Catalogue en ligne Bibliothèque Ecole Nationale Polytechnique d'Alger

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10156–10162

Titre :	Butene oligomerization over phosphoric acid : structural characterization of products
Type de document :	texte imprimé
Auteurs :	Riaan Bekker, Auteur ; Nicolaas M. Prinsloo, Auteur
Année de publication :	2010
Article en page(s) :	pp. 10156–10162
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Butene oligomerate Posphoric acid GC-MS techniques
Résumé :	In this study, the butene oligomerate produced over solid (SPA) and liquid phosphoric acid (LPA) was analyzed in detail using GC-MS techniques in conjunction with reported retention time data to identify the alkene isomers in the C6 to C8 fractions produced by the reaction. This information was used to quantify the oligomerate produced over liquid and solid phosphoric catalysts at different temperatures to identify subtle differences between the product distributions. It is hoped that this information will assist in future studies of the oligomerization reaction since several interesting trends that can be linked to previously proposed mechanisms were observed. Group classification of the identified alkenes according to the number of branches identified tetrasubstituted alkenes as compounds that form in large amounts during the reaction, but these are also removed through cracking faster than the other classes at higher temperatures.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900210q

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10152–10155

Titre :	Hydrolysis and decomposition of cellulose in brönsted acidic ionic liquids under mild conditions
Type de document :	texte imprimé
Auteurs :	Ananda S. Amarasekara, Auteur ; Onome S. Owereh, Auteur
Année de publication :	2010
Article en page(s) :	pp. 10152–10155
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Brönsted acidic ionic liquids Cellulose dissolves
Résumé :	Cellulose dissolves in Brönsted acidic ionic liquids 1-(1-propylsulfonic)-3-methylimidazolium chloride and 1-(1-butylsulfonic)-3-methylimidazolium chloride up to 20 g/100 g ionic liquid by gentle mixing at room temperature. Hydrolysis of cellulose can be carried out in these ionic liquid solutions by the addition of 2.0 equiv of water per glucose unit of cellulose and heating the solution at 70 °C and at atmospheric pressure with or without preheating to give glucose along with other reducing sugars. The hydrolysis of Sigmacell cellulose (DP ∼ 450) in 1-(1-propylsulfonic)-3-methylimidazolium chloride produced the highest total reducing sugar (62%) and glucose (14%) yields and was attained in 1 h of preheating at 70 °C and 30 min of heating at 70 °C, after adding water.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901047u

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10147–10151

Titre :	Comparison of emulsification devices for the production of miniemulsions
Type de document :	texte imprimé
Auteurs :	Ula El-Jaby, Auteur ; Michael Cunningham, Auteur ; Timothy F. L. McKenna, Auteur
Année de publication :	2010
Article en page(s) :	pp. 10147–10151
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Emulsification devices Miniemulsions
Résumé :	Droplets generated using ultrasonication, the rotor-stator, and static mixers have been investigated in terms of power and energy consumption, droplet distributions, and shear rates. It was observed that with energy costs being of similar orders of magnitude, the static mixers imposed less shear on the system making them the optimal choice for miniemulsification. Similarly, the absolute widths of the distributions for droplets generated with the sonicator and rotor-stator were larger than those generated with the static mixers and during polymerization underwent secondary nucleation.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901005a

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10136–10146

Titre :	Determination of actual object size distribution from direct imaging
Type de document :	texte imprimé
Auteurs :	Md. Iqbal Hossain, Auteur ; Tao Chen, Auteur ; Yanhui Yang, Auteur
Année de publication :	2010
Article en page(s) :	pp. 10136–10146
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Direct imaging Dynamic system
Résumé :	Direct imaging is a technique commonly used in the study of particle, bubble, and droplet size distribution in a dynamic system. Objects such as particles, bubbles, and droplets can be present at various distances from the imaging device when images are captured. Hence, the location of the object will need to be known in order to determine the actual size of an individual object. However, the location of the object cannot be determined from a single image. A single calibration scale defined at the focusing plane is normally used for the determination of all the object sizes from images. When the focus is close to the imaging device, the change in magnification with location is large. The size distribution obtained from the use of a single calibration scale would thus give a considerable deviation from the actual size distribution. In this study, a statistical method is proposed to reconstruct the actual object size distribution from the experimental object size distribution obtained from images using a single calibration scale defined at the focusing plane. Experiments are performed to validate the accuracy of the proposed method on the particle size distribution determination in a settling system. The stability of the proposed method is also analyzed theoretically for imaging devices with different depth-of-field (DOF), focusing location, and change in magnification with distance.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900857m

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10129–10135

Titre :	Prediction of density and viscosity of bitumen using the Peng−Robinson equation of state
Type de document :	texte imprimé
Auteurs :	Herbert Loria, Auteur ; Pedro Pereira-Almao, Auteur ; Marco Satyro, Auteur
Année de publication :	2010
Article en page(s) :	pp. 10129–10135
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Bitumen Thermodynamic models Peng−Robinson equation
Résumé :	Density and viscosity are important quantities required in engineering design for production, fluid transportation, and processing. However, there is no satisfactory theory for the calculation of these properties for bitumen. The principal objective of this paper is to obtain thermodynamic models to predict the density and viscosity of bitumen on the basis of the translated version of the Peng−Robinson equation of state. In the density calculation, a consistent correction to improve the liquid-phase volume estimation was applied. The density model evidenced a small percent average absolute error regarding experimental data (less than 1%). The model for viscosity was based on a modification of the Enskog’s equation. This modification allowed the prediction of bitumen viscosity using an equation of state along with a substance- and temperature-dependent parameter; this approach showed good accuracy with respect to experimental data. An important advantage of these models is the possibility of estimating viscosities at different pressures.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901031n

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10120–10128

Titre :	Re-investigation and data assessment of the isomerization and 2,2′-cyclization of stilbenes and azobenzenes
Type de document :	texte imprimé
Auteurs :	Heiko K. Cammenga, Auteur ; Vladimir N. Emel’yanenko, Auteur ; Sergey P. Verevkin, Auteur
Année de publication :	2010
Article en page(s) :	pp. 10120–10128
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Azobenzenes StilbenesCis/trans-isomerization
Résumé :	The energetics and kinetics of the thermal and photochemical cis/trans-isomerization of azobenzenes and stilbenes are of fundamental interest to physical organic chemistry, because they may serve as “reference reactions” for the various theoretical and computational methods. The same applies to the 2,2′-cyclization of these compounds to benzo(c)cinnolines and phenanthrenes. Although many investigations have been devoted to this topic, a wide variety of energetic data for these fundamental processes can be found in the literature. This paper presents both a compilation and assessment of all data hitherto published and a consistent data redetermination for these fundamental processes.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900800q

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10110–10119

Titre :	Thermophysical properties of dry and humid air by molecular simulation including dew point calculations with the mollier ensemble
Type de document :	texte imprimé
Auteurs :	Bernhard Eckl, Auteur ; Thorsten Burkhardt, Auteur ; Jadran Vrabec, Auteur
Année de publication :	2010
Article en page(s) :	pp. 10110–10119
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Mollier ensemble Humid air systems Thermophysical properties
Résumé :	A pseudoensemble, the Mollier ensemble, is proposed for the dew point calculation of humid air systems. This approach combines features of the isobaric−isothermal (NpT) ensemble and the grand-canonical (μVT) ensemble. The molecular model for dry air is taken from previous work and compared to experimental data as well as to two recommended reference quality equations of state regarding vapor−liquid equilibria, thermal, and caloric properties. An excellent agreement is found for temperatures up to 1000 °C and pressures up to 200 MPa. For water, two different molecular models are considered, the popular TIP4P model from the literature and an optimized version that better describes the vapor pressure. Both water models are used in combination with the molecular dry air model to predict the compressed gas density as well as the dew point of humid air at 60 and 80 °C for elevated pressures up to 25 MPa. The results are in very good agreement with experimental data from the literature.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9005707

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10104–10109

Titre :	Preparation of silver nanoparticles using a spinning disk reactor in a continuous mode
Type de document :	texte imprimé
Auteurs :	Clifford Y. Tai, Auteur ; Yao-Hsuan Wang, Auteur ; Chia-Te Tai, Auteur
Année de publication :	2010
Article en page(s) :	pp. 10104–10109
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Spinning disk reactor Silver nanoparticles Hydroxypropylmethyl cellulose poly(vinylpyrrolidone) cellulose
Résumé :	A spinning disk reactor (SDR) operated in a continuous mode was adopted for producing silver nanoparticles, aiming at an increase in the production rate. Two protecting agents, i.e., poly(vinylpyrrolidone) (PVP) and hydroxypropylmethyl cellulose (HPMC), were tested, which have been proven to be effective in our previous work of recycle operation. Using PVP as protecting agent, the effects of the operating variables, including the rotation speed, the feeding rate, the dosage of protecting agent, and reactant concentration, on the particle size and yield of the silver product were investigated. The experiment was further conducted using HPMC as protecting agent to compare the experimental results between the two protecting agents. The use of PVP gave smaller silver nanoparticles; however, a higher yield was obtained by using HPMC. Although the yield of continuous operation was lower than that of recycle operation, the production rate was much higher for either protecting agent, providing a great potential for commercialization.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9005645

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10094–10103

Titre :	Modeling of multiphase flow and heat transfer in radiant syngas cooler of an entrained-flow coal gasification
Type de document :	texte imprimé
Auteurs :	Guangsuo Yu, Auteur ; Jianjun Ni, Auteur ; Qinfeng Liang, Auteur
Année de publication :	2010
Article en page(s) :	pp. 10094–10103
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Résumé :	A comprehensive model has been developed to analyze the multiphase flow and heat transfer in the radiant syngas cooler (RSC) of an industrial-scale entrained-flow coal gasification. The three-dimensional multiphase flow field and temperature field were reconstructed. The realizable k−ϵ turbulence model is applied to calculate the gas flow field, while the discrete random walk model is applied to trace the particles, and the interaction between the gas and the particle is considered using a two-way coupling model. The radiative properties of syngas mixture are calculated by weighted-sum-of-gray-gases model (WSGGM). The Ranz−Marshall correlation for the Nusselt number is used to account for convection heat transfer between the gas phase and the particles. The discrete ordinate model is applied to model the radiative heat transfer, and the effect of ash/slag particles on radiative heat transfer is considered. The model was successfully validated by comparison with the industrial plant measurement data, which demonstrated the ability of the model to optimize the design. The results show that a torch shape inlet jet was formed in the RSC, and its length increased with the diameter of the central channel. The recirculation zones appeared around the inlet jet, top, and bottom of the RSC. The overall temperature decreased with the heat-transfer surface area of the fins. The concentration distribution, velocity distribution, residence time distribution, and temperature distribution of particles with different diameters have been discussed. Finally, the slag/ash particles size distribution and temperature profile at the bottom of the RSC have been presented.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901203d

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10087–10093

Titre :	Biomass-derived platform chemicals: thermodynamic studies on the conversion of 5-hydroxymethylfurfural into bulk intermediates
Type de document :	texte imprimé
Auteurs :	Sergey P. Verevkin, Auteur ; Vladimir N. Emel’yanenko, Auteur ; Elena N. Stepurko, Auteur
Année de publication :	2010
Article en page(s) :	pp. 10087–10093
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	5-hydroxymethylfurfural Bulk intermediates
Résumé :	This work was undertaken to obtain new thermochemical data for 5-hydroxymethylfurfural (HMF) and parent compounds. The standard molar enthalpy of formation in the gaseous state of HMF was obtained from combustion calorimetry, differential scanning calorimetry (DSC), and measurements of the temperature dependence of the vapor pressure by the transpiration method. To verify the experimental data, ab initio calculations of all compounds were performed. Enthalpies of formation derived from the G3MP2 method are in an excellent agreement with the experimental results. A weak hydrogen bond in HMF was revealed using ab initio methods. Thermodynamic analysis of the transformation of HMF to the bulk intermediates according to hydrogenation and oxidation pathways has revealed a very high feasibility of these reactions, with equilibrium constants that are completely shifted to the desired reaction products even at 298 K.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901012g

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10077–10086

Titre :	Validation of ultrafilter performance model based on systematic simulant evaluation
Type de document :	texte imprimé
Auteurs :	R. L. Russell, Auteur ; J. M. Billing, Auteur ; H. D. Smith, Auteur
Année de publication :	2010
Article en page(s) :	pp. 10077–10086
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Ultrafilter performance model Simulant evaluation
Résumé :	Because of limited availability of test data with actual Hanford tank-waste samples, a method was developed to estimate expected filtration performance based on physical characterization data for the Hanford Tank Waste Treatment and Immobilization Plant. This method relies upon the similarity between the gel concentration measured during crossflow filtration and the slurry concentration measured after a sample is centrifuged. Testing was performed to determine the centrifuged-solids concentration, and then a subset of simulants was tested to determine the gel concentration during crossflow filtration. These two approaches produced identical results, indicating the centrifuged-solids concentration can be used to represent the gel concentration for filtration. This substitution will allow the expected filtration performance to be characterized at a significantly reduced cost.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901042w

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10065–10076

Titre :	Thermophysical properties of binary and ternary mixtures containing lactams and methanol
Type de document :	texte imprimé
Auteurs :	María J. Dávila, Auteur ; Santiago Aparicio, Auteur ; Rafael Alcalde, Auteur
Année de publication :	2010
Article en page(s) :	pp. 10065–10076
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Binary mixtures Ternary mixtures Lactams Methanol
Résumé :	Thermophysical properties of 2-pyrrolidone (PYR), N-methyl-2-pyrrolidone (NMP), and N-cyclohexyl-2-pyrrolidone (CHP) binary and ternary liquid mixtures with methanol are reported at 298.15 K and 0.1 MPa over the full composition range. Excess and mixing properties derived from the experimental ones were correlated using Redlich−Kister (RK) equation, for binary mixtures, and Cibulka (C) equation, for ternary ones. Density Functional Theory (DFT) was also used to analyze structural and energetic features of cyclic lactams in gas phase and methanol solution. Results show the formation of H-bonding and dipolar interactions between cyclic amides and methanol, although these are weakened when a third component is added to the binary mixture, thus decreasing remarkably the values of ternary properties in comparison with binary ones and leading to the weakening of the binary blends’ intermolecular interactions.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900822e

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10055–10064

Titre :	Experimental study of the effect of particle density on mixing behavior in a spout-fluid bed
Type de document :	texte imprimé
Auteurs :	Baosheng Jin, Auteur ; Yong Zhang, Auteur ; Wenqi Zhong, Auteur
Année de publication :	2010
Article en page(s) :	pp. 10055–10064
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Mixing behavior Spout-fluid bed Experimental study
Résumé :	The particle mixing behavior has been investigated experimentally in a spout-fluid bed. The bed material used is polypropylene particles, and the tracer employed is chosen from silica gel, mung beans, and glass beads. During all experiments, the completely segregated arrangement of particles is adopted as the initial packing condition. The gas velocity varies to cover internal jet, minimum spouting, and fully developed spouting conditions, in order to establish a full mixing map about the effect of particle density. The mixing behavior is analyzed in terms of flow patterns, concentration profile, and mixing index. The results show that the degree and rate of mixing are significantly affected by the particle density, and heavier particles achieve a higher mixing rate but a poorer mixing quality. The mixing map reveals that to reach the same mixing index, the spouting gas velocity needs to increase with the increase of particle density. Besides, provided that the jet gas velocity does not exceed the minimum spouting gas velocity, a segregation phenomenon can always be observed by simply adjusting the ratio of the fluidizing to spouting gas velocity.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900689r

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10047–10054

Titre :	Residence time distribution of liquid and solid phases in a novel staged crystallizer
Type de document :	texte imprimé
Auteurs :	Zai Qun Yu, Auteur ; Pui Shan Chow, Auteur ; Reginald B. H. Tan, Auteur
Année de publication :	2010
Article en page(s) :	pp. 10047–10054
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Staged crystallizer
Résumé :	A novel vertically staged continuous crystallizer is proposed in this work. It consists of a series of compartments stacked one above another with partition plates in between. A stirrer shaft with multiple impellers provides agitation in each compartment. Solution to be crystallized enters the crystallizer from the top and flows downward through all stages. Crystal product and mother liquor are collected from the bottom. Openings in partition plates with accessories attached serve as passages for slurry flow, allowing for control over interstage mixing of liquid phase and residence time distribution (RTD) of crystals. The hydrodynamics of such a crystallizer is investigated in a two-stage experimental setup. Water, PVC particles, and glass beads are used to investigate the influences of design and operating factors on interstage mixing of liquid phase and RTDs of both liquid and solid phases. Results show that interstage mixing of liquid phase can be repressed successfully to ensure the establishment of supersaturation gradient across stages. RTD of solid phase can be manipulated by adjusting the feeding rate of liquid phase and opening size in the partition plate. Average residence time of solids deceases with increasing particle size, leading to classification of particles. A model is proposed for the RTD of solid phase which agrees with experimental data very well.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9006722

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10037–10046

Titre :	Simultaneous removal of urea, ammonia, and carbon dioxide from industrial wastewater using a thermal hydrolyzer−separator loop
Type de document :	texte imprimé
Auteurs :	Rahimpour, M. R., Auteur ; H. R. Mottaghi, Auteur
Année de publication :	2010
Article en page(s) :	pp. 10037–10046
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Industrial wastewater Hydrolyzer−separator loop
Résumé :	In this work, simultaneous removal of urea, ammonia, and carbon dioxide from industrial wastewater was studied via modeling and simulation of a hydrolyzer−separator loop. The extended electrolytic UNIQUAC equation has been used to describe the nonideality of the liquid phase and the perturbed-hard-sphere (PHS) equation of state has been applied to predict the vapor fugacity coefficients. This work also uses a multistage well-mixed model for the liquid and vapor flows with a nonideal rate-based model for urea thermal hydrolyzer. Our study incorporates the reaction rate of urea hydrolysis and takes into account the effects of solution nonideality and backmixing on the reactor performance. The rates of urea reaction are written in terms of activity of reactants. The model provides temperature and flow rate distributions of different components along the height of the hydrolysis reactor and the desorbers. The simulation results have been found to be in good agreement with the plant data indicating the validity of the model. The impact of different parameters on the performance of the wastewater treatment loop has been examined. The results of this work showed that an increase in the inlet temperature of the wastewater and steam flow rate and also decrease the reflux ratio would improve the urea and ammonia removal efficiency.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900751g

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10025–10036

Titre :	On the fluid mechanics of spiral-wound membrane modules
Type de document :	texte imprimé
Auteurs :	M. Kostoglou, Auteur ; Anastasios J. Karabelas, Auteur
Année de publication :	2010
Article en page(s) :	pp. 10025–10036
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Spiral-wound membrane modules Fluid mechanics
Résumé :	Spiral-wound membrane (SWM) modules are comprised of several large-size membrane sheets with a net-type spacer at the retentate flow channel and a porous cloth/filler at the low-pressure permeate side; thus, two strongly interacting flow fields exist with spatially variable properties. Mathematical models of the SWM operation, based on an accurate description of transport phenomena taking place in those narrow flow passages, are necessary tools for optimizing both module design parameters and the entire membrane-based plant. Such integrated SWM models are not available at present. In this problem, the coexistence of several flow length scales, from the pores of the permeate side filler to the macroscopic dimensions of the module, renders the modeling task quite complicated. Typical modeling efforts vary between the extremes of detailed description of transport phenomena at small scale to macroscopic phenomenological-type simulation of the entire separation process in a module. The scope of this work is to describe the hydrodynamics of spiral-wound membranes, starting from first principles, to suggest and analyze some realistic approximations and their origin and to present an integrated model where linking phenomena at different length scales is an essential feature. This effort has resulted in an efficient numerical algorithm, allowing predictions of the spatial distribution of pressure, permeation, and cross-flow velocities throughout the membrane leaves. In this work, all possible analytical solutions have been derived which facilitate the development of the simulation algorithm. Typical examples of predicted flow and pressure distributions are presented.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901129j

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10021–10024

Titre :	Correlation of crystal lattice expansion and membrane properties for MFI zeolites
Type de document :	texte imprimé
Auteurs :	Stephanie G. Sorenson, Auteur ; Joseph R. Smyth, Auteur ; Richard D. Noble, Auteur
Année de publication :	2010
Article en page(s) :	pp. 10021–10024
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	MFI zeolites Correlation X-ray diffraction measurements
Résumé :	X-ray diffraction measurements show that saturation loadings of C5−C13 n-alkanes at room temperature increased the unit cell size of silicalite-1 crystals, and the percent volume expansion correlated linearly with the number of carbon atoms per unit cell. Adsorption of tridecane expanded the zeolite the most (1.53 vol %), but all n-alkanes and alcohols studied expanded MFI crystals. Pervaporation fluxes of isooctane through defects in B-ZSM-5 membranes at 313 K decreased 2 orders of magnitude when n-alkanes were added to the feed, and the percentage decrease correlated with crystal expansion; n-alkanes that expanded crystals more caused the flux through defects to decrease more.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901073g

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10015–10020

Titre :	Adsorption and diffusion of carbon dioxide on metal−organic framework (MOF-5)
Type de document :	texte imprimé
Auteurs :	Zhenxia Zhao, Auteur ; Zhong Li, Auteur ; Y. S. Lin, Auteur
Année de publication :	2010
Article en page(s) :	pp. 10015–10020
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Microporous metal−organic framework Adsorption equilibrium Diffusion
Résumé :	Adsorption equilibrium and diffusion of CO2 on microporous metal−organic frameworks (MOF-5, or IRMOF-1) crystals were experimentally studied by the gravimetric method in the pressure range up to 1 atm. The MOF-5 crystal cubes of about 40−60 μm in sizes were synthesized by the solvothermal method. Freundlich adsorption isotherm equation can fit well CO2 adsorption isotherms on MOF-5, with isosteric heat of adsorption of about 34 kJ/mol. Diffusion coefficient of CO2 in the MOF-5 is in the range of 8.1−11.5 × 10−9 cm2/s in 295−331K with activation energy of 7.61 kJ/mol. MOF-5 offers attractive adsorption properties as an adsorbent for separation of CO2 from flue gas.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900665f

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10008–10014

Titre :	Mass transfer enhancement in liquid−liquid extraction with very dilute aqueous salt solutions
Type de document :	texte imprimé
Auteurs :	Javad Saien, Auteur ; Fatemeh Ashrafi, Auteur
Année de publication :	2010
Article en page(s) :	pp. 10008–10014
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Liquid−liquid extraction chemical system Mass transfer
Résumé :	The effect of very low salt addition in the recommended liquid−liquid extraction chemical system of toluene−acetone−water was investigated with circulating single drops and in both of the mass transfer directions. By adding sodium chloride, potassium chloride, and potassium iodide, within the concentration range of 10−6−10−4 mol/L, into the continuous phase and under constant pH, the mass transfer rate finds enhancements to about 425%. A high trend of variation was observed for the salt concentrations until only about 10−5 mol/L. This phenomenon can be attributed to the hydration of ions which favors acetone to be transferred easier in the aqueous phase. Small drops are usually more benefited, and the rate of mass transfer is greater for the dispersed to continuous phase direction under similar conditions due to a higher dominant extraction fraction, whereas the drop size decreases in this direction. The effectiveness of salts in this matter appeared to be in the order of NaCl > KCl > KI.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900542w

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9999–10007

Titre :	Integrated analysis of energy, economic, and environmental performance of biomethanol from rice straw in China
Type de document :	texte imprimé
Auteurs :	Jun Xiao, Auteur ; Laihong Shen, Auteur ; Yanan Zhang, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9999–10007
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Rice straw process Biomethanol China
Résumé :	This paper focuses on a biomethanol from the rice straw process involving the thermodynamic, economic, and environmental performance in China. Based on the simulation of methanol synthesis via biomass gasification in interconnected fluidized beds using Aspen Plus software, the method of LCA (Life Cycle Assessment) is applied to evaluate the impact of pollutant emissions in the full life cycles of biomethanol. The integrated performance of biomethanol system is analyzed combining with energy utilization, economic cost, and environmental impact. The results show that the methanol yield can reach 0.308 kg/(kg rice straw), i.e., the energy efficiency of rice straw conversion to biomethanol is approximately 42.7%. For a biomethanol plant with an annual production of 50,000 tons, the real cost of biomethanol is evaluated at 2685 RMB/t, in which the economic cost is 2347 RMB/t, and the environmental cost is 337.6 RMB/t. Because of its high investment cost, presently the economic cost of biomethanol is higher than that of coal-based methanol in China. Nevertheless biomethanol will be becoming more competitive with the shortage of fossil fuel in the future. In the whole life cycle, the main pollutant emissions come from the biomethanol production process and biomethanol end-use by automobiles, whereas the net environmental effect is negative during the rice cultivation. Global warming is the most influential factor of the different impact categories. However, 1910 kg of CO2 can be fixed for one ton of methanol by photosynthesis in the growth of rice, thus the effect of global warming is significantly reduced by biomass utilization compared with coal-based methanol. The integrated performance indicates that producing methanol from rice straw is beneficial to both the utilization of agriculture waste and in the improvement of environment.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900680d

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9985–9998

Titre :	Methodology for designing and comparing robust linear versus gain-scheduled model predictive controllers
Type de document :	texte imprimé
Auteurs :	Rosendo Diaz-Mendoza, Auteur ; Jianying Gao, Auteur ; Hector Budman, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9985–9998
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Gain-Scheduled Model Predictive Control Nonlinear state-affine model Stability
Résumé :	A methodology is proposed to design a robust Gain-Scheduled Model Predictive Control (MPC) strategy and to quantify the relative advantages of this controller versus a Linear MPC strategy. For the purpose of analysis and controller design, the process is represented by a nonlinear state-affine model identified from input−output data. This model can be split in linear and nonlinear terms where the linear part is used for controller design and the nonlinear part is accounted for as model uncertainty. Then, robust stability and robust performance tests are formulated based on linear matrix inequalities where the manipulated variables weight of the controllers is tuned to maximize performance. The uncertainty bounds used for the robustness tests are obtained in an iterative fashion by using the frequency response of the manipulated variable with respect to the feedback error. The control strategy performance is quantified by the ratio between the error norm and the disturbance norm. Finally, a case study involving a multiple-input−multiple-output bioreactor is presented. The study is able to predict for which range of operation the Gain-Scheduling MPC surpasses the performance of the Linear MPC.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900309s

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9979–9984

Titre :	Efficient numerical solver for partially structured differential and algebraic equation systems
Type de document :	texte imprimé
Auteurs :	Flavio Manenti, Auteur ; Ivan Dones, Auteur ; Guido Buzzi-Ferraris, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9979–9984
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Differential and algebraic equations Sparse set
Résumé :	Given a sparse set of differential and algebraic equations (DAEs), it is always recommended to exploit the structure of the system’s sparsity (e.g., tridiagonal blocks matrix, band matrix, and staircase matrix, etc.), thus to use tailored numerical solvers in order to reduce the computation time. Very frequently, though, while highly structured, a couple of elements enter the description which make it difficult for the solvers to reach a solution. They are common in process control applications, where the states added to the plant description by the integral parts of the controllers introduce unstructured elements in the otherwise very structured Jacobian of the mathematical model. Such systems are characterized by a partially structured Jacobian, which inhibits the use of the solvers tailored to fit problems with fully structured matrices. In such cases, one can either use a solver with lower performance, resulting in larger computation times, or alternatively one seeks an approximation for the unstructured points. A solution to the handling of “dirty” Jacobians is presented, which is implemented in a DAE solver package available freely on the Internet. This novel DAE solver fully exploits the overall structure of the system’s sparsity, without compromising CPU computation time and precision of the results. A numerical comparison with different approaches is given by solving a DAE model representing an existing nonequilibrium distillation column.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9007908

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9961–9978

Titre :	Managing distribution in supply chain networks
Type de document :	texte imprimé
Auteurs :	Rodolfo Dondo, Auteur ; Carlos A. Méndez, Auteur ; Jaime Cerdá, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9961–9978
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Multiechelon multiproduct transportation networks Chemical supply chains
Résumé :	This paper presents a novel optimization approach to the short-term operational planning of multiechelon multiproduct transportation networks. Distribution activities commonly arising in real-world chemical supply chains involve the shipping of a number of commodities from factories to customers directly and/or via distribution centers and regional warehouses. To optimally manage such complex distribution systems, a more general vehicle routing problem in supply chain management (VRP-SCM) has been defined. The new VRP-SCM problem better resembles the logistics activities to be planned at multisite manufacturing firms by allowing multiple events at every location. In this way, two or more vehicles can visit a given location to perform pickup and/or delivery operations, and vehicle routes may include several stops at the same site, i.e., multiple tours per route. More important, the allocation of customers to suppliers and the quantities of products shipped from each source to a particular client are additional model decisions. Both the capacitated vehicle routing problem (VRP) and the pickup-and-delivery problem (PDP) can be regarded as particular instances of the new VRP-SCM. The proposed MILP mathematical formulation for the VRP-SCM problem relies on a continuous-time representation and applies the general precedence notion to model the sequencing constraints establishing the ordering of vehicle stops on every route. The approach provides a very detailed set of optimal vehicle routes and schedules to meet all product demands at minimum total transportation cost. Several examples involving up to 26 locations, four products, and six vehicles housed in four different depots have been solved to optimality in very short CPU times.
En ligne :	This paper presents a novel optimization approach to the short-term operational [...]

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9952–9960

Titre :	Measurements and correlation of octyltriethoxysilane solubility in supercritical CO2 and assembly of functional silane monolayers on the surface of nanometric particles
Type de document :	texte imprimé
Auteurs :	Carlos A. García-González, Auteur ; Julio Fraile, Auteur ; Ana López-Periago, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9952–9960
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Trialkoxysilanes Inorganic nanoparticles Nanometric fillers Supercritical carbon dioxide
Résumé :	Trialkoxysilanes are widely used as primers to functionalize inorganic nanoparticles and to facilitate their interaction with organic phases. In this work, the silanization of nanometric fillers (titania and maghemite) was successfully carried out using supercritical carbon dioxide as the carrier solvent for octyltrialkoxysilane. First, the solubitility behavior of octyltriethoxysilane in compressed CO2 was evaluated at different pressures and temperatures. The measured solubility data were correlated using the Chrastil equation. Next, nanometric powders of either titania or maghemite were silanized at different pressures, temperatures, and reaction times. The prepared samples were characterized by electron microscopy, N2 adsorption−desorption, and laser scattering. Finally, the operating conditions that led to optimal material performance as a function of the intended application for the coated titanium dioxide powder (UV filter in cosmetics and filler in plastics) were evaluated by means of conveniently defined objective functions.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900775z

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9942–9951

Titre :	Rheology, morphology, mechanical properties and free volume of poly(trimethylene terephthalate)/polycarbonate blends
Type de document :	texte imprimé
Auteurs :	Indose Aravind, Auteur ; Kyung Hyun Ahn, Auteur ; C. Ranganathaiah, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9942–9951
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	poly(trimethylene terephthalate)/polycarbonate blends Rheological measurements
Résumé :	The phase morphology, rheology, mechanical properties, and free volume of poly(trimethylene terephthalate)/polycarbonate (PTT/PC) blends have been investigated as a function of composition. The morphology indicated a two-phase structure, and the blends showed co continuous phase morphology between 30−60 wt % of poly carbonate. Due to the high viscosity of PC, PTT is more finely dispersed in the PC matrix than PC in the PTT matrix. The rheological measurements of the blends revealed that the complex viscosity increased with increase in PC content. Relatively low interfacial tension values of the blends determined using Palierne and Choi−Schowalter methods indicated that there is considerable interaction between the blend components (PTT and PC) due to the transesterification reactions. A random copolyester formed as a result of the transesterification acted as a compatibilizer in the initial stages of reactions which is the main factor for the change in miscibility. The phase morphology and the interfacial adhesion influence the mechanical properties such that addition of the PC phase decreases the tensile strength and Young’s modulus of the system. The free volume data from PALS results showed a slight positive deviation from the known linear additivity rule with increase in PC content, suggesting the blends are partially miscible. Our results show a good correlation among the phase morphology, rheology, mechanical, and free volume parameters.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9007503

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9936–9941

Titre :	Enhancement of the meltdown temperature of a lithium ion battery separator via a nanocomposite coating
Type de document :	texte imprimé
Auteurs :	S. H. Yoo, Auteur ; C. K. Kim, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9936–9941
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Lithium ion battery separator Meltdown temperature
Résumé :	In a previous study, a lithium ion battery separator was coated with polymers synthesized from various ethylene glycol dimethacrylates to enhance its meltdown temperature. The meltdown temperature of the separator was increased to 155 °C when it was coated with polymer synthesized from diethylene glycol dimethacrylate (DEGDMA). In this study, a PE separator was coated with nanocomposites composed of DEGDMA polymer and silica nanoparticles for further enhancement of the meltdown temperature. Coatings with nanocomposites were prepared via two different methods: coating the separator by reacting a methanol solution containing DEGDMA and silica nanoparticles or coating the separator by reacting with a methanol solution containing water, DEGDMA, and tetraethylorthosilicate. The formation of nanocomposite on the separator was confirmed by FT-IR, EDS, and electron microscopy. Regardless of the coating method, an increase in the meltdown temperature with a decrease in the air permeability was observed with the nanocomposite coating. The meltdown temperature of the separator was increased to 170 °C with an acceptable reduction in the air permeability when the separator was coated with composite using the latter method.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901141u

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9930–9935

Titre :	Steam-generating composite sheets prepared using techniques in the papermaking process. 2. relationships between sheet structures and steam-generation behavior
Type de document :	texte imprimé
Auteurs :	Yoshiaki Kumamoto, Auteur ; Masataka Ishikawa, Auteur ; Hironobu Kawajiri, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9930–9935
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Sheet structures Steam-generation
Résumé :	Steam-generating sheets for disposable body warmers were prepared using techniques in papermaking processes, from slurries of iron powder, fibrillated cellulose fiber, and activated carbon powder with various weight ratios. Heat generation behavior of the composite sheets was compared with mat-formed samples. Composite sheets with the iron powder:cellulose fiber:activated carbon powder weight ratio of 86:6:8 had suitable heat generation temperatures in the range 40−42 °C and the longest duration time (>10 h), when exposed to air in the presence of 5% NaCl. On the basis of the results, a performance diagram relating the duration time at temperatures higher than 40 °C to the weight ratios of the three components was obtained. The steam-generation behavior of the composite sheets was superior to that of mat samples in terms of steam-generation rates, duration time, and other properties. After steam generation, the sheets became harder and stiffer than the original sheets through formation of fused iron oxide layers covering the sheet surfaces.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900876s

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9922–9929

Titre :	Steam-generating composite sheets prepared using techniques in the papermaking process. 1. effective retention of iron powder in a sheet using fibrillated cellulose fibers
Type de document :	texte imprimé
Auteurs :	Yoshiaki Kumamoto, Auteur ; Masataka Ishikawa, Auteur ; Hironobu Kawajiri, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9922–9929
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Flexible heat- and steam-generating sheets Iron powder
Résumé :	Flexible heat- and steam-generating sheets are promising medical devices for human healthcare, and oxidation of iron powder in sheets has potential applications for this purpose. Hence, the preparation conditions of composite sheets containing iron powder, cellulose fiber and activated carbon powder using techniques in the papermaking process were investigated to increase the iron powder content as much as possible and improve retention ratios of iron powder in the sheets. When unfibrillated cellulose fibers were used without any retention aids, the total retention ratios of the components were less than 40%. By contrast, when highly fibrillated cellulose fibers were used in combination with a cationic/anionic dual polymer system, the total retention ratios at a basis weight of 217 g m−2 reached about 90%. Moreover, iron powder aggregates in the sheet surfaces as well as throughout the thickness of the sheet, and higher tensile and internal strengths were obtained by using highly fibrillated cellulose fibers.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900875u

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9915–9921

Titre :	Degradation of methylene blue by heterogeneous fenton reaction using titanomagnetite at neutral pH values : process and affecting factors
Type de document :	texte imprimé
Auteurs :	Shijian Yang, Auteur ; Hongping He, Auteur ; Daqing Wu, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9915–9921
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Titanomagnetite Methylene blue
Résumé :	In this work, titanomagnetite was used as a heterogeneous Fenton catalyst for the degradation of methylene blue (MB). The degradation of MB on synthetic titanomagnetite at neutral pH values was studied in comparison with the adsorption of MB on titanomagnetite using UV−vis, FTIR, and the analyses of element C on titanomagnetite and DOC in reaction solution. Meanwhile, important factors affecting catalytic activity were investigated, that is, titanomagnetite load, H2O2 concentration, and reaction temperature. Titanomagnetite decomposed H2O2 yielding highly reactive hydroxyl radicals, and MB adsorbed on titanomagnetite was degraded. With the increases of titanomagnetite load, H2O2 concentration, and reaction temperature, the degradation of MB was promoted. Moreover, titanomagnetite was proved to be durable with a stable MB removal efficiency after five consecutive cycles.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900666b

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9910–9914

Titre :	Intrinsic kinetics of catalytic hydrogenation of cardanol
Type de document :	texte imprimé
Auteurs :	Zhi-Bo Mao, Auteur ; Ting-Liang Luo, Auteur ; Hong-Tao Cheng, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9910–9914
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Cardanol Catalytic hydrogenation Raney nickel catalyst
Résumé :	The experiment of catalytic hydrogenation of cardanol was performed on a Raney nickel catalyst for the purpose of eliminating the effects of internal and external diffusion. The kinetics data have been collected experimentally over ranges of 2.5−4 MPa and 373.15−393.15 K, respectively. Then, the intrinsic kinetics of the catalytic hydrogenation reaction of cardanol was studied. It was proven that the catalytic hydrogenation of cardanol is a second-order irreversible series-parallel reaction under the experimental conditions. The kinetic parameters (Ea, K0) and kinetic equation were obtained through fitting, and the kinetic model was proven through testing to be reliable.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900655a

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9902–9909

Titre :	Wet oxidation of thiocyanate under different pH conditions : kinetics and mechanistic analysis
Type de document :	texte imprimé
Auteurs :	Sergio Collado, Auteur ; Adriana Laca, Auteur ; Mario Díaz, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9902–9909
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Thiocyanate Wet oxidation
Résumé :	The wet oxidation of thiocyanate has been investigated in a 1-L semibatch reactor at temperatures in the range of 438.15−468.15 K and total pressures between 2.0 × 103 kPa and 8.1 × 103 kPa. The initial pH value of the reaction media was varied between pH 2 and pH 12 and was found to be a key parameter in the rate of thiocyanate degradation. The evolution of concentration of substrate and products (sulfate and ammonium) were analyzed. Based on the experimental data and bibliography information, a kinetic model was obtained and, here, possible pathways, depending on the initial pH of the media, are suggested for thiocyanate oxidation.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9006485

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9892–9901

Titre :	Kinetics of the acid digestion of serpentine with concurrent grinding. 2. detailed investigation and model development
Type de document :	texte imprimé
Auteurs :	Van Essendelft, Dirk T., Auteur ; Schobert, Harold H., Auteur
Année de publication :	2010
Article en page(s) :	pp. 9892–9901
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Magnesium Serpentine Mineral carbonation methodology
Résumé :	The rapid extraction of magnesium from serpentine is critical to novel low-pressure mineral carbonation methodology. Though almost any acid can dissolve the magnesium, the rate plays a critical role in the industrialization of the process. It has been demonstrated that including a low-energy, attrition-type grinding with the chemical attack of the acid can more than double the extraction rate. In part 1 of this investigation, it was found that a model that accounts for surface reaction, surface speciation, the electrical double layer, particle size distribution, and ash layer diffusion can adequately describe the kinetics of the dissolution of serpentine with concurrent grinding. However, the model did not account for changes in temperature, concentration, and grinding energy input. We report here the model developments and changes as well as a detailed experimental investigation to provide validation for the model.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9005832

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9885–9891

Titre :	Effect of magnesium addition to PtSnNa/ZSM-5 on the catalytic properties in the dehydrogenation of propane
Type de document :	texte imprimé
Auteurs :	Linyang Bai, Auteur ; Yuming Zhou, Auteur ; Yiwei Zhang, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9885–9891
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Magnesium addition Propane dehydrogenation
Résumé :	The effect of Mg addition to PtSnNa/ZSM-5 on the catalytic properties in propane dehydrogenation was investigated. The catalysts were characterized by using different techniques: XRD, BET, TEM, NH3-TPD, XPS, TPO, and TG-DTA. Results indicate that the presence of magnesium not only modifies the acid function and the structure of metallic phase but also diminishes carbon deposition on the catalyst. Among the catalysts studied, the PtSnNaMg(0.5%)/ZSM-5 exhibits the best performance in terms of propane conversion and stability. The high catalytic performance may be due to the strong interaction between Pt and Sn.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900534m

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9877–9884

Titre :	Kinetic characterization of xylose monomer and oligomer concentrations during dilute acid pretreatment of lignocellulosic biomass from forests and switchgrass
Type de document :	texte imprimé
Auteurs :	Juan E. Morinelly, Auteur ; Jill R. Jensen, Auteur ; Matthew Browne, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9877–9884
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Xylose monomer Kinetic model Oligomer concentrations
Résumé :	The kinetics of dilute acid hydrolysis for aspen, balsam, and switchgrass were investigated at various temperatures, acid concentrations, and reaction times using small-scale isothermal tubular reactors. The experimental data was fitted to a four-step kinetic model with first-order irreversible rate constants at each step. The maximum yields of xylose monomer for aspen and balsam show limited variability with changing reaction severity with maximum levels of approximately 85% and 67% of initial xylan, respectively. Switchgrass xylose monomer yields varied significantly with very low yields observed at 0.25 wt % acid (32% of initial xylan) and relatively high yields at 0.75 wt % acid (81% of initial xylan). The measured furfural levels at the point where xylose monomer is maximized, relative to initial xylan, range from 1% to 6% for aspen and balsam, and 3% to 15% for switchgrass. Excellent agreement, both quantitatively and qualitatively, is shown between the experimental monomer data and its model fit. Although the maximum xylose oligomer concentrations and the initial concentrations during oligomer formation are accurately predicted, the model with irreversible kinetic constants does not describe the oligomer data accurately at long times. The model predicts furfural levels comparable to those measured; however, the model overpredicts early data points and underpredicts late data points. Arrhenius kinetic parameters were derived for all three species at each step of the proposed model and these parameters were of the same order as literature values. Preliminary results in regards to the effect of aspen solids loading on reaction kinetics show that a 50% decrease in solids loading (10% to 5%) results in faster rates of reaction. This is particularly apparent for the degradation of xylose monomer which increases by a factor of almost 3. Several recommendations to improve the modeling of dilute acid hydrolysis reactions are discussed.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900793p

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9864–9876

Titre :	Energy efficiency in photocatalytic reactors for the full span of reaction times
Type de document :	texte imprimé
Auteurs :	Benito Serrano, Auteur ; Aaron Ortiz, Auteur ; Jesus Moreira, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9864–9876
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Photocatalytic reactors Kinetic modeling Parallel−series reaction network
Résumé :	OH• radicals react in photocatalytic reactors via adsorbed species on the catalytic surface through complex reaction mechanisms leading to complete mineralization of organic molecules. Our research group has recently contributed with kinetic modeling of the photocatalytic network using a parallel−series reaction network. This kinetic approach helps toward the assessment of the photocatalytic thermodynamic efficiency factors (PTEF) and quantum yields (QY). Efficiency calculations consider stoichiometric relationships involving observable chemical species and OH• groups. These stoichiometric equations set the OH• requirements for reaching a particular intermediate species and for the complete mineralization of them. On this basis, the PTEF and QY factors for phenol photoconversion point toward a high degree of photon utilization as in the case of Photo-CREC units and, as a result, confirm the value of photocatalysis for the conversion of organic pollutants in water.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900353n

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9858–9863

Titre :	Importance of biomass particle size in structural evolution and reactivity of char in steam gasification
Type de document :	texte imprimé
Auteurs :	Mohammad Asadullah, Auteur ; Shu Zhang, Auteur ; Zhenhua Min, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9858–9863
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Chars Combustion reactivity Alkali and alkaline earth metallic
Résumé :	An Australian mallee wood of different particle sizes was gasified in steam in a fluidized-bed reactor at different temperatures. The structural features of chars, combustion reactivity of chars, and alkali and alkaline earth metallic (AAEM) species retention in chars were investigated in view to elucidate how the particle size affects the carbon conversion during steam gasification of biomass. The structural features and combustion reactivity of chars were investigated using Raman spectroscopy and thermogravimetric anlysis, respectively. The Raman intensity and combustion reactivity of chars were seen to decrease with increasing temperature. However, the combustion reactivity of char increased with increasing biomass particle size in the bigger particle range (1.5−5.18 mm). This is due mainly to the increase of catalytic species (AAEM) retention in chars. The increased AAEM retention and condensation of aromatic ring systems are a result of increasing mass transfer resistance in bigger particles of biomass.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901214z

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9847–9857

Titre :	Adsorption and desorption of SOx on diesel oxidation catalysts
Type de document :	texte imprimé
Auteurs :	Oliver Krocher, Auteur ; Markus Widmer, Auteur ; Martin Elsener, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9847–9857
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	NO oxidation SO2Diesel oxidation catalysts
Résumé :	The deactivation of NO oxidation by SO2 was studied with the use of commercial diesel oxidation catalysts (DOC) and Pt/Al2O3 as reference material, coated on cordierite monolith. Despite their slightly different elemental compositions, the NO conversion rates of the fresh commercial catalysts were very similar. The maximum NO conversion was 38% at 350 °C, and above this temperature conversion started to be limited by the thermodynamics of the reaction. The rates of NO conversion strongly decreased with the start of SO2 dosing. For analysis of SO2 conversion and uptake, SO2 and SO3/H2SO4 were determined separately in the gas phase by absorption and titration. Under typical exhaust gas conditions (1 ppm SO2, 250 °C), the catalysts functioned as sulfur traps and stored a large part of the emitted SO2. The SOx storage was divided into two phases: a fast saturation of the catalyst surface with sulfuric acid, which hampered NO conversion, and a slow, long-lasting sulfation of the washcoat. The storage capacities of the oxidation catalysts reached their maxima at 250 °C due to the temperature dependency of sulfur adsorption and desorption. Adsorbed sulfuric acid desorbed between 350 and 400 °C, whereas more stable compounds, such as aluminum sulfate, were decomposed at higher temperatures. Deactivated catalysts could be completely regenerated within a few minutes at temperatures above 350 °C. However, repeated or lengthier thermal treatments resulted in a reduced sulfur storage capacity and irreversible activity losses for NO oxidation due to a reduction of the active surface by sintering.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900882p

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9837–9846

Titre :	Formation of tarry material from 5-HMF in subcritical and supercritical water
Type de document :	texte imprimé
Auteurs :	Athika Chuntanapum, Auteur ; Yukihiko Matsumura, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9837–9846
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Compound 5-hydroxymethylfurfural Biomass Tarry material
Résumé :	The compound 5-hydroxymethylfurfural (5-HMF) is thought to be an intermediate for the formation of tarry material in the supercritical water gasification (SCWG) of biomass. To gain insight on the formation mechanism of tarry material, we examined 5-HMF under both subcritical and supercritical conditions. The experiments of this study were conducted in a continuous reactor designed for an instant heating of 5-HMF solution to the reaction temperature. The reaction temperatures were set at 350 and 450 °C, and the pressure was set at 25 MPa. The initial concentration of 5-HMF and the residence time were adjusted in the range of 0.02−0.15 M (at room temperature) and 80−3000 s, respectively. The formation of char particles was only observed under the subcritical conditions. Char yield increased as the initial concentration of 5-HMF rose, with a reaction order of 4.29, with respect to 5-HMF concentration. The liquid products obtained from the 5-HMF decomposition also contributed to the polymerization to form char, with a reaction order of 1.21, based on their concentration. The sensitivity analysis indicated the high sensitivity of reaction orders on the char yield. The liquid products were identified by liquid chromatography/mass spectroscopy (LC/MS) and high-performance liquid chromatography (HPLC). The char particles were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, and Raman spectrometry. The char characterization results implied that the char particles formed had a polyaromatic structure. Based on our experimental findings, we proposed a mechanism of char particle formation from 5-HMF.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900423g

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9830–9836

Titre :	Bleaching miscanthus x giganteus acetosolv pulps with a new totally chlorine-free sequence and the effect of carbohydrate protectors
Type de document :	texte imprimé
Auteurs :	Juan Jose Villaverde, Auteur ; Pablo Ligero, Auteur ; Alberto De Vega, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9830–9836
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Semibleached Miscanthus x giganteus Acetosolv pulp Alkaline treatmentPeroxyacetate treatment
Résumé :	The bleaching of semibleached Miscanthus x giganteus Acetosolv pulp, after alkaline and peroxyacetate treatments, was investigated by a novel totally chlorine-free (TCF) sequence. Oxygen delignification (O-stage), peroxide (P-stage), and oxygen-pressurized hydrogen peroxide stage (PO-stage) were assayed in order to reach the target values for dissolving pulps. Using factorial experimental designs, we investigated the effects of the bleaching variables on the parameters defining the process and checked the effects after adding chelating agents. Regression equations satisfactorily fitted the experimental results, and under the optimum conditions, a fully bleached pulp (86.9% ISO brightness) with a viscosity of 786 cm3/g and a very favorable kappa number (1.3) was obtained. Carbohydrate protectors substantially improved the characteristics of dissolving pulps, but pulps with kappa values above 6 did not improve with carbohydrate protectors as expected.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9008277

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9823–9829

Titre :	Preparation of biomimetic materials made from polyaspartyl polymer and chitosan for heavy-metal removal
Type de document :	texte imprimé
Auteurs :	Bo Sun, Auteur ; Zhen-Tao Mi, Auteur ; Gang An, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9823–9829
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Polyaspartyl polymer Chitosan Peptide−polysaccharide-resembling structure
Résumé :	By the combination of polyaspartyl polymer and chitosan, a kind of novel environmentally friendly biomimetic blend material with peptide−polysaccharide-resembling structure was synthesized for heavy-metal removal. The resulting blend possesses diversified functional groups and was further modified by introducing a mercapto group through esterification between thioglycollic acid and hydroxyl group in the structure of chitosan. The polyaspartyl polymer−chitosan blend with 2.2 wt % mercapto group content improves the adsorption of organic compounds of mercury and arsenic. The blend exhibits a lower swelling behavior in the presence of water and is verified to have a potential biodegradability by elemental analysis and infrared spectrum (FT-IR).
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900673h

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9817–9822

Titre :	Modeling the effects of color on the UV protection provided by cotton woven fabrics dyed with azo dyestuffs
Type de document :	texte imprimé
Auteurs :	Ascensión Riva, Auteur ; Inés Algaba, Auteur ; Montserrat Pepio, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9817–9822
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Color UV radiation Ultraviolet protection factor
Résumé :	Color is one of the most influential variables on the protection against ultraviolet radiation provided by a fabric. The protection against UV radiation of a fabric is expressed quantitatively by means of its UPF (ultraviolet protection factor). The present paper shows the results of a study about the influence of the color on the UPF of cotton woven fabrics appropriate for summer articles. Through statistical models, the research seeks to relate the level of protection achieved in dyeing with three azo dyes to the factors governing the process, the shade, and the color intensity, as well as their interaction with the initial UPF of the fabrics. The obtained models will allow the programming and optimization of the value of the UPF of a fabric by means of adequate adjustment of the variables.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9006694

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9809–9816

Titre :	Thermochemistry of ionic liquid-catalyzed reactions : theoretical and experimental study of the beckmann rearrangement—kinetic or thermodynamic control?
Type de document :	texte imprimé
Auteurs :	Sergey P. Verevkin, Auteur ; Vladimir N. Emel'yanenko, Auteur ; Alexey V. Tkachev, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9809–9816
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Beckmann rearrangement reaction Kinetic control
Résumé :	A thermodynamic analysis of the experimental conditions of the Beckmann rearrangement reaction of oximes into amides has been undertaken to examine whether the reaction is under thermodynamic or kinetic control. To answer this question, the thermodynamic properties of the typical Beckmann rearrangement reactions in the ideal gaseous state—cyclohexanone oxime to caprolactam and 2-butanone oxime to N-methyl-propanamide—were studied by using the quantum mechanical method. Gibbs energy and equilibrium constants of the Beckmann rearrangement have been assessed in the gaseous and the liquid phases. Results of the thermodynamic analysis have shown that Beckmann rearrangements are kinetically controlled. Thus, a search for possible active ionic liquid based catalysts for the mild reaction conditions has been performed.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900633r

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9804–9808

Titre :	Adsorption of copper acetate onto pretreated activated carbons over a wide concentration range
Type de document :	texte imprimé
Auteurs :	Amjad Farooq, Auteur ; Philippe Westreich, Auteur ; Naseem Irfan, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9804–9808
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Copper acetate Microporous activated carbon
Résumé :	The commercially available microporous activated carbon Kuraray GC was pretreated in two different ways: one was heated to 950 °C in 5% hydrogen and the other boiled in nitric acid for 5 h. BET surface area measurements and Boehm titrations were done to find the surface area and the numbers of surface functional groups for each carbon. A large range of linearly varying concentrations of aqueous copper acetate solutions was made and stirred with each sample of pretreated carbon. Atomic absorption spectroscopy, titrations, and weight measurements were employed to measure the amount of copper acetate actually adsorbed onto the respective carbon samples. The number of acidic functional groups on the carbon surface as determined by Boehm titrations in the case of the hydrogen treated sample and the nitric acid treated sample do not match with the usual Langmuir parameters both at low and high concentrations. Two distinct isotherm fittings have been obtained for both carbons; double Langmuir isotherms for the hydrogen-treated sample, and a low concentration Langmuir isotherm combined with a high concentration Freundlich isotherm for the nitric acid treated sample. The results have also been compared with the results for untreated Kuraray GC.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900492f

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9797–9803

Titre :	Formation of highly hydrophobic surfaces on cotton and polyester fabrics using silica sol nanoparticles and nonfluorinated alkylsilane
Type de document :	texte imprimé
Auteurs :	Qinwen Gao, Auteur ; Quan Zhu, Auteur ; Yuliang Guo, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9797–9803
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Hydrophobic surfaces Textile fabrics
Résumé :	Water and soil repellency is one of the most desirable properties for textile fabrics. A surface with a water contact angle higher than 150° is considered to be a practically nonwettable superhydrophobic surface. In this research, we studied the formation of highly hydrophobic surfaces on cotton and polyester fabrics using silica sol formed by hydrolysis and subsequent condensation of tetraethoxysilane under alkaline conditions followed by hydrophobization using hydrolyzed hexadecyltrimethoxysilane (HDTMS). The textile fabrics thus treated showed excellent water repellency with a water contact angle as high as 155° on cotton and 143° on polyester. The high hydrophobicity of the treated fabrics is due to the presence of hydrophobic HDTMS as well as the increase in roughness by silica sol on the surfaces of the treated fabrics. The morphology of the cotton and polyester fabrics were characterized by scanning electron microscopy. We also found that the treated cotton and polyester are resistant to hydrolysis of multiple washing cycles.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9005518

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9786–9796

Titre :	Participation of electrochemical steps in treating tannery wastewater
Type de document :	texte imprimé
Auteurs :	C. Ahmed Basha, Auteur ; P. A. Soloman, Auteur ; M. Velan, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9786–9796
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Tannery wastewater Electrochemically treatement
Résumé :	The performance of conventional biological treatment of tannery wastewater can be improved by the application of electrochemical treatment to selected streams. In this study, soak liquor, tanning effluent, and post-tanning effluent were electrochemically treated in batch recirculation mode. The experiments were designed, modeled, and optimized using response surface methodology. Considerable removal of chemical oxygen demand (COD, 94.8%) was achieved by treating the soak liquor in a batch recirculation cell under conditions of a circulation flow of 142.8 L h−1, a current density of 5.8 A dm−2, and a time of 7.05 h. Salt remaining in the treated soak liquor was partly utilized in improving the ionic conductivity of the post-tanning effluent for electrochemical treatment. In a separate treatment, the biodegradability index of the post-tanning effluent was improved from 0.3 to 0.67 under conditions of a circulation flow of 112.5 L h−1, a current density of 2.4 A dm−2, and a time of 2.15 h. Considerable reduction in the requirement of reactor volume or residence time of the existing aerated biological treatment system of the total wastewater stream can be achieved by applying such an electrochemical pretreatment.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900464s

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9781–9785

Titre :	Novel carrier of grafted alginate for covalent immobilization of inulinase
Type de document :	texte imprimé
Auteurs :	Magdy M. M. Elnashar, Auteur ; Enas N. Danial, Auteur ; Ghada E. A. Awad, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9781–9785
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Grafted alginate FTIR techniques DSC techniques
Résumé :	Inulinase has been extracted from Penicillium chrysogenum P36 and immobilized on a novel matrix of grafted biopolymer. The crude enzyme has been characterized in terms of specific activity, optimum temperature, and temperature stabilities. A novel matrix of alginate modified with polyimines and cross-linked with glutaraldehyde was prepared in beads shape using the Encapsulator to covalently immobilize crude inulinase. The modified beads were characterized using the FTIR and the DSC techniques. The FTIR showed the presence of the aldehydic’s carbonyl group at 1670 cm−1, which differs from that of the carboxylic group at 1620 cm−1. The DSC revealed a significant improvement of the gel’s thermal stability from 200 to 240 °C. The immobilization process improved the enzyme’s optimum temperature from 50 to 55 °C as well as the enzyme’s thermal stability for 2 h at 60 °C with 78% retention of activity as compared to only 7% for the free enzyme. The enzyme’s optimum pH slightly shifted from pH 4.8 for the free enzyme to pH 5 for the immobilized enzyme. However, at pH 5.2−5.5, the enzyme activity improved from 39% for the free enzyme to 75% for the immobilized enzyme. The novel matrix successfully immobilized the inulinase covalently with an enzyme loading capacity of 461 U/g gel. The reusability test proved the durability of the grafted alginate for 20 cycles with retention of 95% of the immobilized enzyme activity, whereas the untreated alginate gel completely dissolved by the eighth use. The results were promising; the grafting method is simple, and immobilization efficiency and enzyme loading capacity could be further improved by optimizing the gel beads’ formulations and the conditions of immobilization for the industrial applications.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9011276

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9773–9780

Titre :	Coupling gliding discharge treatment and catalysis by oyster shell powder for pollution abatement of surface waters
Type de document :	texte imprimé
Auteurs :	Estella Njoyim, Auteur ; Paul Ghogomu, Auteur ; Samuel Laminsi, Auteur
Année de publication :	2010
Article en page(s) :	pp. 9773–9780
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Oyster shell powder Gliding electric discharge
Résumé :	Adsorption on oyster shell powder (OS) was combined with gliding electric discharge to abate pollution of surface waters sampled in brooks passing through large Cameroonian cities and collecting industrial and domestic wastes. OS powder incorporated into the aqueous samples after exposure to the discharge improved pollutant abatement as compared to the plasma treatment alone. The process kinetics involved pseudo zero-order reactions for treatments longer than 5 min. Total organic carbon linearly decreases with increasing exposure time to the discharge (k ≈ 0.13 mgC L−1 min−1 for a 1 g L−1 standard OS charge). The rate constant linearly increases with the incorporated OS mass, which increases the sample pH. The coupled process is more efficient than a single plasma treatment of the polluted liquid in terms of operation cost, waste abatement ratio, and reaction rate. A chemical model involving known plasma generated species and matching acid−base effects is proposed.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie901118m

Industrial & engineering chemistry research / Paul, Donald R. . Vol. 48 N° 22

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