Catalogue en ligne Bibliothèque Ecole Nationale Polytechnique d'Alger

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6448–6452

Titre :	Multiphase, microdispersion reactor for the continuous production of methane gas hydrate
Type de document :	texte imprimé
Auteurs :	Patricia Taboada-Serrano, Auteur ; Shannon Ulrich, Auteur ; Phillip Szymcek, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6448–6452
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Hydrate reactor CO2 hydrate stream CH4 hydrate Seafloor process simulator
Résumé :	A continuous-jet hydrate reactor originally developed to generate a CO2 hydrate stream has been modified to continuously produce CH4 hydrate. The reactor has been tested in the Seafloor Process Simulator (SPS), a 72-L pressure vessel available at Oak Ridge National Laboratory. During experiments, the reactor was submerged in water inside the SPS and received water from the surrounding through a submersible pump and CH4 externally through a gas booster pump. Thermodynamic conditions in the hydrate stability regime were employed in the experiments. The reactor produced a continuous stream of CH4 hydrate, and based on pressure values and amount of gas injected, the conversion of gas to hydrate was estimated. A conversion of up to 70% was achieved using this reactor.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8019517

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6441–6447

Titre :	Saccharification of a potential bioenergy crop, phragmites australis (common reed), by lignocellulose fractionation followed by enzymatic hydrolysis at decreased cellulase loadings
Type de document :	texte imprimé
Auteurs :	Noppadon Sathitsuksanoh, Auteur ; Zhiguang Zhu, Auteur ; Neil Templeton, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6441–6447
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Biological saccharification Nonfood lignocellulosic biomass Phragmites Bioenergy
Résumé :	Cost-effective biological saccharification of nonfood lignocellulosic biomass is vital to the establishment of a carbohydrate economy. Phragmites australis (common reed) is regarded as an invasive perennial weed with a productivity of up to 18−28 tons of dry weight per acre per year. We applied the cellulose solvent- and organic solvent-based lignocellulose fractionation (COSLIF) to the stems and leaves of Phragmites and optimized the pretreatment conditions (e.g., temperature, reaction time, and biomass moisture content) through response surface methodology (RSM). The optimal pretreatment conditions were 85% (w/v) H3PO4, 50 °C, and 60 min, regardless of the biomass moisture contents from 5−15% (w/w). Glucan digestibility of the COSLIF-pretreated common reed was 90% at hour 24 at a low cellulase loading (5 filter paper units and 10 β-glucosidase units per gram of glucan). Under these conditions, the overall sugar yields were 88% for glucose and 71% for xylose, respectively. Cellulose accessibility to cellulase (CAC) was increased 93.6-fold from 0.14 ± 0.035 to 13.1 ± 1.1 m2 per gram of biomass with the COSLIF pretreatment. Results showed that cellulase concentrations could be reduced by 3-fold with only a slight reduction in sugar yield. This study suggested that Phragmites could be used as a carbon-neutral bioenergy feedstock, while its harvesting could help control its invasive growth and decrease nutrient pollution in adjacent waterways.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900291s

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6436–6440

Titre :	On the predictive ability of the new thermodynamics of electrolyte solutions
Type de document :	texte imprimé
Auteurs :	Grazyna Wilczek-Vera, Auteur ; Juan H. Vera, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6436–6440
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Electrolyte solutions Mixed salt systems
Résumé :	This work highlights the main elements of the new thermodynamic approach to electrolyte solutions and demonstrates its ability to make predictions for mixed salt systems. After a review of the state of affairs before the measurement of activities of individual ions, experimental set-ups used for these measurements are described and the essential elements of different methods used to reduce the data are discussed. The results of experiments carried to test a possible bias introduced by uncertainty in the values of the junction potential are emphasized. It is purported that the thermodynamic treatment proposed by Lin and Lee is of general application and ensures the thermodynamic consistency of correlations previously proposed for the individual ionic activities. It is shown that the use of a more complex form for the contribution of long-range interactions to ionic activities leads to a simpler form of the osmotic coefficient. As an example of application, the predictions of the equilibrium pressure over NaCl + KCl, NaBr + KBr, and NaCl + CaCl2 aqueous solutions, at different temperatures and compositions, are compared with independently measured experimental data.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9002238

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6432–6435

Titre :	Conductivities of CuSO4 and CdSO4 in sucrose/trehalose-water systems at 298.15 K
Type de document :	texte imprimé
Auteurs :	Kelei Zhuo, Auteur ; Yujuan Chen, Auteur ; Wenhao Wang, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6432–6435
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	CuSO4 CdSO4 Aqueous disaccharide Sucrose/trehalose-water systems
Résumé :	The conductivities of CuSO4 and CdSO4 in aqueous disaccharide (sucrose and trehalose) solutions were measured together with the densities, viscosities, and relative dielectric constants of the aqueous disaccharide solutions at 298.15 K. The limiting molar conductivities (Λ0) and association constants (KA) were derived from the Lee−Wheaton conductivity equation. From the obtained conductivity data, the values of the Walden product (Λ0η0) were also calculated. The ion−ion and ion−solvent interactions are discussed.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900041w

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6423–6431

Titre :	Enhanced mass transfer of CO2 into water : experiment and modeling
Type de document :	texte imprimé
Auteurs :	R. Farajzadeh, Auteur ; P. L. J. Zitha, Auteur ; J. Bruining, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6423–6431
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	CO2 Sub-surface water Mass transfer
Résumé :	Concern over global warming has increased interest in quantification of the dissolution of CO2 in (sub-)surface water. The mechanisms of the mass transfer of CO2 in aquifers and of transfer to surface water have many common features. The advantage of experiments using bulk water is that the underlying assumptions to the quantify mass-transfer rate can be validated. Dissolution of CO2 into water (or oil) increases the density of the liquid phase. This density change destabilizes the interface and enhances the transfer rate across the interface by natural convection. This paper describes a series of experiments performed in a cylindrical PVT-cell at a pressure range of pi = 10−50 bar, where a fixed volume of CO2 gas was brought into contact with a column of distilled water. The transfer rate is inferred by following the gas pressure history. The results show that the mass-transfer rate across the interface is much faster than that predicted by Fickian diffusion and increases with increasing initial gas pressure. The theoretical interpretation of the observed effects is based on diffusion and natural convection phenomena. The CO2 concentration at the interface is estimated from the gas pressure using Henry’s solubility law, in which the coefficient varies with both pressure and temperature. Good agreement between the experiments and the theoretical results has been obtained.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801521u

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6417–6422

Titre :	Selective separation of tocopherol homologues by liquid-liquid extraction using ionic liquids
Type de document :	texte imprimé
Auteurs :	Qiwei Yang, Auteur ; Huabin Xing, Auteur ; Yifeng Cao, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6417–6422
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Pocopherol homologues Liquid-liquid extraction Ionic liquid
Résumé :	Selective separation of tocopherol homologues was performed by liquid−liquid extraction, using ionic liquids (ILs) as extractants in the presence of diluent. The distribution coefficients and selectivities of tocopherols in the biphasic system were determined. A selectivity of δ-tocopherol to α-tocopherol up to 21.3 was achieved when using [bmim]Cl as extractant diluted by methanol. Considering the structural differences of tocopherols, the separation mechanism based on the hydrogen-bonding interaction between IL’s anion and the −OH group on the tocopherols was proposed. The separation efficiency of IL was greatly affected by its anion, and followed the order [bmim]BF4 < [bmim]CF3SO3 < [bmim]Cl under the same conditions, which is consistent with the ascending order of IL’s hydrogen-bond basicity strengths.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801847e

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6405–6416

Titre :	Hybrid cycles to purify concentrated feeds containing a strongly adsorbed impurity with a nonlinear isotherm : the PSA−TSA supercycle
Type de document :	texte imprimé
Auteurs :	Pradeep K. Sharma, Auteur ; Phillip C. Wankat, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6405–6416
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Adsorption process Non- or weakly adsorbing gas PSA−TSA supercycle
Résumé :	A new adsorption process is developed to remove a strongly adsorbing gaseous impurity that has a very nonlinear isotherm from a non- or weakly adsorbing gas. This process, a number of pressure-swing cycles with low purge ratios followed by thermal regeneration, is called a PSA−TSA supercycle because it consists of thermal cycles on top of PSA cycles. The PSA cycles never reach cyclic steady state by themselves, although the supercycle does reach cyclic steady state. A water/nitrogen mixture with zeolite 13X is taken as model system because water exhibits strongly nonlinear adsorption characteristics. At low feed concentrations (1000 ppm water), PSA works well and is the preferred method. At intermediate feed concentrations (4000 ppm water), TSA is the preferred method. The PSA−TSA supercycle is better than PSA and TSA in handling high solute concentrations in the feed (40 000 ppm water) and producing high-purity product (1 ppm water). PSA fails to meet this purity, and TSA has low productivity. The new hybrid cycle is promising for highly nonlinear systems with high solute concentrations in the feed.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801661w

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6387–6404

Titre :	Thermally coupled side-column configurations enabling distillation boundary crossing. 1. an overview and a solving procedure
Type de document :	texte imprimé
Auteurs :	Ilkka Malinen, Auteur ; Juha Tanskanen, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6387–6404
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Thermally coupled side-rectifier Side-stripper configurations Component sets Curved distillation boundary
Résumé :	In this paper, the thermally coupled side-rectifier and side-stripper configurations are studied in the separation of component sets with a curved distillation boundary. A solving procedure is introduced that can be used in the determination of the minimum total energy consumption for the studied complex separation structures. The results show that thermally coupled side-column configurations enable distillation boundary crossing with high product flow purities. In fact, the achievable purities are higher than is possible with conventional column sequences. It is also noted that in some methanol/ethanol/water separations the energy consumption of the thermally coupled side-stripper configuration may partly decrease with increasing methanol distillate purity.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800817n

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6372–6386

Titre :	Thermally coupled side-column configurations enabling distillation boundary crossing. 2. effects of intermediate heat exchangers
Type de document :	texte imprimé
Auteurs :	Ilkka Malinen, Auteur ; Juha Tanskanen, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6372–6386
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Thermally coupled side-column configurations Heat exchangers Curved distillation boundary
Résumé :	In this paper, the benefits of intermediate heat exchangers situated in thermally coupled side-column configurations are examined in the separation of component sets having a curved distillation boundary. The simulation results indicate that by incorporating an intermediate heat exchanger the distillation boundary crossing can be enhanced. In consequence, pure product flows may be achieved with decreased total energy requirement. It is also found that thermally coupled side-column configurations having an intermediate heat exchanger require less energy to carry out the desired separation than do the corresponding conventional direct and indirect column schemes. Regardless of the increased complexity and possibility for multiple steady states, intermediate heat exchangers always improve thermodynamic efficiency and widen the potential for heat integration. This paper complements the study started in Part 1 [Malinen, I.; Tanskanen, J. Thermally coupled side-column configurations enabling distillation boundary crossing. 1. An Overview and a solving procedure. Ind. Eng. Chem. Res. 2009, 48, DOI: 10.1021/ie800817n] of this series of papers.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800818y

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6363–6371

Titre :	Dual optimization strategy for N and P removal in a biological wastewater treatment plant
Type de document :	texte imprimé
Auteurs :	MinHan Kim, Auteur ; A. Seshagiri Rao, Auteur ; ChangKyoo Yoo, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6363–6371
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Nitrogen removal Phosphorus removal Biological nutrient removal process Systematic approach
Résumé :	A systematic approach is proposed to find optimal operational conditions for nitrogen and phosphorus (N, P) removal in a biological nutrient removal process. The approach is a dual optimization strategy using modeling, variable selection, design of experiments, and optimization with multiple response surface methodology. The study focused on determining interactive effects between independent variables for N and P removal, which were selected through a new sensitivity analysis considering the effluent quality index. After selecting key operational variables, a multiple response surface model based on a new desirability function was used for the dual optimization of both N and P removal. The proposed method was applied to a standard A2O process and obtained the optimized removal efficiencies of 78.0% and 80.0% for N and P, respectively. This study confirmed that the proposed dual optimization method was useful to systematically optimize N and P removal in a biological nutrient removal process and also can be applied to any other biological processes.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801689t

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6358–6362

Titre :	Influence of p-xylene (PX) accumulation on the operation of pure terephthalic acid (PTA) solvent dehydratic distillation column
Type de document :	texte imprimé
Auteurs :	Shaojun Li, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6358–6362
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Pure terephthalic acid P-xylene Dehydration distillation column
Résumé :	In the production of pure terephthalic acid, a tiny amount of reactant p-xylene may enter into the acetic acid dehydration distillation column through the feed stream. In normal operation, p-xylene will not leave the column from the top or bottom product. It will be accumulated in the top of dehydration distillation column and decanter. With the accumulation of p-xylene, the operation cost will be increased gradually, to ensure the purity specifications of the top and bottom products. To reduce the operation cost, it is necessary to cut down the concentration of p-xylene by draining some organic reflux and make up the pure entrainer intermittent. In this paper, reboiler duties at different concentrations of p-xylene in the reflux were analyzed. The optimal operation condition—that the concentration of p-xylene is decreased by draining some organic reflux when the mass fraction of p-xylene accumulation exceeds 0.15—had been suggested. Finally, the residue curves diagram of three key components in the top of the column was used to interpret the draining place of p-xylene.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900526n

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6346–6357

Titre :	An efficient mixed-integer linear programming scheduling framework for addressing sequence-dependent setup issues in batch plants
Type de document :	texte imprimé
Auteurs :	Kopanos, Georgios M., Auteur ; José Miguel Lainez, Auteur ; Puigjaner, Luis, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6346–6357
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Mixed-integer linear programming scheduling framework Sequence-dependent setup times
Résumé :	Setup times and/or costs appear in a plethora of industrial and service applications. Sequence-dependent setup times and costs entail significantly complex scheduling problems. In this paper, a new continuous time precedence-based mixed-integer linear programming scheduling framework is developed for dealing with sequence-dependent setup time and/or cost issues. This model is based on the unit-specific general precedence concept, which is introduced in this paper. Several case studies are carried out in order to highlight the efficiency and the special features of the proposed model. Comparisons were made with the existing precedence-based formulations. Medium-sized scheduling problems can be solved by the proposed framework with relatively low computational effort.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801127t

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6339–6345

Titre :	Decomposability of the control structure design problem of recycle systems
Type de document :	texte imprimé
Auteurs :	Marcell Horvath, Auteur ; Péter Mizsey, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6339–6345
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Control structure design Whole process simultaneously
Résumé :	The control structure design is an important part of process synthesis tasks. The design becomes more difficult if recycle is present in the process to be controlled. The objective of this work is to clear up if the control structure design should be completed for the whole process simultaneously or it can be decomposed into subproblems involving only one unit of the whole system. Investigations show that the recycle can have an effect on the control structure that complicates the design problem. Simple case studies and exhaustive investigation of the industrial control problem are completed. Our investigations prove that decomposability can be applied simplifying the proper pairing of the controlled and manipulated variables, and this can facilitate the control structure design problem.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800976v

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6327–6338

Titre :	A modified extended recursive least-squares method for closed-loop identification of FIR models
Type de document :	texte imprimé
Auteurs :	Christopher L. Betts, Auteur ; Srinivas Karra, Auteur ; M. Nazmul Karim, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6327–6338
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Closed-loop conditions Time-varying bias term Least-squares algorithm
Résumé :	Performing a plant test under closed-loop conditions is desirable for model identification because production loss and safety problems may result when control loops are opened during plant testing. However, identification of models from closed-loop data is more difficult compared to identifying models from open-loop data because of the correlation between the colored noise and the process inputs created by the feedback. A novel method for identifying models using closed-loop data is proposed, which employs a time-varying bias term with a moving average dynamic component as the model structure. Then identification for this process model is performed using a modified extended recursive least-squares algorithm to eliminate the bias from the process parameter estimates. Evaluation of the proposed algorithm is performed using simulation case studies involving multivariable processes controlled by either diagonal PI controllers or a model predictive controller (DMCPlus). The simulation results showed that the proposed method is robust with respect to measurement noise and is able to identify high quality models from closed-loop data.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800922w

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6321–6326

Titre :	Optimizing the initial conditions to improve the dynamic flexibility of batch processes
Type de document :	texte imprimé
Auteurs :	Hua Zhou, Auteur ; Xiuxi Li, Auteur ; Yu Qian, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6321–6326
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Initial operation conditions Batch processes Dynamic flexibility analysis
Résumé :	It is shown in this paper that by changing the initial operation condition of batch processes, the dynamic performance of the system can be varied largely. The initial operation conditions are often ignored in design of batch processes for flexibility against disturbances or parameter variations. When the initial conditions are not rigid, as in the case of a batch reactor where the initial reaction temperature is quite arbitrary, optimization can also be applied to determine the “best” initial condition to be used. Problems for dynamic flexibility analysis, including initial conditions and process operation, can be formulated as dynamic optimization problems. If the initial conditions are considered, the conditions can be transferred into control variables in the first step of optimization. The solution of the dynamic optimization is based on the Runge-Kutta integration algorithm and decomposition search algorithm. This method, as illustrated and tested with two highly nonlinear chemical engineering problems, enables the optimal solution to be determined.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8006424

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6315–6320

Titre :	Anion-exchange reactions of layered double hydroxides : interplay between coulombic and H-bonding interactions
Type de document :	texte imprimé
Auteurs :	S. V. Prasanna, Auteur ; P. Vishnu Kamath, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6315–6320
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Layered double hydroxides Anions Nonequilibrated conditions Cl− NO3− ions
Résumé :	The NO3−- and Cl−-containing layered double hydroxides (LDHs) of Mg with Al interact weakly with anions in solution under equilibrated conditions and yield a type V isotherm. The uptake of anions under nonequilibrated conditions varies monotonically with the layer charge when the outgoing anion is NO3−, whereas it goes through a maximum when the outgoing anion is Cl−. These observations suggest that Coulombic interactions play a dominant role in Cl−-LDHs, whereas weak interactions governing the mode of intercalation of NO3− ions influence the exchange reactions of NO3−-LDHs. These studies have significant implications for the remediation of insidious anions by LDHs.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9004332

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6308–6314

Titre :	Promoted and controllable self-assembly of hydrolyzed siloxane and triblock copolymer under organic polyhydroxy acids
Type de document :	texte imprimé
Auteurs :	Jin Jun Li, Auteur ; Zhen Mu, Auteur ; Chi He, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6308–6314
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Polyhydroxy organic acids Tartaric acid Citric acid
Résumé :	Large-molecule polyhydroxy organic acids such as tartaric acid and citric acid were found to significantly promote the cooperative formation of mesoporous silica SBA-15 with homogeneous well-defined hexagonal mesostructure under much weaker acidities without addition of volatile inorganic acids; therefore a novel environmental benign route for SBA-15 synthesis was developed. It is suggested that the polar groups of polyhydroxy acid molecules can greatly strengthen the assembly interactions between the silica species and the triblock copolymer by providing hydrogen bonding. More interestingly, by controlling the strength of hydrogen-bonding interaction that is dependent on the concentration of carboxylic acids, the particle size of the product can be tailored. The silica with small particle size synthesized with a small amount of polyhydroxy acids was favorable support of palladium catalyst for the complete oxidation of volatile organic compounds in atmosphere, probably due to the facilitated diffusion of reactant molecules.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900100g

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6303–6307

Titre :	Wettability controlled fabrication of highly transparent and conductive carbon nanotube/silane sol hybrid thin films
Type de document :	texte imprimé
Auteurs :	Joong Tark Han, Auteur ; Sun Young Kim, Auteur ; Hee Jin Jeong, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6303–6307
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Carbon nanotube Methyltrimethoxysilane sol mixture H2O2-treated FWCNT solution Silane sol
Résumé :	The stable few-walled carbon nanotube (FWCNT)/methyltrimethoxysilane sol mixture solution was successfully prepared by direct mixing of H2O2-treated FWCNT solution and silane sol. The stabilization of the solution was achieved by the intermolecular interaction between the hydroxyl groups on the FWCNTs and silanol groups in silane sol. FWCNT/silane sol hybrid thin films were then deposited on the model surfaces treated with piranha solution and silane molecules containing different end functionalities of NH2, CH3, and CF3 by spraying. The water contact angles of the model surfaces could be tuned from 112° to below 5°. It was found that a hydrophilic surface is more effective than a hydrophobic one in improving the conductivity of thin films by forming the uniform film structure, while the dewetting of the FWCNT/silane sol mixture solution on the most hydrophobic surface (CF3) slightly improved the transparency of the films.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900301v

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6296–6302

Titre :	Chemistry and structure of the passive film on mild steel in CO2 corrosion environments
Type de document :	texte imprimé
Auteurs :	Jiabin Han, Auteur ; David Young, Auteur ; Hendrik Colijn, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6296–6302
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Passivation process Electrochemical glass cell Grazing incidence X-ray diffraction Transmission electron microscopy
Résumé :	The passivation process was carried out and monitored employing a three electrode electrochemical glass cell. Surface analysis using grazing incidence X-ray diffraction (GIXRD) elucidated that trace magnetite in the dominant siderite (FeCO3) was responsible for the passivation. Transmission electron microscopy (TEM) with the energy dispersive X-ray fluorescence (EDX) technique was used to determine the structure of the passive layer and confirm its chemistry. A passive phase tens of nanometers thick was observed beneath iron carbonate scale and at the crystal boundaries. Scanning transmission electron microscopy (STEM)/EDX profiles suggest that this phase is not a carbonate containing compound since only oxygen and iron were observed. This indicates that the possible chemical compound for the passive phase is an iron oxide, agreeing with the previous GIXRD surface analysis. Fe3O4 as a passive film was confirmed.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801819y

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6291–6295

Titre :	Mg-Zn and Mn-Zn ferrites derived from coil core materials as new precursors for catalysts of primary alcohols transformations
Type de document :	texte imprimé
Auteurs :	Roman Klimkiewicz, Auteur ; Kazimierz Przybylski, Auteur ; Jan Baran, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6291–6295
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Mg-Zn Mn-Zn Microelectronic ferrite materials Alcohols transformation Catalysts
Résumé :	Two new precursor materials, (Mg0.63Zn0.37)(Mn0.1Fe1.8)O3.85 (hereafter Mg−Zn) and (Mn0.55Zn0.35Fe0.1)Fe2O4 (hereafter Mn−Zn), derived from the microelectronic ferrite materials studied earlier by us, were found to be catalytically active in primary alcohols transformation. Both Mg−Zn and Mn−Zn ferrites reveal dehydrogenating features, transforming a primary alcohol into an aldehyde, but they differ with respect to subsequent bimolecular condensation to symmetric ketone. The difference in selectivity can be tentatively explained by the different dispersion of surface both Lewis acidic centers and reducing centers as well as the presence of a strong synergic effect between these centers. The materials were tested by XRD, TPR, IR, and BET methods.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801979w

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6287–6290

Titre :	Synthesis of dimethyl pimelate from cyclohexanone and dimethyl carbonate over solid base catalysts
Type de document :	texte imprimé
Auteurs :	Dudu Wu, Auteur ; Zhi Chen, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6287–6290
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Dimethyl pimelate Carbomethoxycyclohexanone Solid base catalysts
Résumé :	The synthesis of dimethyl pimelate (DMP) was carried out from cyclohexanone and dimethyl carbonate in the presence of solid base catalysts. The results showed that the intermediate carbomethoxycyclohexanone (CMCH) was produced from cyclohexanone with DMC in the first step, and then CMCH further converted to DMP by reacting with methoxide group. The function of basic catalysts was mainly attributed to the activation of cyclohexanone via the abstraction of proton in the α position by base sites, and solid base with moderate strength, such as MgO, facilitated the formation of DMP.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801852e

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp.

Titre :	The kinetics and stoichiometry of the reaction between hypochlorous acid and chlorous acid in mildly acidic solutions
Type de document :	texte imprimé
Auteurs :	Ville Tarvo, Auteur ; Tuula Lehtimaa, Auteur ; Susanna Kuitunen, Auteur
Année de publication :	2009
Article en page(s) :	pp.
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Hypochlorous acid Chlorous acid Stoichiometry Kinetics
Résumé :	The kinetics and stoichiometry of the reaction between hypochlorous acid and chlorous acid was studied under mildly acidic conditions (pH = 2.5−4.7). The experiments were conducted in dilute solutions (10−4−10−3 M) at T = 5−25 °C. External buffer compounds were not used. Chlorous acid, chlorine dioxide, and chlorate concentrations were monitored with titrimetric methods. Rate coefficients and activation energies were determined for the five main steps of the kinetic model (others were adopted from literature). Both hypochlorous acid and chlorine were found to react at an appreciable rate with chlorous acid/chlorite. Chloride ion was found to promote both the overall reaction rate and chlorine dioxide/chlorate ratio. The results may be exploited in optimizing the red-ox efficiency of technical chlorine dioxide bleaching processes.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801798m

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6273–6279

Titre :	Influence of preparation method on the nanocrystalline porosity of α-Al2O3 and the catalytic properties of Pd/α-Al2O3 in selective acetylene hydrogenation
Type de document :	texte imprimé
Auteurs :	Sataporn Komhom, Auteur ; Okorn Mekasuwandumrong, Auteur ; Joongjai Panpranot, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6273–6279
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Nanocrystalline α-Al2O3 powder Crystallite sizes
Résumé :	Nanocrystalline α-Al2O3 powder with average crystallite sizes of 34−68 nm have been synthesized by three different methods, namely, solvothermal, sol−gel, and precipitation. Although the smallest crystallite size of α-Al2O3 was obtained via the sol−gel synthesis, the α-Al2O3 sol−gel possessed the least amount of specific surface area and pore volume. A narrow pore size distribution with an average pore diameter of 15 nm can be obtained via solvothermal method, whereas the precipitation method yielded α-Al2O3 with larger pore size and a wider pore size distribution. When used as a support for palladium catalysts, the α-Al2O3 solvothermal provided the highest palladium dispersion and the best catalyst performance in selective hydrogenation of acetylene. The catalytic properties of Pd/α-Al2O3 solvothermal were improved, in terms of both acetylene conversion and ethylene selectivity. As shown by temperature program studies, the use of solvothermal-derived α-Al2O3 facilitated H2 reduction at low temperature and the desorption of ethylene and CO.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801784f

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6262–6272

Titre :	Experimental performance and modeling of a new cooled-wall reactor for the supercritical water oxidation
Type de document :	texte imprimé
Auteurs :	M. Dolores Bermejo, Auteur ; Daniel Rincon, Auteur ; Angel Martin, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6262–6272
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Cooled-wall reactor Supercritical water oxidation
Résumé :	For the commercial application of the supercritical water oxidation (SCWO), new reactors that are able to withstand the harsh operational conditions of the process must be developed. In this work, a new scaled-up design of the cooled-wall reactor (CWR) is presented, which isolates the temperature and pressure stresses caused by SCWO processes. The new reactor consists of a series of chambers designed as a heat exchanger to maximize the residence time and minimize the temperature gradient inside the reactor, allowing a better thermal protection of the pressure shell. This reactor has been implemented in a demonstration scale plant located in the industrial site of a waste management company. Experimental results obtained in this plant with five prototypes of the reactor are presented, explaining the strong and weak points of the designs and the modifications proposed to overcome the operational problems. Experimental results obtained working with oxygen and air as an oxidant and feeds containing isopropyl alcohol and mixtures of isopropyl alcohol/ammonia are thoroughly examined and compared. To have a better understanding of the behavior of the reactor a mathematical model specifically developed for the new reactor is presented.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900054e

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6256–6261

Titre :	Artificial neural network (ANN)-aided optimization of ZSM-5 catalyst for the dimethyl ether to olefin (DTO) reaction from neat dimethyl ether (DME)
Type de document :	texte imprimé
Auteurs :	Kohji Omata, Auteur ; Yuichiro Yamazaki, Auteur ; Yuhsuke Watanabe, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6256–6261
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	ZSM-5 catalyst Dimethyl ether Olefin
Résumé :	A ZSM-5 catalyst for light olefin synthesis from dimethyl ether (the reaction of dimethyl ether (DME) to olefin, abbreviated as DTO) was developed. In comparison with the reaction of DTO from diluted dimethyl ether (abbreviated as Diluted-DTO), lower light olefin selectivity and shorter catalyst life are the drawbacks of the reaction of DTO from neat (90 vol %) DME (abbreviated as Neat-DTO). After the effects of Si/Al ratio of zeolite, DME concentration, gas hourly space velocity (GHSV) of gas feed, and Si/Al ratio on the activity of calcium-incorporated ZSM-5 were examined, additives were screened using the physicochemical properties of the additive elements and an artificial neural network. The addition of boron or phosphorus to ZSM-5 improved the catalyst life. The catalyst composition such as Si/Al, Si/Ca, Si/P, and Si/B was then optimized for longer catalyst life, using an L9 orthogonal array and an artificial neural network (ANN). Grid search was applied to find the maximum catalyst life. The catalyst life of H−Ca-ZSM-5 (Si/Al = 250, Si/Ca = 20, Si/P = 400, Si/B = 200) was 146 h when Neat-DTO was performed at 803 K and GHSV = 1000 h−1. The life is comparable to that of the catalyst supplied to Diluted-DTO.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801757p

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6248–6255

Titre :	Preparation of NiFeB nanoalloy catalysts and their applications in liquid-phase hydrogenation of p-chloronitrobenzene
Type de document :	texte imprimé
Auteurs :	Chen, Yu-Wen, Auteur ; Natarajan Sasirekha, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6248–6255
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	NiFeB nanoalloy catalysts Chemical reduction method Metal acetates P-chloronitrobenzene Hydrogenation
Résumé :	A series of NiFeB nanoalloy catalysts were prepared by chemical reduction method using metal acetates as the starting materials, and NaBH4 as the reducing agent. The amorphous metal materials, combining the features of amorphous and nanometer materials, have more surface atoms and a higher concentration of coordinately highly unsaturated sites. Sodium borohydride in excess amount was added dropwise into the mixture to ensure full reduction of metal cations. The catalysts were characterized with X-ray diffraction, nitrogen sorption, transmission electron microscopy, and X-ray photoelectron spectroscopy. The hydrogenation of p-chloronitrobenzene was carried out in a batch reactor at 1.2 MPa H2 pressure and 323−393 K. The Ni/Fe molar ratios in the starting materials affected the concentration of boron bounded to the nickel and iron metals, resulting in the difference in surface area, electronic structures of the metals, and the catalytic activities of the catalysts. The addition of iron in NiB catalyst could reduce the particle of the nickel metal, suppress the growth of crystalline structure of NiFeB, and help the NiFeB catalyst to maintain its amorphous state. On the basis of the electron transfer between elemental nickel and boron, Ni in NiFeB had more d-band electrons and higher electron density than in NiB; therefore, it also has higher activities of hydrogenation of the nitro group than does NiB.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801624a

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6237–6247

Titre :	Kinetics of neopentyl glycol esterification with different carboxylic acids
Type de document :	texte imprimé
Auteurs :	Kari Vahteristo, Auteur ; Sylvie Maury, Auteur ; Arto Laari, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6237–6247
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Neopentyl glycol esterification Carboxylic acids
Résumé :	The aim of this work was to study the reaction kinetics of neopentyl glycol esterification with different carboxylic acids (propionic acid, isobutyric acid and 2-ethylhexanoic acid). The experiments were carried out in a batch reactor as reactive distillation removing continuously one reaction product (water) by purging nitrogen through the reactor. Commercial heterogeneous gellular (Dowex 50WX2) and macroreticular (Amberlyst 15) type resins and homogeneous para-toluene sulfonic acid were compared as catalysts. The gellular type resin was dried before loading into the reactor. When performing esterification of neopentyl glycol with different acids the observed formation of monoester was clearly much faster than the consecutive esterification of monoester to diester. A disproportionation reaction was also found to take place. The reliability of the estimated Arrhenius parameters was analyzed using Bayesian inference and Markov chain Monte Carlo methods (MCMC). MCMC analysis was also used to study uncertainties in the model predictions and in some additional parameters, such as reaction rate constants calculated from the estimated parameters. This cannot be done by classical regression analysis.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801920m

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6229–6236

Titre :	Photocatalytic treatment of air : comparison of various TiO2, coating methods, and supports using methanol or n-octane as test pollutant
Type de document :	texte imprimé
Auteurs :	Jérôme Taranto, Auteur ; Didier Frochot, Auteur ; Pierre Pichat, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6229–6236
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	TiO2 Coating method Air photocatalytic purification/deodorization
Résumé :	We have investigated the effects of the TiO2 type and coating method, two important factors for TiO2-based photocatalytic purification/deodorization of air. First, two TiO2 powders (PC500 and 105) designed by Millennium Chemicals for photocatalysis were compared with Degussa P25 TiO2, a common reference, for removing methanol or n-octane in a flowing dry mixture of O2 (20 v/v %) and N2. Under the conditions used, the differences were very small. For methanol mineralization, PC500 (the highest surface area sample) was, however, more efficient, which is attributed to increased adsorption of methanal (main intermediate product). Second, PC500 and 105 coated on a fibrous tissue (Ahlstrom) using a silica binder were tested for removing methanol in the O2 + N2 mixture in a batch reactor. Increasing the SiO2 wt % from 20 to 50, at equal mass of TiO2 + SiO2, was detrimental but not markedly, and the interest of using PC500 preferentially to PC105 to mineralize methanol was confirmed. Third, experimental design was used to optimize the thickness and quality of P25 coatings on quartz (or similarly on aluminum), which were obtained by several dipping/drying steps followed by a final calcination. For the optimized coatings, methanol or n-octane disappearance (batch reactor) and mineralization reached a maximum for three dip-coating steps (ca. 0.6 μm coating thickness, likely corresponding to UV light maximum penetration depth).
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900014f

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6224–6228

Titre :	Influence of crystallization of nano TiO2 prepared by adsorption phase synthesis on photodegradation of gaseous toluene
Type de document :	texte imprimé
Auteurs :	Ting Wang, Auteur ; Xin Jiang, Auteur ; Yanxiang Wu, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6224–6228
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	TiO2/SiO2 Gaseous toluene Catalytic activity Photocatalytic activity
Résumé :	TiO2/SiO2 was prepared by adsorption phase synthesis, and its photocatalysis on degradation of gaseous toluene was studied. The concentration of water added in preparation and temperature in calcination were changed to regulate formation of anatase TiO2. Ti contents in samples and grain size of anantase TiO2 were measured, and the catalytic activity in photodegrading gaseous toluene was characterized. The photocatalytic activity increased sharply when the calcination temperature increased to 500 °C or the volume of water added in preparation reached 1.5 mL. XRD analysis indicated that the crystal phase transformation of TiO2 from anatase to rutile was restrained and TiO2 remained in the form of anatase even after being sintered at 900 °C. The high constant photocatalytic activity from 500 to 900 °C was attributed to the stability of anatase TiO2 in crystal size and phase transformation.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801974y

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6216–6223

Titre :	Surface functionalization of chitosan nanospheres via surface-initiated AGET ATRP mediated by iron catalyst in the presence of limited amounts of air
Type de document :	texte imprimé
Auteurs :	Fan Tang, Auteur ; Lifen Zhang, Auteur ; Jian Zhu, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6216–6223
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Chitosan nanospheres Iron(III)-mediated atom Electron transfer
Résumé :	A novel method of surface modification of solids was first developed via iron(III)-mediated atom transfer radical polymerization with activators generated by electron transfer (AGET ATRP) on the surfaces of chitosan nanospheres (CTSNSs) with an average diameter of 80 nm using FeCl3·6H2O as the catalyst, PPh3 as the ligand, and ascorbic acid (VC) as the reducing agent in the presence of a limited amount of air. The homopolymer poly(methyl methacrylate) (PMMA) and amphiphilic block copolymer poly(methyl methacrylate)-b-poly(poly(ethylene glycol) methyl ether methacrylate) (PMMA-b-P(PEGMA)) were grafted onto the surfaces of the CTSNSs. Well-defined polymer chains were grown from the CTSNS surfaces to yield individual nanospheres composed of a chitosan core and a well-defined, densely grafted outer PMMA or PMMA-b-P(PEGMA) layer. The kinetics of surface-initiated AGET ATRP of MMA in the presence of a limited amount of air was investigated. A linear kinetic plot for the homopolymer, linear increase of molecular weight (Mn) with conversion, and linear plot of grafted percentage verse time were observed. The chemical composition of the nanosphere surfaces at different surface modification stages was validated by Fourier transform infrared (FT-IR) spectra and X-ray photoelectron spectroscopy (XPS).
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801935p

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6212–6215

Titre :	Cellulose triacetate optical film preparation from ramie fiber
Type de document :	texte imprimé
Auteurs :	Xiushan Fan, Auteur ; Zhong-Wen Liu, Auteur ; Jian Lu, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6212–6215
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Cellulose triacetate optical films Ramie fiber Biomass
Résumé :	A new route for the preparation of cellulose triacetate (CTA) optical films from the biomass of ramie fiber has been found with environmental benefits. CTA with a degree of substitution (DS) of 2.81−2.92 was prepared by the reaction of acetic anhydride with ramie fiber catalyzed by sulfuric acid in acetic acid solution at 55 °C. The CTA film was prepared by casting the solution of CTA dissolving in dichloromethane on the culture disk via spreading the solution through a syringe. The structure and properties of CTA and its film were investigated by Fourier transform infrared (FT-IR), ultraviolet (UV), X-ray diffraction (XRD), nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and titration. It was found that the CTA films prepared from ramie fiber shows a high transparency of 89% and excellent mechanical properties with stress measurements of 31.04−47.80 MPa and strain of 3.99−5.22%. The CTA films prepared from ramie fiber are suitable as protective films for the liquid crystal displays (LCD).
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801703x

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6203–6211

Titre :	Reactions of chemical warfare agent simulants in the common ion binary ionic liquid 1,2-dimethyl-3-propylimidazolium/copper(II) bis(trifluoromethylsulfonyl)amide
Type de document :	texte imprimé
Auteurs :	John S. Wilkes, Auteur ; Patrick J. Castle, Auteur ; Joseph A. Levisky, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6203–6211
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Ionic liquids Organic solvents Hydrogen peroxide Diisopropylfluorophosphate Bis(2-ethylhexyl) phosphite 2-chloroethylphenyl sulfide
Résumé :	Ionic liquids have the potential for being ideal alternatives for organic solvents in chemical warfare agent reactions and demilitarization processes. They are considered to be an excellent substitute, because of their extraordinarily wide liquid range, low melting points, chemical and thermal stability, high conductivity, and nonvolatility. In addition, many have excellent hydrophobic properties and immiscibility with water and offer the opportunity to isolate the chemical agents and reaction products from the environment. In this report, we describe a two-step process in which chemical warfare simulants are reacted with hydrogen peroxide (H2O2) followed by basic methanol in a common ion binary ionic liquid that consists of 1,2-dimethyl-3-propylimidazolium bis(trifluoromethylsulfonyl)amide and copper(II) bis(trifluoromethylsulfonyl)amide. The chemical agent simulants used in this study are diisopropylfluorophosphate, bis(2-ethylhexyl) phosphite, and 2-chloroethylphenyl sulfide, which simulate agents GB, VX, and HD, respectively. Initially, H2O2 is added to the mixture of simulants and ionic liquid to remove 2-chloroethylphenyl sulfide, followed by the addition of methanolic tetramethylammonium hydroxide hydrate (TMAOH·5H2O) (basic methanol) to eliminate diisopropylfluorophosphate and bis(2-ethylhexyl) phosphite. The reactions were monitored by liquid chromatography/mass spectroscopy time-of-flight (LC/MS-TOF), coupled with ultraviolet (UV) diode array detection. Gas chromatography/mass spectroscopy (GC/MS) was used to aid in product identification.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801650n

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6197–6202

Titre :	Composite sorbent of methanol “lithium chloride in mesoporous silica gel” for adsorption cooling machines : performance and stability evaluation
Type de document :	texte imprimé
Auteurs :	Larisa G. Gordeeva, Auteur ; Angelo Freni, Auteur ; Yuri I. Aristov, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6197–6202
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Methanol lithium chloride Mesoporous silica gelAdsorption cooling machines Thermogravimetric technique
Résumé :	In this paper, a novel composite sorbent of methanol “lithium chloride in mesoporous silica gel” is proposed for adsorption cooling machines. Methanol sorption isotherms were measured by a thermogravimetric technique. This composite demonstrated outstanding methanol sorption ability (up to 0.6 g of methanol per 1 g of dry sorbent). The thermodynamic coefficient of performance (COP), calculated by mathematical modeling for a basic cooling cycle, can reach 0.72 at desorption temperature of 343 K. The real performance was measured by testing this novel material in a lab-scale adsorption chiller. The specific cooling power of 210−290 W/kg and real cooling COP of 0.32−0.4 were obtained. Cycling stability of the sorbent was successfully verified. Such results indicate that the new composite sorbent “lithium chloride in mesoporous silica gel” can be recommended for application in adsorption cooling machines driven by low temperature heat.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8016303

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6188–6196

Titre :	Congo red biosorption on palm kernel seed coat
Type de document :	texte imprimé
Auteurs :	Nurudeen A. Oladoja, Auteur ; Akinola K. Akinlabi, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6188–6196
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Palm kernel coat Congo Red attenuation Aqueous stream Batch sorption system
Résumé :	Palm kernel coat (PKC), a waste product of oil palm production, was studied as a biosorbent for Congo Red (CR) (an anionic dye) attenuation in an aqueous stream. A batch sorption system was used, and the system variables studied included initial CR concentration and PKC dosage. A batch sorption model, based on the assumption of pseudo-first-order and pseudo-second-order mechanisms, was applied to understand the sorption dynamics of CR onto PKC and to predict the rate constant of sorption, the equilibrium sorption capacity, and the initial sorption rate when the two process variables were optimized. The linear coefficient of determination (r2) and the nonlinear chi-square test (χ2) were used to assess the fitting of the sorption dynamics to either model. An equation was developed using the pseudo-second-order model, which predicts the amount of CR at any contact time and initial concentration within the given range. The rate-limiting step of the sorption reaction was also determined using the intraparticle diffusion, liquid film diffusion, and Boyd kinetic models. The results obtained showed that intraparticle diffusion becomes rate controlling at low concentration while at high concentration film diffusion is the main rate-controlling parameter. The results of the batch desorption studies showed that chemisorption played a prominent role in the sorption process. The elution curve obtained from the continuous desorption studies showed that the elution rate was fast and high elution efficiency could be obtained with 0.1 M CH3COOH as an eluting solvent.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801003v

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6173–6187

Titre :	Affinity of polymer-supported reagents for lanthanides as a function of donor atom polarizability
Type de document :	texte imprimé
Auteurs :	Yijia Yang, Auteur ; Spiro D. Alexandratos, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6173–6187
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Lanthanide-ion affinities Donor atoms Polymer-supported reagents
Résumé :	This review correlates lanthanide-ion affinities with the polarizability of the donor atoms on immobilized ligands to gain an insight into the design of lanthanide-selective polymer-supported reagents. Comparison with the affinities for actinide ions clarifies the correlation. Polymers with different ligands are classified into four categories, based on an increasing order of donor atom polarizability: oxygen, oxygen and nitrogen, nitrogen, and sulfur. Hard−soft acid−base theory is an important determinant of ion−ligand affinities. Additional factors that affect complexation levels include counterion coordination to the metal, protonation of the ligand, and hydration. Selectivity for the lanthanide ions may be engineered into polymer-supported reagents by introducing phosphonic acid ligands.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900074t

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6162–6172

Titre :	Review of recent developments in solid acid, base, and enzyme catalysts (heterogeneous) for biodiesel production via transesterification
Type de document :	texte imprimé
Auteurs :	Rajabathar Jothiramalingam, Auteur ; Ming Kuang Wang, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6162–6172
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Solid catalysts Heterogeneous catalysis Biodiesel production
Résumé :	Development of new and effective solid catalysts (solid acid base to immobilized enzyme) is necessary for renewable and green energy production. The various choices of heterogeneous solid catalysis were reported recently, and the specific research outcomes of trans-esterification on heterogeneous catalysis are discussed in the present article. The studies on biodiesel production are mainly focused on the following aspects: (i) examining the appropriate oil source, (ii) establishing the adequate alcohol to oil molar ratio, and (iii) evaluating the available solid acid catalysts, solid base catalysts, and lipase immobilized enzyme catalysts. Although homogeneous catalysis are superior in terms of reaction rate compared to heterogeneous catalysis, the focus of research on development of solid catalysts for heterogeneous catalytic transesterification is directed from the point of easy process and possible adoption for large scale production. The scope of this presentation is to examine these aspects in detail and to provide a comprehensive outlook on the aspects mentioned.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801872t

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6145–6161

Titre :	Iron and copper recovery/removal from industrial wastes : a review
Type de document :	texte imprimé
Auteurs :	Archana Agrawal, Auteur ; S. Kumari, Auteur ; K.K. Sahu, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6145–6161
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Steel sheets Iron oxide scale generates Waste sulfate/chloride pickle liquor
Résumé :	Surface finishing of steel sheets and strips for the removal of iron oxide scale generates a huge amount of waste sulfate/chloride pickle liquor. Similarly large quantity of bleed stream is generated in the electrolysis industries due to the build up of acidity and metal impurity. The nature of the waste generated has become complex and hazardous in nature. Their impacts on ecological bodies are noticeable due to their toxic nature which is an alarming issue to the environmentalist. Hence, their treatment before disposal is mandatory. With the increasing demand for metals in industry and the depletion of land based resources, the focus of the research community is on the development of new approaches for the recovery of metal values from waste and recycle the water back to the system or dispose of it safely. This paper is a critical review on the waste streams generated from iron and steel industries and copper electrorefining industries. Various aspects on the metal value recovery from these wastes are being dealt with. The main focus is on iron recovery from waste pickle liquor and copper recovery from copper electroplating/electrorefining units by solvent extraction methods. Various solvents used for metal extraction are discussed here.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900135u

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6137–6144

Titre :	A modified network component analysis (NCA) methodology for the decomposition of X-ray scattering signatures
Type de document :	texte imprimé
Auteurs :	Ian Tolle, Auteur ; Xinqun Huang, Auteur ; Yvonne A. Akpalu, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6137–6144
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Polymeric materials Optimization-based methodology
Résumé :	In this work, we present an optimization-based methodology to identify network structure−process relationships in polymeric materials, to provide a robust understanding of how processing conditions affect their structural domains. The approach is largely inspired by network component analysis (NCA), which was originally developed in 2003 [Liao et al. Proc. Natl. Acad. Sci., U.S.A. 2003, 100, 15522−15527] to infer unobservable phenomena using large multivariate datasets. The fundamental assumption in NCA is that the connective relationship between desired unobservable phenomena and measured data is based on a largely known bipartite network topology. However, in many such analyses, this topology is either partially or completely unknown. To address this issue, the original NCA problem is reformulated as a mixed-integer nonlinear program (MINLP). Optimal solutions of the MINLP formulation provide network topologies and physically meaningful component signatures that correspond to the best possible data reconstruction. We demonstrate this approach for the analysis of wide-angle X-ray scattering (WAXS) data from a branched copolymer system. The copolymer samples vary in regard to side-chain length and isothermal crystallization temperature. Using our analysis, we isolate crystalline and amorphous components and observe their temperature-dependent variation. Good agreement is achieved between the degree of crystallinity calculated by this NCA-based decomposition and the experimentally reported values.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8012715

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6126–6136

Titre :	Nonlinear model-based control of an experimental reverse-osmosis water desalination system
Type de document :	texte imprimé
Auteurs :	Alex R. Bartman, Auteur ; Panagiotis D. Christofides, Auteur ; Yoram Cohen, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6126–6136
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Reverse-osmosis membrane water desalination system Nonlinear model-based control system
Résumé :	This work focuses on the design and implementation of a nonlinear model-based control system on an experimental reverse-osmosis (RO) membrane water desalination system to address large set-point changes and variations in feedwater salinity. A dynamic nonlinear lumped-parameter model is derived using first-principles, and its parameters are computed from experimental data to minimize the error between model predictions and experimental RO system response. This model then is used as the basis for the design of a nonlinear control system, using geometric control techniques. The nonlinear control system is implemented on the experimental RO system, and its set-point tracking and disturbance rejection capabilities are successfully evaluated.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900322x

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6112–6125

Titre :	Dynamics and control of a tubular solid-oxide fuel cell
Type de document :	texte imprimé
Auteurs :	S. Ahmad Hajimolana, Auteur ; Masoud Soroush, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6112–6125
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Tubular solid oxide fuel cell system Dynamic compartmental model Dynamic outlet voltage
Résumé :	This paper presents a study of the dynamic behavior and control of a tubular solid oxide fuel cell system. A dynamic compartmental model that is based on first principles is developed. The model accounts for diffusion processes, inherent impedance, transport (heat and mass transfer) processes, electrochemical processes, anode and cathode activation polarizations, and internal reforming/shifting reactions, among others. Dynamic outlet voltage, current, and fuel-cell−tube temperature responses of the cell to step changes in external load resistance and conditions of the feed streams are presented. Simulation results show that the fuel cell is a multitime-scale system; some of the cell output responses exhibit consecutive apparent dominant time constants, ranging from ∼0.2 ms to ∼40 s. They also reveal that the temperature and pressure of the inlet air stream and the temperature of the inlet fuel stream strongly affect the dynamics of the fuel cell system. The temperature of the inlet air stream has the strongest effect on the cell performance, and the effects of the inlet air and fuel velocities on the cell response are weaker than those of inlet feed pressures and temperatures. A simple control system is then implemented to control the fuel-cell outlet voltage and cell−tube temperature through manipulation of the pressure and temperature of the inlet air stream, respectively. The results show that the control system can successfully reject unmeasured step changes (disturbances) in the load resistance, the velocity of the inlet air stream, and the pressure, temperature, and velocity of the inlet fuel stream.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801555d

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6105–6111

Titre :	Dynamic modeling to minimize energy use for CO2 capture in power plants by aqueous monoethanolamine
Type de document :	texte imprimé
Auteurs :	Sepideh Ziaii, Auteur ; Gary T. Rochelle, Auteur ; Thomas F. Edgar, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6105–6111
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	CO2 capture Dynamic rate-based model Coal-fired power plants
Résumé :	A dynamic rate-based model was developed for stripping in CO2 capture from coal-fired power plants with 30 wt % monoethanolamine (MEA). The model, created in a flow sheet of Aspen Custom Modeler, was based on the film theory for liquid and vapor phases. It takes into account the impact of equilibrium reactions on the mass transfer, thermodynamic nonidealities, and the hydraulics of the structured packing. With this model, steady state analyses were carried out for the stripper to understand the effect of the lean loading and the height of the packing on total equivalent work and find optimum operating conditions that minimize power plant lost work. Two dynamic strategies with control configurations are proposed to run the stripper in a flexible operation during the period of electricity peak load and prices. Open loop responses demonstrated some differences in dynamic behavior and steady state values for proposed dynamic strategies. One of the approaches increased the CO2 removal by 1% at the reduced steam rate and provided faster response of the stripper to a step change in the reboiler heat rate.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801385q

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6098–6104

Titre :	Global optimization of gas lifting operations : a comparative study of piecewise linear formulations
Type de document :	texte imprimé
Auteurs :	Ruth Misener, Auteur ; Chrysanthos E. Gounaris, Auteur ; Christodoulos A. Floudas, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6098–6104
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Gas lifting Piecewise linearization techniques Oil field Scheduling
Résumé :	Continuous gas lifting is the process of increasing oil well production by injecting compressed natural gas, called “lift gas”, into the production tubing of an oil well [ Presented at the SPE Gas Technology Symposium, Calgary, Alberta, Canada, 1996]. This paper considers the problem of optimizing the distribution of a limited supply of lift gas to wells in an oil field using piecewise linearization techniques. Four modeling approaches, proposed by Nemhauser and Woolsey [ Integer and Combinatorial Optimization; J. Wiley: New York, 1988], Foudas [ Nonlinear and Mixed-Integer Optimization: Fundamentals and Applications; Oxford University Press: New York, 1995], Sherali [ Oper. Res. Lett. 2001, 28, 155.], and Keha et al. [ Oper. Res. Lett. 2004, 32, 44.], are presented and the gas lifting problem is solved using each method. Each of the four frameworks is sufficient to solve the problem to global optimality and the method presented by Keha et al. has the best computational performance. The gas lifting problem is used within the context of larger problems such as well scheduling in oil fields [ Comput. Chem. Eng. 2005, 29, 1523.], and this proposed work can be used to make one of the key parts of the well scheduling problem more efficient.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8012117

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6087–6097

Titre :	Dynamics and control of process networks with large energy recycle
Type de document :	texte imprimé
Auteurs :	Sujit S. Jogwar, Auteur ; Michael Baldea, Auteur ; Prodromos Daoutidis, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6087–6097
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Energy integrated networks Input/output energy flows
Résumé :	This paper focuses on the dynamics and control aspects of a class of energy integrated networks with large recycle of energy compared to the input/output energy flows. A prototype network is considered to identify the underlying model structure. A time scale separation in the energy dynamics of such networks is documented. Using singular perturbation techniques, a model reduction procedure is outlined, resulting in nonstiff reduced order models for the dynamics in each time scale. The theoretical results are illustrated with the help of examples and a simulation case study on a reactor-feed effluent heat exchanger network.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801050b

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6068–6086

Titre :	A review of solid oxide fuel cell (SOFC) dynamic models
Type de document :	texte imprimé
Auteurs :	Debangsu Bhattacharyya, Auteur ; Raghunathan Rengaswamy, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6068–6086
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	State-of-the-art dynamic models Solid oxide fuel cells Dynamic modeling
Résumé :	In this paper, state-of-the-art dynamic models for solid oxide fuel cells (SOFCs) in the open literature are reviewed. The review also includes the transient modeling of SOFC systems with reformers. In the transients of a SOFC, three characteristic time constants are observed. One of the challenges in transient modeling is to capture these characteristic times. The first characteristic time is on the order of milliseconds and is mostly neglected, because it is too small, from the viewpoint of practical applications. The second time constant is on the order of seconds and arises mainly because of the mass-transport dynamics. The third characteristic time is on the order of minutes or hours and is dependent on the energy transport characteristics of the system. These characteristic times are extremely system-specific and, therefore, must be identified on a case-to-case basis. In this paper, the existing literature on dynamic studies are reviewed, focusing mainly on the fidelity of the model that is required to capture these time constants. The dynamic modeling of SOFC is still not as rich as the steady-state modeling. Therefore, steady-state models are also reviewed, whenever required. The utility of the dynamic models in design, control, and operation is discussed. A dynamic model from the literature is chosen for this purpose.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801664j

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6059–6067

Titre :	Practical approach to design and implementation of a control algorithm in an artificial pancreatic beta cell
Type de document :	texte imprimé
Auteurs :	Matthew W. Percival, Auteur ; Dassau Eyal, Auteur ; Howard Zisser, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6059–6067
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Artificial pancreatic beta cell Control algorithm Glucose-insulin kinetics Hardware-in-the-loop implementation
Résumé :	The rate limiting bottleneck in the development of an artificial pancreatic beta cell is currently the control algorithm used to make insulin dosing decisions. In this paper, a solution for the rapid development of a personalized control algorithm was proposed and the methodology was tested on the pilot scale using a physiological model of glucose−insulin kinetics and a hardware-in-the-loop (HIL) implementation of an artificial pancreatic beta cell. A model-based controller was developed from the identification tests and was augmented with advanced control strategies. The resulting controller improved glycemia from the open-loop case with no hypoglycemic events and a reduction in time spent hyperglycemic. Robustness issues were addressed with a 50% mismatch in insulin sensitivity from model to plant. The HIL platform provided insight into the effects of sensor drift and practicalities of continuous insulin delivery based on glucose sensor feedback.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801432u

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6050–6058

Titre :	Scheduling of multistage batch processes under utility constraints
Type de document :	texte imprimé
Auteurs :	Arul Sundaramoorthy, Auteur ; Christos T. Maravelias, Auteur ; Pradeep Prasad, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6050–6058
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Mixed-integer programming formulation Multiproduct multistage processes Scheduling Simultaneous batching Storage vessels
Résumé :	We present a novel discrete-time mixed-integer programming (MIP) formulation for the simultaneous batching and scheduling in multiproduct multistage processes under utility constraints. In addition to processing units and storage vessels, we consider utilities such as cooling water, steam, and electricity that are available in limited quantities. Since different tasks often share the limited utilities at the same time, we use a common time-grid approach. Further, the proposed method handles the batching decisions (the number and sizes of batches) seamlessly without the usage of explicit batch-selection variables. To preserve batch identity in storage vessels, we introduce a new class of inventory variables and constraints. Our approach is the first to address limited utilities for simultaneous batching and scheduling in multistage processes.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801386m

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6034–6049

Titre :	New control structure for divided-wall columns
Type de document :	texte imprimé
Auteurs :	Hao Ling, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6034–6049
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Divided-wall column Ternary mixtures Steady-state design issues Heuristic design optimization method Rigorous design optimization method
Résumé :	Industrial applications of the divided-wall column for the separation of ternary mixtures have increased in recent years with about 40 columns reported to be in service. The divided-wall column is a practical way to implement the topology of the Petlyuk column that features two columns (a prefractionator into which the feed is introduced and a main column from which a sidestream product is withdrawn) with interconnected vapor and liquid streams arising from a single reboiler and a single condenser. Many papers discuss the steady-state design issues and propose heuristic and rigorous design optimization methods. The dynamic control of the divided-wall column has been explored in a relatively small number of papers. Control is more difficult than with a conventional two-column separation sequence because there is more interaction among controlled and manipulated variables since the four sections of the column are coupled. The vapor split is fixed at the design stage and cannot be changed during operation, but the liquid split can be manipulated to achieve some control objective. A number of control structures and algorithms have been proposed, but the reported results present a somewhat confusing picture. Different authors draw conflicting and inconsistent conclusions. Most papers control the purities of the three product streams using reflux flow rate, sidestream flow rate, and vapor boilup. This paper proposes a new control structure that controls these purities and also minimizes energy consumption. This is achieved implicitly by controlling a composition of the heaviest component in the prefractionator. Disturbances in feed flow rate and feed composition are used to demonstrate the effectiveness of the proposed control structure. A comparison of the dynamic controllability of the divided-wall column with a conventional configuration is also provided.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801373b

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6022–6033

Titre :	Modifier-adaptation methodology for real-time optimization
Type de document :	texte imprimé
Auteurs :	A. Marchetti, Auteur ; B. Chachuat, Auteur ; D. Bonvin, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6022–6033
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Real-time optimization scheme Necessary conditions of optimality (NCO) Plant-model mismatch
Résumé :	The ability of a model-based real-time optimization (RTO) scheme to converge to the plant optimum relies on the ability of the underlying process model to predict the plant’s necessary conditions of optimality (NCO). These include the values and gradients of the active constraints, as well as the gradient of the cost function. Hence, in the presence of plant−model mismatch or unmeasured disturbances, one could use (estimates of) the plant NCO to track the plant optimum. This paper shows how to formulate a modifed optimization problem that incorporates such information. The so-called modifiers, which express the difference between the measured or estimated plant NCO and those predicted by the model, are added to the constraints and the cost function of the modified optimization problem and are adapted iteratively. Local convergence and model-adequacy issues are analyzed. The modifier-adaptation scheme is tested experimentally via the RTO of a three-tank system.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801352x

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6010–6021

Titre :	Effect of thermodynamic restriction on energy cost optimization of RO membrane water desalination
Type de document :	texte imprimé
Auteurs :	Aihua Zhu, Auteur ; Panagiotis D. Christofides, Auteur ; Yoram Cohen, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6010–6021
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Reverse osmosis membranes Water production
Résumé :	Advances in highly permeable reverse osmosis (RO) membranes have enabled desalting operations, in which it is practically feasible for the applied pressure to approach the osmotic pressure of the exit brine stream. However, energy cost remains a major contributor to the total cost of water produced by RO membrane desalination. Reduction of the overall cost of water production represents a major challenge and, in the present work, various elements of water production cost are evaluated from the viewpoint of optimization, with respect to various costs (energy, membrane area and permeability, brine management, and pressure drop), as well as the important thermodynamic cross-flow constraint, utilization of energy recovery devices, and operational feed and permeate flow rate constraints. More specifically, in the present study, an approach to the optimization of product water recovery at pressures that approach the osmotic pressure of the exit brine stream is presented via several simple RO process models that utilize highly permeable membranes. The results suggest that it is indeed feasible to refine RO processes to target for operation under the condition of minimum energy consumption, while considering the constraint imposed by the osmotic pressure, as specified by the thermodynamic cross-flow restriction. Although it is shown that multistage RO provides energy savings, this is at the expense of greater membrane area cost. Overall, as process costs above energy costs are added, the operational point for achieving minimum water production cost shifts to higher recoveries. Although the newer generation of RO membranes can allow high recovery operations at lower pressures, limitations due to mineral scaling and fouling impose additional constraints. The incorporation of these phenomena in the optimization approach is the subject of ongoing research.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800735q

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6000–6009

Titre :	Parameter set selection via clustering of parameters into pairwise indistinguishable groups of parameters
Type de document :	texte imprimé
Auteurs :	Yunfei Chu, Auteur ; Juergen Hahn, Auteur
Année de publication :	2009
Article en page(s) :	pp. 6000–6009
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Parameter set Clustering Computational effort grows drastically
Résumé :	Selecting a set of parameters to be estimated from experimental data is an important problem with many different types of applications. However, the computational effort grows drastically with the number of parameters in the model. This paper proposes a technique that reduces the parameters that need to be considered by clustering, where the model parameters are put into different groups on the basis of the dynamic effect that changes have on the model output. The computational requirements of the parameter set selection problem then drastically reduces as only one parameter per cluster needs to be considered instead of each parameter in the model. This paper develops the underlying theory of the presented technique and also illustrates the method on a model of a signal transduction pathway with 115 parameters.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800432s

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 5992–5999

Titre :	Scaleup of Cu(InGa)Se2 thin-film coevaporative physical vapor deposition process, 2. Evaporation source design
Type de document :	texte imprimé
Auteurs :	Kapil Mukati, Auteur ; Babatunde A. Ogunnaike, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5992–5999
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Cu(InGa)Se2 thin film Coevaporative physical vapor deposition processes Three-dimensional thermal model Direct simulation Monte Carlo method
Résumé :	We recently presented the development and experimental validation of two models that are essential for effective commercial-scale source design for Cu(InGa)Se2 thin film coevaporative physical vapor deposition processes: a three-dimensional thermal model of the evaporation source, and a Direct Simulation Monte Carlo (DSMC)-method-based effusion model. We showed that these models can be used to obtain reasonably accurate melt temperature dynamics and nozzle effusion flow properties. We now present how these simulation tools are used to develop a scale-up methodology for the effective commercialization of the pilot-scale physical vapor deposition (PVD) process at the University of Delaware’s Institute of Energy Conversion (IEC). We illustrate the methodology using two commercial-scale source design studies: a three-nozzle single source and a four-nozzle modular source. We also show that the proposed source designs are robust to modeling errors and the important process parameter of the source-to-substrate distance.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801596a

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 5975–5991

Titre :	Scaleup of Cu(InGa)Se2 thin film coevaporative physical vapor deposition process, 1. Evaporation source model development
Type de document :	texte imprimé
Auteurs :	Kapil Mukati, Auteur ; Babatunde A. Ogunnaike, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5975–5991
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Cu(InGa)Se2 thin-film Scaleup Breakthroughs
Résumé :	Even though rapid advances have been made in improving Cu(InGa)Se2 thin-film-based solar cell efficiencies, the breakthroughs have been limited to the laboratory scale. Most commercially viable thin-film technologies reside at the premanufacturing development stage and scaleup has proven to be much more difficult than expected. Elemental in-line evaporation on flexible substrates in a roll-to-roll configuration is a commercially attractive process for the manufacture of large-area CuInSe2-based photovoltaics. At the University of Delaware’s Institute of Energy Conversion (IEC), such a process is being investigated, at the pilot scale, for a polyimide web substrate. The process works well for 6-in.-wide substrates and for short deposition runtimes. However, a commercially viable process is required to produce large-area, high-quality films at a much-higher throughput. Specifically, the desired film thickness (∼2 μm) and composition uniformity must be achieved continuously and reproducibly on large-area (12-in.-wide) substrates at translation speeds (∼1 ft/min) much higher than those currently used in pilot-scale processes. Although achievement of the desired film thickness and composition setpoints is best addressed by proper control system design, the film thickness uniformity is determined by the source design and individual nozzle effusion rates. The nozzle effusion rates, in turn, are dependent on the melt surface temperature profile and, thus, on the source design itself. Therefore, proper source design is critical in achieving film thickness uniformity. We have identified two modeling requirements for effective thermal evaporation source design: (i) a detailed three-dimensional thermal model of the evaporation source, to predict the melt surface temperature accurately, and (ii) a nozzle effusion model, to predict the effusion rate and the vapor flux distribution for a given nozzle geometry (length and diameter), melt surface temperature, and evaporant. To meet the first requirement, we have developed a first-principles three-dimensional electrothermal model using COMSOL Multiphysics software; the Direct Simulation Monte Carlo (DSMC) method has been used for effusion modeling. In this paper, which is the first of a two-part series, we present the details of the two models and their experimental validation.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8015957

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 5969–5974

Titre :	Particle dynamics in a chemical vapor deposition reactor : a multiscale approach
Type de document :	texte imprimé
Auteurs :	Yousef Ashrafi, Auteur ; Luke Achenie, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5969–5974
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Zinc sulfide Chemical vapor deposition method Deposited film
Résumé :	Compared to other semiconductors, zinc sulfide has a large direct band gap which makes it useful in a broad range of optical applications which demand high quality zinc sulfide films which are produced through the chemical vapor deposition method. In order to achieve high quality films with low defects, a better understanding of the deposition process is necessary. A common cause of defects in the deposited film is due to the fact that the morphology of adducts in the gas phase is different from that of the deposited film. These adducts affect the deposition efficiency and film quality. This paper strives to understand the impact of adducts through a multiscale modeling approach which is used to explain the possible link between the cluster size and the morphological defects on the deposited film. This understanding can be used within a simulation framework to optimize reaction conditions that minimize film defects.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8015522

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 5962–5968

Titre :	Controlling homogeneous chemistry in homogeneous-heterogeneous reactors : application to propane combustion
Type de document :	texte imprimé
Auteurs :	Georgios D. Stefanidis, Auteur ; Dionisios G. Vlachos, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5962–5968
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Homogeneous chemistry Homogeneous-heterogeneous reactors Two-dimensional computational fluid dynamics model
Résumé :	Operation strategies for controlling the extent of homogeneous chemistry in homogeneous−heterogeneous (HH) reactors were developed for a catalytic plate microreactor using a two-dimensional computational fluid dynamics model for propane combustion on Pt as our prototype system. The effect of the reactor gap size (distance between plates) was analyzed. We found that homogeneous chemistry is sustained for gaps well below the quenching diameter as a result of enhanced catalyst-induced heating. This finding has important ramifications for catalyst lifetime and safety and could be used to produce chemicals, for example, in oxidative dehydrogenation and oxidative coupling reactions. The homogeneous chemistry contribution decreases with decreasing gap size. Catalytic chemistry alone can occur under suitable flow rates, compositions, and heat loss/heat exchange rates. The synergism or competition between homogeneous and catalytic chemistries is delineated.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801480m

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 5954–5961

Titre :	Microreactor for high-yield chemical bath deposition of semiconductor nanowires : ZnO Nanowire case study
Type de document :	texte imprimé
Auteurs :	Kevin M. McPeak, Auteur ; Jason B. Baxter, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5954–5961
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Microreactor ZnO nanowire deposition
Résumé :	We report on the design of a batch microreactor for depositing oxide and chalcogenide nanowires and thin films onto a substrate from solution, and we demonstrate its utility using ZnO nanowire deposition as a case study. A contact-heated substrate forms one wall of a submillimeter reaction channel, and the short mass-transport length results in high-yield deposition on the substrate with minimal loss to precipitation or deposition on other unheated reactor walls. The microreactor’s low thermal mass enables rapid heating, which reduces the induction time and increases the deposition rate. The microreactor was used to grow dense arrays of well-aligned single-crystal ZnO nanowires with diameters of 80−100 nm and yields of 35%−50%. Deposition rates are faster, yields are an order of magnitude higher, and ZnO defect densities are equivalent to those using a conventional chemical bath deposition reactor with the same chemistry. The species that limit deposition rates are identified.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801405d

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 5943–5953

Titre :	Promoter-induced morphological changes of Ag catalysts for ethylene epoxidation
Type de document :	texte imprimé
Auteurs :	Joseph C. Dellamorte, Auteur ; Jochen Lauterbach, Auteur ; Mark A. Barteau, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5943–5953
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Ag catalysts Scanning electron microscopy analysis High-throughput reactor experiments
Résumé :	The combination of high-throughput reactor experiments and scanning electron microscopy analysis of promoted Ag catalysts provides critical insights into mechanistic and morphological changes. In particular, catalysts promoted with Cu, Cd, Au, Pt, and Re were analyzed to understand the morphological effects of these promoters on the Ag particles. Cu increases the sintering of Ag particles, while Cd and Re were found to alter the Ag particle sizes into a trimodal distribution. However, contrasting effects of Re and Cd were found on the catalyst activity. Cd−Ag catalysts exhibited a 5-fold increase in the ethylene conversion for a variety of Cd loadings, compared to unpromoted Ag. Moderate increases in conversion and selectivity were seen with the addition of 25 ppm Re, while further Re impregnation led to decreases in ethylene conversion and ethylene oxide selectivity. Au and Pt block surface Ag sites by nucleating as separate particles on the silver surface. In doing so, they reduce the activity of the catalyst, but also reduce the sintering of the Ag particles.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801627k

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 5934–5942

Titre :	Enhanced kinetics of CO2 hydrate formation under static conditions
Type de document :	texte imprimé
Auteurs :	Junshe Zhang, Auteur ; Jae W. Lee, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5934–5942
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	CO2 hydrate formation Cyclopentane Nonstirred batch reactor
Résumé :	Trapping CO2 in hydrates is one of the new technologies for CO2 capture and storage. One of the primary obstacles to this option is the low formation rate. This work presents the rapid formation of CO2 hydrates with a small amount of cyclopentane (CP). The formation kinetics was investigated in a 474 cm3 nonstirred batch reactor with 100 and 200 cm3 of water. At volume ratios of CP to water between 0.01 and 0.1, the maximum growth rate is 0.32 mol h−1 at CO2 pressures ranging from 1.9 to 3.4 MPa and at 274 K. CO2 hydrates (sI) and CO2 + CP (sII) binary hydrates coexist at the end of hydrate growth. The mole ratio of CO2 entrapped in the sI hydrates to that in the sII binary hydrates is higher with 100 cm3 of water than with 200 cm3 of water. The same trend is also observed for the total amount of CO2 entrapped in the hydrate phase. The growth rate depends not only on the water volume but also on the pressure. The hydrate growth rate and the water conversion reach a maximum at 3.06 MPa and then decrease as the pressure increases from 1.9 to 3.4 MPa with 100 cm3 of water and 5 cm3 of CP. The water conversion to the hydrates reaches 52% within 2 h. This accelerated formation kinetics can provide a stepping-stone for developing a new hydrate-based CO2 capture and storage technique.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801170u

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 5923–5933

Titre :	roll-to-roll deposition of a semiconductor film on a flexible substrate for photovoltaics : conception to reality
Type de document :	texte imprimé
Auteurs :	Gregory M. Hanket, Auteur ; Robert W. Birkmire, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5923–5933
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	T. W. Fraser Russell Photovoltaic technology Thin-film deposition processes
Résumé :	T. W. Fraser Russell has made significant contributions to process engineering advances relating to the commercialization of photovoltaic technology. He recognized that its commercial viability would require the application of sound chemical engineering principles to solve a very nontraditional chemical engineering problem—in particular the engineering methodologies needed to transfer thin-film deposition processes from the laboratory scale into commercial production. In this paper, a historical narrative, spanning the late 1970s through the present day, is presented detailing Fraser’s contributions to the development of photovoltaic film deposition on a continuous moving web via thermal evaporation.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801659j

Industrial & engineering chemistry research / Paul, Donald R. . Vol. 48 N° 13

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