Catalogue en ligne Bibliothèque Ecole Nationale Polytechnique d'Alger

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp 10894–10901

Titre :	Comparison among pitzer-type models for the osmotic and activity coefficients of strong electrolyte solutions at 298.15 K
Type de document :	texte imprimé
Auteurs :	F. Perez-Villasenor, Auteur ; S. Carro-Sanchez, Auteur
Année de publication :	2011
Article en page(s) :	pp 10894–10901
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Thermodynamic properties Electrolyte solution Strong electrolyte Activity coefficient Modeling
Résumé :	In this work three Pitzer-type models were compared: the original one, the Archer model (an extended Pitzer model) with ionic strength dependence in the third virial coefficient, and the PIH model that uses as an adjusting parameter the closest approach constant. The performance of these models in correlating the osmotic and activity coefficient of 1:1, 1:2, 1:3, 1:4, 2:1, 2:2, 3:1, 3:2, and 4:1 aqueous electrolyte solutions was tested using experimental data sets for 245 single electrolyte aqueous solutions. The absolute average percentage deviations were 0.78, 1.18, and 3.56% for the Archer, PIH, and Pitzer models, respectively.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523909

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10889–10893

Titre :	Electrochemical synthesis of peroxyacetic acid using conductive diamond electrodes
Type de document :	texte imprimé
Auteurs :	Salvador Cotillas, Auteur ; Ana Sanchez-Carretero, Auteur ; Pablo Canizares, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10889–10893
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Electrodes
Résumé :	In this work, the synthesis of peroxyacetic acid and peroxoacetate salts by electrolysis with conductive-diamond anodes is described, using three different raw materials: ethanol, acetaldehyde, and sodium acetate. Results show that peroxyacetic acid is produced at significant concentrations during the electrolyses of the three raw materials, although sodium acetate achieves the highest efficiency and, at the same time, the smallest carbon mineralization. Acetaldehyde behaves as a good raw material during a first stage but, afterward, it catalyzes the decomposition of peroxoacetate to the acetate anion. Moderate current densities and slightly alkaline pH seems to promote the synthesis of peroxyacetic acid and to restrain raw matter mineralization.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523908

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp 10883–10888

Titre :	Monitoring the thermal elimination of infiltrated polymer from AAO templates : an exhaustive characterization after polymer extraction
Type de document :	texte imprimé
Auteurs :	Iwona Blaszczyk-Lezak, Auteur ; Jon Maiz, Auteur ; Javier Sacristan, Auteur
Année de publication :	2011
Article en page(s) :	pp 10883–10888
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Surveillance
Résumé :	Porous anodic aluminum oxide (AAO) templates have been demonstrated to be an easy way to prepare one-dimensional polymeric nanostructures by polymer infiltration into the nanopores. The opportunity to reuse the AAO templates significantly reduces the cost and time of production. Through treatment of infiltrated polyethylene oxide (PEO) into AAO templates at 450 °C, we were able to remove the entire polymer from the pores of templates. The completely elimination of PEO is confirmed by confocal Raman spectroscopy, wide-angle X-ray diffractometry (WAXD), and thermogravimetric analysis (TGA). This methodology can have wider application, since the adhesion coefficient is not as an important issue as it was in mechanical methods reported in the literature, and, therefore, it reduces cost and time significantly.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523907

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10878–10882

Titre :	Bifunctional Pd/Cr2O3–ZrO2 catalyst for the oxidation of volatile organic compounds
Type de document :	texte imprimé
Auteurs :	Ling-Yun Jin, Auteur ; Rui-Hong Ma, Auteur ; Jian-Jun Lin, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10878–10882
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Volatile organic compound Oxidation Catalyst
Résumé :	This study focuses on developing a catalyst for the removal of volatile organic compounds (VOCs) accompanied chlorinated volatile organic compounds (CVOCs). By a combination of deposition-precipitation and impregnation methods, a Pd/Cr2O3―ZrO2 catalyst was prepared and tested for catalytic oxidation of dichloromethane, ethyl acetate, and toluene. It was found that the Pd/Cr2O3―ZrO2 catalyst are very active for the catalytic oxidation of all these three different organics, due to the bifunctional catalysis of Pd and Cr. By comparing the catalytic performance of Cr2O3―ZrO2, Pd/ZrO2, and Pd/Cr2O3―ZrO2 catalysts, it suggested that the Cr species are more active for dichloromethane and ethyl acetate oxidation, while the Pd species play a very important role in toluene Oxidation.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523906

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10872-10877

Titre :	A systematic approach for the synthesis of highly controllable mass exchange networks
Type de document :	texte imprimé
Auteurs :	Abeer M. Shoaib, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10872-10877
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Mass transfer
Résumé :	It is known that the lack of controllability is the major cause of catastrophic events, energy inefficiency, and the generation of "off-spec" products to be treated as waste or to be recycled. This paper addresses the problem of synthesizing a mass exchanger network (MEN) that satisfies the control-related criteria "controllability". In this work, four simple heuristic rules are introduced for MEN synthesis. Applying such simple rules in the matching step results in a highly controllable network, without requirement of sequential integration that would give rise to a time-consuming and tedious procedure requiring extensive iteration. Two alternative case studies are introduced to demonstrate the effectiveness of the proposed procedure.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523905

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10865-10871

Titre :	Influence of coal feed size on the performance of air dense medium fluidized bed separator used for coal beneficiation
Type de document :	texte imprimé
Auteurs :	Satyabrata Mohanta, Auteur ; Sudipto Chakraborty, Auteur ; B. C. Meikap, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10865-10871
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Separator Fluidized bed Fluidization Coal
Résumé :	In gravity separation operation, the probability of a coal particle to appear in the product stream or in the refuse stream is a strong function of its size. Improper selection of feed size may lead to significant reduction in efficiency of the separation unit. Available literature conforms that the separation efficiency of an air dense medium fluidized bed separator, which is a gravity separation operation, decreases with feed coal size, but determination of appropriate feed size range, for efficient operation of this separator, still remains as a challenge. In this paper, the effect of feed size on the separation performance is investigated and an attempt has been made to quantify the optimum size range over which the separator can operate satisfactorily. The performance of the equipment is evaluated in two steps, namely, sharpness of separation affected by the washing unit and the efficiency of the washing operation. Predictive model equations are also proposed for describing the relation between sharpness of separation and feed size. Four Indian coal samples of different washability characteristics are considered for this investigation. Preliminary results show that the air dense medium fluidized bed separator performance is quite satisfactory for the feed coal within the 50―15 mm size range.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523904

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10859-10864

Titre :	Theoretical study of the influence of mixing on the selective noncatalytic reduction process with CH4 or H2 addition
Type de document :	texte imprimé
Auteurs :	Qingxi Cao, Auteur ; Hui Liu, Auteur ; Shaohua Wu, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10859-10864
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Mixing
Résumé :	This work presents a theoretical study of the influence of mixing on NO removal from flue gas by the selective noncatalytic reduction (SNCR) process with CH4 or H2 addition, using an elementary reaction mechanism together with a simple approach for mixing proposed previously. The results show that the mixing process affects NO reduction significantly. For he SNCR process with CH4 addition, the mixing process narrows the temperature window at the high temperature side. For the case with H2 addition, besides the temperature window getting narrower, the maximum NO removal efficiency declines notably, and NH3-slip near the optimal temperature rises. This discovery explains the experimental results in the literature reasonably, and it indicates that fast mixing is essential to gain good performance, while H2 additive is used in practical application. Furthermore, the-reason for the distinct effects of mixing on the two DeNOx processes was revealed by theoretical analysis.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523903

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10850-10858

Titre :	Modeling the composition of crude oil fractions using constrained homologous series
Type de document :	texte imprimé
Auteurs :	Steven P. Pyl, Auteur ; Zhen Hou, Auteur ; Kevin M. Van Geem, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10850-10858
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Crude oil Modeling
Résumé :	Composition anodeling using coastrained homologous series permits the derivation of the detailed composition of complex mixtures starting from a limited set of mixture bulk properties. By imposing various constraints, the number of unknowns is drastically reduced. Probability density functions are imposed on both the carbon number distribution in each homologous series of components and on the structural attribute distributions. Validation, based on detailed compositional information, shows that the use of gamma distributions to constrain the mixture composition results in an adequate approximation of the experimentally measured composition. The latter was obtained for two middle distillates and a heavy gas oil using advanced analytical techniques.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523902

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10843–10849

Titre :	Modeling the influence of particulate protein size on hydrolysis in anaerobic digestion
Type de document :	texte imprimé
Auteurs :	Saad Aldin, Auteur ; George Nakhla, Auteur ; Madhumita B. Ray, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10843–10849
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Anaerobic digestion Hydrolysis Modeling
Résumé :	Batch experiments were performed to investigate the effect of particulate protein size on the hydrolysis of casein in anaerobic degradation. Whereas particle size did not affect the ultimate protein degradation efficiency, the hydrolysis rate coefficient increased from 0.034 to 0.298 day―1 with a change in specific surface area from 0.01 to 0.192 m2/g. The maximum rate of methane production increased from 6 to 14 mL of CH4 per gram of COD added per day with the same change in specific surface area, although the ultimate volume of methane produced was approximately the same despite the change in specific surface area. A mathematical relationship between the hydrolysis rate coefficient and the specific surface area was developed, and a new hydrolysis equation was proposed and verified.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523901

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10833-10842

Titre :	Prediction of the effective area in structured packings by computational fluid dynamics
Type de document :	texte imprimé
Auteurs :	Saeed Shojaee, Auteur ; Seyyed Hossein Hosseini, Auteur ; Arash Rafati, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10833-10842
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Computational fluid dynamics Ordered packing Prediction
Résumé :	Careful examination of the correlations for the effective interfadal area of the structured packed columns in the literature reveals considerable discrepancies in the estimated areas and the associated gas velocities. In this study, a volume of fluid multiphase-flow model for two adjacent sheets of a Gempak 2A structured packing was used to investigate the effect ofgas and liquid velocities on the effective area of the packing sheets. The three-dimensional computational fluid dynamic (CFD) results showed that the gas and liquid flow rates play significant roles in the effective interfacial area of the packed bed. In particular, the effective area increases as the flow rates of both phases increase. The simulation results were compared with the existing correlations for the effective area, and it was found that the Brunazzi model exhibits good agreement with the CFD results in comparison with the existing correlations. Using the CFD model, the minimum flow rate 109.8 m3/m2·h for which the entire surface covered by the liquid phase was determined The simulation results showed that the CFD can be used as an effective tool to provide information on the details of the gas and liquid flows in complex packing geometries.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523900

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10824-10832

Titre :	Minimum energy dissipation under cocurrent flow in packed beds
Type de document :	texte imprimé
Auteurs :	Talgat A. Akramov, Auteur ; Petr Stavarek, Auteur ; Vladimir Jiricny, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10824-10832
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Packed bed Cocurrent flow Energy dissipation Minimum energy
Résumé :	Functional analysis of mass balances on gas and liquid, and pressure drop equations describing the concurrent flow in packed beds has yielded two criteria. Positive values of these criteria has been shown sufficient to achieve energy savings by synchronized periodic pulsations of inlet gas and liquid velocities or by liquid velocity only compared to the situation under the same mean steady inlet phase velocities. This, however, is not the case of pulsation by gas inlet velocity alone. The developed criteria have been evaluated from data obtained by experimental measurement of liquid holdup and gas pressure drop in a column 0.05 m in diameter packed to 1 m by 0.003 m glass spheres using water/air and toluene/air system. Our experiments showed these criteria to be fulfilled in the whole domain of gas and liquid velocities tested. Evaluation of the energy savings under pulsations relative to the steady state operation showed that the savings for water/air system may reach up to 4% with the maximum in region of high and intermediate liquid velocities and low gas velocities. For the toluene/air system the savings are somewhat lower and occur in the same velocity domain.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523899

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10811-10823

Titre :	Markov chain modeling of fluidized bed granulation incorporating simultaneous aggregation and breakage
Type de document :	texte imprimé
Auteurs :	Muammer Catak, Auteur ; Kevin Cronin, Auteur ; Dario Medina-Tellez, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10811-10823
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Aggregation Granulation Fluidized bed Fluidization Modeling
Résumé :	Fluidized bed granulation to achieve particle size enlargement is a significant process in chemical engineering. A key aim of the modeling of such a system is prediction of the evolution of the particle size distribution with time. The traditional tool to achieve this is through the use of population balances. This Article proposes an alternative modeling approach of Markov chain, which is a well-known tool in stochastic theory. Specifically, in this Article, it is employed to model bottom spray Wurster type fluidized bed granulation and a one-dimensional chain where the particle size is the state variable was used. Three important elements of Markov chains are the initial state vector a(t), the transition time step τ, and the transition matrix P. The transition matrix was assembled from consideration of breakage and aggregation dynamics. Experiments were conducted to validate the approach using glass beads as the elementary particles and polyethylene glycol as the liquid binder. From the results, it is shown that the Markov chain method is an efficient and accurate tool to analyze the particle size evolution of a size enlargement process.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523898

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10800–10810

Titre :	Ionic liquid screening for ethylbenzene/styrene separation by extractive distillation
Type de document :	texte imprimé
Auteurs :	Mark T.G. Jongmans, Auteur ; Boelo Schuur, Auteur ; Andre B. de Haan, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10800–10810
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Ionic liquid
Résumé :	The separation of ethylbenzene from styrene by distillation is very energy-intensive, because of the low relative volatility (1.3–1.4). Extractive distillation is a promising alternative to separate the close boiling mixture, in which the solvent selection is crucial for the process feasibility. In this work, an ionic liquid screening study by liquid–liquid equilibrium (LLE) experiments has been performed to investigate whether ionic liquids (ILs) show potential to separate ethylbenzene from styrene by extractive distillation. The screening method by LLE experiments was validated by VLE experiments for several ILs. The performance of the ILs was compared with the benchmark solvent sulfolane, which displays a selectivity of 1.6. Several ILs outperform sulfolane with selectivities up to 2.6. From the results of the LLE experiments, it was concluded that there is a clear tradeoff between capacity and selectivity. ILs with a high capacity usually have a low selectivity, whereas ILs with high selectivity exhibit low capacity. Both cation and anion structure strongly influence the performance. The highest selectivities (2.4–2.6) were obtained with ILs containing aromatic cations, and anions with localized electrons. The largest capacities (0.45–0.6 for styrene) were obtained for ionic liquids with delocalized electrons in the anion and large alkyl chain length in both cation and anion.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie2011627

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10792-10799

Titre :	Lignosulfonate separation using preparative column chromatography
Type de document :	texte imprimé
Auteurs :	Xinping Ouyang, Auteur ; Pan Zhang, Auteur ; Xueqing Qiu, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10792-10799
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Column chromatography
Résumé :	A two-step chromatographic process was developed for the fractionation of lignosulfonate (LS), a main component of sulfite effluence. LS fractions with low polydispersity were obtained, which enables detailed investigation into the relationship between structure and property of LS with different molecular weight (Mw). Sephacryl S-100 was used for LS separation in the first step, and then Sephadex LH-20 and Sephacryl S-100 were chosen for further separation of LS fractions with Mw below and above 6000 Da, respectively. Although the mechanism of column chromatographic separation of LS was mainly dependent on its molecular size, 0.20 mol/L of NaCl or NaNO3 solution was needed in the mobile phase at pH 5.7 to mirtimize electrostatic interaction and polyelectrolyte effect. Compared with the polyelectrolyte effect, the electrostatic interaction was more important in the LS separation. Because the LS fractions of higher Mw had a characteristic of low negative charge, a mobile phase with high flow rate and high pH value was suitable for separating LS fractions with high Mw.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523896

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp 10784–10791

Titre :	Study of glutamate-modified cellulose beads for Cr(III) adsorption by response surface methodology
Type de document :	texte imprimé
Auteurs :	Jing Liu, Auteur ; Min Yan, Auteur ; Yong-Kui Zhang, Auteur
Année de publication :	2011
Article en page(s) :	pp 10784–10791
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Cellulose ionic liquid Adsorption
Résumé :	A cellulose-based adsorbent was prepared from a cellulose–ionic liquid solution by emulsification followed by modification with glutamic acid for Cr(III) adsorption from aqueous solution. Response surface methodology (RSM) coupled with central composite design (CCD) was employed to optimize the adsorption process to ensure high adsorption efficiency. Three independent variables [initial Cr(III) concentration, pH, and adsorbent dose] were coded as x1, x2, and x3 at five levels (−1.68179, −1, 0, 1, −1.68179), and a second-order polynomial regression equation was then derived to predict the responses. The standardized effects of the independent variables and their interactions were tested by preparing a Pareto chart. Analysis of variance (ANOVA) showed that a high coefficient of determination value (R2 = 0.9959) and a satisfactory predicted second-order regression model were achieved in the study. Therefore, the optimum conditions for Cr(III) adsorption were established, and the optimum values of the selected variables were obtained by solving the quadratic regression and by analyzing the response surface contour plots. Under the optimum conditions, four sets of experimental trials for Cr(III) adsorption rate were performed, with results that were very close to the predicted values.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie200857n

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10778-10783

Titre :	Flotation and surface behavior of cassiterite with salicylhydroxamic acid
Type de document :	texte imprimé
Auteurs :	Wenqing Qin, Auteur ; Yangbao Xu, Auteur ; Hui Liu, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10778-10783
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Flotation
Résumé :	The flotation and surface interaction of cassiterite with salicylhydroxamic acid have been investigated in this paper. The results showed that recovery of cassiterite with salicylhydroxamic acid was high at a neutral pH, with the maximum recovery occurring at ca. pH 6.5. When the size of cassiterite is less than 74 μm, coarse particles showed better flotability than the fine ones. The adsorption of salicylhydroxamic acid was also high at a neutral pH. The isoelectric point of cassiterite showed an acidic shift in the presence of salicylhydroxamic acid. A chelate was identified on the cassiterite surface. The results of the adsorption, electrophoretic mobility, and IR spectrum of cassiterite indicated that the adsorption on the cassiterite surface included both physical and chemical adsorption. On the basis of the experimental results, a complex multilayer adsorption model was proposed to illustrate the adsorption on the surface of cassiterite.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523894

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10765-10777

Titre :	Ion-exchange membrane electrodialysis of saline water and Its numerical analysis
Type de document :	texte imprimé
Auteurs :	Yoshinobu Tanaka, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10765-10777
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Membrane separation Numerical simulation Numerical analysis Electrodialysis Ion exchange membrane
Résumé :	A computer simulation program was developed for a continuous saline water electrodialysis process. A practical-scale electrodialyzer was operated for concentrating seawater, and its performance was observed. The operating results of the electrodialyzer were computed by using the operating conditions as input for the program. The computed data were generally the same as the observed data. Thus, the program enables the semiquantitative discussion of the performance of a practical-scale electrodialyzer. In addition, (1) the current density distribution; (2) the electric resistances of a membrane pair, a desalting cell, and a concentrating cell; (3) the pressure drops in a desalting cell and a concentrating cell; and (4) the limiting current density of an electrodialyzer are discussed.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523893

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10755-10764

Titre :	Activity coefficients of organic solutes at infinite dilution in ionic liquids.1. 1-hexyl-3-methylimidazolium hexafluorophosphate and 1-octyl-3-methylimidazolium hexafluorophosphate and their application to alkane/aromatic and aromatic/aromatic hydrocarbon separation
Type de document :	texte imprimé
Auteurs :	Yi Li, Auteur ; Li-Sheng Wang, Auteur ; Yun-Xia Feng, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10755-10764
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Thermodynamic properties Ionic liquid Infinite dilution Activity coefficient
Résumé :	Activity coefficients at infinite dilution, γ∞i,3, for organic solutes (alkanes, alkenes, alkyl benzenes, alcohols, chloromethanes, acetonitrile, ethyl acetate, dioxane, tetrahydrofuran, and acetone) in 1-hexyl-3-methylimidazolium hexafluorophosphate [HMIM][PF6] and 1-octyl-3-methylimidazolium hexafluorophosphate [OMIM][PF6] have been determined using gas-liquid chromatography at temperatures from 303.15 to 363.15 K with the ionic liquids as the stationary phase. The partial molar excess enthalpies at infinite dilution of the ionic liquids were calculated for the solutes from the temperature dependence of the experimental activity coefficients at infinite dilution. The solubility parameters of ionic liquids were also determined by the regular solution theory. The selectivities of various ionic liquids for the alkane/aromatic hydrocarbon and aromatic/aromatic were summarized from literature and calculated from γ∞i,3.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523892

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10744-10754

Titre :	Heat integration by multiple hot discharges/feeds between plants
Type de document :	texte imprimé
Auteurs :	B. J. Zhang, Auteur ; X. L. Luo, Auteur ; Q. L. Chen, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10744-10754
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Heat recovery
Résumé :	Some independent plants making up a chemical or petrochemical site are linked by process streams. Linking process streams are, in general, cooled in up-plants and reheated in down-plants to satisfy process requirements. These streams, even more, travel from up-plants to storage tanks and, then, to down-plants, which results in low energy-use efficiency. Up-plants with multiple hot discharges and down-plants with multiple hot feeds are proposed in this paper, and a T―Qgraphic method is presented to target the temperature of multiple hot discharges/feeds between plants. The T-Q diagram is composed of a grand composite curve (GCC) and a composite curve that only involves process streams employed for hot discharge/feed. A mixed integer linear programming (MILP) model is formulated to minimize the total hot and cold utilities of up- and down-plants and to solve the temperature of hot discharge/feed and the heat transfer between plants. Some examples are utilized to demonstrate the performance of the presented method for multiple hot discharges/feeds between plants. Results show an obvious decrease in the total hot and cold utilities of up- and down-plants, along with less investment for equipment.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523891

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10730–10743

Titre :	Short-cut method for the design of reactive distillation columns
Type de document :	texte imprimé
Auteurs :	Marcelino Carrera-Rodriguez, Auteur ; Juan Gabriel Segovia-Hernandez, Auteur ; Adrian Bonilla-Petriciolet, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10730–10743
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Distillation column Distillation with reaction Design
Résumé :	The design of reactive distillation (RD) has received significant attention because of the technological and economic advantages obtained from the simultaneous occurrence of reaction and separation. Although the advantages of RD are well-documented in the literature, the commercial applications of RD are still limited because of the control and operation complexity of these separation systems and the need for improved software tools to reliably model and design RD columns. In this study, a robust short-cut method for the design of multicomponent reactive distillation is presented. This method is based on distillation lines and tray-by-tray calculations defined in terms of reaction-invariant composition variables. Our method provides the number of theoretical stages, the operating reflux ratio, the feed tray location, and the top or bottom flow. We use three case studies to demonstrate the effectiveness of the proposed strategy, namely, the reactive systems for the syntheses of ETBE and MTBE in the presence of inert components and of TAME without inert components. The results obtained with our strategy show good agreement with those obtained using the rigorous model of the commercial simulator AspenONE Aspen Plus.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523890

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10717-10729

Titre :	Economic and environmental assessment of alternatives to the extraction of acetic acid from water
Type de document :	texte imprimé
Auteurs :	Norberto Garcia, Auteur ; Jose A. Caballero, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10717-10729
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Environment impact
Résumé :	A comparison was made between conventional binary distillation and four feasible alternatives flowsheets to separate acetic acid from water attending to both economic and environmental criteria. All extraction steps use diethyl ether as an extractant. Our goals were, first, to estimate the economic and environmental incentives for each of the alternatives proposed in order to understand the trade-offs associated with each system and second, to show how, in some flowsheets, it is possible to rigorously decompose the system and perform detailed optimization without the necessity of simultaneous optimization of all the equipment implied in the flowsheet. To carry out the economic evaluation, two simple criteria were used: Economic Potential and Total Annual Cost These parameters were chosen because they can be used at various stages in the chemical plant design without the necessity of a complete picture of the industrial process. The environmental impacts are measured through the Ecoindicator-99 methodology, which reflects the advances in the damaged-oriented methodology recently developed for Life Cycle Assessment. For each of the alternatives, detailed optimization was performed to determine the Pareto's individual curves using the ε-constraint method. With the individual Pareto curves, it is also possible to obtain the compound Pareto's curve, and to then superimpose the individual Pareto's curves associated with the five alternatives to identify the trade-offs of this multiobjective optimization and ultimately determine the best alternatives, and even their optimum operational conditions.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523889

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10707-10716

Titre :	Two-tier search strategy to identify nominal operating conditions for maximum flexibility
Type de document :	texte imprimé
Auteurs :	Vincentius Surya Kurnia Adi, Auteur ; Chuei-Tin Chang, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10707-10716
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Flexibility Operating conditions
Résumé :	Traditionally, design and control issues have been addressed separately at different stages in the life cycle of a chemical plant. The process parameters are often selected in an ad hoc fashion during the design stage, and some of them later become the nominal set-point conditions in actual plant operation. The uncertain online disturbances associated with each set of operating conditions usually vary within a specific range centered at the nominal value. Because these arbitrarily chosen parameter values do not always result in the highest level of operational flexibility, it is thus desirable to develop a systematic method to optimally stipulate the nominal operating conditions of an existing process for maximum flexibility. The well-recognized flexibility index model is used in this work to evaluate system resiliency based on fixed nominal conditions, and a direct search method (differential evolution) is performed accordingly to identify the best candidates. Two examples are presented in this article to demonstrate the impacts of nominal settings and the effectiveness of the proposed optimization approach.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523888

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10696-10706

Titre :	Scale-up of a pharmaceutical roller compaction process using a joint-Y partial least squares model
Type de document :	texte imprimé
Auteurs :	Zheng Liu, Auteur ; Mark-John Bruwer, Auteur ; John F. MacGregor, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10696-10706
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Modeling Partial least squares Compaction Scale effect Extrapolation
Résumé :	Garda-Munoz et al. [Garcia-Munoz, S.; Kourti, T.; MacGregor, J. F. Chemom. Intell. Lab. Syst. 2005, 79, 101―114] proposed a new latent variable regression methodology, joint-Y partial least squares (JYPLS), for product transfer between plants. In this paper, this method is used for product scale-up from a type of laboratory-scale roller compactor, a Fitzpatrick IR220, to a type of full-scale roller compactor, a Fitzpatrick IR520, in the pharmaceutical industry. AJYPLS model is first built with the data set collected from historical experiments on these two types of compactors. The JYPLS model relates API mass fraction, excipient mass factions, and roller compaction process measurements to ribbon properties. A constrained optimization is then formulated to invert the JYPLS model to find the key process settings of the Fitzpatrick IR520 to make the same quality of ribbon using the same raw materials formulation as the ribbon that had been produced on the Fitzpatrick IR220.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523887

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10681–10695

Titre :	Conceptual synthesis of gasification-based biorefineries using thermodynamic equilibrium optimization models
Type de document :	texte imprimé
Auteurs :	Douglas H. S. Tay, Auteur ; Houssein Kheireddine, Auteur ; Denny K. S. Ng, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10681–10695
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Modeling Optimization Thermodynamic equilibrium Gasification
Résumé :	An integrated biorefinery is a processing facility that converts biomass into a wide range of biochemical products and also provides a sustainable supply of biofuels and energy. One of its critical features is the ability to handle a wide variety of biomass feedstocks and the capacity to produce a portfolio of products through multiple conversion technologies. The gasification process is recognized as a promising option for initial processing of biomass, as it is a robust thermal conversion process. The composition of syngas, especially the ratio ofH2to CO, is crucial when the syngas is further converted to liquid fuels and chemicals. To optimize the production of syngas for application in an integrated biorefinery, a systematic approach is needed to design the system and predict its performance. In this work, a modular optimization approach to link a stoichiometric equilibrium model of biomass gasification and structural models of synthesis processes is developed. In this approach, all model components are solved simultaneously. The approach is used to evaluate the equilibrium composition of syngas, the optimum operating temperature, and the required types and amounts of oxidants. Two case studies are used to illustrate the approach. A sensitivity analysis is then performed to assess the most significant factors affecting the process economics in these examples.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523886

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10665-10680

Titre :	Hybrid mathematical programming discrete-event simulation approach for large-scale scheduling problems
Type de document :	texte imprimé
Auteurs :	Pedro M. Castro, Auteur ; Adrian M. Aguirre, Auteur ; Luis J. Zeballos, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10665-10680
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Scheduling Mathematical programming
Résumé :	This article presents a new algorithm for industrially sized problems that, because of the large number of tasks to schedule, are either intractable or result in poor solutions when solved with full-space mathematical programming approaches. Focus is set on a special type of multistage batch plant featuring a single unit per stage, zero-wait storage policies, and a single transportation device for moving lots between stages. The algorithm incorporates a mixed-integer linear programming (MILP) continuous-time formulation and a discrete-event simulation model to generate a detailed schedule. More precisely, three stages are involved: (i) finding the best processing sequence, assuming that the transportation device is always available; (ii) generating a feasible schedule, taking into account the shared transportation resource; (iii) improving the schedule through a neighborhood search procedure. Relaxed and constrained versions of the full-space MILP are involved in stages (i) and (iii) with the simulation model taking care of stage (ii). Several examples are solved to illustrate the capabilities of the proposed method with the results showing better performance when compared to other published approaches. The balance between solution quality and total computational effort can easily be shifted by changing the number of lots rescheduled per iteration.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523885

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10652-10664

Titre :	Monte carlo simulation for aggregative mixing of nanoparticles in two-component systems
Type de document :	texte imprimé
Auteurs :	Haibo Zhao, Auteur ; Frank Einar Kruis, Auteur ; Chuguang Zheng, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10652-10664
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Nanoparticle Mixing Monte Carlo method
Résumé :	Gas-to-particle synthesis under high temperature is one of the most important methods for producing multicomponent nanoparticles. The volume enlargement of particles due to aggregation accompanies the component mixing within particles in a nonreactive system. To tailor nanocomposites, it is essential to gain an insight into the dynamic evolution of compositional distributions. In this paper, the differentially weighted Monte Carlo (DWMC) method for population balance modeling is used to simulate the process of aggregative mixing. On the methodological end, a new shift action is proposed to regulate a limited number of simulation particles to be distributed as homogeneously as possible over high-dimensional and inhomogeneous joint space of multiple components, where some simulation particles in less-populated regions are split into more simulation particles in order to increase sample space for stochastic statistics and then fatigue against statistical noise, at the same time a certain number of simulation particles in densely populated regions are randomly removed from the simulation to reduce computational demands. The DWMC with the new shift action is used to simulate the aggregative mixing process of bicomponent nanoparticles with compositional-independent or -dependent Brownian coagulation kernel in the free-molecular regime. It is found that the compositional distributions satisfy self-preserving formulation as the particle size distribution in monocomponent systems; and the extent of the time evolution of the degree of mixing (the mass-normalized power density of excess component A) corresponds with that of self-preserving distributions. The compositional distributions and the degree of mixing predicted by the DWMC agree well with theoretical models, while the constant-number method (using equally weighted simulation particles) fails in the more advanced stages of aggregative mixing.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523884

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10643–10651

Titre :	Development of soft sensor models based on time difference of process variables with accounting for nonlinear relationship
Type de document :	texte imprimé
Auteurs :	Hiromasa Kaneko, Auteur ; Kimito Funatsu, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10643–10651
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Process variables
Résumé :	Soft sensors are widely used to estimate process variables that are difficult to measure online. Though regression models are reconstructed with new data to adapt changes of the plants, some problems remain in practice. Hence, it is attempted to construct soft sensor models based on the time difference of an objective variable and that of explanatory variables for reducing the effects of deterioration with age such as the drift and gradual changes in the state of plants. In this paper, we have proposed to construct time difference models after modeling nonlinear relationship between and among process variables. Variables obtained by physical models or those calculated by statistical nonlinear regression methods are used to consider the nonlinearity, and then, a time difference model is constructed including these variables. We applied these methods to the actual industrial data obtained during an industrial polymer process and confirmed the usefulness of the proposed methods.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie200692m

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10630–10642

Titre :	Multicriteria optimization model for supply process problem under provision and demand uncertainty
Type de document :	texte imprimé
Auteurs :	Maria Analia Rodriguez, Auteur ; Aldo Vecchietti, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10630–10642
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Uncertainty Modeling Optimization
Résumé :	Supply processes play an important role in customer satisfaction and company costs. The main characteristics of this problem are given by several decisions that follow a hierarchical structure and a very uncertain context, conditioning the success of the solutions proposed. Two significant sources of uncertainty are considered in this work, namely, provision and demand, both modeled as exogenous variables with random behavior. An optimization model is formulated to reduce the effects of the uncertainty in the company supply process. Because of the problem complexity, a multicriteria model is required to bring a comprehensive solution. Several Pareto-optimal solutions are obtained through application of the ε-constraint technique. The original formulation is a nonconvex one that is then transformed to obtain a disjunctive linear model that guarantees a global result.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523882

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10615-10629

Titre :	New product development with discrete event simulation : application to portfolio management for the pharmaceutical industry
Type de document :	texte imprimé
Auteurs :	J. L. Perez-Escobedo, Auteur ; C. Azzaro-Pantel, Auteur ; L. Pibouleau, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10615-10629
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Pharmaceutical industry Product development
Résumé :	New product development (NPD) constitutes a challenging problem in the pharmaceutical industry. Formally, the NPD problem can be stated as follows: Select a set of R&D projects from a pool of candidate projects to satisfy several criteria (e.g., economic profitability, time to market) while coping with the uncertain nature of the projects. More precisely, the recurrent key issues are to determine the projects to be developed, together with the order in which they enter the pipeline and the corresponding resource allocation. In this context, this work presents the development and implementation of a discrete event simulator for drug portfolio management based on object-oriented techniques and used as a tool for evaluating each drug or sequence of drugs. Evaluation methods based on bubble charts are used for selecting the best drugs according to the considered evaluation criteria. Imprecision modeling has been tackled in two ways: a classical probability approach and an interval-based one. Both approaches are illustrated by a numerical example, which shows that the tendencies obtained by the interval-based approach can be difficult to interpret for the decision maker, because of the growing uncertainty along the pipeline. In addition, the risk, which is taken into account through failure probability for some stages and which is strongly involved in the NPD process, must be an integral part of the modeling approach. The repetitive use of simulation with representative sampling turns out to be the most efficient strategy.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523881

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10604-10614

Titre :	Meeting variable freshwater demand by flexible design and operation of the multistage flash desalination process
Type de document :	texte imprimé
Auteurs :	E. A. M. Hawaidi, Auteur ; I. M. Mujtaba, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10604-10614
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Desalination Design
Résumé :	In this work, the design and operation of multistage flash (MSF) desalination processes are optimized and controlled in order to meet variable demands of freshwater with changing seawater temperature throughout the day and throughout the year. On the basis of actual data, the neural network (NN) technique has been used to develop a correlation which can be used for calculating dynamic freshwater demand/consumption profiles at different times ofthe day and season. A storage tank is linked to the freshwater line of the MSF process which helps avoiding dynamic changes in operating conditions of the process. A steady state process model for the MSF process coupled with a dynamic model for the storage tank is developed which is incorporated into the optimization framework within gPROMS modeling software. For a given design (process configuration), the operation parameters are optimized at discrete time intervals (based on the storage tank level which is monitored dynamically and maintained within a feasible limit) while the total daily cost is minimized.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523880

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10567-10603

Titre :	A comparative theoretical and computational study on robust counterpart optimization : I. robust linear optimization and robust mixed integer linear optimization
Type de document :	texte imprimé
Auteurs :	Zukui Li, Auteur ; Ran Ding, Auteur ; Christodoulos A. Floudas, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10567-10603
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Optimization
Résumé :	Robust counterpart optimization techniques for linear optimization and mixed integer linear optimization problems are studied in this paper. Different uncertainty sets, including those studied in literature (Le., interval set; combined interval and ellipsoidal set; combined interval and polyhedral set) and new ones (i.e., adjustable box; pure ellipsoidal; pure polyhedral; combined interval, ellipsoidal, and polyhedral set) are studied in this work and their geometric relationship is discussed For uncertainty in the left-hand side, right-hand side, and objective function of the optimization problems, robust counterpart optimization formulations induced by those different uncertainly sets are derived. Numerical studies are performed to compare the solutions of the robust counterpart optimization models and applications in refinery production planning and batch process scheduling problem are presented.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523879

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10557-10566

Titre :	Performance assessment for a class of nonlinear systems
Type de document :	texte imprimé
Auteurs :	Zhi Zhang, Auteur ; Li-Sheng Hu, Auteur ; Xue-Lian Zhang, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10557-10566
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Non linear system
Résumé :	In this paper, a class of specified nonlinear systems are concerned. The nonlinear process model can be considered as a simplified Kolmogorov―Gabor polynomial model, which is motivated by considering the actuator nonlinearity and the process output nonlinearity. In terms of this nonlinear system, the analytical performance benchmark and the associated benchmark controller are established by minimizing the variance of the measurement output The existence conditions of feedback invariant are discussed. The calculation of performance index, based on correlation analysis, is proposed. To facilitate assessment, a filtering or whitening method is presented. The white noise sequence is estimated by dynamic principal component analysis (DPCA), based on the nonlinear autoregressive exogenous (NARX) model. The numerical examples are given to illustrate the effectiveness of the proposed assessment method.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523878

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10549-10556

Titre :	Selecting the optimum predistillation scheme for heavy crude oils
Type de document :	texte imprimé
Auteurs :	Yanhong Wang, Auteur ; Yanjie Hou, Auteur ; Hong Gao, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10549-10556
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Crude oil
Résumé :	The problem of designing a crude distillation unit (CDU) is not only a distillation design. It has the added complexity that the properties of crudes are different around the world, sometimes from heavy to light. In this work, we focused our attention on designing a predistillation scheme suitable for heavy crude oils by thermodynamic analysis. The exergy efficiencies and losses were analyzed to evaluate available schemes indicating that the two-preflash-drums case, with the highest exergy efficiencies, lowest exergy losses, and lowest furnace duty, is the best choice for heavy crude oils. In addition, the method of selecting the optimum process for energy saving may benefit the process optimization of other distillation units.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523877

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10533-10548

Titre :	Framework for integrated model-centric process support
Type de document :	texte imprimé
Auteurs :	D. Aragon, Auteur ; P. A. Rolandi, Auteur ; J. A. Romagnoli, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10533-10548
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Modeling
Résumé :	In spite of the abundance of development efforts in the area of modeling and simulation of chemical processes, current process modeling environments, PMEs, continue to have two important drawbacks. First, they have been designed for modeling experts; and second, they have not been designed to formulate real process engineering problems involving raw plant measurements and their inherent high volume of data. In response to these shortcomings, the theoretical framework for support of process systems for realistic formulation of engineering model-based problems (Rolandi, P. A.; Romagnoli, J. A. Integrated model-centric framework for support of manufacturing operations Part I: The framework. Comput. Chem. Eng. 2010, 34, 17―35) was reformulated. This innovative formulation allows for the incorporation of new mechanisms and novel algorithmic approaches for outlier detection and dynamic data reconciliation, allowing for the treatment of real world plant data. A practical system was devised in Visual Basic and gPROMS and tested by means of two case studies, namely, two continuous stirred-tank reactor (CSTR) in series and a distillation column, demonstrating the great flexibility of the developed system. The performance of the framework and the practical software application were evaluated with simulated data as well as real data, demonstrating the effectiveness ofthe proposed methodologies for outlier detection and dynamic data reconciliation, which displayed high efficiencies and superiority to their traditional counterparts, offline as well as online.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523876

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10525-10532

Titre :	Improved performance of poly(Vinylidene Fluoride) microfiltration membranes prepared by freeze and immersion precipitation coupling method
Type de document :	texte imprimé
Auteurs :	Su, Yanlei, Auteur ; Yangui Liang, Auteur ; Chunxia Mu, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10525-10532
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Immersion Membrane separation Microfiltration
Résumé :	Cellulose acetate (CA) was used as a hydrophilic additive to blend with poly(vinylidene fluoride) (PVDF) for preparing casting solutions. A novel freeze and immersion precipitation coupling method was developed to improve the performance of PVDF microporous membranes. X-ray photoelectron spectroscopy (XPS) analysis confirmed the enrichment of CA segments on the PVDF membrane surfaces. The level of CA surface segregation on PVDF membrane surfaces was dramatically influenced by the freezing time. The hypothesis ofsolid (frozen DMSO)—liquid—solid (precipitated polymer) phase separation was proposed to explain the CA surface enrichment phenomenon. The mechanical strength and antifouling property of the PVDF microfiltration membranes were simultaneously improved by the synergistic action of freeze and immersion precipitation coupling technique. The PVDF microfiltration membranes exhibited higher permeability and better antifouling property in bioseparation process than that fabricated by the individual freeze technique.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523875

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10516-10524

Titre :	MIL-53(Al) : an efficient adsorbent for the removal of nitrobenzene from aqueous solutions
Type de document :	texte imprimé
Auteurs :	Dinesh V. Patil, Auteur ; Phani B. Somayajulu Rallapalli, Auteur ; Ganga P. Dangi, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10516-10524
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Aqueous solution
Résumé :	MIL-53(Al), hydrothermally synthesized and purified by solvent extraction, was used as adsorbent for the removal of nitrobenzene from aqueous solution. Pristine MIL-53(Al) and MIL-53(Al) loaded with various amounts of nitrobenzene were characterized by X-ray diffraction analysis with cell indexation study, thermogravimetric analysis, Fourier transform infrared spectroscopy, and BET surface area. A simulation study of nitrobenzene adsorption on MIL-53(Al) was performed. The adsorption study of nitrobenzene on MIL-53(Al) was carried out at 30 ± 1 °C using batch experiments. The amount of nitrobenzene adsorbed decreases with an increase in the temperature from 30° to 60 °C and pH from 8 to 11, whereas no significant difference was observed in acidic pH. The adsorption data were fitted to Sips and Redlich―Peterson isotherm models. The adsorption capacity of nitrobenzene on MIL-53(Al) obtained was 610 mg/g, higher than that of zeolites (267.2 mg/g) and organoclays (100 mg/g), but, lower than that of modified commercial activated carbons (1443.53 mg/g).
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523874

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10509–10515

Titre :	Improved kinetic model of crystallization for isotactic polypropylene induced by supercritical CO2 : introducing pressure and temperature dependence into the avrami equation
Type de document :	texte imprimé
Auteurs :	Ren-Han Zhang, Auteur ; Xue-Kun Li, Auteur ; Gui-Ping Cao, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10509–10515
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Modeling Temperature effect Supercritical state Carbon dioxide Crystallization Kinetic model
Résumé :	Supercritical carbon dioxide (SC-CO2) provides a highly tunable technique to induce changes in morphology and crystallization kinetics of various polymers. In this study, the effect of SC-CO2 treatment on the crystallinity of isotactic polypropylene (i-PP) was analyzed by differential scanning calorimetry (DSC). The Avrami equation is suitable for describing crystallization kinetics ofvarious solids. However, the assumption that the crystallinity approaches 1.0 as the time approaches infinity is not valid for semicrystalline polymers, especially in the atmosphere of SC-CO2. An improved kinetic model for the CO2-induced crystallization of i-PP was purposed by introducing equilibrium crystallinity, as well as temperature- and pressure-dependent terms into the Avrami equation. The parameters of the crystallization kinetics model were obtained by least-squares fitting ofthe DSC data. The results show that the improved kinetic model provides a reasonable description of the crystallization behavior of i-PP induced by SC-CO2. The successful application of the improved kinetic model to the CO2-induced crystallization of i-PP suggests that this model may be adopted to other SC-CO2-semicrystalline polymer systems.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523873

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10500-10508

Titre :	Kinetics and mechanism of glucose decomposition in hot-compressed water : effect of initial glucose concentration
Type de document :	texte imprimé
Auteurs :	Yun Yu, Auteur ; Hongwei Wu, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10500-10508
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Kinetics
Résumé :	At a given reaction temperature (175―275 °C), the reaction rate constant of glucose decomposition in hot-compressed water (HCW) is found to decrease by almost 1 order of magnitude with increasing the initial glucose concentration from 0.01 to 1000 mg L―1 (equivalent to 5.6 x 10―8―0.0056 M). The results demonstrate a clear shift in the glucose decomposition mechanism at various initial glucose concentrations. Fructose is always the dominant reaction product with a high selectivity at the early stage of glucose decomposition, suggesting that it is a key primary product from glucose decomposition in HCW. The initial glucose concentration also influences the selectivity of glucose decomposition products substantially. The hydroxyl ion appears to play a controlling role in catalyzing the isomerization and retro-aldol reactions under all conditions in this study. At an initial glucose concentration less than 10 mg L―1 (i.e., 5.6 x 10―5 M), particularly when it is close to or less than the molar concentration of the ion product in HCW, the hydroxyl ions play a dominant role in catalyzing the isomerization and retro-aldol condensation reactions to produce fructose, glyceraldehydes and/or glycolaldehyde, erythrose, etc. However, at an initial glucose concentration higher than 10 mg L―1 (i.e., 5.6 x 10―5 M), the selectivity of 5-hydroxymethylfurfural increases substantially, indicating that hydrogen ions play an enhanced role in catalyzing dehydration reactions under the conditions. The shift in glucose decomposition mechanism is also reflected in the change in apparent activation energy that increases with an increasing initial glucose concentration, mainly due to an increasing selectivity of acid-catalyzed dehydration reaction that has a higher activation energy.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523872

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10493-10499

Titre :	Rate expression for water–gas shift over a gold/ferrochrome catalyst
Type de document :	texte imprimé
Auteurs :	Gaurav N. Vajani, Auteur ; Shea Lerk Ng, Auteur ; Carl R. F. Lund, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10493-10499
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Catalyst Water gas
Résumé :	The kinetics of low-temperature water―gas shift over gold/ferrochrome catalysts were studied at atmospheric pressure and temperatures between 160 and 180 °C. During two extended kinetic experiments lasting 903 and 1313 h, the activity of the catalyst decreased by 52% and 78%, respectively. The corresponding changes in the Brunauer-Emmett-Teller surface areas were 16% and 12%, respectively, suggesting that changes in the support surface area are not the primary cause for deactivation. The use of a bracketing technique, wherein the system was regularly returned to a standard set of reaction conditions, allowed the rate expression to be written as the product of an activity factor, which accounted for catalyst deactivation, and a power-law rate expression, which accounted for the dependence of the reaction rate upon temperature and composition. The power-law kinetic expression, including a term to account for the approach to equilibrium, was found to describe the kinetics of the reaction reasonably welL The resulting reaction orders were 0.39 for CO, 0.99 for H2O, -0.28 for CO2, and ―0.25 for H2, and the apparent activation energy was equal to 88.2 kJ/mol.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523871

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10480–10492

Titre :	Adsorption and reaction of NO2 on carbon black and diesel soot at near-ambient temperatures
Type de document :	texte imprimé
Auteurs :	Christopher. J. Tighe, Auteur ; Martyn V. Twigg, Auteur ; Allan N. Hayhurst, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10480–10492
Note générale :	Chimie indutsrielle
Langues :	Anglais (eng)
Mots-clés :	Soot Carbon black Adsorption
Résumé :	NO2 interacts with soot in the atmosphere and, at higher temperatures, is used as an oxidant to regenerate filters on the exhausts of diesel cars. This work investigates the adsorption and reaction of NO2 (forming NO) with either carbon black or soot (from a diesel engine) held at near ambient temperatures (20―75 °C) in a packed bed. It was found that initially NO2 very rapidly adsorbed; approximately half the NO2 adsorbed was converted to NO, leaving behind O-containing functionalities on the surface of the carbon. These adsorbed species can be made to produce CO2 and CO by heating the carbon to a temperature above 100 °C. At 20 °C, the number of O-containing species, C(O), formed on the carbons was found, surprisingly, to be equal to the amount of NO2 remaining stably adsorbed. A mechanism of elementary reactions is postulated, in which NO2 is only adsorbed on the newly formed C(O). A model of adsorption and reaction in a packed bed was used to estimate kinetic parameters for the surface reactions giving overall C(_) + 2NO2 → C(O + NO2) + NO. The measurements of [NO2] and [NO] against time were represented best by the reactions C(_) + NO2 → C(NO2), C(NO2) → C(O) + NO, and C(O) + NO2 → C(O + NO2); each is first order with respect to NO2. Excellent agreement between the results of modeling and experiment is obtained by assuming that there are two types of active site, C(_), with different reactivities.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523870

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10476–10479

Titre :	Gas-limited hydrogenation of 1-octene in a fixed bed : upflow versus downflow
Type de document :	texte imprimé
Auteurs :	F. Reynders, Auteur ; W. Nicol, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10476–10479
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Downward flow Upward flow Fixed bed Hydrogenation
Résumé :	Two downflow operational modes with different hydrodynamic states were compared to upflow operation. Various gas-limited conditions (γ = 15—60) were employed. The downflow mode with the higher wetting efficiency consistently outperformed the downflow mode with the lower wetting efficiency. Both downflow modes outperformed the upflow mode at high gas mass fluxes and underachieved against upflow at lower gas mass fluxes. The results stand in contradiction to the theory on direct gas-solid mass transfer under trickle-flow conditions. The switching behavior of the upflow mode performance was attributed to hydrodynamic regime shifts, hinting that the perceived "poor" performance of upflow reactors under gas limited conditions might be linked to slugging in laboratory-scale reactors.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523869

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10465-10475

Titre :	Kinetics of carbon dioxide absorption into aqueous amino acid salt : potassium salt of sarcosine solution
Type de document :	texte imprimé
Auteurs :	Ugochukwu E. Aronu, Auteur ; Ardi Hartono, Auteur ; Karl A. Hoff, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10465-10475
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Gas absorption Carbon dioxide Kinetics
Résumé :	The kinetics of CO2 absorption into an unloaded aqueous solution of the potassium salt of sarcosine (KSAR) was studied using a string-of-disks contactor for the concentration range of 1.0―4.0 kmol m―3 and temperatures of 25―62 °C. The zwitterion and termolecular mechanisms were reinterpreted to account for nonidealities in salt systems due to the effect of ionic strength through the introduction of an ionic factor, kion. Both models adequately represent the experimental data with no practical difference. The reaction rate constant for KSAR is high but comparable to values for amines. It increases considerably with temperature and concentration. The reaction order varies with KSAR concentration from 1.25 to 1.81, with an overall average value of 1.58. The experimentally derived kinetic model was combined with a thermodynamic model of aqueous KSAR from Aronu et al. (Chem. Eng. Sci. 2011, 66, 2191-2198) to predict the loading dependency of the overall mass-transfer coefficient, KG, determined in pilot-plant experiment. The predicted results show that the experimental data agree well with the pilot-plant results.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523868

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10458-10464

Titre :	A novel dual-membrane reactor for continuous heterogeneous oxidation catalysis
Type de document :	texte imprimé
Auteurs :	Hong Jiang, Auteur ; Lie Meng, Auteur ; Rizhi Chen, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10458-10464
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Catalysis Oxidation Membrane reactor
Résumé :	A novel dual-membrane reactor is proposed for heterogeneous catalysis over ultrafine catalyst particles. In this reactor, one tubular porous ceramic membrane is employed as a distributor controlling the supply of reactant, while the other is employed as a membrane separator for in situ separation of ultrafine catalysts from the products. To evaluate the feasibility and the performance of the dual-membrane reactor, phenol hydroxylation with hydrogen peroxide (H2O2) over TS-1 catalyst was selected as a model reaction. As compared to traditional H2O2 feeding modes, the use of the porous ceramic membrane distributor allows a uniform injection of H2O2 into the reaction system, and as a result significantly promotes the dihydroxybenzene selectivity. The phenol conversion and the DHB selectivity above 15% and about 95%, respectively, can be achieved in a continuous operation of 30 h. TS-1 catalysts can be retained almost completely in the reactor system by the membrane separator. Our study demonstrates the advantages of the novel dual-membrane reactor in enhancing selectivity and catalysts separation in a continuous heterogeneous catalytic reaction.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523867

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10452–10457

Titre :	Oxidative desulfurization II : temperature dependence of organosulfur compounds oxidation
Type de document :	texte imprimé
Auteurs :	Paolo De Filippis, Auteur ; Giuseppe Liuzzo, Auteur ; Marco Scarsella, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10452–10457
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Temperature effect Desulfurization Oxidation
Résumé :	In this work the oxidation of benzo-, dibenzo-, 4-methyldibenzo-, and 4,6-dimethyildibenzothiophene in the presence of hydrogen peroxide and formic acid was studied over the temperature range of 20―65 °C. The experimental data were interpreted by means of a interfacial mass transfer and reaction model developed in the first part of this study. The parameters identification tool available in gPROMS environment allowed a regression of the Arrhenius constants of the rate determining step characterizing the considered oxidation reactions. The activation energies of the thiophenes oxidation reactions result in 34.6 kJ/mol and 29 ± 1 kJ/mol for BT and DBTs, respectively.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523866

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10434-10451

Titre :	Effect of aviation fuel type on pyrolytic reactivity and deposition propensity under supercritical conditions
Type de document :	texte imprimé
Auteurs :	Matthew J. DeWitt, Auteur ; Tim Edwards, Auteur ; Linda Shafer, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10434-10451
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Supercritical state Chemical reactivity Fuel
Résumé :	Development of reusable liquid-hydrocarbon-fueled hypersonic vehicles requires improved understanding of the effect of chemical composition on the controlling reaction chemistry and deposition propensity as the fuel is used to cool the system. In this effort, supercritical pyrolytic stressing studies were performed using two petroleum-derived fuels and a Synthetic Paraffinic Kerosene (SPK) comprised predominantly of normal and branched paraffins. All fuels decomposed via free radical pathways with high yields of unsaturates and lower molecular weight products consistent with pyrolysis at high pressures and moderate temperatures. However, the SPK was significantly more reactive than the petroleum-derived fuels due to a lack of efficient hydrogen donors that act to terminate chain reactions (higher net propagation rate). High-pressure liquid chromatography was used to identify and quantify polycyclic aromatic hydrocarbons (PAH) in the stressed fuels, conclusively determining that these are produced during thermal stressing. A notable observation was the presence of PAH during SPK stressing, as the neat fuel did not contain cyclic precursors for growth to PAH. During stressing with stainless-steel tubing, the formation of filamentous deposits via metal-catalyzed reactions of stressed fuel components with reactor surfaces was observed for all fuels studied. However, the SPK fuel exhibited a much higher pyrolytic deposition rate, which was attributed to higher lateral growth rates of surface filaments via noncatalytic free radical addition pathways. The PAH formed during SPK stressing are indicators of the highly reactive intermediates prone to participating in the surface coke addition pathways. Studies blending benzene with the SPK indicated that low PAH solubility in the paraffinic fuel is not the dominant cause for the high deposition propensity. Testing with the petroleum-derived fuels showed that metal sulfide filament formation can occur under endothermic conditions, and higher fuel sulfur content can increase carbon deposition propensity. Studies with surface passivated tubing (Silcosteel) suppressed filamentous carbon formation and rendered a substantial reduction in SPK deposition to levels similar to the petroleum-derived fuels. Overall, these studies provided guidance regarding the controlling chemistry during supercritical pyrolysis of current and potential synthetic hydrocarbon fuels and insight into prevalent deposition pathways.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523865

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10424–10433

Titre :	Experimental study of biomass pyrolysis based on three major components : hemicellulose, cellulose, and lignin
Type de document :	texte imprimé
Auteurs :	Tingting Qu, Auteur ; Wanjun Guo, Auteur ; Laihong Shen, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10424–10433
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Biomass Pyrolysis Hemicellulose
Résumé :	Fast pyrolysis of cellulose, xylan, and lignin was experimentally conducted between 350 and 650 °C in a tube furnace, and the effect of temperature on pyrolysis products (char, noncondensable gas, and bio-oil) was investigated. The yields of char, noncondensable gas, and bio-oil were quantified using gas chromatography and gas chromatography with mass spectrometry. The noncondensable gas mainly consists of CO, CO2, CH4, and H2. The bio-oil includes acids, ketones, aldehydes, esters, benzenes, alcohols, alkenes, phenols, alkanels, carbohydrates, etc. The results show that cellulose is the principal source of carbohydrates and phenols are the basis of the bio-oil from lignin, while the bio-oil from xylan mainly consists of acids, ketones, aldehydes, and phenols. The char yields for the three components decrease with an increase in temperature, and the gas yields and bio-oil yields increase with an increase in temperature, reach a maximum at a certain temperature, and then decrease after that temperature. The maximum bio-oil yields for cellulose, xylan, and lignin are 65, 53, and 40%, respectively; and their corresponding temperatures are 400, 450, and 500 °C, respectively. To investigate a relationship between biomass and three major components (hemicellulose, cellulose, and lignin), the pyrolysis of three typical biomass samples (rice straw, corn stalk, and peanut vine) was also studied, and the additivity law is adopted to predict the product components of biomass pyrolysis based on the content of hemicelluloses, cellulose, and lignin. The results show that the additivity law can predict reasonably the trend of product yields of biomass samples from their composition of hemicelluloses, cellulose, and lignin.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie1025453

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10414-10423

Titre :	Blend microspheres of poly(3-hydroxybutyrate) and cellulose acetate phthalate for colon delivery of 5-fluorouracil
Type de document :	texte imprimé
Auteurs :	Kiran Chaturvedi, Auteur ; Anandrao R. Kulkarni, Auteur ; Tejraj M. Aminabhavi, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10414-10423
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Microsphere
Résumé :	Blend microspheres of poly(3-hydroxybutyrate) (PHB) and cellulose acetate phthalate (CAP) have been prepared in compositions of 2:1, 1:1, and 1:3 (w/w) by the solvent evaporation technique. These pH-sensitive polymers were utilized to investigate the colon delivery of 5-fluorouracil (5-FU), an anticancer drug. The surface morphology of the microspheres was studied by scanning electron microscopy (SEM), which confirmed their spherical nature with sizes ranging from 29 to 67 μm, as well as pore structures before and after the dissolution experiments. Fourier transform infrared (FTIR) spectroscopy was used to confirm the polymer blend compatibility and to confirm the absence of drug–polymer interactions. Differential scanning calorimetry (DSC) was employed to study the crystalline nature and molecular-level dispersion of 5-FU in the matrixes after encapsulation. In vitro release experiments were performed at 37 °C in simulated buffer medium of the stomach (pH 1.2) for 2 h, followed by simulated intestinal medium (pH 7.4). It was found that the release of 5-FU from blend microspheres followed pH-dependent release as compared to that of plain PHB microspheres. From the in vitro release studies, it was found that blend microspheres are more efficient at delivering 5-FU to the colon than plain PHB microspheres. Furthermore, release data were fitted to empirical equations to understand the nature of the drug release profiles.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523863

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10407–10413

Titre :	Calorimetric and microscopic studies on the noncatalytic hydrothermolysis of ammonia borane
Type de document :	texte imprimé
Auteurs :	Junshe Zhang, Auteur ; Yu Zhao, Auteur ; Daniel L. Akins, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10407–10413
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Calorimetric Microscopic Hydrothermolysis
Résumé :	The hydrothermolysis of ammonia borane (AB) can release more hydrogen than AB thermolysis itself at mild temperatures. To obtain more insight into the noncatalytic hydrothermolysis, we investigated this process using a high-pressure differential scanning calorimeter and characterized the condensed residue by thermal analysis and infrared spectroscopy. For mass ratios of AB to water of 3.6, 1.44, and 0.72, the first pyrolysis step is not completed in 1 h at 85 °C. As the temperature increases from 25 to 115 at 1 °C min–1, there exist two exothermic peaks for the mass ratio of 3.6, centered around 82 and 103 °C on the heat flow curve, attributed to the hydrolysis and the first step of AB pyrolysis, respectively. For the mass ratio of 1.44, the top temperatures of these two exothermic peaks are 90 and 100 °C, respectively. However, for the mass ratio of 0.72, only the exothermic peak related to hydrolysis is observed, and its top temperature is ca. 106 °C. At temperatures up to 115 °C, the structural features associated with the product of the second pyrolysis step are absent for the mass ratios of 1.44 and 3.6. In the noncatalytic hydrothermolysis, the hydrolysis occurs much faster than the pyrolysis, and the latter is accelerated by both the heat desorbed from the hydrolysis and its product. Our findings suggest that water prefers reacting with AB rather than binding to the hydrolysis product to form hydrates and the hydrolysis itself can generate about 9 wt % of hydrogen with respect to the total mass of AB and water if sufficient AB is present. In this case, the heat of hydrolysis is 131 kJ (mol of AB)−1, and the solid hydrolysis product decomposes at temperatures about 350 °C.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie200878u

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10400-10406

Titre :	Effect of demineralization on product yield and composition at isothermal pyrolysis of eynez lignites
Type de document :	texte imprimé
Auteurs :	Murat Sert, Auteur ; Levent Ballice, Auteur ; Mithat Yuksel, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10400-10406
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Pyrolysis
Résumé :	In this study, the effect of the mineral matter of Eynez lignite on the volatile hydrocarbon recovery, the yield of polycyclic aromatic hydrocarbons (asphaltenes, preasphaltenes), and the carbon in the solid residue was investigated. First, lignite was demineralized with HCl, HNO3, and HF, successively. Then, the samples obtained from the demineralization step were pyrolyzed in isothermal pyrolysis reactor. The reaction temperatures are 450, 500, 550, 600, and 650 °C. Pyrolysis products were analyzed in capillary gas chromatography, and product evolution rate was calculated. The results show that removal of the inorganic elements in HCl decreased the volatile hydrocarbon recovery and that HNO3 slightly affected the conversion of organic materials in the pyrolysis reactions. In contrast, removal of the inorganic elements in HF increased the conversion in pyrolysis reactions. This behavior is explained by the inhibitive effect of the silicate minerals.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523861

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10393–10399

Titre :	Inhibition of Ca3(PO4)2, CaCO3, and CaSO4 precipitation for industrial recycling water
Type de document :	texte imprimé
Auteurs :	Fu Change, Auteur ; Zhou Yuming, Auteur ; Liu Guangqing, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10393–10399
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Industrial recycling water
Résumé :	In an attempt to control Ca3(PO4)2, CaCO3, and CaSO4 deposits in industrial recycling water systems, an acrylic acid (AA)–allylpolyethoxy carboxylate (APEC) copolymer was examined as a nonphosphorus inhibitor. The synthesized AA–APEC copolymer was characterized by FT-IR. The performance of AA–APEC on inhibition of Ca3(PO4)2, CaCO3, and CaSO4 precipitation was compared with that of current commercial inhibitors. It was shown that AA–APEC exhibited excellent ability to control inorganic minerals, with approximately 82.88% CaSO4 inhibition and 99.89% Ca3(PO4)2 inhibition at levels of 3 and 6 mg/L AA–APEC, respectively. AA–APEC also displayed ability to prevent the formation of CaCO3 scales. Transmission electron microscopy (TEM) images indicated that the outstanding performance of AA–APEC on Ca3(PO4)2 inhibition resulted from a decrease in size of Ca3(PO4)2 solid particles thereby dispersing these particles throughout a fluid, while CaCO3 inhibition was attributed to the formation of ribbon-shaped structures and CaSO4 inhibition resulted from loose CaSO4 crystallites speculated on scanning electron microscopy (SEM) images. The proposed inhibition mechanism suggests the formation of complexes between the side-chain carboxyl groups of AA–APEC and calcium ions on the surface of inorganic minerals, and the excellent solubility of complexes resulted from a number of hydrophilic polyethylene glycol (PEG) segments.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie200051r

[article]
in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp. 10385–10392

Titre :	l - glutamic acid polymorph control using amino acid additives
Type de document :	texte imprimé
Auteurs :	Yuxin Mo, Auteur ; Leping Dang, Auteur ; Hongyuan Wei, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10385–10392
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Additive
Résumé :	Additive is an effective factor in controlling crystallization of polymorph. L-Tryptophan, L-leucine, L-threonine, L-histidine, L-alanine, and L-valine, as additives during L-glutamic acid crystallization, were investigated for probing their effects on the polymorphic transformation. L-Tryptophan was then chosen as a representative case to evaluate the effect of addition concentration on the morphology, nucleation, and polymorphic transformation rate of L-glutamic acid. It is shown that all these additives have a certain influence on the polymorphic transformation and the presence of a bulky side chain (phenyl) in L-tryptophan and L-histidine is identified as an essential feature in achieving stabilization of the α-polymorph. When the concentration of L-tryptophan reaches above 0.008 M, the elongation of crystals occur. Increasing L-tryptophan concentration, the transformation time and nucleation rate of L-glutamic acid are retarded. The inclusion behavior of additive molecules in L-Glu crystals was investigated, and the results show that the effect of additive molecule on the polymorphic transformation may be through incorporating into crystal structures by adsorption.
DEWEY :	660
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=24523859

Industrial & engineering chemistry research / Paul, Donald R. . Vol. 50 N° 18

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