Catalogue en ligne Bibliothèque Ecole Nationale Polytechnique d'Alger

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6987-6990

Titre :	Reaction of tricalcium aluminate with hydrogen chloride under simulated bag filter conditions
Type de document :	texte imprimé
Auteurs :	Kouki Kasuya, Auteur ; Naomi Onodera, Auteur ; Atsushi Iizuka, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6987-6990
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Bag filter
Résumé :	The influence of metals present in fly ash on the dechlorination reaction that occurs at bag filters installed in municipal waste incinerators and melting furnaces has not been investigated previously. Tricalcium aluminate (3CaO·Al2O3, C3A) is considered to be a precursor of complex oxychlorides, and its reaction with HCl was investigated in a gas flow reactor under simulated bag filter conditions (473 K, 1000 ppm HCl, 30 vol% H2O, 5 vol% O2). The molar chlorination ratio of C3A leveled off at about 1 after 24 h. The chlorination reaction rate of C3A was similar to that of calcium hydroxide (Ca(OH)2). C3A chlorination products had a mainly amorphous structure. Elemental mapping images of the surface of chlorinated C3A indicated the likely generation of complex oxychlorides of calcium and aluminum. It is possible that complex oxychlorides are produced at bag filters from complex oxides generated in high-temperature incinerators.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=25900254

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6977–6986

Titre :	Membrane retrofit option for paraffin / olefin separation — a technoeconomic evaluation
Type de document :	texte imprimé
Auteurs :	Anatolie Motelica, Auteur ; Odolphus S. L. Bruinsma, Auteur ; Robert Kreiter, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6977–6986
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Paraffin Olefin
Résumé :	The technical and economic feasibility of a hybrid separation process in which gas separation membranes are combined with conventional distillation are assessed for the separation of ethylene from ethane and of butadiene from a C4-mixture. The potentials for increased energy efficiency and debottlenecking were determined in relation to the required membrane performances. The energy saving potential for the separation of ethylene from ethane is rather low owing to the required very high membrane selectivity. Energy savings can be expected when the membrane selectivity for ethylene is >60. However, the possibility to increase the column capacity in an existing plant by using a membrane is very high. This can become economically attractive if the membrane has a selectivity for ethylene of ≥10. In the case of butadiene separation, the energy savings can be as high as 30% depending on membrane selectivity and process configuration. This high value can be reached when the membrane selectivity for butadiene relative to saturated hydrocarbons equals 15. Again, an increase in the production capacity of butadiene can be achieved in an economic viable fashion.
DEWEY :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie300587u

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6972-6976

Titre :	A note on the analytical solution of cubic equations of state in process simulation
Type de document :	texte imprimé
Auteurs :	Rosendo Monroy-Loperena, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6972-6976
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Thermodynamic properties Equations of state
Résumé :	This work address the problem of round-off errors in the analytical solution (Cardano's Method) of cubic equations of state inside the simulation of chemical processes in the low-temperature region, as it is the case of cryogenic processes involving hydrates calculations. It is proposed as a strategy that can be taken as an iterative refinement of the solution obtained by the analytical method and allows one to take advantage of the calculations fulfilled in the application of the analytical solution (Cardano's Method). Numerical experimentations are presented in order to show the application of the proposed strategy.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=25900252

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6967–6971

Titre :	Use of single - screw extruder for continuous silane cross - linked polyethylene recycling process using supercritical alcohol
Type de document :	texte imprimé
Auteurs :	Toshiharu Goto, Auteur ; Shingo Ashihara, Auteur ; Manabu Kato, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6967–6971
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Twin-screw extruder Supercritical fluids
Résumé :	The development of a continuous process for supercritical fluids is desirable for high-pressure technology. In a previous study, it was revealed that a twin-screw extruder was applicable as the reactor and feeder for industrial supercritical fluid processes (Goto, T.; et al. Ind. Eng. Chem. Res. 2011, 50, 5661–5666). The advantages of twin-screw extruders include their conveying ability and flexibility of design, which make them ideal for research on the applications of extruder. However, twin-screw extruders are expensive because of their complicated gearbox, cylinder shape, screw, etc. Here we report that a single-screw extruder, which is less expensive and simpler than a twin-screw extruder, is also applicable as the reactor and feeder for commercial supercritical fluid processes. Moreover, the equipment for a single-screw extruder is more compact than that of a twin-screw extruder. The results of this study will promote the application of extruders in supercritical fluid engineering research and contribute to the industrialization of a wide range of supercritical fluid techniques.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie202303y

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6958–6966

Titre :	Measurements and correlation of physical solubility of carbon dioxide in (Monoethanolamine + Water) by a modified technique
Type de document :	texte imprimé
Auteurs :	Ying Jiru, Auteur ; Dag A. Eimer, Auteur ; Yi Wenjuan, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6958–6966
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Physical solubility Carbon Dioxide
Résumé :	A modified experimental technique for measuring the physical solubility of CO2 in monoethanolamine (MEA) aqueous solutions using the “N2O analogy” method is proposed in this work. The modified technique employs a scaled spiral glass tube with a small drop of mercury as a eudiometer as an alternative to a three-branch U-tube setup to keep the system pressure constant and measure the volume of a drop of absorbed gas at constant temperature. The results were in good agreement with literature values, suggesting that the technique is feasible and reliable. Compared with the three-branch U-tube setup, the new technique is easy to operate and more sensitive and accurate. The physical solubility of CO2 in aqueous MEA solutions over the full range of concentrations was measured using this modified technique over the temperature range from 298.15 to 323.15 K under a constant ambient pressure. Wang et al.’s model ( Chem. Eng. J. 1992, 48, 31−40) was used to correlate the data, and the results showed that the model is good for predicting the behavior of the (monoethanolamine + water) system.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie3002588

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6948-6957

Titre :	Direct simulations of mixing of liquids with density and viscosity differences
Type de document :	texte imprimé
Auteurs :	J. J. Derksen, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6948-6957
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Viscosity Density Mixing
Résumé :	Simulations of flow and scalar transport in stirred tanks operated in transitional and mildly turbulent regimes (Re = 3000―12000) are presented. The moderate Reynolds numbers allow the flow to be simulated directly, without the use of turbulence closure or subgrid-scale models. The Newtonian liquids that are blended have different densities and/or viscosities, and the emphasis is on how these differences affect mixing times. The density difference is characterized by a Richardson number (Ri) that varies in the range of 0―0.5. The kinematic viscosity ratio is between 1 and 4. The results show that mixing times increase steeply with increasing Ri and that changing the tank layout can partly mitigate this effect. The viscosity ratio has a much weaker influence on the mixing time.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=25900249

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp 6939–6947

Titre :	Analysis on Laminar chaotic mixing based on configuration of streak lobes in an impeller - agitated vessel
Type de document :	texte imprimé
Auteurs :	Shunsuke Hashimoto, Auteur ; Ryota Osaka, Auteur ; Makiko Kawamata, Auteur
Année de publication :	2012
Article en page(s) :	pp 6939–6947
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	laminar chaotic
Résumé :	In the case of laminar chaotic mixing in a stirred tank, our previous study theoretically revealed that the streakline originating from the tip of the impeller provides the formation of a mixing pattern and its outline comes close to the configuration of the streakline with respect to time. In the present study, the laminar chaotic mixing in a 3-D stirred tank was investigated experimentally by use of a new index, “streak lobes”, which were equivalent to the region surrounded by the streakline. The streak lobes were created by the minute perturbation wave (traveling wave) that is generated by the rotation of the impeller blade in a stirred tank. The amplitude and frequency of their traveling waves were dominant for the size (width and area) and/or number of streak lobes. The experimental results demonstrated that the large area of streak lobes in the 3-D velocity field resulted in good chaotic mixing, even if the number of streak lobes is small. In addition, the fluid exchange between top and bottom regions in the stirred tank occurred rapidly in the case where the streak lobes could come and go between two regions. It was suggested that the streak lobes can play an important role as an index whether or not good chaotic mixing occurs in the stirred tank. The present study proposed that the control of the size and/or number of streak lobes adjusting the amplitude and frequency of the traveling wave caused by impeller rotation resulted in a shortcut to enhance laminar chaotic mixing.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie203036n

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6933-693

Titre :	Correlation of solubilities of hydrophilic pharmaceuticals versus dielectric constants of binary solvents
Type de document :	texte imprimé
Auteurs :	Xinwei Zhang, Auteur ; Qiuxiang Yin, Auteur ; Penglei Cui, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6933-693
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Solubility Correlation analysis Correlation
Résumé :	In this paper, the polarity of binary solvents was studied by the sum law of cube roots of the dielectric constant During the antisolvent crystallization process, the composition of the binary solvents and their dielectric constants changed simultaneously. These results demonstrated that variation of the solubility is dependent on the polarity of the binary solvents. On the basis of experiments, a new model was put forward to quantitatively describe the relationship between the solubility of hydrophilic pharmaceuticals and the dielectric constants of the binary solvents. Furthermore, this model was tested and verified by solubility data of other pharmaceuticals published in the literature with high accuracy.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=25900247

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6926-6932

Titre :	Development of a hybrid model for industrial ethylene oxide reactor
Type de document :	texte imprimé
Auteurs :	Na Luo, Auteur ; Wenli Du, Auteur ; Zhencheng Ye, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6926-6932
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Reactor Modeling
Résumé :	A hybrid modeling approach for an ethylene oxidation reactor with silver catalyst is proposed. Under the form of mechanistic model, support vector regression is used to construct the catalyst deactivation model with the operating data coming from real plant. Prior knowledge is extracted to enhance the generalization of the deactivation model. With the hybrid model, the prediction error is less than 5% for the prediction of industrial reactor. The approach is shown to predict the production more accurately and have more reliable extrapolation.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=25900246

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6916-6925

Titre :	Experiments and modeling of volumetric properties and phase behavior for condensate gas under ultra - high - pressure conditions
Type de document :	texte imprimé
Auteurs :	Chang-Yu Sun, Auteur ; Huang Liu, Auteur ; Ke-Le Yan, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6916-6925
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Modeling
Résumé :	Four reservoir samples under ultra-high-pressure and high-temperature conditions were collected from condensate gas fields in China. Constant-composition expansion tests were performed to determine the phase behavior and volumetric properties of reservoir fluid using an ultra-high-pressure fluid PVT test system. The compressibility factor and dew-point pressure were obtained at four temperatures for four samples. The range of pressure was from 22.03 to 118.89 MPa. For the samples studied, the experimental results showed that the dew-point pressure decreased with increasing temperature and the compressibility factors increased with increasing pressure but decreased with increasing temperature at a given high reduced pressure. A thermodynamic model based on an equation of state was developed to describe the volumetric properties and phase behavior of the condensate gas under ultra-high-pressure conditions. The calculated results are in good accordance with the experimental data, which is important for the development of condensate gas reservoirs in ultra-high-pressure environments.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=25900245

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6907-6915

Titre :	Evaluation of a primary amine - functionalized ion - exchange resin for CO2 capture
Type de document :	texte imprimé
Auteurs :	W. Richard Alesi, Auteur ; John R. Kitchin, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6907-6915
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Carbon dioxide Ion exchange resin
Résumé :	A primary amine-functionalized polymeric ion-exchange resin (Lewatit VP OC 1065, Lanxess) was evaluated for use in CO2 capture applications. The polymeric resin was characterized by SEM, DRIFTS-IR, N2 adsorption isotherms, and packed bed sorption measurements to determine some of the characteristic properties of the resin. Capture capacities ranging from 1.85 to 1.15 mol CO2/kg sorbent were obtained in a packed bed reactor exposed to 10 vol % CO2 in N2 at adsorption temperatures ranging from 30 to 70 °C. The capture capacity of the resin was stable over 18 adsorption/regeneration cycles. The resin was evaluated through thermogravimetric analysis to have a low moisture adsorption (1.5 mol H2O/kg sorbent). It is possible to completely regenerate the resin under 1 atm of CO2 at 200 °C.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=25900244

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6895-6906

Titre :	Amine - functionalized MIL - 53 metal – organic framework in polyimide mixed matrix membranes for CO2 / CH4 separation
Type de document :	texte imprimé
Auteurs :	Xiao Yuan Chen, Auteur ; Hoang Vinh-Thang, Auteur ; Denis Rodrigue, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6895-6906
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Carbon dioxide
Résumé :	Flexible crystalline metal-organic framework (MOF) of nanosize particles (Al-MIL-53) and 6FDA-ODA polyimides were used to produce mixed matrix membranes (MMM). These MMM display excellent CO2/CH4 separation properties even without any compatibilization (amine grafting). The ideal selectivity and separation factor were found to increase with increasing MOF loading. Furthermore, these materials have an improved CO2/CH4 separation factor with increasing pressure, in contrast to traditional polymer membranes.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=25900243

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6887-6894

Titre :	Thermal, oxidative, and CO2 - induced degradation of supported polyethylenimine adsorbents
Type de document :	texte imprimé
Auteurs :	Aliakbar Heydari-Gorji, Auteur ; Abdelhamid Sayari, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6887-6894
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Carbon dioxide Oxidation
Résumé :	This work examines the stability of polyethylenimine(PEI)-impregnated mesoporous silica for CO2 removal over a wide range of conditions. The support used was a SBA-15 silica with platelet morphology and short pore channels (SBA-15PL). The effect of long-term exposure to different gaseous streams, including carbon-free air (CFair), simulated flue gas (SFG), and different CO2/O2/N2 mixtures on the carbon dioxide adsorption capacity was investigated. Extensive CO2 adsorption― desorption cycling using dry and humid streams at different adsorption and regeneration temperatures was also carried out Based on adsorption data, as well as diffuse reflectance infrared Fourier transform (DRIFT) and 13C CP MAS NMR measurements, it was found that PEI-modified adsorbents exhibit (i) high thermal stability at moderate temperatures, (ii) highly stable CO2 uptake in the presence of moisture, (iii) extensive degradation in the presence of dry CO2, particularly at high temperature, (iv) fast degradation upon exposure to CFair even at moderate temperatures, (v) excellent stability in the presence of humidified gases containing both CO2 and O2,
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=25900242

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6877–6886

Titre :	Antimony(III) adsorption from aqueous solution using raw perlite and Mn - modified perlite : Equilibrium, thermodynamic, and kinetic studies
Type de document :	texte imprimé
Auteurs :	Ahmet Sari, Auteur ; Gungor Sahinoglu, Auteur ; Mustafa Tuzen, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6877–6886
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Adsorption Aqueous Solution Thermodynamic Kinetic
Résumé :	In this study, the adsorption potential of expanded perlite (EP) and manganese oxides-modified EP (Mn-MEP) for the removal of Sb(III) from aqueous solution were investigated. The influence of solution pH, adsorbent concentration, contact time and temperature on the Sb(III) adsorption were studied using the batch method. Modification of the surface of EP with 0.18 g of manganese oxide per gram EP showed an increase of 1.6-fold in its surface area. The raw EP and Mn-MEP samples with Sb(III) ions were characterized before and after the adsorption process using FT-IR and SEM analysis techniques. The monolayer adsorption capacity of EP and Mn-MEP for Sb(III) was found to be 54.4 and 76.5 mg g–1 at pH 4, respectively. The mean adsorption energy (6.3 kJ mol–1) calculated from the Dubinin–Radushkevich model indicated that the adsorption of Sb(III) onto Mn-MEP was physically carried out. After 10 times of adsorption/desorption cycles, the reusability of Mn-MEP decreased as slightly as 5% for adsorption and 7% for desorption. The calculated thermodynamic parameters (ΔGo, ΔHo, and ΔSo) showed that the adsorption was feasible, spontaneous, and exothermic. The kinetic parameters revealed that the adsorption of Sb(III) onto Mn-MEP followed well the pseudo-second-order kinetic model. In addition, from a practical viewpoint, Mn-MEP is a promising adsorbent for the removal of Sb(III) from aqueous solutions since it has large surface area, high adsorption capacity, easy availability, low-cost, and good reusability performance.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie300243n

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6869–6876

Titre :	Adsorptive removal of saturated and unsaturated fatty acids using Ion - exchange resins
Type de document :	texte imprimé
Auteurs :	Ganesh L. Maddikeri, Auteur ; Aniruddha B. Pandit, Auteur ; Parag R. Gogate, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6869–6876
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Acids Ion exchange
Résumé :	One of the pretreatment approaches for decreasing the initial acid content of waste vegetable oil or nonedible oils with high initial free fatty acid content, with an objective of obtaining a suitable starting raw material for the production of biodiesel, is the adsorption of the free acids using ion-exchange resins. The present work deals with investigation of adsorption characteristics of saturated (stearic) and unsaturated (oleic) fatty acids on different ion exchange resins (polymeric strong (Indion 810) and weak (Indion 850 and Indion 860) anion exchange resins). The ion exchange resins contain tertiary or quaternary amino functional groups on the styrene-divinyl benzene copolymer matrix which can facilitate the adsorption of acids. Kinetic adsorption studies have been carried out initially to determine the contact time required to reach the adsorption equilibrium between fatty acid adsorbed on the resin and remaining fatty acid present in the oil. Equilibrium adsorption studies have been carried out at different temperatures viz. 293, 303, and 313 K. It has been observed that adsorption of saturated and unsaturated fatty acids increased with its concentration in the liquid at constant temperature and decreased with an increase in the temperature at constant concentration. Also, the adsorption equilibrium data have been found to be well described by the Freundlich type isotherm. The negative values of ΔG and ΔH showed that the adsorption of both saturated and unsaturated acids on the ion exchange resins was spontaneous and also exothermic.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie3000562

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6862-6868

Titre :	Kinetics and mechanism of tartrazine adsorption onto chitin and chitosan
Type de document :	texte imprimé
Auteurs :	Guilherme L. Dotto, Auteur ; Mery L. G. Vieira, Auteur ; Luiz A. A. Pinto, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6862-6868
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Adsorption Kinetics
Résumé :	In this work the kinetics and mechanisms of tartrazine adsorption onto chitin and chitosan were studied at different pH values (3, 5, 7, 9 and 11). Five models were employed to elucidate the adsorption kinetics. The adsorption mechanisms were verified by use of models based on mass transfer and elemental analysis. The adsorption capacity was increased with pH decrease, reaching maximum values at pH 3. The maximum values were 30 mg·g―1 and 350 mg·g―1 for chitin and chitosan, respectively. For both adsorbents a fast kinetic was observed, and the Avrami model was the more adequate to fitting the experimental data. Tartrazine adsorption onto chitin occurred only by film diffusion. In the chitosan case, adsorption occurred by film and intraparticle diffusion, however, intraparticle diffusion was the rate-limiting step. At pH 3, tartrazine adsorption onto chitin and chitosan occurred by chemical interactions.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=25900239

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6847-6861

Titre :	Dynamics of flocculation of lignocellulosic hydrolyzates by polymers
Type de document :	texte imprimé
Auteurs :	L. Rakesh Yasarla, Auteur ; Bandaru V. Ramarao, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6847-6861
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Flocculation
Résumé :	Pretreatment of lignocellulosic materials involves the solubilization of heniicelluloses, small portions of the lignin, and such components. The hemicellulose solutions are hydrolyzed for downstream fermentation into biofuels or biomaterials. Hydrolyzates produced by pretreatment contain significant colloidal material that is anionically charged. Many of the compounds that are present in the hydrolyzates are inhibitory to fermentation and interfere with downstream separations. The flocculation of this colloidal material makes separations easier by sedimentation and can reduce the fouling tendencies of membranes. It can also reduce the toxicity of the hydrolyzates to fermentation micro-organisms. We studied the dynamics of flocculation of lignocellulosic hydrolyzates with a variety of flocculating agents: electrolytes (alum) and polymers (PEI, pDADMAC, CPAM). It was found that trivalent cations were the most effective suspension destabilizers among the electrolytes, while the cationic polymers could cause flocculation and also redispersion depending on their dosage levels. Flocculation reduced the hydrolyzates' turbidity from > 10000 to under 20. With PEI and pDADMAC, flocculation occurred rapidly when the zeta potential of the colloid was close to zero showing that charge neutralization is the significant destabilizing mechanism. At higher dosages, redispersion occurred indicating that patching is also important in flocculation. Flocculation by PEI was sensitive to pH (from hydrolyzate pH of 3 to 8) with increased dosage necessary at higher pH values. The cationicity of PEI is reduced at higher pH which results in loss of its effectiveness. On the other hand, the zeta potential was largely unaffected with CPAM dosage indicating the dominance of bridging flocculation. Floc sizes ranged up to 3 mm, depending on flocculant dose and pH.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=25900238

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6841–6846

Titre :	Optimization, kinetics, and thermodynamics in the extraction process of puerarin by decompressing inner ebullition
Type de document :	texte imprimé
Auteurs :	Xiaoguang Chen, Auteur ; Tengyou Wei, Auteur ; Mengwei Peng, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6841–6846
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Kinetics Thermodynamics
Résumé :	Decompressing inner ebullition (DIE) is a novel method and it can achieve a rapid extraction at lower temperature for active constituents of medical plants. In this work, DIE was employed to extract puerarin from puerarin lobata (Willd.) Ohwi (PLO). The extraction conditions were investigated according single factor analysis. Experiment results showed that the extraction yield of puerarin reached a maximum value when the ethanol mass concentration in the aqueous solution immersing the PLO was 60%, the amount of ethanol solution for premaceration and of water for extraction were 1.6 and 10 mL·g–1 of PLO, respectively, the operation gauge pressure was −0.084 MPa, and the extraction temperature was 50 °C. Under the optimal conditions, the extraction kinetics of DIE was studied. The mass transfer coefficient of DIE ranged between 0.09 and 0.13 s–1, which is 183 times greater than that of ultrasonic assistant extraction under the same conditions, and its extraction activation energy ΔE is 10.86 kJ·mol–1. Also, the thermodynamics properties in the extraction process of DIE at 50 °C were also calculated, the enthalpy change ΔH is 58.76 kJ·mol–1, the entropy change ΔS is 224.50 J·mol–1·K–1, and Gibbs free energy ΔG is −13.73 kJ·mol–1, respectively. The extraction of DIE belongs to a spontaneous process with endothermic and entropy increasing.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie2020153

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6823-6840

Titre :	An efficient multiperiod MINLP model for optimal planning of offshore oil and gas field infrastructure
Type de document :	texte imprimé
Auteurs :	Vijay Gupta, Auteur ; Ignacio E. Grossmann, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6823-6840
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Mathematical programming Planning Modeling Mixed integer programming Non linear programming
Résumé :	In this paper, we present an efficient strategic/tactical planning model for offshore oilfield development problem that is fairly generic and can be extended to include other complexities. The proposed multiperiod nonconvex MINLP (mixed integer nonlinear programming) model for multifield site includes three components (oil, water, and gas) explicitly in the formulation using higher order polynomials, avoiding bilinear and other nonlinear terms. With the objective of maximizing total NPV for long-term planning horizon, the model involves decisions related to FPSO (floating production, storage, and offloading) installation and expansion, field―FPSO connections, well drilling, and production rates in each time period. The model can be solved effectively with DICOPT for realistic instances and gives good quality solutions. Furthermore, it can be reformulated into an MILP after piecewise linearization and exact linearization techniques that can be solved globally in an efficient way. Solutions of realistic instances involving 10 fields, 3 FPSOs, 84 wells, and 20 years planning horizon are reported, as well as comparisons between the computational performance of the proposed MINLP and MILP formulations.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=25900236

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6811–6822

Titre :	Probabilistic PCA - based spatiotemporal multimodeling for nonlinear distributed parameter processes
Type de document :	texte imprimé
Auteurs :	Chenkun Qi, Auteur ; Han-Xiong, Li, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6811–6822
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Probabilistic
Résumé :	Many industrial processes are nonlinear distributed parameter systems (DPSs). Data-based spatiotemporal modeling is required for analysis and control when the first-principles model is unknown. Because a DPS is infinite-dimensional and time–space coupled, a low-order model is necessary for prediction and control in practice. For low-order modeling, traditional principal component analysis (PCA) is often used for dimension reduction and time–space separation. However, it is a linear method and leads to only one set of fixed spatial basis functions. Therefore, it might not be always effective for nonlinear systems. In this study, a spatiotemporal multimodeling approach is proposed for unknown nonlinear DPSs. First, multimodel decomposition is performed, where probabilistic PCA (PPCA) is used to obtain multiple sets of spatial basis functions from the experimental data by maximizing a likelihood function. Using these multiple sets of PCA spatial bases for time–space separation, the high-dimensionality spatiotemporal data can be reduced to multiple sets of low-dimensionality temporal series. Then, multiple low-order neural models can be easily established to model these local dynamics. Finally, the original spatiotemporal dynamics can be reconstructed by multimodel synthesis. Because the proposed spatiotemporal modeling approach involves a multimodeling mechanism, it can achieve better performance than the traditional PCA-based single-modeling for nonlinear DPSs, which is demonstrated by numerical simulations.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie202613t

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6798-6810

Titre :	Integration design of heat exchanger networks into membrane distillation systems to save energy
Type de document :	texte imprimé
Auteurs :	Yanyue Lu, Auteur ; Junghui Chen, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6798-6810
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Membrane separation Membrane distillation Heat exchanger Meshed network Design
Résumé :	Membrane distillation requires a lower operation temperature than other separation processes. It is also able to use low-grade thermal energy. In this study, an integrated design method that utilizes a membrane distillation (MD) system to produce pure water is presented. This method is the integration of the heat exchanger network (HEN) into the MD system, and it uses the waste heat from HEN as the energy source of the MD process so as to greatly reduce the water cost. In this proposed method, a multistage MD system is designed to generate the optimal system structure and operating conditions. Then the output and input MD streams are merged into the existing HEN so that the energy cost of pure water can be determined by redesigning the HEN with the trans-shipment models. The efficiency of the proposed method is demonstrated through an industrial case.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=25900234

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6789-6797

Titre :	Sensor network design for optimal process operation based on data reconciliation
Type de document :	texte imprimé
Auteurs :	M. Nabil, Auteur ; Sridharakumar Narasimhan, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6789-6797
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Data reconciliation Design
Résumé :	The fundamental problem in optimal sensor network design is choosing a set of important or strategic process variables to be measured. An optimization formulation for sensor network design that relates process economics and data reconciliation is proposed. To address this, an economic quantity is defined to quantify the loss of operational profit caused due to measurement uncertainty. The resulting analytical expression that quantifies the loss is shown to be the sum of weighted error variances of the reconciled estimates obtained from reconciliation. The final formulation is a mixed integer cone program that can be solved to obtain a globally optimal sensor network The effect of the process economics, capital cost, and marginal utility of additional sensors is illustrated using case studies.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=25900233

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6760-6768

Titre :	A comparative theoretical and computational study on robust counterpart optimization : II. Probabilistic guarantees on constraint satisfaction
Type de document :	texte imprimé
Auteurs :	Zukui Li, Auteur ; Qiuhua Tang, Auteur ; Christodoulos A. Floudas, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6760-6768
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Optimization
Résumé :	Probabilislic guarantees on constraint satisfaction for robust counterpart optimization are studied in this paper. The robust counterpart optimization formulations studied are derived from box, ellipsoidal, polyhedrai, "interval+ellipsoidal", and "interval+polyhedral" uncertainty sets (Li, Z.; Ding, R.; Floudas, CA A Comparative Theoretical and Computational Study on Robust Counterpart Optimization: L Robust Linear and Robust Mixed Integer Linear Optimization. Ind. Eng. Chem. Res. 2011, 50, 10567). For those robust counterpart optimization formulations, their corresponding probability bounds on constraint satisfaction are derived for different types of uncertainty characteristic (i.e., bounded or unbounded uncertainty, with or without detailed probability distribution information). The findings of this work extend the results in the literature and provide greater flexibility for robust optimization practitioners in choosing tighter probability bounds so as to find less conservative robust solutions. Extensive numerical studies are performed to compare the tightness of the different probability bounds and the conservatism of different robust counterpart optimization formulations. Guiding rules for the selection of robust counterpart optimization models and for the determination of the size of the uncertainty set are discussed. Applications in production planning and process scheduling problems are presented.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=25900232

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6760-6768

Titre :	Bi2O2CO3 / BiOI photocatalysts with heterojunctions highly efficient for visible - light treatment of dye - containing wastewater
Type de document :	texte imprimé
Auteurs :	Lang Chen, Auteur ; Shuang-Feng Yin, Auteur ; Sheng-Lian Luo, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6760-6768
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Waste water Dyes Visible radiation Photocatalysis Catalyst
Résumé :	Bi2O2CO3/BiOI composites were fabricated at room temperature for the first time by a facile method. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectra (UV―vis DRS), and nitrogen adsorption-desorption techniques were employed to characterize the physiochemical properties of the composites. The photocatalytic activities of Bi2O2CO3, BiOI, and Bi2O2CO3/BiOI were evaluated through the photocleaning of wastewater which contained rhodamine-B, methylene blue, crystal violet, or a mixture of them under visible-light irradiation (λ ≥ 420 nm). The photocatalytic activity of Bi2O2CO3/BiOI is much higher than that of its components. Moreover, the composite shows good photostability and recyclability. The excellent catalytic efficiency of the Bi2O2CO3/BiOI composite is deduced closely related to Bi2O2CO3/BiOI heterojunctions whose presence is generally regarded to be a favorable factor for the separation of photogenerated electrons and holes. Moreover, ·OH was found to be the main active species for the photocatalytic interactions. The catalyst shows potential application in the treatment of dye-containing wastewater.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=25900231

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6753-6759

Titre :	Highly transparent and multifunctional polymer nanohybrid film with superhigh ZnO content synthesized by a bulk polymerization method
Type de document :	texte imprimé
Auteurs :	Hai-Tao Liu, Auteur ; Xiao-Fei Zeng, Auteur ; Hong Zhao, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6753-6759
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Polymerization
Résumé :	Highly transparent and multifunctional ZnO/poly(n-butyl methacrylate) (ZnO/PBMA) nanohybrid films with superhigh contents of ZnO nanoparticles (NPs) were synthesized by a bulk polymerization method. The structure; morphology; and optical, mechanical, and thermal properties of the obtained nanohybrid films were studied. ZnO NPs were dispersed uniformly and retained their original size (4―6 nm) in the PBMA matrix without any aggregation. The ZnO/PBMA nanohybrid films allowed more than 90% of visible light at 550 nm to pass and maintained almost the same high transparency as pure PBMA film even when the ZnO NP content was as high as 60 wt %. The nanohybrid films embedded with ZnO NPs exhibited significantly enhanced multifunctional performance, including excellent UV-shielding properties, good thermal stability, high surface hardness, and desired flexibility. In particular, the coefficient of thermal expansion (CTE) of the nanohybrid films dearly decreased to 193 from 325 ppm/K for pure PBMA below the glass transition temperature (Tg) and strikingly decreased from 5378 to 1373 ppm/K after the glass transition. The ZnO/polymer nanohybrids synthesized in this work are promising for the fabrication of optical devices with high transparency, such as flexible displays, optical filters, and flexible solar cells.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=25900230

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6745-6752

Titre :	Pilot plant scale synthesis of CNS : Influence of the operating conditions
Type de document :	texte imprimé
Auteurs :	Vicente Jiménez, Auteur ; Alfredo Muñoz, Auteur ; Paula Sánchez, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6745-6752
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Operating conditions Pilot plant scale
Résumé :	The present work was an in-depth study related to synthesis of carbon nanospheres (CNSs) at different scales (lab and pilot) with the end goal to economize the production of these materials on a large scale. Synthesis of large amounts of CNSs relies on the careful control of the operating conditions such as space velocity (helium flow rate), hydsocarbon (benzene) content in feed stream, and synthesis time. The alteration of these variables caused important changes in both the yield and properties of the obtained materials. In general, characterization results of the synthesized CNSs demonstrated that they showed low BET surface area and pore volume values typical of spherical geometrical bodies, good thermal stability, and good crystallinity. Normally, CNSs are presented as conglomerates as consequence of the accretion via the carbon atoms at the edge of the "curling" graphitic flakes. Finally, results demonstrated a successful scale up, obtaining a CNSs yield at pilot scale considerably superior (factor of 3.9) to that obtained at laboratory scale.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=25900229

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6731-6744

Titre :	Zeta potential and slip coefficient measurements of hydrophobic polymer surfaces exploiting a microchannel
Type de document :	texte imprimé
Auteurs :	Hung Mok Park, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6731-6744
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Electrokinetic potential
Résumé :	The surface charge and wettability of polymer surfaces are important properties that affect various physicochemical properties such as adhesion, hydrophilicity, and swelling. The zeta potential gives information of the ions distribution at the electric double layer (EDL), and the Navier slip coefficient is also an important indicator of the wettability of surfaces. In the present investigation, a technique is devised to measure the zeta potential and the slip coefficient of polymer surfaces nondestructively exploiting electrokinetic flows in a microchannel, which is formed by combining a probe cell and a macroscopic polymer surface under consideration. By measuring zeta potential and volumetric flow rate of electroosmotic flow at various bulk ionic concentration, one can estimate the zeta potential and slip coefficient accurately even under significant experimental errors in the measurement of streaming potential and volumetric flow rate. The method devised in the present investigation may be employed to estimate zeta potential and slip coefficient of various polymeric surfaces, which are important characterizing various physicochemical properties of polymers.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=25900228

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6722-6730

Titre :	Solvent free generation of open and skinless foam in poly (l - lactic acid) / poly (d,l - lactic acid) blends using carbon dioxide
Type de document :	texte imprimé
Auteurs :	Xia Liao, Auteur ; Arghavan V. Nawaby, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6722-6730
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Carbon dioxide Foam
Résumé :	Foams generated via carbon dioxide (CO2) processing typically exhibit a solid skin layer on the exterior surface and a closed-pore structure with limited interconnectivity in the core section thus limiting its application for biomedical intent. By controlling the properties of poly(L-lactic acid)/poly(D,L-lactic acid) (PLLA/PDLLA) blends and using CO2 with specific processing parameters, skinless foams with interconnected porous structure were prepared in this work using only CO2 as a physical foaming agent, which overcome the necessity to use organic solvents and solid porogens. The crystallization behaviors and sorption kinetics of PLLA and its blends were studied. Addition of PDLLA reduces the crystallinity of PLLA/PDLLA blends while treated with CO2 as compared to neat PLLA. The solubility and diffusion coefficients of CO2 in PLLA and its blends were found to be similar. Furthermore, the effect of PLLA/PDLLA blend ratio and CO2 treatment conditions on the foam morphologies was investigated. Through fine parameter control, well interconnected pore structures with a porous surface were generated. Results indicated that by controlling the physical properties of samples combined with optimizing CO2 foaming process, it is indeed possible to create biodegradable interconnected porous structures for potential biomedical applications.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=25900227

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6714-6721

Titre :	Corrosion behavior of carbon steel at typical positions of an amine - based CO2 capture pilot plant
Type de document :	texte imprimé
Auteurs :	Jubao Gao, Auteur ; Shujuan Wang, Auteur ; Chenchen Sun, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6714-6721
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Pilot plant Carbon dioxide Carbon steel Corrosion
Résumé :	Corrosion tests of carbon steel at six typical positions in a CO2 capture pilot plant using amine-based solvent were conducted with simulated flue gas ( 12 vol % CO2, 18 vol % O2 and 214 ppm SO2). A weight-loss method was used to determine the corrosion rates for about 400 h of experiment. Scanning electron microscopy and energy dispersive X-ray spectroscopy were used to analyze the morphology and compositions of the coupon surface and cross section. The corrosion products on the sample's surface and cross section were analyzed with X-ray diffraction and Raman spectroscopy, respectively. Experimental and theoretical analyses show that the higher corrosion rates among these positions were present at the bottom of the absorber and rich liquid outlet of the rich-lean heat exchanger. The double-layer structure of the corrosion products with different colors was obviously observed on the cross sectional surface of the coupons at the absorber bottom and the stripper inlet. The corrosion products in the inner layer are mainly composed of hematite (a-Fe2O3) and magnetite (Fe3O4) with traces of goethite (a-FeOOH), while the outer layer mainly consists of siderite (FeCO3). The inner corrosion products, including a-Fe2O3, Fe3O4, and a-FeOOH, may come from the decomposition of FeCO3 in the amine-H2O―CO2―O2―SO2 system. An addition of SO2 yields large amounts of hydrogen ion and dissolved oxygen which may induce a higher corrosion rate.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=25900226

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6705–6713

Titre :	Rheology of carbon nanotubes – filled poly(vinylidene fluoride) composites
Type de document :	texte imprimé
Auteurs :	Defeng Wu, Auteur ; Jianghong Wang, Auteur ; Ming Zhang, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6705–6713
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Rheology Carbon nanotubes
Résumé :	The carbon nanotubes (CNTs)–filled poly(vinylidene fluoride) (PVDF) composites (PCTs) were prepared by melt compounding for rheological study. The steady and oscillatory flow behaviors were then explored. The results show that the presence of CNTs enhances the pseudoplastic flow accompanied by the increased flow activation energy. However, the linear flow region is not sensitive to the temperature whether driven by shear rate or by strain. During oscillatory shear flow, the solid-like response is attributed to the percolation of CNTs, but the formation of a percolated CNT network is temperature-dependent, and the percolation threshold values reduce with an increase of temperature. The two-phase viscoelastic model was then used to further describe the linear responses of composites, aiming at relating hierarchical structures of the CNTs to flow behaviors of the composites.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie2024454

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6697–6704

Titre :	Effect of rubber – filler interaction on transport of aromatic liquids through high density polyethylene / ethylene propylene diene terpolymer rubber blends
Type de document :	texte imprimé
Auteurs :	Anil Kumar P. V., Auteur ; K. T. Varughese, Auteur ; Sabu Thomas, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6697–6704
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	High density Transport process Filler
Résumé :	The sorption and transport of four aromatic hydrocarbons through dynamically vulcanized high density polyethylene/ethylene propylene diene terpolymer rubber blends filled with carbon black and that filled with silica at the same loading have been investigated in the temperature range of 28–58 °C by an equilibrium swelling technique . Blends loaded with high abrasion furnace (HAF) black and those with silica of same loading have been used. The silica-incorporated blends sorbed a higher amount of aromatic solvents compared with the HAF filled blends. This has been explained in terms of the differences in the interaction between the filler particles and the blend components. The swelling coefficient, diffusion coefficient, and molar mass between cross-links have been computed to complement the experimental observations.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=25900224

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6686–6696

Titre :	Modeling studies on lean NOx reduction by a sequence of LNT – SCR bricks
Type de document :	texte imprimé
Auteurs :	Arun S. Kota, Auteur ; Dan Luss, Auteur ; Vemuri Balakotaiah, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6686–6696
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	NOx Selective catalytic reduction
Résumé :	Several experimental studies have been conducted to determine the NOx reduction by a series of LNT (lean NOx trap) and SCR (selective catalytic reduction) catalytic bricks. An important goal is to minimize the required precious metal loading in the LNT while keeping the NOx emission below a specified level. We present a mathematical model of this system using hydrogen as the reductant. Simulations are used to determine the influence of the architecture of the LNT–SCR bricks, nonuniform precious metal loading in the LNT bricks, and the cycle time at temperatures in the range of 200–350 °C. The simulations lead to the following observations: (a) Low temperature reduction is the limiting step in the optimization of precious group metal (PGM) loading in LNT. (b) The NOx conversion increases as the number of the sequential bricks (with total length fixed) increase and reaches an asymptotic limit. From a practical point of view, there is little incentive in using more than two sequential pairs. (c) Nonuniform precious metal loading of the LNT bricks results in only a minor improvement in the deNOx performance. (d) The cycle time has a significant impact on the NOx conversion. In the simulated example, the NOx conversion at low temperatures is increased by about 15–20% by reducing the cycle time by a factor of 2. (e) Even at low temperature operation, diffusional limitations in the washcoat are most likely to be important in the LNT but not in the SCR operation. The NOx conversion and ammonia selectivity are reduced when washcoat diffusion is dominant in the LNT.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie300190c

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6680-6685

Titre :	Thermal and kinetic analysis of the process of thermochemical decomposition of phosphogypsum with CO and additives
Type de document :	texte imprimé
Auteurs :	Liping Ma, Auteur ; Yalei Du, Auteur ; Xuekui Niu, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6680-6685
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Additive Kinetics
Résumé :	Phosphogypsum (PG) is a waste byproduct from the processing of phosphate rock by the "wet add method" of fertilizer production. One of the main methods for reusing PG is to decompose and recycle Ca and sulfur contained in it. However, the decomposition reaction process is very complex because of its complicated contents, and very high temperature is needed for the reaction. In this paper, to decrease the reaction temperature, CO as a main reducer and some additives were added in the decomposition process. Results show that the decomposition temperature will decrease from 1000 to 809 °C with pure CO. When CaCl2 is used as an additive, the decomposition temperature can decrease to 790 °C, and at the same time the reaction rate will be increased, the main product being CaS at this condition. The thermal and kinetic action of this process has also been discussed.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=25900222

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6672–6679

Titre :	Evaluating the effects of precious metal distribution along a monolith - supported catalyst for CO oxidation
Type de document :	texte imprimé
Auteurs :	Suad M. Al Adwani, Auteur ; Joao Soares, Auteur ; William S. Epling, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6672–6679
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Metal Catalyst Oxidation
Résumé :	Zone-coated diesel oxidation catalysts (DOCs) can be used to obtain overall improved performance in oxidation reaction extents. However, why this occurs and under what conditions an impact is expected are unknown. In order to demonstrate why these catalysts work better than their standard counterparts and how significant the improved performance is, the CO oxidation performance over a series of Pt–Pd/Al2O3 catalysts, each with a different distribution of precious metal down the length, while maintaining equivalent totals of precious metal, was modeled. Simulations with different flow rates, ramp rates, steady-state temperatures at the end of the ramp rate, different total precious metal loadings, and CO inlet values were compared. In terms of light off, at conversions less than 50%, the most significant differences were noted when the temperature was ramped to just at the CO oxidation light-off point, with catalysts containing more precious metal at the downstream portions leading to better light-off conversion performance. However, in terms of cumulative emissions over a long period of time, a “front-loaded” design proved best. These results are readily explained by decreased CO poisoning and the propagation of the exothermic heat from the front to the rear of the catalyst. Also, although the trends were the same, regardless of change in the parameter, the impact of different distributions was more apparent under conditions where a catalyst would be challenged, i.e., at low temperature ramp rates, higher CO inlet concentrations, and lower amounts of total catalyst used. At higher ramp rates, the input heat from the entering gas stream played an increasingly important role, relative to conduction associated with the exotherm, dampening the effects of the catalyst distribution. Therefore, although catalysts that are zone-coated with precious metals, or any active sites, could prove better in terms of performance than homogeneously distributed active site catalysts, this improvement is only significant under certain reaction conditions and thus application of these catalysts may not be appropriate for all drive cycles or applications.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie202969u

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6666-6671

Titre :	Esterification of acrylic acid with different alcohols catalyzed by zirconia supported tungstophosphoric acid
Type de document :	texte imprimé
Auteurs :	Emine Sert, Auteur ; Ferhan Sami Atalay, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6666-6671
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Catalytic reaction Esterification
Résumé :	The liquid phase esterification of acrylic acid with different alcohols (butanol, iso-butanol, or hexanol) was investigated in a batch reactor with zirconia supported tungstophosphoric acid (TPA) as heterogeneous catalyst. The prepared catalysts with different TPA loadings (20, 25, and 30 wt %) and calcination temperatures (550, 650, and 750 °C) were characterized by nitrogen adsorption studies, X-ray diffraction (XRD), and thermogravimetric analysis (TGA) techniques. In addition, acidity measurements were performed by potentiometric titration with n-butylamine. The activitiy of catalysts strongly dependent on the acidic characteristic of the catalysts. The most active catalyst, 25 wt % TPA, calcined at 650 °C, gave more than 33%, 31%, and 27% conversions of acrylic acid for butyl, iso-butyl, and hexyl acrylate synthesis, respectively.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=25900220

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6658–6665

Titre :	Removal of thiophenic sulfurs using an extractive oxidative desulfurization process with three New phosphotungstate catalysts
Type de document :	texte imprimé
Auteurs :	Hongxing Zhang, Auteur ; Jiajun Gao, Auteur ; Hong Meng, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6658–6665
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Thiophenic sulfurs Desulfurization process
Résumé :	Three Keggin-type phosphotungstates, i.e. [C5H5NH]3PW12O40, [C4H6N2H]3PW12O40·3C4H6N2 and [(C4H9)4N]3PW12O40, were synthesized and characterized by elemental analysis, X-ray diffraction, and infrared spectra, meanwhile their catalysis in an extractive catalytic oxidative desulfurization process was studied with ionic liquid (IL) as extractant and H2O2 as oxidant. The main factors affecting the desulfurization process were investigated, including temperature, hydrophobicity of IL, and variety of S-compounds, as well as the amount of catalyst, IL, and H2O2. Under the optimal conditions, the S-content of DBT oil can be decreased from 1000 to 2 ppm. A new interpretation is proposed for the current process, in which IL is assumed as a reaction phase, and the amount of the extracted S-compound and the peroxidized catalyst wherein greatly affect the desulfurization rate. Besides, the IL with the dissolved catalyst can be reused many times and regenerated easily.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie3004545

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6648-6657

Titre :	Study of the relationship between framework cation levels of Y zeolites and behavior during calcination, steaming, and n - heptane cracking processes
Type de document :	texte imprimé
Auteurs :	Bashir Y. Al-Zaidi, Auteur ; Richard J. Holmes, Auteur ; Arthur A. Garforth, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6648-6657
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Cracking Calcining Zeolite
Résumé :	The synthesis process and production of forms of the Y zeolite (i.e., NaY, NH4Y, HY, and USY) have been studied in depth, in order to investigate the thermal stability of the Y structure throughout calcination, steaming, and cracking processes. The results indicate that an increase in the cation content within the Y framework during calcination and/or steaming processes led to an increase in the catalyst stability and a reduction in the rate of any associated dehydroxylation reactions. It was also found that the presence of sodium ions hindered the extraction of Al atoms from the crystal lattice structure during the steaming treatment, which minimized partial and/or entire structural collapse at high temperatures. Finally, enhancements in the distribution of the acid sites, and an increase in the activity and selectivity of the produced USY catalysts during n-C7 cracking reactions, have also been observed.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=25900218

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6641-6647

Titre :	Heterogeneous selective oxidation of sulfides with H2O2 catalyzed by ionic liquid - based polyoxometalate salts
Type de document :	texte imprimé
Auteurs :	Pingping Zhao, Auteur ; Mingjue Zhang, Auteur ; Yajing Wu, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6641-6647
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Ionic liquid Catalytic reaction Hydrogen peroxide Oxidation
Résumé :	A group of ionic liquid (LL)-based polyoxometalate (POM) salts were prepared via anion-exchange of imidazolium LL precursors tethered by different carbon chain alkyls with various Keggin POMs. The resultant imidazolium POM salts were tested as the catalysts for oxidation of sulfides with aqueous H2O2. For understanding the POM salt-catalyzed oxidation of sulfides, catalyst compositions, substrates, and reaction conditions were changed. The results show that the imidazolium POM salts are very active and selective heterogeneous catalysts for oxidations of sulfides, adding the advantages of convenient recovery, steady reuse, simple preparation, and flexible composition. Characterizations by Fourier transform infrared (FT-IR), ultraviolet-visible (UV―vis), X-ray diffraction (XRD), and elemental analysis further reveal that the heterogeneous nature of the oxidation processes associates with the good crystallinities of the butyl- and hexyl-functionalized imidazolium POM salts and the hydrogen bonding networks among cations and anions. The POM salts' excellent performances arise from the promoted redox property of the POM-anions by the intramolecular charge transfer from the IL-cations.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=25900217

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6631–6640

Titre :	A statistical approach to microkinetic analysis
Type de document :	texte imprimé
Auteurs :	Pieter van Helden, Auteur ; Jan-Albert van den Berg, Auteur ; Roelof L. J. Coetzer, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6631–6640
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Microkinetic Analysis
Résumé :	An in-depth understanding of fundamental heterogeneous catalysis can be obtained by the use of Microkinetic Analysis of the elementary reaction steps. Unfortunately, for complex reaction networks, the sheer number of parameters present in such models can make the interpretation and deeper understanding of such microkinetic models very difficult. In this work, a Microkinetic Analysis Methodology, which incorporates statistical methods, is demonstrated, with application to a typical set of fundamental catalytic reactions. A uniform statistical experimental design is implemented, varying a selection of parameters within the microkinetic model. The responses of the simulated model are fitted to construct approximation models. We illustrate the extension of some known methods in order to successfully implement the proposed methodology, such as Kriging approximation models applied to additive log-ratio transformations of the surface coverage compositions, as well as a multivariate scaled EIGF criterion to iteratively improve the global model fit. We demonstrate that the methodology yields statistical approximation models that are capable of yielding accurate predictions of the complete parameter space. The proposed methodology can be applied to any number of microkinetic model parameters of interest.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie2013086

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6625-6630

Titre :	Complete reduction of polychlorinated biphenyls by acid - etched steel wool in supercritical carbon dioxide
Type de document :	texte imprimé
Auteurs :	Yun-Chieh Chen, Auteur ; Weisheng Liao, Auteur ; Hwa-Kwang Yak, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6625-6630
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Supercritical state Carbon dioxide Steel
Résumé :	Inexpensive household steel wool was used as a reducing agent for the reductive dechlorination of polychlorinated biphenyls (PCBs) in supercritical carbon dioxide (scCO2). Untreated steel wool does not produce significant results. Steel wool treated with 6 N HCl, however, showed complete reduction of the PCBs (Aroclor 1254) used. Scanning electron microscopy (SEM) reveals the formation of nanoscale pits (nanopits) on the surface of steel wool after etching with HCl. These nanopits are responsible for the high efficiency of the hydrodechlorination process.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=25900215

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6619-6624

Titre :	Cyclic imide dioximes : Formation and hydrolytic stability
Type de document :	texte imprimé
Auteurs :	Sung Ok Kang, Auteur ; Sinisa Vukovic, Auteur ; Radu Custelcean, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6619-6624
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Stability
Résumé :	Poly(acrylamidoximes) play an important role in the uranium extraction from seawater. The present work reports solution studies of simple analogues to address the formation and stability of two binding sites present in these polymers, open-chain amidoximes and cyclic imide dioximes, including: (1) conditions that maximize the formation of the cyclic form, (2) the existence of a base-induced conversion from open-chain to cyclic form, and (3) degadation under acid and base conditions.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=25900214

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6613–6618

Titre :	Facile method for determination of amine speciation in CO2 capture solutions
Type de document :	texte imprimé
Auteurs :	Naser S. Matin, Auteur ; Joseph E. Remias, Auteur ; James K. Neathery, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6613–6618
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Amine Capture solutions
Résumé :	A simple and quantitatively reliable method for determination of amine speciation is introduced. The method employs three experimental methods that should be readily accessible. The results for CO2 loaded aqueous solutions of 30 wt % monoethanolamine (MEA) are used for demonstration of the method and show promising agreement with the more complicated spectroscopic methods reported in the literature. The measurements were done at ambient temperature and atmospheric pressure, since theoretical calculations and experimental data from the open literature revealed no considerable difference in speciation at different temperatures. The procedure is based on acid and base titration of the CO2 loaded amine solution along with the determination of total CO2 loading. The quantitative results for the different species concentration in the example MEA solution is in agreement with other available spectroscopic methods, mainly NMR, particularly for the free amine, carbamate, and protonated amine concentrations. Aspen Plus was also used for further assessment of the experimental data.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie300230k

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6605-6612

Titre :	Supersaturation - controlled synthesis of dicalcium phosphate dihydrate and nanocrystalline calcium - deficient hydroxyapatite
Type de document :	texte imprimé
Auteurs :	F. Lagno, Auteur ; S.D.F. Rocha, Auteur ; L. Katsarou, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6605-6612
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Hydroxyapatite Supersaturation
Résumé :	The homogeneous and seed-assisted precipitation of dicalcium phosphate dihydrate (DCPD or brushite) and hydroxyapatite (HAP) under controlled supersaturation regimes in chloride media at room temperature (22 °C) is investigated. Prior to their reactive crystallization the metastable zones of precipitation for the two calcium orthophosphates were determined. The effects of supersaturation, reaction time, and seeding on the stoichiometry and crystallinity of these compounds were studied. Acidified solutions (pH ≈ 2.0) of NaH2PO4 (2-90 mmol/L) and CaCl2 (2-150 mmol/L) were mixed in order to get Ca to P molar ratios in initial solution of 1.0 or 1.67 (the stoichiometric ratios for dicalcium phosphate dihydrate and hydroxyapatite).The supersaturation in solution was built up by the slow addition of 100 mmol/L NaOH solution. In seed-assisted precipitation tests (Ca/P = 1) the metastable calcium phosphate solution (37.5 mmol/L) was neutralized until the precipitation pH of 5 was reached and 10 g/L of seed was added. The homogeneous precipitation of DCPD at pH 5.4 was fast and equilibrium was reached in 30 min. In the presence of seed, the precipitation rate was slower due to reduced supersaturation. Even so, in both cases well crystalline plate-like crystals matching the stoichiometry of brushite were produced. Calcium-deficient hydroxyapatite with nanocrystalline structure (nanocrystallite size ∼20 nm) was produced at pH 7.6 under controlled supersaturation. The homogeneously produced material consisted of irregularly shaped agglomerates of the order of 5―15 μm while the product obtained by seed-assisted precipitation was in the form of rather coarse (ca. 20―30 μm) and dense spheroids. The highest Ca:P ratio material (Ca:P = 1.58) was obtained with seed-assisted precipitation at a slow addition rate.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=25900212

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6599-6604

Titre :	Hydrotreating of phenolic compounds separated from bio - oil to alcohols
Type de document :	texte imprimé
Auteurs :	Jianhua Guo, Auteur ; Renxiang Ruan, Auteur ; Ying Zhang, Auteur
Année de publication :	2012
Article en page(s) :	pp. 6599-6604
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Hydrotreating
Résumé :	Phenolic compounds in bio-oil are not stable and difficult to be upgraded to ideal fuels. In this study, simulated bio-oil as well as phenolic compounds separated from bio-oil by glycerol-assisted distillation were hydrotreated by Ru/SBA-15 catalyst and completely converted into C3 to C10 alcohols at mild conditions, which could be a feasible way to transfer the phenolic compounds in bio-oil or other real systems from lignin decomposition into high heating-value liquid fuel or fuel additives. The stability of the Ru/SBA-15 catalyst was also investigated. It was found that Ru/SBA-15 was stable with phenolic compounds in the simulated bio-oil but not in a real one.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=25900211

Industrial & engineering chemistry research / Paul, Donald R. . Vol. 51 N° 19

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