibing, Auteur
Année de publication :	2010
Article en page(s) :	pp 870–875
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Calcium Carbonate Stimulating stage Declining stage Fouling process.
Résumé :	Fouling caused by the precipitation of calcium carbonate on the surfaces of sieve trays made of four kinds of materials was studied in a 100 mm diameter column. Tests were carried out within a Ca(OH)2−H2O−CO2−air system in the absence of impurity ions or inhibitors. The effects of suspension concentration, temperature, CO2-inlet concentration, F-factor, time, and tray material on the fouling rate were determined. XRD and SEM morphology showed that the fouling crystal is calcite. Experiments indicated that the whole fouling process mainly consisted of three rate stages, called the “stimulating stage - the first stage”, “declining stage - the second stage”, and “steady stage - the third stage”, respectively. On the basis of the experimental data, numerical equations describing the fouling process of the four trays are established and subsequently used to predict the fouling rates of the trays made of different materials.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900318c

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 859–869

Titre :	Computational modeling of cell growth heterogeneity in a perfused 3D scaffold
Type de document :	texte imprimé
Auteurs :	Flaibani, Marina, Auteur ; Magrofuoco, Enrico, Auteur ; Elvassore, Nicola, Auteur
Année de publication :	2010
Article en page(s) :	pp 859–869
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Cell heterogeneity Spatiotemporal evolution Computational model.
Résumé :	Our goal was to develop a computational model describing the spatiotemporal evolution of cell heterogeneity within a three-dimensional porous scaffold during cell growth in a perfusion bioreactor. The scaffold was assumed formed by an ensemble of independent parallel cylindrical channels with a defined diameter distribution. The total flow rate partitioning in each channel depends on the effective diameter, which is reduced by the cell growth on the channel wall. The mass balance for one metabolite and the cell volume balance were solved. For each channel diameter, the model simulation provide the spatiotemporal evolution of velocity, shear stress, metabolite concentration, and cell volume growth. In particular, all of these outcomes can be analyzed as a function of channel diameter providing an evaluation of cell property heterogeneity. The model describes that the cell growth can be substantially different in each channel diameter. For instance, in the small diameter channel, cell growth is limited by metabolite mass transport, whereas in the larger diameter channel, shear stress inhibits cell growth. This mathematical model could be an important tool for a priori estimation of the time variation of the cell volume fraction and its degree of heterogeneity as a function of operational parameters and scaffold pore size distribution.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900418g

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 852–858

Titre :	Myco-crystallization of silver Ions to nanosized particles by li ve and dead cell filtrates of aspergillus oryzae var. viridis and Its bactericidal activity toward staphylococcus aureus KCCM 12256
Type de document :	texte imprimé
Auteurs :	Binupriya, Arthur Raj, Auteur ; Sathishkumar, Muthuswamy, Auteur ; Yun, Soon-Il, Auteur
Année de publication :	2010
Article en page(s) :	pp 852–858
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Silver ions Crystalllization Cell filtrates Aspergillus oryzae.
Résumé :	Crystalllization of silver ions to nanosized particles by cell filtrates from live and dead cell filtrates Aspergillus oryzae var. viridis (A. oryzae var. viridis) through bioreduction process was assessed. Strong plasmon resonance of silver nanoparticles was observed around 435 nm. Transmission electron microscopy (TEM), energy dispersive X-ray (EDX), and X-ray diffraction (XRD) were performed to examine the formation of silver nanoparticles. Comparing live and dead cell filtrates of A. oryzae var. viridis, the latter showed high silver nanoparticle productivity. The nanoparticles formed were quite uniform in shape and ranged in size from 5 to 50 nm. Organics from the dead cells are believed to be responsible for bioreduction of ionic silver to nanosized silver particles. Organic content of the dead cell filtrate was found to be double the amount of live cell filtrate. High productivity of silver nanoparticles by a metabolically independent process opens up an interesting area of nanoparticle synthesis using waste fungal biomass from industries. The minimum bactericidal concentration (MBC) for the Staphylococcus aureus KCCM 12256 strain was found to be 40 mg/L.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9014183

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 847–851

Titre :	Evaporative cooling of water in a rotating packed bed (Split Packing)
Type de document :	texte imprimé
Auteurs :	Bhattacharya, S., Auteur ; Mondal, A., Auteur ; Bhowal, A., Auteur
Année de publication :	2010
Article en page(s) :	pp 847–851
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Rotating packed bed Mass-transfer processes.
Résumé :	Rotating packed beds (RPB) have been studied for intensifying mass-transfer processes. This work was undertaken to evaluate the thermal performance of an RPB with split packing for evaporative cooling of water involving simultaneous heat and mass transfer. Higher efficiency was achieved within a smaller contactor volume compared to mechanical draft cooling towers. At all values of the liquid-to-air flow rate ratio studied, efficiency was not significantly affected by rotor speed and decreased with increasing rotor speed beyond a certain limit at low air and water flow rates. A simple mathematical model was used to estimate process parameters from the experimental data based on the Merkel assumption. The hGa/kYaCs ratio varied between 0.85 and 1.18, and the tower characteristic of the RPB was between 1.4 and 4.0.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901207m

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 838–846

Titre :	Investigation of simplifying assumptions in mathematical modeling of natural gas dehydration using adsorption process and introduction of a new accurate LDF model
Type de document :	texte imprimé
Auteurs :	Gholami, M., Auteur ; Talaie, M. R., Auteur
Année de publication :	2010
Article en page(s) :	pp 838–846
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Natural gas dehydration Adsorption process LDF model.
Résumé :	In this study, a comprehensive mathematical model was developed to investigate the simplifying assumptions in modeling of natural gas dehydration by the adsorption process. In the developed model the variations of pressure, velocity, and temperature along the bed and the temperature changes inside the particles were considered. Convective heat and mass transfer were considered outside the particles and a diffusion mechanism was taken into account for the heat and mass transfer inside the particles. A dual site Langmuir model was selected to predict adsorption equilibrium and the Peng−Robinson equation of state was used to calculate the gas compressibility factor. The experimental data of Mohamadinejad et al. [Mohamadinejad, H.; et al. Sep. Sci. Technol. 2000, 35, 1] was used to verify the model. Good agreement was observed between the predictions of the comprehensive model and the experimental data. The results showed that applying the assumptions of uniform temperature distribution inside the pellet (lump method), thermal equilibrium between gas and particles, and isothermal and isobaric conditions had no significant effects on the predictions. It was also concluded that external mass transfer resistance was negligible at the industrial operating conditions of gas dehydration processes and common linear driving force models (LDFs) were not able to predict the performance of the dehydration bed well. Also, a new accurate correlation was introduced for an LDF proportionality coefficient applicable in gas dehydration systems. The predictions based on the proposed correlation were in good agreement with the results of the comprehensive model. Using this new accurate LDF model instead of diffusion model saves a large amount of CPU time without a loss of accuracy.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901183q

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 822–837

Titre :	Exploring the essence of three-phase packed distillation : substantial mass transfer computation
Type de document :	texte imprimé
Auteurs :	Chen, Liang, Auteur ; Jens-Uwe Repke, Auteur ; Günter Wozny, Auteur
Année de publication :	2010
Article en page(s) :	pp 822–837
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Essence Mass transfer Vapor Liquid.
Résumé :	Three-phase packed distillation has been so far relatively poorly understood. Hence, a substantial mass transfer model describing the (vapor−liquid−liquid) three-phase flow in packed column is proposed to explore the essence of three-phase distillation. The model enables, for the first time, rigorous computation of all the interphase transfer parameters on the basis of a thorough consideration of the unique flow behaviors (such as film breakup, rivulet-flow, surface variation, etc.) caused by the second liquid. The derived theoretical mass transfer model has been incorporated into the three-phase nonequilibrium simulation. Moreover, comprehensive experimental investigations have been carried out using two laboratory-scale columns, and four different packings (Montz-Pak B1-350, Rombopak 9M, Raschig Super-Ring 0.3, and Sulzer Optiflow C.36) were considered. The derived experimental database, covering a wide range of load conditions, is used for flow pattern identification and model validation. For the studied n-butanol/water/n-propanol system, it is revealed that the flow pattern of the second liquid (aqueous phase) could play a critical role in the system performance. When the second liquid flows below the first liquid film, it will enlarge the interfacial area and enhance the vapor−liquid mass transfer; when the second liquid flows above the first liquid film, it will reduce the interfacial area and degrade the mass transfer. This fundamental flow behavior may essentially result in the discrepancy existing in the highly variable separation efficiencies in three-phase packed columns.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9010645

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 817–821

Titre :	Adsorption parameters of toluene on amberlite adsorbent for purification unit useful in vehicle application
Type de document :	texte imprimé
Auteurs :	Swesi, Yousef, Auteur ; Kerleau, Philippe, Auteur ; Lamotte, Violaine, Auteur
Année de publication :	2010
Article en page(s) :	pp 817–821
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Adsorbents Hydrogen purification Amberlite adsorbent Vehicle application.
Résumé :	This work focuses on the analysis of three types of adsorbents that can be used in hydrogen purification, for the supply of vehicle fuel cells. This technique uses several adsorption columns filled with an adsorbent to obtain continuous operation of the hydrogen production process. Among the three adsorbents tested, the experimental study leads to the choice of Amberlite XAD-4, which gives high adsorption capacity (up to 0.0620 kgTol·kgXAD−1) with good regeneration properties at low cost. Equilibrium data were fitted to the modified Drachsel isotherm equation. These data provide a useful reference in the design and assessment of the purification process.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900966p

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 809–816

Titre :	Effect of isomorphous metal substitution in zeolite framework on pervaporation xylene-separation performance of MFI-type zeolite membranes
Type de document :	texte imprimé
Auteurs :	O’Brien-Abraham, Jessica, Auteur ; Y. S. Lin, Auteur
Année de publication :	2010
Article en page(s) :	pp 809–816
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Isomorphous Metal Zeolite membranes.
Résumé :	MFI-type zeolite membranes have shown good selectivity for separation of p-xylene from its isomers. The major problem with the MFI-type zeolite membrane is that the MFI-type zeolite framework loses its size/shape selectivity under high loadings of p-xylene because of the significant framework distortion experienced by the pore structure and as a result observed high selectivities are not stable over time. This paper proposes changing the interaction of the xylene isomers with MFI-type framework to address this problem. MFI-type zeolite membranes with aluminum and boron isomorphously substituted into the framework were synthesized and subjected to multicomponent xylene separation via pervaporation. It is found that by performing this substitution, slight changes to both surface chemistry and framework flexibility can be introduced. Essentially, the interaction of the xylene molecules with the MFI structure is modified to limit p-xylene loading, as well as diffusion pathway access to o-xylene. As a result improvement in xylene separation performance over silicalite was observed. The boron-substituted membranes demonstrated the highest selectivities for p-xylene under a wide range of feed compositions; the highest selectivity observed was 55 (feed, 5% p-xylene; 95% o-xylene). This is higher than any previously reported xylene separation selectivity for pervaporation through MFI-type zeolite membranes. However, the performance stability of substituted membranes over time was also investigated, and it was found that, over a period of 96 h, a reduction in selectivity of about an order of magnitude was observed.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900926t

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 797–808

Titre :	Influence of KF and HF on the selectivity of Zr and Hf separation by fractional crystallization of K2Zr(Hf)F6
Type de document :	texte imprimé
Auteurs :	Branken, Dawie J., Auteur ; Lachmann, Gerhard, Auteur ; Krieg, Henning M., Auteur
Année de publication :	2010
Article en page(s) :	pp 797–808
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Crystallization KF Zirconium meta Nuclear characteristics Separation method.
Résumé :	For nuclear applications, zirconium metal (Zr) must adhere to stringent specifications, where a low hafnium (Hf) content, i.e., <100 ppm, is one of the most important requirements due to the opposing nuclear characteristics of the two elements. Hf-purified Zr is however not easily obtained, as the two entities occur together in nature and they are exceptionally difficult to separate due to their close chemical and physical similarities. In this study, cooling crystallization of K2Zr(Hf)F6 from aqueous solutions, i.e., fractional crystallization, was investigated as a separation method. The influence of the solvent composition on the selectivity of fractional crystallization as separation method was studied, wherein KF and HF were used as additives. Using scanning electron microscopy and X-ray diffraction analysis of the product crystals, it is shown that crystallization from KF solutions resulted in a decrease in the crystal size leading to the formation of K3Zr(Hf)F7 with increasing KF concentration. These effects resulted in a decreased selectivity, which was suppressed by the addition of 2.5 mol/L HF to the crystallization solution. In addition, it is shown that selectivity improved with an increasing relative excess amount of solute with respect to the solubility at the lower crystallization temperature, which could be favorably regulated by adjusting the KF concentration of a 2.5 mol/L HF solvent solution. Consequently, the most efficient separation was obtained using a solution consisting of 0.45 mol/L KF and 2.5 mol/L HF.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900747k

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 790–796

Titre :	Improved antifouling property of PES ultrafiltration membranes using additive of silica−PVP nanocomposite
Type de document :	texte imprimé
Auteurs :	Sun, Mengping, Auteur ; Su, Yanlei, Auteur ; Chunxia Mu, Auteur
Année de publication :	2010
Article en page(s) :	pp 790–796
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Silica PVP nanocomposite Hydrophilic additive PES ultrafiltration membranes.
Résumé :	To improve the surface coverage of polyvinylpyrrolidone (PVP) on membrane surfaces and further enhance the antifouling property, a silica−PVP nanocomposite was synthesized and used as a novel hydrophilic additive to modify polyethersulfone (PES) membranes. Transmission electron microscopy (TEM) observation showed that PES membranes, using additives of PVP and silica−PVP nanocomposites, have similar asymmetric structures. X-ray photoelectron spectroscopy (XPS) measurement indicated that the near-surface coverage of PVP for PES membrane with a silica−PVP nanocomposite additive is greater than that with a PVP additive. Protein ultrafiltration experiment also showed that the antifouling ability of PES membrane with a silica-PVP nanocomposite additive is stronger than that with a PVP additive. The hydrophilic modification with a silica−PVP nanocomposite is an appropriate method for improved antifouling property of PES ultrafiltration membranes.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900560e

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 780–789

Titre :	Isoelectric separation of proteins using charged ultrafilter membranes with different functionality under coupled driving forces
Type de document :	texte imprimé
Auteurs :	Saxena, Arunima, Auteur ; Shahi, Vinod K., Auteur
Année de publication :	2010
Article en page(s) :	pp 780–789
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Membrane process Isoelectric separation proteins.
Résumé :	A simple membrane process for the protein fractionation under coupled driving forces (pressure and potential difference) has been developed using acidic functionalized (sulphonated, carboxyleted, and phosphorylated) ultrafilter membranes, based on the interpolymer of poly(vinyl chloride) (PVC) and styrene-divinyl benzene (DVB) copolymer. Introduction of the different functional groups was confirmed by Fourier transform infrared (FTIR), CHNS analysis, and ion-exchange capacity measurements. Molecular weight cut off (MWCO) determination of these membranes suggested their ultrafilter nature, while their contact angle values showed hydrophilic characteristics. The apparent pore radius of these membranes was estimated by water permeation studies, while electro-osmotic permeation data was used for the determination of zeta potential under the operating environment. Systematic studies on the effects of pH, or nature of the charge on the casein (CAS) and lysozyme (LYS), on their adsorption characteristic using these charged ultrafilter membranes were carried out. Protein transmission (selectivity) and membrane throughput across both membranes were studied using binary mixture of protein under different gradients at pH points: 2.0, 5.0, 10.7, and 13.0. It was concluded that separation from the binary mixture of CAS−LYS of LYS at pH 5.0 (pI of CAS) using charged ultrafilter membranes was possible with high selectivity and throughput. It was observed that transmission of protein can be governed by varying the nature and extent of charge on the protein (pH) and membrane matrix, polarity of applied potential gradient with an ultrafilter membrane of given pore dimensions. In these novel processes, charge on the protein, nature and extent of the charge on the membrane interfaces, and polarity of the potential gradient all are governing the transport of a given protein across the membrane, which resulted high selectivity and membrane throughput under coupled driving forces.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900258d

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 772–779

Titre :	Rigorous modeling and simulation of an absorption−stripping loop for the removal of acid gases
Type de document :	texte imprimé
Auteurs :	Huepen, Bernhard, Auteur ; Kenig, Eugeny Y., Auteur
Année de publication :	2010
Article en page(s) :	pp 772–779
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Acid gases Absorption Stripping.
Résumé :	In this work, a universal rate-based model is presented that enables the rigorous simulation of absorption and stripping units, as well as their combination as an absorption−stripping loop. The latter is realized by simultaneous treatment of the two units and their environment. The model is applied to the removal of acid gases by aqueous amine solutions. It is capable of describing the complex interplay of chemical reactions and heat and multicomponent mass transfer, as well as accounting for thermodynamic nonidealities including the specific behavior of electrolyte solutions. Furthermore, the influence of column internals and hydraulics is considered through relevant correlations. To simulate the total absorption−stripping loop, the model is supplemented by additional submodels for the column periphery (e.g., heat exchangers). All models are implemented in the simulation environment Aspen Custom Modeler and validated by comparison with experimental data of an industrial-scale acid gas removal process. In addition, the effects of model parameters on the behavior of both the absorption and stripping columns and the impact of model simplifications are investigated.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9003927

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 761–771

Titre :	Multivariable process control : decentralized, decoupling, or sparse?
Type de document :	texte imprimé
Auteurs :	Shen, Yuling, Auteur ; Wen-Jian Cai, Auteur ; Shaoyuan Li, Auteur
Année de publication :	2010
Article en page(s) :	pp 761–771
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Multivariable control PID Industrial processes Decoupling.
Résumé :	In this article, a systematic approach is proposed to design PI-/PID-based multivariable control systems in which the designs and analyses of decentralized, decoupling, and sparse control schemes are all treated under a unified framework. First, based on the relative normalized gain array (RNGA), a best loop pairing is obtained using the RGA (relative gain array)−Nederlinski index (NI)−RNGA rules. The index matrix is then calculated, and the control structure is determined according to a selection criterion. Finally, the selected loop controllers are independently designed based on equivalent transfer functions. The effectiveness of the proposed design approach is verified by analysis of several multivariable industrial processes, demonstrating that the selected control structure results in better overall system performance.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901453z#afn1

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 750–760

Titre :	Plantwide design of transesterification reactive distillation to co-generate ethyl acetate and n-butanol
Type de document :	texte imprimé
Auteurs :	Wang, San-Jang, Auteur ; Huang, Hsiao-Ping, Auteur ; Yu, Cheng-Ching, Auteur
Année de publication :	2010
Article en page(s) :	pp 750–760
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Reactive distillation RD Ethyl Acetat N-Butanol.
Résumé :	Reactive distillation (RD) in the face of azeotrope(s) in the separation of a mixture from an RD column might need debottlenecking design and more columns to obtain high-purity products. Under such circumstances, the integration of heat with the process becomes an effective consideration for reducing costs. In this study, an RD process to produce ethyl acetate and n-butanol from ethanol and n-butyl acetate by conducting a transesterification reaction is presented. The products from the RD column include n-butanol and an ethanol/ethyl acetate mixture. Designs with alternative configurations are used to illustrate plantwide designs of the process with heat integration/coupling. Among these alternatives are two with three columns and one with two columns. In the three-column configurations, separation of ethanol/ethyl-acetate mixtures from the top product of the RD column is conducted by extractive distillation or pressure-swing distillation. The other configuration consists of an RD column followed by a conventional distillation column operated at high pressure. Systematic design procedures are used to optimize the flowsheets of different configurations by minimizing the total annual cost. Heat integration and thermal coupling technologies are used in these three configurations to attempt to provide more economical designs. The results show that the selection of separation system depends on whether heat integration/coupling is considered. In this case, the two-column reactive distillation process with heat integration yields high-purity products and the lowest total annual cost.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901413c

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 735–749

Titre :	Design and control of dimethyl carbonate−methanol separation via extractive distillation in the dimethyl carbonate reactive-distillation process
Type de document :	texte imprimé
Auteurs :	Hsu, Kai-Yi, Auteur ; Hsiao, Yuan-Chang, Auteur ; Chien, I-Lung, Auteur
Année de publication :	2010
Article en page(s) :	pp 735–749
Note générale :	Génie chimique
Langues :	Anglais (eng)
Mots-clés :	Dimethyl carbonate Methanol Ethylene Reactive distillation.
Résumé :	Dimethyl carbonate is an environmentally benign and biodegradable chemical. It can be produced by a transesterification reaction of methanol with ethylene carbonate, coproducing another useful product, ethylene glycol. A reactive distillation column can be utilized for the complete conversion of ethylene carbonate with methanol in excess. The coproduct, ethylene glycol, is the bottom product while the top product of this reactive distillation column is a mixture of dimethyl carbonate and methanol close to the azeotropic composition. In this paper, an economical separation process via extractive distillation is proposed to obtain pure dimethyl carbonate product and also pure methanol to be recycled to the reactive distillation column. A very simple procedure is proposed in this paper for the quick comparison of alternative entrainer candidates before rigorous process simulation is conducted. Aniline is found to be a very effective entrainer to enhance the relative volatility between methanol and dimethyl carbonate. A problem with small heavy-boiler impurities in the feed stream of the extractive distillation process is also pointed out, with a practical solution given for this problem. Simple overall control strategy of this process is also proposed to maintain product purity despite various feed disturbances. Only one tray temperature control loop is required for each of the columns.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901157g

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 719–734

Titre :	Design and control of the cumene process
Type de document :	texte imprimé
Auteurs :	William L. Luyben, Auteur
Année de publication :	2010
Article en page(s) :	pp 719–734
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Cumene Chemical processes Benzene Propylene.
Résumé :	The chemistry of the cumene process features the desired reaction of benzene with propylene to form cumene and the undesirable reaction of cumene with propylene to form p-diisopropylbenzene. Both reactions are irreversible. Since the second has a higher activation energy than the first, low reactor temperatures improve selectivity of cumene. However, low reactor temperatures result in low conversion of propylene for a given reactor size or require a large reactor for a given conversion. In addition, selectivity can be improved by using an excess of benzene to keep cumene and propylene concentrations low, but this increases separation costs. Therefore, the process provides an interesting example of plantwide economic design optimization in which there are many classical engineering trade-offs: reactor size versus temperature, selectivity versus recycle flow rate, and reactor size versus recycle flow rate. Design optimization variables affect both energy costs and capital investment. They also affect the amount of reactants required to produce a specified amount of cumene product. The economic effect of reactant consumption is very large, an order of magnitude greater than the impact of energy or capital. The process is presented in the design book by Turton et al. (Analysis, Synthesis and Design of Chemical Processes, 2nd ed.; Prentice Hall: Saddle River, NJ, 2003) and consists of a cooled tubular reactor and two distillation columns. The liquid fresh feeds and the benzene recycle stream are vaporized, preheated, and fed into the vapor-phase reactor, which is cooled by generating steam. Reactor effluent is cooled and fed to the first column that produces a distillate stream of benzene that is recycled back to the reactor. The second column separates the desired cumene product from the undesired p-diisopropylbenzene. The purpose of this paper is to develop the economically optimum design considering capital costs, energy costs, and raw material costs and then to develop a plantwide control structure capable of effectively handling large disturbances in production rate.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9011535

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 701–718

Titre :	Optimal production scheduling and lot-sizing in dairy plants : the yogurt production line
Type de document :	texte imprimé
Auteurs :	Kopanos, Georgios M., Auteur ; Puigjaner, Luis, Auteur ; Georgiadis, Michael C., Auteur
Année de publication :	2010
Article en page(s) :	pp 701–718
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Yogurt production Pasteurization Homogenization.
Résumé :	The lot-sizing and production scheduling problem in a multiproduct yogurt production line of a real-life dairy plant is addressed in this work. A new mixed discrete/continuous-time mixed-integer linear programming model, based on the definition of families of products, is proposed. The problem under question is mainly focused on the packaging stage, whereas timing and capacity constraints are imposed with respect to the pasteurization/homogenization and fermentation stage. Packaging units operate in parallel and share common resources. Sequence-dependent times and costs are explicitly taken into account and optimized by the proposed framework. Several scenarios for a large-scale dairy plant have been solved to optimality using the proposed model. Production bottlenecks are revealed, and several retrofit design options are proposed to enhance the production capacity and flexibility of the plant.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901013k

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 690–700

Titre :	Simple analytical min−max model matching approach to robust proportional-integrative-derivative tuning with smooth set-point response
Type de document :	texte imprimé
Auteurs :	S. Alcantara, Auteur ; C. Pedret, Auteur ; Vilanova, R., Auteur
Année de publication :	2010
Article en page(s) :	pp 690–700
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	PID controller Simple analytical Integrative Derivative.
Résumé :	This communication addresses the set-point robust proportional-integrative-derivative (PID) tuning for stable first order plus time delay systems from a general min−max model matching formulation. As opposed to some recent optimization-based numerical procedures, the derivation is carried out analytically, and it is based on a Smith-type inverse response configuration. Within the considered context, several choices result in a standard PID. This work investigates the simplest one, leading to a PID controller solely depending on a single design parameter. This contrasts with other analytical approaches resulting in more involved tuning. Attending to common performance/robustness indicators, the free parameter is finally fixed to provide an automatic tuning solely dependent on the model information. Toward this transition, dimensional analysis proves fruitful and allows us to establish that the proposed tuning rule is very robust for lead-dominant plants in the presence of parametric uncertainty. Lastly, simulation examples show that the suggested compensator yields very good results.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9010194

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 682–689

Titre :	Conceptual evaluation of integrated process configurations for the recovery of i-phenylalanine product crystals during fermentation
Type de document :	texte imprimé
Auteurs :	Cuellar, Maria C., Auteur ; Straathof, Adrie J. J., Auteur ; Van de Sandt, Emile J. A. X., Auteur
Année de publication :	2010
Article en page(s) :	pp 682–689
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Amino acid Anhydrate crystals.
Résumé :	The production of the amino acid l-phenylalanine (Phe) by fermentation is in many cases limited by the tight regulation of the microbial pathway leading to Phe synthesis. One way of circumventing feedback repression is to remove the product from the vicinity of the micro-organism as soon as it is being formed. In the case of Phe, techniques like adsorption and extraction have been applied with this aim. In these processes, however, additional recovery steps are required in order to obtain the product as anhydrate crystals, which is its commercial form. In this work we evaluated conceptually the recovery of Phe anhydrate crystals during a fermentation process. The product recovery consisted of water removal by reverse osmosis, crystallization, and recycle of the mother liquor either to the fermenter, to the water removal unit or to both. By maintaining the Phe mass fraction in the fermenter at about 17 g kg−1 the fermentation productivity increased according to the calculations from 0.66 g kg−1 h−1, without product removal, to 1.07 g kg−1 h−1, with product removal, where about 70% of the produced Phe was directly recovered as anhydrate crystals. By means of a simplified economic model it was shown that the membranes required for cell retention and water removal have much more impact on the economic performance of the process than the consumption of raw materials, and therefore, the favored recycling option for the mother liquor is to the water removal unit
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901007g

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 669–681

Titre :	Phase-based joint modeling and spectroscopy analysis for batch processes monitoring
Type de document :	texte imprimé
Auteurs :	Zhao, Chunhui, Auteur ; Gao, Furong, Auteur ; Wang, Fuli, Auteur
Année de publication :	2010
Article en page(s) :	pp 669–681
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Spectroscopy Processes monitoring Chemical reactions.
Résumé :	Spectroscopy is a useful tool for analyzing chemical information in batch processes. However, conventional spectroscopic techniques can lead to complex model structures and difficult-to-interpret results because of the direct use of redundant wavelength variables. To solve this problem, the ICA technique has been used first to reveal the underlying independent sources from the observed mixtures and their mixing coefficients. This analysis associates the constituent species with their respective effects on the mixture spectra, which could make more sense for spectroscopy. In the following article, the use of mixing coefficients instead of redundant wavelength variables can provide a convenient modeling platform from which the phase-specific characteristics of chemical reactions are readily identified. Consequently, a phase-based joint modeling framework is formulated for process monitoring by combining different latent-variable- (LV-) based algorithms. It decomposes different types of systematic variations in spectral measurements (X) and then sets up different monitoring systems for them. Monitoring different parts of X can provide abundant process information about the status of the operation from a comprehensive viewpoint, thus benefitting process understanding and fault detection. The effectiveness of this approach is demonstrated by application to two case studies.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9005996

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 658–668

Titre :	Detection of safe operating regions : anovel dynamic process simulator based predictive alarm management approach
Type de document :	texte imprimé
Auteurs :	Varga, Tams, Auteur ; Szeifert, Ferenc, Auteur ; Abonyi, Janos, Auteur
Année de publication :	2010
Article en page(s) :	pp 658–668
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Dynamic process Simulator Alarm management.
Résumé :	The operation of complex production processes is one of the most important research and development problems in process engineering. A safety instrumented system (SIS) performs specified functions to achieve or maintain a safe state of the process when unacceptable or dangerous process conditions are detected. A logic solver is required to receive the sensor input signal(s), to make appropriate decisions based on the nature of the signal(s), and to change its outputs according to user-defined logic. The change of the logic solver output(s) results in the final element(s) taking action on the process (e.g., closing a valve) to bring it back to a safe state. Alarm management is a powerful tool to support the operators’ work to control the process in safe operating regions and to detect process malfunctions. Predictive alarm management (PAM) systems should be able not only to detect a dangerous situation early enough, but also to give advice to process operators which safety action (or safety element(s)) must be applied. The aim of this paper is to develop a novel methodology to support the operators how to make necessary adjustments in operating variables at the proper time. The essential of the proposed methodology is the simulation of the effect of safety elements over a prediction horizon. Since different manipulations have different time demand to avoid the evolution of the unsafe situation (safety time), the process operators should know which safety action(s) should be taken at a given time. For this purpose a method for model based predictive stability analysis has been worked out based on
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9005222

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 648–657

Titre :	New approach to develop dynamic gray box model for a plasticating twin-screw extruder
Type de document :	texte imprimé
Auteurs :	Iqbal, Mohammad H., Auteur ; Sundararaj, Uttandaraman, Auteur ; Shah, Sirish L., Auteur
Année de publication :	2010
Article en page(s) :	pp 648–657
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Dynamic Plasticating TSE High-density polyethylenes.
Résumé :	The dynamic behaviors of the process variables of a twin screw extruder (TSE) have inherent nonlinearity and time delay. Thus, it is important to develop a process model and furthermore to design controllers based on that model for stable operation. A new approach is explained in this work to develop dynamic gray box models to predict the responses of the process output variables due to change in the screw speed (N) for a plasticating TSE. This approach comprises the selection of controlled variables and the development of gray box models relating the selected controlled variables and N. The selection of variables was based on both the steady-state correlation analysis with final product properties and the dynamic considerations. High-density polyethylenes with different melt indices were extruded in a co-rotating TSE in this work. A predesigned random binary sequence type excitation in N was imposed for the dynamic study. Gray box models were developed between two output variables, melt temperature (Tmelt) at die and melt pressure (Pmelt) at die, with N, by incorporating both first principles knowledge of the process and the measured process data using the classical system identification technique. A second-order ARMAX (autoregressive moving average with exogenous input) model was found to be sufficient to capture the dynamic behaviors of Tmelt when N was changed. However, the dynamic behavior of Pmelt was modeled by a third-order ARMAX structure. Both models are in agreement with the a priori process information of the TSE.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900190z

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 633–647

Titre :	An analysis of some unit-specific event-based models for the short-term scheduling of noncontinuous processes
Type de document :	texte imprimé
Auteurs :	Jie Li, Auteur ; Susarla, Naresh, Auteur ; Iftekhar A. Karimi, Auteur
Année de publication :	2010
Article en page(s) :	pp 633–647
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Noncontinuous processes Semicontinuous processes Finite storage Unit-specific.
Résumé :	Several event-based formulations for scheduling noncontinuous processes have been reported in the past decade. In fact, some unit-specific event-based models have proved more efficient than other models on several literature problems. Recently, Janak and Floudas [Comput. Chem. Eng. 2008, 32 (4−5), 913−955] and Shaik and Floudas [Ind. Eng. Chem. Res. 2009, 48 (6), 2947−2964] have shown that, without allowing tasks to occur over multiple events, some unit-specific event-based models may lead to suboptimal solutions. In this work, we present five examples, involving batch and semicontinuous processes, to study the performance of some recent variants of unit-specific event-based models. The first two examples involve batch plants with finite storage as a shared resource for which a recent unit-specific event-based model [Shaik, M. A.; Floudas, C. A. Comput. Chem. Eng. 2008, 32 (1−2), 260−274] gives trivial or suboptimal solutions, depending on the example and data. Our analysis confirms that assuming a single event point for each task is one cause for the observed performance. When the tasks are allowed to span multiple events using the recent unified model of Shaik and Floudas [Ind. Eng. Chem. Res. 2009, 48 (6), 2947−2964], the issue is resolved. Three more examples involving semicontinuous processes are considered, the solutions of which explore the limitations of a recent unit-specific event-based model [Shaik, M. A.; Floudas, C. A. Ind. Eng. Chem. Res. 2007, 46 (6), 1764−1779]. In addition, the task sequencing constraints in the later model may require further study to ensure generality. The five examples presented in this work can serve as test problems for future scheduling models.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801879n

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 623–632

Titre :	Turbulent liquid−liquid dispersion in sulzer SMX mixer
Type de document :	texte imprimé
Auteurs :	Theron, Félicie, Auteur ; Le Sauze, Nathalie, Auteur ; Ricard, Alain, Auteur
Année de publication :	2010
Article en page(s) :	pp 623–632
Note générale :	Génie chimique
Langues :	Anglais (eng)
Mots-clés :	Turbulent Sulzer SMX Turbulent flow Kolmogorov’s theory.
Résumé :	This paper presents an experimental study of pressure drop of single-phase flow and liquid−liquid dispersion through a Sulzer SMX mixer in the turbulent flow regime. Emulsification experiments are performed with various numbers of mixing elements from 2 to 20 and different flow rates ranging from 204 to 600 L/h. Pressure drop in single phase flow when Re is greater than 800 is modeled using a correlation based on the Blasius approach. The pressure drop is quantified at high Reynolds numbers for a liquid−liquid system. The droplet size distribution evolves along the mixer, and 10 mixing elements are required to reach break-up coalescence equilibrium in the case of emulsification experiments. Finally, assuming Kolmogorov’s theory of isotropic turbulence, a new correlation is established to predict the Sauter mean diameter in this mixing device as a function of the Reynolds and Weber numbers as well as the number of mixing elements.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900090d

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 613–622

Titre :	In situ monitoring of cement gel growth dynamics. use of a miniaturized permanent halbach magnet for precise 1H NMR studies
Type de document :	texte imprimé
Auteurs :	Karakosta, Eleni, Auteur ; Diamantopoulos, George, Auteur ; Katsiotis, Marios S., Auteur
Année de publication :	2010
Article en page(s) :	pp 613–622
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Permanent magnet Cement Chemical composition.
Résumé :	The most critical parameter that affects important cement paste properties, such as strength, shrinkage, creep, and permeability, is its pore structure. Pores in hydrated cement form an extremely complicated network, with a very broad size distribution, ranging from nanometers to millimeters, which changes with the chemical composition, relative humidity, temperature, and applied load. Here, without recourse to drying methods, we monitor the evolution of the pore structure during the progressive hydration and setting of three white cement pastes with different hydration kinetics. By combining 1H nuclear magnetic resonance (NMR) spin−lattice relaxation T1 and diffusion measurements, performed in a portable 0.29 T Halbach magnet, it is possible to distinguish between gel and capillary pores and to study the growth dynamics of cement gel (T1 measurements) and the associated shrinkage of the capillary pore system (diffusion measurements). In this way, aspects of the hydration kinetics are unveiled, which are difficult to observe with other techniques.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901178q

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 609–612

Titre :	Polymeric networks assembled by adamantyl and β-cyclodextrin substituted poly(acrylate)s : host−guest interactions, and the effects of ionic strength and extent of substitution
Type de document :	texte imprimé
Auteurs :	Wang, Jie, Auteur ; Pham, Duc-Truc, Auteur ; Xuhong Guo, Auteur
Année de publication :	2010
Article en page(s) :	pp 609–612
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Polymer networks Cyclodextrine Acrylate Ionic strength.
Résumé :	The construction of polymer networks through host−guest complexation between the β-cyclodextrin (βCD) substituents of 6A-(1-(2-aminoethyl)amino)-6A-deoxy-β-cyclodextrin 2, 3, and 6% randomly substituted poly(acrylate) (PAAβCDen) and the adamantyl (AD) substituents of 1-(2-aminoethyl)amidoadamantyl 2, 3, and 6% randomly substituted poly(acrylate) (PAAADen) is reported. A 2D 1H NOESY NMR spectroscopic study shows the formation of host−guest complexes by the βCD and AD substituents. This is characterized by a complexation constant, K1 = 3020 ± 60 mol−1 dm3, for 3% substituted PAAβCDen and PAAADen as shown by isothermal titration calorimetry. The viscosity of a 2 wt % equimolar mixture of 3% randomly substituted PAAβCDen and PAAADen reaches a maximum at [NaCl] = 0.1 mol dm−3, and the viscosity and the storage and loss moduli (G′ and G′′) increase with the increase in degree of substitution from 2 to 6%.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901178q

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 602–608

Titre :	Synthesis of uniform porous silica microspheres with hydrophilic polymer as stabilizing agent
Type de document :	texte imprimé
Auteurs :	Ahmed, Adham, Auteur ; Clowe, Rob, Auteur ; Willneff, Elizabeth, Auteur
Année de publication :	2010
Article en page(s) :	pp 602–608
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Silica Microspheres Hydrophilic Polymer.
Résumé :	Porous silica microspheres have wide applications in various areas. It has been a challenge to produce uniform silica microspheres with tunable pore size. In this study, uniform porous silica microspheres were synthesized using a modified Stber method. Cetyltrimethylammonium bromide (CTAB) was used as a cationic surfactant to introduce ordered mesoporosity into silica spheres. Hydrophilic polymers poly(vinyl alcohol) (PVA), polyvinylpyrrolidone (PVP), and poly(ethylene glycol) (PEG) were introduced into the reaction system. It was found that the use of PVA led to the formation of uniform and well-dispersed porous silica microspheres. The effect of the polymers on pore size and particles morphology was also studied. Another cationic surfactant dihexadecyldimethylammonium bromide (DiCTAB) and a nonionic surfactant (Brij-35) were further investigated by replacing CTAB. Uniform nonporous silica nanospheres were formed for Brij-35 and Brij-35/PVA systems. The use of DiCTAB resulted in submicrometer silica spheres with high surface area and larger pore size. The addition of PVA into the reaction system dramatically reduced the surface area and pore volume. The mesopores in the silica microspheres formed from the CTAB-PVA template were expanded using 1,3,5-trimethylbenzene and N,N-dimethyldecylamine as swelling agents by a hydrothermal method. The pore size was increased from 2.7 to 4.5 nm and 6.5 nm, respectively.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901213v

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 592–601

Titre :	Measurement and prediction of interfacial tension of binary mixtures
Type de document :	texte imprimé
Auteurs :	Nino-Amezquita, Oscar G., Auteur ; Enders, Sabine, Auteur ; Jaeger, Philip T., Auteur
Année de publication :	2010
Article en page(s) :	pp 592–601
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Binary mixtures Peng−Robinson equation Methane Hexane Liquid composition.
Résumé :	The density gradient theory was combined with a modern equation of state based on statistical mechanics, the perturbed chain-statistical association fluid theory, or with the well-known Peng−Robinson equation of state, and is applied to compute the surface tension of various binary mixtures made up of nonpolar substances. Additionally, some new data for the system methane + hexane and methane + heptane were measured using the pendant drop method equipped with a high-pressure cell. Both equations of state can be used to predict the surface tension of mixtures very close to experimental data. The surface tension of pure ethane could also be predicted using the surface tension data of other n-alkanes. Additionally, the surface tensions for mixtures as a function of liquid composition, of temperature, and of pressure were calculated for systems, where no experimental data are available. If the mixture contains a high volatile component, strong relative enrichment effects in the interface could be observed.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901209z

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 583–591

Titre :	Novel one-step synthesis route to ordered mesoporous silica-pillared clay using cationic−anionic mixed-gallery templates
Type de document :	texte imprimé
Auteurs :	Mao, Huihui, Auteur ; Li, Baoshan, Auteur ; Li, Xiao, Auteur
Année de publication :	2010
Article en page(s) :	pp 583–591
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Silica-Pillared Micromesoporous X-ray diffraction.
Résumé :	A novel one-step synthesis route to ordered mesoporous silica-pillared clay (SPC) with cantonic−anionic mixed-gallery templates has been successfully established. This approach involves the type and formation of surfactant mixture for SPC through intragallery ammonia-catalyzed tetraethoxysilane (TEOS). The formation of a precursor with a micromesoporous framework is a result of TEOS hydrolysis and the presence of surfactant micelles in the gallery regions under ammonia-catalyzed conditions. The type of structure was confirmed by X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and low-temperature N2 physisorption. Addition of the anionic surfactant resulted in changes of the layered structure and ratio of micropores to mesopores. The formation mechanism of SPC derivatives is proposed.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9011563

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 578–582

Titre :	Highly photoluminescent and stable aqueous ZnS quantum dots
Type de document :	texte imprimé
Auteurs :	Li, Hui, Auteur ; Shih, Wan Y., Auteur ; Shih, Wei-Heng, Auteur
Année de publication :	2010
Article en page(s) :	pp 578–582
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Aqueous photoluminescent ZnS quantum Mercaptopropionic acid.
Résumé :	We report an all-aqueous synthesis of highly photoluminescent and stable ZnS quantum dots (QDs) with water as the medium. The method involves first synthesizing ZnS QDs with 3-mercaptopropionic acid (MPA) as the capping molecule and then replacing some of the MPA with (3-mercaptopropyl)trimethoxysilane (MPS). The resultant MPS-replaced ZnS QDs were about 5 nm in size with a cubic zinc blende crystalline structure, and they had both MPA and MPS on the surface as confirmed by Fourier transform infrared (FTIR) spectroscopy. They exhibited blue trap-state emissions around 415 nm and a quantum yield (QY) of 75% with rhodamine 101 as the reference, and they remained stable for more than 60 days under ambient conditions. Through the capping-molecule replacement procedure, the MPS-replaced ZnS QDs avoided the shortcomings of both MPA/ZnS QDs and MPS/ZnS QDs and acquired the advantages of strong photoluminescence and good stability, which are important to QD applications, especially for bioimaging.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901086d

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 572–577

Titre :	Reinforcing and toughening effects of bamboo pulp fiber on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) fiber composites
Type de document :	texte imprimé
Auteurs :	Jiang, Long, Auteur ; Feng Chen, Auteur ; Qian, Jun, Auteur
Année de publication :	2010
Article en page(s) :	pp 572–577
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Fiber Composites Hydroxybutyrate Hydroxyvalerate.
Résumé :	In this work, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/bamboo pulp fiber composites were melt-compounded and injection-molded. Tensile, impact and dynamic mechanical properties of the composites were studied. In contrast to many other short natural fiber reinforced biocomposites which demonstrate decreased strain-at-break, impact toughness and tensile strength, the PHBV/bamboo pulp fiber composites displayed increased tensile strength and impact toughness, and maintained/increased strain-at-break. Microscopic study of the fracture surfaces revealed extensive fiber pullout in both tensile and impact tests. The fiber pullout suggests insufficient interfacial adhesion between the fiber and the matrix. The pullout process in the impact testing dissipated a significant amount of energy and hence substantially improved the impact toughness of the composites. With the improved interfacial adhesion provided by coupling agent polymeric diphenylmethane diisocyanate (pMDI), the strength and modulus of the composites were further increased. However, the toughness was decreased due to the inhibition of the fiber pullout. An acoustic emission test revealed a significantly different process of structural change for the composites with/without pMDI during tension test.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900953z

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 559–571

Titre :	Molecular simulation of the thermal and transport properties of three alkali nitrate salts
Type de document :	texte imprimé
Auteurs :	Jayaraman, Saivenkataraman, Auteur ; Thompson, Aidan P., Auteur ; Anatole von Lilienfeld, O., Auteur
Année de publication :	2010
Article en page(s) :	pp 559–571
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Thermodynamic Molecular simulation Nitrate
Résumé :	Thermodynamic and transport properties for nitrate salts containing lithium, sodium, and potassium cations were computed from molecular simulations. Densities for the liquid and crystal phases calculated from simulations were within 4% of the experimental values. A nonequilibrium molecular dynamics method was used to compute viscosities and thermal conductivities. The results for the three salts were comparable to the experimental values for both viscosity and thermal conductivity. Computed heat capacities were also in reasonable agreement with experimental values. The computed melting point for NaNO3 was within 15 K of its experimental value, while for LiNO3 and KNO3, computed melting points were within 100 K of the experimental values. The results show that very small free-energy differences between the crystal and liquid phases can result in large differences in computed melting point. To estimate melting points with an accuracy of around 10 K, simulation methods and force fields must yield free energies with an accuracy of around 0.25 kcal/mol. Tests conducted on a well-studied sodium chloride model indicated negligible dependence of the computed melting point on system size or choice of integration temperature.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9007216

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 548–558

Titre :	Modeling and multiresolution characterization for microfabrication applications
Type de document :	texte imprimé
Auteurs :	Mukherjee, Rajib, Auteur ; Hung, Francisco R., Auteur ; Palazoglu, Ahmet, Auteur
Année de publication :	2010
Article en page(s) :	pp 548–558
Note générale :	Génie chimique
Langues :	Anglais (eng)
Mots-clés :	Microélectroniques Microelectromechanical Photoresist polymer Phase separation.
Résumé :	In the fabrication of microelectronic and microelectromechanical systems (MEMS) devices, geometric patterns are transferred onto the substrate by the process of lithography. A photoresist polymer is used in the process, which affects the surface morphology, causing line-edge roughness (LER) and surface roughness (SR) in the transferred patterns. The performance of the resulting device is critically influenced by the LER and SR of the surface. Various microscopy image analysis techniques are commonly used for LER and SR characterization, using metrics such as σ, correlation length, and fractal dimension (FD). In this work, a mesoscale lattice Monte Carlo (MC) simulation is performed to model the photoresist system. Phase separation by spinodal decomposition is found as the cause of roughness. Multiresolution LER and SR characterization is performed on the model structure. The results complement the multiresolution LER characterization from image analysis and provide additional insight toward SR characterization, which is not feasible using two-dimensional SEM images.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900568g

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 541–547

Titre :	Pigmentation of boc-indanthrone in organic solvent/photopolymer through a thermal process
Type de document :	texte imprimé
Auteurs :	Liu, Tang-Hao, Auteur ; Wen-Tung Cheng, Auteur ; Huang, Kuo-Tung, Auteur
Année de publication :	2010
Article en page(s) :	pp 541–547
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Organic solvent photopolymer Thermogravimetric.
Résumé :	This work explores a pigment converted from a latent pigment in organic solvent and photopolymer through a thermal process. Measurements by thermogravimetric analysis (TGA), ultraviolet−visible (UV−vis) spectroscopy, and Fourier transform infrared (FTIR) spectroscopy showed that regeneration of the pigment from boc-indanthrone in the solvent or photopolymer could be achieved by heating. X-ray diffraction (XRD) was employed to characterize the regenerated pigments. As shown in the results, the recrystallized structure is similar to the structure of the parent pigment. Analysis using field-emission scanning electron microscopy (FESEM) indicated that the particles of the re-formed pigment in the solvent were initially cubic, then aggregated into loose bars, and finally became firmly slated and flat for hydrogen-bonding and π−π stacking interactions. In addition, the morphology of the reproduced pigment was found to be cubic, as in the photopolymer.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900078h

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 535-540

Titre :	Hydration of 1-phenyl-1-propyne in high-temperature water with catalysis by water-tolerant lewis acids
Type de document :	texte imprimé
Auteurs :	Rebacz, Natalie A., Auteur ; Phillip E. Savage, Auteur
Année de publication :	2010
Article en page(s) :	pp 535-540
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Hydration phenyl propyne Water tolerant Lewis acids.
Résumé :	We explore various aspects of alkyne hydration in high temperature water catalyzed by water-tolerant Lewis acids through experimentation with the hydration of 1-phenyl-1-propyne. Experiments comparing indium triflate, scandium triflate, ytterbium triflate, sulfuric acid, and hydrochloric acid indicate that indium triflate is the most active catalyst toward this reactive system of those tested. Experiments with quartz and stainless steel reactors in conjunction with quartz and stainless steel additive demonstrate that reactor material of construction has no appreciable effect upon the reaction. The reaction is first order in both catalyst and alkyne. We further determine the kinetic parameter k for four temperatures (150, 175, 200, and 225 °C), and find that the frequency factor is 108.8±0.3 L/(mol s) and the activation energy is 21.4 ± 0.6 kcal/mol for this transformation. This is the first example of alkyne hydration in high-temperature water catalyzed by water-tolerant Lewis acids.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9017513

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 526–534

Titre :	Production of synthesis gas from methane using lattice oxygen of NiO−Cr2O3−MgO complex oxide
Type de document :	texte imprimé
Auteurs :	Nakayama, O., Auteur ; Ikenaga, N., Auteur ; Miyake, T., Auteur
Année de publication :	2010
Article en page(s) :	pp 526–534
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Gas Methane Lattice oxygen NiO−Cr2O3−MgO Complex Oxide.
Résumé :	To produce nitrogen-free synthesis gas or hydrogen by the partial oxidation of methane using air as an oxidant, NiO−Cr2O3−MgO complex oxide was proposed as an effective one. Lattice oxygen of NiO in the complex oxide was effectively transferred to CH4 to give H2 and CO in the ratio of 2−3:1 at 700 °C. NiO was reduced to metallic Ni during the course of the reaction with CH4, and the reduced Ni was successfully oxidized to NiO with air at 700 °C. Repeated cycles of the reaction and oxidation were carried out without any loss of activity. The role of Cr2O3 seemed to weaken the Ni−O bond in NiO−MgO complex oxide, in which NiO is less reducible with CH4 at 700 °C. In addition, the surface oxidation state of Ni was increased to Ni3+ with Cr2O3.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9013474

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 520–525

Titre :	Demonstration of a process for the conversion of kraft lignin into vanillin and methyl vanillate by acidic oxidation in aqueous methanol
Type de document :	texte imprimé
Auteurs :	Voitl, Tobias, Auteur ; von Rohr, Philipp Rudolf, Auteur
Année de publication :	2010
Article en page(s) :	pp 520–525
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Conversion Kraft Oxidation Aqueous methanol.
Résumé :	In this work, a process for producing vanillin and methyl vanillate from an industrial kraft lignin by oxidation in aqueous methanol at acidic pH is proposed. A series of consecutive runs, comprising the steps of kraft lignin oxidation, monomer extraction, and filtration of residual lignin, were conducted. The depolymerization of kraft lignin (1 g per run) was carried out in a stirred batch reactor with 80 vol % methanol/water as the solvent, with H3PMo12O40 as a homogeneous catalyst, and with 10 bar of oxygen initially present. The monomeric products were recovered from the process by extraction with chloroform and quantified by gas chromatography/mass spectrometry (GC/MS). Residual kraft lignin was recovered from the reaction medium by filtration. After extraction and filtration, the reaction medium, containing the homogeneous catalyst, was reused in the next run. The sum of all quantified products (gas phase, extract, and solids), as well as the amount of consumed oxygen, reached constant levels after five runs, and no indications of catalyst deactivation were found. Extracted products containing vanillin (3.5 wt %) and methyl vanillate (3.5 wt %) were recovered with a yield of 65 wt %. The extracted products were further analyzed by size exclusion chromatography (SEC) and Fourier transform infrared (FTIR) spectroscopy regarding their average molecular weight and functional group contents.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901293p

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 515–519

Titre :	Reactivities of NaOH enhanced iron blast furnace slag/hydrated lime sorbents toward SO2 at low temperatures : effects of the Presence of CO2, O2, and NOx
Type de document :	texte imprimé
Auteurs :	Liu, Chiung-Fang, Auteur ; Shih, Shin-Min, Auteur ; Yang, Jung-Hsin, Auteur
Année de publication :	2010
Article en page(s) :	pp 515–519
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Reactivities NaOH Hydrated lime sorbents.
Résumé :	The effects of the addition of NaOH on the reactivities toward SO2 of iron blast furnace slag/hydrated lime (BFS/HL) sorbents were studied without and with the presence of flue gas components, CO2, O2, and NOx, under the conditions prevailing in the bag filters of dry and semidry flue gas desulfurization processes. The reactivities of sorbents were markedly enhanced by the addition of NaOH when CO2, O2, and NOx were not present in the gas mixture. The enhancement effect mainly resulted from the deliquescent property of NaOH. With the presence of CO2, O2, and NOx at their typical concentrations in the flue gas, the sorbent reactivity was greatly increased due to the oxidation of bisulfite and sulfite ions to sulfate ions as well as the formation of deliquescent salts, calcium nitrite and nitrate, being enhanced by the presence of NO2 during the sulfation of a BFS/HL sorbent. The addition of NaOH in this case promoted the formation of sulfates but became less important in raising the sorbent reactivities for sorbents except BFS. Without the presence of CO2/O2/NOx, the BFS/HL sorbents with ratios ≤70/30 had higher reactivities than HL, but with the presence of CO2/O2/NOx, HL had the highest value of SO2 capture among the BFS/HL and BFS/HL/NaOH sorbents tested. Placing the SO2 removal unit before the NOx removal unit in practical operations can take advantage of the enhancement effect of CO2/O2/NOx on increasing the Ca utilization and SO2 capture of the sorbent.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9012425

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 506–514

Titre :	Role of acidity in the ethylation of coking benzene with ethanol over nanosized HZSM-5
Type de document :	texte imprimé
Auteurs :	Sun, Linping, Auteur ; Xinwen Guo, Auteur ; Liu, Min, Auteur
Année de publication :	2010
Article en page(s) :	pp 506–514
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Ethylation Zeolites Thermogravimetry Dimethylpyridine.
Résumé :	Ethylation of coking benzene, the product of coke oven gas, with ethanol over nanosized HZSM-5 zeolites poisoned by 2,6-dimethylpyridine has been investigated in a fixed-bed reactor. Pyridine infrared (Py-IR), amonia temperature programmed desorption (NH3-TPD), thermogravimetry (TG), acidity titration with a Hammett indicator, and cyclohexane and n-hexane adsorption were used to characterize the changes in acidity and porosity of the nanosized HZSM-5 zeolites poisoned by 2,6-dimethylpyridine. Conversion and product distribution depend strongly on the degree of catalyst poisoning. The acidity−activity correlation indicates that acid sites with pKa < −3.0 are responsible for the ethylation of coking benzene and sites with pKa < 2.27 are responsibly for the thiophene conversion. The remaining acid sites, which are not active for the ethylation of coking benzene over the poisoned sample, act as active centers for ethanol dehydration to ethylene. 2,6-Dimethylpyridine not only adsorbs on the strong Brnsted acid sites but blocks the zeolite channels over the poisoned sample.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901218j

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 498–505

Titre :	Heterogeneous fenton catalyst supports screening for mono azo dye degradation in contaminated wastewaters
Type de document :	texte imprimé
Auteurs :	Rodrguez, A., Auteur ; Ovejero, G., Auteur ; Sotelo, J. L., Auteur
Année de publication :	2010
Article en page(s) :	pp 498–505
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Heterogeneous Catalyst Wastewater.
Résumé :	Degradation of acid orange II (AOII), a dye present in textile industry wastewater, by the heterogeneous Fenton process (HFP) was performed. In order to select an adequate support, heterogeneous Fenton catalysts were prepared using several materials such as carbon nanotubes, carbon nanofibers, activated carbon, hydrotalcite-like materials, mesoporous silica (MCM41), silica, silica xerogel, sepiolite, and zeolite USY, that were tested in the degradation of AOII as the model compound. Color, total organic carbon, chemical oxygen demand removal, and toxicity were studied in the process. The best catalyst was iron supported on sepiolite. The best performing catalytic material was used to investigate the influence of the presence of carbonate ions, pH, and reuse of catalyst. Also, a real textile wastewater was successfully treated with this catalyst.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901212m

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 490–497

Titre :	Catalytic hydrodechlorination of tetrachloroethylene over Pd/TiO2 minimonoliths
Type de document :	texte imprimé
Auteurs :	Gonzalez, Carlos A., Auteur ; Montes de Correa, Consuelo, Auteur
Année de publication :	2010
Article en page(s) :	pp 490–497
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Catalyst Hydrodechlorination Tétrachloroéthylène.
Résumé :	The gas phase catalytic hydrodechlorination (CHD) of tetrachloroethylene (TTCE) over 0.8% Pd/TiO2 (Hombikat uv-100) washcoated cordierite minimonoliths has been studied in the temperature range 120−180 °C. Experiments were carried out operating under differential regimes at a gas hourly space velocity (GHSV) of 0.45 (g min)/mL and using different concentrations of TTCE (300−1000 ppmv), hydrogen (0−10000 ppmv), ethane (0−850 ppmv), and hydrogen chloride (0−550 ppmv). The turnover frequency, specific rate constant, reaction order, and activation energy were determined. The pseudo-first-order Langmuir−Hinshelwood models adequately represent experimental results. The best adjustment corresponds to models featuring TTCE adsorption (associative or dissociative) as the limiting step. The CHD reaction is favored as TTCE and hydrogen concentrations are increased, while HCl negatively affects kinetic parameters. In order to study the causes of deactivation, fresh and used catalyst samples were characterized by nitrogen adsorption (BET), H2 chemisorption, thermogravimetric analysis (TGA), Fourier transform infrared (FTIR), and temperature-programmed oxidation coupled to mass spectrometry. Characterization results indicate that carbonaceous deposits were insignificant under reaction conditions, while the presence of HCl was the main cause of catalyst deactivation.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901027y

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 481–489

Titre :	Deactivation kinetics for direct dimethyl ether synthesis on a CuO−ZnO−Al2O3/γ-Al2O3 catalyst
Type de document :	texte imprimé
Auteurs :	Sierra, Irene, Auteur ; Erena, Javier, Auteur ; Andrés T. Aguayo, Auteur
Année de publication :	2010
Article en page(s) :	pp 481–489
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Kinetic Catalyst Dimethyl ether.
Résumé :	A kinetic model has been established for the deactivation of a CuO−ZnO−Al2O3/γ-Al2O3 catalyst in the direct synthesis of dimethyl ether. The model allows calculating the effect of the operating conditions and the evolution of component concentration in the reaction medium (dimethyl ether, methanol, paraffins, H2, CO, CO2, and H2O) with time on stream. The results of the model fit the experimental results in a wide range of conditions: 225−350 °C; 10−40 bar; space time, 0.1−68.0 (g of catalyst) h (mol of reactants)−1; molar ratio (H2/CO) in the feed, 2−4; time on stream, 30 h. The model considers the cause of deactivation to be coke deposition on the metallic function and that this coke is formed by degradation of oxygenates (dimethyl ether and methanol). The effect of water in the reaction medium has been quantitatively considered in the kinetic model, whose drawback is the attenuation of the methanol synthesis rate and whose benefit is the attenuation of deactivation by coke deposition. The kinetic model is useful for predicting the influence of water in the feed with syngas as a strategy to attenuate deactivation, which is insignificant for a H2O/(H2 + CO) molar ratio of around 0.20, although it causes a slight decrease in initial catalyst activity.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900978a

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 472–480

Titre :	Comparative study of two different hydrogen redistribution strategies along a fluidized-red hydrogen permselective membrane reactor for methanol synthesis
Type de document :	texte imprimé
Auteurs :	Rahimpour, M. R., Auteur ; Bayat, M., Auteur
Année de publication :	2010
Article en page(s) :	pp 472–480
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Hydrogen Permselective membrane reactor.
Résumé :	In this work, two different hydrogen redistribution strategies along a bubbling fluidized-bed hydrogen permselective membrane reactor have been compared. In the first strategy, fresh synthesis gas flows in the tube side of the fluidized-bed membrane reactor in cocurrent mode with reacting material in the shell side, so that more hydrogen is provided in the first segments of the reactor. In the second strategy, fresh synthesis gas flows in the tube side of the fluidized-bed membrane reactor in countercurrent mode with reacting material in the shell side, so that more hydrogen is provided in the last segments of the reactor. A dynamic two-phase theory in the bubbling regime of fluidization was developed to model and compare two strategies from different points of view. Comparison between cocurrent and countercurrent modes of operation shows that the reactor in the countercurrent configuration operates with higher conversion of methanol, longer catalyst life, and higher carbon dioxide removal, whereas the reactor in the cocurrent configuration operates with higher carbon monoxide removal, lower water production, and higher hydrogen permeation rate. Enhancement of the carbon dioxide removal in countercurrent mode and the carbon monoxide removal in cocurrent mode causes a lower environmental impact. The lower water production rate in cocurrent mode reduces catalyst recrystallization.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9005113

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 464–471

Titre :	Decomposition of perfluorinated ion-exchange membrane to fluoride ions using zerovalent metals in subcritical water
Type de document :	texte imprimé
Auteurs :	Hori, Hisao, Auteur ; Murayama, Misako, Auteur ; Sano, Taizo, Auteur
Année de publication :	2010
Article en page(s) :	pp 464–471
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Ion-exchange membrane Zerovalent metals.
Résumé :	The decomposition of Nafion NRE-212, a typical perfluorinated ion-exchange membrane used for fuel cells, in subcritical water was investigated. This is the first report of the decomposition of a perfluorinated ion-exchange membrane aimed at the development of a technique to recover the fluorine component for waste treatment. Although the membrane showed little decomposition in pure subcritical water, the addition of several zerovalent metals to the reaction system accelerated the membrane decomposition to F− ions, and the acceleration increased in the order Al < no metal < Zn < Cu Fe. When the membrane and iron powder were heated in subcritical water at 350 °C for 17 h, 73.2% of the fluorine content in the initial membrane was successfully transformed into F− ions. In addition to F− ions, trifluoroacetic acid and HCF(CF3)OC2F4SO3− were also detected in the reaction solutions as intermediates, and CO2 and CF3H were detected in the gas phase. Time profiles of the products suggest that one pathway of the decomposition of the membrane proceeded by decomposition of the pendant-chain part, followed by decomposition of the polymer backbone.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9004699

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 459–463

Titre :	Microwave pyrolysis of wood pellets
Type de document :	texte imprimé
Auteurs :	Robinson, J. P., Auteur ; Kingman, S. W., Auteur ; Barranco, R., Auteur
Année de publication :	2010
Article en page(s) :	pp 459–463
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Pyrolysis Wood Microwave pyrolysis.
Résumé :	The pyrolysis of wood pellets was investigated using a single-mode microwave cavity, and the dielectric properties of the wood were measured at temperatures up to 750 °C. Below 600 °C, the only microwave-absorbing phase within wood is water. This study has shown categorically that microwave pyrolysis can be achieved without the use of carbon-rich dopants and that the heating of water alone can be used to induce pyrolysis of wood. A number of potential mechanisms are discussed that relate to the power density within the heated material. The yield of bio-oil and biogas is a function of the heating rate and power density, and for the samples used in this study, a threshold power density of 5.0 × 108 W/m3 was found, below which microwave pyrolysis did not occur. The results and hypotheses presented in this article represent the first steps in understanding the fundamental mechanisms of microwave pyrolysis.
DEWEY :	660
ISSN :	0888-5858
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901336k

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 454–458

Titre :	Synthesis of zeolite of type A from bentonite by alkali fusion activation using Na2CO3
Type de document :	texte imprimé
Auteurs :	Ma, Hongchao, Auteur ; Yao, Quantong, Auteur ; Fu, Yinghuan, Auteur
Année de publication :	2010
Article en page(s) :	pp 454–458
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Zeolite A Hydrothermal method.
Résumé :	Optimization studies were carried out for the synthesis of zeolite A by a hydrothermal method using alkali-activated bentonite as raw material. The process of alkali fusion activation and optimization of the composition were studied by TG-DTA, XRD, and calcium ion exchange capacity. It was found that a mixture of additional alumina (aluminum hydroxide) and bentonite was converted to highly reactive sodium silicate, sodium aluminate, and aluminosilicate by alkali fusion activation using Na2CO3 at high temperature. Zeolite A with a maximum crystallinity of 82.7% and calcium ion exchange capacity of 302 mg of CaCO3/g was obtained at optimized conditions.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901205y

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 448–453

Titre :	Synthesis and UV absorption properties of 5,5′-methylenedisalicylic acid-intercalated Zn−Al layered double hydroxides
Type de document :	texte imprimé
Auteurs :	Cui, Guo-Jing, Auteur ; Xu, Xiang-Yu, Auteur ; Lin, Yan-Jun, Auteur
Année de publication :	2010
Article en page(s) :	pp 448–453
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	UV absorption Methylenedisalicylic Hydroxides.
Résumé :	A UV absorber, 5,5′-methylenedisalicylic acid (MDSA), has been intercalated into a ZnAl−NO3 layered double hydroxide (LDH) by an ion-exchange method. After intercalation of MDSA, the basal spacing in the LDH increased from 0.90 to 1.53 nm, suggesting that the MDSA anions were arranged in the interlayer galleries of ZnAl−MDSA LDH as a tilted monolayer arrangement of dianions. Infrared spectroscopy and thermogravimetry and differential thermal analysis (TGA−DTA) curves revealed the presence of a complex system of supramolecular host−guest interactions. The thermal stability of the intercalated UV absorbent was investigated by TGA−DTA, which showed that the thermostability was markedly enhanced after intercalation into the LDH host. After addition of 1 wt % ZnAl−MDSA LDH to polypropylene (PP), the resistance of the polymer to UV degradation was significantly improved.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901151c

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 443–447

Titre :	Identification and quantification of related impurities in 2-chloroethyl phenyl sulfide for industrial use
Type de document :	texte imprimé
Auteurs :	Qiao, Jun-Qin, Auteur ; Bao, Yan-Chu, Auteur ; Yang, Ji-Hong, Auteur
Année de publication :	2010
Article en page(s) :	pp 443–447
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Chloroethyl Phenyl Sulfide.
Résumé :	A combination of gas chromatography and mass spectrometry (GC-MS) was applied to separate and identify the relative substances in 2-chloroethyl phenyl sulfide (CEPS), an industrial intermediate formed in the synthesis of sulfinpyrazone. Six impurities, including 1,2-dichloroethane, thiophenol, diethylmalonate, tributylamine, diphenyl disulfide, and 1,2-dithiophenylethane, were verified. According to the production technique, the sources of all of these related impurities were analyzed, and some practical suggestions are put forward for their removal from or avoidance in CEPS. Furthermore, a technique involving high-performance liquid chromatography with UV detection (HPLC-UV) was developed to separate and determine thiophenol, the key impurity in CEPS. A linear standard curve was obtained for thiophenol in concentrations between 2.65 × 10−4 and 0.106 mg mL−1, and the detection limit of thiophenol was 1.32 × 10−4 mg mL−1. Excellent precision and accuracy were shown from the method validation, with relative standard deviations (RSDs) of less than 1.5% for both intra- and interday measurements, and recoveries between 95.4% and 97.0%. Based on the above merits, the proposed procedures of GC-MS and HPLC-UV can provide specific information on the impurities in CEPS, and therefore, these methods can be well applied to quality control in the industrial production of CEPS.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9014167

Industrial & engineering chemistry research / Paul, Donald R. . Vol. 49 N° 2

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