Catalogue en ligne Bibliothèque Ecole Nationale Polytechnique d'Alger

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4444–4451

Titre :	Performance of four axial flow impellers for agitation of pulp suspensions in a laboratory - scale cylindrical stock chest
Type de document :	texte imprimé
Auteurs :	Manish R. Bhole, Auteur ; Chad P. J. Bennington, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4444–4451
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Axial flow
Résumé :	Axial flow impellers are commonly used for pulp suspension agitation. Pulp fiber suspensions are non-Newtonian and exhibit a yield stress. In mixing operations, a ‘cavern’ (region of active motion) is created around the impeller, with the size of the cavern affecting the quality of mixing attained. In this work, the cavern size produced by four different axial flow impellers in a Cm = 3% (mass concentration) hardwood pulp suspension was measured using electrical resistance tomography (ERT) and by analysis of dynamic mixing tests. Cavern size is shown to depend on impeller performance as characterized by power number, NP, and axial force number, Nf. At an equal power consumption of 0.53 kW/m3 the largest cavern was produced by the impeller having the largest values of NP and Nf. The measured cavern volumes compared well with predictions of the axial force model developed by Hui et al. [Hui, L. K.; Bennington, C. P. J.; Dumont, G. A. Cavern formation in pulp suspensions using side-entering axial-flow impellers. Chem. Eng. Sci. 2009, 64, 509], which accounted for interaction between the cavern and the vessel walls. When the cavern just filled the vessel volume, the time constants determined using the dynamic mixing test data reached 90% of their theoretical values (with the estimated standard deviation of ±10%), indicating that the chest approached an ideal dynamic response (complete mixing) with the onset of complete motion in the chest.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901854d

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4436–4443

Titre :	Water cleaning of biodiesel. effect of catalyst concentration, water amount, and washing temperature on biodiesel obtained from rapeseed oil and used oil
Type de document :	texte imprimé
Auteurs :	Alberto Gonzalo, Auteur ; Manuel García, Auteur ; José Luis Sanchez, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4436–4443
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Biodiesel Catalyst
Résumé :	The effect of changing the NaOH wt % (0.7−0.9%) in the transesterification, the amount of water (30−90 wt % of the biodiesel), and the temperature (40−60 °C) in the water cleaning step of biodiesel has been investigated, specifically the influence of these factors on some properties (acidity, viscosity and density) and contaminants (methanol, Na, glycerine, water, and glycerides) of the resulting biodiesel produced from two different oils (rapeseed and used frying oil) using a three factor-two level experimental design, and statistical analysis by ANOVA of the results. The biodiesels produced from both oils show very similar trends: methanol, sodium, and glycerine are almost completely removed from the biodiesel phase in one single step, whereas the glycerides content is not affected by the washing conditions. Viscosity and density are only very slightly affected by the washing step. The water content of the biodiesel is affected by both the water amount used and the temperature in an inverse way: the higher the temperature and the lower the water amount used in the cleaning step, the higher the water content in biodiesel. This washing step was also simulated in Aspen HYSYS V7.0 software. Using the NRTL thermodynamic package for properties calculation, the results obtained showed a reasonable agreement with experimental ones, although it should be improved for a better calculation of biodiesel final properties.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901707q

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4426–4435

Titre :	Study of solid − liquid mixing in agitated tanks through computational fluid dynamics modeling
Type de document :	texte imprimé
Auteurs :	Seyed Hosseini, Auteur ; Dineshkumar Patel, Auteur ; Farhad Ein-Mozaffari, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4426–4435
Note générale :	Industrial chemisty
Langues :	Anglais (eng)
Mots-clés :	Fluid Dynamics
Résumé :	Solid−liquid mixing is one of the most important mixing operations due to its vast applications in many unit operations such as crystallization, adsorption, solid-catalyzed reaction, suspension polymerization, and activated sludge processes. In this study, a computational fluid dynamics (CFD) model was developed for solid−liquid mixing in a cylindrical tank equipped with a top-entering impeller to investigate the effect of impeller type (Lightnin A100, A200, and A310), impeller off-bottom clearance (T/6−T/2, where T is tank diameter), impeller speed (150−800 rpm), particle size (100−900 μm), and particle specific gravity (1.4−6) on the mixing quality. An Eulerian−Eulerian (EE) approach, standard k−ε model, and multiple reference frames (MRF) techniques were employed to simulate the two-phase flow, turbulent flow, and impeller rotation, respectively. The impeller torque, cloud height, and just suspended impeller speed (Njs) computed by the CFD model agreed well with the experimental data. The validated CFD model was then employed to calculate the solid concentration profiles by which the degree of homogeneity was quantified as a function of operating conditions and design parameters.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901130z

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4420-4425

Titre :	Density prediction of ionic liquids at different temperatures and pressures using a group contribution equation of state based on electrolyte perturbation theory
Type de document :	texte imprimé
Auteurs :	Junfeng Wang, Auteur ; Zhibao Li, Auteur ; Chunxi Li, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4420-4425
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Thermodynamic properties Perturbation theory Electrolyte Equations of state Ionic liquid Prediction Density
Résumé :	Based on the electrolyte perturbation theory, a group contribution equation of state that embodies hard-sphere repulsion, dispersive attraction, and ionic electrostatic interaction energy was established to calculate the density of ionic liquids (ILs). According to this method, each ionic liquid is divided into several groups representing cation, anion, and alkyl substituents. The performance of the model was examined by describing the densities of a large number of imidazolium-based ILs over a wide range of temperatures (293.15―414.15 K) and pressures (0.1-70.43 MPa). A total number of 202 data points of density for 12 ILs and 2 molecular liquids (i.e., I-methylimidazole and 1-ethylimidazole) were used to fit the group parameters, namely, the soft-core diameter σ and the dispersive energy e. The resulting group parameters were used to predict 961 data points of density for 29 ILs at varying temperatures and pressures. The model was found to estimate well the densities of ionic liquids with an overall average relative deviation (ARD) of 0.41% for correlation and an ARD of 0.63% for prediction, which demonstrates the applicability of the model and the rationality of the soft-core diameter and dispersive energy parameters.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=22732930

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4412-4419

Titre :	Chemical equilibrium conversion of the tert - amyl - methyl - ether synthesis in the presence of n - pentane, tetrahydrofuran, or benzene
Type de document :	texte imprimé
Auteurs :	Vincent Liebert, Auteur ; Torben Hector, Auteur ; Jürgen Gmehling, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4412-4419
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Chemical equilibrium
Résumé :	The chemical equilibrium conversion of the reversible liquid-phase etherification of isoamylene with methanol to tert-amyl-methyl-ether using Amberlyst 36 as catalyst was investigated in a temperature range from 312.15 to 354.15 K. The experiments were also carried out in the presence of n-pentane, tetrahydrofuran, or benzene to investigate the influence of different inert solvents on the equilibrium conversion. From the results the standard enthalpy and standard Gibbs energy of reaction have been determined. The experimental conversions have been compared with the predicted conversions assuming ideal and nonideal behavior. For the predictions, tabulated standard thermodynamic properties at 298.15 in the ideal gas state (ΔHf0, ΔGf0), vapor pressures Pis, and standard molar heat capacities cp0 in the liquid phase have been used. The required activity coefficients were calculated with the help of the Wilson model or predicted using the group-contribution method modified UNIFAC (Dortmund).
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=22732929

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp 4405–4411

Titre :	Biosorption of lanthanum, cerium, europium, and ytterbium by a brown marine alga, turbinaria conoides
Type de document :	texte imprimé
Auteurs :	K. Vijayaraghavan, Auteur ; M. Sathishkumar, Auteur ; R. Balasubramanian, Auteur
Année de publication :	2010
Article en page(s) :	pp 4405–4411
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Biosorption
Résumé :	The ability of a brown marine alga, Turbinaria conoides, to remove four rare-earth elements (REEs; lanthanum, cerium, europium, and ytterbium) was evaluated. Results showed that T. conoides was an excellent biosorbent for all four REEs. The equilibrium pH was found to severely affect the biosorption performance; pH 4.9 ± 0.2 was found to be an optimum pH for favorable biosorption of REEs. The biosorption mechanism was found to proceed mainly by ion-exchange reactions between the lanthanide ions and the carboxyl groups present on the algal surface, confirmed by the pH edge, desorption, and scanning electron microscopy/energy-dispersive X-ray results. Biosorption isotherms were modeled using the Langmuir, Freundlich, and Toth isotherms, with the latter-described REE isotherms with very high correlation coefficients and lower error values. Maximum biosorption uptakes, according to the Langmuir model, were recorded as 154.7, 152.8, 138.2, and 121.2 mg/g for La, Ce, Eu, and Yb, respectively. Biosorption kinetics of REEs was found to be rapid, achieving 90% of total biosorption within 50 min. Desorption was successful with 0.05 M HCl, and the biomass was regenerated and reused for three sorption−desorption cycles without a significant loss in the biosorption capacity.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie1000373

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4399–4404

Titre :	High - Flux SAPO - 34 membrane for CO2 / N2 separation
Type de document :	texte imprimé
Auteurs :	Li, Shiguang, Auteur ; Chinbay Q. Fan, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4399–4404
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Carbon dioxide
Résumé :	SAPO-34 membranes, synthesized by using multiple templates and reduced crystallization time, showed high CO2 permeability for separating CO2/N2 mixtures up to 230 °C. At a trans-membrane pressure drop of 138 kPa and an atmospheric pressure in the permeate side, one such membrane had a CO2 permeance of 1.2 × 10−6 mol/m2·s·Pa (= 3500 GPU) with a CO2/N2 separation selectivity of 32 for a 50/50 feed at 22 °C. At a feed pressure of 2.3 MPa (23 bar), the CO2 flux was as high as 75 kg/m2 h. The CO2/N2 separations were also investigated in part by using vacuum permeate pumping, where the membrane showed a CO2 permeance of 7.7 × 10−7 mol/m2·s·Pa and a CO2 permeate concentration of 93% for an equimolar feed at 22 °C. At 105 °C, adding 8% water vapor to the feed had almost no effect on the CO2/N2 separation selectivity. The CO2 permeance decreased by 37%, but it was recovered by calcination.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=22732927

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp 4383–4398

Titre :	“Profile method” for the measurement of kLa and kVa in distillation columns. validation of rate - based distillation models using concentration profiles measured along the column
Type de document :	texte imprimé
Auteurs :	F. J. Rejl, Auteur ; L. Valenz, Auteur ; V. Linek, Auteur
Année de publication :	2010
Article en page(s) :	pp 4383–4398
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Distillation Columns
Résumé :	The “profile method” enables the determination of vapor- and liquid-side volumetric mass-transfer coefficients kVa and kLa by comparing the concentration profiles measured in both phases in a distillation column with the simulated profiles. The method is based on the fact that the shape of the concentration profiles along the column depend significantly on the distribution of the mass-transfer resistance between the liquid and vapor phases. This makes it possible to measure kLa and kVa directly in the distillation columns, in the same manner that is possible in absorption columns, and therefore to validate the distillation models more conclusively than by means of comparing the experimental and calculated height equivalent to a theoretical plate values. The coefficients were measured on structured packing Mellapak250Y. A small axial mixing of phases on this type of packing enables the use of a plug-flow model for both phases. Three distillation systems, methanol−ethanol, ethanol−propanol, and methanol−propanol, were used under total reflux and atmospheric pressure. Samples of the phases were withdrawn directly from the column packing by means of special sampling devices. The dependence of the individual transport coefficients on the phase flow rate was obtained by changing the reboiler duty. The dependencies were compared with those predicted by the following three mass-transfer correlations developed for packed columns: RBF (Rocha et al. Ind. Eng. Chem. Res. 1996, 35, 1660), BS (Billet, R.; Schultes, M. Trans. Inst. Chem. Eng. 1999, 77, 498), and DELFT (Olujic et al. Chem. Eng. Proc. 1999, 38, 683). The coefficients obtained by the profile method differ substantially from those calculated from the original models. Specifically, all of the original models considerably overvalue the kLa coefficients (RBF by up to 2 times, BS by up to 1.5 times, and DELFT by up to 6.3 times) and undervalue the kVa coefficients (all by up to 2 times). The dependence of the mass-transfer coefficients on the rate of the phases predicted by any of the original models is not consistent with that of the profile method. It has also been shown that the experimental concentration profiles strongly differ from the profiles calculated from the Aspen Plus simulation program. The correlations of the kLa and kVa coefficients with improved flow dependencies according to the profile method are presented. The concentration profiles calculated from the improved correlations fit the profiles accurately.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901690m

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4377–4382

Titre :	Study on production of CH4 in hydrogen purification with palladium − silver / ceramic composite membranes
Type de document :	texte imprimé
Auteurs :	Yang Li, Auteur ; BingJia Yao, Auteur ; Tomonori Takahashi, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4377–4382
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Hydrogen composite membranes
Résumé :	Hydrogen was purified by a series of Pd−Ag/ceramic composite membranes with different Pd−Ag alloy thickness ranging from 2.5 to 15 μm. During the process, methane (CH4) was found to be formed in the permeated gas, which was also reported in related studies. A comprehensive study was carried out to identify the source of CH4 by discussing the influence of membrane defect and feed composition with several gas mixtures as feed gas. It was found that CH4 content in the purified hydrogen increased with the defect degree, and for obtaining 99.9% permeated hydrogen, the helium leakage of the membrane should be less than 0.01 mL min−1 cm−2; whereas no helium flow should be detected, that is, the membranes should be completely defect-free, to achieve 99.999+% hydrogen. Meanwhile, different feed gases were used to discover the reason for production of CH4 during purification; the results revealed that only CO in the feed gas resulted in the formation of CH4 on the permeated side. Finally, on the basis of the above findings, a small amount of Au in the Pd−Ag alloy was added to examine the possibility of preventing CH4 formation, and the preliminary result was satisfactory.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900624v

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4372–4376

Titre :	Desulfurization of low sulfur diesel by adsorption using activated carbon : adsorption isotherms
Type de document :	texte imprimé
Auteurs :	Celia Marin-Rosas, Auteur ; Luis F. Ramirez-Verduzco, Auteur ; Florentino R. Murrieta-Guevara, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4372–4376
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Adsorption Carbon Isotherms
Résumé :	Adsorptive desulfurization was studied using diesel fuel with low sulfur content (72 ppmw) and four commercial activated carbons (CAA, CAB, CAC, and CAD). After the adsorption scheme, it was possible to obtain a diesel with 15 ppmw of sulfur content. The experiments were carried out in a batch system at 303.15 K, atmospheric pressure, and 5−200 g-A/L-D, with magnetic stirring over 18 h. The adsorption isotherms were correlated by the Freundlich, Langmuir, Sips and Brunauer−Emmett−Teller (BET) models. There was a good agreement between the experimental and calculated adsorption isotherms. The Sips and BET models give the best correlation for the experiment.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901756b

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4360–4371

Titre :	Dynamic simulation and optimization for the start - up operation of an ethylene oxide plant
Type de document :	texte imprimé
Auteurs :	Xiongtao Yang, Auteur ; Qiang Xu, Auteur ; Kuyen Li, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4360–4371
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Ethylene Oxide
Résumé :	Ethylene oxide (EO) is an important chemical intermediate for the production of various chemical products. The manufacturing of EO involves critical exothermic reactions at high temperature and high pressure, whose failure may cause catastrophic personal injury, severe air pollution, and tremendous economic loss. Thus, an EO plant must be well controlled under various situations, especially during its start-up operations. In this paper, a general methodology for improving chemical plant start-up operations through plant-wide dynamic simulation has been developed. It undergoes modeling and validations for steady-state, dynamic, and historian start-up operations. On the basis of the validated dynamic simulation model, the original plant start-up strategy is further examined and optimized to speed-up the plant start-up operation with enhanced safety considerations. A case study on an EO plant start-up has demonstrated the significant operational and economic benefits of the proposed methodology.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9019038

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4352–4359

Titre :	Local modeling approach for spatially distributed system based on interval type - 2 T - S fuzzy sets
Type de document :	texte imprimé
Auteurs :	Mengling Wang, Auteur ; Ning Li, Auteur ; Shaoyuan Li, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4352–4359
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Spatial dynamics
Résumé :	It is important to choose the appropriate type of local model to reduce the model error for a spatially distributed system (SDS) under large uncertainties. In this paper, a new local modeling approach is proposed to estimate the spatial dynamics of SDS based on input output data. The interval type-2 T-S fuzzy model is developed to the local dynamics in consideration of the mutual influence of neighbor regions. The parameters and the proper fuzzy rules of the local models are obtained by using interval type-2 fuzzy satisfactory clustering algorithm. Then the global models can be determined by constructing the local models by smooth interpolation. The accuracies of the modeling methodologies are tested in the shell and tube heat exchanger.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901278r

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4340–4351

Titre :	On the degeneracy of the water/wastewater allocation problem in process plants
Type de document :	texte imprimé
Auteurs :	Debora C. Faria, Auteur ; Miguel J. Bagajewicz, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4340–4351
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Wastewater Process Plants
Résumé :	Several methodologies to design water systems in process plants are based on minimizing freshwater consumption. The objective is the appropriate one when water is scarce and costs are not a big issue. It has also been used as a substitute for cost in the belief that water and final treatment costs overwhelm other fixed capital and operating costs of regeneration processes. Among graphical and algorithmic methods, the popular “Pinch Technology”-based procedure has early proponents and contemporary advocates who consider and defend it as a good method to provide “insights” into the right answer. In this paper, we show that the minimum freshwater problem has sometimes a large number of alternative degenerate solutions, something that graphical and algorithmic procedures like the aforementioned pinch technology can hardly identify systematically. The fact that the degenerate solutions are many makes it worse. We provide a mathematical programming method to identify these solutions and to point out those that make more economical sense. We also provide means to identify suboptimal solutions that are very close to the optimum one. We illustrate these degeneracies in several cases of single and multiple contaminants.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901574g

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4329-4339

Titre :	Optimization of preventive maintenance in chemical process plants
Type de document :	texte imprimé
Auteurs :	DuyQuang Nguyen, Auteur ; Miguel Bagajewicz, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4329-4339
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Preventive maintenance Optimization
Résumé :	In this article, we use a genetic algorithm to obtain an economically optimal preventive maintenance frequency for different equipment, the parts inventory policy (number and type of spare parts to keep in stock), and labor allocation in process plants. To assess cost, we improved a previously published Monte Carlo simulation-based maintenance model (Nguyen et al. Ind. Eng. Chem. Res. 2008, 47(6), 1910−1924). Two examples, a Tennessee Eastman example and a fluid catalytic cracking unit in a refinery, are provided.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=22732920

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4308–4328

Titre :	Sequential approach to design batch distillation processes for homogeneous azeotropic systems
Type de document :	texte imprimé
Auteurs :	Vincentius Surya Kurnia Adi, Auteur ; Chuei-Tin Chang, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4308–4328
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Azeotropic Systems
Résumé :	By addressing both flowsheeting and scheduling issues, a systematic approach is developed in this work to design batch azeotropic distillation processes for the homogeneous ternary and quaternary systems. The proposed design strategy is implemented sequentially in three stages. First, an integer program (IP) is formulated for producing the optimal structure of state-task network (STN). A nonlinear program (NLP) is then developed to generate the corresponding material-balance constraints. In the final step, a mixed integer linear programming (MILP) model and a mixed integer nonlinear programming (MINLP) model are constructed for stipulating the optimal short-term and cyclic schedules respectively. The conventional concept of event points is adopted to facilitate the continuous-time representation in these model formulations. The implementation procedure is illustrated with two example systems in this paper. Satisfactory process configurations and production schedules can both be produced in all the cases we have studied so far.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie100101w

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp.4297–4307

Titre :	Design and control of a reactive distillation column based on a nonlinear wave propagation theory : production of terephthalic acid
Type de document :	texte imprimé
Auteurs :	Bo-kyung Kim, Auteur ; Hwidong Hwang, Auteur ; Daesik Woo, Auteur
Année de publication :	2010
Article en page(s) :	pp.4297–4307
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Production Wave propagation Distillation with reaction Design
Résumé :	This paper is concerned with the design and control of a reactive distillation column for the synthesis of terephthalic acid (TPA) from dimethyl terephthalate (DMT). Both components are possible monomers for the production of fresh polyesters. The potential of reactive distillation for the hydrolysis of DMT was investigated, and the effects of the design parameters on the performances of the process were explored. A steady-state design and the dynamic behavior of the reactive distillation process were analyzed based on a nonlinear wave theory. Keeping the location of the column composition profile at the proper location was found to make the reaction zone active in the reactive distillation column, leading to a higher TPA yield. The proposed control scheme demonstrated excellent control of the reaction yield and product purity.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=22732918

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4285–4296

Titre :	Safe - parking framework for fault - tolerant control of transport − reaction processes
Type de document :	texte imprimé
Auteurs :	Maaz Mahmood, Auteur ; Prashant Mhaskar, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4285–4296
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Transport Reaction Processes
Résumé :	This work considers the problem of handling actuator faults in transport−reaction processes described by quasi-linear parabolic partial differential equations (PDEs) subject to input constraints. To this end, first, by exploiting the separation between the fast and slow eigenmodes of the parabolic spatial differential operator in combination with Galerkin’s method, a finite set of ordinary differential equations (ODEs) that captures the dominant dynamics of the PDE system are constructed. This finite ODE system is used to develop a Lyapunov-based model predictive controller which provides an explicit characterization of the set of initial conditions from where closed-loop stability of the parabolic PDE system is guaranteed. This control design is then subsequently used to develop a safe-parking framework for handling faults. In particular, faults which preclude the possibility of maintaining operation at the nominal equilibrium distribution, using the existing robust or reconfiguration-based fault-tolerant control approaches are considered. The key idea is to temporarily maintain the process at an appropriate “safe-park” distribution using the available depleted control action. This “safe-park” distribution is chosen to prevent onset of hazardous situations as well as to ensure smooth resumption of nominal operation upon fault repair. Utilizing the stability region characterization provided by the developed predictive controller, safe-park distributions from the safe-park candidates (equilibrium distributions subject to the remaining functioning and fail-safe values of the failed actuators) are chosen to preserve closed-loop stability upon fault repair. The proposed framework is illustrated on a diffusion−reaction process.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901295x

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4269–4284

Titre :	Understanding the impact of operating pressure on process intensification in reactive distillation columns
Type de document :	texte imprimé
Auteurs :	Shaofeng Wang, Auteur ; Kejin Huang, Auteur ; Quanquan Lin, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4269–4284
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Reactive distillation column
Résumé :	For a reactive distillation column involving reactions with high thermal effect, process intensification can be reinforced with the prudent adjustment of operating pressure within its feasible region bounded by the given hot and cold utilities. Three specific situations can be identified and should be dealt with cautiously during process synthesis and design. For a reactive distillation column involving reversible endothermic reactions, the enhancement of the operating pressure increases reactant conversion and reaction heat load, thus facilitating process intensification between the reaction operation and the separation operation involved. For a reactive distillation column involving equilibrium-limited exothermic reactions, the abatement of operating pressure increases reactant conversion and the reaction heat load, thus reinforcing process intensification between the reaction operation and the separation operation involved. For a reactive distillation column involving kinetically controlled exothermic reactions, the complicated relationship between operating pressure and reactant conversion and reaction heat load must be dealt with carefully, thus being likely to benefit process intensification between the reaction operation and the separation operation involved. Six hypothetical ideal and two real reactive distillation systems involving either equilibrium-limited or kinetically controlled reactions with high thermal effect are studied to evaluate the proposed philosophy. It has been found that with the appropriate selection of operating pressure, a considerable reduction of utility consumption can be secured beside a possible abatement in capital investment. These striking results evidence the strong necessity of deepening process intensification through the adjustment of operating pressure in the synthesis and design of reactive distillation columns involving reactions with high thermal effect.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie100067z

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4249–4268

Titre :	Petri - net based approach to configure online fault diagnosis systems for batch processes
Type de document :	texte imprimé
Auteurs :	Yi-Chung Chen, Auteur ; Ming-Li Yeh, Auteur ; Chia-Lun Hong, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4249–4268
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Batch Processes
Résumé :	Online fault diagnosis is a task of critical importance for maintaining a high level of operational safety in many chemical plants. The Petri-net models are adopted in this work for describing the fault propagation behaviors in batch processes. A systematic method has been developed to synthesize a timed Petri-net hierarchically structured according to any given piping and instrumentation diagram (P&ID) and its operating procedure. On the basis of this model, a diagnoser can be constructed automatically with a computer program for online implementation. Computer algorithms have also been devised to place additional sensors and/or synthesize extra operation steps for the purpose of improving diagnostic performance. Several examples are presented in this paper to demonstrate the effectiveness and correctness of the proposed approach.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901410p

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4230–4248

Titre :	Design and planning of sustainable industrial networks : application to a recovery network of residual products
Type de document :	texte imprimé
Auteurs :	Joaquim Duque, Auteur ; Ana Paula F. D. Barbosa-Povoa, Auteur ; Augusto Q. Novais, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4230–4248
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Industrial Networks
Résumé :	The present work describes the integration of environmental impact/damage evaluation into an optimization model for management of industrial networks. The selected methodology of environmental evaluation, the Eco-indicator 99, is based on the life cycle impact assessment. Its implementation and suitability is studied with an emphasis being placed on the strengths and limits of the methodology. The final model, derived from the application of process system engineering methodologies, is described as a mixed-integer linear program, which, once solved, is able to suggest the optimal processing and transportation routes, while optimizing a given objective function that either meets the design and environmental constraints or minimizes the eco-indicator. Whenever the impacts/damages costs are quantifiable, the calculation may also contemplate the inclusion of the environmental costs into the economic function that evaluates the network characteristic data and costs. An example based on the implementation of an innovative network for the recovery of the sludge obtained from aluminum surface finishing plants is presented. This illustrates the importance of including environmental impact/damage methodologies, explores their possible uses and analyzes obtained results. It is also used to perform a multiobjective analysis through an approximation to the Pareto curve for an economic-environmental trade-off. This curve is obtained through the application of a ε-constraint method, by plotting a set of successive optimized solutions given by the maximization of an economic function that reflects the costs of disposal, processing, transport, and materials storage versus an impact indicator obtained from the environment pollutants emitted. This analysis is complemented with the minimization of the eco-indicator value (EI99), along with an estimate of the corresponding amount of sludge recovery.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900940h

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4210–4229

Titre :	Diagnosis of poor control loop performance due to model − plant mismatch
Type de document :	texte imprimé
Auteurs :	S. Selvanathan, Auteur ; A. K. Tangirala, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4210–4229
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Model plant mismatch
Résumé :	Model−plant mismatch is a crucial factor that influences the performance of a closed-loop system. A new approach is proposed for the diagnosis of poor control loop performance due to model−plant mismatch (MPM) in the internal model control framework. In particular, the objective is to identify the mismatch in specific components of a transfer function model, namely, the gain, time-constant, and delay from closed-loop operating data. A new quantity Gp/Gm, called the plant model ratio (PMR) in the frequency domain is introduced as a measure of model−plant mismatch. It is shown that there exists a unique signature in PMR for each combination of mismatch in model parameters, which is the key step in the proposed method. A method to estimate the PMR from closed-loop operating data is provided. Theoretical and practical aspects of the mapping between the type of MPM and the proposed PMR are presented. Simulation studies demonstrate the effectiveness of the proposed method.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900769v

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4197-4209

Titre :	Prior checking and moving horizon smoothing for improved particle filtering
Type de document :	texte imprimé
Auteurs :	Lixin Lang, Auteur ; Prem K. Goel, Auteur ; Bhavik R. Bakshi, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4197-4209
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Smoothing Surveillance
Résumé :	Particle filtering, also known as sequential Monte Carlo (SMC) sampling, has been successfully applied to general state-space models for Bayesian inference. Being a simulation method, its performance relies to some extent on the generated samples or particles. For a poor initial guess a large fraction of particles is usually less representative of the underlying state's distribution and could even cause SMC to diverge. In this paper, an intuitive statistic, predictive density is proposed to monitor the particles' performance. When below a statistically controlled threshold value, our approach triggers smoothing for obtaining a better estimate of the initial state in the case of a poor prior. We find that combining a moving horizon smoother with SMC is very effective for recovering from a poor prior and develop an integrated practical approach that combines these two powerful tools.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=22732912

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4190–4196

Titre :	Novel flame - retardant and antidripping branched polyesters prepared via phosphorus - containing ionic monomer as end - capping agent
Type de document :	texte imprimé
Auteurs :	Jun-Sheng Wang, Auteur ; Hai-Bo Zhao, Auteur ; Xin-Guo Ge, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4190–4196
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Ionic Monomer
Résumé :	A series of novel branched polyester-based ionomers were synthesized with trihydroxy ethyl esters of trimethyl-1,3,5-benzentricarboxylate (as branching agent) and sodium salt of 2-hydroxyethyl 3-(phenylphosphinyl)propionate (SHPPP, as end-capping agent) by melt polycondensation. The chemical structures of the branched polyester-based ionomers were confirmed with 1H and 31P NMR spectra. The effects of branching and ionic end groups on the melt behavior and thermal properties were investigated by differential scanning calorimetry and thermogravimetric analysis. The flammability and fire behavior were characterized by limiting oxygen index (LOI) and cone calorimeter. The LOI values of branched poly(ethylene terephthalate)s (PETs) are higher than that of pure PET. The cone calorimeter parameters of the samples such as heat release rate, total heat release, and time to ignition indicate that the fire safety of branched polyester-based ionomers is improved by introducing SHPPP. The effects of SHPPP on accelerating char forming and antidripping could be observed clearly from the pictures of the samples after LOI test.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie100057n

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4181–4189

Titre :	Dynamic Water Transport in a Pigmented Porous Coating Medium : Novel Study of Droplet Absorption and Evaporation by Near-Infrared Spectroscopy
Type de document :	texte imprimé
Auteurs :	Carl-Mikael Tag, Auteur ; Mikko Juuti, Auteur ; Kimmo Koivunen, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4181–4189
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Dynamic Porous Coating
Résumé :	The dynamic wetting of, and absorption into, model porous coatings in the form of compressed particulate pigment tablets by monocomponent, dual-component, and multicomponent liquid droplets has been studied by observation of apparent contact angle and near-infrared spectroscopy to identify the liquid water/moisture content. The absorption of the liquids was studied in a corresponding vapor-saturated environment. Liquid evaporation was determined for the tablets at both equilibrium starting pore saturation and under limited volume-filling conditions as evaporation proceeds. The changes in water and moisture content within the coatings as a function of time were also determined gravimetrically to relate the water uptake and evaporation being observed to changes in the near-infrared spectral data. Model and commercial offset printing fountain solutions were compared with respect to both absorption and evaporation. For the solutions containing isopropyl alcohol in water, a nonlinear behavior in the water response in the near-infrared spectra during absorption is observed as a function of time, which can be related to the fast evaporation of the alcohol. The nonlinear region was followed by a decline in water and moisture content as the penetration/evaporation of the water phase proceeded. Comparing the near-infrared water volume dependency in the upper layers of the structure with weight loss during evaporation showed that the mechanism of liquid transport to the surface−air interface reflected the logarithmic volume distribution of pore sizes, as might be expected from capillarity considerations and pore condensation hysteresis.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie1000289

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4175–4180

Titre :	Synthesis of carbonaceous poly(furfuryl alcohol) membrane for water desalination
Type de document :	texte imprimé
Auteurs :	Li He, Auteur ; Li, Dan, Auteur ; Guangyou Zhang, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4175–4180
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Water Desalination
Résumé :	A novel carbonaceous poly(furfuryl alcohol) (CPFA) membrane was fabricated by partially carbonizing a poly(furfuryl alcohol) (PFA) layer supported on a commercial polysulfone substrate with high-concentration sulfuric acid at room temperature. Gas permeation experiments suggested that the PFA membrane became microporous after sulfuric acid treatment. ATR-IR spectra showed that the furan structure of PFA was degraded by the high-concentration sulfuric acid, forming CPFA. As compared with the PFA membrane, the CPFA membrane exhibited significantly enhanced chlorine resistance and water desalination properties. The CPFA membrane had a salt rejection of around 93.3% and a water permeability of 1.54 L·μm·m−2·h−1·bar−1. After the chlorine treatment, the CPFA membrane exhibited a salt rejection of 73.7% and a water permeability of 2.01 L·μm·m−2·h−1·bar−1, whereas the PFA membrane had a salt rejection of only 60.1% and a water permeability of 0.17 L·μm·m−2·h−1·bar−1.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901886c

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4169-4174

Titre :	Microwave - assisted preparation of Mo2C/CNTs nanocomposites as efficient electrocatalyst supports for oxygen reduction reaction
Type de document :	texte imprimé
Auteurs :	Min Pang, Auteur ; Chuang Li, Auteur ; Ling Ding, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4169-4174
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Nanocomposite Preparation Microwave
Résumé :	Nanostructured Mo2C/CNTs composites have been synthesized by using a novel methodology of microwave-assisted thermolytic molecular precursor with Mo(CO)6 as single source precursor. Pt electroeatalysts supported on the Mo2C/CNTs composites were prepared by using the modified ethylene glycol method. The resulting Mo2C/CNTs and Pt―Mo2C/CNTs were characterized by inductively coupled plasma-optical emission spectroscopy, thermogravimetric analysis, X-ray diffraction, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The rotating disk electrode experiments were used to measure electrocatalytic activity for oxygen reduction reaction. The results showed highly dispersed sphere-like Mo2C and Pt particles with 3—6 nm can be prepared upon CNTs by the above-mentioned methods. The formation process of Mo2C includes the following steps: decomposition of Mo(CO)6 precursor to the metallic Mo and CO, CO dismutation reaction, formation of the MoOxCy by the metallic Mo and CO, the MoOxCy carburization to Mo2C, and further carburization of Mo2C to Mo3C2. The Pt―Mo2C/CNTs sample gave higher electrochemical surface area and activity for oxygen reduction reaction with a more positive onset potential in acid solution than those of Pt/CNTs under the same condition, which was attributed to the synergistic effect among Pt, Mo2C, and CNTs. The findings indicate that Mo2C is an inexpensive and promising alternative to precious metal and worthy of further exploring for other applications in catalysis.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=22732908

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4162–4168

Titre :	Preparation of monodispersed uniform silica spheres with large pore size for fast adsorption of proteins
Type de document :	texte imprimé
Auteurs :	Zheng Zhai, Auteur ; Yujun Wang, Auteur ; Yangcheng Lu, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4162–4168
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Adsorption Pore size Preparation
Résumé :	In this paper, a “temperature-induced gelation” method, combined with microfluidic flows, has been developed to synthesize the uniform silica spheres with large pore structures for the fast adsorption of bovine serum albumin (BSA). The reversible-thermosentive property of methylcellulose (MC) and auxiliary function of poly(ethylene glycol) (PEG) were introduced to realize a fast gelation in a coaxial microfludic device. The effects of temperature and MC concentration on the gelation process were investigated by monitoring the change of viscosity of sol system over time. The silica spheres with different morphologies of internal structure were synthesized by adjusting the concentration of MC. The prepared silica spheres had large pore volumes (>2.0 mL/g) and an average mesopore diameter of >12 nm. Meanwhile, a large amount of macropores existed in the silica spheres. The bimodal mesopore-marcopore structure resulted in a high protein adsorption capacity (590 mg/g) and a fast adsorption rate (reaching equilibrium within 9 h).
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=22732907

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4156–4161

Titre :	Microfluidic fabrication of monodispersed pharmaceutical colloidal spheres of atorvastatin calcium with tunable sizes
Type de document :	texte imprimé
Auteurs :	Hai-Xia Zhang, Auteur ; Jie - Xin Wang, Auteur ; Lei Shao, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4156–4161
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Microfluidic
Résumé :	In this work, monodispersed pharmaceutical colloidal spheres of atorvastatin calcium (AC) with tunable sizes have been synthesized in a microfluidic system at continuous flow conditions. The influences of the key parameters, including the concentration of the AC methanol solution, the overall flow rate, the flow rate of isopropanol, and the flow rate of the AC methanol solution on particle size and size distribution were discussed. The results indicated that the drug concentration and the flow rate could efficiently control the particle size and improve the polydispersity of the resulting particles. The particle size decreased from 760 to 300 nm with an increase in the AC concentration from 30 to 60 mg/mL and significantly increased from 430 to 2500 nm with an increase in the flow rate of the AC methanol solution from 2.7 to 16 mL/min. However, with the increase of the overall flow rate at a fixed flow ratio of 10, the particle size slightly decreased from 240 (10/1 mL/min) to 210 nm (30/3 mL/min) and then dramatically increased to 680 nm (80/8 mL/min). Also, the particle size first decreased and then increased with an increase in the flow rate of isopropanol. The prepared AC colloidal spheres were amorphous and displayed enhanced dissolution rate compared with the commercial AC. This work shows that the continuous synthesis in a microfluidic reactor is a simple and economic way to prepare monodispersed pharmaceutical colloidal particles or nanoparticles with tunable sizes.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901365w

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4149–4155

Titre :	Kinetic study of H2 oxidation in the preferential oxidation of CO on a nanosized Au / CeO2 catalyst
Type de document :	texte imprimé
Auteurs :	Jing Xu, Auteur ; Ping Li, Auteur ; Xingfu Song, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4149–4155
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Kinetic Oxidation Catalyst
Résumé :	Kinetic study of H2 oxidation in the preferential oxidation (PROX) of CO was implemented over a nanosize Au/CeO2 catalyst in a temperature range 313−353 K. The Langmuir−Hinshelwood mechanism was proposed to be mainly responsible for H2 oxidation, and CO oxidation can be accelerated by coadsorbed H at low temperatures. On the other hand, the water in the system has proved to suppress both CO and H2 oxidation by increasing the energy bars. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) of CO adsorption on the Au surface indicates that linear CO−Au bond can be weakened in the presence of H2; meanwhile, water can be a poison taking effects via the bonding of water and the lattice oxygen at the interface of Au/CeO2. The irreversible loss of activity during reaction may be caused by the reconstruction of Au particles, at least in part.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie100325y

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4140–4148

Titre :	Cobalt fischer − tropsch catalysts using nickel promoter as a rhenium substitute to suppress deactivation
Type de document :	texte imprimé
Auteurs :	Erling Rytter, Auteur ; Torild H. Skagseth, Auteur ; Sigrid Eri, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4140–4148
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Catalysts
Résumé :	Catalysts with cobalt as the Fischer−Tropsch (FT) metal and nickel and/or rhenium as promoters on alumina of different pore sizes, a stabilized alumina, silica, or titania as supports were investigated for activity, selectivity, and deactivation up to 800 h of operation in a fixed-bed reactor. From the observed selectivities, there is no indication that nickel as a promoter with a loading up to 5 wt % influences the selectivities to higher hydrocarbons for low-temperature (<250 °C) cobalt FT synthesis. Nickel is found to have a profound impact on the catalytic activity, and the start of run activity, steady-state level, and deactivation rate are influenced. The freshly reduced catalyst is nearly inactive, but the activity increases rapidly to a stable level which is significantly higher than for catalysts without nickel. It appears that nickel can substitute rhenium as a reduction and activity promoter. The steady-state activity is maintained constant for a prolonged time, but expected deactivation commences after ca. 150 h time on stream.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie100308f

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4132–4139

Titre :	Synthesis and kinetics of highly energetic intermediates by micromixers : direct multistep synthesis of sodium nitrotetrazolate
Type de document :	texte imprimé
Auteurs :	Nikolay Zaborenko, Auteur ; Edward R. Murphy, Auteur ; Jason G. Kralj, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4132–4139
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Kinetics Micromixers
Résumé :	A modular silicon micromixer is designed and fabricated for high-flow rapid mixing at a wide range of reaction conditions. The mixer operates by splitting two inlet flows into a large number of channels, interdigitating them, and constricting the laminated flow to create submicrometer diffusion lengths. Mixing is quantified using the Villermaux−Dushman method, with UV−vis detection of the photoactive species, and compared against a commercial micromixer. Micromixers and tubing are then used to perform a quantitative kinetic study of the direct two-step synthesis of sodium nitrotetrazolate (NaNT) by a Sandmeyer type reaction via a reactive diazonium intermediate. Orders of reactions and temperature dependence of both steps, as well as pH and ionic strength dependence of the second step, are evaluated. Successful production of 4.4 g/h of NaNT in solution is ultimately achieved in a compact footprint using the kinetic data, verifying the potential for scaling to typical production amounts.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie100263p

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4123-4131

Titre :	Electrochemical Degradation of Perchloroethylene in Aqueous Media : Influence of the Electrochemical Operational Variables in the Viability of the Process
Type de document :	texte imprimé
Auteurs :	Veronica Saez, Auteur ; Maria Deseada Esclapez, Auteur ; Ignacio Tudela, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4123-4131
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Electrochemical Aqueous Media
Résumé :	An extensive study of the influence of the operational variables in the electrochemical degradation of perchloroethylene in water has been carried out using an electrochemical filter-press reactor. The influences of the initial concentration, volumetric flow, and electrode geometry and nature on the kinetics, degradation efficiency, and mechanism have been analyzed by determining the values of process performance parameters such as fractional conversion, degradation efficiency, mass balance error, and selectivity. The best results obtained were a fractional conversion higher than 85%, degradation efficiencies of 65%, selectivities close to 0.8, and energetic consumption around 3 kWh m−3 obtained with two-dimensional electrodes. Three-dimensional carbon electrodes did not provide a more competitive option.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=22732902

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4117–4122

Titre :	Continuous - flow esterification of free fatty acids in a rotating packed bed
Type de document :	texte imprimé
Auteurs :	Yi-Hung Chen, Auteur ; Wang-Chi Lin, Auteur ; Cheng-Hsien Tsai, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4117–4122
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Esterification Fatty Acid
Résumé :	The continuous-flow esterification of free fatty acids (FFAs) with methanol for the production of fatty acid methyl esters (FAMEs) using a rotating packed bed (RPB) is presented herein. The RPB, which provides a high centrifugal force and has an adjustable rotational speed, was employed as a novel esterification reactor. The following variables were investigated for their effects on the esterification efficiency: the methanol-FFA molar ratio, the estimated hydraulic retention time, the rotational speed of the packed bed, the reaction temperature, and the catalyst dosage. The conversion of the FFAs in the RPB system significantly depended on the experimental conditions, which influenced the residence time distribution, the esterification reaction rate, and the micromixing intensity. Due to its excellent micromixing characteristics, the RPB system exhibited good efficiency for the esterification reaction in continuous-flow operation. The RPB system achieved the conversion of the FFAs of 10.0−96.6% and the productivity of FAMEs of 0.042−1.20 mol/min.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie100112s

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4107–4116

Titre :	Tuning of the activity and induction period of the polymerization of propylene oxide catalyzed by double metal cyanide complexes Bearing B - Alkoxy alcohols as complexing agents
Type de document :	texte imprimé
Auteurs :	Sang Hyun Lee, Auteur ; In Kyu Lee, Auteur ; Ju Young Ha, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4107–4116
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Oxide Metal
Résumé :	For the development of commercially viable catalyst systems for the polymerization of propylene oxide (PO), a series of double metal cyanide (DMC) complexes have been developed by reacting aqueous zinc(II) chloride with aqueous potassium hexacyanocobaltate(III) in the presence of various complexing agents (CAs) such as 2-methoxyethanol, 2-ethoxyethanol, 2-propoxyethanol, 2-butoxyethanol (BE), 1-methoxypropan-2-ol, 1-ethoxypropan-2-ol, 1-propoxypropan-2-ol, and 1-butoxypropan-2-ol (BP) with different polarities and tert-butyl alcohol (tBuOH). The catalyst composition was estimated by combining elemental analysis with thermogravimertic analysis. The coordination of the CA can be identified by employing X-ray photoelectron spectroscopy, X-ray diffraction patterns, and infrared spectroscopy of the catalysts. Pursuing a catalyst system showing favorable polymerization behavior for commercial aspects of both catalytic activity and reaction control, the kinetics of PO polymerizations were investigated by using 4 and 8 L reactors equipped with pilot programmable logic controller systems. While a DMC catalyst bearing tBuOH as a CA showed a long induction period, it gave a very high overall rate of polymerization once activated, resulting in severe exothermic reactions that are hard to control. This problem could be successfully overcome by using the DMC catalysts bearing BE or BP as a CA. All polyether polyols were analyzed by measuring their unsaturation level, molecular weight, and distribution. All of the polyols produced featured a low level of unsaturation (0.014−0.024 mequiv g−1), moderate number-average molecular weights (900−3400), and very narrow polydispersities (1.04−1.19).
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie1000967

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4099–4106

Titre :	Reversible autocatalytic hydrolysis of alkyl formate : kinetic and reactor modeling
Type de document :	texte imprimé
Auteurs :	Olatunde Jogunola, Auteur ; Tapio Salmi, Auteur ; Kari Eranen, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4099–4106
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Hydrolysis Kinetic
Résumé :	The kinetics and thermodynamics of alkyl formate hydrolysis in liquid phase were studied in a laboratory-scale autoclave at temperatures between 333 and 383 K using different molar ratios of the reactants. The process was found to exhibit an autocatalytic effect due to the acid formed. More so, the rate of neutral hydrolysis of ethyl formate is faster compared to methyl formate in the uncatalyzed reaction. However, the autocatalytic effect is more pronounced in methyl formate hydrolysis. In addition, the effect of adding a small amount of formic acid as an initial charge upon the equilibrium conversion and kinetics was investigated, and it was found that the addition improved the reaction rate by reducing the induction period but it suppressed slightly the equilibrium conversion. A kinetic model was proposed to explain these experimental trends, and the model agreed well with the experimental results.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie902031d

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4091–4098

Titre :	Application of a combined catalyst and sorbent for steam reforming of methane
Type de document :	texte imprimé
Auteurs :	Karl O. Albrecht, Auteur ; Justinus A. Satrio, Auteur ; Brent H. Shanks, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4091–4098
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Catalyst Methane
Résumé :	The performance of a combined catalyst and sorbent material designed for reforming hydrocarbons was evaluated by reacting methane with steam at different temperatures and pressures in a reactor packed with the material. The combined material was in the form of small spherical pellets comprised of a sorbent core of lime encased in a porous shell made largely of sintered alumina that supported a nickel catalyst. On the basis of previous research, two shell formulations were included in the study. One shell formulation contained a small quantity of CaO for strengthening of the shells, whereas the other contained a similar quantity of La2O3. Reaction testing of the combined catalyst and sorbent over a temperature range of 550−650 °C and a pressure range of 1.0−10.0 atm showed that pellets with either shell formulation were capable of producing H2 at or near thermodynamic equilibrium levels during a period when CO2 was being rapidly absorbed by the core material. Limited lifecycle testing of the combined catalyst and sorbent was also conducted at 650 °C and 1.0 atm over 10 cycles of H2 production and sorbent regeneration. A product stream with 98 mol % H2 (dry basis) was produced during the rapid CO2 absorption period of each cycle. However, the length of this period declined with each cycle.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901914c

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4080-4090

Titre :	Synthesis, characterization, and catalytic activity of phosphorus modified H - ZSM - 5 catalysts in selective ethanol dehydration
Type de document :	texte imprimé
Auteurs :	Kanaparthi Ramesh, Auteur ; Jie Chang, Auteur ; Yi-Fan Han, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4080-4090
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Dehydration Catalyst Catalyst activity
Résumé :	Phosphorus (P) modified H-ZSM-5 catalysts were prepared by wet impregnation method by varying P loadings from 0 to 7.43 wt % using phosphoric acid (H3PO4) as the P source. The catalysts were tested for ethanol dehydration in the temperature range of 523—723 K. The P-modified catalysts were found to be highly active and selective toward ethylene at 673 K and atmospheric pressure. In addition, the P-modified catalysts were found to be extremely stable more than 200 h without any sign of deactivation. However, the selectivity was found to be strongly dependent on several factors such as P content, reaction temperature, and space velocity (WHSV). The P-modified ZSM-5 catalysts were also found to be highly active for the dehydration of aqueous ethanol solutions (10 wt %) showing very high ethylene selectivity (above 98%) at significantly lower temperature 623 K. The catalysts were thoroughly characterized using various methods, including N2 physisorption, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric differential thermal analysis (TG-DTA), 1H, 27Al, and 31P magic angle spinning nuclear magnetic resonance (MAS NMR), and amonia temperature programmed desorption (NH3-TPD). 27Al MAS NMR spectra suggest that P addition facilitate the breaking of Si―O―Al bond that lead to a partial dealumination. NH3-TPD results indicate that total acidity as well as density of high strength acid sites were decreased with P loading.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=22732897

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4070–4079

Titre :	Numerical simulation of the gas − solid flow in fluidized - bed polymerization reactors
Type de document :	texte imprimé
Auteurs :	De-Pan Shi, Auteur ; Zheng-Hong Luo, Auteur ; An-Yi Guo, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4070–4079
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Gas Solid
Résumé :	A three-dimensional computational fluid dynamics (CFD) model, using an Eulerian−Eulerian two-fluid model which incorporates the kinetic theory of granular flow, was developed to describe the gas−solid two-phase flow in fluidized-bed polymerization reactors. Corresponding simulations were carried out in a commercial CFD code Fluent. The entire flow field in the reactors was calculated by the model. The predicted pressure drop data were in agreement with the classical calculated data. In addition, the model was used to describe the solid holdup distributions, the bubble behaviors, and the solid velocity vectors in the free and agitated fluidized-bed polymerization reactors, respectively. The effects of the addition of an agitator on the gas−solid flow behaviors were preliminarily investigated via the model. The simulation results showed that the addition of an agitator can strengthen the fluidization efficiency and reduce the operation stability of the bed. However, the simulation results also showed that the total fluidization quality of the free fluidized bed was higher than that of the agitated fluidized bed at a superficial gas velocity of 0.5 m·s−1.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901424g

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4063-4069

Titre :	Preparation, characterization, and activity evaluation of H - ZSM - 5 catalysts in vapor - phase methanol dehydration to dimethyl ether
Type de document :	texte imprimé
Auteurs :	Samaneh Hassanpour, Auteur ; Majid Taghizadeh, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4063-4069
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Dehydration Catalyst Preparation
Résumé :	Using the hydrothermal crystallization method, a highly crystalline series of H-ZSM-5 zeolites were prepared in different Si/Al molar ratios (ranging from 25 up to 250). The performance of prepared catalysts was a subject of assessment in the process of methanol dehydration to dimethyl ether (DME), where a stainless steel fixed-bed flow reactor at 573 K and 16 barg with WHSV of 26.5 h 1 was used. The catalysts were characterized by BET, XRD, NH3-TPD, ICP, TGA/DTA, TPH, and SEM techniques. According to the experimental results, the catalytic activity and surface acidity were increased with an increase in the Si/Al molar ratio up to 125 and then decreased. The sample with a Si/Al molar ratio of 125 [H-ZSM-5(125)] exhibited the best conversion and highest activity in methanol dehydration to DME. Before a comprehensive study was made on the synthesized zeolite catalysts, the dehydration reaction with crude methanol was studied over a commercial H-ZSM-5 catalyst under identical conditions. Results show that prepared catalysts have a better performance than commercial ones.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=22732895

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4055-4062

Titre :	Char formation mechanism in supercritical water gasification process : a study of model compounds
Type de document :	texte imprimé
Auteurs :	Athika Chuntanapum, Auteur ; Yukihiko Matsumura, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4055-4062
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Modeling Gasification Supercritical state Formation mechanism
Résumé :	Char is one of the undesirable products in the supercritical water gasification of biomass, causing a reduction in carbon gasification efficiency. 5-HMF (5-hydroxymethylfurfural) is believed to be an intermediate in the char formation pathway. In this Article, the rate of formation of char particles obtained from experiments using glucose (a biomass model compound) was compared to that from experiments using 5-HMF (Chuntanapum and Matsumura, 2009). The glucose experiments were conducted in a temperature range of 300—400 °C, at 25 MPa, and for a residence time up to 70 s. The initial concentration of glucose was varied from 1.5 to 3 wt % (i.e., 0.083 to 0.167 M). Glucose was found to produce char particles 2 orders of magnitude faster than 5-HMF feedstock. The copresence of the other glucose decomposition products is thought to cause the difference in the char formation mechanism (i.e., the side reaction between 5-HMF and the other decomposition products) from that of 5-HMF alone. FT-IR and Raman spectroscopy of the solid products was carried out.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=22732894

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4044-4054

Titre :	Effect of the synthesis method of MgAl2O4 and of Sn and Pb addition to platinum catalysts on the behavior in n - butane dehydrogenation
Type de document :	texte imprimé
Auteurs :	Sonia Bocanegra, Auteur ; Maria Julia Yanez, Auteur ; Osvaldo Scelza, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4044-4054
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Dehydrogenation Catalyst
Résumé :	The MgAl2O4 spinels, synthesized by using two different methods (ceramic and coprecipitation), show very low acidity and good dispersion capacity of the metallic phase, these properties being suitable for the use of these materials as supports. However, MgAl2O4ccr displays higher strong acidity than MgAl2O4cop which seems to influence the metal—support interaction, since Pt/MgAl2O4cer catalyst shows higher metallic dispersion, lower metal particle sizes, and better catalytic behavior than the Pt/MgAl2O4cop one. The Sn addition to Pt/ MgAl2O4 improves the performance in the n-butane dehydrogenation process, increasing the activity, stability, and selectivity to butenes. This behavior is due to the presence of important Pt—Sn interactions, mainly in bimetallic catalysts supported on MgAl2O4cer. On the other hand, the Pb addition to monometallic catalysts does not enhance the catalytic performance in dehydrogenation. This behavior is in agreement with the characterization results of metallic phase that indicate important blocking effects in PtPb/MgAl2O4cer catalysts, and segregation effects in PtPb/MgAl2O4cop. In conclusion, the ceramic method of MgAl2O4 preparation provides the best support for PtSn catalysts in n-butane dehydrogenation reaction.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=22732893

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4036–4043

Titre :	Temperature zonal combustion reactor for the 15 - nitrogen and 13 - carbon isotopic determination of enriched biosynthetic materials
Type de document :	texte imprimé
Auteurs :	Michael May, Auteur ; John Kuo, Auteur ; Michael Gray, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4036–4043
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Carbon Isotopic
Résumé :	A temperature distribution was imposed on a solid−gas reactor to help accomplish the 15-nitrogen or 13-carbon isotopic determination of biosynthetic materials such as algal protein-15N. The temperature zonal combustion reactor (TZCR) can operate offline from its mass spectrometer, and this reactor facilitates the stable isotopic determination of highly enriched biomaterials (>95 atom % isotope). The reactor structure is a glass pipe comprising a quartz segment, transition segments, and threaded sockets. Precise positioning of the reactor within a tubular furnace establishes a longitudinal temperature distribution that is used to drive solid−gas chemistry in distinct zones: sample, catalyst, and sorbent. The TZCR module typically includes a reactor pipe, gastight valve, sample, reactants, reactant containers, and furnace. An important advantage of TZCR-mass spectrometer is preliminary vacuum heat treatment of the crude sample to remove volatile impurities before sample combustion (enabling isotopic enrichment determination of the analyte). For the determination of 15N enrichment, sample combustion at 650 °C in oxygen was supplemented by Fe3O4 catalyst near 500 °C and Li2O at 25 °C that concertedly promoted the intrareactor depletion of CO, CO2, and H2O. As a result, the primary gaseous product was dinitrogen. After 15N sample conversion, the reactor was coupled to a quadrupole MS for product analysis (N2+ ions for 15N determination). Accordingly, uniformly enriched biomaterials were analyzed such as algal protein-15N that measured 99.0 ± 0.12 atom % 15N. By adapting the methodology for 13C determination, lyophilized algal cells-13C were determined to be 99.1 ± 0.06 atom % 13C. Stable isotope enrichments were computed by minimizing the numeric differences between theoretical and actual MS signals.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie100072z

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4031–4035

Titre :	Large-Scale Synthesis of Double-Walled Carbon Nanotubes in Fluidized Beds
Type de document :	texte imprimé
Auteurs :	Oscar M. Dunens, Auteur ; Kieran J. MacKenzie, Auteur ; Andrew T. Harris, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4031–4035
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Carbon Nanotubes
Résumé :	Double-walled carbon nanotubes (DWCNTs) are a unique allotrope of carbon with numerous potential applications including use in electronic and nanomechanical devices. However, existing methods and reaction conditions for DWCNT synthesis are inherently unscaleable, and production is limited to gram per hour quantities. Here, we report the synthesis of well-graphitized DWCNTs using fluidized bed chemical vapor deposition on an alumina-supported iron−molybdenum catalyst. Reaction products were analyzed using thermogravimetric analysis, Raman spectroscopy, and scanning and transmission electron microscopies. At a synthesis temperature of 850 °C and with use of methane as the carbon source, a 278% carbon yield relative to the weight of the metal catalyst was obtained. Carbon products consisted of approximately 75% DWCNTs with a good degree of wall graphitization (IG/ID = 4.85). The production technique and reaction conditions described here are capable of being applied at industrial scale.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie100059q

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4026-4030

Titre :	Alternative method with amperometric detection for ranitidine determination
Type de document :	texte imprimé
Auteurs :	Valeria Pfaffen, Auteur ; Patricia Inés Ortiz, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4026-4030
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Amperometric Detection Ranitidine
Résumé :	An alternative, simple, and reliable FIA amperometric method for ranitidine quantification was developed. A working glassy carbon electrode and a Ag\|AgCl\|NaCl (3 M) reference electrode were used. The determination is based on the electrochemical oxidation of ranitidine at 1.2 V in phosphate buffer solution (pH 7.2). The determination of ranitidine in the range of 1 × 10−6 to 2 × 10−5 M was possible with a sampling frequency of 120 h−1. The method was validated and satisfactorily applied to the determination of ranitidine in pharmaceutical formulations with a low limit of detection (6 × 10−7 M) and a quantitative recovery with no interferences from excipients. The results compare favorably with those obtained by the liquid chromatographic method of the U.S. Pharmacopoeia.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901895a

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4018–4025

Titre :	Catalytic studies toward synthesis of 2,6 - dimethylnaphthalene from 1 - (p - Tolyl) - 2 - methylbutane
Type de document :	texte imprimé
Auteurs :	Kari Vahteristo, Auteur ; Kari-Matti Sahala, Auteur ; Salme Koskimies, Auteur
Année de publication :	2010
Article en page(s) :	pp. 4018–4025
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Catalysts
Résumé :	In this work experiments have been performed in order to study the synthesis of 2,6-dimethylnaphthalene (DMN) via dehydrocyclizing 1-(p-tolyl)-2-methylbutane over Pt/SiO2, V/Ca/Al2O3, and unimpregnated or potassium-impregnated Cr2O3/Al2O3 catalysts. The obtained liquid product mixture consisted of 1,6-cyclization products (dimethylnaphthalenes) and dealkylated 1,6-cyclization products (2-methylnaphthalene and naphthalene), 1,5-cyclization products (trimethylindanes and -indenes), and fragmentation products (mainly p-xylene and 3-(p-tolyl)-propylenes) and 1-(p-tolyl)-2-methylbutenes. Among 10 possible DMN isomers 1,5-, 1,6-, 2,6-, and 2,7-DMN were identified. Metal catalysts V/Ca/Al2O3 (5 wt % vanadium) and Pt/SiO2 (1 wt % platinum) were slightly more active than unimpregnated commercial Cr2O3/Al2O3. After 1 h on-stream time the conversion of 1-(p-tolyl)-2-methylbutane was 96 mol % when the artificial contact time (1/weight-hourly space velocity (WHSV)) was 5.7 h at 783 K over unimpregnated Cr2O3/Al2O3. Potassium impregnation decreased the conversion into 84 mol % because of the decreased Brunauer−Emmett−Teller surface area (from 97 m2/g unimpregnated to 70 m2/g potassium-impregnated catalyst).
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9008887

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 3993–4017

Titre :	Planning and scheduling under uncertainty : A review across multiple sectors
Type de document :	texte imprimé
Auteurs :	Peter M. Verderame, Auteur ; Josephine A. Elia, Auteur ; Jie Li, Auteur
Année de publication :	2010
Article en page(s) :	pp. 3993–4017
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Uncertainty analysis
Résumé :	This paper provides an overview of the key contributions within the planning and scheduling communities with specific emphasis on uncertainty analysis. As opposed to focusing in one particular industry, several independent sectors have been reviewed in order to find commonalities and potential avenues for future interdisciplinary collaborations. The objectives and physical constraints present within the planning and scheduling problems may vary greatly from one sector to another; however, all problems share the common attribute of needing to model parameter uncertainty in an explicit manner. It will be demonstrated through the literature review that two-stage stochastic programming, parametric programming, fuzzy programming, chance constraint programming, robust optimization techniques, conditional value-at-risk, and other risk mitigation procedures have found widespread application within all of the analyzed sectors. This review is the first work which attempts to provide a comprehensive description of the advances and future directions for planning and scheduling under uncertainty within a variety of sectors.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie902009k

Industrial & engineering chemistry research / Paul, Donald R. . Vol. 49 N° 9

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