Catalogue en ligne Bibliothèque Ecole Nationale Polytechnique d'Alger

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9350–9353

Titre :	Solid acid catalyst for biodiesel production from waste used cooking oils
Type de document :	texte imprimé
Auteurs :	Cholada Komintarachat, Auteur ; Sathaporn Chuepeng, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9350–9353
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Waste Methanol Cooking oils
Résumé :	This paper presents a study of the methanol based transesterification of waste used cooking oil (WCO, 15% free fatty acid content) with the synthesized solid acid catalyst at different temperatures and reaction times. The optimized conditions for fatty acid methyl ester (FAME) yield were investigated using methanol/WCO weight ratios of 0.15−0.35 and catalyst/WCO ratios of 0.25−1.25%. The results show that the methanol/WCO ratio of 0.3 and the catalyst/WCO ratio of 1.0% give the highest yield of 97.5% FAME at 383 K in 2 h. In addition, the capacity of porous supports for WOx synthesized catalysts, based on FAME yield was in the following order: Al2O3 > SiO2 > SnO2 > ZnO. The WOx/Al2O3 catalyst was found to be readily reusable and exhibited consistency in activity upon reuse for three times without loss of selectivity.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901175d

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9346–9349

Titre :	Removal of thiophene from coking benzene over SO42−/Fe2O3 solid acid under mild conditions
Type de document :	texte imprimé
Auteurs :	Zhanjiang Kang, Auteur ; Hongzhu Ma, Auteur ; Bo Wang, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9346–9349
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Thiophene DesulfurizationSolid superacid
Résumé :	Desulfurization of thiophene in coking benzene with n-butanol as an alkylating agent over SO42−/Fe2O3 solid superacid at 353 K and atmospheric pressure was investigated. The acidity of the catalyst was measured by temperature-programmed desorption (TPD) of ammonia, and the result confirms that the SO42−/Fe2O3 catalyst has a high acid strength. The sample after reaction was detected by gas chromatography−mass spectrometry (GC-MS), and the results show that thiophene has been removed completely.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901075t

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9338–9345

Titre :	Some physical properties and structure determination of vinyl monomer-grafted antheraea assama silk fiber
Type de document :	texte imprimé
Auteurs :	A. M. Das, Auteur ; P. K. Chowdhury, Auteur ; C. N. Saikia, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9338–9345
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Vinyl monomer Antheraea assama silk fiber
Résumé :	Vinyl monomer was used in aqueous medium with CeIV initiator for chemical modification of Antheraea assama silk fiber at different reaction conditions. The rate of grafting (%) was evaluated as a function of the concentration of monomer (AAm) and initiator (CeIV). The graft copolymerization of silk-fibroin with vinyl monomer (acryl amide) were characterized with Fourier transform infrared spectroscopy (FT-IR) and UV−vis spectroscopy (UV). Thermal analysis was done by thermogravimetric (TG), differential thermogravimetry (DTG), and differential scanning calorimetry (DSC) techniques. The kinetic parameters were also studied using Coats and Redfern method with Fortran 77 computer programming. The structural changes of the silk molecule, grafted with vinyl monomer, were studied in relation to the weight gain and X-ray diffraction curves. Moreover, the grafted products were further evaluated to see the improvement in water staining, water retention capacity, and also tensile properties.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9004755

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9335–9337

Titre :	Characterization of the clathrate hydrate formed with methane and propan-1-ol
Type de document :	texte imprimé
Auteurs :	Keita Yasuda, Auteur ; Satoshi Takeya, Auteur ; Mami Sakashita, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9335–9337
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Clathrate hydrate Methane Propane-1-ol X-ray diffraction Raman spectroscopic measurements
Résumé :	This paper reports the identification of the crystallographic structure of the clathrate hydrate formed in a system of methane + propan-1-ol + water. A hydrate crystal sample was prepared with a 0.0556 mole fraction aqueous solution of propan-1-ol pressurized with methane and then subjected to powder X-ray diffraction and Raman spectroscopic measurements. The X-ray diffraction pattern thus obtained from the sample indicated that the crystallographic structure of the hydrate was structure II. The Raman spectra thus obtained from the same sample indicated that the methane molecules occupied not only 512 cages but also 51264 cages.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900954w

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9331–9334

Titre :	General spectroscopic protocol to obtain the concentration of the superoxide anion radical
Type de document :	texte imprimé
Auteurs :	Rui-heng Liu, Auteur ; Shi-yu Fu, Auteur ; Huai-yu Zhan, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9331–9334
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Nitro Blue Tetrazolium Superoxide anion radical Spectroscopy
Résumé :	Nitro Blue Tetrazolium (NBT) is a widely used chemical for the determination of superoxide anion radical (O2−) and superoxide dismutase activity in many fundamental biological processes. Its reduction reaction with superoxide and the associated spectral absorption data of its reduction products, i.e., monoformazan (MF) and diformazan (DF), were studied in the current research. The molar extinction coefficient, ε, of each of these two reduction products in dimethyl sulfoxide (DMSO) were calculated to be 120 000 and 235 000 M−1 cm−1, respectively. We propose quantifying these species as a means of obtaining superoxide anion radical concentration or as a general screening protocol for the efficacy of an antioxidant.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9007826

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9325–9330

Titre :	Experimental liquid−liquid equilibrium of (lube cut + furfural + 2,2,4-tri-methyl pentane) ternary system from T = 323.15−343.15 K and simulation with NRTL
Type de document :	texte imprimé
Auteurs :	S. M. Fakhr Hoseini, Auteur ; M. S. Hatamipour, Auteur ; T. Tavakkoli, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9325–9330
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	2,2,4-tri methyl pentane Extraction temperature Liquid−liquid equilibrium NRTL equation
Résumé :	The use of 2,2,4-tri methyl pentane as a cosolvent for extraction of aromatic hydrocarbons from lube cut is studied. Optimized values of extraction temperature and amount of 2,2,4-tri methyl pentane are determined. The liquid−liquid equilibrium between {lube oil + furfural + cosolvent} is examined with the NRTL equation. The binary interaction parameters for the NRTL model are obtained by minimization of an objective function. General binary interaction parameters are computed and reported for estimating the liquid−liquid equilibrium products between 323.15 and 343.15 K. Also, a generalized model is presented for calculation of the refractive index and specific gravity of lube-oil fractions. The calculated results are in good agreement with the results of the experiments.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9003267

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9318–9324

Titre :	Experimental study on pressure drop and heat transfer of turbulent flow in tube in tube helical heat exchanger
Type de document :	texte imprimé
Auteurs :	Monisha Mridha Mandal, Auteur ; K. D. P. Nigam, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9318–9324
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Turbulent flow Heat transfer Fluid flow Reynolds numbers
Résumé :	In the present study, experiments were conducted for the first time in tube in tube helical heat exchanger at the pilot plant scale to investigate the fluid flow and heat transfer under turbulent flow conditions. The experiments were carried out with hot compressed air in the inner tube and cooling water in the outer tube in the countercurrent mode of operation. The flow rate of compressed air flowing in the inner tube was varied for Reynolds numbers from 14 000 to 86 000. The pressure of compressed air was varied from 10 to 30 kgf/cm2. The friction factor and Nusselt number values for compressed air flowing in the inner tube were calculated for elevated pressure and compared with the experimental data reported in the literature at ambient conditions. Most of the works reported in the literature on heat transfer in coiled tubes have been carried out considering wall boundary conditions of either constant heat flux or constant wall temperature. In the present work, heat transfer calculations were based on physically realistic condition of fluid to fluid heat transfer. The inner tube Nusselt number of compressed air in the present study was found to be slightly higher than the data reported in the literature for ambient conditions while the friction factor values are within the range reported in the literature for ambient conditions. The friction factor as well as Nusselt number calculated for cooling water flowing in the outer tube was higher than the existing literature data. On the basis of the experimental results, new correlations for friction factor and Nusselt number in the inner as well as outer tubes have been developed.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9002393

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9307–9317

Titre :	Experimental study of carbon dioxide diffusion in oil-saturated porous media under reservoir conditions
Type de document :	texte imprimé
Auteurs :	Zhaowen Li, Auteur ; Mingzhe Dong, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9307–9317
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	CO2 diffusion coefficient Oil-saturated porous media
Résumé :	For both CO2 enhanced oil recovery and CO2 sequestration in oil reservoirs, the diffusion of injected CO2 into oil-saturated porous media is of great significance in project design, risk assessments, economic evaluation, and performance forecast. However, the measurement of CO2 diffusion coefficient in liquid-saturated porous media under reservoir conditions has not been well-established due to the complications caused by density-induced natural convection in the CO2−oil systems. This paper presented a new method for measuring the effective CO2 diffusion coefficient in oil-saturated porous media under reservoir conditions. A core plug with the two end faces sealed was designed as the physical model for radial diffusion process. The measurement was conducted in a high-pressure diffusion cell with an oil-saturated core sample placed in the middle and the remaining void space of the cell filled by high-pressure CO2 sample. A small-pressure decay technique was employed to record the pressure change of the gas phase during the diffusion measurement. Because the oil phase contained in the porous medium swells as CO2 diffuses into it, the experiment essentially involves both diffusion and swelling-induced convection. To describe these processes involved in the measurement, a mathematical model along with numerical solutions was derived. The effective diffusion coefficient was determined by matching the experimental pressure decay curve with the corresponding mathematical model. The proposed method was demonstrated for oil-saturated Berea core samples at pressures ranging from 2.2 to 6.5 MPa. The measured pressure decay curves showed good agreement with the mathematical predictions using the best-fitted effective diffusion coefficients. The derived method can be readily implemented in laboratories that can handle high-pressure fluids; thus, this study provides a tool for studying CO2 diffusion in oil-saturated porous rocks.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900145c

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9299–9306

Titre :	Corrosion in CO2 capture process using blended monoethanolamine and piperazine
Type de document :	texte imprimé
Auteurs :	Manjula Nainar, Auteur ; Amornvadee Veawab, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9299–9306
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Monoethanolamine Piperazine Industrial flue gas streams Corrosion
Résumé :	This work explores the promise of aqueous solutions of blended monoethanolamine (MEA) and piperazine (PZ) as a cost-effective solvent for carbon dioxide (CO2) capture from industrial flue gas streams with respect to corrosion, which is regarded as one of the most severe operational problems in typical CO2 capture plants. Electrochemical corrosion experiments were carried out using the potentiodynamic polarization technique for corrosion measurements. The results show that the blended MEA/PZ solutions are more corrosive than the MEA solutions. The corrosion rate of carbon steel increases with concentration of PZ, total amine concentration, CO2 loading of solution, solution temperature, and the presence of heat stable salts. Among the tested heat-stable salts, formate is the most corrosive salt, followed by acetate, oxalate, and thiosulfate in the absence of oxygen (O2), while acetate is the most corrosive salt followed by formate, oxalate, and thiosulfate in the presence of O2.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801802a

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9286–9298

Titre :	New type of draft tube spout-fluid bed. Part 1: hydraulic transport of 1.94 mm glass particles in water
Type de document :	texte imprimé
Auteurs :	Howard Littman, Auteur ; John D. Paccione, Auteur ; Joel L. Plawsky, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9286–9298
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Draft tube spout-fluid bed Fluid mass flow rate Dynamic pressure drop
Résumé :	A new type of draft tube spout-fluid bed (DTSFB) is described in which the draft tube physically separates the particle feeder section from the particle separator section as seen in Figure 2, creating an extremely versatile fluid/solids processing apparatus. This arrangement, denoted a type 2 DTSFB, allows the fluid mass flow rate in the draft tube and the dynamic pressure drop across it to be independently specified. As a result, the solids mass flow rate in the draft tube can be set and/or varied by changing the solids fraction, the particle velocity, or both. An additional property of this new DTSFB is that the effluents from the draft tube and annulus do not mix. Either stream can be collected or recycled as needed. In addition, the unit is easily controlled and scaled, and fluid−particle processing can be conducted in the draft tube, annulus, fluid−particle separator, or a combination of all of these. Equations are presented and sample calculations made to show how this new DTSFB works and how the solids fraction and particle velocity in the draft tube are set and varied. The data of Grbavčić et al. (Can. J. Chem. Eng. 1992, 71, 895−905) form the basis for the sample design calculations presented for a water-driven type 2 DTSFB. It is also shown that three independent variables capable of specifying the total mass fluid flow rate entering the inlet section, the split in that flow between the draft tube and annulus surrounding the draft tube and the dynamic pressure drop across the draft tube completely specifies the fluid and particle flows. Basic control schemes are outlined. A general equation is derived for calculating the maximum superficial fluid velocity allowable in the annulus (Ua,max). That velocity must be less than (UmF − ϵava). Calculations demonstrate the effects of varying the total fluid mass flow rate supplied to the inlet section, the split of that fluid flow rate between the draft tube and the annulus, and the effect of the solids fraction and the dynamic pressure drop across the draft tube. Other calculations showing the effect of feeding all the inlet fluid flow to the draft tube provides a means for calculating the bounding limits that the annulus flow has on the operation of a type 2 DTSFB. Finally, we show the maximum particle circulation rate in the draft tube for a given fluid velocity in the annulus that will result in incipient fluidization of the annulus solids.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9001475

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9278–9285

Titre :	Investigation of the gas layer height in a multistage internal-loop airlift reactor
Type de document :	texte imprimé
Auteurs :	Wei Yu, Auteur ; Tiefeng Wang, Auteur ; Feifei Song, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9278–9285
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Multistage internal-loop airlift reactor Interstage internal Gas layer
Résumé :	A novel multistage internal-loop airlift reactor was realized by using a novel interstage internal. In this reactor, a gas layer is formed below the internal and has important effects on the hydrodynamic behavior. The effects of the opening ratio of the internal for the gas and liquid channels and superficial gas and liquid velocities were experimentally studied in both cocurrent and countercurrent operations. The results show that the gas layer height increases with an increase in the superficial gas velocity for both cocurrent and countercurrent flows. With an increase in the superficial liquid velocity, the gas layer height decreases for cocurrent flow, but increases for countercurrent flow. The opening ratio of the internal for gas channels has a much more significant influence on the gas layer height than that for the liquid channel. A mathematical model for predictions of the gas layer height was proposed based on the balance between the pressure drops of the gas and liquid through the internal. A good agreement was obtained between the calculated and experimental data. This model can be used for the optimum design of the novel multistage internal-loop airlift reactor.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9002156

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9268–9277

Titre :	Simulation and optimal design of electrodeionization process : separation of multicomponent electrolyte solution
Type de document :	texte imprimé
Auteurs :	Anjushri S. Kurup, Auteur ; Thang Ho, Auteur ; Jamie A. Hestekin, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9268–9277
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Electrodeionization technology Ultrapure water Electrolyte solutions
Résumé :	Electrodeionization (EDI) technology combines the operation principle of both ion exchange and electrodialysis in one single unit and overcomes the disadvantages of either unit. This technology has been widely used in the production of ultrapure water due to its better performance and economical operation at low feed concentrations. As a result, there have been several studies that deal with application of this technology for the removal of ions from water. However, except for a few studies, most of the reported works deal with the experimental study of EDI. This study deals with the development of a mathematical model for deionization of electrolyte solutions containing more than one ion and ions that are multivalent in nature. The model validity is verified by comparing the results with a few experimental observations. This is followed by a sensitivity study of the EDI unit to explore the effect of various operating and system parameters on the ion removing ability of the EDI unit. Consequently, a systematic optimization exercise that can simultaneously handle more than one objective for superior system performance of the experimental unit is demonstrated. Due to the optimization study, it is shown that many times EDI is not operated at optimized conditions and decreasing the flow rate, among other variables, might have a significant effect on system performance.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801906d

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9261–9267

Titre :	Modeling study on absorption of CO2 by aqueous solutions of N-methyldiethanolamine in rotating packed bed
Type de document :	texte imprimé
Auteurs :	Zhi Qian, Auteur ; Lianbin Xu, Auteur ; Huibo Cao, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9261–9267
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	CO2 absorption N-methyldiethanolamine Rotating packed bed
Résumé :	The work presents a theoretical investigation of the absorption of CO2 by aqueous solutions of N-methyldiethanolamine (MDEA) in a rotating packed bed (RPB). The diffusion-reaction process for CO2-MDEA mass transfer in RPB is modeled according to Higbie’s penetration theory with the assumption that all reactions are reversible. A three-dimensional distribution of carbon dioxide concentration varying with the time and penetration depth in liquid film and an average mass transfer rate at interface are obtained. The intensification within the RPB is mainly achieved by the sharper concentration profile of the dissolvable gas in liquid film; the short lifetime of liquid film resulting from frequent renewal of the film on packing surface significantly increases the mass transfer coefficient. Experiments were carried out at various rotating speeds, liquid flow rates, and temperatures in RPB. The validity of this model is demonstrated by the fact that most of the predicted yout (mole fraction of CO2 in outlet gas) agree well with the experimental data with a deviation within 4%. Besides, this study makes a quantitative comparison between dynamic- and static-state mass transfer coefficients for this reactive absorption and a discussion on their applicability.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900894a

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9247–9260

Titre :	Adsorption/desorption of water and ethanol on 3A zeolite in near-adiabatic fixed bed
Type de document :	texte imprimé
Auteurs :	Marian Simo, Auteur ; Siddharth Sivashanmugam, Auteur ; Christopher J. Brown, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9247–9260
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Pilot scale adsorber Water Ethanol Adsorption/desorption kinetics
Résumé :	A pilot scale adsorber apparatus was designed and constructed to investigate water and ethanol adsorption/desorption kinetics on 3A zeolite for the design purposes of a fuel ethanol dehydration pressure swing adsorption (PSA) process. Equilibrium studies have shown that 3A zeolite adsorbed a significant amount of water while very weak ethanol adsorption was observed. The breakthrough curves were utilized to study the effects of column pressure, temperature, flow rate, pellet size, and adsorbate concentration on the overall mass transfer resistance. Based on experimentally observed trends, both macropore and micropore diffusion were identified as relevant mass transfer mechanisms. A mathematical model for a bench scale adsorption bed included the linear driving force (LDF) adsorption rate model and the variation of axial velocity. A detailed heat transfer model was a necessity since the bed dynamics was affected by heat transfer in the bed wall. The model was used to analyze the experimental data and extract values of pertaining diffusion coefficients.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900446v

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9233–9246

Titre :	Rate-based process modeling study of CO2 capture with aqueous monoethanolamine solution
Type de document :	texte imprimé
Auteurs :	Ying Zhang, Auteur ; Hern Chen, Auteur ; Chau-Chyun Chen, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9233–9246
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Rate-based process modeling technology Pilot plant operation Aspen RateSep
Résumé :	Rate-based process modeling technology has matured and is increasingly gaining acceptance over traditional equilibrium-stage modeling approaches. [Taylor et al. Chem. Eng. Prog. 2003, 99, 28−39] Recently comprehensive pilot plant data for carbon dioxide (CO2) capture with aqueous monoethanolamine (MEA) solution have become available from the University of Texas at Austin. The pilot plant data cover key process variables including CO2 concentration in the gas stream, CO2 loading in lean MEA solution, liquid to gas ratio, and packing type. In this study, we model the pilot plant operation with Aspen RateSep, a second generation rate-based multistage separation unit operation model in Aspen Plus. After a brief review on rate-based modeling, thermodynamic and kinetic models for CO2 absorption with the MEA solution, and transport property models, we show excellent match of the rate-based model predictions against the comprehensive pilot plant data and we validate the superiority of the rate-based models over the traditional equilibrium-stage models. We further examine the impacts of key rate-based modeling options, i.e., film discretization options and flow model options. The rate-based model provides excellent predictive capability, and it should be very useful for design and scale-up of CO2 capture processes.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900068k

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9224–9232

Titre :	On the selection of limiting hydrodynamic conditions for the supercritical antisolvent (SAS) process
Type de document :	texte imprimé
Auteurs :	Alvaro Tenorio, Auteur ; Philip Jaeger, Auteur ; Maria D. Gordillo, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9224–9232
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Supercritical antisolvent technique Active pharmaceutical compounds Thermodynamic properties
Résumé :	The Supercritical AntiSolvent (SAS) technique (which is also referred to as ASES, PCA, or SEDS in the literature) is a promising means of overcoming the low bioavailability found in some active pharmaceutical compounds (APIs). By determining the thermodynamic properties of the phases involved in the process, and applying empirical equations (operations with dimensionless numbers), it has been possible to estimate the different disintegration regimes of the jet when an N-methyl-pyrrolidone (NMP)−ampicillin solution is injected into the CO2-pressurized chamber under pressure (P), temperature (T), and flow rate (QL) conditions in the following ranges: P = 80−180 bar, T = 308−328 K, QL = 1−5 mL/min. The application of the empirical hydrodynamics model highlights the existence of significant mechanisms that stabilize the liquid jet, and it shows that there are limiting hydrodynamic conditions that must be overcome to direct the process toward the formation of uniform spherical nanoparticles and the achievement of higher yields.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801940p

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9215–9223

Titre :	Nanocomposite MFI−alumina membranes : high-flux hollow fibers for CO2 capture from internal combustion vehicles
Type de document :	texte imprimé
Auteurs :	M. Pera-Titus, Auteur ; A. Alshebani, Auteur ; C H. Nicolas, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9215–9223
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Transport field accounts CO2 emission pattern High-flux nanocomposite MFI−alumina membranes
Résumé :	The transport field accounts for about 35% of CO2 emissions in France, while energy production only involves 16% of the emissions. The strong contribution of transport to the CO2 emission pattern in France is mainly ascribed to the great development of the nuclear field as energy vector. Therefore, in order to meet Kyoto targets, CO2 emissions in vehicles should be drastically reduced in France in the forthcoming decades. To this aim, taking into account a scenario where thermal engines will keep their supremacy as the main propulsion technology at short and mid terms, in addition to increasing more and more energy efficiency, a possibility to reduce drastically CO2 emissions from transport could involve direct CO2 capture and in situ storage from exhaust gases. In this study, we propose the use of high-flux nanocomposite MFI−alumina hollow-fiber membranes recently developed in our laboratory for direct CO2 capture from mobile sources. A critical discussion is provided about the technico-economical feasibility (i.e., CO2 recovery, CO2 purity in the permeate, module volume, energy overcomsumption, and autonomy) of a membrane-based unit for CO2 capture and liquefaction in the special case of heavy vehicles (over 3500 kg) using conventional diesel propulsion standards.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9004018

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9204–9214

Titre :	Robustness measures for operation schedules subject to disruptions
Type de document :	texte imprimé
Auteurs :	Badarinath Karri, Auteur ; Rajagopalan Srinivasan, Auteur ; Iftekhar A. Karimi, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9204–9214
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Operation schedules Robustness Disruptions
Résumé :	Operation schedules are frequently subject to disruptions or uncertainties that render them suboptimal or even infeasible to implement. Among the approaches that address stochastics in schedules, preventive methods incorporate uncertainty in the scheduling model to develop an a priori robust solution, while reactive techniques seek to repair the schedule after a disruption has occurred. In this work, an alternate perspective to schedules subject to disruptions is propounded. We seek to quantify robustness of a given schedule. Given a schedule and information about the possible disruptions, we evaluate its robustness in terms of the outcome for each possible disruption scenario. The consequent action(s) required on the part of the planner/scheduler, such as complete rescheduling, schedule repair, or none, is then identified and serves as the basis to classify the scenario into tiers. Robustness metrics are proposed based on the distribution of the tiers. Malleability is an indicator of a schedule’s ability to provide the performance as in the nominal case. Brittleness is a measure of the schedule’s feasibility and reschedulability under disruptions. These metrics are independent of economic indicators such as profit that are typically objectives in scheduling algorithms and can therefore be used as additional criteria to compare schedules. The proposed framework is illustrated using a refinery crude oil scheduling problem. Further, sensitivity studies are conducted to identify critical resources and disruption classes. Such studies can directly help a planner/scheduler to choose the best schedule overall for implementation and take preventive measures to safeguard critical elements.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900505a

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp.

Titre :	Pressure-driven dynamic simulation for improving the performance of a multistage compression system during plant startup
Type de document :	texte imprimé
Auteurs :	Xiongtao Yang, Auteur ; Qiang Xu, Auteur ; Chuanyu Zhao, Auteur
Année de publication :	2010
Article en page(s) :	pp.
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Multistage compression systems Pressure-driven dynamic simulations Plant startup
Résumé :	Multistage compression systems (MSCS) are the most important and valuable facilities in chemical plants, whose failure may cause severe accidents and/or tremendous economic loss. Thus, operation for MSCS needs sufficient care under various situations, especially during plant startup. This paper employs rigorous pressure-driven dynamic simulations to examine and improve operation safety of the cracked gas compression system during an ethylene plant startup. For safety consideration, antisurge process design and control strategies are dynamically evaluated along with startup procedures. Operating point trajectory for each compressor and their potential safety problems are identified. Assisted by the rigorous dynamic simulation, the plant startup procedure is improved with better safety performance.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900212v

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9186–9194

Titre :	Particle swarm optimization algorithm for a batching problem in the process industry
Type de document :	texte imprimé
Auteurs :	Lixin Tang, Auteur ; Ping Yan, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9186–9194
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Particle swarm optimization algorithmBatch processing plant
Résumé :	An improved particle swarm optimization (PSO) algorithm is proposed to solve a typical batching problem in a batch processing plant of the process industry. The batching problem (BP) is to transform the primary requirements for products into sets of batches for each task with the objective of minimizing the total workload. On the basis of some preliminary properties, a novel particle solution representation is designed for the BP. Unlike the ordinary idea of taking an objective function as the fitness function for PSO, the original objective function incorporated with a constraint function is to act as the fitness function of the PSO where the constraint and the objective functions are evaluated successively. Such a fitness function, together with a forward repair mechanism, makes it possible for a faster convergence. Further, for each iterative generation, a local search heuristic is used to improve the global best particle found so far. To verify the performance of the proposed PSO algorithm, the well-known benchmark batching instances are tested. The relatively large-scale instances are also added to evaluate the algorithm. The computational results show that the improved PSO may find optimal or suboptimal solutions within a much shorter run time for all the instances.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801742m

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9175–9185

Titre :	Multivariable control with generalized decoupling for disturbance rejection
Type de document :	texte imprimé
Auteurs :	Feng-Yi Lin, Auteur ; Jyh-Cheng Jeng, Auteur ; Huang, Hsiao-Ping, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9175–9185
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Multivariable controllers MIMO decoupler
Résumé :	In this paper, a systematic procedure to design multivariable controllers that have options for selective decoupling of different structures (e.g., full or partial decoupler) is proposed. The controller structure is determined based on an analysis of relative load gain (RLG). For controller design, the adjoint of a template matrix is provided to design the MIMO decoupler that is needed for a given process. In the case where decoupling is desirable, according to the number of zero deficiency that the adjoint of the template matrix has, a pole-zero compensator is incorporated to preserve the properness of the decoupling controller and to define the decoupled open-loop dynamics. By incorporating the decoupler, the controller in the main loop is synthesized for disturbance rejection. Stability robustness of the system is tuned using measures of modeling errors in the decoupled open-loop process. Simulation examples are used to illustrate the proposed method and show its effectiveness in disturbance rejection in MIMO systems.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801477z

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9163–9174

Titre :	Nonlinear batch process monitoring using phase-based kernel-independent component analysis−principal component analysis (KICA−PCA)
Type de document :	texte imprimé
Auteurs :	Zhao, Chunhui, Auteur ; Gao, Furong, Auteur ; Wang, Fuli, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9163–9174
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Nonlinear batch processes Kernel technique
Résumé :	In this article, the statistical modeling and online monitoring of nonlinear batch processes are addressed on the basis of the kernel technique. First, the article analyzes the conventional multiway kernel algorithms, which were just simple and conservative kernel extensions of the original multiway linear methods and thus inherited their drawbacks. Then, an improved nonlinear batch monitoring method is developed. This method captures the changes of the underlying nonlinear characteristics and accordingly divides the whole batch duration into different phases. Then, focusing on each subphase, both nonlinear Gaussian and non-Gaussian features are explored by a two-step modeling strategy usingkernel-independent component analysis−principal component analysis (KICA−PCA). Process monitoring and fault detection can be readily carried out online without requiring the estimation of future process data. Meanwhile, the dynamics of the data are preserved by exploring time-varying covariance structures. The idea and performance of the proposed method are illustrated using a real three-tank process and a benchmark simulation of fed-batch penicillin fermentation production.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8012874

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9151–9162

Titre :	Design of hybrid distillation-vapor membrane separation systems
Type de document :	texte imprimé
Auteurs :	Jose A. Caballero, Auteur ; Ignacio E. Grossmann, Auteur ; Majid Keyvani, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9151–9162
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Hybrid separation system Distillation column separation Parallel membrane separation Two-stage approach
Résumé :	Currently the separation of olefins (ethylene, propylene) from (ethane, propane) on a commercial scale is performed almost exclusively by cryogenic distillation in petrochemical industries. Since this technology is highly energy intensive, there is a strong economic incentive to explore alternative separation technologies with lower energy consumption. In this work, using the separation of ethylene and ethane as a representative case, a mathematical programming approach is proposed to optimize and retrofit a hybrid separation system consisting of a distillation column and a parallel membrane separation unit. A two-stage approach is used. First, a shortcut model is introduced that allows determining whether the hybrid system could be of interest and the order of magnitude of the energy savings that can be expected. Second, a superstructure optimization approach is proposed that uses rigorous models for both the column and the membrane using a process simulator and state of the art MINLP solvers. The results presented in the case study show that significant savings in total costs and energy (up to 30%) can be obtained with the hybrid system.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900499y

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9141–9150

Titre :	Stable model predictive control for integrating systems with optimizing targets
Type de document :	texte imprimé
Auteurs :	Luz A. Alvarez, Auteur ; Erika M. Francischinelli, Auteur ; Bruno F. Santoro, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9141–9150
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Model predictive controller Real time optimization
Résumé :	This paper concerns the development of a stable model predictive controller (MPC) to be integrated with real time optimization (RTO) in the control structure of a process system with stable and integrating outputs. The real time process optimizer produces optimal targets for the system inputs and/or outputs that should be dynamically implemented by the MPC controller. This paper is based on a previous work (Comput. Chem. Eng. 2005, 29, 1089) where a nominally stable MPC was proposed for systems with the conventional control approach where only the outputs have set points. This work is also based on the work of Gonzalez et al. (J. Process Control 2009, 19, 110) where the zone control of stable systems is studied. The new controller is obtained by defining an extended control objective that includes input targets and zone control for the outputs. Additional decision variables are also defined to increase the set of feasible solutions to the control problem. The hard constraints resulting from the cancellation of the integrating modes at the end of the control horizon are softened, and the resulting control problem is made feasible to a large class of unknown disturbances and changes of the optimizing targets. The methods are illustrated with the simulated application of the proposed approaches to a distillation column of the oil refining industry.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900400j

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9128–9140

Titre :	Optimal Reference Trajectory Shaping and Robust Gain-Scheduling for Transition Control of Nonlinear Processes
Type de document :	texte imprimé
Auteurs :	Pietro Altimari, Auteur ; Lucia Russo, Auteur ; Erasmo Mancusi, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9128–9140
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Nonlinear processes Transition control Gain scheduling
Résumé :	A novel method for transition control of nonlinear processes is presented. Gain scheduling is implemented to ensure stability and desired output behavior over the operating region of interest while transition between the initial and the final steady state is achieved by predictive reference control (or reference governor). In this framework, the search of a feasible reference input sequence is performed so that the closed-loop system moves along an optimal curve of steady states. This curve is constructed off-line so that its points lie far from the border of the process constraint set and correspond to satisfactory controllability properties of the uncontrolled plant. Moreover, bifurcation analysis of the closed-loop system is performed by varying the reference signal according to the selected curve. In this way, regions of state multiplicity and/or instability are identified enabling the choice of the controller parameters values preventing transitions to undesired solution regimes. The method is validated on a simulated problem of start-up control of a jacketed continuous stirred tank reactor.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9001553

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9119–9127

Titre :	Branch-and-cut algorithmic framework for 0-1 mixed-integer convex nonlinear programs
Type de document :	texte imprimé
Auteurs :	Hao Wu, Auteur ; Hao Wen, Auteur ; Yushan Zhu, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9119–9127
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Branch-and-cut algorithmic framework Mixed-Integer Nonlinear Optimizer Nonlinear programming
Résumé :	With widespread use of mixed-integer modeling for continuous and discontinuous nonlinear chemical processes, a robust mixed-integer nonlinear optimization algorithm is strongly demanded for the design and operation of chemical processes that achieve greater profits and also satisfy environmental and safety constraints. In this article, an extensive evaluation of a branch-and-cut algorithmic framework for 0−1 mixed-integer convex nonlinear programs, called MINO for Mixed-Integer Nonlinear Optimizer, is presented. The numerical performances of MINO are tested against four sets of medium-sized practical application problems from the fields of operations research and chemical engineering. The effects of the nonlinear programming (NLP) solvers, the cut generating and maintaining strategy, the node selection method, and the frequency of cut generation are examined, in order to handle MINLP problem with different mathematical structures. Preliminary computational results show that MINO exhibits a capability for handling practical MINLP problems that is comparable to that of the commercial solvers SBB and DICOPT, and it shows better performance for some problems for which either commercial solver encounters convergence problem within a CPU time limit of 6 h.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9001074

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9113–9118

Titre :	Isothermal carbon dioxide sorption in poly(ionic liquid)s
Type de document :	texte imprimé
Auteurs :	Jianbin Tang, Auteur ; Youqing Shen, Auteur ; Maciej Radosz, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9113–9118
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Poly(ionic liquid)s CO2 Isothermal sorption
Résumé :	The low-pressure isothermal sorption of CO2 in poly(ionic liquid)s (PILs) with varied structures including different cations, anions, backbones, and substituents was investigated to probe structure effects on the CO2 sorption. An ammonium cation with short alkyl group, BF4 anion, and polystyrene backbone was found to favor CO2 sorption in PILs. CO2 sorption in the PILs fitted the dual-mode model very well, suggesting that the CO2 sorption consists of dissolution in the polymer matrix and Langmuir sorption in the microvoids.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900292p

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9106–9112

Titre :	Importance of cellulosic fines relative to the dewatering rates of fiber suspensions
Type de document :	texte imprimé
Auteurs :	Hao Chen, Auteur ; Andrew Park, Auteur ; John A. Heitmann, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9106–9112
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Cellulosic fines Fiber suspensions
Résumé :	When cellulosic fines are present in significant amounts, they can have a dominant influence on dewatering. Pulp suspensions drain rapidly if the fines have been removed. In this study, the dependency of gravity dewatering rates on the level and properties of cellulosic fine matter was quantified. Bleached hardwood kraft pulp was used as a source of primary fines (collected before refining) and secondary fines (collected after refining of fines-free fiber suspensions). Fractions of fine matter also were obtained from chemithermomechanical (CTMP) pulp. Size distributions of these fines were characterized using a laser diffraction method. Results were explainable by a mechanism in which unattached fines are able to move relative to adjacent fibers during the dewatering and consolidation of a mat of fibers. Due to such movement, fines end up in locations where they plug drainage channels in the mat. The contribution of the fines to dewatering increased in inverse proportion to particle size and with increasing surface area, as calculated from the light scattering analysis.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9006613

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9097–9105

Titre :	Scope of metal loaded microporous ZSM-5 zeolites in the “catazone” process of n-hexadecane at moderate conditions
Type de document :	texte imprimé
Auteurs :	V. S. R. Rajasekhar Pullabhotla, Auteur ; S. B. Jonnalagadda, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9097–9105
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Metal loaded microporous materials n-hexadecane
Résumé :	The saturated hydrocarbons, alkanes, are known to exhibit extremely low reactivity, and reactions are feasible only at high temperature and pressure conditions. The scope of metal loaded microporous materials, ZSM-5, as catalysts in the ozone initiated oxyfunctionalization of n-hexadecane is investigated at 20 ± 1 °C and ∼1 atm. The efficiencies of 0.5% Pd, Ni, and V loaded microporous ZSM-5 catalysts on ozonation of n-hexadecane, with respect to the conversion, reaction products, and selectivity were compared. This paper emphasizes that the “Catazone” process of long chained alkanes to their corresponding 4-, 3-, and 2-keto products at moderate conditions is of significance, in that hitherto unreactive n-alkanes can be functionalized via ozonation catalytically.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900228x

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp.

Titre :	Effect of partial carbonation on the cyclic CaO carbonation reaction
Type de document :	texte imprimé
Auteurs :	Gemma Grasa, Auteur ; Juan Carlos Abanades, Auteur ; Edward J. Anthony, Auteur
Année de publication :	2010
Article en page(s) :	pp.
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	CaO particles Carbonation
Résumé :	CaO particles from the calcination of natural limestones can be used as regenerable solid sorbents in some CO2 capture systems. Their decay curves in terms of CO2 capture capacity have been extensively studied in the literature, always in experiments allowing particles to reach their maximum carbonation conversion for a given cycle. However, at the expected operating conditions in a CO2 capture system using the carbonation reaction, a relevant fraction of the CaO particles will not have time to fully convert in the carbonator reactor. This work investigates if there is any effect on the decay curves when CaO is only partially converted in each cycle. Experiments have been conducted in a thermobalance arranged to interrupt the carbonation reaction in each cycle before the end of the fast reaction period typical in the CaO−CO2 reaction. It is shown that, after the necessary normalization of results, the effective capacity of the sorbent to absorb CO2 during particle lifetime in the capture system slightly increases and CaO particles partially converted behave “younger” than particles fully converted after every calcination. This has beneficial implications for the design of carbonation/calcination loops.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900443y

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9083–9089

Titre :	Catalytic performance and characterization of silica supported sodium phosphates for the dehydration of methyl lactate to methyl acrylate and acrylic acid
Type de document :	texte imprimé
Auteurs :	Zhiqiang Zhang, Auteur ; Yixin Qu, Auteur ; Shui Wang, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9083–9089
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Methyl lactate Acrylic acid Methyl acrylate Dehydration Supported sodium phosphates
Résumé :	Dehydration of methyl lactate (ML) to methyl acrylate (MA) and acrylic acid (AA) over silica supported sodium phosphates was investigated in a fixed-bed continuous flow reactor. On NaH2PO4/SiO2 a significantly higher selectivity to MA + AA than on Na2HPO4/SiO2 and Na3PO4/SiO2 was observed. For NaH2PO4/SiO2, there is an optimum loading of NaH2PO4, with which a higher selectivity to MA + AA could be obtained. It was found that the ratio of Na2O to P2O5 of the phosphates influenced the catalyst performance in the conversion of ML. The catalysts were characterized using XRD, Raman, NMR, and NH3-TPD techniques. The higher selectivity for the dehydration of ML to MA + AA on NaH2PO4/SiO2 is assumed to be related to the acidity and the amount of the terminal POH groups on the polyphosphate chains.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900065a

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9076–9082

Titre :	Synthesis of titanium-containing mesoporous silicas as catalysts for cyclohexene epoxidation
Type de document :	texte imprimé
Auteurs :	Verónica R. Elías, Auteur ; Mónica E. Crivello, Auteur ; Eduardo R. Herrero, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9076–9082
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Ti-containing mesoporous materials Hydrothermal synthesis
Résumé :	Ti-containing mesoporous materials have been prepared by hydrothermal synthesis at 100 °C with two different Si/Ti ratios (20 and 60) in the synthesis mixture. A detailed study about the effect of synthesis time on the physicochemical properties of the materials has been carried out. The samples were characterized by XRD, DRUVvis, N2 adsorption, and pyridine adsorption analyzed by FT-IR. The samples synthesized using the lower Si/Ti ratio presented the higher titanium incorporation and the higher acid character. The synthesis time appears as an important parameter that affects the textural, structural, chemical, and acid properties of the final solids. For the lower Si/Ti ratio, a longer synthesis time is needed to obtain a more ordered structure. However, in both cases, short synthesis times do not allow a proper incorporation of titanium into the silica framework, which is reached with synthesis times of about 3 days. The results of catalytic activity indicate that the solids studied here present an interesting potential as catalysts in the selective oxidation of cyclohexene using H2O2.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8018017

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9068–9075

Titre :	New amines for CO2 capture. II. oxidative degradation mechanisms
Type de document :	texte imprimé
Auteurs :	Helene Lepaumier, Auteur ; Dominique Picq, Auteur ; Pierre-Louis Carrette, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9068–9075
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Ethylenediamines Ethanolamines Oxidative degradation
Résumé :	This study examines oxidative degradation of 12 ethanolamines and ethylenediamines. They were chosen to establish structure−property relationships: the role of replacement of the alcohol function by one second amine function, amine nature, steric hindrance, and cyclic structure were studied. Degradation of aqueous amine solutions was evaluated at 140 °C under air pressure (2 MPa) in stainless steel reactors for 15 days. At the end of the run, most degradation products were identified by gas chromatography (GC)/mass spectrometry (MS); amounts of remaining amine and its degradation products were determined with the quantitative GC method. Main degradation mechanisms are proposed, and some relationships between structure and chemical stability are given.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9004749

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp.

Titre :	New amines for CO2 capture. I. mechanisms of amine degradation in the presence of CO2
Type de document :	texte imprimé
Auteurs :	Helene Lepaumier, Auteur ; Dominique Picq, Auteur ; Pierre-Louis Carrette, Auteur
Année de publication :	2010
Article en page(s) :	pp.
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Amines CO2 Ethanolamines
Résumé :	Degradation of 12 different amines with CO2 was evaluated in 100 mL stainless steel batch reactors for 15 days at 140 °C using a 4 mol·kg−1 amine solution and a CO2 pressure of 2 MPa. At the end of the run, most of degradation products were identified by gas chromatography (GC)/mass spectrometry (MS); amounts of starting amine and its degradation products were determined with a quantitative GC method. This work compares the degradation of ethanolamines (including MEA) having one or two hydroxyl groups with the degradation of ethylenediamines. They were chosen to establish relationships between amine structure and stability properties: replacement of one alcohol function by one amine function, effect of amine function nature, impact of steric hindrance and cyclic structure. Significant differences were observed. The main degradation products are described, and some mechanisms are proposed to explain their formation.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900472x

Industrial & engineering chemistry research / Paul, Donald R. . Vol. 48 N° 20

Exemplaires

Bibliothèque Ecole Nationale Polytechnique d'Alger

Accueil

Sélection de la langue

Se connecter

Météo

Adresse

Horaires d'ouverture :