Catalogue en ligne Bibliothèque Ecole Nationale Polytechnique d'Alger

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 11112-11118

Titre :	Preparation of a catalyst for selective hydrogenation of pyrolysis gasoline
Type de document :	texte imprimé
Auteurs :	Zhiming Zhou, Auteur ; Tianying Zeng, Auteur ; Zhenmin Cheng, Auteur
Année de publication :	2011
Article en page(s) :	pp. 11112-11118
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Pyrolysis Hydrogenation Catalyst Preparation
Résumé :	Novel palladium catalysts supported on alumina supports with the hierarchically macro-/mesoporous structure were prepared and applied to selective hydrogenation of pyrolysis gasoline. The textural, structural, and morphological properties of the catalyst supports were studied by SEM, XRD, and N2 adsorption-desorption techniques. The results showed that the hierarchically macro-/mesoporous structures of these materials were formed by a spontaneous self-assembly mechanism, and the presence of surfactant molecules, which influenced the mesopore size distribution, had almost no effects on the macroporous channels. Calcination treatments of the prepared materials revealed their high thermal stability. By comparison with a commercial catalyst without the hierarchically porous structure, these novel catalysts exhibited much better catalytic performance, that is, higher activity and selectivity, which was ascribed mainly to their unique structures of hierarchical mesopores and macropores. Finally, the stability of the novel catalysts was tested. Both experimental observations and TGA analysis of the used catalysts indicated good stability of these catalysts.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23448009

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 11101-11111

Titre :	Kinetic studies on Pd / CexZr1 − xO2 catalyst for methane combustion
Type de document :	texte imprimé
Auteurs :	Stefania Specchia, Auteur ; Fabio Conti, Auteur ; Vito Specchia, Auteur
Année de publication :	2011
Article en page(s) :	pp. 11101-11111
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Combustion Catalyst Kinetics
Résumé :	In recent years, catalytic combustion of CH4 has been extensively studied as an alternative option to conventional thermal combustion for the production of heat and energy in view of its capability to achieve effective combustion at much lower temperatures than in conventional oxidation processes, with high efficiency and reduced pollutants such as CO and NOx. In this paper a kinetic study on 2% Pd over CexZr1-xO2 catalyst is presented. The catalyst was prepared by solution combustion synthesis, fully characterized and tested for CH4 catalytic combustion. A kinetic study was carried out in a continuous recycle reactor, operated in differential conditions. Twelve different possible rate equations belonging to Eley-Rideal, Langmuir-Hinshelwood, and Mars van Krevelen models were fitted to the experimental data. The best fitting belonged to a Mars van Krevelen mechanism, considering the concentration of the molecular O2 adsorbed on a single active site, which successively dissociated creating an active site with atomic O2. The obtained kinetic parameters were inside the range reported in literature for similar catalysts (Eact,1 = 23.8 kJ mol―1; Eact,2 = 31.9 kJ mol 1; E*act,1 = 5.4 kJ mol―1). For comparison, to better assess the catalytic role of Pd in the CH4 combustion, also the kinetic parameters of the sole carrier, CexZr1-xO2, were calculated. The best rate equation for the carrier was based on a different Mars van Krevelen mechanism, a simpler one, involving the surface reaction between adsorbed molecular oxygen and methane from the gas phase (Eact,1 = 79.6 kJ mol―1, Eact,2 = 1 14.6 kJ mol―1).
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23448008

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 11098-11100

Titre :	Improving the stability of cobalt fischer − tropsch catalysts by boron promotion
Type de document :	texte imprimé
Auteurs :	Mark Saeys, Auteur ; Kong Fei Tan, Auteur ; Jie Chang, Auteur
Année de publication :	2011
Article en page(s) :	pp. 11098-11100
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Fischer Tropsch catalyst Stability
Résumé :	Supported Co catalysts exhibit favorable activity and selectivity for Fischer―Tropsch synthesis (FTS) but deactivate slowly. To explore deactivation by carbon deposition, the stability of various forms of deposited carbon was evaluated using density functional theory (DFT). A surface carbide and graphene islands were calculated to be thermodynamically stable. Two forms of deposited carbon are also distinguished experimentally after 200 h of FTS. On the basis of this mechanistic insight, boron was proposed as a promoter to enhance the stability of Co catalysts. DFT calculations indicate that boron and carbon display similar binding preferences, and boron could selectively block the deposition of resilient carbon deposits. To evaluate the theoretical predictions, supported 20 wt % Co catalysts were promoted with 0.5 wt % boron and tested under realistic FTS conditions. Boron promotion was found to reduce the deactivation rate 6-fold, without affecting selectivity and activity.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23448007

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 11087-11097

Titre :	Mitigating deactivation effects through rational design of hierarchically structured catalysts : Application to hydrodemetalation
Type de document :	texte imprimé
Auteurs :	Sanjeev M. Rao, Auteur ; Marc-Olivier Coppens, Auteur
Année de publication :	2011
Article en page(s) :	pp. 11087-11097
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Catalyst Design Deactivation
Résumé :	The broad pore network of a hierarchically structured hydrodemetalation catalyst, containing both nano- and macropores, is mathematically optimized to maximize the conversion of nickel metalloporphyrins in crude oil residue. A random spheres model (RSM) describing the nanoporous catalyst at the mesoscale is combined with a two-dimensional continuum approach to model the entire catalyst at the macroscale. Catalysts with a spatially uniform as well as a nonuniform macroporosity distribution are optimized. The macroporosity profiles of the optimal nonuniform catalysts fluctuate about the optimal uniform value, while the spatially and temporally integrated reaction rates from both types of optimized catalysts are almost the same. Moreover, the integrated reaction rate of the optimal hierarchically structured catalysts are almost 8 times higher than the yield obtained from a purely nanoporous catalyst. For a time on stream of 1 year, approximately 21% less catalytic material is required in the optimal hierarchically structured catalyst, compared to the purely nanoporous one. The mathematical optimization tools employed here can be extended to other industrially important reactions affected by deactivation.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23448006

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 11079–11086

Titre :	Computational fluid dynamics - based multiobjective optimization for catalyst design
Type de document :	texte imprimé
Auteurs :	Shueh-Hen Cheng, Auteur ; Hsuan Chang, Auteur ; Yih-Hang Chen, Auteur
Année de publication :	2011
Article en page(s) :	pp. 11079–11086
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Design Catalyst Optimization Computational fluid dynamics
Résumé :	For an industrial secondary methane steam reformer with regular packing, catalyst design is accomplished by an integrated optimization approach, which includes the design of experiment, computational fluid dynamics (CFD) simulation, a response surface method, and a genetic algorithm, for multiobjective optimization. Both spherical and cylindrical catalysts are studied. The reactor performance considered for the catalyst design includes the pressure drop and hydrogen production, which constitute the binary objective functions for optimization. The optimal solutions reveal that a large pore diameter, near 1 μm, should be adopted for spherical catalysts. For cylindrical catalysts, the optimal design suggests the use of a 1-big-hole shape with a larger particle and pore size, 10-13 mm and near 1 μm, or a 4-hole shape with a smaller particle size of 6-8 mm.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23448005

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 11073–11078

Titre :	Assessment of methanol synthesis utilizing exhaust CO2 for chemical storage of electrical energy
Type de document :	texte imprimé
Auteurs :	Liisa K. Rihko-Struckmann, Auteur ; Andreas Peschel, Auteur ; Richard Hanke-Rauschenbach, Auteur
Année de publication :	2011
Article en page(s) :	pp. 11073–11078
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Methanol Electrical energy
Résumé :	The thermodynamic and operational boundaries to store electrical energy chemically are evaluated in this contribution. Methanol is considered as a candidate for chemical energy storage. The production of methanol from exhaust CO2 could be one way to recyle CO2 and lower the global CO2 emissions. Energetic analysis reveals that exergy losses are most severe in the parts of the system when electrical energy is converted to chemical (electrolysis) and when chemical energy is converted to electrical (power generation). In methanol production, the exergetic efficiency is 83.1%, when the chemical exergy of hydrogen and methanol, the exergy of the power input and the released heat are taken into consideration. The exergetic efficiency of the overall energy conversion-storage system including methanol as storage medium was evaluated to be between 16.2 and 20.0% depending on the applied conversion technology. Methanol is suitable not only as stationary energy storage, but it could also be used as fuel for transportation. The energy storage system with hydrogen as storage medium shows higher exergetic efficiency than the methanol route. However, the storage of hydrogen is clearly more complex and cost-intensive.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie100508w

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 11067–11072

Titre :	Kinetics of carbon dioxide removal by aqueous alkaline amino acid salts
Type de document :	texte imprimé
Auteurs :	Prakash D. Vaidya, Auteur ; Prashanti Konduru, Auteur ; Mukanth Vaidyanathan, Auteur
Année de publication :	2011
Article en page(s) :	pp. 11067–11072
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Kinetics Aqueous alkaline
Résumé :	Aqueous solutions containing alkaline salts of carboxylic or sulfonic amino acids represent candidate solvents with good potential for carbon dioxide (CO2) capture. In the present work, the CO2 reactions with potassium salts of glycine (aminoacetic acid) and taurine (2-aminoethanesulfonic acid) in aqueous solutions are investigated using a stirred-cell reactor. The reaction pathways are comprehensively described using the zwitterion and the termolecular mechanism. The investigated reactions belong to the fast pseudo-first-order reaction regime systems. The second-order rate constant for the CO2 reaction with potassium glycinate is determined, and its value at 303 K is evaluated to be 6.29 m3/(mol s). The liquid-side mass-transfer coefficient is estimated, and its value (0.006 cm/s) is consistent with those typical for stirred-cell reactors. Finally, it is determined that potassium glycinate promotes the activity of tertiary amines (e.g., N,N-diethylethanolamine).
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie100224f

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 11061-11066

Titre :	Fischer − tropsch synthesis using H2 / CO / CO2 syngas mixtures over a cobalt catalyst
Type de document :	texte imprimé
Auteurs :	Yali Yao, Auteur ; Diane Hildebrandt, Auteur ; David Glasser, Auteur
Année de publication :	2011
Article en page(s) :	pp. 11061-11066
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Catalyst Synthesis gas Carbon dioxide Fischer Tropsch synthesis
Résumé :	The effect of CO2 on Fischer−Tropsch synthesis (FTS) on a cobalt based catalyst had been investigated in a fixed-bed microreactor. Two feed gases, H2:CO:CO2 = 2:1:0 and H2:CO:CO2 = 3:0:1, were mixed in various proportions thus varying the ratio of CO, CO2, and H2 stoichiometrically. The results show that CO and CO2 mixtures can be used as feed to a cobalt catalyst. Comparison of the FTS using different syngas mixtures (CO2/H2, CO2/CO/H2, and CO/H2) shows that: (1) CO2 can be hydrogenated along with CO in the FT reactor over cobalt catalyst, especially in the case of high content of CO2. (2) Hydrogenation of CO2 or CO/CO2 mixture leads to a typical Anderson−Schulz−Flory (ASF) distribution. These could support the hypothesis that CO2 hydrogenation processes might occur with the formation of CO as intermediate. (3) CO feed exhibit the typical two-alpha distribution while CO2 and CO2 rich feeds only exhibit a single-alpha distribution. This may also help us to understand the mechanisms that lead to product distributions in FT with single- and dual-alpha distributions. In spite of the fact that cobalt catalysts are not water−gas shift active, it is shown the rate of hydrocarbon production is maximized at an intermediate composition of the CO/CO2/H2 mixture. The results could have implications for the design of XTL (anything-to-liquids is a process that converts carbon and energy containing feedstock to high quality fuels and products, such as coal-to-liquids, biomass-to-liquids and gas-to-liquids) using cobalt catalysts in that it might be advantageous to keep some carbon dioxide in the syngas feed to the FTS process.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23448002

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 11052–11060

Titre :	A polymer electrolyte hydrogen pump hydrogenation reactor
Type de document :	texte imprimé
Auteurs :	Jay Benziger, Auteur ; James Nehlsen, Auteur
Année de publication :	2011
Article en page(s) :	pp. 11052–11060
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Polymer Electrolyte
Résumé :	Decene and acetone were hydrogenated over Ni, Pd, Pt, Cu, Ag, and Au catalysts in a polymer electrolyte hydrogen pump (PEHP) reactor. Water was oxidized over a Pt mesh anode and protons were pumped to the catalysts supported on porous carbon cathodes in contact with an organic liquid phase. The protons are reduced at the cathode to adsorbed hydrogen atoms which hydrogenate adsorbed olefins and carbonyl groups by heterogeneous catalysis. At low current density decene hydrogenation over Pd and Pt increased with the current density to the 1/2 power, indicating the surface reaction of adsorbed hydrogen with adsorbed decene was the rate limiting step. At high current density the reaction rate decreased linearly with current density, indicating adsorbed hydrogen inhibited decene adsorption and decene adsorption was the rate limiting step. Decene hydrogenation at 50 °C was 100 times slower over Ni, Cu, Ag, and Au catalysts compared to Pd and Pt. Acetone hydrogenation over Pt increased linearly with proton current density and was 10 times slower than decene hydrogenation. Acetone and decene hydrogenation rates at 50 °C were almost the same over Cu catalysts. Data were fit with modified Langmuir−Hinshelwood kinetics; the rate limiting steps were identified as the first hydrogen addition to adsorbed decene and the second hydrogen addition to adsorbed acetone.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie100631a

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 11045-11051

Titre :	Carbon dioxide capture from flue gases using a cross - flow membrane contactor and the ionic liquid 1 - ethyl - 3 - methylimidazolium ethylsulfate
Type de document :	texte imprimé
Auteurs :	Jonathan Albo, Auteur ; Patricia Luis, Auteur ; Angel Irabien, Auteur
Année de publication :	2011
Article en page(s) :	pp. 11045-11051
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Ionic liquid Crossflow Carbon dioxide
Résumé :	Carbon dioxide (CO2) emissions have to be controlled and reduced in order to avoid environmental risks. Membrane processes in combination with the use of ionic liquids are recently under research and development in order to demonstrate a zero solvent emission process for CO2 capture. In this work, the application of a cross-flow membrane contactor is studied for CO2 absorption when the ionic liquid 1-ethyl-3-methylimidazolium ethylsulfate is used as solvent. A mathematical model considering a parallel flow configuration is applied for a cross-flow system in order to describe the mass transfer rate. At a macroscopic level, Koveralla is calculated considering different mixing models corresponding to plug flow and continuous stirred models and a first order mass transfer rate. A microscopic model based on laminar flow has been applied, obtaining a membrane mass transfer coefficient of km = 3.78 × 10―6 m•s ', which is about five times higher than that obtained in the macroscopic model. The interfacial area, a, allows the comparison of efficiencies between cross-flow and parallel membrane contactor systems in terms of the product (Koveralla).
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23448000

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 11037-11044

Titre :	Hydrogen production via chemical looping steam reforming in a periodically operated fixed - bed reactor
Type de document :	texte imprimé
Auteurs :	Rahul D. Solunke, Auteur ; Gotz Veser, Auteur
Année de publication :	2011
Article en page(s) :	pp. 11037-11044
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Fixed bed reactor Steam reforming Hydrogen production
Résumé :	Chemical-looping steam reforming (CLSR) is a chemical-looping combustion (CLC) derived technology in which air is replaced by steam as oxidant. CLSR combines the inherent CO2 capture of CLC with the production of PEMFC-ready hydrogen streams without further purification steps. CLSR thus results in strong process intensification in hydrogen production. Here, we present results from a proof-of-concept study of CLSR of synthesis gas which combines thermodynamic screening for carrier selection, with synthesis and reactive test of highly active and high-temperature stable nanostructured oxygen carriers, and a reactor modeling study in order to demonstrate the feasibility of CLSR in a periodically operated fixed-bed reactor.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447999

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 11029-11036

Titre :	Combustion of Single Coal Char Particles under Fluidized Bed Oxyfiring Conditions
Type de document :	texte imprimé
Auteurs :	Fabrizio Scala, Auteur ; Riccardo Chirone, Auteur
Année de publication :	2011
Article en page(s) :	pp. 11029-11036
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Fluidized bed Fluidization Coal Combustion
Résumé :	The fluidized bed combustion of single coal char particles was investigated at high CO2 concentrations, typical of oxyfiring conditions, at different bed temperatures and oxygen concentrations. The conversion rate of the char particles was followed as a function of time by continuously measuring the outlet CO and O2 concentrations. Char gasification tests were also carried out under 100% CO2 at different temperatures to quantify the importance of this reaction and to extract a suitable kinetic expression. This expression was then combined with a correlation for the mass transfer controlled particle burning rate to simulate the experimental conversion rate data. The calculated carbon consumption rate was an excellent fit to the experimental data for all the operating conditions. Results showed that carbon combustion dominates particle conversion at high oxygen concentrations and low temperatures, while carbon gasification contributes to a comparable extent at high temperatures and low oxygen concentrations. Even under fluidized bed oxyfiring conditions oxygen boundary layer diffusion controls the combustion rate, and the main combustion product is CO2 rather than CO.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447998

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 11018-11028

Titre :	Techno - economic analysis of coal - based hydrogen and electricity cogeneration processes with CO2 capture
Type de document :	texte imprimé
Auteurs :	Fanxing Li, Auteur ; Liang Zeng, Auteur ; Liang-Shih Fan, Auteur
Année de publication :	2011
Article en page(s) :	pp. 11018-11028
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Carbon dioxide Cogeneration Coal Economic analysis
Résumé :	The techno-economic performances of various coal-based hydrogen and electricity cogeneration processes are examined under a carbon-constrained scenario. The baseline coal gasification process and the novel membrane and syngas chemical-looping processes are evaluated. Aspen Plus simulation is first performed to analyze the process efficiencies on the basis of a common set of assumptions. This is followed by economic analysis using the cost analysis principles suggested by the U.S. Department of Energy [Cost and Performance Baseline for Fossil Energy Plants, 2007]. The results indicate that the novel membrane and syngas chemical-looping strategies have the potential to notably reduce the energy and cost penalties for CO2 capture in coal conversion processes.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447997

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 11009–11017

Titre :	Reduction kinetics of la modified NiO / La - γAl2O3 oxygen carrier for chemical - looping combustion
Type de document :	texte imprimé
Auteurs :	Mohammad M. Hossain, Auteur ; Mohammad R. Quddus, Auteur ; Hugo I. Lasa, Auteur
Année de publication :	2011
Article en page(s) :	pp. 11009–11017
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Kinetics Oxygen Combustion
Résumé :	La modified Ni/La-γAl2O3 oxygen carrier reduction kinetics is investigated using temperature programmed reduction (TPR) and a parameter nonlinear regression analysis. TPR profile study and XRD analysis of the completely oxidized samples show that NiO is the prevalent phase of the oxygen carrier. Hydrogen pulse chemisorption demonstrates that the nickel crystallite sizes remain unchanged over repeated reduction/oxidation cycles. A nucleation and nuclei growth model and an unreacted shrinking core model are developed based on the oxygen carrier characterization. Model discrimination is conducted based on SSQ, goodness of fittings, and minimum cross-correlation coefficients. On the basis of these statistical indicators, it is established that the random nucleation model describes the reduction of the oxygen carrier adequately. The estimated value of the activation energy for the La modified Ni/La-γAl2O3 sample is found to be 73.4 ± 2.6 kJ/mol, with this being significantly lower than the activation energy for the unmodified Ni/γAl2O3 sample (104.5 ± 3 kJ/mol). This suggests that the unmodified oxygen carrier requires higher activation energy, with this reflecting an increased difficulty of nickel phase reduction due to a strong interaction between nickel and alumina. The nucleation model, as established using TPR, is successfully validated for the reduction cycle using methane as a fuel gas in a CREC minifluidized riser simulator reactor operating under the expected operating conditions for large industrial scale chemical-looping combustion (CLC) units.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie100424w

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 11001-11008

Titre :	Modeling impregnated layer combustion synthesis of catalyts for hydrogen generation from oxidative reforming of methanol
Type de document :	texte imprimé
Auteurs :	A. Kumar, Auteur ; A. S. Mukasyan, Auteur ; E. E. Wolf, Auteur
Année de publication :	2011
Article en page(s) :	pp. 11001-11008
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Reforming Oxidation Hydrogen production Combustion Modeling
Résumé :	A novel method for catalyst preparation using combustion synthesis techniques has been used to prepare Cu/Zn/Zr and Pd-based catalysts for oxidative reforming of methanol. Spatially resolved infrared thermography has been used to follow the temperature-time movement of the combustion front on cellulose paper impregnated with the catalyst precursor solution along with other techniques to follow the systematic evolution of the catalyst particles from the initial reactants mixture. These particles have been characterized by their activity/selectivity for methanol oxidation/hydrogen production, BET area, and dispersion of Pd on the surface. Results obtained show that they are extremely active and selective in the low temperature range. A one-dimensional theoretical model is presented that describe the main parameters involved in the front propagation.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447995

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10994–11000

Titre :	Hydrogen for vehicle applications from hydrothermolysis of ammonia borane : Hydrogen yield, thermal characteristics, and ammonia formation
Type de document :	texte imprimé
Auteurs :	Hyun Tae Hwang, Auteur ; Ahmad Al-Kukhun, Auteur ; Varma, Arvid, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10994–11000
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Hydrogen Hydrothermolysis
Résumé :	Among chemical hydrides, ammonia borane (AB) is of interest as a hydrogen storage material due to its high hydrogen capacity (19.6 wt %). In this paper, our recently developed hydrothermolysis process was investigated over a wide range of AB weight percentages (wt %) in water, pressures, and heating rates. It was found that hydrogen yield and thermal characteristics were influenced by these operating conditions. Ammonia generation was also observed during AB hydrothermolysis, where 14−53% of AB was converted to NH3 depending on the reaction conditions. It is remarkable that some AB (2−4%) was converted to NH3, which must be removed for use in proton exchange membrane (PEM) fuel cells, even by neat thermolysis. It was also found that during the hydrothermolysis reaction at Treactor of 85 °C, the Tsample can exceed 500 °C, where AB can be completely decomposed to boron nitride (BN). The 11B NMR characterization of hydrothermolysis products showed compounds with B−O and B−N bonds. This paper suggests directions for future research to identify optimal conditions, where the hydrothermolysis process provides the best balance between H2 yield and undesirable products, for PEM fuel cell vehicle applications.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie100520r

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp 10986–10993

Titre :	Process Intensification in Hydrogen Production from Biomass-Derived Syngas
Type de document :	texte imprimé
Auteurs :	Mitra Abdollahi, Auteur ; Jiang Yu, Auteur ; Hyun Tae Hwang, Auteur
Année de publication :	2011
Article en page(s) :	pp 10986–10993
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Biomass Hydrogen
Résumé :	Biomass is a renewable and worldwide-abundant energy resource that shows great potential for environmentally benign power generation by minimizing greenhouse gas emissions. A “one-box” process has been proposed and studied in order to economically produce pure hydrogen from biomass-derived syngas in the presence of its common impurities through the use of the water gas shift (WGS) reaction. The heart of the process is a catalytic membrane reactor making use of carbon molecular sieve (CMS) membranes and an impurity-tolerant commercial Co/Mo/Al2O3 catalyst. CMS membrane stability was investigated in the presence of model tar and organic vapor compounds at experimental conditions similar to the WGS reaction environment. Experimental studies were carried out utilizing simulated biomass-derived syngas containing H2S and NH3 as key impurities, which was fed into the catalytic membrane reactor to produce a contaminant-free hydrogen product using the WGS reaction. The reactor performance has been investigated for various experimental conditions, and has been compared with simulation results from a mathematical model. The model was also used to study the effect of various parameters on system performance. A key observation is that both the membranes and the catalyst show satisfactory stability in the presence of impurities typically encountered in biomass-derived syngas, and that the system shows good performance, delivering higher CO conversion and hydrogen purity than when using a traditional reactor system.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie100620e

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10981-10985

Titre :	Catalytic Steam and Autothermal Reforming of Used Lubricating Oil (ULO) over Rh- and Ni-Based Catalysts
Type de document :	texte imprimé
Auteurs :	U. Wetwatana, Auteur ; P. Kim-Lohsoontorn, Auteur ; S. Assabumrungrat, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10981-10985
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Catalyst Lubricating oil Autothermic reactor Reforming Water vapor Catalytic reaction
Résumé :	The steam reforming of used lubricating oil (ULO) over Ni- and Rh-based catalysts supported by Ce-ZrO2 and Al2O3 is studied in the present work. Among all catalysts, Rh/Ce-ZrO2 (5 wt % Rh) provides relatively higher reforming reactivity (in terms of ULO conversion and H2 yield) with excellent resistance toward carbon deposition compared to the other three catalysts. At 850 °C after exposure in the steam reforming condition for 72 h, H2 yield of 78.1% can be achieved from the reaction over Rh/Ce-ZrO2. For Ni/Ce-ZrO2 and Ni/ Al2O3, significant deactivations with time are detected and H2 yields of 55.3―58.7% are achieved after exposure for 72 h; in addition, considerable amounts of C2H4, C2H6 and C3H6 are also found in the product along with H2, CO, CO2, and CH4. The effect of O2 addition was further studied over Ni/Ce-ZrO2 and Ni/Al2O3. It was found that this addition significantly reduces the degree of carbon deposition as well as promoting the conversion of hydrocarbons to CO and H2. At a suitable amount of O2, a high H2 yield comparable to that of steam reforming over Rh-based catalysts can be achieved. Nevertheless, it must be noted that introducing too high an O2 content resulted in lower H2 production due to the combustion of H2 and ULO by O2 addition.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447992

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10974-10980

Titre :	Hydrogen production by SCWG treatment of wastewater from amino acid production process
Type de document :	texte imprimé
Auteurs :	In-Gu Lee, Auteur ; Son-Ki Ihm, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10974-10980
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Manufacturing process Waste water Hydrogen production
Résumé :	The organic wastewater obtained from an amino acid production process was treated by supercritical water gasification (SCWG) method for achieving water purification and hydrogen production. A set of SCWG experiments was also carried out with glucose and valine solutions as model compounds for reducing sugars and amino acids present in the wastewater, respectively. The effect of temperature (600—700 °C) and different catalysts (activated charcoal (AC), Ni/AC, and Ni―Y/AC) on the extent of gasification and gas composition was investigated in a continuous-flow reactor at 28 MPa and 12 h―1 LHSV. Complete gasification of organic compounds in the wastewater was achieved in the presence of the supported nickel catalysts, resulting in the formation of gaseous products with high hydrogen contents. Alkaline salts present in the wastewater feed contributed to hydrogen formation reactions. Solid product formed during the SCWGs of the wastewater feed was identified as one of main obstacles for a possible commercial design and a schematic concept was suggested for its removal.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447991

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10965–10973

Titre :	Hybrid quantum mechanics / molecular mechanics investigation of (salen) Mn for use in metal − organic frameworks
Type de document :	texte imprimé
Auteurs :	Gloria A. E. Oxford, Auteur ; Randall Q. Snurr, Auteur ; Linda J. Broadbelt, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10965–10973
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Hybrid mechanics catalysts
Résumé :	Hybrid quantum mechanics/molecular mechanics (QM/MM) methods were employed to study electronic effects of 5,5′-substituents on the enantioselectivity of (salen)Mn catalysts. These methods were shown to effectively capture electronic effects of substituents if the substituents were treated with a simple electrostatic coupling using point charges. Correlations between calculated properties of (salen)Mn═O indicative of its reactivity and the modified Hammett constant σpara+ were applied to study electronic framework effects on enantioselectivity for (salen)Mn heterogenized in a metal−organic framework (MOF). The results suggest that these effects are too small to account for all of the decrease in enantioselectivity observed experimentally and that steric constraints of the framework likely play a role. The reactivity correlations also enabled fast ligand screening for the prediction of highly enantioselective (salen)Mn catalysts that could be used in MOFs. A modified version of the DREIDING force field was also developed to allow QM/MM calculations of (salen)Mn species.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie100165j

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10956-10964

Titre :	Influence of two - dimensional distribution schemes upon reactor performance in a ceramic microchannel network for autothermal methanol reforming
Type de document :	texte imprimé
Auteurs :	Angela M. Moreno, Auteur ; Shalini Damodharan, Auteur ; Benjamin Wilhite, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10956-10964
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Reforming Ceramic materials Reactor
Résumé :	In this work, the authors design, fabricate, and evaluate three prototype ceramic microchannel reactor architectures with two-dimensional complex flow configurations for coupling methanol steam reforming with methanol combustion/partial oxidation. These prototypes were evaluated for the autothermal hydrogen production from methanol in order to investigate the influence of individual process flow rates and radial distribution schemes upon thermal gradients and overall system performance in the absence of any external insulation. Results demonstrate that, in the case of low thermal conductivity ceramic substrates, appropriate selection of two-dimensional radial distribution patterns enables the tailoring of one- and three-dimensional thermal gradients for enhancing self-insulating qualities of the microchannel reactor as well as enhancing overall hydrogen yields.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447989

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10942-10955

Titre :	Scale - out of microreactor stacks for portable and distributed processing : Coupling of exothermic and endothermic processes for syngas production
Type de document :	texte imprimé
Auteurs :	Matthew S. Mettler, Auteur ; Georgios D. Stefanidis, Auteur ; Dionisios G. Vlachos, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10942-10955
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Production Synthesis gas Microreactor
Résumé :	Computational fluid dynamics (CFD) simulations are used to simulate stacks of different sizes, to understand nonlinear effects that arise in scaleout of microchemical systems. As an example process, syngas production from methane is studied using a multifunctional, parallel-plate reactor with alternating combustion and steam reforming channels. A scale-out strategy is proposed that creates larger stacks from a base unit. Stacks are evaluated in terms of efficiency, maximum wall temperature, and stability under external heat loss for both high and moderate wall thermal conductivities. We find that smaller stacks are unstable under laboratory heat-loss conditions. Stacks with high wall thermal conductivities are more stable than those with moderate wall conductivities under our conditions. At high heat-loss coefficients, significant transverse thermal gradients exist between interior and edge channels of the stacks that result in a significant loss of efficiency. A transition from all ignited to some ignited and extinguished and finally to all extinguished channels is discovered as criticality is approached in moderate size stacks. Microsystems provide 1-3 orders of magnitude larger volumetric and gravimetric throughputs than conventional technology, irrespective of model uncertainty, and such intensification is central to portable and distributed processing. They exhibit energy efficiency that is a strong function of size and heat loss but can outperform conventional processing under many conditions. However, they result in higher cost per unit syngas volume unless system optimization is performed.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447988

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10934-10941

Titre :	Preparation and performance of a catalyst - coated stacked foil microreactor for the methanol synthesis
Type de document :	texte imprimé
Auteurs :	Xuyen K. Phan, Auteur ; Hamidreza D. Bakhtiary, Auteur ; Rune Myrstad, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10934-10941
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Microreactor Catalyst Preparation
Résumé :	A stacked foil microreactor (SFMR) was developed and used to study methanol synthesis under high pressure. Two catalyst foil coatings were applied: Pd/CeO2 by sol―gel coating and impregnation and CuO/ZnO/Al2O3 by coprecipitation and slurry coating. Laboratory fixed-bed reactor (FBR) experiments were made for comparison. The results show that active foil coatings of both Pd/CeO2 and CuO/ZnO/Al2O3 can be prepared. The activity of Pd/CeO2 coated foils is significantly better than Pd/CeO2 particles prepared by deposition-precipitation. The differences found between the two reactor types using the same Cu catalyst can be partly related to heat exchange properties.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447987

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10924-10933

Titre :	Micro - scale catalytic reactor for syngas production
Type de document :	texte imprimé
Auteurs :	S. Vaccaro, Auteur ; L. Malangone, Auteur ; P. Ciambelli, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10924-10933
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Production Synthesis gas Catalytic reactor
Résumé :	This paper presents both experimental and modeling investigations of a catalytic wall fuel processor consisting of coupled methane reforming and methane combustion sections. The reacting systems are both catalytic and the latter generates the heat required for the occurrence of the former. The catalytic wall reactor was examined for light-off behavior and for steady-state product distribution. On one hand, the analysis of the reaction products distribution after catalyst ignition indicated that in both combustion and reforming sections catalysts undergo to a relatively long transient (about 40 min) before reaching steady state conditions. On the other hand, a much longer reactor thermal transient was observed and the two transient behaviors appear independent of each other. Analysis of the reactor operating under real conditions (nonadiabatic) showed that a 3D model is needed to accurately predict the reactor performance because a 2D model, although much more convenient, cannot allow for the whole heat loss thereby yielding unreliable results.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447986

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10917-10923

Titre :	Investigation on the combined operation of water gas shift and preferential oxidation reactor system on the kW scale
Type de document :	texte imprimé
Auteurs :	Martin O’Connell, Auteur ; Gunther Kolb, Auteur ; Karl-Peter Schelhaas, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10917-10923
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Reactor Oxidation Water gas
Résumé :	A 5 kWel water gas shift reactor was integrated with a 5 kWel preferential oxidation reactor for the purposes of reducing the carbon monoxide levels in a reformate exit stream to levels below 100 ppm. The integrated system worked best at partial load with CO concentrations being reduced to 40 ppm at 60% load level and S/C = 3.2.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447985

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10908-10916

Titre :	Design and control techniques for the numbering - up of capillary microreactors with uniform multiphase flow distribution
Type de document :	texte imprimé
Auteurs :	Matthias Mendorf, Auteur ; Henrik Nachtrodt, Auteur ; Axel Mescher, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10908-10916
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Flow field Multiphase flow Microreactor Design
Résumé :	The results of experimental studies on the parallelization of both single-phase and biphasic liquid-liquid slug flow in capillary microreactors are presented. Various flow distributor designs were investigated with respect to the uniformity of liquid-liquid flow in eight parallel capillaries and the two most promising concepts were identified. A novel multichannel phase splitting unit was installed at the downstream end of the capillaries to ensure well-defined phase separation. Further investigations on more complex reaction systems, in which the hydrodynamics depend on conversion and/or selectivity (e.g., polymerization), suggest that an active flow control for individual capillaries will be necessary in such cases. The uniformity of flow rate and flow structure could be achieved using a noninvasive capacitative measurement to characterize the flow in conjunction with specially developed microvalves and actuators for the regulation of flow rates and the manipulation of slug flow structure in each capillary.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447984

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10897–10907

Titre :	Ethylene oxide formation in a microreactor : From qualitative kinetics to detailed modeling
Type de document :	texte imprimé
Auteurs :	Jose R. Hernandez Carucci, Auteur ; Ville Halonen, Auteur ; Kari Eranen, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10897–10907
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Microreactor Kinetics
Résumé :	Silver/α-alumina catalysts were wash-coated in stainless steel microchannels. The microchannels were used for the epoxidation of ethylene. Pure silver microplates were also investigated giving the highest activities and selectivities toward the ethylene oxide formation. Pretreatment conditions with oxygen and ethylene for the pure silver catalyst were studied and optimized. The experiments were carried out under atmospheric pressure, varying the temperature from 220 to 300 °C and the total gas flow from 5.4 to 10.5 cm3/min. A precise kinetic model for the ethylene oxide formation in pure silver microchannels was developed at 260 °C. The model was based on the competitive adsorption of ethylene and molecular oxygen over the silver surface. The concentrations of the reactants (oxygen and ethylene) in the gas flow were systematically varied from 5 to 25 vol % using helium gas as balance. The model was confronted with experimental data obtained in the microchannels, resulting in a very high degree of explanation (97%).
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie100521j

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10889-10896

Titre :	Thermographic investigations of a microstructured thin film reactor for gas / liquid contacting
Type de document :	texte imprimé
Auteurs :	Kristin Hecht, Auteur ; Manfred Kraut, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10889-10896
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Reactor Thin film
Résumé :	A new microstructured thin film reactor that allows for thermographic imaging of the reaction through the thin metal foil along which the liquid flows has been studied with the exothermic absorption of CO2 into aqueous solutions of NaOH. The usefulness of the new method is demonstrated on the extreme differences in temperature obtained for reaction with dry CO2 compared to reaction with prehumidified CO2. The method is able to follow the reaction in a case where complete conversion is reached before the reactor's end, meaning that the reaction rate changes drastically from a fast beginning to zero at the end. Concentration and liquid transport coefficient profiles can be derived from the measurements obtained with this method. The information obtained indicates that this method can become a useful tool in the study of gas/liquid reactions because the measurements obtained along the length of the reactor allow for a better analysis than those obtained from an integral analysis of the reactor.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447982

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10883–10888

Titre :	Scale - up of microchannel reactors for fischer − tropsch synthesis
Type de document :	texte imprimé
Auteurs :	Soumitra R. Deshmukh, Auteur ; Anna Lee Y. Tonkovich, Auteur ; Kai T. Jarosch, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10883–10888
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Microchannel reactors
Résumé :	The scale-up of a microchannel reactor for Fischer−Tropsch (FT) synthesis has been demonstrated at multiple scales using four reactors with different lengths and number of channels. An FT catalyst provided by Oxford Catalysts, Ltd. was tested in single channel microreactors with catalyst bed length ranging from 4 to 62 cm. The same catalyst was also tested in a pilot reactor with 276 parallel process channels (17 cm in length). Equivalent process performance was observed across each scale as determined by the metrics of CO conversion, selectivity to byproduct, and the chain growth probability (α). The overall C5+ productivity for these reactors of disparate scales spanned several orders of magnitude ranging from 0.004 gallons per day (GPD) to 1.5 GPD. The operational flexibility of these microreactors was illustrated by varying syngas feed composition and flow sheet conditions (pressure, temperature, dilution, etc.). The elusive premise of numbering up microchannels has been demonstrated, enabling the scale-up of reactor capacity.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie100518u

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10876–10882

Titre :	Selective oxidation of glycerol to dihydroxyacetone over Pt − Bi / C catalyst : Optimization of catalyst and reaction conditions
Type de document :	texte imprimé
Auteurs :	Wenbin Hu, Auteur ; Daniel Knight, Auteur ; Brian Lowry, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10876–10882
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Optimization Catalyst Oxidation
Résumé :	Glycerol selective oxidation to dihydroxyacetone was investigated systematically in a semibatch reactor over Pt−Bi/C catalyst. Catalysts with different metal loadings, supports, and preparation methods were synthesized, characterized, and tested. The sequential impregnation of Pt and then Bi, followed by NaBH4 reduction, was the optimum synthesis method for high glycerol oxidation rate and maximum DHA yield. The optimum catalyst composition was determined to be 3 wt % Pt, 0.6 wt % Bi, supported on Norit Darco 20-40 mesh activated carbon (BET surface area 600 m2/g, average pore size 4 nm, average pore volume 0.53 cm3/g). In addition to the catalyst, the reaction conditions were also optimized by conducting experiments in the range of temperature 30−90 °C, oxygen pressure 0−180 psig, and initial pH 2−12. The optimum reaction conditions were identified as 80 °C, 30 psig, and initial pH = 2. Under these conditions, a maximum DHA yield of 48% was obtained at 80% glycerol conversion. The catalysts were characterized by using BET, ICP-OES, TEM, XRD, and XPS techniques.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447980

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10859–10875

Titre :	Biomass - based fuel cell power plants : Evaluation of novel reactors and process designs
Type de document :	texte imprimé
Auteurs :	Peter Heidebrecht, Auteur ; Benny Hartono, Auteur ; Christoph Hertel, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10859–10875
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Biomass Fuel cell
Résumé :	This contribution focuses on the model-based system design and the systemwide evaluation of novel reactor concepts for power plants which combine gasification of wood and conversion of its gaseous product in fuel cells. System design was carried out with the help of a model library, which contains models of all reactor units under consideration. Each system was subject to several feasibility checks, and optimization of the most important control parameters was performed. Simulation results show that high temperature gas purification units and high temperature proton exchange membrane fuel cells have strong advantages over their classical counterparts with respect to heat integration and electrical system efficiency. Systems with high and low temperature fuel cells were studied separately, but they show that a combination of both types of fuel cells in a single plant offers the highest efficiency and attractive flexibility with respect to electricity and heat production.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie100408n

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10852–10858

Titre :	Supercritical deoxygenation of a model bio - oil oxygenate
Type de document :	texte imprimé
Auteurs :	Jackson W. Ford, Auteur ; Raghunath V. Chaudhari, Auteur ; Bala Subramaniam, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10852–10858
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Deoxygenation Oil
Résumé :	A novel process for the fixed-bed deoxygenation of a model bio-oil compound in supercritical media at mild pressures (tens of bars) is presented. As an example, nonanal deoxygenation over Pt/Al2O3 catalyst in supercritical n-hexane (Tc = 234.45 °C, Pc = 30.2 bar) with excess hydrogen (molar H2/nonanol in feed = 57) at 300 °C provides steady conversions of approximately 60% over a pressure range of 7−80 bar with approximately 40% selectivity to C8 and C9 hydrocarbons, at liquid hourly space velocities of 80 g nonanal·(g Pt)−1·h−1. Further, the conversions display only a mild temperature dependence. This suggests that for the conditions under study, the reaction is limited by mass transfer of nonanal (limiting reactant) from the bulk fluid phase to the catalyst particle. Among the alkanes, the selectivity to the decarbonylation product (n-octane) is higher at all pressures relative to the hydrogention product (n-nonane). However, the selectivities toward nonane and nonanol increase relative to the decarbonylation product (n-octane) at higher reactor pressures, attributed to the enhanced hydrogen partial pressures at supercritical conditions. Effective rate constants, estimated from a simple isothermal packed-bed reactor model that assumes first-order dependence on nonanal concentration, decrease exponentially as the pressure is tuned from subcritical pressures (gaslike properties) to supercritical pressures (liquidlike properties). This decrease is characteristic of the pressure dependence of the external mass transfer coefficient. Mass transfer coefficients, predicted using published correlations, are of the same order of magnitude as the effective rate constants, further affirming that the measured reaction rates are controlled by external mass transfer.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie1005492

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10845–10851

Titre :	Pyrolysis using microwave heating : A sustainable process for recycling used car engine oil
Type de document :	texte imprimé
Auteurs :	Su Shiung Lam, Auteur ; Alan D. Russell, Auteur ; Howard A. Chase, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10845–10851
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Microwave Engine Oil
Résumé :	We demonstrate the applicability of pyrolysis using microwave heating to recycle used car engine oil. Waste oil was thermally cracked in an inert microwave-heated bed of particulate carbon from which oxygen was excluded, and the relationship between temperature, the chemical composition of the hydrocarbons, and the metal fraction produced was determined. A reaction temperature of 600 °C provided the greatest yield of commercially valuable products: the recovered liquid oils were composed of light paraffins and aromatic hydrocarbons that could be used as industrial feedstock; the remaining incondensable gases comprised light hydrocarbons that could potentially be used as a fuel source to power the process. In addition, the recovered liquid oils showed a significant reduction in the metal contaminants accumulated throughout their use cycle: a 93−97% reduction in Cu, Ni, Pb, Zn, Fe; a 46% reduction in Cd; and a 32% reduction in Cr. Our results indicate that microwave pyrolysis shows exceptional promise as a means for recycling and treating problematic waste oil.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie100458f

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10836–10844

Titre :	Kinetic Model for the Transformation of Bioethanol into Olefins over a HZSM-5 Zeolite Treated with Alkali
Type de document :	texte imprimé
Auteurs :	Ana G. Gayubo, Auteur ; Ainhoa Alonso, Auteur ; Beatriz Valle, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10836–10844
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Kinetic Bioethanol Zeolite
Résumé :	A kinetic model for the transformation of bioethanol (aqueous ethanol into hydrocarbons) has been established for a catalyst with slow deactivation by coke (prepared from a HZSM-5 zeolite treated with alkali in order to moderate its acid strength and generate mesopores in the zeolite structure). The kinetic model allows quantifying the distribution of the lumps of products (ethylene, C3−C4 olefins, gasoline or C5−C10, and C1−C3 paraffins) and is particularly interesting for quantifying the production of C3−C4 olefin lump, which is the one of greater commercial interest. The experimental data have been obtained in an isothermal fixed-bed reactor in a wide range of operating conditions (temperature of 300−400 °C, space time and water content in the feed). The remarkable features of the kinetic model are (i) consideration of the autocatalytic formation of C3−C4 olefin lump following their reaction with ethylene, (ii) consideration of the combined involvement of ethylene and the light olefin lump in the formation of heavier hydrocarbons; and (i) quantification of the effect of water in the reaction medium, which attenuates the rate of each one of the steps in the kinetic scheme, except the dehydration of ethanol which is instantaneous under these conditions.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie100407d

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10826-10835

Titre :	Kinetic modeling of aqueous - phase glycerol hydrogenolysis in a batch slurry reactor
Type de document :	texte imprimé
Auteurs :	Arely Torres, Auteur ; Debdut Roy, Auteur ; Bala Subramaniam, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10826-10835
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Modeling Particle suspension Reactor Batchwise Hydrogenolysis Kinetic model
Résumé :	The kinetics of the aqueous-phase hydrogenolysis of glycerol to 1,2-propanediol (1,2-PDO) was studied using a bimetallic Ru―Re/C catalyst in a slurry reactor in a temperature range of 493-513 K and a hydrogen pressure of 2.4-9.6 MPa. Glycerol hydrogenolysis to produce 1,2-PDO via C―O cleavage (i) proceeds with parallel C—C cleavage, reforming, water-gas shift, and Fischer-Tropsch reactions, (ii) results in a very complex reaction network with several gaseous- and liquid-phase products, and (iii) poses a challenge to design selective catalysts. It is observed that Ru―Re bimetallic catalyst shows higher hydrogenolysis activity (glycerol conversion of X = 57.7%) and 1,2-PDO selectivity (S = 36.6%), compared to the monometallic Ru catalyst (X = 52.1%; S = 18.9%) but the monometallic Re catalyst showed no catalytic activity for the reaction. Stirred-batch reactor data on the transient concentrations of reactants and products in both the gas and liquid phases were obtained using a bimetallic Ru-Re/C catalyst under different conditions to understand the reaction pathways, selectivity behavior, and intrinsic kinetics of the different reaction steps. For kinetic modeling, several experiments were performed at different initial pressures of hydrogen, catalyst concentration, and temperatures. The proposed rate equations, along with the regressed kinetic and activation energy parameters, were found to represent the experimental data for the multistep hydrogenolysis reaction very satisfactorily.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447975

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10818-10825

Titre :	Mixing effects in cellulase - mediated hydrolysis of cellulose for bio - ethanol production
Type de document :	texte imprimé
Auteurs :	Saikat Chakraborty, Auteur ; Ashwin Gaikwad, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10818-10825
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Production Hydrolysis Mixing
Résumé :	Conversion of cellulose to glucose is the rate-limiting step in converting biomass into fuel. In this paper, we explore the effects of micro- and macro-mixing on the enzymatic hydrolysis of various cellulosic substrates to glucose by using a spatially averaged low-dimensional CSTR model. We quantify the effects of mixing on glucose yield, cellulose depolymerization rate and the synergy between the enzymes. We conclude that micromixing limitations provide an important mechanism to increase yield, reduce the dominance of synergy and guide optimum process design by offsetting inhibitory effects by preventing the inhibitors from coming in contact with the enzymes. On quantifying the effects of inhibition type (competitive vs noncompetitive) and mixing type (macro- vs micro-), we find that noncompetitive inhibition inhibits glucose yield more strongly than competitive inhibition, and that unlike micromixing limitations, macromixing limitations reduce glucose yield. On the basis of our analysis, we recommend 2 tank reactors in series with minimal local mixing in each tank and glucose removal at the exit of the first tank as the optimal reactor configuration for maximizing glucose yield from enzymatic hydrolysis of cellulose.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447974

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10804–10817

Titre :	Glycerol steam reforming over bimetallic Co − Ni / Al2O3
Type de document :	texte imprimé
Auteurs :	Cheng Chin Kui, Auteur ; Say Yei Foo, Auteur ; Adesoji A. Adesina, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10804–10817
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Glycerol Bimetallic
Résumé :	Glycerol steam reforming has been performed in a fixed-bed microreactor containing bimetallic Co−Ni/Al2O3 catalyst using a wide range of steam-to-glycerol ratios (3 ≤ STGR ≤ 12) for reaction temperatures between 773 and 823 K at atmospheric pressure. Physicochemical characterization revealed the presence of both Lewis and Brönsted acid sites on the catalyst although the catalyst appears to have a net surface acidity (acid:basic site concentration ratio = 9.0). Co and Ni oxides as well as the metal aluminates were identified from XRD pattern with crystallite size (131.5 nm) similar to that obtained from H2 chemisorption experiments (136.0 nm). Glycerol consumption rate data analysis implicates fractional orders with respect to both glycerol (0.25) and steam (0.36) with an activation energy of 63.3 kJ mol−1. Similar treatment for H2, CO2, CO, and CH4 production rate evinced positive fractional orders for both reactants with the exception of CO which has mild inhibition by steam (−0.065). Mechanistic considerations and associated Langmuir−Hinshelwood and Eley−Rideal kinetic models were derived for both single- and dual-site adsorption modes. However, statistical discrimination as well as thermodynamic evaluation of the associated parameter estimates suggest that the most adequate representation involved molecular adsorption of glycerol and steam on two different sites with surface reaction as the rate-controlling step consistent with the presence of both Brönsted acid and basic sites on the catalyst. Carbon deposition during reaction appeared to be responsible for the loss in surface area and pore volume of the used catalysts. However, these attributes were nearly recovered after regeneration (>90%) using TPR−TPO−TPR−TPO cycles. Significantly, carbon deposition is a strong function of glycerol partial pressure but somewhat insensitive to the presence of steam, suggesting that the carbon residue was probably unreactive with steam under the reaction conditions. Indeed, temperature-programmed heat treatment (TPO−TPR−TPO−TPR and TPR−TPO−TPR−TPO) revealed at least two types of carbonaceous deposits. However, one of these carbon pools was resistant to removal with H2.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie100462t

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10798-10803

Titre :	Effect of electromagnetic field on three - phase flow behavior
Type de document :	texte imprimé
Auteurs :	Ze Sun, Auteur ; Ping Li, Auteur ; Guimin Lu, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10798-10803
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Three phase flow
Résumé :	The multiphase transport phenomena frequently take place in metallurgical processes, for example, in the electrolysis process of magnesium, where there exists three-phase flow including liquid magnesium, molten electrolyte, and chlorine gas under the electromagnetic field. In this paper, the three-phase flow behaviors under the electromagnetic field in the advanced diaphragmless electrolytic cell were investigated by CFD simulation. The governing equations of the internal flow field in the electrolytic cell were established, where the standard k-e turbulence model and the VOF multiphase flow model were adopted for the comprehensive description of the flow characteristics of multiphase flow in the electrolytic cell, and the Lorentz force was added to the momentum equation of fluids as the momentum source term to combine the effect of electromagnetic field with the flow field. The order coupling method was adopted for the calculation of the coupled field. The numerical simulation on the three-phase flow field considering the effect of electromagnetic field was done using FLUENT6.3 software, the numerical simulations on the electric field and the magnetic field were carried out using Ansys 11.0 software, respectively, and the connection between the finite element software ANSYS and the control volume software Fluent was built using the user-defined function (UDF). According to the analysis on the distributions of the electromagnetic field and the flow field, the optimum flow circulation in the advanced diaphragmless electrolytic cell was obtained, which is very helpful for the design in the electrolysis process of molten magnesium salt.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447972

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10780-10797

Titre :	Toward a truly multiscale computational strategy for simulating turbulent two - phase flow processes
Type de document :	texte imprimé
Auteurs :	E.A. Harry, Auteur ; Akker Van Der, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10780-10797
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Turbulent Phase flow
Résumé :	In chemical reactor engineering, simple concepts are used for describing the flow in a reactor. Turbulent two-phase flow processes, however, are characterized by a broad range of time and length scales. Two-phase reactors operated in the turbulent regime therefore qualify for multiscale modeling. Multiscale models are being developed in such diverging fields as chemical reaction engineering (among which are packed bed reactors, fluidized beds, and risers), chemical vapor deposition reactor modeling, turbulent single-phase and two-phase flow simulations (among which is combustion), and materials science. The common aspects of these multiscale models are highlighted: they all comprise a coarse-grained simulation for the macroscale and some type of fully resolved microscale simulation. Different simulation techniques are used however. Processes involving single-phase flow may require one of three computational fluid dynamics (CFD) techniques: direct numerical simulations (DNSs), large eddy simulations (LESs), and Reynolds averaged Navier-Stokes (RANS)-based simulations. For two-phase flows, two CFD options are open: Euler-Lagrangian (or particle tracking) and Euler-Euler (or two-fluid). The characteristics of all these approaches are discussed. One of the more interesting options in dealing with turbulent two-phase, i.e., multiscale, flow reactors is to run a DNS for the local small-scale processes. Such a DNS is carried out in a periodic box, a dedicated forcing technique being
ISSN :	0888-5885
En ligne :	http://www.refdoc.fr/Detailnotice?idarticle=50845921

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10767-10779

Titre :	High - resolution simulations of coal injection in a gasifier
Type de document :	texte imprimé
Auteurs :	Tingwen Li, Auteur ; Aytekin Gel, Auteur ; Madhava Syamlal, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10767-10779
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Coal High resolution
Résumé :	This study demonstrates an approach to effectively combine high- and low-resolution simulations for design studies of industrial coal gasifier. The flow-field data from a 10 million cell full-scale simulation of a commercial-scale gasifier were used to construct a reduced configuration to economically study the coal injection in detail. High-resolution numerical simulations of the coal injection were performed using the open-source code MFIX running on a high performance computing system. Effects of grid resolution and numerical discretization scheme on the predicted behavior of coal injection and gasification kinetics were analyzed. Pronounced differences were predicted in the devolatilization and steam gasification rates because of different discretization schemes, implying that a high-order numerical scheme is required to predict well the unsteady gasification process on an adequately resolved grid. Computational costs for simulations of varying resolutions are presented to illustrate the trade-off between the accuracy of solution and the time-to-solution, an important consideration when engineering simulations are used for the design of commercial-scale units.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447970

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp.10758-10766.

Titre :	Liquid - solid mass transfer in agitated slurry reactors and rotating solid foam reactors
Type de document :	texte imprimé
Auteurs :	R. Tschentscher, Auteur ; R.J.P. Spijkers, Auteur ; T.A. Nijhuis, Auteur
Année de publication :	2011
Article en page(s) :	pp.10758-10766.
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Mass transfer Reactor
Résumé :	The liquid−solid mass transfer rate is studied for two three-phase reactor configurations, a stirred reactor and a rotating solid foam reactor, using the dissolution of copper by potassium dichromate as a model reaction. For the stirred reactor consisting of a Rushton stirrer and a slurry with small particles, the particle density has a large influence on the liquid−solid mass transfer rate. Heavy particles show high slip velocities, as their path is less influenced by the liquid turbulence. Furthermore, the mass transfer is enhanced by neighboring particles passing each other. In the case of solid copper particles, a kLS value of 3 × 10−3 ms−1 was observed. For particles having a density comparable to industrial catalyst supports, the kLS value is 1 order of magnitude lower. For the rotating foam block stirrer also, high kLS values of 2.5 × 10−3 ms−1 could be achieved due to the high liquid velocity along the foam struts. The influence of several parameters on the hydrodynamics and the liquid−solid mass transfer was studied. Among these, the foam block height, the foam pore size, and the space above the foam block stirrer have a large effect on the liquid circulation, the bubble formation, and therefore on the liquid−solid mass transfer. The reduction of the foam pore size has two counterbalancing effects, resulting only in a slight increase of the rate of mass transfer: (i) the liquid−solid interfacial area is increased; (ii) the liquid circulation is, however, reduced due to the higher frictional pressure drop. Gas bubbles passing the foam struts affect the liquid−solid mass transfer by inducing liquid velocity fluctuations. For the foam block stirrer, a maximum kLSaLS value of 0.6 s−1 was obtained. This shows great potential for further optimization of the liquid flow and therefore the mass transfer. An additional advantage of the foam stirrer reactor is that the solid phase is fixed and the catalyst does not need to be separated downstream from the reactor.
ISSN :	0888-5885
En ligne :	http://www.tue.nl/en/publication/ep/p/d/238146/?no_cache=1

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10751-10757

Titre :	Liquid — solid mass transfer and reaction in a rotor — stator spinning disc reactor
Type de document :	texte imprimé
Auteurs :	Meeuwse, Marco, Auteur ; Sanne Lempers, Auteur ; John Van Der Schaaf, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10751-10757
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Reactor Stator Rotor Mass transfer
Résumé :	The heterogeneously catalyzed oxidation of glucose is performed in a rotor-stator spinning disk reactor. One side of the rotor is coated with a Pt/C and Nafion catalytic layer, resulting in a liquid-solid interfacial area of 274 mi2 mR3. At the lowest rotational disk speed, 26 rad s―1, the reaction is liquid-solid mass transfer limited; at the highest rotational disk speed, 180 rad s―1, the intrinsic kinetics are rate determining. The experimental overall reaction rates are fitted with a resistances in series model, with the activation energy, pre-exponential factor, and volumetric liquid-solid mass transfer coefficient as parameters. The volumetric liquid―solid mass transfer coefficient, kLSαLS, increases from 0.02 to 0.22 mL3 mR―3 s―1 for a rotational disk speed of 26 to 157 rad s '. These values are high in comparison to conventional reactors, like packed beds, in spite of the low liquid-solid interfacial area used in this study. The values of the liquid—solid mass transfer coefficient kLS are 1 order of magnitude higher compared to values reported for packed beds. The Sherwood number for the liquid-solid mass transfer in the rotor―stator spinning disk reactor depends on the Reynolds number to the power 2 in the range I x 105 < Re < 7 x 105. In this range, the transition of laminar flow to turbulent flow takes place, resulting in a change of the mass transfer mechanism.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447968

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10744-10750

Titre :	Gas holdup in gas — liquid stirred tanks
Type de document :	texte imprimé
Auteurs :	Sean G. Mueller, Auteur ; Milorad P. Dudukovic, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10744-10750
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Stirred vessel Hydrodynamics Gas holdup
Résumé :	A single-point optical probe is developed that can accurately obtain local gas holdup in a gas-liquid stirred tank across a wide range of operating pressures, temperatures, and fluids. It is found that the probe orientation to the flow in a stirred tank can cause underestimations in gas holdup if only a single probe orientation is used. The probe is also able to capture the complex flow pattern in the vessel. This allows improved understanding of optical probes and stirred tanks and generation of data at elevated pressure and temperature conditions needed for development of new fundamental models.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447967

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10730-10743

Titre :	Numerical studies of catalyst wetting and total organic carbon reaction on environmentally based trickle - bed reactors
Type de document :	texte imprimé
Auteurs :	Rodrigo J. G. Lopes, Auteur ; Rosa M. Quinta-Ferreira, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10730-10743
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Trickle bed reactor Total organic carbon Wetting Catalyst
Résumé :	This work is devoted to the computational fluid dynamics (CFD) simulation of trickle-bed reactors (TBRs) with environmentally based applications on advanced wastewater remediation technologies. Recently, TBRs have assumed a major role in industrial wastewater treatment plants being envisaged as a breakthrough paraphernalia to move forward superseded decontamination processes. According to the literature, the generous research in environmental reaction engineering has indicated that scale-up of TBRs is erroneous if one considers isothermal operation and uses either a pseudohomogeneous or a heterogeneous model with plug flow for gas and liquid phases. Even though an axial dispersion model may account for liquid distribution nonuniformity, the reaction parameters are strongly dependent on the reactor fluid dynamics. In our case-study, first we developed a volume-of-fluid CFD framework which accounts for the surface tension and wall adhesion effects. A three-dimensional computational domain was employed to investigate and validate the multiphase flow model at diverse operating conditions. The catalytic wet oxidation of high-strength phenolic wastewaters was taken as our case study to evaluate axial profiles of temperature and total organic carbon depletion rates. Second, the theoretical calculations were compared against experimental data taken from a TBR pilot plant. The CFD simulations have shown promising results on how fluid dynamics can be correlated with chemical reaction, namely on the prediction of total organic carbon conversions functionalized by nominal liquid flow rates and attained at different temperatures. Finally, the effect of temperature on the spatial distribution studies of liquid phase gave rise to the requirement of higher liquid throughput to achieve sufficient liquid holdup for the same total organic carbon conversions at elevated temperatures.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447966

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10715-10729

Titre :	Fast reactions in bubbly flows : Film model and micromixing effects
Type de document :	texte imprimé
Auteurs :	Stefan Radl, Auteur ; Daniele Suzzi, Auteur ; Johannes G. Khinast, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10715-10729
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Micromixing Modeling Bubble flow Fast reaction
Résumé :	In our work, we focus on the Euler-Lagrange strategy to simulate bubbly flows and fast chemical reactions. We propose a film model to account for fast, multistep chemical reactions near the gas—liquid interface. A combination of such a film model with Euler—Lagrange simulations for bubbly flows has not been used before. Also, we account for micromixing effects with respect to chemical reactions in the liquid bulk by solving for the variance of the concentration field. To validate our model predictions for multiphase flow and reactive mixing, we compare our results with literature data and find excellent agreement.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447965

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10707-10714

Titre :	Catalytic wet air oxidation of phenolic compounds and mixtures over activated carbon : Conversion, mineralization, and catalyst stability
Type de document :	texte imprimé
Auteurs :	Catherine Ayral, Auteur ; Carine Julcour Lebigue, Auteur ; Frank Stuber, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10707-10714
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Stability Catalyst Mineralization Activated carbon Oxidation Wet air Catalytic reaction
Résumé :	Catalytic wet air oxidation (CWAO) of phenolic compounds over three activated carbons (ACs) has been investigated in a semibatch autoclave to better understand the influence of AC properties on the efficiency and stability of CWAO. Phenol, 4-nitrophenol, 4-chlorophenol, and 4-hydroxybenzoic acid, as well as synthetic mixtures comprising two to four of the aforementioned molecules, have been chosen as model pollutants to evaluate synergy or competition effects. To this end, the amount of pollutant(s) (re)adsorbed on AC during a preliminary adsorption step, the pollutant conversion, and the mineralization yield obtained during CWAO as well as the AC stability upon recycling are compared for each case.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447964

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10698-10706

Titre :	Hydroformylation of 1 - octene using [Bmim] [PF6] — decane biphasic media and rhodium complex catalyst : Thermodynamic properties and kinetic study
Type de document :	texte imprimé
Auteurs :	Amit Sharma, Auteur ; Carine Julcour Lebigue, Auteur ; Raj M. Deshpande, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10698-10706
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Kinetics Thermodynamic properties Catalyst
Résumé :	A chemical reaction engineering approach is reported to investigate the biphasic hydroformylation of 1-octene using [bmim][PF6] ionic liquid. It is based both on a process parameter investigation (temperature, concentrations, and pressures) and a thermodynamic study of the reaction medium (gas-liquid and liquid—liquid equilibria). Initial rate data show complex behavior with respect to operating parameters and are best described by a rate equation based on a mechanistic model. Complete reaction scheme including isomerization is then modeled accounting from the time dependent concentration of the organic substrates measured in organic phase and recalculated in ionic liquid phase from liquid-liquid equilibria.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447963

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10689-10697

Titre :	Gas Fraction and Bubble Dynamics in Structured Slurry Bubble Columns
Type de document :	texte imprimé
Auteurs :	Nasim Hooshyar, Auteur ; Peter J. Hamersma, Auteur ; Robert F. Mudde, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10689-10697
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Particle suspension Bubble column Hydrodynamics
Résumé :	With the aim of structuring the flow and reducing backmixing in slurry bubble columns, we investigate the effect of needle spargers in three-phase systems. We apply optical probes in a 2D and 3D column to measure the bubble dynamics and gas fraction. Experimental results for air-water-glass beads show that an increase in solids volume fraction (1) decreases the gas fraction, (2) shifts the transition point from homogeneous to heterogeneous flow to a lower gas velocity, (3) increases the mean bubble velocity by 60-100% in the range of superficial gas velocities from 0.02 to 0.1 m/s, and (4) has only a limited effect on the bubble size distribution. Fitting our experimental data to the Richardson and Zaki and Garnier models shows that we cannot use the model coefficients they report in their papers. However, fitting our data results in realistic values for the terminal bubble velocity in a swarm. By using needle spargers, giving a very uniform gas supply, a first step toward structuring the hydrodynamics of slurry bubble columns has been taken.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447962

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10682-10688

Titre :	Study of radial heat transfer in a tubular fischer - tropsch synthesis reactor
Type de document :	texte imprimé
Auteurs :	Xiaowei Zhu, Auteur ; Xiaojun Lu, Auteur ; Xinying Liu, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10682-10688
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Reactor Fischer Tropsch synthesis Heat transfer
Résumé :	A series of experiments were performed to investigate and compare the heat transfer characteristics of a catalyst bed during the Fischer-Tropsch synthesis (FTS) reaction and heating without the reaction. A Co/ TiO2 catalyst was used in a relatively large internal diameter (ID) tubular reactor. In the first set of experiments, the bed was run under typical low-temperature FTS conditions, while in the second set an inert gas was fed to the bed and a heater with variable heat output was used along the center axis of the catalytic bed to generate the temperature profile. The two-dimensional (radial and axial) temperature profiles in the bed in both cases were measured for varying flow rates and reactor wall temperatures. Simple radial heat transfer models were derived for these two sets of experiments, and the effective thermal conductivity coefficients of the catalyst bed were estimated. Comparisons of the results showed that there were considerable differences between the values of the coefficients and in the shape of the temperature profiles in the reaction and nonreaction cases. This suggests that the liquid formed during the reaction may play an important role in affecting the heat transfer characteristics of the catalyst bed.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447961

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010)

Titre :	Reactor Scale-up for Fluidized Bed Conversion of Ethane to Vinyl Chloride
Type de document :	texte imprimé
Auteurs :	Daniel A. Hickman, Auteur ; Mark E. Jones, Auteur ; Zoran R. Jovanovic, Auteur
Année de publication :	2011
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Fluidized bed Fluidization Scale effect Extrapolation Reactor
Résumé :	Novel LaOCl/LaCl3 catalysts have been discovered that enable the production of vinyl chloride monomer from ethane. An ethane-based process would result in both capital savings and raw materials savings when compared to the current most effective vinyl technology. These materials are unique in the world of chlorination/ oxychlorination as the mechanism for chlorination over LaOCl/LaCl3 occurs on a catalyst without a redox metal center, unlike the conventional CuCl2 catalysts used for oxychlorination, where the Cu species are reducible. This report focuses on the engineering approaches taken and the challenges encountered in the scale-up of a fluidized bed reactor based on this catalyst technology. The objective is to highlight the application of chemical reaction engineering principles to an industrial reactor scale-up, with special attention to the unexpected and atypical challenges encountered in this development effort.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447960

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10663–10673

Titre :	Multiscale modeling of TiO2 nanoparticle production in flame reactors : Effect of chemical mechanism
Type de document :	texte imprimé
Auteurs :	Maulik Mehta, Auteur ; Yonduck Sung, Auteur ; Venkatramanan Raman, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10663–10673
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Nanoparticle Chemical mechanism
Résumé :	For titanium dioxide (TiO2) nanoparticles manufactured in flame reactors, the precursor is injected into a pre-existing flame, exposing it to a high-temperature gas phase, leading to nucleation and particle growth. Predictive modeling of this chemical process requires simultaneous development of detailed chemical mechanisms describing gas-phase combustion and particle evolution, as well as advanced computational tools for describing the turbulent flow field and its interactions with the chemical processes. Here, a multiscale computational tool for flame-based TiO2 nanoparticle synthesis is developed and a flamelet model representing detailed chemistry for particle nucleation is proposed. The effect of different chemical mechanisms (i.e., one-step, detailed, flamelet) on the prediction of nanoparticle nucleation is investigated using a plug-flow reactor and a partially stirred tank reactor to model the flow field. These simulations demonstrate that particle nucleation occurs much later in the flame with detailed titanium oxidation chemistry, compared to one-step chemistry. Finally, a large-eddy simulation tool is developed to study the effect of precursor injection configuration on nanoparticle formation in turbulent flames.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie100560h

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10651–10662

Titre :	Kinetic modeling of nanoprecipitation using CFD coupled with a population balance
Type de document :	texte imprimé
Auteurs :	Janine Chungyin Cheng, Auteur ; Rodney O. Fox, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10651–10662
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Kinetic Nanoprecipitation
Résumé :	A model study has been conducted for Flash Nanoprecipitation (FNP)—a novel approach to produce functional nanoparticles. A population balance equation with the FNP kinetics has been integrated into a computational fluid dynamics (CFD) simulation of a custom-designed microscale multi-inlet vortex reactor (MIVR) to yield conditions comparable to the real experimental settings. In coping with the complicated aggregation model in the CFD code, a new numerical approach, the conditional quadrature method of moments (CQMOM), has been proposed, which is capable of solving the multivariate system efficiently and accurately. It is shown that the FNP process is highly influenced by mixing effects in the microreactor, and thus coupling CFD with the kinetics model is essential in obtaining valid comparisons with experiments.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie100558n

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10641-10650

Titre :	Catalyst deactivation in 3D CFD resolved particle simulations of propane dehydrogenation
Type de document :	texte imprimé
Auteurs :	Mohsen Behnam, Auteur ; Anthony G. Dixon, Auteur ; Michiel Nijemeisland, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10641-10650
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Dehydrogenation Computational fluid dynamics Deactivation Catalyst
Résumé :	Catalyst deactivation by carbon deposition has been investigated for the dehydrogenation of propane to propene on a Cr2O3/Al2O3 catalyst. Computational fluid dynamics was used to couple the 3D transport and reaction processes occurring inside the cylindrical pellet to the gas flow around the pellet. The pellet scale reaction and carbon laydown are shown to be strongly affected by the bed scale tube wall heat flux supplied for the endothermic reactions, and the species distributions on the pellet surface are also affected by the case of reactant access to the particle. The development of particle internal gradients and carbon accumulation are illustrated for the early stages of deactivation. Carbon deposition is initially strongest in the high temperature regions close to the tube wall. As time progresses, the increased deactivation caused by the carbon acts to reduce all rates of reaction, and propene production and coke formation shift to other regions of the pellet.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447957

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010)

Titre :	Potential of Microchannel Flow for Agglomerate Breakage
Type de document :	texte imprimé
Auteurs :	J. J. Derksen, Auteur ; Dmitry Eskin, Auteur
Année de publication :	2011
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Microchannel flow
Résumé :	Direct simulations of laminar solid−liquid flow in microchannels with full resolution of the solid−liquid interfaces have been performed. The solids phase consists of simple agglomerates, assembled of monosized, spherical particles. The flow of the interstitial liquid is solved with the lattice-Boltzmann method. Solids and fluid dynamics are two-way coupled. The simulations keep track of the flow-induced forces in the agglomerates. The effects of agglomerate type (doublets, triplets, and quadruplets), solids loading, and channel geometry on (the statistics of the) flow and collision-induced forces has been investigated. By comparing these forces with agglomerate strength, we would be able to assess the potential of microchannels as agglomerate breakage devices.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie100442e

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10627-10632

Titre :	Hydrogen peroxide direct synthesis : Selectivity enhancement in a trickle bed reactor
Type de document :	texte imprimé
Auteurs :	Pierdomenico Biasi, Auteur ; Federica Menegazzo, Auteur ; Francesco Pinna, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10627-10632
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Trickle bed reactor Hydrogen peroxide
Résumé :	H2O2 direct synthesis over a palladium catalyst based on sulfated ceria (Pd-CeS) has been studied in a trickle-bed reactor at ― 10 °C. The combined effect of liquid and gas flow rates was studied by independent variations. The maximum productivity and selectivity was always found at flow rate combinations intermediate within the investigated range. The reactor operated under pressure and its effect was investigated (10 and 20 bar), resulting in a significant gain in selectivity. Selectivity up to 80% has been measured at the highest pressure tested (20 bars), liquid flow rate of 2 mL/min, and 6 mL/min gas flow rate. The maximum production rate measured was 0.0035 mmol/min with 0.5 mL/min liquid flow rate and 2.7 mL/min gas flow rate. Relevance of direct water formation has been isolated by independently investigating H2O2 decomposition and hydrogenation. Results indicate directions of further performance improvements and the importance of reactor type and operation.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447955

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10615-10626

Titre :	Experimental investigations of rise behavior of monodispersed / polydispersed bubbly flows in quiescent liquids
Type de document :	texte imprimé
Auteurs :	Swapna S. Rabha, Auteur ; Vivek V. Buwa, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10615-10626
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Bubble flow
Résumé :	The predictive capabilities of continuum CFD models to simulate large-scale dispersed gas—liquid flows depend on the closures used to estimate the interphase coupling forces. The present manuscript shows that different corrections that are applied to correct the drag force for multiple bubble systems lead to different predictions as the gas volume fraction is increased. In the present work, experimental investigations of monodispersed and polydispersed bubbles of different diameters (1.2 ≤ dB ≤ 7.5 mm) rising in quiescent water (0.19 ≤ Eo ≤ 8.72; log Mo = -10.5) at different gas volume fractions (0.01 < αG < 0.2) are reported. The bubble rise velocity of a single isolated bubble, a bubble rising in a single chain and bubbles rising in multiple chains were compared. The effect of bubble diameter and gas volume fraction on the fluctuations in bubble rise velocities of individual bubbles rising in multiple chains was also investigated. The rise velocities of monodispersed bubble swarms were found to increase with the increase in dB and αG. The number- and time-averaged bubble rise velocity and drag coefficient for monodispersed bubble swarms were investigated as a function of αG. The drag coefficients based on the slip velocity of the bubble swarms for αG < 0.1 were found to decrease with increase in αG and showed good agreement with the previous literature; but for αG > 0.1, the drag coefficient were found to be independent of αG. Further, the rise behavior of poly dispersed bubbles was also investigated.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447954

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10606-10614

Titre :	Numerical simulations of liquid — liquid flows in microchannels
Type de document :	texte imprimé
Auteurs :	Richa Raj, Auteur ; Nikita Mathur, Auteur ; Vivek V. Buwa, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10606-10614
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Liquid liquid flow Numerical simulation
Résumé :	Liquid-liquid flows in microchannels are important to microreactors/microfluidic devices that are used to carry out liquid-liquid reactions, extractions, emulsifications, etc. In this work, we report numerical investigations of drop/slug formation and flow regimes for liquid-liquid (oil-water) flow in microchannels. The Volume of Fluid (VOF) method was used to simulate the dynamics of water drop/slug formation in silicon oil, and the predicted drop/slug shapes/lengths were compared with previous literature measurements [Garstecki et al., Lab Chip 2006, 6, 437-446]. The effects of flow rates of water and oil phases (0.019―0.417 and 0.004―0.14 μL/s, respectively), channel size, liquid-liquid distributor (T-junction and Y-junction), and liquid viscosity on liquid-liquid flow regimes and slug lengths were investigated. The predicted drop/slug formation dynamics/slug lengths agreed satisfactorily with the aforementioned Garstecki et al. literature measurements for Qwater/Qoil in the range of 0.1-1.7. However, for Qwater/Qoil > 1.7, unlike the (long) slug flow reported in the aforementioned Garstecki et al. literature, a parallel flow was observed in the numerical simulations. The effect of wall adhesion (contact angle) on the flow regimes and slug lengths was also investigated. The experimentally validated computational model will be useful to simulate mixing, transport processes, and chemical reactions in microchannels.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447953

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10588-10605

Titre :	Estimation of numerical errors related to some basic assumptions in discrete particle methods
Type de document :	texte imprimé
Auteurs :	Sofiane Benyahia, Auteur ; Janine E. Galvin, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10588-10605
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Estimation Discrete particle methods
Résumé :	Discrete particle methods that track the motion of individual particles and their collisions are computationally very expensive. To accelerate these numerical simulations, some basic assumptions have been introduced and reported in the literature. This study investigates two of these common assumptions: (1) the use of computational parcels, or clouds, wherein many particles are lumped together so that only parcels and their collisions are tracked, and (2) the multiphase particle-in-cell, or MP-PIC, wherein the collision forces are replaced by a solids pressure term with the main purpose to avoid exceeding the maximum packing of the granular assembly. Using several cases relevant to the fluidization community, errors associated with these assumptions are computed. For these cases the magnitude of error in the time-averaged flow variables indicates that further research on the validity of these assumptions is warranted.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447952

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10581-10587

Titre :	Stationary thermal stability analysis of a gas oil hydrotreating reactor
Type de document :	texte imprimé
Auteurs :	Sardella Palmar, Auteur ; J. M. Schweitzer, Auteur ; H. Wu, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10581-10587
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Reactor Hydrotreating Gas oil Thermal stability
Résumé :	Thermal stability analysis is imperative to ensure the safe operation of chemical reactors carrying out highly exothermic reactions. We present a thermal stability study for a fixed bed gas oil hydrotreating reactor working at industrial operating conditions, which involves three phases, 15 lumped hydrocarbon chemical families (saturates, olefins, sulfur containing compounds, triaromatics, diaromatics, and monoaromatics), and distributed in 3 boiling point cuts to differentiate light and heavy hydrocarbons. The influence of various system parameters on the reactor thermal stability has been investigated using the sensitivity-based Morbidelli-Varma criterion. It is found that most of the operating parameters can be used in principle to tune the reactor thermal stability, except for the inlet feed temperature, which, though shifting the occurrence of runaway to different parameter regimes, does not improve the reactor thermal stability behavior. In addition, the convective heat removal plays an important role in changing the reactor thermal stability. The obtained results are given in various operating parameter planes, which arc divided by the criticality curves for parametric sensitivity into three regimes, LTO (low-temperature operation), HTO (high-temperature operation), and M (multiplicity), thus forming various reactor operation diagrams, which can be used to guide the reactor design and operation.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447951

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10572-10580

Titre :	Hydrolysis of isobutyric anhydride : Effect of partial miscibility of reactants on kinetics
Type de document :	texte imprimé
Auteurs :	R. C. Ramaswamy, Auteur ; Mills Bailey, Auteur ; Scott Barnicki, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10572-10580
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Kinetics Hydrolysis
Résumé :	Hydrolysis of isobutyric anhydride suffers from the mass transfer issues associated with the inherent partial miscibility of the participating reactants in a certain concentration—temperature space. Hence, activity-based models are developed and used to describe the phase equilibrium behavior and the kinetics. In this work, the experimental and modeling approaches employed to study the kinetics in the single- and two-phase regions are presented. The solvation effects or the effect of autocatalysis on the rate of hydrolysis are studied. A discussion on the use of external acid catalysts/autocatalysis to enhance the rate of this reaction, especially in the two-phase region, and its application as a potential hazard identification tool is also presented.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447950

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10565-10571

Titre :	Application of an Existing Detailed Chemical Kinetic Model to a Practical System of Hot Coke Oven Gas Reforming by Noncatalytic Partial Oxidation
Type de document :	texte imprimé
Auteurs :	Koyo Norinaga, Auteur ; Hiroshi Yatabe, Auteur ; Masahiro Matsuoka, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10565-10571
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Modeling Partial oxidation Reforming Coke oven gas Kinetic model
Résumé :	For more efficient utilization of coke oven gas (COG), a byproduct from the production of metallurgical cokes, a reforming technology of hot COG (HCOG) was developed to obtain material gases suitable for methanol production. A test plant was installed on a platform of an operating coke oven. HCOG was fed into a tubular reactor (0.6 m i.d. and 3.2 m long) at flow rates from 28 to 103 Nm3/h and was partially oxidized by injecting O2 (from 12 to 30 Nm3/h) from nozzles near the inlet. Exhaustive test runs identified the appropriate reforming conditions required to achieve more than 2.2-fold syngas amplifications, and the optimum product gas composition for methanol synthesis. Numerical simulations using detailed chemical kinetics coupled with a plug-flow reactor model were also conducted. The kinetic model developed by Richter and Howard [Phys. Chem. Chem. Phys. 2002, 4, 2038―2055] including 257 chemical species and 2216 elementary steplike reactions was used. HCOG was modeled as a multicomponent gas mixture involving H2, CO, CO2, CH4, C2 hydrocarbons, H2O, and 31 aromatic hydrocarbons such as benzene and toluene, as well as polycyclic aromatic hydrocarbons up to coronene, to represent the HCOG tar. Satisfactory agreement was observed in comparisons between the predictions from the numerical simulations and the data measured from the 20 test runs, indicating that the model can be a promising tool toward designing a demonstration/commercial HCOG reforming plant.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447949

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10558-10564

Titre :	Prediction of 3D transversal patterns in packed - bed reactors using a reduced 2D model : Oscillatory kinetics
Type de document :	texte imprimé
Auteurs :	Olga Nekhamkina, Auteur ; Moshe Sheintuch, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10558-10564
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Kinetics Two dimensional model Fixed bed reactor Prediction
Résumé :	We have recently showed the formation of transversal patterns in a 3D cylindrical reactor in which an exothermic first-order reaction of Arrhenius kinetics occurs with variable catalytic activity. Under these oscillatory kinetics, the system exhibits a planar front (1D) solution, with the front position oscillating in the axial direction, while in the 3D case, three types of transversal patterns can emerge: rotating fronts, oscillating fronts with superimposed transversal (nonrotating) oscillations, and mixed rotating-oscillating fronts. In the present study, we analyze the possible reduction of the 3D model to a 2D cylindrical shell model to predict patterns. We map bifurcation diagrams showing domains of different modes using the reactor radius (R) as a bifurcation parameter and show that the front divergence and the domains of the kn-mode pattern in the 3D model [corresponding to the transversal eigenfunction Jk(μknr) exp(ikθ), in which Jk is the Bessel function of the first kind] can be predicted by those of the one wave in the 2D model using the linear transformation R3D = μknR2D.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447948

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10549-10557

Titre :	A Revised method of attainable region construction utilizing rotated bounding hyperplanes
Type de document :	texte imprimé
Auteurs :	David Ming, Auteur ; Diane Hildebrandt, Auteur ; David Glasser, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10549-10557
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Hyperplane
Résumé :	An improved method of candidate attainable region (AR) construction, based on an existing bounding hyperplanes approach, is presented. The method uses a plane rotation about existing extreme points, rather than a plane translation, to eliminate unachievable regions from an initial bounding set. The algorithm is shown to be faster, but has currently only been implemented for two-dimensional constructions and has been extended to include the construction of candidate ARs that involve nonisothermal kinetics in concentration and concentration-time space.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447947

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10535-10548

Titre :	Methodology for the design of optimal chemical reactors based on the concept of elementary process functions
Type de document :	texte imprimé
Auteurs :	Andreas Peschel, Auteur ; Hannsjorg Freund, Auteur ; Kai Sundmacher, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10535-10548
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Chemical reactor Optimal design
Résumé :	In this contribution, a methodology for the optimal design of chemical reactors based on the best reaction route in the thermodynamic state space is proposed. This route is obtained by tracking a fluid element on its way through the reactor and manipulating the fluxes into this element. Instead of choosing the reactor design a priori and optimizing the free parameters of the chosen reactor setup, an innovative reactor design is developed based on the optimal flux profiles. Besides classical reactor concepts, this methodology is suited to investigate the potential of different process intensification options such as integration of reaction, cooling and separation in a single apparatus, or the application of high interface areas for heat and mass transfer. The methodology is exemplarily illustrated for the development of a new SO2 oxidation reactor. The residence time as an example for a meaningful objective is minimized, and a reduction of 69% compared to the optimized technical reference case is achieved.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447946

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10524-10534

Titre :	Evaluation of photon absorption in an aqueous Ti02 slurry reactor using monte carlo simulations and macroscopic balance
Type de document :	texte imprimé
Auteurs :	Jesus Moreira, Auteur ; Benito Serrano, Auteur ; Aaron Ortiz, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10524-10534
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Monte Carlo method Particle suspension Reactor Photon absorption
Résumé :	The radiation field in an annular photocatalytic reactor is simulated using a Monte Carlo method (MC) for two TiO2 suspensions in water. Simulations are performed by using both the spectral distribution and the wavelength-averaged scattering and absorption coefficients. The Henyey-Greenstein phase function is adopted to represent forward, isotropic, and backward scattering modes. It is assumed that the UV lamp reflects the backscattered photons by the slurred medium. Photoabsorption rates using MC simulations and spectral distribution of the optical coefficients agree closely with experimental observations from a macroscopic balance. It is found that the scattering mode of the probability density function is not a critical factor for a consistent representation of the radiation field. MC simulation for the optimal catalyst concentration reveals that the maximum LVREA is reached at a concentration of 0.14 g L―1 for TiO2 Degussa P25. From this concentration, the apparent optical thickness is determined to be 2.8476 which is in agreement with the optimal one previously reported. This concentration is comparable to that determined experimentally for phenol photocatalytic degradation.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447945

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10517-10523

Titre :	Dynamic simulation of mixing - limited symmetric and asymmetric patterns in homogeneous autocatalytic reactors
Type de document :	texte imprimé
Auteurs :	Anwesha Chaudhury, Auteur ; Chakraborty Saikat, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10517-10523
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Modeling Reactor Autocatalysis Mixing Dynamic model
Résumé :	In this paper, we study the dynamic evolution of mixing-limited patterns in homogeneous autocatalytic reactors. Using a regularized low-dimensional model derived through the spatial averaging of the 3-D convection-diffusion-reaction equation using Liapunov-Schmidt technique of the classical bifurcation theory, we simulate the process of formation of asymmetric patterns that develop from differences in mixing and reaction time scales, and are widely observed in experimental studies. We also perform a detailed parametric analysis in order to quantify the effects of the parameters Pe, p, and Da on the formation, evolution and stability of patterns. Our nonlinear dynamic simulations show that increased transverse mixing limitations in the reactor help excite a broad spectrum of eigen modes that produce patterns of various length scales and axes of symmetry. These patterns coexist and superimpose to generate asymmetric patterns that are more stable than the symmetric ones formed from lower eigen modes.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447944

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10510-10516

Titre :	Multivariable Model Predictive Control of Thin Film Surface Roughness and Slope for Light Trapping Optimization
Type de document :	texte imprimé
Auteurs :	Xinyu Zhang, Auteur ; Gangshi Hu, Auteur ; Gerassimos Orkoulas, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10510-10516
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Optimization Trapping Roughness Thin film Predictive control Modeling
Résumé :	This work focuses on the development of a multivariable model predictive controller that simultaneously regulates thin film surface roughness and mean slope to optimize light reflectance and transmittance during thin film manufacturing by manipulating substrate temperature and deposition rate. Surface roughness and surface slope are defined as the root-mean-squares of the surface height profile and the surface slope profile, respectively. The dynamics of the evolution of the thin film surface height profile are assumed to be described by an Edwards-Wilkinson-type equation (a second-order stochastic partial differential equation) in two spatial dimensions. Analytical solutions of the expected surface roughness and surface slope are obtained on the basis of the Edwards-Wilkinson equation and are used in the controller design. The model parameters of the Edwards-Wilkinson equation depend on the substrate temperature and deposition rate. This dependence is used in the formulation of the predictive controller to predict the influence of the control action on the surface roughness and slope at the end of the growth process. The model predictive controller involves constraints on the magnitude and rate of change of the control action and optimizes a cost that involves penalty on both surface roughness and mean slope from the set-point values. The controller is applied to the two-dimensional Edwards-Wilkinson equation and is shown to successfully regulate surface roughness and mean slope to set-point values at the end of the deposition that yield desired film reflectance and transmittance.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447943

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10496–10509

Titre :	Output feedback control of distributed parameter systems using adaptive proper orthogonal decomposition
Type de document :	texte imprimé
Auteurs :	Sivakumar Pitchaiah, Auteur ; Antonios Armaou, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10496–10509
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Feedback Orthogonal decomposition
Résumé :	We address the problem of tracking and stabilization of dissipative distributed parameter systems, by designing static output feedback controllers using adaptive proper orthogonal decomposition methodology (APOD). Initially, an ensemble of eigenfunctions is constructed based on a relatively small data ensemble which is then recursively updated as additional process data becomes available periodically. The proposed APOD methodology relaxes the need for a representative ensemble of snapshots (in the sense that it contains the global dynamics of the process). An accurate reduced-order model (ROM) is constructed and periodically refined based on these updated eigenfunctions. Using the ROM and continuous measurements available from the restricted number of sensors, a static output feedback controller is subsequently designed. This controller is successfully used to achieve the desired control objective of stabilization and tracking in the Kuramoto−Sivashinksy and FitzHugh−Nagumo equations.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie100463f

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10486–10495

Titre :	Catalytic cacking of methylcyclohexane on FAU , MFI , and bimodal porous materials : Influence of acid properties and pore topology
Type de document :	texte imprimé
Auteurs :	Rhona Van Borm, Auteur ; Marie-Françoise Reyniers, Auteur ; Johan A. Marten, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10486–10495
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Résumé :	Catalytic cracking of methylcyclohexane has been studied on eight commercially available zeolites, five FAUs and three MFIs, and on two newly developed zeotype materials with bimodal porous structure, BIPOMs. Both BIPOMs are composed of an MFI ultramicropore (<1 nm) network and a different supermicropore (1.5−2.0 nm) network. Site time yields obtained on FAU and MFI zeolites with varying acid properties are in the same range, showing that mass transfer limitations inside the pores of both zeolite frameworks are absent. Site time yields obtained on BIPOM3 are comparable to those on commercial MFI with similar Si/Al ratio, while BIPOM1 is significantly less active. Within a given framework type, the zeolite acid properties determine its activity in methylcyclohexane cracking, while the pore topology controls its selectivity. On FAU, methylcyclohexane isomerization, followed by ring opening and subsequent cracking, is the main reaction pathway, while on MFI, protolytic scission, followed by cracking, is predominant. This is explained by the occurrence of transition state shape selectivity in MFI, hampering the bimolecular hydride transfer reaction. These typical features allow one to distinguish between FAU- and MFI-type catalytic behavior and to locate the active sites of BIPOM1 mainly in the supermicropores and those of BIPOM3 in both micropore networks but to a greater extent in the ultramicropores.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie100429u

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10479–10485

Titre :	The direct epoxidation of propene in the explosive regime in a microreactor — a study into the reaction kinetics
Type de document :	texte imprimé
Auteurs :	T. Alexander Nijhuis, Auteur ; Jiaqi Chen, Auteur ; Stefanie M. A. Kriescher, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10479–10485
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Microreactor Kinetics
Résumé :	The usage of a microreactor system for the direct epoxidation of propene over a gold-titania-based catalyst system using a mixture of hydrogen, oxygen, and propene allows for the safe operation of the reaction in the explosive regime. A kinetic study was performed on the effect of the concentration of hydrogen, oxygen, and propene on the reaction rate as well as the catalyst deactivation and reactivation. A simple algebraic expression was developed, based on published kinetics, which provided the three reaction rate constants as a function of the feed gas concentrations. It is shown that the propene concentration does not influence the propene oxide formation rate; however, higher propene concentrations significantly reduce the catalyst deactivation rate. Hydrogen increases the rate of the epoxidation reaction, while it only has a minor influence on the rate of deactivation and reactivation. Oxygen has a beneficial effect on the epoxidation reaction: it slightly decreases the deactivation rate and is beneficial for the catalyst reactivation. It is shown that, for the gold on titania dispersed on a silica catalyst used in this study, it is advantageous to perform the direct propene epoxidation in a microreactor system at the highest possible feed concentrations for each of the reactants. This results in the highest propene oxide productivity and the lowest deactivation rate.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie1004306

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10471–10478

Titre :	Incorporation of detailed chemical mechanisms in reactive flow simulations using element - flux analysis
Type de document :	texte imprimé
Auteurs :	Kaiyuan He, Auteur ; Ioannis P. Androulakis, Auteur ; Ierapetritou, Marianthi G., Auteur
Année de publication :	2011
Article en page(s) :	pp. 10471–10478
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Fluid dynamics
Résumé :	An on-the-fly mechanism reduction approach for coupling complex chemistry and computational fluid dynamics (CFD) is proposed in this paper. The approach consists of element flux analysis and identification of active species and reactions based on flux magnitudes. A reduced mechanism involving the active species and reactions is generated to describe the local chemistry. The approach is applied dynamically in the CFD calculation by generating a locally accurate reduced mechanism for every computational cell and time step, enabling on-the-fly reduction. The emphasis of this work is on the numerical study of stratified homogeneous charge compression ignition (HCCI) combustion with detailed chemistry by using the proposed on-the-fly reduction scheme. A mechanism of n-heptane combustion with 161 species and 1540 reactions is used as the detailed mechanism in the simulation. KIVA-3V and CHEMKIN are used as the computational platforms. On-the-fly reduction predictions of species concentrations, temperature, and pressure are in excellent agreement with solutions obtained with the detailed mechanism but at a tremendously reduced CPU time. The on-the-fly reduction approach enables detailed characterizations of in-cylinder behaviors in stratified HCCI engines by incorporating detailed chemical kinetics in engine CFD computations.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie100490w

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10459–10470

Titre :	Rule-Based Generation of Thermochemical Routes to Biomass Conversion
Type de document :	texte imprimé
Auteurs :	Srinivas Rangarajan, Auteur ; Aditya Bhan, Auteur ; Prodromos Daoutidis, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10459–10470
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Thermochemical Biomass
Résumé :	Biomass conversion to fuels and chemicals involves a multitude of oxygen-containing compounds and thermochemical reaction routes. A detailed elucidation of the process chemistry is, thus, a key step in understanding the reaction mechanisms and designing chemical processes in a biorefinery. In this paper, a computational tool, called Rule Input Network Generator (RING), is presented as a platform for modeling diverse homogeneous and heterogeneous chemistries in biomass conversion and automatically generating the underlying complex reaction networks. RING accepts a set of reaction rules and initial reactants as inputs and exhaustively generates the reactions of the system. The reaction center of an elementary step is represented by a SMARTS-like string and identified as a submolecular pattern in a reactant molecular graph using a pattern-matching algorithm. The reaction events are subsequently modeled as a graph transformation system. The generality of this framework was substantiated by the successful application of RING in reproducing the reaction mechanisms of different biomass conversion systems, such as acid-catalyzed dehydration of fructose, base-catalyzed esterification of triglycerides, and gas phase pyrolysis of fatty esters.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie100546t

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10450-10458

Titre :	Oxidative CO2 Reforming of Methane on Alumina-Supported Co−Ni Catalyst
Type de document :	texte imprimé
Auteurs :	Say Yei Foo, Auteur ; Chin Kui Cheng, Auteur ; Tuan-Huy Nguyen, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10450-10458
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Catalyst Reforming Carbon dioxide Oxidation
Résumé :	CO2 reforming of CH4 in the presence of O2 in the feed has been investigated in a fixed bed reactor containing a Co-Ni catalyst. The reforming rate increased with O2 partial pressure before leveling out at O2:CH4 = 1I at temperature greater than 823 K. Although CO production decreased with O2 addition, H2 formation initially rose to a maximum before a slow decline. An expression relating the optimum O2 partial pressure for H2 production as a function of temperature was obtained as, PO2,max = 1.008 × 10―3e8420/T. The H2:CO product ratio increased from 0.9 for pure CO2 reforming and peaked at 1.73 as O2 partial pressure increased to an equimolar level in the feed. The increased reaction temperature resulted in lower H2:CO due to increased CO2 reforming kinetics. The complete consumption of O2 in the final product stream means that the oxidative CO2 reforming of CH4 may be used to generate nearly ideal syngas composition for Fischer-Tropsch synthesis if feed CO2:CH4 is unity. In particular, the overall heat demand for the reforming reaction could be reduced (or become exothermic) for a judicious combination of CO2/CH4/O2. The postreaction analysis revealed that even mild O2 dosing leads to negligible carbon deposition. Thus, this form of reactor operation is energetically attractive and provided efficient carbon utilization.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447937

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10442–10449

Titre :	Lattice Monte Carlo Simulation of Cluster Coalescence Kinetics with Application to Template-Assisted Synthesis of Quantum Dots
Type de document :	texte imprimé
Auteurs :	Sreekumar R. Kuriyedath, Auteur ; Borislava Kostova, Auteur ; Ioannis G. Kevrekidis, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10442–10449
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Kinetics Monte carlo simulation
Résumé :	A Lattice Monte Carlo (LMC) simulation technique has been developed to describe the synthesis of a single semiconductor nanocrystal inside the droplets of a microemulsion. The LMC simulation can track the diffusion of a precursor, its irreversible reaction with a second precursor to form nuclei, and the diffusion and coalescence of the nuclei into clusters and eventually into a single particle. In this paper we compare two scenarios for forming a single nanocrystal. The first scenario involves very rapid (spontaneous) conversion of a precursor dispersed in the droplet to nuclei that diffuse and coalesce into a single particle. The second scenario involves diffusion of a precursor to the droplet interface where an irreversible reaction with a second precursor forms nuclei that subsequently diffuse into the droplet and coalesce. Simulations were performed describing the synthesis of ZnSe nanocrystals with diameters up to 7 nm, i.e., below the quantum confinement threshold of 9 nm for this material. Comparison of the time required for the formation of a single final particle in each of the two cases reveals that for particles smaller than 3.5 nm the formation times are nearly equal. For particles larger than 3.5 nm, the second process is completed faster than the first one. Analysis of intermediate cluster populations indicates that the formation of a larger “sweeper” cluster accelerates the rate of coalescence and is more effective when the nuclei are supplied gradually, as in the second process, compared to spontaneous nucleation throughout the domain. The kinetics of coalescence of an initially monodisperse population of nuclei in spherical domains of finite size were studied and generalized equations were obtained that describe the evolution of the number of different sizes as function of dimensionless time; this constitutes an extension to the classical analysis of coalescence of monodisperse aerosols in an infinite domain.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie101109p

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10428-10437

Titre :	Development of a strong acid ion exchange resin with a monolithic microhoneycomb structure using the Ice templating method
Type de document :	texte imprimé
Auteurs :	Shin R. Mukai, Auteur ; Yoshitaka Satoh, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10428-10437
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Storage Sputtering Catalyst Adsorption
Résumé :	Temporal Analysis of Products (TAP) reactor system was used to investigate CO oxidation behavior on Au/SiO2 catalysts prepared via the physical vapor deposition method of magnetron sputtering. Au/SiO2 catalysts are a valuable model system for studying the reactivity of Au nanoparticles, as the SiO2 support plays little role in the reaction. The adsorption of CO on the catalyst was studied at different temperatures under TAP vacuum conditions. The heat of CO adsorption estimated from TAP results by moment analysis is ―24.39 ± 3.70 kJ/mol. Multipulse TAP experiments showed the important dependency between the oxygen pretreatment pressure (UHV to 33.66 psia) and catalytic activity for CO oxidation. The observed kinetic behavior indicates that oxygen consumed by CO can be replenished by oxygen stored in a reservoir, which is filled during pretreatment. The oxygen pretreatment pressure determines the amount of oxygen stored in the reservoir. The kinetic behavior indicates that oxygen is stored in the gold subsurface or at the Au/SiO2 interface, and that the active oxygen species is atomically adsorbed oxygen.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447934

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10428-10437

Titre :	Oxygen and CO adsorption on Au / SiO2 catalysts prepared by magnetron sputtering : The role of oxygen storage
Type de document :	texte imprimé
Auteurs :	Xiaolin Zheng, Auteur ; Gabriel M. Veith, Auteur ; Evgeniy Redekop, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10428-10437
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Storage Sputtering Catalyst Adsorption
Résumé :	Temporal Analysis of Products (TAP) reactor system was used to investigate CO oxidation behavior on Au/SiO2 catalysts prepared via the physical vapor deposition method of magnetron sputtering. Au/SiO2 catalysts are a valuable model system for studying the reactivity of Au nanoparticles, as the SiO2 support plays little role in the reaction. The adsorption of CO on the catalyst was studied at different temperatures under TAP vacuum conditions. The heat of CO adsorption estimated from TAP results by moment analysis is ―24.39 ± 3.70 kJ/mol. Multipulse TAP experiments showed the important dependency between the oxygen pretreatment pressure (UHV to 33.66 psia) and catalytic activity for CO oxidation. The observed kinetic behavior indicates that oxygen consumed by CO can be replenished by oxygen stored in a reservoir, which is filled during pretreatment. The oxygen pretreatment pressure determines the amount of oxygen stored in the reservoir. The kinetic behavior indicates that oxygen is stored in the gold subsurface or at the Au/SiO2 interface, and that the active oxygen species is atomically adsorbed oxygen.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447934

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10421–10427

Titre :	Synthesis of pyrolytic carbon composites using ethanol as precursorm
Type de document :	texte imprimé
Auteurs :	Aijun Li, Auteur ; Shouyang Zhang, Auteur ; Boris Reznik, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10421–10427
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Pyrolytic Ethanol
Résumé :	Chemical vapor infiltration and deposition of carbon fiber bundles are applied to synthesize pyrolytic carbon composites using the oxygen-containing precursor ethanol. The influence of the temperature (1373 and 1423 K) and pressure (1−7 Pa) on the microstructure and the deposition rate of pyrolytic carbon are experimentally studied. Higher partial pressures of ethanol are demonstrated to favor the growth of highly ordered graphene-like pyrocarbon, whereas lower partial pressures help to suppress the carbon texture transition. The gas-phase composition and reaction kinetics are numerically analyzed on the basis of a reacting flow model with a detailed reaction mechanism. Methane and C2 species are shown to be the dominant intermediate species of ethanol pyrolysis. According to the simulation, a large amount of CH3 radicals is produced, which explains the fact that the pyrolytic carbon from ethanol exhibits a texture similar to the one produced with CH4 as precursor.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie100230b

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10399-10420

Titre :	Accurate high - temperature reaction networks for alternative fuels : Butanol isomers
Type de document :	texte imprimé
Auteurs :	Kevin M Van Geem, Auteur ; Steven P. Pyl, Auteur ; Guy B. Marin, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10399-10420
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	High temperature Isomers
Résumé :	Oxygenated hydrocarbons, particularly alcohol compounds, are being studied extensively as alternatives and additives to conventional fuels due to their propensity of decreasing soot formation and improving the octane number of gasoline. However, oxygenated fuels also increase the production of toxic byproducts, such as formaldehyde. To gain a better understanding of the oxygenated functional group's influence on combustion properties-e.g., ignition delay at temperatures above the negative temperature coefficient regime, and the rate of benzene production, which is the common precursor to soot formation-a detailed pressure-dependent reaction network for n-butanol, sec-butanol, and tert-butanol consisting of 281 species and 3608 reactions is presented. The reaction network is validated against shock tube ignition delays and doped methane flame concentration profiles reported previously in the literature, in addition to newly acquired pyrolysis data. Good agreement between simulated and experimental data is achieved in all cases. Flux and sensitivity analyses for each set of experiments have been performed, and high-pressure-limit reaction rate coefficients for important pathways, e.g., the dehydration reactions of the butanol isomers, have been computed using statistical mechanics and quantum chemistry. The different alcohol decomposition pathways, i.e., the pathways from primary, secondary, and tertiary alcohols, are discussed. Furthermore, comparisons between ethanol and n-butanol, two primary alcohols, are presented, as they relate to ignition delay.
ISSN :	0888-5885
En ligne :	http://www.mendeley.com/research/accurate-hightemperature-reaction-networks-alte [...]

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10392-10398

Titre :	Fundamental study of the oxidation characteristics and pollutant emissions of model biodiesel fuels
Type de document :	texte imprimé
Auteurs :	Feng Qiyao, Auteur ; Yang L. Wang, Auteur ; Fokion N. Egolfopoulos, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10392-10398
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Fuel Modeling Pollutant Oxidation
Résumé :	In this study, the oxidation characteristics of biodiesel fuels are investigated with the goal of contributing toward the fundamental understanding of their combustion characteristics and evaluating the effect of using these alternative fuels on engine performance as well as on the environment. The focus of the study is on pure fatty acid methyl-esters (FAME,) that can serve as surrogate compounds for real biodiesels. The experiments are conducted in the stagnation-flow configuration, which allows for the systematic evaluation of fundamental combustion and emission characteristics. In this paper, the focus is primarily on the pollutant emission characteristics of two C4 FAMEs, namely, methyl-butanoate and methyl-crotonate, whose behavior is compared with that of n-butane and n-pentane. To provide insight into the mechanisms of pollutant formation for these fuels, the experimental data are compared with computed results using a model with consistent C1―C4 oxidation and NO, formation kinetics.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447931

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10386-10391

Titre :	New "enhanced NH3 - SCR" reaction for NOx emission control
Type de document :	texte imprimé
Auteurs :	Pio Forzzatti, Auteur ; Isabella Nova, Auteur ; Enrico Tronconi, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10386-10391
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Pollution abatement Selective catalytic reduction
Résumé :	NH3-selective catalytic reduction (SCR) is applied worldwide to DeNOx of combustion exhausts of stationary and mobile sources, but a greater DeNOx activity at low temperatures is desired to meet forthcoming restrictive legislations and to increase energy efficiency in specific applications. We have obtained high NO reduction efficiencies at 200-300 °C over commercial V-based and Fe-exchanged zeolite catalysts by reacting NO with both ammonia and nitrates (e.g., ammonium nitrate) according to a novel "enhanced SCR" reaction, 2NH3 + 2NO + NH4NO3 → 3N2 + 5H2O. This provides a new route for low-temperature NOx reduction wherein the DeNOx activity is maximized by dosing an aqueous solution of nitrates to the SCR reactor feed stream.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447930

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp.10364-10373

Titre :	First - principles - based kinetic monte carlo simulation of nitric oxide reduction over platinum nanoparticles under lean - burn conditions
Type de document :	texte imprimé
Auteurs :	Donghai Mei, Auteur ; Jincheng Du, Auteur ; Matthew Neurock, Auteur
Année de publication :	2011
Article en page(s) :	pp.10364-10373
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Kinetic Oxide Nanoparticles
Résumé :	This article discusses first-principles-based kinetic Monte Carlo simulation of Nitric Oxide reduction. The kinetics for NO reduction over supported platinum under lean condition were investigated by first-principles-based kinetic Monte Carlo simulation over three-dimensional Pt nanoparticles. Model platinum nanoparticles with diameters ranging from 2.3 to 4.6 nm were constructed using a truncated octahedral cluster consisting of a two (100) facets and eight (111) facets. First-principles density functional theory (DFT) calculations were used to calculate the intrinsic kinetic parameters including the binding energies for all of the surface intermediates as well as the activation barriers and reaction energies that comprise the reaction nanoparticle. Both intra- and inter-facet diffusion of adsorbates were included to model surface diffusion effects over the particle surface. The simulation results show that under lean conditions where there is excess oxygen, NO reduction to N2 occurs solely on the (100) facets. The oxidation of NO to NO2, while much more favored on the (111) facets, can occur on both (100) and (111) facets. Only small amounts of N2O form over the (100) facets. The simulated apparent activation energies for N2 and NO2 formation over the entire particle are 45 and 42 kJ/mol, respectively. The latter is in agreement with experimentally measured value of 39 kJ/mol [Mulla, S.S., et al., Catal. Lett. 2005, 100, 267]. The effects of particle size on the activities of NO reduction to N2 and NO oxidation to NO2 depend upon the ratios of exposed surface sites. For the three-dimensional model Pt nanoparticles examined here, the fractions of the (100) terrace sites are similar while the fraction of the (111) terrace sites increases with increasing particle size. As a result, the activity for NO reduction is somewhat insensitive to the particle size which symmetrically increases the numbers of (111) and (100) facets as the size increases. NO reduction, however, increases much more dramatically when the number of the (100) sites increases over the (111) sites. NO oxidation activity, on the other hand, appears to increase with increasing particle size regardless of the symmetry or shape of the particle as the reaction occurs predominantly over the (111) sites but can also take place on the (100) terrace sites. The structure insensitivity for NO oxidation is consistent with experimental results.
ISSN :	0888-5885
En ligne :	http://digital.library.unt.edu/ark:/67531/metadc71804/

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10358-10363

Titre :	Temperature excursions during soot combustion in a diesel particulate filter (DPF)
Type de document :	texte imprimé
Auteurs :	K. Chen, Auteur ; K. S. Martirosyan, Auteur ; D. Luss, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10358-10363
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Combustion Soot
Résumé :	A major technological challenge in the operation of diesel particulate filters (DPFs) is prevention of the occasional melting of the ceramic filters during regeneration (combustion of accumulated particulate matter). The cause of this melting is still an established question. Experiments and simulations indicate that during stationary regeneration (fixed feed conditions) the temperature rise is not sufficiently high to cause this melting. We conjecture that the melting is due to a transient temperature excursion caused by a rapid shift of a car from normal driving to idle during regeneration. Infrared imaging was used to follow the response of the spatiotemporal temperature on a planar DPF to sudden changes in the feed conditions. As conjectured, the peak transient temperature was higher than that corresponding to stationary operation under either the initial or final conditions. The amplitude of the temperature excursion was sensitive to the direction in which the temperature front moved and to the period between the initiation of the temperature front and the change in the feed conditions.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447927

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10348-10357

Titre :	Dynamics of a combined DOC - NSRC - SCR exhaust gas aftertreatment system with periodic regenerations
Type de document :	texte imprimé
Auteurs :	Frantisek Plat, Auteur ; Sarka Bartova, Auteur ; Jan Stepanek, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10348-10357
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Exhaust gas Selective catalytic reduction Dissolved organic carbon
Résumé :	A combined exhaust gas aftertreatment system, consisting of a diesel oxidation catalyst (DOC), an NOx storage and reduction catalyst (NSRC, which also is called lean NO, trap, LNT), and a catalyst for selective catalytic reduction of NO, by NH3 (NH3-SCR) is studied experimentally. The catalyst samples are placed in series in an almost isothermal laboratory minireactor. Dynamic behavior of the system is examined under periodic lean/rich operation in temperature range of 200-400 °C with varying composition of the rich mixture, containing CO, H2 and C3H6. Concentrations of gas components are measured at the inlet, outlet, and between the individual catalysts. The individual DOC, NSRC, SCR, NSRC-SCR, and DOC-NSRC subsystems are also examined. The DOC is used as the first element in the exhaust aftertreatment line. It is responsible for the oxidation of CO and unburned hydrocarbons (HC), and it also supports the oxidation of NO to NO2. NSRC and SCR converters are employed for the abatement of nitrogen oxides. A significant amount of NH3 can be formed in the NSRC as a byproduct of the NO, reduction, depending on the regeneration phase length, temperature, and gas composition. The generated ammonia is adsorbed in the SCR and used for additional NO, reduction. The dynamics of the combined system is investigated, and the conversions, selectivities, and reaction mechanisms in each converter, as well as mutual synergic and competitive effects, are discussed.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447926

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10341-10347

Titre :	Basic reaction model of automobile exhaust gas treatment over Pt — Rh catalyst
Type de document :	texte imprimé
Auteurs :	Motoaki Kawase, Auteur ; Hiroyasu Fujitsuka, Auteur ; Hitoshi Nakanishi, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10341-10347
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Catalyst Exhaust gas Modeling
Résumé :	A reaction model, which is comprehensive and simple enough to be a base of the dynamic model, of the after-treatment of automobile exhaust gas was proposed. The studied catalyst was Pt- and Rh-supported alumina washcoated over a honeycomb. For attaining a short residence time, a small reactor, 2-73 mm long, was employed. To formulate the reaction rate, the subsets of reactions, CO oxidation, C3H6 oxidation, and N2O and NO reduction by CO or C3H6, were carried out separately over a wide range of gas composition at 140-340 °C. An overall model was built by combining the subset models. The results calculated with the proposed model well represented the experimental results.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447925

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10334-10340

Titre :	Estimation of Effective diffusivity of stored NOx in the barium phase of Pt / BaO / Al2O3 catalysts using TAP
Type de document :	texte imprimé
Auteurs :	Ashok Kumar, Auteur ; Michael P. Harold, Auteur ; Vemuri Balakotaiah, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10334-10340
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Catalyst Diffusion coefficient
Résumé :	A systematic study over Pt/BaO/Al2O3 powder catalyst is carried out using Temporal Analysis of Products (TAP) to estimate the effective diffusivity of stored NO, in the barium phase. The prenitration of PtBaO/ Al2O3 using sequential pulses of NO, followed by reduction with H2 results in the evolution of N2 and NH3. The reduction is carried out in the NOx transport limited regime in which diffusion of the stored NO, from BaO storage phase to Pt/BaO interface was determined to be the rate controlling process. The effluent profiles of N containing species (2N2 + NH3) were used to estimate stored NO, diffusivity in barium phase and the apparent activation energy. The activation energy (74-81 kJ/mol) is in good agreement with the estimated value of 75 kJ/mol from a recent NO, trap modeling study.1.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447924

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10323-10333

Titre :	Appraisal of a De - NOx system based on H2 for light - duty diesel engine vehicles
Type de document :	texte imprimé
Auteurs :	Samir Bensaid, Auteur ; Edoardo Merlone Borla, Auteur ; Nunzio Russo, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10323-10333
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Diesel engine
Résumé :	The present paper describes a novel, fully integrated after-treatment system based on the use of hydrogen for de-NOx purposes, designed for light-duty diesel engine applications. Hydrogen is generated by an autothermal reformer, placed as a bypass unit of the close-coupled DOC and DPF, and it promotes an NO, reduction in a specific catalytic converter in the under-floor position. The results of the tests on commercial reforming catalysts and on H2-selected catalytic reductions (SCR) perovskite catalysts that were synthesized by our group are presented. The best catalyst, on the basis of TPRe activity tests, was La0.8Sr0.2Fe0.9Pd0.1O3. At a lab-scale, the fuel penalty of the system is around 4% for an NOx to N2 conversion of 60%, under the best operating conditions. T50 is very low (150 °C) compared to other de-NO, strategies. The system was then integrated on board a vehicle, and several testing protocols were performed (NEDC2000 cycle, stationary driving conditions on the roller test bench, and real driving conditions on the road). It has been demonstrated that the system is able to work independently in many driving conditions and that the reforming reaction can be effectively controlled and maintained. The NOx emissions were kept below Euro 6 levels, even though undesired CO and HC secondary emissions were produced. This performance was reached with a fuel penalty of 10%. Although this value is presently too high to envisage direct application on the market, it has been demonstrated that this technology is already fully functional on board a real vehicle, which encourages further refining research activity.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447923

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10311-10322

Titre :	Spatially - resolved temperature and gas species changes in a lean- burn engine emissions control catalyst
Type de document :	texte imprimé
Auteurs :	April Russell, Auteur ; William S. Epling, Auteur ; Howard Hess, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10311-10322
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Catalyst Pollution abatement
Résumé :	Infrared thermography and spatially resolved capillary inlet mass spectrometry (SpaciMS) have been used to characterize propylene oxidation reactions occurring along a Pt/Al2O3 monolith-supported catalyst before and after heterogeneous thermal degradation, with the heterogeneous aging being more representative of real-world conditions. The combined techniques clearly show reaction location and, therefore, catalyst use and how these change with thermal aging. Following the inhomogeneous aging, the reaction zones at steady state were broader and located farther into the catalyst relative to those observed with the fresh catalyst. In addition, the time for the temperature and concentration waves to travel through the catalyst during back-to-front ignition increased. These effects were more pronounced with lower propylene concentrations. Such trends could not be detected on the basis of standard catalyst-outlet measurements. The light-off behavior was also impacted by the aging, resulting in complex changes to the temperature front propagation, depending on the propylene concentration.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447922

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10303-10310

Titre :	Loading and aging effects in exhaust gas after - treatment catalysts with Pt As active component
Type de document :	texte imprimé
Auteurs :	Willi Boll, Auteur ; Steffen Tischer, Auteur ; Olaf Deutschmann, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10303-10310
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Catalyst Exhaust gas Loading
Résumé :	Abatement of pollutant emissions over platinum-containing catalytic converters of lean operated engines is studied. Several close-to-production model catalysts with varying platinum loading and hydrothermal aging procedures are characterized by BET, HR-SEM, HR-TEM, and CO-TPD. Pollutant conversion is numerically investigated in an isothermal flat bed reactor using varying lean exhaust-gas mixtures and temperatures. The performance of the monolithic catalysts is modeled by a two-dimensional flow field description of a single channel coupled with models for washcoat diffusion and multistep reaction mechanisms. An optimizing procedure is presented which allows adaption of kinetic parameters for slightly different catalysts. The catalytic active surface area of the catalyst determined by CO-TPD can serve as parameter to model the varying noble metal loading and consequences of hydrothermal aging without any adaption of the kinetic data included in the reaction mechanism.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447921

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10297-10302

Titre :	Optimization Design for DTB Industrial Crystallizer of Potassium Chloride
Type de document :	texte imprimé
Auteurs :	Xingfu Song, Auteur ; Menghua Zhang, Auteur ; Jin Wang, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10297-10302
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Crystallizer Design Optimization
Résumé :	A computational fluid dynamics (CFD) model was developed for the simulation and optimization of an existing continuous DTB crystallizer with KCl productivity of 0.1 million tons per year. The multiple reference frame (MRF) method was used in the CFD simulation. Both the hexagonal grid and the tetrahedral grid were adopted to divide meshes in this industrial DTB crystallizer, and in total 866 388 cells were used for CFD simulation. The fluid flow field in the DTB crystallizer was calculated using FLUENT6.3 software with the Reynolds-averaged Navier-Stokes equation combined with the widely used κ―ε turbulence model. The crystal size distribution and the coefficient of variation of crystal product were studied by CFD simulation of two-phase flow model. The impeller shapes and various operating conditions were optimized to reduce the energy consumption of the crystallization process and to increase the KCl product quality. Based on the CFD optimization design, a new impeller was retrofitted into an existing continuous DTB crystallizer with the KCl productivity of 0.1 million tons per year located at Qinghai salt lake plant in China, and its excellent performance was confirmed against data collected using the original impeller.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447920

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10287–10296

Titre :	Process intensification of reactive distillation for the synthesis of n - propyl propionate : The effects of microwave radiation on molecular separation and esterification reaction
Type de document :	texte imprimé
Auteurs :	Ernesto Altman, Auteur ; Georgios D. Stefanidis, Auteur ; Thomas Van Gerven, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10287–10296
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Esterification Microwave Distillation with reaction
Résumé :	An envisioned reactive distillation (RD) process for the esterification reaction of n-propyl propionate (ProPro) from I-propanol (ProOH) and propionic acid (ProAc) using microwave irradiation (MW) (f = 2.45 GHz) is studied. In this frame, the fundamental research performed is divided in two parts comparing reaction conditions and equilibrium curves under MW and conventional heating, looking for possible improvement in process efficiency. For the test system, the use of microwaves docs not improve the conversion of the esterification reaction catalyzed by selected zeolite catalysts possibly because microwaves are dissipated in the liquid phase before they interact with the zeolites. Concerning molecular separation, however, it was found that when the vapor-liquid interface is exposed to microwaves, the system can be disturbed from conventional equilibrium conditions and a positive deviation in phase composition can be achieved, as the vapor phase becomes richer in the component with the lower boiling temperature; the extent of separation improvement depends on the boiling points and the dielectric properties of the mixture components. This finding may have significant practical impact as it implies smaller columns with a lower number trays for a given separation efficiency, compared to conventional designs involving heat exchange in the reboiler and the condenser only. It is stressed, though, that the effect is present only when the vapor—liquid interface is exposed to microwaves; no effect is observed when solely the bulk liquid volume is irradiated.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447919

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10279-10286

Titre :	Fluidized-Bed Reactor for the Intensification of Gas-Phase Photocatalytic Oxidative Dehydrogenation of Cyclohexane
Type de document :	texte imprimé
Auteurs :	Vincenzo Palma, Auteur ; Diana Sannino, Auteur ; Vincenzo Vaiano, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10279-10286
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Dehydrogenation Oxidation Photocatalysis Fluidized bed reactor
Résumé :	The behavior of a two-dimensional laboratory-scale fluidized-bed catalytic reactor for the photocatalytic oxidative dehydrogenation of cyclohexane to benzene has been studied, employing a molybdenum-based catalyst and a titania-alumina mixed oxide as a support. A preliminary mathematical model is proposed for the evaluation of the effect of the main factors that affect the overall reactor performances. Experimental data evinced that the reaction rate is not dependent on the oxygen concentration; instead, it depends on cyclohexane concentration, according to Langmuir―Hinshelwood (LH)-type kinetics. Taking into account that the interaction between photoexcited molybdate and adsorbed cyclohexane is the rate-limiting step, the functionality in light intensity was found. The mathematical model describes the performance of the photocatalytic fluidized-bed reactor well for all operating conditions examined.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447918

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10274-10278

Titre :	Synthesis and Isolation of Methyl Acetate through Heterogeneous Catalysis with Liquid−Liquid Extraction
Type de document :	texte imprimé
Auteurs :	Susanne Lux, Auteur ; Thomas Winkler, Auteur ; Matthaus Siebenhofer, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10274-10278
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Liquid liquid extraction Heterogeneous catalysis
Résumé :	Formation of azeotropic mixtures may cause difficulties in separation. Synthesis and isolation of methyl acetate is a representative example for formation of azeotropic product mixtures. In this project chemical reaction engineering in batch and plug flow reactor, as well as the combination of synthesis with extractive isolation of methyl acetate from the multi component mixture methanol/acetic acid/methyl acetate/water, were investigated. Reaction paths were discussed in order to avoid or bypass the low boiling azeotropic mixtures of methyl acetate with water and methanol. The esterification reaction was heterogeneously catalyzed with cation exchange resins. For extractive separation of methyl acetate aliphatic hydrocarbons of the C8 to C10 class were used. The project provides the basic strategy for process design of esterification processes. In the concept of process intensification, alternative process routes in methyl acetate synthesis and isolation were discussed.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447917

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10262-10273

Titre :	Development of a continuous emulsion copolymerization process in a tubular reactor
Type de document :	texte imprimé
Auteurs :	Antonio C. S. M. Carvalho, Auteur ; Dennis L. Chicoma, Auteur ; Reinaldo Giudici, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10262-10273
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Tubular reactor Emulsion copolymerization
Résumé :	This contribution describes the development of a continuous emulsion copolymerization processs for vinyl acetate and n-butyl acrylate in a tubular reactor. Special features of this reactor include the use of oscillatory (pulsed) flow and internals (sieve plates) to prevent polymer fouling and promote good radial mixing, along with a controlled amount of axial mixing. The copolymer system studied (vinyl acetate and butyl acrylate) is strongly prone to composition drift due to very different reactivity ratios. An axially dispersed plug flow model, based on classical free radical copolymerization kinetics, was developed for this process and used successfully to optimize the lateral feeding profile to reduce compositional drift. An energy balance was included in the model equations to predict the effect of temperature variations on the process. The model predictions were validated with experimental data for monomer conversion, copolymer composition, average particle size, and temperature measured along the reactor length.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447916

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10254-10261

Titre :	Toward an Integrated Ceramic Micro-Membrane Network : Effect of Ethanol Reformate on Palladium Membranes
Type de document :	texte imprimé
Auteurs :	Daejin Kim, Auteur ; David Donohue, Auteur ; Bhanu Kuncharam, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10254-10261
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Ceramic materials
Résumé :	Our research group has developed a cartridge-based, ceramic microchannel system capable of integrating multiple unique chemical processes within a single monolithic system, for rapid heat and mass transfer. In this manuscript, the authors report on the performance of palladium thin films incorporated within this ceramic microchannel system and their chemical compatibility with ethanol reforming chemistry. A dense, ∼9-μm-thick palladium membrane for hydrogen purification from ethanol reformate was developed on a cordierite extruded ceramic support coated with successive alumina layers, and its compatibility was investigated via exposure to carbon dioxide, carbon monoxide, oxygen, water, and ethanol. The hydrogen permeability was determined to be 1.73 x 10―9 mol m―1 s―1 Pa―0.5 at 350 °C with an activation energy of 7.3 kJ mol―1 over the range 350-550 °C. Exposure to carbon dioxide and oxygen had no effect on hydrogen permeation, while carbon monoxide and water exposure resulted in a 12% and 14% decrease in hydrogen flux, which was fully recovered upon the removal of contaminants. Exposure to ethanol vapor caused a 41% drop in hydrogen flux, which was restored to 91% of the initial steady-state value upon ethanol removal, indicating an irreversible surface modification of the palladium film, in addition to competitive adsorption. The hydrogen/helium selectivity of the membrane remained in excess of 1000:1 throughout all exposure tests, verifying the suitability of this system for integrated hydrogen purification and ethanol reforming.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447915

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10251-10253

Titre :	Design of an Oxygen Reduction Catalyst for Direct Methanol Fuel Cells
Type de document :	texte imprimé
Auteurs :	Jing Xu, Auteur ; Jinhua Yang, Auteur ; Jim Yang Lee, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10251-10253
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Fuel cell Catalyst Conception
Résumé :	First principle calculations were used to screen the activity of core-shell oxygen reduction reaction (ORR) electrocatalysts for use in direct methanol fuel cells (DMFCs). Density functional theory (DFT) calculations indicate that the subsurface addition of 3d transition metals improves the activity of a Pd3Pt electrocatalyst by reducing its oxygen binding energy. Optimal activity close to the maximum of the ORR volcano curve is predicted for Pd3Fe@Pd3Pt and Pd3Mn@Pd3Pt core-shell catalysts. To validate the theoretical predictions, a series of Pd3M@Pd3Pt/C electrocatalysts (M = Ni, Co, Fe, and Cr) was prepared by galvanic replacement. Optimal activity and high methanol tolerance were observed for Pd3Fe@Pd3Pt. Compared with commercial Pt catalysts, the Pd3M@Pd3Pt structured catalysts utilize less platinum and yet display favorable ORR activity and selectivity.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447914

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010)

Titre :	Methanol steam reforming in Pd − Ag membrane reactors : Effects of reaction system species on transmembrane hydrogen flux
Type de document :	texte imprimé
Auteurs :	Sameer H. Israni, Auteur ; Michael P. Harold, Auteur
Année de publication :	2011
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Membrane reactor Steam reforming
Résumé :	The objective of this study is to understand and quantify the effects of the reactant and product species of the methanol steam reforming reaction (CH3OH, H2O, CO2, CO) on the H2 flux through a Pd77Ag23 membrane. Various concentrations of said gases along with H2 were fed to a membrane separator apparatus containing a 3.9 μm thick Pd—Ag (23 wt % Ag) "nanopore" membrane. The decrease in H2 flux through the membrane due to the presence of these gases was quantified at different temperatures (225-300 °C) and pressures (3―5 bar). The data show that CO causes the largest drop in H2 flux while H2O has the least effect. A mechanistically based adsorption and reaction model was developed to quantify the fractional surface coverages of the non-H2 species. Estimates of surface parameters such as adsorption equilibrium constants and binding energies are consistent with literature values. The adsorption model was incorporated into a two-dimensional separator model that accounted for concentration polarization (radial transport) effects. The model simulations successfully captured most of the trends in the flux data. The developed flux model is suitable for incorporation into a Pd-Ag membrane reactor model in order to evaluate the potential of a methanol membrane reformer for coupled hydrogen generation and purification.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447913

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10237–10241

Titre :	Molten - metal electrodes for solid oxide fuel cells
Type de document :	texte imprimé
Auteurs :	A. Jayakumar, Auteur ; J. M. Vohs, Auteur ; R. J. Gorte, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10237–10241
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Electrodes Fuel cells
Résumé :	Molten In, Pb, and Sb were examined as anodes in solid oxide fuel cells (SOFC) that operate between 973 and 1173 K. The results for these metals were compared with those reported previously for molten Sn electrodes. Cells were operated under “battery” conditions, with dry He or N2 flow in the anode compartment, to characterize the electrochemical oxidation of the metals at the yttria-stabilized zirconia (YSZ)-electrolyte interface. In most cases, the open-circuit voltages (OCVs) were close to that based on equilibrium between the metals and their oxides. With Sn and In, the cell impedances increased dramatically at all temperatures after drawing current due to formation of insulating, oxide barriers at the electrolyte interface. Similar results were observed for Pb at 973 and 1073 K, but the impedance remained low even after PbO formation at 1173 K because this is above the melting temperature of PbO. Similarly, the impedances of molten Sb electrodes at 973 K were low and unaffected by current flow because of the low melting temperature of Sb2O3. The potential of using molten-metal electrodes for direct-carbon fuel cells and for energy-storage systems is discussed.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie100457t

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp.10230-10236

Titre :	Oxidative coupling of methane in a BCFZ perovskite Hollow fiber membrane reactor
Type de document :	texte imprimé
Auteurs :	Oliver Czuprat, Auteur ; Thomas Schiestel, Auteur ; Hartwig Voss, Auteur
Année de publication :	2011
Article en page(s) :	pp.10230-10236
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Membrane reactor Hollow fiber
Résumé :	A membrane reactor that incorporated hollow fiber in combination with an established catalyst was used for the oxidative coupling of methane (OCM). A perovskite membrane of the composition BaCoxFeyZrzO3-delta (BCFZ, x + y + z = 1) allows a controlled oxygen feed into the reactor over its axial length. Using this novel hollow fiber membrane reactor with a 2 wt % Mn/5 wt Na2WO4 on SiO2 catalyst as a packed bed around the fiber, oxygen separation from air and C-2 formation could be established at 800 degrees C with long-term stability. The highest C-2 selectivity of similar to 75% was observed at a methane conversion of 6% with a C2H4:C2H6 ratio of 2:1. The highest C2H4:C2H6 ratio of 4:1 and maximum C-2 yield of 17% was obtained at 50% C-2 selectivity. It is known from the literature that such results can be obtained without a catalyst in a similar membrane reactor only at temperatures 150 degrees C higher.
ISSN :	0888-5885
En ligne :	http://publica.fraunhofer.de/documents/N-146437.html

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10218-10229

Titre :	Exploiting neoteric solvents for sustainable catalysis and reaction engineering : Opportunities and challenges
Type de document :	texte imprimé
Auteurs :	Bala Subramaniam, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10218-10229
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Reaction engineering Catalysis
Résumé :	The modern refinery relies primarily on feedstocks based on fossil fuels (such as petroleum, natural gas, and coal) to produce fuels and chemicals. Several megaton catalytic processes (such as homogeneous hydroformylation of higher olefins, epoxidation of light olefins, and p-xylene oxidation to produce terephthalic acid) exist that produce the essential chemical intermediates for everyday products but present sustainability challenges with respect to reducing environmental footprints and enhancing energy efficiency. Meeting the increasing demand for such chemicals, through either fossil-based feedstock or plant-based biomass, will require the development of novel sustainable processes. This article highlights the role and promise of neoteric solvents such as compressed CO2, ionic liquids, and water, with an emphasis on gas-expanded liquids (GXLs), for the development of sustainable catalytic processes and the challenges thereof. It is also shown that chemical reaction engineering is the critical link to bring the promise of green chemistry to the marketplace.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447910

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10212-10217

Titre :	Conversion of biorenewable feedstocks : New challenges in heterogeneous catalysis
Type de document :	texte imprimé
Auteurs :	Brent H. Shanks, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10212-10217
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Heterogeneous catalysis
Résumé :	For biorenewable feedstocks to serve as a significant source of chemicals and/or fuels, the development of new chemical processes as well as biological processes will be required. However, the conversion of biorenewable feedstocks with heterogeneous catalyst-based processes provides new challenges in inorganic catalyst research and development relative to historical work with petrochemical feedstocks. These catalyst and process challenges include the need to convert highly functionalized molecules with high selectivity, to develop stable catalytic liquid—solid interfaces in which the liquid phase is commonly aqueous, to control solvent phase effects and to develop novel reaction systems. While some of these challenges will be addressed using novel catalytic materials, others will need to be overcome through design of new catalytic reaction systems. Examples of emerging research results demonstrating unique approaches that have been taken to begin to address the efficient conversion of biorenewable feedstocks to chemicals and fuels are discussed.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447909

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10200-10211

Titre :	Chemical Looping Technology and Its Fossil Energy Conversion Applications
Type de document :	texte imprimé
Auteurs :	Liang-Shih Fan, Auteur ; Fanxing Li, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10200-10211
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Energy Conversion
Résumé :	The concept of chemical looping reactions has been widely applied in chemical industries, for example, the production of hydrogen peroxide (H2O2) from hydrogen and oxygen using 9,10-anthraquinone as the looping intermediate. Fundamental research on chemical looping reactions has also been applied to energy systems, for example, the splitting of water (H2O) to produce oxygen and hydrogen using ZnO as the looping intermediate. Fossil fuel chemical looping applications had been used commercially with the steam-iron process for coal from the 1900s to the 1940s and had been demonstrated at a pilot scale with the carbon dioxide acceptor process in the 1960s and 1970s. There are presently no chemical looping processes using fossil fuels in commercial operation. A key factor that hampered the continued use of these earlier processes for fossil energy operation was the inadequacy of the reactivity and recyclability of the looping particles. This factor led to higher costs for product generation using the chemical looping processes, compared to the other processes that use particularly petroleum or natural gas as feedstock. With CO2 emission control now being considered as a requirement, interest in chemical looping technology has resurfaced. In particular, chemical looping processes are appealing because of their unique ability to generate a sequestration-ready CO2 stream while yielding high energy conversion efficiency. Renewed fundamental and applied research since the early 1980s has emphasized on improvements over earlier shortcomings. New techniques have been developed for direct possessing of coal or other solid carbonaceous feedstock in chemical looping reactors. Significant progress demonstrated by the operation of several small pilot scale units worldwide indicates that the chemical looping technology may become commercially viable in the future for processing carbonaceous fuels. This perspective article describes the fundamental and applied aspects of modern chemical looping technology that utilizes fossil fuel as feedstock. It discusses chemical looping reaction thermodynamics, looping particle selection, reactor design, and process configurations. It highlights both the chemical looping combustion and the chemical looping gasification processes that are at various stages of the development. Opportunities and challenges for chemical looping process commercialization are also illustrated.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie1005542

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp 10183–10199

Titre :	Engineering molecular transformations for sustainable energy conversion
Type de document :	texte imprimé
Auteurs :	Matthew Neurock, Auteur
Année de publication :	2011
Article en page(s) :	pp 10183–10199
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Energy Molecular Conversion
Résumé :	Future strategies for sustainable energy production will undoubtedly require processes and materials that can efficiently convert renewable resources into fuels. Nature’s enzymes can exquisitely integrate highly active catalytic centers within flexible environments that can adaptively guide reactants to products with very high activities and selectivities. They are limited, however, by their stability and ability to integrate into large scale production processes. The design of more robust heterogeneous catalytic materials that mimic the performance of enzymes, however, has been hindered by our limited understanding of how such transformations proceed. The tremendous advances in ab initio quantum mechanical methods, atomistic simulations, and high performance computing that have occurred over the past two decades, however, provide unprecedented ability to track molecular transformations and how they proceed at specific sites and within particular environments. This information together with the advances in in situ spectroscopic methods that follow such transformations can begin to enable the design of atomic surface ensembles and nanoscale reaction environments. This paper provides the author’s perspective on how theory and simulation can be used to move from current one-dimensional design efforts based on catalytic descriptors to the design of two-dimensional surfaces, three-dimensional reaction environments, and proton-coupled electron transfer systems that mimic enzymes in the transformation of molecules.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie101300c

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10159-10182

Titre :	Fuel cell engineering : Toward the design of efficient electrochemical power plants
Type de document :	texte imprimé
Auteurs :	Kai Sundmacher, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10159-10182
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Power plant Design Fuel cell
Résumé :	Fuel cells are electrochemical membrane reactors that are able to convert chemically stored energy directly to electrical energy at high thermodynamic efficiencies. The present paper summarizes the current status and the future needs in fuel cell science and engineering. In the first part, possible primary fuels, alternative fuel processing pathways, and conceptual design aspects of fuel cell systems are discussed. In the second part, important trends in the development of functional materials for the preparation of stable high-performance fuel cells with extended longevity are presented. Thereby, different types of fuel cells are discussed, namely, enzymatic fuel cells (EFCs), alkaline fuel cells (AFCs), polymer electrolyte fuel cells (PEFCs), direct methanol fuel cells (DMFCs), direct ethanol fuel cells (DEFCs), phosphoric acid fuel cells (PAFCs), molten carbonate fuel cells (MCFCs), and solid oxide fuel cells (SOFCs).
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447906

[article]
in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10154-10158

Titre :	Sustainable research, development, and demonstration (RD&D)
Type de document :	texte imprimé
Auteurs :	James R. Katzer, Auteur
Année de publication :	2011
Article en page(s) :	pp. 10154-10158
Note générale :	Chimie industrielle
Langues :	Anglais (eng)
Mots-clés :	Research and development
Résumé :	The major theme of the 21st International Symposium on Chemical Reaction Engineering (ISCRE 21) is sustainable development. Many of the critical sustainable development challenges revolve around: energy, resources, food, water, and environment. Successful developments require sustainable resource-use strategies, processes, products, and services. In addition, the major challenges that we face are long-term, massive in scale, and have high future uncertainty. Sustainable developments must work now, work in the future, not put off addressing the problem, and not disadvantage future generations. These are tall challenges. Sustainability in research, development, and demonstration (RD&D) faces these same challenges and must fit into a similar framework. CRE is an important activity contributing to all aspects of RD&D. Sustainable RD&D supports both short-term and long-term needs, provides for a broad range of options, and continuously evolves to address progress made and shifts in future needs. Sustainable RD&D must provide society and/or business a portfolio of technology options and develop the science and technology base to support their application, to seed future discoveries, and to address uncertainty. This cannot be done at the individual level but must occur at the organizational level to be truly sustainable. Approaches to achieving this are illustrated with examples of success and failure from the health, semiconductor, energy, and transportation areas.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=23447905

Industrial & engineering chemistry research / Paul, Donald R. . Vol. 49 N° 21

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