Catalogue en ligne Bibliothèque Ecole Nationale Polytechnique d'Alger

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7860–7860

Titre :	Evaluation of the nonrandom hydrogen bonding (NRHB) theory and the simplified perturbed-chain-statistical associating fluid theory (sPC-SAFT). 2. liquid-liquid equilibria and prediction of monomer fraction in hydrogen bonding systems
Type de document :	texte imprimé
Auteurs :	Ioannis Tsivintzelis, Auteur ; Andreas Grenner, Auteur ; Ioannis G. Economou, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7860–7860
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Note de contenu :	Assition and corrections of article Evaluation of the nonrandom hydrogen bonding (NRHB) theory and the simplified perturbed-chain-statistical associating fluid theory (sPC-SAFT). 2. liquid-liquid equilibria and prediction of monomer fraction in hydrogen bonding systems Vol. 47 N° 15/ 2008
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901084h

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7852–7859

Titre :	Regression analysis for the two-step growth kinetics of crystals in pure solutions
Type de document :	texte imprimé
Auteurs :	K. Vasanth Kumar, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7852–7859
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Growth kinetics Crystals Pure solutions Mass transfer model
Résumé :	The overall growth kinetics of ammonium pentaborate, borax decahydrate, and boric acid crystals in pure solutions were analyzed using a two-step mass transfer model. Four different linear expressions of the two-step mass transfer model (TSM), which include the widely used expressions of Sobczak and Karpinski, were discussed. The influence of linearization for an assumed second-order reaction kinetics on the mass transfer and reaction steps was studied for various crystallization systems with overall growth kinetic order ranging from 1 to ≥2. The overall growth kinetics of ammonium pentaborate and borax decahydrate were used to study the effect of linearization as a function of temperature and seed size. The complexities in using the linearized TSM expression to predict the mechanism of the crystal growth process in pure solutions were discussed. A Type 3 expression of Karpinski that successfully represents the overall crystal growth kinetics was determined to be successful in representing two-step growth of borax decahydrate and ammonium pentaborate crystals. Type 1 and Type 4 expressions were determined to be inappropriate for the studied crystallization systems, because they either poorly fit the growth kinetics or produce kinetic parameters without physical meaning. The Sobczak expression well-represents the overall crystal growth kinetics of second order or more, and the Karpinski expression was determined to be successful in representing the overall crystal growth kinetics of order near or equal to unity.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9002975

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7847–7851

Titre :	Phase equilibria of hydrogen sulfide clathrate hydrates in the presence of methanol, ethanol, NaCl, KCl, or CaCl2 aqueous solutions
Type de document :	texte imprimé
Auteurs :	Amir H. Mohammadi, Auteur ; Richon, Dominique, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7847–7851
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Hydrogen sulfide clathrate hydrates Methanol aqueous solution Ethanol aqueous solution NaCl aqueous solution KCl aqueous solution CaCl2 aqueous solution
Résumé :	Equilibrium data for hydrogen sulfide clathrate hydrates in the presence of methanol, ethanol, NaCl, KCl, or CaCl2 aqueous solutions are reported in this work. The experimental data were generated using an isochoric pressure-search method. These data are compared with the literature data in the presence of pure water to identify the hydrate inhibition effects of the aforementioned aqueous solutions.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900821p

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7842–7846

Titre :	Approximate method for designing a primary settling tank for wastewater treatment
Type de document :	texte imprimé
Auteurs :	Gloria Martínez-González, Auteur ; Herbert Loría-Molina, Auteur ; David Taboada-López, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7842–7846
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Analogous Fick’s law mass transport model Wastewater treatment
Résumé :	An approximate method based on an analogous Fick’s law mass transport model was derived to predict the concentration profiles of suspended particles in a primary sedimentation tank for wastewater treatment as a function of time and column height. A pilot sedimentation column was constructed to test wastewater sedimentation and obtain the necessary data for the proposed model. The examined variables included the total suspended solids concentration, the sedimentation height, and the time elapsed. Computer code was developed to estimate the dispersion coefficient present in the sedimentation model from experimental data via least-squares regression, resulting in a relative error of 3.705%. The proposed model was validated by good agreement with reported data in the literature. The basic dimensions for designing a primary sedimentation tank were obtained based on the experimental data from wastewater samples obtained by a wastewater collector located in the industrial zone of Celaya City, México. This methodology can be successfully applied for designing primary sedimentation tanks for wastewater treatment facilities.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801869b

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7838–7841

Titre :	Phase equilibria of clathrate hydrates of tetrahydrofuran + hydrogen sulfide and tetrahydrofuran + methane
Type de document :	texte imprimé
Auteurs :	Amir H. Mohammadi, Auteur ; Richon, Dominique, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7838–7841
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Tetrahydrofuran + hydrogen sulfide Tetrahydrofuran + methane Clathrate hydrates
Résumé :	In this work, experimental dissociation data for the clathrate hydrates of tetrahydrofuran + hydrogen sulfide and tetrahydrofuran + methane are reported. The experimental data were generated using an isochoric pressure-search method. The dissociation data for the tetrahydrofuran + methane clathrate hydrates are compared with the corresponding experimental data reported in the literature, and the acceptable agreement demonstrates the reliability of the experimental method used in our work. Moreover, we extend the literature data for the latter system to a low concentration of tetrahydrofuran in its aqueous solution. As addition of high concentrations of tetrahydrofuran in aqueous solution diminishes its pressure-reducing effect, we therefore measured and report the experimental dissociation data for the tetrahydrofuran + hydrogen sulfide clathrate hydrates at low concentrations of tetrahydrofuran in its aqueous solution.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900774v

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7828–7837

Titre :	Application of a new lattice-fluid equation of state based on chemical-association theory for polymer systems
Type de document :	texte imprimé
Auteurs :	Xiaochun Xu, Auteur ; Changjun Peng, Auteur ; Guiping Cao, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7828–7837
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Lattice-fluid equation of state Fluid systems Ionic liquid systems
Résumé :	In our previous work, a new lattice-fluid equation of state (LF-EoS) was developed and successfully applied to normal fluid systems and ionic liquid systems. In this work, this LF-EoS is further extended to describe thermodynamic properties of polymer systems. First, the model parameters for polymers were determined by fitting experimental pVT data of polymers over a wide temperature and pressure range. Then, the LF-EoS was applied for calculating vapor−liquid equilibrium (VLE) of polymer−solvent systems using one adjustable binary parameter κ12. The solubility of gas in polymer can be calculated up to a high pressure. Moreover, a new parameter Cr was introduced to describe the effect of composition of mixtures on chain length parameter r, and several typical liquid−liquid equilibrium behaviors of polymer solutions can be successfully reproduced.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900676n

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7821–7827

Titre :	High-pressure phase behavior for poly[dodecyl methacrylate] + supercritical solvents + cosolvents and carbon dioxide + dodecyl methacrylate mixture
Type de document :	texte imprimé
Auteurs :	Liu Shuang, Auteur ; Ha-Yeon Lee, Auteur ; Soon-Do Yoon, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7821–7827
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Cloud-point curve Poly(dodecyl methacrylate) Dodecyl methacrylate Binary mixtures Ternary mixtures
Résumé :	Experimental cloud-point curves for poly(dodecyl methacrylate) [P(DDMA)] + dodecyl methacrylate (DDMA) or dimethyl ether (DME) in supercritical CO2 are reported for the binary and ternary mixtures up to 473 K and 248.0 MPa. The location of the P(DDMA) + CO2 cloud-point curve shifts to lower temperatures and pressures when DDMA or DME is used as a cosolvent. P(DDMA) does not dissolve in pure CO2 to the temperature of 493 K and the pressure of 260.0 MPa. High-pressure phase behavior data are presented for the CO2 + DDMA system at 313.2−393.2 K and up to ca. 25.2 MPa. The system exhibits type-I phase behavior with a continuous mixture-critical curve, and the system is adequately modeled with the Peng−Robinson equation of state. High-pressure phase behavior data are reported for P(DDMA) in supercritical propane, propylene, butane, and 1-butene. Cloud-point curves for the P(DDMA) in C4 hydrocarbons are at lower temperatures than the P(DDMA) + C3 hydrocarbons curves at fixed pressures.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900598w

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7813–7820

Titre :	Fluid dynamics analysis of a draft-tube continuous spouted bed with particles bottom feed using CFD
Type de document :	texte imprimé
Auteurs :	Cezar A. da Rosa, Auteur ; José T. Freire, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7813–7820
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Draft tube continuous spouted bed Bottom feed Computational fluid dynamics
Résumé :	In this work the fluid dynamics behavior of a draft tube continuous spouted bed with particle bottom feed was studied through experimental data of static pressure, fountain height, and fluid mass flow in the annulus, as well as using the computational fluid dynamics. Experiments using glass beads as solid phase were carried out in two different velocity inlet conditions, 20 and 22 m/s. The inlet solid mass flow rate was 0.087 kg/s for the first case and 0.097 kg/s for the second one. Static pressure measurements were done in axial and radial coordinates for the entire equipment. The fountain height and fluid mass flow in the annulus were also evaluated during experiments. The Eulerian−Eulerian multifluid modeling approach was applied to predict gas−solid flow behavior. The Gidaspow (1994) drag model and the granular kinetic theory derived by Lun et al. (1984) were adopted here. A commercially available program, FLUENT 6.3, was chosen to carry out computer simulations. CFD simulations were able to predict very well the static pressure profile, fountain height, and fluid mass flow in the annulus.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900547u

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7798–7812

Titre :	Simultaneous quadrature method of moments for the solution of population balance equations, using a differential algebraic equation framework
Type de document :	texte imprimé
Auteurs :	Jolius Gimbun, Auteur ; Zoltan K. Nagy, Auteur ; Chris D. Rielly, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7798–7812
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Quadrature method of moment Differential algebraic equation system
Résumé :	The quadrature method of moments (QMOM) is a recent technique of solving population balance equations for particle dynamics simulation. In this paper, an alternative solution for the QMOM is described and thoroughly tested, which is based on the formulation and simultaneous solution of a semi-explicit differential algebraic equation (DAE) system. The DAE system consists of the ordinary differential equations resulting from the application of the method of moments, as well as a system of nonlinear algebraic equations derived by applying the quadrature theory for the approximation of the moments. It is shown that the proposed approach provides an efficient procedure for evolving the quadrature abscissas and weights from the QMOM. The Jacobian matrix of the DAE system is provided analytically to make the solution more robust. The DAE-QMOM method is compared to the well-established method for solving QMOM based on the product difference (PD) algorithm. The numerical results are compared to the analytical solutions in the case of breakage, aggregation, growth, and nucleation mechanisms. Excellent agreements are found on the moment evolution predicted by both methods. However, the DAE-QMOM method is found to be more accurate and robust than the PD-QMOM in some cases. Additionally, the DAE-QMOM is also capable of providing the solution significantly faster than the PD-QMOM method.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900548s

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7788–7797

Titre :	Symmetric electrolyte nonrandom two-liquid activity coefficient model
Type de document :	texte imprimé
Auteurs :	Yuhua Song, Auteur ; Chau-Chyun Chen, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7788–7797
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Electrolyte nonrandom two-liquid model Reformulated NRTL expression Vapor-liquid equilibrium Liquid-liquid equilibrium Solid-liquid equilibria
Résumé :	The electrolyte nonrandom two-liquid (eNRTL) model is reformulated as a symmetric activity coefficient model with the reference states chosen to be pure liquids for solvents and pure fused salts for electrolytes. These reference states are consistently used in the local interaction term, represented by a reformulated NRTL expression, and the long-range interaction term, represented by an extended symmetric Pitzer−Debye−Hückel expression. Retaining the local electroneutrality and like-ion repulsion hypotheses, the new symmetric electrolyte NRTL model yields simpler activity coefficient expressions for both molecular and ionic species. The utility of the model is demonstrated with vapor−liquid equilibrium, liquid−liquid equilibrium, and solid−liquid equilibria of several mixed solvent electrolyte systems.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9004578

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7780–7787

Titre :	The charge batching planning problem in steelmaking process using lagrangian relaxation algorithm
Type de document :	texte imprimé
Auteurs :	Lixin Tang, Auteur ; Shujun Jiang, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7780–7787
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Charge batching planning problem Steelmaking processing Lagrangian relaxation methods
Résumé :	In this paper, we investigate the charge batching planning problem (CBP) arising from practical steelmaking production. The CBP transforms the primary order requirements into various production batches (charges) subject to the steelmaking processing constraints and composite batch conditions according to the similarity in steelgrade, dimension, physical property, and due-date of orders. On the basis of a practical steelmaking process, a novel mixed-integer programming model for the CBP is presented by considering above constraints and features here, and two kinds of Lagrangian relaxation (LR) methods are proposed to solve the CBP by using different relaxation methods. In the first LR method, the relaxed problem is separated into subproblems by relaxing assignment constraints which are solved optimally by dynamic programming. In the second method, variable splitting is presented by introducing identical copies of some subsets of the original variables. To guarantee the equivalence to the primal problem, a number of equality coupling constraints are added into the model which are relaxed during the course of the second Lagangian relaxation. The multipliers in all above LR methods are then iteratively updated along subgradient directions. Computational experiments have been carried out and the results show that both LR methods can produce satisfactory average duality gaps and the second LR method is little better than the first method.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801454k

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7773–7779

Titre :	Solubility and phase transitions of calcium sulfate in KCl solutions between 85 and 100 °C
Type de document :	texte imprimé
Auteurs :	Liuchun Yang, Auteur ; Baohong Guan, Auteur ; Zhongbiao Wu, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7773–7779
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Calcium sulfate KCl solution
Résumé :	The solubility(s) of the three phases of CaSO4, namely, CaSO4·2H2O (DH), CaSO4·0.5H2O (α-HH), and CaSO4 (AH II), in 0.0−18.0 wt % KCl solutions were systemically investigated at temperatures ranging from 85 to 100 °C. At fixed temperature, the solubility(s) of the three phases all change with KCl concentration and possess a maximum value. The relative magnitudes of the variance of solubility for AH and α-HH are larger than that for DH. This was considered to be correlated to the combined effects of the temperature and concentration of KCl solution on the activity coefficients and water activity. The phase transition behaviors of α-HH and DH are presented with possible intermediate phases, which can be well-explained by the solubility difference of the three forms of CaSO4 and the tendency of forming görgeyite (K2Ca5(SO4)6·H2O).
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900372j

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7767–7772

Titre :	Comparison of solid−liquid equilibrium data for the adsorption of propionic acid and tartaric acid from aqueous solution onto amberlite IRA-67
Type de document :	texte imprimé
Auteurs :	Hasan Uslu, Auteur ; Ismail Inci, Auteur ; Sahika Sena Bayazit, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7767–7772
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Adsorption parameters Amberlite IRA-67 adsorbent Propionic acid Tartaric acid
Résumé :	Investigation of adsorption parameters such as effect of initial acid concentration, effect of amount of adsorbent, effect of temperatures, effect of contact time, fitting data to isotherms, and kinetic models for propionic acid and tartaric acid by using Amberlite IRA-67 adsorbent was studied. The maximum adsorption efficiencies were found to be 97.18% and 84.46% for tartaric acid and propionic acid, respectively. The best fitted isotherm was determined to be Langmuir for tartaric acid. The Langmuir isotherm was better fitted than the Frundlich isotherm for both acids. Elovich model equation was applied for data of each acids. The kinetics of the adsorption for both acids was determined as pseudo-second-order model.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9005639

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7753–7766

Titre :	Design of a counter-current interfacial partitioning process for the separation of ampicillin and phenylglycine
Type de document :	texte imprimé
Auteurs :	Martijn A. Hoeben, Auteur ; Pim van Hee, Auteur ; Rob G. J. M. van der Lans, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7753–7766
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Phenylglycine crystals Ampicillin crystals Interfacial partitioning
Résumé :	The design of a separation process for mixtures of ampicillin and phenylglycine crystals by interfacial partitioning is treated. Interfacial partitioning is a novel technique where particles can be separated in a liquid two-phase system by selective partitioning between the liquid phases and a third particle-rich layer positioned at the interface. There are different mechanisms of separation with distinguishable equilibrium partition relations. Several short-cut design procedures for multistage counter-current fractionation of binary particle mixtures are presented. The design procedures relate to the different equilibrium partition relations and deal with the issue of flow selection. One of the procedures is applied for the design of a separation process for mixtures of phenylglycine and ampicillin crystals in water/n-dodecane two-phase systems. It is experimentally shown that multistage operation of the process can lead to a better separation than a single stage partition process. Besides, it is shown that the design can be complicated by irreversible effects in the partition behavior of the crystals. Additionally, results are presented of experiments with a semicontinuously operated partition unit, which indicate the possibility of a fully continuous operation of interfacial partitioning. A considerable degree of separation can be achieved provided that thorough contact between both liquid phases and the particles is maintained.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800680c

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7733–7752

Titre :	Nonclassical composition fronts in nonlinear chromatography : delta-shock
Type de document :	texte imprimé
Auteurs :	Mazzotti, Marco, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7733–7752
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Nonlinear chromatography Binary systems
Résumé :	The local equilibrium theory of chromatography is applied to study binary systems subject to the mixed generalized Langmuir isotherm, ni = Hici/(1 − K1c1 + K2c2) (i = 1, 2), where components 1 and 2 are anti-Langmuir-like and Langmuir-like, respectively. Riemann problems, where a stream of a given composition is fed to a column initially saturated at a different composition, are analyzed. Within the hyperbolic region of the hodograph plane close to the origin, it is shown that such Riemann problems admit not only classical solutions, consisting of constant states separated by simple wave and shock wave transitions, but also nonclassical solutions, namely including a continuous nonsimple wave transition and a delta-shock. The latter can be viewed as a traveling spike of growing strength superimposed to the discontinuity separating the initial and the feed states. Exact conditions for the occurrence of classical and nonclassical solutions are derived. Thus, this work adds two new types of composition fronts to the classical ones already known in nonlinear chromatography. In the case of the delta-shock, the most striking new transition, it is possible to derive exact relationships for its properties, including the slope of its image in the physical plane, i.e. the reciprocal of its propagation speed, dt/dz = {1/W}{1 + ν((H1K2[n2] − H2K1[n1])/(H1K2[c2] − H2K1[c2]))}, where the symbol [·] denotes the jump across the discontinuity of the quantity enclosed. These analytical expressions match the results obtained through numerical simulations. The physical legitimacy of the model considered in this work is demonstrated theoretically and is further supported by the experimental evidence of the existence of delta-shocks that has been recently provided [Mazzotti et al. J. Chromatogr., submitted].
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9001537

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7724–7732

Titre :	Comparison of recycle chromatography and simulated moving bed for pseudobinary separations
Type de document :	texte imprimé
Auteurs :	Ju Weon Lee, Auteur ; Phillip C. Wankat, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7724–7732
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Simulated moving bed (SMB) process Pseudobinary separation Binary separation
Résumé :	The simulated moving bed (SMB) process has been extensively used in industrial separations for binary and pseudobinary separations. The SMB has been reported to have higher productivity and requires less desorbent than batch chromatography; however, in pseudobinary separations these advantages are dependent on the difference of adsorption behaviors of the nontarget components. In this research, the performance of batch chromatography with a single recycle stream was compared to SMB processes for pseudobinary separations of ternary nucleosides, a model system with competitive Langmuir isotherms. To compare the performances of SMB and recycle batch chromatography, detailed dynamic simulations of each process were performed with optimized operating conditions. The desorbent to feed ratio, D/F, of recycle chromatography was at least 2 times smaller than that of a four-column SMB process for most retained solute separations. For one case of least retained solute separation (2′-deoxycytidine/2′-deoxythymidine/2′-deoxyadenosine), minimum D/F of the four-column SMB process is approximately 15 times larger than that of recycle chromatography. The maximum productivity of recycle chromatography is 1.5−2 times larger than that of the four-column SMB process. When eight columns are used in the four-zone SMB process (two columns per zone), the performance (productivity, D/F, and pressure drop) is improved compared to the four-column SMB. The eight-column SMB has higher maximum productivity, and at the same productivity, it also has lower D/F and lower pressure drop compared to recycle chromatography. However, the recycle chromatography system is simpler and has fewer columns.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900092y

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7713–7723

Titre :	Thermodynamic modeling and simulation of styrene−butadiene rubbers (SBR) solvent equilibrium staged processes
Type de document :	texte imprimé
Auteurs :	Gabriel Ovejero, Auteur ; M. Dolores Romero, Auteur ; Eduardo Díez, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7713–7723
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Styrene−butadiene rubbers processing Polymer−solvent thermodynamics
Résumé :	The main purpose of this paper is to describe the necessary steps to model the equilibrium based operations in styrene−butadiene rubbers (SBRs) processing. First of all, we include a brief introduction to polymer−solvent thermodynamics, so later on, we can discuss about the experimental techniques reported in literature for this kind of system, emphasizing those we have used in our work (intrinsic viscosity and inverse gas chromatography). General comments about the thermodynamic models used and experimental data treatment are also included. But, the development of an accurate simulation model which can predict the final purity of the polymer involves other thermodynamic studies, in order to determine the relative affinities of several additives with both polymer and solvent. Thus, the behavior of several polar modifiers, which are commonly employed in the synthesis process, is also reported. Experimental equilibrium data, evaluation of predictive methods, and simulation results are also reported for these additives, showing that the selection of a suitable thermodynamic model is essential for the reliability of the simulations performed.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9006497

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7705–7712

Titre :	Phase behavior modeling of alkyl amine + hydrocarbon and alkyl amine + alcohol systems using a group contribution associating equation of state
Type de document :	texte imprimé
Auteurs :	Francisco A. Sanchez, Auteur ; Amir H. Mohammadi, Auteur ; Alfonsina Andreatta, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7705–7712
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Alkyl amine + hydrocarbon systemAlkyl amine + alcohol system State namely GCA-EoS
Résumé :	In this work, a group contribution-associating equation of state namely GCA-EoS, is extended to model the phase behavior of alkyl amine + hydrocarbon and alkyl amine + alcohol systems while considering the association of functional groups. A generalized routine has been implemented to quantify the association effects through functional groups with associating sites. The predictions of the model are found in good agreement with experimental data reported in the literature. The model parameters were estimated in the temperature range 218−428 K and pressures up to 735 kPa.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie802004v

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7694–7704

Titre :	Separation of gas mixtures with FricDiff : a comparison between experimental data and simulations
Type de document :	texte imprimé
Auteurs :	Bianca Breure, Auteur ; Lodewijk Schoon, Auteur ; Elias A. J. F. Peters, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7694–7704
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Helium−argon mixtures FricDiff modul
Résumé :	This work describes the experimental procedure and presents experimental results on the separation of helium−argon mixtures in a FricDiff module. A FricDiff module consists of two compartments separated by a porous screen. The mixture to be separated flows through one compartment, the separating agent through the other. Experiments were performed at room temperature and a pressure of approximately 2 bar with nitrogen as the separating agent. In the experiments the pressure of the inlet feed mixture was changed such that convective flow through the porous barrier took place either from the feed mixture compartment to the separating agent compartment or vice versa. The experimental data were compared with a numerical model showing good agreement between mole fractions and molar flow rates. Deviations were observed when the inlet pressures of the feed mixture were compared. This may be attributed to an inaccurate pressure measurement in the experimental setup.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801738v

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7687–7693

Titre :	Liquid−liquid extraction in a rotating-spray column : removal of Cr(VI) by aliquat 336
Type de document :	texte imprimé
Auteurs :	D. Bonam, Auteur ; G. Bhattacharyya, Auteur ; Bhowal, A., Auteur
Année de publication :	2009
Article en page(s) :	pp. 7687–7693
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Liquid−liquid extraction Rotating-spray column Interfacial chemical reaction
Résumé :	The effect of centrifugal force on mass-transfer rates in liquid−liquid extraction was investigated experimentally in a rotating-spray column. Extraction with interfacial chemical reaction was studied in this contactor by countercurrent contact of a dilute aqueous solution of hexavalent chromium (pH 2) with an extractant—Aliquat 336 (quaternary ammonium salt)—dissolved in kerosene (dispersed phase). The overall volumetric mass-transfer coefficient, based on a continuous phase (assuming plug flow of the phases), was measured to be an order higher than that in a conventional spray column. A mathematical model was developed for this contactor, considering axial dispersion in the continuous phase and internal circulation within drops. Simulation results suggested that the variation of kca, relative to the flow rate of the aqueous phase, was not significant at a constant rotor speed and a constant flow rate of the organic phase.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900012k

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7682–7686

Titre :	Self-heat recuperation technology for energy saving in chemical processes
Type de document :	texte imprimé
Auteurs :	Yasuki Kansha, Auteur ; Naoki Tsuru, Auteur ; Kazuyoshi Sato, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7682–7686
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Self-heat recuperation technology Thermal processes
Résumé :	An innovative self-heat recuperation technology has been developed for heating and cooling thermal processes, in which not only latent heat but also sensible heat are circulated in a feed−effluent heat exchanger of the thermal process by compressing the effluent stream without any heat addition. Applying this technology to the thermal processes, the amount of energy required was determined using a commercial process simulation tool, PROII. The proposed self-heat recuperation technology, in which the heat of an effluent stream is recuperated and reused for feed stream heating by gas and/or vapor recompression, was found to drastically reduce the energy consumption.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9007419

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7662–7681

Titre :	Optimization of recovery processes for multiple economic and environmental objectives
Type de document :	texte imprimé
Auteurs :	Elaine Su-Qin Lee, Auteur ; G.P. Rangaiah, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7662–7681
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Sustainability-economic developmen Environmental stewardship Aggregation method
Résumé :	Of the three spheres of sustainability—economic development, environmental stewardship, and societal equity, only the first two are quantifiable based on process variables. While economic criteria such as profit before taxes, payback period, and net present worth are well established, environmental objectives are recent and there is no general consensus on aggregation methods for calculating environmental impact. Many contributing factors have been identified for environmental impacts: impact on humans, ecosystem—terrestrial and aquatic, and local/global temperatures—global warming and ozone depletion, as well as photochemical oxidation, acid rain, and eutrophication. However, reported studies have used one aggregate environmental index as the objective in process design besides one economic objective. Hence, feasibility and usefulness of process optimization for more than two economic and environmental objectives is studied. Two case studies: a VOC (volatile organic component) recovery system and a solvent recovery system are chosen and optimized for both economic and environmental objectives using the elitist nondominated sorting genetic algorithm. The contributing factors to the environmental impacts are optimized individually or grouped into a few indices where appropriate. The objectives chosen for each round of optimization is two, several, or more, with at least one economic and one environmental objective. As they are partially or totally conflicting, Pareto-optimal solutions are obtained. These elucidate the trade-offs present, and the decision maker would be better equipped in choosing the best solution. The net flow method is then used to identify the best Pareto-optimal solution, whereby the decision maker’s preference has to be declared. Pareto-optimal solutions and the best Pareto-optimal solution for the two case studies are presented and discussed. Insights gained from considering a number of environmental objectives for process optimization are highlighted.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie802006w

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7647–7661

Titre :	Automated targeting technique for single-impurity resource conservation networks. Part 2: single-pass and partitioning waste-interception systems
Type de document :	texte imprimé
Auteurs :	Denny Kok Sum Ng, Auteur ; Dominic Chwan Yee Foo, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7647–7661
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Resource conservation network Automated targeting technique Waste-interception systems
Résumé :	Part 1 of this pair of articles presents an automated targeting technique to identify minimum fresh resource flow rate/cost targets in a resource conservation network (RCN) with material reuse/recycle. After the potential for conservation through direct reuse/recycle is exhausted, fresh resource consumption can be further reduced by incorporating waste-interception (regeneration) processes. Hence, the proposed automated targeting technique in part 1 of this pair of articles is extended to determine the targets for RCNs with interception placement. The waste-interception systems are modeled as treatment processes with either fixed outlet concentrations or fixed impurity load removal ratios. The approach also distinguishes between single-pass and partitioning regenerators, which have different implications for RCNs. Literature examples and industrial cases are solved to illustrate the proposed approach.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900127r

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7637–7646

Titre :	Automated targeting technique for single-impurity resource conservation networks. Part 1: direct reuse/recycle
Type de document :	texte imprimé
Auteurs :	Denny Kok Sum Ng, Auteur ; Dominic Chwan Yee Foo, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7637–7646
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Automated targeting technique Single-impurity resource conservation network Targeting technique
Résumé :	This pair of articles presents an optimization-based, automated procedure to determine the minimum resource consumption/target(s) for a single-impurity resource conservation network (RCN). This optimization-based targeting technique provides the same benefits as conventional insight-based pinch analysis, in yielding various targets for an RCN prior to detailed design. In addition, flexibility in setting the objective function is the major advantage of the automated targeting approach over a conventional pinch analysis technique. The model formulation is linear, which ensures that a global optimum can be found if one exists. In part 1 of this pair of articles, the model for direct material reuse/recycle is presented. Its application is then demonstrated for single, multiple, and impure external resources using several literature examples. Part 2 of this pair of articles extends the automated targeting technique for RCNs with waste-interception (regeneration) placement.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900120y

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7631–7636

Titre :	An algorithm for stabilizing unstable steady states for jacketed nonisothermal continually stirred tank reactors
Type de document :	texte imprimé
Auteurs :	Farouq S. Mjalli, Auteur ; N. S. Jayakumar, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7631–7636
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Continually stirred tank reactors Steady states Cooling jacket
Résumé :	The operation of nonisothermal jacketed continually stirred tank reactors (CSTRs) involves a high degree of nonlinearity, and for certain operating conditions this nonlinearity may cause concentration multiplicity at steady state. At these conditions, certain steady states will be unstable and difficult to observe and maintain. The dynamics of the cooling jacket has a profound effect on these conditions and hence should be taken into consideration for the proper reactor design. A novel steady-state design algorithm is presented here to stabilize the CSTR at such conditions. This is achieved by replacing the single CSTR by a cascade of reactors that are capable of stabilizing and maintaining the unstable steady state. The new design approach implements an optimization of the reactors operating parameters to achieve this solution. The implementation of the solution algorithm is shown graphically and also shown is the use of numerical computational optimization solution techniques. For a first order reaction, both solutions were successful at achieving the unstable steady state; however, the numerical solution was more accurate. Simulations of the new design showed that the reactors’ cascades were capable of stabilizing the metastable temperature to a high degree of accuracy.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900072g

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7624–7630

Titre :	Effect of geometry of the plenum chamber on gas distribution in a fluidized bed
Type de document :	texte imprimé
Auteurs :	Ali Mohammadkhah, Auteur ; Navid Mostoufi, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7624–7630
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Fluidized bed Plenum chambersComputational fluid dynamics technique
Résumé :	The computational fluid dynamics (CFD) technique was used to simulate a fluidized bed with eight different plenum chambers of different design. The effect of the geometry of the plenum chamber on the velocity profile on the distributor and the pressure drop across the distributor was investigated. The plenums were selected such that the influence of characteristics such as body shape, direction and location of gas entrance, entrance type, and existence and shape of the internal baffle could be studied. The results indicate that the geometry of the body and the existence of the baffle are the most important characteristics that affect the flow uniformity above the distributor. It was shown that the shape of the baffle does not have a remarkable impact on the velocity profile. The direction and location of the gas entrance each has a significant effect on the distribution quality. The downward injection of gas and placement of the gas entrance far enough from the distributor increases the uniformity of flow over the distributor. It was shown that the geometry of the plenum chamber affects the total pressure drop across the distributor. A correction factor was introduced to quantify the effect of the geometry of the plenum on the pressure drop of the perforated plate distributor.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9001684

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7616–7623

Titre :	Platinum-doped TiO2/Magnetic poly(methyl methacrylate) microspheres as a novel photocatalyst
Type de document :	texte imprimé
Auteurs :	Yi-Hung Chen, Auteur ; Matthias Franzreb, Auteur ; Rong-Hsien Lin, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7616–7623
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Pt-TiO2/mPMMA microspheresPhotocatalyst Polymerization process Titania-coating Pt-doping
Résumé :	The study focuses on the characterization of platinum-doped titanium dioxide-coated magnetic poly(methyl methacrylate) (Pt-TiO2/mPMMA) microspheres as a novel photocatalyst. The Pt-TiO2/mPMMA microspheres were prepared by a modified suspension polymerization process, followed by titania-coating and Pt-doping. The Pt-TiO2/mPMMA microspheres were synthesized with various Pt-doping levels in the range of 0.6−1.5 wt % TiO2 for comparison. The morphology, composition, Pt-doping content, and magnetic properties of the Pt-TiO2/mPMMA microspheres were characterized using scanning electron microscopy, transmission electron microscopy, energy dispersive spectrometry, X-ray diffraction, X-ray photoelectron spectroscopy, and superconducting quantum interference device. As a result, the superparamagnetic Pt-TiO2/mPMMA microspheres were successfully synthesized with particle sizes of 5−11 μm. The magnetite and TiO2 contents of the Pt-TiO2/mPMMA microspheres were estimated as 7.69 and 16.7 wt %, respectively, while the corresponding saturation magnetization was measured as about 4.39 emu/g. Furthermore, the doped Pt nanoparticles in the metallic state were found to have a particle density of (27.5−33.5) × 108 cm−2 on the surface of the Pt-TiO2/mPMMA microspheres. This density was found to increase with the synthesized Pt-doping concentration. The photocatalytic activity of the Pt-TiO2/mPMMA microspheres was further examined using the photodegradation of dimethyl phthalate in an aqueous solution. Dimethyl phthalate as one of the most common phthalic acid esters has been frequently detected in wastewater effluents and river water. Furthermore, the concentration of total organic carbons was monitored as an index of mineralization. A distinct photocatalytic efficiency improvement was shown with the employment of the Pt-TiO2/mPMMA microspheres as compared to the TiO2/mPMMA microspheres or direct photolysis.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900509t

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7603–7615

Titre :	Classical nucleation theory applied to homogeneous bubble nucleation in the continuous microcellular foaming of the polystyrene−CO2 system
Type de document :	texte imprimé
Auteurs :	Shunahshep Shukla, Auteur ; Kurt W. Koelling, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7603–7615
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Polymer−physical foaming agent solution Bubble nucleation Hydrodynamic constraints
Résumé :	In the continuous production of microcellular thermoplastic foam, a polymer−physical foaming agent (PFA) solution is subjected to a rapid pressure drop through an extrusion foaming die. Simulations were run for the flow of a polymer−PFA solution through an extrusion foaming die with an abrupt axisymmetric contraction. The pressure drops across the die obtained through the simulations showed good qualitative agreement with experimental pressure drop measurements on the foaming extrusion die obtained in our laboratory. Field values of pressure, temperature, and velocity were obtained at each point in the foaming die. Once the values of pressure and temperature were obtained along each point in the foaming die, classical nucleation theory for bubble nucleation was invoked to predict the local bubble nucleation rate downstream of the saturation surface. The hydrodynamic constraints to the nucleation rate were calculated by using a modified form of the classical nucleation theory that accounted for the diffusional and viscosity constraints to the rate of homogeneous nucleation. The capillarity approximation was found not to be valid for bubble nucleation of CO2 in polymers; a correction accounting for the curvature dependence of surface tension was applied to get nonzero nucleation rates for the system to reconcile theoretically predicted rates with experimental observations.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8011243

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7594–7602

Titre :	Properties of poly(lactic acid)/poly(butylene adipate-co-terephthalate)/nanoparticle ternary composites
Type de document :	texte imprimé
Auteurs :	Jiang, Long, Auteur ; Bo Liu, Auteur ; Jinwen Zhang, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7594–7602
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Poly(lactic acid) Flexible poly(butylene adipate-co-terephthalate) Ternary composites
Résumé :	Poly(lactic acid) (PLA) can be toughened by flexible poly(butylene adipate-co-terephthalate) (PBAT) at the cost of a certain degree of strength and modulus loss. In an attempt to achieve balanced overall properties, PLA ternary composites containing both PBAT and rigid nanoparticles, i.e., montmorillonite clay (MMT) or nanosized precipitated calcium carbonate (NPCC), were prepared by twin screw extrusion and subsequent injection molding. Mechanical testing demonstrated that the composites containing MMT exhibited higher tensile strength and modulus but lower elongation compared to the composites containing NPCC. Using maleic anhydride (MA) grafted PLA as a compatibilizer, the elongation of the ternary composites was substantially increased, possibly due to improved dispersion of the nanoparticles. The injection molded ternary composites were shown to have a skin−core layered structure. The skin and core layers were found to possess different microstructure, thermal behavior, and mechanical properties. The microstructure difference led to a sequential fracture behavior during tension testing: the fracture of the core layer was followed by the skin layer. The skin layer, with a higher degree of PLA chain alignment and conformational ordering than the core layer, exhibited a higher glass transition temperature, lower cold crystallization temperature, and a higher degree of perfection in crystalline structures.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900576f

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7581–7593

Titre :	Controlling particle size of a poorly water-soluble drug using ultrasound and stabilizers in antisolvent precipitation
Type de document :	texte imprimé
Auteurs :	Sameer V. Dalvi, Auteur ; Rajesh N. Dave, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7581–7593
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Liquid antisolvent precipitation process Poorly water-soluble drug Active pharmaceutical ingredients Ultrasoun
Résumé :	The objective of this work was to develop a better understanding of a potentially scalable, liquid antisolvent (LAS) precipitation process, for the preparation of stable aqueous suspensions of ultrafine particles of poorly water-soluble active pharmaceutical ingredients (APIs). A novel combination of jets, ultrasound, polymers, and surfactants was used for the precipitation and stabilization of ultrafine particles of griseofulvin (GF). Use of ultrasound and high stream velocities enhances micromixing, whereas addition of polymers/surfactants inhibits/lowers the particle growth. A combination of ultrasound, high jet velocities, and stabilizers decreased the GF particle size to 1.04 μm (±0.46 μm) from 30.8 μm (±14.2 μm), when none of the treatments were used. A rational understanding was developed for predicting process performance and selecting suitable particle growth inhibitors/stabilizers. Favorable process conditions and combinations of polymer and surfactants were also identified experimentally for the precipitation of ultrafine particles of GF with a narrow particle size distribution (PSD).
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900248f

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7574–7580

Titre :	Synthesis of barium sulfate nanoparticles using a spinning disk reactor : effects of supersaturation, disk rotation speed, free ion ratio, and disk diameter
Type de document :	texte imprimé
Auteurs :	Asghar Molaei Dehkordi, Auteur ; Alireza Vafaeimanesh, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7574–7580
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Barium sulfate nanoparticles Spinning disk reactor Free ion ratio
Résumé :	The aim of this research was to synthesize barium sulfate nanoparticles using a spinning disk reactor. Barium sulfate was produced by continuously pumping two aqueous solutions of BaCl2 and Na2SO4, respectively, into the chamber of spinning disk reactor, where a liquid−liquid reaction took place to form BaSO4. The influences of various operating and design parameters such as the initial supersaturation, disk rotation speed, free ion ratio, and the disk diameter on the size of barium sulfate nanoparticles were carefully investigated. By varying the supersaturation and disk rotation speed, a broad range of particle size ranging from micrometer sizes down to nanoparticles smaller than 100 nm can be produced. Using high disk rotation speed and high initial supersaturation, crystals ∼38 nm in size were produced. It was found that the variation of free ion ratio has a significant influence on the obtained particle size. Moreover, at a constant supersaturation and disk rotation speed, precipitation experiments with the excess amount of barium or sulfate ions lead to smaller mean particle size compared to those prepared under stoichiometric conditions.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801799v

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7567–7573

Titre :	Optimal control of the sintering strain rate of yttria-stabilized zirconia electrolytes for solid oxide fuel cells using a thermal-mechanical analyzer during the sintering process
Type de document :	texte imprimé
Auteurs :	Leo Chau-Kuang Liau, Auteur ; Rung-Kang Wu, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7567–7573
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Sintering process model Three-dimensional yttria-stabilized zirconia tapes Thermal−mechanical analyzer
Résumé :	The optimal sintering trajectories of three-dimensional (3D) yttria-stabilized zirconia (YSZ) tapes were prepared using a dynamic optimization method under the controlled sintering strain. The sintering process model was carried out by the combination of both the heat transport equation and the dynamic equation of the sintering strain rate, constructed by thermal−mechanical analyzer (TMA) data. The heating pathway of a constrained strain rate case was determined numerically and was further experimentally carried out by the TMA test. Results show that the distribution of the strain rate in the ceramic tape was influenced by the sample size and heating conditions. The optimally sintered YSZ electrolyte showed better electronic performance than those with constant heating rates based on the conductivity tests. Therefore, the formation of the strain rate can be one of the factors that influenced the quality of the YSZ electrolyte in the sintering process.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801435e

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7561–7566

Titre :	Oxidative dehydrogenation of ethane to ethylene with CO2 over Fe-Cr/ZrO2 catalysts
Type de document :	texte imprimé
Auteurs :	Shuang Deng, Auteur ; Songgeng Li, Auteur ; Huiquan Li, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7561–7566
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Fe−Cr/ZrO2 catalysts Thermogravimetric analysis Ethylene Ethane Dehydrogenation
Résumé :	The catalytic performance of Fe−Cr/ZrO2 catalysts, prepared by two different methods—coprecipitation and coprecipitation−impregnation were examined in oxidative dehydrogenation of ethane to ethylene using CO2 as an oxidant. Thermogravimetric analysis and physicochemical characterization such as XPS, XRD, and BET were performed to explore the correlation of catalytic performance with physicochemical properties of the catalysts. Catalytic tests show that Fe−Cr/ZrO2 catalysts prepared by coprecipitation−impregnation have higher catalytic stability, higher CO2 conversion, and lower ethylene selectivity in comparison to Fe−Cr/ZrO2 prepared by coprecipitation. The characterization results indicate that the dehydrogenation of ethane is activated by Cr3+ species and Fe3O4 is formed during the reaction, which can promote the reverse WGS reaction. Coke deposition is the main reason of the deactivation of the catalysts. A possible reaction mechanism was proposed on the basis of these results.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9007387

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7550–7560

Titre :	Mechanistic investigation of uncatalyzed and osmium(VIII) catalyzed oxidation of guanidine by Ag(III) periodate complex in aqueous alkaline medium : a comparative kinetic approach
Type de document :	texte imprimé
Auteurs :	Jyothi C. Abbar, Auteur ; Shekappa D. Lamani, Auteur ; Sharanappa T. Nandibewoor, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7550–7560
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Guanidine hydrochlorid Diperiodatoargentate(III) Catalyzed oxidation
Résumé :	The oxidation of guanidine hydrochloride (GH) by diperiodatoargentate(III) (DPA) has been investigated both in the absence and presence of [Os(VIII)] catalyst in alkaline medium at a constant ionic strength of 0.10 mol dm−3 spectrophotometrically. The oxidation products were identified by spectral studies. The stiochiometry was same in both the cases, i.e., [GH]/[DPA] = 1:1. In both the catalyzed and uncatalyzed cases, the order of the reaction with respect to [DPA] was unity while the order with respect to [GH] was <1 over the concentration range studied. The rate increased with an increase in [OH−] and decreased with an increase in [IO4−]. The order with respect to [Os(VIII)] was unity. Suitable mechanisms were proposed. The reaction constants involved in the different steps of the reaction mechanisms were calculated for both reactions. Kinetic experiments suggest that [Ag(H2IO6)(H2O)2] is the reactive silver(III) species and [OsO4(OH)2]2− is the reactive Os(VIII) species.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900691z

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7540–7549

Titre :	Optimization of mechanical agitation and evaluation of the mass-transfer resistance in the oil transesterification reaction for biodiesel production
Type de document :	texte imprimé
Auteurs :	Dario Frascari, Auteur ; Michele Zuccaro, Auteur ; Alessandro Paglianti, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7540–7549
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Sunflower oil KOH-catalyzed transesterification Mechanical agitation Biodiesel synthesis reaction
Résumé :	The KOH-catalyzed transesterification of sunflower oil with methanol was studied in batch conditions in a 22 L stirred reactor in order to (i) develop criteria for the energetic optimization of mechanical agitation in the biodiesel synthesis reaction; (ii) obtain preliminary information on the decantation of the reaction products; (iii) evaluate the influence of the mass-transfer resistance under different mixing conditions. Different combinations of radial, axial, and pitched-blade impellers were tested. For each combination an optimal rotational speed was identified, characterized on the one hand by a drastic reduction of the specific mixing energy, and on the other by a 20−30% increase of reaction time. An evaluation of the reaction and mass-transfer characteristic times showed that the optimized tests are characterized by a not negligible mass-transfer resistance. The complete halt of the agitation after a 1−2 min mixing time led to a further decrease of mixing energy, without any increase of reaction time. Preliminary decantation tests showed that the individuation of an optimized agitation speed for the reaction step, combined with the agitation halt after a short mixing time, has positive effects on the liquid−liquid separation step. The results were compared with those of a twin study conducted with static mixing.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900283j

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7529–7539

Titre :	Multiobjective optimization of industrial autothermal reformer for syngas production using nonsorting genetic algorithm II
Type de document :	texte imprimé
Auteurs :	Alireza Behroozsarand, Auteur ; Hadi Ebrahimi, Auteur ; Akbar Zamaniyan, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7529–7539
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Noncatalytic partial oxidation Catalytic steam reformer Syngas production
Résumé :	The multiobjective optimization of an industrial autothermal reformer consisting of a noncatalytic partial oxidation (POX) chamber and a two-section catalytic steam reformer was studied in order to produce syngas with H2/CO ratio near 1 for application in Fischer−Tropsch and oxo processes. Both thermodynamic modeling of the POX section and mathematical modeling of fixed beds were used for the optimization of the process for maximizing of methane conversion and CO selectivity and minimizing of CO2 makeup flow. The nonsorting genetic algorithm II was employed for the optimization problem. The adjustable parameters are feed temperature, O2/CH4 ratio, steam to methane (S/C) ratio, and the first and second catalytic bed lengths of the reforming part. The optimized case proposes a syngas product with H2/CO of 1 by a feed including O2/CH4 and S/C of 0.59 and 2.012, respectively. The optimized lengths of two catalytic beds are 1.79 m for the first bed and 5.51 m for the second.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900259n

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7517–7528

Titre :	High surface area vanadium phosphate catalysts for n-butane oxidation
Type de document :	texte imprimé
Auteurs :	Ali Asghar Rownaghi, Auteur ; Yun Hin Taufiq-Yap, Auteur ; Fateme Rezaei, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7517–7528
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Vanadium phosphorus oxide N-butane Oxidation
Résumé :	Vanadium phosphorus oxide (VPO) was prepared using the precipitation procedure and tested for potential use in the partial oxidation reaction of n-butane to maleic anhydride. In particular, the effect of reducing agents such as the isobutanol, 1-butanol, and glycol, subsequent water treatment, and microwave heating were investigated in detail. The optimum synthesis conditions were identified with respect to catalyst activity for the oxidation of n-butane. The activity and selectivity of VPO prepared catalysts have been evaluated in a fixed bed microreactor and in situ gas chromatography (GC) was used to evaluate the system efficiency and analyze the product effluent stream. The different catalysts exhibited a range of activities and selectivities under the same reaction conditions. The range in catalyst performance may be attributed to the crystal size as well as particle size of catalyst. The results were interpreted in terms of surface area and catalyst nanostructure, and it has been generally concluded that the catalyst surface area is enhanced by the employment of glycol as the reducing agent, followed refluxing by distilled water and drying by microwave irradiation. The catalyst produced using this method is the most active and selective catalyst for partial oxidation of n-butane to maleic anhydride. The catalyst lifetime was tested under the optimum reaction conditions, and the catalyst was found to be highly stable for more than 70 h. The characterization of both precursors and calcined catalysts was carried out using X-ray diffraction (XRD), inductively coupled plasma-atomic emission spectrometer (ICP-AES), Brunauer−Emmer−Teller (BET) surface area measurement, temperature programmed reduction (H2-TPR), and scanning electron microscopy (SEM).
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900238a

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7505–7516

Titre :	Catalytic conversion of thiophene under mild conditions over a ZSM-5 catalyst : a kinetic model
Type de document :	texte imprimé
Auteurs :	Lisette Jaimes, Auteur ; Hugo De Lasa, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7505–7516
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	FCC gasoline processes H-ZSM-5 zeolite Thiophene
Résumé :	Currently, refiners consider the post-treatment of FCC gasoline processes to be a viable and likely less costly path for meeting environmental regulations on sulfur. Several promising catalytic desulfurization post-treatment processes do not require hydrogen addition and use zeolites. This type of desulfurization leads to significant levels of coke, and as a result, it is being considered for implementation in twin fluid beds (reactor and regenerator) to maintain the catalyst activity. This study evaluates the conversion of thiophene on H-ZSM-5 zeolite in a silica matrix. Experiments were carried out in the CREC fluidized riser simulator under mild conditions using thiophene/n-octane and thiophene/1-octene mixtures. The results show a high and selective thiophene conversion. It is speculated that thiophene conversion takes place via ring opening and alkylation to form H2S, aromatics, alkylthiophenes, benzothiophene, and coke. These observations are in agreement with previous thermodynamic analyses. On this basis, a reaction network and kinetic model are proposed. Numerical regression leads to kinetic parameters with narrow spans, suggesting that the proposed model satisfactorily simulate thiophene removal under the suggested gasoline post-treatment conditions.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8020126

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7498–7504

Titre :	Syngas production via CO2 reforming of methane over Sm2O3-La2O3-supported Ni catalyst
Type de document :	texte imprimé
Auteurs :	W. D. Zhang, Auteur ; B. S. Liu, Auteur ; Y. P. Zhan, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7498–7504
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	CO2 reforming Syngas production Catalytic activity
Résumé :	CO2 reforming of methane into syngas over Sm2O3−La2O3 (SL)-supported Ni catalyst was investigated in a fixed-bed quartz reactor and the best catalytic activity was observed over Ni/SL (sol−gel) due to the reduction of the perovskite LaNiO3 and spinel La2NiO4 to form small nickel particles. The conversion of CH4 and CO2 over Ni/SL(sol−gel) were 55% and 57%, respectively, the selectivity of H2 and CO were 96% and 98%, significantly higher than those over Ni/SL (imp) catalyst at 700 °C and a GHSV of 4.8 × 104 mL·h−1·g−1cat. In the meantime, the Sm2O3−La2O3-supported Ni catalysts were characterized by means of techniques, such as BET, XRD, H2-TPR, TG/DTA, HRTEM, XPS, and XAES.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9001298

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7489–7497

Titre :	Synthesis, structure, and photocatalytic activity in orthorhombic perovskites LnVO3 and Ln1−xTixVO3 (Ln = Ce, Pr, and Nd)
Type de document :	texte imprimé
Auteurs :	Dipankar Saha, Auteur ; Sudarshan Mahapatra, Auteur ; T. N. Guru Row, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7489–7497
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	LnVO3 Ln1−xTixVO3 (Ln = Ce, Pr, and Nd) Solid state method Fourier analysis
Résumé :	Orthorhombic perovskite type LnVO3 and Ln1−xTixVO3 (Ln = Ce, Pr, and Nd) have been synthesized by the solid state method. The structures of these compounds have been unequivocally established based on high resolution powder X-ray diffraction data using Rietveld refinement methodology followed by difference Fourier analysis. It is shown that substitution of Ti occurs at the vanadium site and not at the cerium site. The compounds have been tested for photocatalytic degradation of various dyes and substituted phenols. It is observed that doping of Ti remarkably improves the photodegradation efficiency of these orthorhombic perovskites.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9006134

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7482–7488

Titre :	Production of sebacic acid using two-phase bipolar membrane electrodialysis
Type de document :	texte imprimé
Auteurs :	Fang Zhang, Auteur ; Chuanhui Huang, Auteur ; Tongwen Xu, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7482–7488
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Sebacic acid Two-phase bipolar membrane electrodialysis
Résumé :	To produce a water-insoluble acid—sebacic acid—in an environmentally friendly manner, two-phase bipolar membrane electrodialysis (TPBMED) was proposed to convert sodium sebacate into sebacic acid in ethanol−water mixtures. The results indicated that BP-C configuration (BP, bipolar membrane; C, cation-exchange membrane) was better than the other configurations: BP-A (A, anion-exchange membrane), BP-A-C, and BP-A-A. In a TPBMED stack of BP-C configuration, the sodium sebacate could be totally transformed to sebacic acid with a current efficiency of 94% and energy consumption of 2.2 kW h kg−1. The process cost was estimated to be $0.57 kg−1. Nonetheless, to simultaneously dissolve sebacic sodium and sebacic acid, the ethanol content in the mixture was controlled at 60 v/v %, and the maximal concentration of sebacic acid produced was only 0.13 mol dm−3 due to the limit on solubility.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900485k

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7474–7481

Titre :	Porosity development in activated carbons prepared from walnut shells by carbon dioxide or steam activation
Type de document :	texte imprimé
Auteurs :	Juan F. González, Auteur ; Silvia Román, Auteur ; Carmen M. González-García, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7474–7481
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Activated carbons Porosity development Walnut shells
Résumé :	The influence of carbon dioxide and steam as activating agents on the porosity development of activated carbons produced from walnut shells was investigated. The study was made covering a wide range of burnoff (12−76%) and employing different temperatures and times: in carbon dioxide activation, 850 °C varying the activation time in the range 60−480 min, and in steam activation, 700, 850, and 900 °C (for 30−120 min). It was found that the gasifying agent has a profound influence on the activated carbon porosity development. First, steam is more reactive and produces, in general, activated carbons with greater N2 adsorption capacity. Second, the increase in the fraction of mesopores with activation time is more pronounced for steam. While steam generates micro-, meso-, and macropores from the early stages of the process, carbon dioxide produces highly microporous carbons, with broadening of the microporosity only for long activation times.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801848x

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7466–7473

Titre :	Electrochemical removal of rhodamine 6G by using RuO2 coated Ti DSA
Type de document :	texte imprimé
Auteurs :	Rita Farida Yunus, Auteur ; Yu-Ming Zheng, Auteur ; K.G. Nadeeshani Nanayakkara, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7466–7473
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Rhodamine 6G Electrochemical removal RuO2-coated Ti
Résumé :	In this study, electrochemical removal of rhodamine 6G containing wastewater using RuO2-coated Ti mesh as dimensionally stable anode is investigated. The effects of pH, supporting electrolyte, electrolyte concentration, applied current, and distance between electrodes on the removal efficiency were examined in a batch reactor. It is shown that NaCl is the best supporting electrolyte among NaCl, Na2SO4, NaClO4, and NaNO3. Lower solution pH and higher concentration of supporting electrolyte facilitate the treatment process. Small distance between electrodes greatly decreases the energy consumption. The decolorization efficiency of above 99.5% and the low energy consumption of 1.58 kWh/m3 can be achieved under the optimized experimental condition of NaCl concentration of 0.2 M, applied current of 1.0−1.9 A, pH < 6, and distance between electrode of 5 mm. The RuO2-coated Ti mesh anode is shown to have good recyclability and lifespan. A greater dye removal of 99.2% can be obtained by a continuous stirred-tank reactor with a HRT of 4 min. It is anticipated that the developed technology from this study can be further scaled up for full-scale treatment of industrial dye containing wastewater.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801719b

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7457–7465

Titre :	Clathrate hydrates : from laboratory science to engineering practice
Type de document :	texte imprimé
Auteurs :	Amadeu K. Sum, Auteur ; Carolyn A. Koh, Auteur ; E. Dendy Sloan, Auteur
Année de publication :	2009
Article en page(s) :	pp. 7457–7465
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Clathrate hydrates Thermodynamics Kinetics Rheological properties Structural properties
Résumé :	Clathrate hydrates have steadily emerged as an important field in the areas of flow assurance, energy storage and resource, and environment. To better understand the role of hydrates in all of these areas, knowledge developed in laboratory experiments must be effectively transferred to address the challenges related to hydrate formation, dissociation, agglomeration, and stability. This paper highlights the recent hydrate literature focusing on the thermodynamics, kinetics, structural properties, particle properties, rheological properties, and molecular mechanisms of formation. The foundation for continued understanding and development of hydrates in engineering practice will rely on laboratory measurements utilizing traditional and innovative tools capable of probing time-dependent and time-independent properties.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900679m

Industrial & engineering chemistry research / Paul, Donald R. . Vol. 48 N° 16

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