Catalogue en ligne Bibliothèque Ecole Nationale Polytechnique d'Alger

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 7130–7130

Titre :	Intrinsic kinetics study of dimethyl ether synthesis from methanol on γ-Al2O3 catalysts
Type de document :	texte imprimé
Auteurs :	Majid Mollavali, Auteur ; Fereydoon Yaripour, Auteur ; Hossein Atashi, Auteur
Année de publication :	2008
Article en page(s) :	p. 7130–7130
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Note de contenu :	Additions and corrections of vol. 47 n° 9
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8011984

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 7118–7129

Titre :	Energy and hydrogen coproduction from (Athabasca bitumen) coke gasification with CO2 capture
Type de document :	texte imprimé
Auteurs :	S. Nourouzi-Lavasani, Auteur ; F. Larachi, Auteur ; M. Benali, Auteur
Année de publication :	2008
Article en page(s) :	p. 7118–7129
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Athabasca bitumen coke CO2 capture
Résumé :	Performance and economic assessments of exploitation of Athabasca bitumen coke (ABC) have been conducted to alleviate the dependence toward natural gas in bitumen recovery and upgrading. Power and hydrogen production from ABC-fed integrated gasification with combined cycle (IGCC) with CO2 capture or sequestration islands, namely, CO2 physical absorption in the Selexol process and CO2 mineral trapping (MT) with Ca(II)-bearing natural brines from local aquifers, have been analyzed. Simulations show that production costs of power (electricity and heat) and H2 from the IGCC/Selexol process are 0.0584 $/kWhe, 0.046 $/kWhh, and 1.4 $/kg H2, which could be competitive with current natural gas technologies. IGCC/Selexol outperforms the IGCC/MT process, which is reflected in larger production costs for power and H2 due to the cost of the pH-controlling reagents.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800773a

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 7112–7117

Titre :	Numerical simulation of gas dispersion in an aerated stirred reactor with multiple impellers
Type de document :	texte imprimé
Auteurs :	Jian Min, Auteur ; Yuyun Bao, Auteur ; Lei Chen, Auteur
Année de publication :	2008
Article en page(s) :	p. 7112–7117
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Aerated tank Hollow-blade disk turbine Euler-Euler computation
Résumé :	The flow field and void fraction distribution in an aerated tank of 0.45 m diameter with a three-impeller agitator have been numerically simulated and validated against prior experimental data. An asymmetric deep hollow-blade disk turbine (BT-6) was used as bottom impeller to disperse the incoming gas, with two up-pumping, four-blade, Maxflo (MFU) hydrofoils above to ensure effective axial mixing from top to bottom of the tank. The standard Eulerian−Eulerian formulation of the k−ε turbulence model with multiple frames of reference (MFR) was used in the simulation. A population balance model (PBM) combined with a multiple size group (MUSIG) model has been implemented using the commercial CFX code. Bubble breakup and coalescence have been modeled fundamentally using isotropic turbulence theory. An alternative approach was provided by an Euler−Euler computation assuming a constant single average bubble diameter (SABD), set to 4 mm. These SABD results were compared with those predicted by the MUSIG model and also with experiment. The liquid and gas flow fields, gas void fraction distribution, average bubble diameter, and spatial distribution of bubbles of differing diameter were computed and partially compared with available experimental data. The gas void fraction distribution is strongly affected and controlled by the flow field. There is a region with very high local gas holdup near the tank wall, just above the level of the top impeller. This was correctly predicted by the MUSIG model in good agreement with the experimental results. The results when using the assumption of a single average bubble diameter did not fit the experimental data quite as well.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800490j

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 7104–7111

Titre :	Steel converter slag as a raw material for precipitation of pure calcium carbonate
Type de document :	texte imprimé
Auteurs :	Sanni Eloneva, Auteur ; Sebastian Teir, Auteur ; Justin Salminen, Auteur
Année de publication :	2008
Article en page(s) :	p. 7104–7111
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Steel converter slag Calcium carbonate Acetic acid
Résumé :	In this work we study the possibility of utilizing steel converter slag, a byproduct of steel manufacturing, for production of pure calcium carbonate. The dissolution of calcium from steel converter slag by using acetic acid as a solvent and the precipitation of pure calcium carbonate from the resulting solution were experimentally investigated. It was found that, while strong solutions of acetic acid dissolve most of the calcium from the slag, weak acetic acid solutions dissolve calcium selectively. Precipitation of any substantial amount of calcium carbonate was found to require the addition of sodium hydroxide. Calcium conversion from the solution into the precipitate was as high as 86%, and the purity of the precipitate was over 99%. The calcium carbonate particles produced at low temperatures were found to have rhombohedral particle shapes, a very high brightness (98.7%), and a small particle size (mean value of 0.6 μm).
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8004034

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 7094–7103

Titre :	Mathematical modeling of the destabilization of crude oil emulsions using population balance equation
Type de document :	texte imprimé
Auteurs :	Roberto E. P. Cunha, Auteur ; Montserrat Fortuny, Auteur ; Claudio Dariva, Auteur
Année de publication :	2008
Article en page(s) :	p. 7094–7103
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Crude oil emulsions Population balance equation
Résumé :	In this work, the stability of water-in-crude oil emulsions generated in laboratory was investigated using a phenomenological mathematical model based on the population balance equation, considering different phenomena such as the binary coalescence of water droplets, the interfacial coalescence with the resolved water phase, the diffusion of the dispersed phase, and droplet settling. The resulting population balance equation (PBE) was a nonlinear hyperbolic integro-partial differential equation, which for our particular case required numerical techniques for resolution. The PBE was converted into a system of partial differential equations using Kumar’s fixed-pivot technique. The spatial coordinate was discretized using the finite volume method and a first order upwind scheme, while the discretization of the time coordinate was based on a semi-implicit approach. On the basis of this algorithm, the mathematical model was solved against experimental results of water-in-crude oil emulsion destabilization runs, providing suited predictions of droplet size distribution profiles, and of both emulsified water and free-water volumes.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800391v

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 7081–7093

Titre :	Correlation and prediction of phase behavior of organic compounds in ionic liquids using the nonrandom two-liquid segment activity coefficient model
Type de document :	texte imprimé
Auteurs :	Chau-Chyun Chen, Auteur ; Luke D. Simoni, Auteur ; Joan F. Brennecke, Auteur
Année de publication :	2008
Article en page(s) :	p. 7081–7093
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Ionic liquids NRTL-SAC model
Résumé :	Room-temperature ionic liquids have shown great potential as media for reactions and separations. Information on how organic compounds interact with these ionic liquids is crucial in assessing their usefulness. Here, the nonrandom two-liquid segment activity coefficient (NRTL-SAC) model is used first to correlate values of infinite-dilution activity coefficients for organic compounds in ionic liquids and then to predict the phase behavior of various mixtures involving these ionic liquids. NRTL-SAC provides a robust, qualitative predictive model based on four molecular descriptors that are designed to capture molecular surface interaction characteristics: hydrophobicity, hydrophilicity, polarity, and solvation strength.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800048d

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 7072–7080

Titre :	Optimization of an artificial neural network by selecting the training function : application to olive oil mills waste
Type de document :	texte imprimé
Auteurs :	José S. Torrecilla, Auteur ; José M. Aragón, Auteur ; María C. Palancar, Auteur
Année de publication :	2008
Article en page(s) :	p. 7072–7080
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Artificial neural network Olive oil mill waste Fluidized-bed dryer
Résumé :	This article describes the selection of the training algorithm of an artificial neural network (ANN) used to model the drying of olive oil mill waste in a fluidized-bed dryer. The ANN used was a three-layer perceptron that predicts the moisture value at time t + T from experimental data (solid moisture, input air, and fluidized-bed temperature) at t time; T is the sampling time. In this study, 14 training algorithms were tested. This selection was carried out by applying several statistical tests to the real and predicted moisture values. Afterward, an experimental design was carried out to analyze the influence of the training function parameters on the ANN performance. Finally, Polak−Ribiere conjugate gradient backpropagation was selected as the best training algorithm. The ANN trained with the selected algorithm predicted the moisture with a mean prediction error of 1.6% and a correlation coefficient of 0.998.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8001205

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 7058–7071

Titre :	Numerical simulation of the gas-solid flow in three-dimensional pneumatic conveying bends
Type de document :	texte imprimé
Auteurs :	K. W. Chu, Auteur ; A. B. Yu, Auteur
Année de publication :	2008
Article en page(s) :	p. 7058–7071
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Gas-solid flow Pneumatic conveying bend
Résumé :	The laden gas−solid flow in a pneumatic conveying bend is featured with intensive gas−solid, particle−particle, and particle−wall interactions, which are however difficult to quantify experimentally. In this work, these interactions are obtained by use of a three-dimensional combined continuum and discrete model. The model is achieved by combining our code for discrete element method for solid phase with the commercial software package Fluent for computational fluid dynamics for gas phase. The applicability of the approach is first qualitatively verified by comparing the simulated results with the observations in the literature in terms of typical flow features in bends such as roping, particle segregation, particle velocity reduction, particle recirculation, and pressure fluctuation. The gas−solid, particle−particle, and particle−wall interaction forces are then analyzed to understand their role in governing the complicated flow. It is found that the intensive gas−particle interaction at the outer wall makes the peak of the axial velocity shift from the outer wall to the inner wall of a pipe. Correspondingly, the so-called secondary flow is suppressed in the outer wall region but enhanced along the side wall. The spatial distribution of particle−wall interaction is obtained and shown to correspond to the wearing pattern in a bend. This distribution is also found in the particle−particle interaction close to the bend wall. Not only gas−solid interaction but also particle−particle interaction contributes to the dispersion of a rope. Finally, simulations are also conducted to investigate the effects of inlet conditions such as gas and solid flow rates on these interaction forces.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800108c

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 7048–7057

Titre :	Motion of Taylor bubbles and taylor drops in liquid-liquid systems
Type de document :	texte imprimé
Auteurs :	Tapas K. Mandal, Auteur ; Gargi Das, Auteur ; Prasanta K. Das, Auteur
Année de publication :	2008
Article en page(s) :	p. 7048–7057
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Liquid Taylor bubbles Liquid Taylor drops Inclined tubes Vertical tubes Liquid-liquid systems
Résumé :	The present work reports an experimental study on the shape and stability of liquid Taylor bubbles and liquid Taylor drops in vertical and inclined tubes. Experiments have been performed with five liquid pairs, namely, water−kerosene, brine−kerosene, water−benzene, water−cyclohexane, and water−2-heptanone, in five different tube diameters ranging from 0.012 to 0.046 m and inclinations of 0°, 15°, 30°, 45°, 60°, and 75° with vertical. The effect of tube inclination, tube diameter, and pipe material on shape, stability, and velocity of a liquid Taylor bubbles and liquid Taylor drops has been explained qualitatively from basic physics. The existing correlations generally used for gas−liquid system have been modified to predict the rise velocity in vertical tubes.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8004429

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 7038–7047

Titre :	Performance of anticorrosive coatings containing tripolyphosphates in aggressive environments
Type de document :	texte imprimé
Auteurs :	M. Deyá, Auteur ; A. R. Di Sarli, Auteur ; B. del Amo, Auteur
Année de publication :	2008
Article en page(s) :	p. 7038–7047
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Calcium tripolyphosphate Zinc tripolyphosphate Aggressive environments
Résumé :	The objective of this research was to study the efficiency of calcium tripolyphosphate and zinc tripolyphosphate as anticorrosive pigments for paints in aggressive environments. Alkyd and epoxy paints, of the solvent-borne type, containing 30% by volume (v/v) of the pigment, were formulated. The pigment volume concentration/critical pigment volume concentration (PVC/CPVC) ratio was fixed at 0.8. In a second stage, water-borne paints containing 30% v/v of both tripolyphosphates and different PVC values (20 and 25%) were also formulated. Finally, standardized accelerated (salt spray and humidity chamber exposure) and electrochemical impedance spectroscopy (EIS) tests were used to assess the protective performance of the coatings. Analysis and interpretation of the experimental data show that both, calcium and zinc tripolyphosphates, inhibit corrosion of painted steel panels exposed to aggressive environments.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie071544d

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 7031–7037

Titre :	Hemicellulose extraction of mixed southern hardwood with water at 150 °C : effect of time
Type de document :	texte imprimé
Auteurs :	M. Sefik Tunc, Auteur ; Adriaan R. P. van Heiningen, Auteur
Année de publication :	2008
Article en page(s) :	p. 7031–7037
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Hemicellulose Extraction Wood Hydrothermal dissolution
Résumé :	Hemicelluloses derived from biomass are presently underutilized. In order to develop more profitable biorefinery processes, the mechanism responsible for hemicellulose removal by pretreatments has to be further explored. The hydrothermal dissolution profile of the wood components cellulose, hemicelluloses, and lignin of a hardwood mixture during autohydrolysis in a modified Dionex ASE-100 is described. Well-closed material balances were obtained for lignin-free yield, xylan, and glucomannan when comparing the solid and liquid phases. Xylo-oligomers were the predominant component in the extract. Xylan initially dissolved as oligosaccharides and then slowly depolymerized into monomeric xylose. The residual xylan in wood was only slightly deacetylated. A smaller amount of glucomannan was removed as oligosaccharides. Arabinose and galactose were completely removed from wood as monomers at the end of the extraction process. Initially all acetyl groups were removed while still bound to oligosaccharides. Then, acetic acid was released by deacetylation of the dissolved oligosaccharides.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8007105

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 7027–7030

Titre :	Liquid-phase guard bed for removal of synthesis gas contaminants
Type de document :	texte imprimé
Auteurs :	Robert Quinn, Auteur ; Bernard A. Toseland, Auteur
Année de publication :	2008
Article en page(s) :	p. 7027–7030
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Guard bed Methanol synthesis
Résumé :	This article describes a single guard bed that is effective for the removal of all poisons from a methanol synthesis process. The guard bed consists of a methanol synthesis catalyst suspended in a nonreactive liquid (a liquid-phase guard bed). The key to making the guard bed universal is operating the guard bed at a temperature below the operating temperature of the reactor but at a sufficiently high temperature and residence time to allow achievement of equilibrium with the incoming gas. The successful use of this guard bed is demonstrated for several catalyst poisons. In addition, the use of spent catalyst for the guard bed is demonstrated.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8003418

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 7019–7026

Titre :	Adsorption equilibrium and kinetics of water vapor on different adsorbents
Type de document :	texte imprimé
Auteurs :	Ana M. Ribeiro, Auteur ; Ticiane P. Sauer, Auteur ; Carlos A. Grande, Auteur
Année de publication :	2008
Article en page(s) :	p. 7019–7026
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Water vapor Kinetic data Adsorption equilibrium Zeolite Activated carbon
Résumé :	Water vapor needs to be removed from many industrial streams using, for example, adsorption processes. Equilibrium and kinetic data are essential for the design of these adsorption processes. In this work, the adsorption equilibrium isotherms of water vapor were measured at 303 K by a gravimetric system on three commercial adsorbents, an activated carbon, an activated alumina, and a zeolite. The zeolite sample presented the highest capacity at low relative pressures, while at pressures near saturation the higher amount adsorbed was obtained on the alumina sample. The experimental points obtained for the activated carbon and the zeolite were fitted with the Virial isotherm while the n-layer BET equation was used in the fitting of the alumina data. The adsorption kinetics was evaluated through the analysis of breakthrough curves obtained at the same temperature for different feed humidity values. The fixed bed behavior was described using an isothermal model that includes axial dispersion and external (film model) and internal (homogeneous LDF model) mass transfer resistances. The homogeneous diffusivity values were determined by adjusting the model to the experimental data.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie701732x

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 7013–7018

Titre :	Isolation and purification of fatty acid steryl esters from soybean oil deodorizer distillate
Type de document :	texte imprimé
Auteurs :	Setiyo Gunawan, Auteur ; Cynthia Fabian, Auteur ; Yi-Hsu Ju, Auteur
Année de publication :	2008
Article en page(s) :	p. 7013–7018
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Soybean oil deodorizer distillate Fatty acid steryl esters Soxhlet extraction Silica gel column chromatography Solvent extraction
Résumé :	Depending on the source, deodorizer distillates usually have significantly different characteristics, uses, and value. Soybean oil deodorizer distillate (SODD) has been suggested as an alternative to marine animals as a natural source of squalene and a good raw material for the production of fatty acid steryl esters (FASEs), tocopherols, free phytosterols and fatty acids. The purpose of this work was to isolate and purify natural FASEs from SODD by a suitable method without degradation of the FASEs. Modified Soxhlet extraction, modified silica gel column chromatography, and binary solvent extraction were employed sequentially in this study to obtain FASEs from SODD. FASEs with a purity of 86.74% and a total recovery of 85.32% could be obtained in the final product.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800346x

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 7005–7012

Titre :	Interpretation of CO2 Solubility and Selectivity in Nitrile-Functionalized Room-Temperature Ionic Liquids Using a Group Contribution Approach
Type de document :	texte imprimé
Auteurs :	Trevor K. Carlisle, Auteur ; Jason E. Bara, Auteur ; Christopher J. Gabriel, Auteur
Année de publication :	2008
Article en page(s) :	p. 7005–7012
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Room-temperature ionic liquids Solubility parameters
Résumé :	In this work, tuning the solubility parameter of room-temperature ionic liquids (RTILs) with appended functional groups was explored using a combination of experiment and theory. By predictably altering the solubility parameters of several RTIL solvents, their gas solubility and separation performance were tailored. This concept was demonstrated by synthesizing and characterizing imidazolium-based RTILs that incorporate nitrile and alkyne functional substituents. The ideal solubility and selectivity values of CO2, N2, and CH4 at near ambient temperature and pressure were measured for these RTILs. These functionalized RTIL solvents exhibited lower CO2, N2, and CH4 solubility values but improved CO2/N2 and CO2/CH4 solubility selectivity when compared to analogous nonfunctionalized, n-alkyl-substituted RTILs. A group contribution method was used to predict the solubility parameters of the functionalized RTILs, and these values were used with regular solution theory to predict the solubility and selectivity of the three gases. These predicted gas solubility values were found to be in good agreement with those measured experimentally. Furthermore, the predictions from the group contribution method indicated that inclusion of the nitrile and alkyne functional groups increased the solubility parameter relative to the analogous, n-alkyl-substituted RTILs. These initial results show that the group contribution method offers a valuable guide for systematically designing functionalized RTILs with specific gas solubility and selectivity performance.
En ligne :	http://pubs.acs.org/doi/http://pubs.acs.org/doi/abs/10.1021/ie8001217abs/10.1021 [...]

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 6999–7004

Titre :	Analysis of fixed-bed column adsorption of reactive yellow 176 onto surfactant-modified zeolite
Type de document :	texte imprimé
Auteurs :	Aysegul Faki, Auteur ; Mustafa Turan, Auteur ; Ozgur Ozdemir, Auteur
Année de publication :	2008
Article en page(s) :	p. 6999–7004
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Reactive Yellow 176 onto zeolite Adsorption Fixed-bed column system
Résumé :	Adsorption of Reactive Yellow 176 onto zeolite in a fixed-bed column system was investigated. To increase the adsorption capacity, we modified the surface of natural zeolite with a cationic surfactant (HTAB). The adsorption tests consisted of the modification of zeolite with HTAB followed by the dye removal in the column. The zeolite that was modified at 3 g/L HTAB concentration showed the best performance in adsorbing the yellow dye. The column with a 3 cm diameter and different bed heights of 25, 35, and 50 cm treated 24, 36, and 66 L at the breakthrough point, respectively, for 50 mg/L Reactive Yellow 176 dye solution at a flow rate of 0.050 L/min. The bed depth service time (BDST) model proved to be effective in the comparison of column variables. The minimum bed height, the adsorption rate constant, and the adsorption capacity of the HTAB modified zeolite for yellow dye removal were found to be 12.02 cm, 6.432 × 10−3 L/(mg h), and 12.05 g/L, respectively. Color removal efficiencies of the simulated and real textile wastewaters were evaluated and adsorption capacity in the simulated textile wastewater and the real textile wastewater showed 25 and 62% decrease compared to the yellow dye solution. The column regeneration was also evaluated using a solution consisting of 30 g/L NaCl and 1.5 g/L NaOH with a pH value of 12 at 25 cm bed height with a flow rate of 0.050 L/min at temperatures 30 and 60 °C. Desorption efficiency increased from 23 to 90.6% with the increase in temperature from 30 to 60 °C.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800097k

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 6991–6998

Titre :	Spectroscopic monitoring of carbamazepine crystallization and phase transformation in ethanol-water solution
Type de document :	texte imprimé
Auteurs :	Haiyan Qu, Auteur ; Jarno Kohonen, Auteur ; Marjatta Louhi-Kultanen, Auteur
Année de publication :	2008
Article en page(s) :	p. 6991–6998
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Anhydrate/hydrate Crystallization Carbamazepine Ethanol-water solutions
Résumé :	The crystallization mechanism of anhydrate/hydrate has to be understood in order to control the hydration state of an active pharmaceutical ingredient. In the present work, the formation of the anhydrous (CBZA) and dihydrate (CBZH) form of carbamazepine (CBZ) in ethanol−water solutions was studied by simultaneous monitoring of both the anhydrate/hydrate phase of the crystals and the CBZ concentration in the mother liquor with the Raman immersion probe. Two different cooling strategies and the effect of one surfactant were studied. The information obtained from the Raman spectroscopy indicated that the thermodynamic factor was dominated in determining the anhydrate/hydrate form of the crystals in the studied system. The thermodynamically stable form was obtained in all studied crystallization conditions. The presence of a surfactant additive showed a slight promotion effect only on the phase transformation of CBZA to CBZH. The results obtained in the present work lead to improved understanding of the formation mechanism of anhydrate/hydrate in aqueous solution.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie071642z

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 6983–6990

Titre :	Set-point weighted PID controller tuning for time-delayed unstable processes
Type de document :	texte imprimé
Auteurs :	Chan-Cheng Chen, Auteur ; Hsia-Ping Huang, Auteur ; Horng-Jang Liaw, Auteur
Année de publication :	2008
Article en page(s) :	p. 6983–6990
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	PID controller Error feedback Nonerror feedback
Résumé :	The set-point weighted proportional, integral, and derivative (PID) controller has been shown to be equivalent to an error feedback PID controller with a PD controller in the inner loop; and, many nonerror feedback designs have been unified under the frame of tuning the set-point weighted PID controller. A simple method is then proposed to reform an existing PID control system into a set-point weighted PID control system for unstable processes. To reform an existing error feedback PID control system into the set-point weighted PID control system, the proposed method needs neither the information of the process nor the information of the design methods of the original error feedback PID control system. The only information needed to reform the existing PID control system is the values of the tuning parameters of the original error PID control system. Theoretical analysis shows that if the original error feedback PID control system is stable, the stability of the proposed set-point weighted PID control system is guaranteed automatically. Simulation results show that the performance of the proposed set-point weighted PID control system can be effectively enhanced in comparison with that of the original error feedback PID control system; further, this performance of the proposed set-point weighted PID control system is comparable to that of many other nonerror feedback systems reported in the literature.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800001m

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 6972–6982

Titre :	Application of principal component analysis for monitoring and disturbance detection of a hydrotreating process
Type de document :	texte imprimé
Auteurs :	Stella Bezergianni, Auteur ; Aggeliki Kalogianni, Auteur
Année de publication :	2008
Article en page(s) :	p. 6972–6982
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Principal component analysis Multivariate process
Résumé :	Principal component analysis (PCA) is a well-established technique for monitoring and disturbance detection of multivariate process, as it enables variability assessment through dimensionality reduction. PCA was applied to a hydroprocessing pilot plant to monitor the overall process variability. Contribution plots around points of increased variability were used to analyze process variability and its association with process variables. The methodology monitored successfully the set of 38 variables and diagnosed significant disturbances and their causes.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie0714605

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 6961–6971

Titre :	Fault detection and diagnosis of nonlinear processes using improved kernel independent component analysis (KICA) and support vector machine (SVM)
Type de document :	texte imprimé
Auteurs :	Yingwei Zhang, Auteur
Année de publication :	2008
Article en page(s) :	p. 6961–6971
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Kernel independent component analysis Fault detection
Résumé :	In this article, the nonlinear dynamic process monitoring method based on kernel independent component analysis (KICA) is developed. Compared to the Support Vector Machine (SVM) method, KICA is unsupervised and available for fault detection. Hence, in this article, KICA is used to detect faults. Because the dimension of the feature space is far less than the rank of kernel matrix, a basis in feature space is selected. Specifically, the basis in feature space is first constructed based on the similarity factor of data in one group in this article. A contribution plot is impossible, because the nonlinear mapping function from input space into feature space is unknown. Therefore, KICA is difficult for nonlinear fault diagnosis. In this article, once a fault is detected, the kernel-transformed scores from improved KICA will be directly introduced as the inputs of SVM to diagnose the fault. The classification rate of SVM plus improved KICA is higher than the classification rate of SVM plus KICA when the same number of independent components (nICs) is selected. The reason is that the negentropy in improved KICA plus SVM could take into account the more-useful information of original inputs than that of original KICA plus SVM. The training time of SVM plus improved KICA is shorter than that of SVM plus KICA, because the former attenuates the expensive computation load. The proposed approach is applied to the fault detection and diagnosis in the Tennessee Eastman process and a wastewater treatment process (WWTP). Applications indicate that the proposed approach effectively captures the nonlinear dynamic in the process variables and shows superior fault detectability, compared to conventional methods.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie071496x

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 6949–6960

Titre :	Nonlinear model predictive control of reactive distillation based on stochastic optimization
Type de document :	texte imprimé
Auteurs :	Ch. Venkateswarlu, Auteur ; A. Damodar Reddy, Auteur
Année de publication :	2008
Article en page(s) :	p. 6949–6960
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Stochastic optimization algorithms Nonlinear model predictive control Nonlinear input-output process Single input-single output control
Résumé :	Stochastic optimization algorithms such as genetic algorithm (GA) and simulated annealing (SA) are combined with a polynomial-type empirical process model to develop nonlinear model predictive control (NMPC) strategies, namely, GANMPC and SANMPC, in the perspective of control of a nonlinear reactive distillation column. In these strategies, the nonlinear input−output process model is cascaded itself to generate future predictions for the process output based on which the control sequence is computed by stochastic optimizers while satisfying the specified performance criteria. The performance of the proposed controllers is evaluated by applying to single input−single output (SISO) control of an ethyl acetate reactive distillation column with double-feed configuration involving an esterification reaction with azeotropism. The results demonstrate better performance of the stochastic optimization based NMPCs over a conventional proportional−integral (PI) controller, a linear model predictive controller (LMPC), and a NMPC based on sequential quadratic programming (SQP) in tracking the setpoint changes as well as stabilizing the operation in the presence of input disturbances. Although both the GANMPC and SANMPC are found to exhibit almost equal performance, the easier tuning and the lower computational effort suggests the better suitability of SANMPC for the control of a nonlinear reactive distillation column.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie070972g

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 6941–6948

Titre :	Development of a continuous manufacturing process for silica sols via the ion-exchange of a waterglass
Type de document :	texte imprimé
Auteurs :	Taeyoun Kim, Auteur ; Sungwoo Hwang, Auteur ; Sanghoon Hyun, Auteur
Année de publication :	2008
Article en page(s) :	p. 6941–6948
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Silica sol Waterglass Ion-exchange
Résumé :	The properties of aqueous colloidal silica sol synthesized by an ion-exchange in a waterglass solution were examined and a continuous manufacturing process of silica sol and regeneration was designed for producing silica sol from inexpensive starting materials in large quantities. The maximum ion-exchange capacity of resin, the ion-exchange kinetics, and the characteristics of the silica sol were evaluated. The process conditions for the continuous manufacturing process of silica sol were optimized. Silica sols synthesized by the continuous manufacturing process have silica contents in the range of 5−5.7 wt %, a pH of the sol in the range of 2.3−3.0, and a low residual sodium ion concentration. In terms of possessing a narrow deviation from the mean value of these properties, this process can manufacture reliable silica sols on a mass production level.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie071009d

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 6933–6940

Titre :	Role of water in the development of new isocyanate-based bituminous products
Type de document :	texte imprimé
Auteurs :	Maria J. Martín-Alfonso, Auteur ; Pedro Partal, Auteur ; Francisco J. Navarro, Auteur
Année de publication :	2008
Article en page(s) :	p. 6933–6940
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Bituminous membranes MDI-PEG reactive polymer
Résumé :	Asphalt, roofing, and sealing markets strongly demand new materials for being used, for instance, as bituminous coating membranes. In that sense, this paper deals with the effect on these bitumen-based composites of the addition of a MDI-PEG reactive polymer, synthesized by the reaction of 4,4′-diphenylmethane diisocyanate with a low molecular weight poly(ethylene glycol). A short-term modification, taking place during mixing, and a long-term bitumen modification, which develops for a long period of curing (up to several months), have been identified. Both of them result from chemical reactions between NCO groups in the MDI-PEG and some of the bitumen compounds, mainly, the resin fraction. However, long-term bitumen modification seems to be related to the polymer−bitumen reactions but influenced by the environmental conditions (probably due to air moisture). This fact may be used to improve the manufacture of new materials with suitable properties according to their final application.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800243w

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 6925–6932

Titre :	Electrochemical behavior of serratia marcescens ACE2 on carbon steel API 5L-X60 in organic/aqueous phase
Type de document :	texte imprimé
Auteurs :	Aruliah Rajasekar, Auteur ; Sundaram Maruthamuthu, Auteur ; Yen-Peng Ting, Auteur
Année de publication :	2008
Article en page(s) :	p. 6925–6932
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Carbon steel API 5L-X60 Diesel-water systems Serratia marcescens ACE2 Electrochemical impedance spectroscopy
Résumé :	The present study reports on the role of the bacterium Serratia marcescens ACE2 in the corrosion behavior of carbon steel API 5L-X60 in diesel−water systems. The effect of commercial corrosion inhibitor (CI) on the growth of strain ACE2 and its corrosion inhibition efficiency was investigated. The corrosion rate was evaluated using electrochemical impedance spectroscopy (EIS) and polarization techniques in the diesel−water interface systems. The amine and carboxylic acid based inhibitor gave better efficiency in the absence of strain ACE2 by suppression of both anodic and cathodic reactions. In the presence of the strain ACE2, the inhibitor suppressed the cathodic reaction more significantly than the anodic reaction. The electrochemical behavior of steel API 5L-X60 was correlated with the role of the adsorbed amine based compound and degraded product on the metal surface. The surface morphology of the coupons in the presence/absence of the inhibitor with ACE2 was observed by using atomic force microscopy (AFM) and revealed pitting corrosion. This basic study is useful for the development of new approaches for the detection, monitoring, and control of microbial corrosion in a petroleum product pipeline.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8005935

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 6917–6924

Titre :	Hydrodynamics of a multistage countercurrent fluidized bed reactor with downcomer for lime-dolomite mixed particle system
Type de document :	texte imprimé
Auteurs :	C. R. Mohanty, Auteur ; Sivaji Adapala, Auteur ; B. C. Meikap, Auteur
Année de publication :	2008
Article en page(s) :	p. 6917–6924
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Fluidized bed reactor Multistage system
Résumé :	In the present investigation, a multistage countercurrent gas−solid fluidized bed reactor with downcomer has been proposed. The basic operating parameters have been developed illustrating the mechanism of gas−solid contacting in the system. The system was operated in three stages in series one above the other in continuous regime for a two-phase system over a wide range of operating conditions including varying the weir height in order to determine the pressure drop. The data were generated under steady and stable operation of the column. The solids holdup of the proposed multistage system is higher than the single-stage system, which results in better mass-transfer characteristics. The results in this study assume importance from the standpoint of design and steady operation of a multistage fluidized bed reactor for control of gaseous pollutants. The fluidizing gas was air, and the solid phase was a mixture of dolomite and lime in varying proportions.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8007693

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 6904–6916

Titre :	Ultradeep adsorption-desulfurization of gasoline with Ni/Al-SiO2 material catalytically facilitated by ethanol
Type de document :	texte imprimé
Auteurs :	Miron V. Landau, Auteur ; Moti Herskowitz, Auteur ; Rajeev Agnihotri, Auteur
Année de publication :	2008
Article en page(s) :	p. 6904–6916
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Low-sulfur Adsorptive desulfurization Fixed bed Ni/Al-SiO2
Résumé :	Adsorptive desulfurization of low-sulfur (22 ppmw) gasoline on solids in a liquid-full (no hydrogen) fixed bed was conducted at 503 K. Addition of 3 wt % ethanol to gasoline increased significantly the adsorption rate of sulfur-containing hydrocarbons on Ni/Al−SiO2 and its sulfur capacity, leading to <0.5 ppmw residual sulfur with a sulfur capacity of 2 wt % (mass of sulfur per mass of sorbent). Three potential routes for improving desulfurization performance of Ni sorbent in the presence of ethanol and its decomposition products containing CO and hydrogen were considered: (i) formation of nickel carbide (Ni3C) phase with reactivity toward S-organic compounds higher than that of metallic nickel, (ii) reduction of carbon deposits in the presence of hydrogen, and (iii) formation of nickel sulfide nanoparticles in the presence of H2/H2S vs adsorbed sulfur/sulfur organics that block the surface of metallic nickel in the absence of EtOH (hydrogen). Catalyst characterization data (N2 adsorption, XRD, EDX, HRTEM, FTIR, XPS, AES depth profile analysis) indicated that the effect of ethanol on the desulfurization performance was a result of reduction of coke deposition and changing the sulfur uptake mode from adsorption to reactive adsorption with the formation of bulk nickel sulfide phases Ni3S2 and Ni3S4. This is facilitated by hydrogen produced from the catalytic decomposition of ethanol that participates in the desulfurization of S-organics and in the formation of nickel sulfide phases.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800590x

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 6896–6903

Titre :	Evolution with the temperature of the compounds obtained in the catalytic pyrolysis of polyethylene over HUSY
Type de document :	texte imprimé
Auteurs :	A. Marcilla, Auteur ; M. I. Beltrán, Auteur ; R. Navarro, Auteur
Année de publication :	2008
Article en page(s) :	p. 6896–6903
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Low-density polyethylene High-density polyethylene HUSY zeolite Catalytic decomposition
Résumé :	The catalytic decomposition processes of low- and high-density polyethylene (LDPE and HDPE) have been studied using HUSY zeolite as catalyst in a batch reactor under dynamic conditions. The evolution of the gaseous and condensed products evolved with respect to the temperature has been analyzed and compared to that obtained under similar conditions in the thermal pyrolysis of LDPE and HDPE. The behavior of the gases generated from both polyethylenes was similar, olefins being the more abundant species. Great changes were observed in the composition of the gases evolved at different temperatures. Isoparaffins and olefins showed two maxima at low and high temperatures, whereas the remaining compounds generated presented only one maximum at high temperatures. Analysis of condensed products revealed some differences between the two polyethylenes at the end of the process. Two maxima, one at low and another at high temperatures, appeared in the catalytic pyrolysis of HDPE, where isoparaffins and aromatics were the most abundant condensed products obtained at each maximum. However in the case of LDPE, n-paraffins were the main products at the very end of the process. These different outcomes could be related to the progressive deactivation of the zeolite.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800520u

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 6890–6895

Titre :	Deep oxidative desulfurization of fuels using peroxophosphomolybdate catalysts in ionic liquids
Type de document :	texte imprimé
Auteurs :	Lining He, Auteur ; Huaming Li, Auteur ; Wenshuai Zhu, Auteur
Année de publication :	2008
Article en page(s) :	p. 6890–6895
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Ionic liquid Catalytic oxidation ECODS system Peroxophosphomolybdates
Résumé :	A combination of catalytic oxidation and extraction in ionic liquid (IL) was used for the removal of benzothiophene (BT), dibenzothiophene (DBT), and 4,6-dimethyldibenzothiophene (4,6-DMDBT) from the model oil. Three peroxophosphomolybdates Q3{PO4[MoO(O2)2]4} (Q = [(C4H9)4N]+, [C14H29N(CH3)3]+ and [C16H33NC5H5]+) were synthesized and characterized. In the catalytic oxidation desulfurization (CODS) system containing the peroxophosphomolybdate with short alkyl chain ([(C4H9)4N]3{PO4[MoO(O2)2]4}) and H2O2, the process exhibited low sulfur removal (16.8%). However, with addition of 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF4), the extraction and catalytic oxidative desulfurization (ECODS) system remarkably increased the removal of sulfur to 97.3% (with stoichiometric amounts of H2O2). The process was superior to the simple extraction with IL (16.3%). The results demonstrated that the ECODS system could deeply remove DBT from the model oil, and this desulfurization system could be recycled 4 times with slight decrease in activity. We also found that the catalysts with short alkyl chains exhibited higher catalytic activity than that with long alkyl chain in the ECODS system. Moreover, the reactivity of sulfur compounds decreased in the order of DBT > 4,6-DMDBT > BT.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800857a

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 6885–6889

Titre :	Biodiesel production by esterification of oleic acid with methanol using a water adsorption apparatus
Type de document :	texte imprimé
Auteurs :	Izabelly L. Lucena, Auteur ; Giovanilton F. Silva, Auteur ; Fernandes, Fabiano A. N., Auteur
Année de publication :	2008
Article en page(s) :	p. 6885–6889
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Biodiesel Esterification reaction Adsorption column Methanol Water
Résumé :	The production of biodiesel was investigated using a new reaction system consisting of a reactor coupled to an adsorption column. The esterification reaction was carried out above the boiling points of methanol and water to evaporate the water produced during the reaction. A condenser placed above the adsorption column was responsible for condensing the water and methanol vapor, returning water-free methanol to the reactor after passing through the adsorption column. The adsorption system was employed to remove the water produced during the reaction to shift the equilibrium toward fatty acid methyl ester production. Biodiesel was produced by the esterification reaction of oleic acid and methanol, using sulfuric acid as catalyst. The results showed that the new reaction system yielded up to 99.7% biodiesel, while the highest yield obtained using the traditional agitated batch reactor was 88.2%. The best operating condition was found when the reactor was operated at 100 °C, 1% catalyst (w/w), and with an oleic acid to methanol ratio of 3:1.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800547h

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 6878–6884

Titre :	Reducing byproduct formation during conversion of glycerol to propylene glycol
Type de document :	texte imprimé
Auteurs :	Chuang-Wei Chiu, Auteur ; Ali Tekeei, Auteur ; Joshua M. Ronco, Auteur
Année de publication :	2008
Article en page(s) :	p. 6878–6884
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Glycerol Propylene glycol Selective conversion
Résumé :	During the conversion of glycerol to propylene glycol, highly selective conversion is necessary for commercial viability. The greatest strides in achieving high selectivity are attained with catalyst and temperature. For the conversion of glycerol to propylene glycol, these parameters can be optimized to achieve selectivities of greater than 80%. This paper is on the optimization of more-subtle parameters such as concentration, water content, pressure, isothermal operation, and residence time to achieve selectivities in excess of 90%. Data reveal that low concentrations are important to reduce by-product whose formation relies on second-order reaction mechanisms. Water is important to reduce dehydration reactions and indirectly helps to maintain more-isothermal operation. An optimal hydrogen partial pressure between 5 and 15 bar minimizes the cumulative amount of by-product that results from hydrocracking versus dehydration side-reactions.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800300a

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 6870–6877

Titre :	Alkylate technology selection for Fischer-Tropsch syncrude refining
Type de document :	texte imprimé
Auteurs :	Arno de Klerk, Auteur ; Philip L. de Vaal, Auteur
Année de publication :	2008
Article en page(s) :	p. 6870–6877
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Alkylate Fischer-Tropsch syncrude
Résumé :	Technology selection to produce alkylate from straight run Fischer−Tropsch syncrude has been investigated. Alkylate is a high octane paraffinic motor-gasoline component and can be produced by direct alkylation (olefin addition to isobutane) or indirect alkylation (isobutene dimerization followed by hydrogenation). Neither isobutane nor isobutene is abundant in the light fraction of Fischer−Tropsch syncrude, which is rich in linear alpha-olefins. Direct alkylation (HF and H2SO4) and indirect alkylation (acidic resin and solid phosphoric acid) based flowschemes were evaluated in terms of alkylate yield, octane number, compatibility to Fischer−Tropsch derived feed, and environmental friendliness. It was found that the refining focus determined the selection. Indirect alkylation with solid phosphoric acid was found to be the best in terms of Fischer−Tropsch feed compatibility, environmental friendliness, and least refining complexity. The highest alkylate yield could be obtained by a combination of partial olefin hydrogenation, hydroisomerization, and direct alkylation. Butene skeletal isomerization in combination with indirect alkylation yielded an alkylate with the highest octane number.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800288n

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 6862–6869

Titre :	Three-phase catalytic hydrogenation of a functionalized alkyne : mass transfer and kinetic studies with in situ hydrogen monitoring
Type de document :	texte imprimé
Auteurs :	Andrea Bruehwiler, Auteur ; Natalia Semagina, Auteur ; Martin Grasemann, Auteur
Année de publication :	2008
Article en page(s) :	p. 6862–6869
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Mass transfer interactions Hydrogen Catalytic hydrogenation
Résumé :	Systematic studies of mass transfer interactions with intrinsic reaction kinetics were performed for the three-phase selective hydrogenation of 2-methyl-3-butyn-2-ol (MBY) to 2-methyl-3-buten-2-ol (MBE) over a modified Pd/CaCO3 catalyst under solvent free conditions. Hydrogen concentration in the liquid phase (CH2,b) was monitored in situ during the catalytic reaction by means of the “Fugatron” analyzer. Reactions were carried out in an autoclave at different stirring rates at two concentrations of hydrogen (5 and 13 mol·m−3). For stirring speeds higher than 1500 rpm no influence of gas−liquid mass transfer was observed. Hydrogen liquid−solid (L-S) mass transfer was found to be negligible, whereas the MBY mass L-S transfer becomes important at high MBY conversions at high hydrogen concentration. Low stirrer speed caused the reaction rate and MBE selectivity to decrease. No internal mass transfer limitations were observed, and conditions for the kinetic regime were found. The kinetics modeled followed the Langmuir−Hinshelwood mechanism and was consistent with the experimental data.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800070w

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 6854–6861

Titre :	Catalytic hydrotreatment of crude waxes from different sources over a Ni-W/-Al2O3 catalyst
Type de document :	texte imprimé
Auteurs :	Jesús Sánchez, Auteur ; María Fernanda Tallafigo, Auteur ; Miguel A. Gilarranz, Auteur
Année de publication :	2008
Article en page(s) :	p. 6854–6861
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Crude wax Alumina-supported catalyst Spindle feedstock
Résumé :	The hydrotreatment of crude wax from the dewaxing of spindle, light neutral, medium neutral, heavy neutral, and brightstock oil was studied to obtain refined paraffins that are suitable for high-grade applications. The runs were performed using an alumina-supported catalyst with 5.9 wt % of nickel (as NiO) and 16.2 wt % of tungsten (as WO3) that was used for >6000 h. The ease of treatment was ranked as follows: spindle > light neutral > medium neutral > heavy neutral ≫ brightstock. The use of high temperatures and pressures was needed to obtain a convenient reduction in the color of the heavier feedstocks. Spindle feedstock required a temperature of 548 K and a pressure of 9.81 MPa, whereas 623 K and 13.7 MPa were needed for heavy neutral feedstock to obtain refined paraffins with a Saybolt color of >+30.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800014u

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 6841–6853

Titre :	Effect of metal dispersion on the liquid-phase hydrodechlorination of 2,4-dichlorophenol over Pd/Al2O3
Type de document :	texte imprimé
Auteurs :	Santiago Gómez-Quero, Auteur ; Fernando Cárdenas-Lizana, Auteur ; Mark A. Kean, Auteur
Année de publication :	2008
Article en page(s) :	p. 6841–6853
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Catalytic hydrodechlorination 2,4-dichlorophenol
Résumé :	The effect of metal particle size on the aqueous-phase (T = 303 K) catalytic hydrodechlorination (HDC) of 2,4-dichlorophenol (2,4-DCP) over Pd/Al2O3 has been investigated. A range of palladium dispersions (8%−67%) was achieved using a H2 thermal treatment over the temperature range of 423 K ≤ T ≤ 1273 K. The catalyst samples have been characterized in terms of transmission electron microscopy (TEM), X-ray diffraction (XRD), surface area/porosity, H2 chemisorption, and point-of-zero-charge measurements. The HDC of 2,4-DCP is predominately a stepwise process, yielding 2-chlorophenol (2-CP) as the partially dechlorinated product, which is further converted to phenol and, ultimately, to cyclohexanone. The temporal dependence of product distribution is recorded and correlated to metal particle size/bulk solution pH changes. Structure sensitivity has been established where smaller palladium particles (≤5 nm) exhibit intrinsically higher specific activities. The HDC of 2,4-DCP has also been investigated under conditions of controlled pH (pHacid = 3 and pHbasic = 13). At pHacid, a greater palladium dispersion delivers greater 2-CP selectivities, as a result of repulsion between chlorophenolic species in solution and a supported Pd−H+ adduct; HDC selectivity at pHbasic is insensitive to palladium particle size. Bulk palladium was inactive under the same reaction conditions, necessitating lower Cl/Pd ratios, but it promoted the removal of both chlorines to a greater extent than that which was observed for Pd/Al2O3. We express, for the first time, HDC performance in terms of solution ecotoxicity and record an 81% decrease in toxicity for reaction at a higher palladium dispersion and pHbasic value. The results establish that catalytic HDC is an effective means of detoxifying chlorophenol-contaminated water.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie0716565

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 6835–6840

Titre :	A novel method for studying multicomponent gas uptake on solid adsorbent with near-infrared process analytical technique
Type de document :	texte imprimé
Auteurs :	Chen-Bo Cai, Auteur ; Qing-Juan Han, Auteur ; Li-Juan Tang, Auteur
Année de publication :	2008
Article en page(s) :	p. 6835–6840
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Orthoxylene/isoamyl alcohol Silica gel Multicomponent gas adsorption
Résumé :	In this paper, we have studied the uptake of orthoxylene/isoamyl alcohol on silica gel as an example to demonstrate a novel methodology for studying multicomponent gas adsorption on solid adsorbent. In the method, the solid adsorbent was filled into a differential adsorption bed, and the bed was inline monitored with near-infrared diffuse reflectance spectroscopy continuously when the adsorption process was taking place. The spectral data recorded during the process were treated with algorithm of locally weighted regression, which constructed a series of partial least-squares models to more accurately predict concentrations of each adsorbate on the adsorbent. These efforts made the method feasible to obtain more thermodynamic and kinetic information about the adsorption process in a more convenient, rapid, economical, as well as straightforward way. With the method, we obtained the isothermal lines of the multicomponent system at 293.15 K, and the instantaneous adsorption rate of each component during the whole adsorption process.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800003z

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 6828–6834

Titre :	Thermal and photocatalytic degradation of poly(methyl methacrylate), poly(butyl methacrylate), and their copolymers
Type de document :	texte imprimé
Auteurs :	Nagu Daraboina, Auteur ; Giridhar Madras, Auteur
Année de publication :	2008
Article en page(s) :	p. 6828–6834
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Poly(methyl methacrylate)--degradation Poly(butyl methacrylate)--degradation o-dichlorobenzene Combustion synthesis TiO2
Résumé :	The photocatalytic degradation of the homopolymers, poly(methyl methacrylate) (PMMA), poly(butyl methacrylate) (PBMA), and their copolymers (PMMABMA) was studied in o-dichlorobenzene in the presence of commercial TiO2 (Degussa P-25) and TiO2 synthesized by combustion synthesis (CSN-TiO2). Gel permeation chromatography was used to determine the evolution of molecular weight distributions with reaction time. The experimental data indicated that the polymers PMMA and PBMA and their copolymers degrade by simultaneous random and chain end scission. A continuous distribution model was developed for the mechanism involved in degradation by both random and chain end scission and used to determine the degradation rate coefficients. The degradation rate coefficients of the polymers in the presence of CSN-TiO2 were higher than the degradation rate coefficients obtained with commercial TiO2 (Degussa P-25). The degradation rate coefficient of copolymers was in between that of the homopolymers and increased linearly with the increase of mol % of PMMA. The degradation of PMMA, PBMA, and their copolymers was also investigated by thermogravimetric analysis. The copolymers exhibited better thermal stability than the homopolymers in contrast to that observed for photocatalytic degradation.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800883n

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 6821–6827

Titre :	Tripolyphosphate made from wet-process phosphoric acid with the use of a rotary kiln
Type de document :	texte imprimé
Auteurs :	Regina Kijkowska, Auteur ; Zygmunt Kowalski, Auteur ; Danuta Pawlowska-Kozinska, Auteur
Année de publication :	2008
Article en page(s) :	p. 6821–6827
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Tripolyphosphate Rotary kiln Wet-process phosphoric acid
Résumé :	The paper presents results on tripolyphosphate (STPP) preparation with the use of a specially constructed laboratory-scale rotary kiln. The kiln enabled agitation of the material calcined at the temperature range 400−430 °C. Wet-process phosphoric acid WPA-1, taken directly from one of the Polish plants, or WPA-2, imported from Finland, was neutralized with Na2CO3 to obtain a phosphate mixture with the molar ratio Na/P = 5/3. To mimic industrial processing with recycling the product, some of the industrial STPP (form-II) was added and the mixture obtained was fed into the rotary kiln through a vibratory feeder. The calcined product was tripolyphosphate in the crystalline form-II, and that did not depend on concentration of the WPA used, or on the amount of the STPP recycled into the kiln. When a similar phosphate mixture WPA + Na2CO3 + STPP-“recycled” was ignited at 400 °C in a stationary chamber oven, the product obtained was also STPP in form-II. In contrast, when a phosphate mixture WPA + Na2CO3 without STPP-“recycled” was calcined, the phase composition of the product obtained depended on the sort of WPA (WPA-1 or WPA-2) and, in the case of WPA-1, on its concentration. From concentrated WPA-2 the STPP formed more readily than from concentrated WPA-1. Lower H3PO4 concentration and recycling of the STPP into the phosphate mixture, before its ignition, creates favorable conditions for the STPP crystallization.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800412q

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 6816–6820

Titre :	Electrochemical degradation of methyl red using BDD and PbO2 anodes
Type de document :	texte imprimé
Auteurs :	Marco Panizza, Auteur ; Giacomo Cerisola, Auteur
Année de publication :	2008
Article en page(s) :	p. 6816–6820
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Lead dioxide Boron-doped diamond anodes Methyl red Electrochemical degradation
Résumé :	The electrocatalytic properties of lead dioxide (PbO2) and boron-doped diamond (BDD) anodes were compared for the electrochemical incineration of methyl red, an azo dye, using an electrolytic flow cell with parallel-plate electrodes. The effects of several operating parameters such as current density, hydrodynamic conditions, and pH on the degradation rate and current efficiency were determined. The experimental data indicate that, on PbO2 and BDD anodes, methyl red oxidation takes place by reaction with hydroxyl radicals electrogenerated from water discharge. The electro-oxidation of methyl red was found to behave as a mass-transfer-controlled process, so that the removal rate and current efficiency were enhanced by high flow rates and independent of the pH in the range of 3.0−7.0. It was also observed that the methyl red decay reaction followed pseudo-first-order kinetics with a rate constant that increased slightly with applied current at the PbO2 anode but was essentially independent of current at the BDD anode. From a comparison of the results, it was found that the BDD anode provided a higher oxidation rate and higher current efficiency; however, the two anodes required almost the same energy consumption for the mineralization of methyl red.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8001292

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 6809–6815

Titre :	Degradation of aqueous p-nitrophenol by ozonation integrated with activated carbon
Type de document :	texte imprimé
Auteurs :	Li Gu, Auteur ; Xingwang Zhang, Auteur ; Lecheng Lei, Auteur
Année de publication :	2008
Article en page(s) :	p. 6809–6815
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Aqueous p-nitrophenol--degradation Granular activated carbon
Résumé :	Degradation of aqueous p-nitrophenol (PNP) by ozonation integrated with granular activated carbon (GAC) was investigated. In the integrated process, organics were removed by the joint effect of oxidation and adsorption, and the removal was considerably enhanced. Operation parameters including pH value and ozone dosage were optimized, and pH was found to be the primary factor in the integrated process. Intermediates in PNP oxidation, including aromatic compounds and low-mass acids, were identified, and possible pathways of PNP degradation were introduced. The reaction mechanism was explored using radical scavenger to suspend the oxidation effect of radicals. The results indicated that the adsorption effect predominated in organics removal at acidic conditions while catalytic oxidation contributed primarily at basic conditions. In addition, the integrated process was successfully applied to treat a high concentrated real wastewater, showing that the integrated process would have great potential in practical application.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie071584h

[article]
in Industrial & engineering chemistry research > Vol. 47 N°18 (Septembre 2008) . - p. 6801–6808

Titre :	Assessment of noncatalytic biodiesel synthesis using supercritical reaction conditions
Type de document :	texte imprimé
Auteurs :	Tanawan Pinnarat, Auteur ; Phillip E. Savage
Année de publication :	2008
Article en page(s) :	p. 6801–6808
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Biodiesel fuel Kinetics
Résumé :	This article reviews the relatively new field of supercritical fluid phase synthesis of biodiesel fuel. We assess the current state of the art and then suggest several directions for new or additional research that would lead to important advances in this field. Biodiesel synthesis at supercritical conditions is technologically feasible and perhaps economically competitive with conventional synthesis routes for low-cost feedstocks such as waste cooking oil. A better understanding of the reaction kinetics (both metal-catalyzed and uncatalyzed) and phase behavior (e.g., location of liquid−liquid−vapor and liquid−vapor regions and critical temperature and pressure as they change during the course of the reaction) is needed. Additionally, there is a need for more detailed analysis of the economics, energy requirements, and environmental impacts of the supercritical process relative to conventional technology.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800542k

Industrial & engineering chemistry research / Paul, Donald R. . Vol. 47 N°18

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