Catalogue en ligne Bibliothèque Ecole Nationale Polytechnique d'Alger

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5558–5562

Titre :	Identification of sulfate and hydroxyl radicals in thermally activated persulfate
Type de document :	texte imprimé
Auteurs :	Chenju Liang, Auteur ; Hsin-Wey Su, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5558–5562
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Thermal activation Persulfate degradation Chemical probe method
Résumé :	Thermal activation can induce persulfate (S2O82−) degradation to form sulfate radicals (SO4−•) that can undergo radical interconversion to form hydroxyl radicals (HO•) under alkaline conditions. The radicals SO4−•/HO• can be present either individually or simultaneously in the persulfate oxidation system. To identify the active radical species, a chemical probe method was developed. An excess of probe compounds was added to the system, and differences between the reactivity of the probes and the potential radical species were observed. The usage of various probes, including tert-butyl alcohol, phenol, and nitrobenzene (NB), for simultaneously identifying SO4−•/HO• was investigated. NB can only react with radicals: it cannot react with persulfate. The reaction rate of NB with HO• is 3000−3900 times greater than that of NB with SO4−•, which is a good candidate for use as a probe for differentiating between SO4−•/HO• reactivity. Furthermore, the effects of pH on the formation of SO4−•/HO• were demonstrated by the degradation kinetics of NB at varying pH values. The results indicated that SO4−• is the predominant radical at pH <7; both SO4−• and HO• are present at pH 9; HO• is the predominant radical at a more basic pH (i.e., pH 12). The use of chemical probe NB is a suitable compound for differentiating HO•/SO4−• reactivity.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9002848

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5551–5557

Titre :	Simulation of the process for producing butanol from corn fermentation
Type de document :	texte imprimé
Auteurs :	Jiahong Liu, Auteur ; May Wu, Auteur ; Michael Wang, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5551–5557
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Butanol Ethanol corn Lifecycle assessment model GREET
Résumé :	This study focuses on the simulation of a complete process for producing butanol via acetone, butanol, and ethanol corn fermentation. The simulation, which begins with grain processing and proceeds through product purification, represents the first attempt to simulate such a complete process. Energy use for the production process is highlighted and compared to that for the conventional corn ethanol process. The simulation results are utilized in a lifecycle assessment for butanol as a potential transportation fuel. The lifecycle assessment study is conducted using the transportation full lifecycle assessment model, Greenhouse Gases, Regulated Emissions and Energy Use in Transportation (GREET), that has been developed by Argonne National Laboratory. A variety of key parameters are examined, such as the state of the art of the unit operations included in the process and their key process parameters, as well as their effects on the total energy consumption and greenhouse gas emissions in the lifecycle of butanol.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900274z

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5548–5550

Titre :	Clean production of acid blue 9 via catalytic oxidation in water
Type de document :	texte imprimé
Auteurs :	Junhua Wang, Auteur ; Honglin Wang, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5548–5550
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Acid Blue 9 Catalytic oxidation Iron phthalocyanine sulfonamide
Résumé :	A catalytic oxidation was developed for Acid Blue 9, with iron phthalocyanine sulfonamide (FePc(SO2NR2)4) as a catalyst and hydrogen peroxide as an oxidant. This reaction features mild conditions, an aqueous medium, and high yield. The reaction was successfully scaled up in a 3000-L reactor.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9000663

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5542–5547

Titre :	Comparison of two Ni-based oxygen carriers for chemical looping combustion of natural gas in 140 kW continuous looping operation
Type de document :	texte imprimé
Auteurs :	Philipp Kolbitsch, Auteur ; Johannes Bolhàr-Nordenkampf, Auteur ; Tobias Pröll, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5542–5547
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Ni-based oxygen carriers Natural gas Chemical looping combustion Fuel reactor
Résumé :	Two different Ni-based oxygen carriers (OCs) are applied to chemical looping combustion (CLC) of natural gas on a scale of 140 kW fuel power. Both OCs are composed of NiO and a support material which is NiAl2O4 in the case of OC-A and a mixture of NiAl2O4 and MgAl2O4 in the case of OC-B. Fuel reactor temperature and global air/fuel ratio variations are performed and indicate the high reactivity of both OCs. Solids sampling during operation allows the determination of the oxidation degree of the particles in the air and fuel reactors. In general, both OCs show a low degree of oxidation during operation. Despite very low H2O/CH4 molar ratios in the fuel reactor, no carbon formation is observed under any conditions. In reforming conditions (global air/fuel ratio < 1), a complete uptake of the available O2 is observed in the air reactor.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900123v

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5537–5541

Titre :	Weighted-power-mean mixture model for the gibbs energy of fluid mixtures
Type de document :	texte imprimé
Auteurs :	Walter W. Focke, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5537–5541
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Gibbs energy Cubic equations of state
Résumé :	A continuous family of excess Gibbs free energy expressions is derived based on the double-weighted power mean mixture model and concepts from cubic equations of state. This family has two types of parameters: The model form is determined by two power indices, whereas the matrix of binary coefficients characterizes pure component behavior and binary interactions. It is shown that the Porter, Margules, and Wassiljewa composition dependence are but special forms of this more general expression. In particular, the Wassiljewa Gibbs free energy form turns out to have the same composition dependence as the nonrandom two-liquid (NRTL) equation.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900083h

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5530–5536

Titre :	Thermodynamic modeling of the aqueous solubility of PAHs
Type de document :	texte imprimé
Auteurs :	Mariana B. Oliveira, Auteur ; Vera L. Oliveira, Auteur ; João A.P. Coutinho, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5530–5536
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Polycyclic aromatic hydrocarbons Aqueous solubilities CPA EoS
Résumé :	Polycyclic aromatic hydrocarbons (PAHs) are a family of compounds characterized by having two or more condensed aromatic rings. They are important environmental contaminants associated with oil spills and the incomplete combustion of organic materials. Different models are available in the literature for estimating the aqueous solubilities of organic compounds, but the most accurate are frequently based on the correlation of experimental data, which hampers their use as predictive tools. In this work, the cubic-plus-association equation of state (CPA EoS) is shown to be an accurate model for describing the aqueous solubilities of several solid PAHs in wide temperature and pressure ranges. The results obtained are in very close agreement with the literature data, even when the model is used in a totally predictive scheme. Following previous results on the aqueous solubilities of other organic pollutants, the use of the CPA EoS for describing the aqueous solubilities of organic pollutants such as polycyclic aromatic hydrocarbons is suggested.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900011g

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5522–5529

Titre :	Symmetric nonrandom two-liquid segment activity coefficient model for electrolytes
Type de document :	texte imprimé
Auteurs :	Yuhua Song, Auteur ; Chau-Chyun Chen, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5522–5529
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	NRTL-SAC Correlation Predicting phase Electrolyte model
Résumé :	The nonrandom two-liquid segment activity coefficient model (NRTL-SAC) [Chen, C.-C.; Song, Y. Solubility Modeling with a Nonrandom Two-Liquid Segment Activity Coefficient Model. Ind. Eng. Chem. Res. 2004, 43, 8354−8362] has been shown to be a simple and practical thermodynamic model for correlating and predicting phase behavior for complex pharmaceutical molecules. The model was later extended for electrolytes [Chen, C.-C.; Song, Y. Extension of Non-Random Two-Liquid Segment Activity Coefficient Model for Electrolytes. Ind. Eng. Chem. Res. 2005, 44, 8909−8921]. However, the electrolyte model was presented as an unsymmetric activity coefficient model with aqueous phase infinite dilution reference state. Such an unsymmetric model becomes rather cumbersome to use when dealing with nonaqueous solvents. In this work, we present a symmetric electrolyte NRTL-SAC model which simplifies the long-range interaction term. We further examine the utility of the model in predicting salt solubilities in nonaqueous solvents and mixed solvents.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900006g

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5506–5521

Titre :	Logical and generalized disjunctive programming for supplier and contract selection under provision uncertainty
Type de document :	texte imprimé
Auteurs :	Maria Analia Rodriguez, Auteur ; Aldo Vecchietti, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5506–5521
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Supply-chain Uncertainty
Résumé :	Supply-chain optimization is a key issue in gainnig competitiveness in today’s economies where buyers and suppliers develop long-term relationships. Final agreements are formalized by signing contracts involving the purchasing of large amounts of materials, taking advantage of economies of scale. Although establishing agreements with suppliers is definitely an important step in reducing uncertainty, uncertainty never completely disappears. For that reason, the problem addressed in this article is the delivery and purchase optimization in a supply chain under provision uncertainty. Several decisions are presented in this problem that can naturally be posed in terms of of discrete decision models and generalized disjunctive programming. Uncertainty is modeled through a new approach that avoids the drawbacks of traditional methods. The goal pursued in this article is to contribute to better raw-material usage and tactical decisions to face an uncertain provision process in the supply chain.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801614x

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5498–5505

Titre :	Thermodynamic modeling of several aqueous alkanol solutions containing amino acids with the perturbed-chain statistical associated fluid theory equation of state
Type de document :	texte imprimé
Auteurs :	Luísa A. Ferreira, Auteur ; Martin P. Breil, Auteur ; Simao P. Pinho, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5498–5505
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	EoS Amino acids Aqueous solutions Solubility
Résumé :	The perturbed-chain statistical associated fluid theory EoS was applied to model the solubilities of glycine, dl-alanine, l-serine, l-threonine, and l-isoleucine in pure water, pure alcohols (ethanol, 1-propanol, and 2-propanol) and in mixed solvent systems. Three pure component nonassociating parameters for the amino acids were fitted to the densities, activity and osmotic coefficients, vapor pressures, and water activity of their aqueous solutions. The solubilities of amino acids in pure and mixed solvent systems were calculated on the basis of the phase equilibrium conditions for a pure solid and a fluid phase. The hypothetical melting properties of each amino acid were fitted, to accurately correlate the solubilities in pure water. Only one temperature independent binary parameter is required for each amino acid/solvent pair. The model can accurately describe the solubility of the amino acids in water, but the correlation for the solubility in pure alcohols was not so satisfactory. The solubility in mixed solvents (ternary systems) was predicted on the basis of the modeling of the solubility in pure solvents, without any additional fitting of the parameters, and the results achieved were reasonable. Fitting the binary parameter for the pair amino acid/alcohol not to the solubility in pure alcohol, but to the solubility in the mixed solvent system, the description of the solubility in the mixed solvent systems was clearly improved and the results were in fair agreement with the experimental data for all mixture compositions. The results showed a global root-mean-square deviation in mole fraction of 0.0032 for correlation and 0.0070 for prediction.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801567w

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5489–5497

Titre :	Incremental global parameter estimation in dynamical systems
Type de document :	texte imprimé
Auteurs :	Michalik, Claas, Auteur ; Benoît Chachuat, Auteur ; Marquardt, Wolfgang, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5489–5497
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Dynamical system Efficient computational method Software packages Incremental identification
Résumé :	Estimating the parameters of a dynamical system based on measurements is an important task in industrial and scientific practice. Since a model’s quality is directly linked to its parameter values, obtaining globally rather than locally optimal values is especially important in this context. In practice, however, local methods are used almost exclusively. This is mainly due to the high computational cost of global dynamic parameter estimation, which limits its application to relatively small problems comprising no more than a few equations and parameters. In addition, there is still a lack of software packages that allow global parameter estimation in dynamical systems without expert knowledge. Therefore, we propose an efficient computational method for obtaining globally optimal parameter estimates of dynamical systems using well-established, user-friendly software packages. The method is based on the so-called incremental identification procedure, in combination with deterministic global optimization tools for nonlinear programs.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8015472

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5481–5488

Titre :	Effect of sampling line characteristics on the dynamic monitoring of fluid concentrations
Type de document :	texte imprimé
Auteurs :	Harpreet S. Juneja, Auteur ; Junpin Yao, Auteur ; Farhang Shadman, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5481–5488
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Sampling line Fluid concentrations Dynamic monitoring
Résumé :	A novel approach is developed and demonstrated to characterize the sampling line effects during dynamic monitoring of fluid concentrations. The “sampling line” in this study refers to all components between the point of fluid sampling and the point of analyzer sensor. In general, sampling lines introduce errors in measurements by altering the sample properties due to the fluid transport in the line as well as the adsorption and desorption of fluid constituents on the surfaces of the sampling components that come into contact with the sample fluid. A methodology based on a sampling line simulator is developed for taking these effects into account and correcting the measurements. The model is validated by direct experimental measurements using several different analyzers under various conditions. The sampling line simulator can be used to analyze the effect of various sampling configurations and operating conditions; this would be helpful in the design of sampling lines and their location. An algorithm is proposed that can be used to convert concentration values measured and reported by the analyzer to the concentration values at the point of sampling that are the actual and desired values.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8016169

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5472–5480

Titre :	Thermodynamics of triethylene glycol and tetraethylene glycol containing systems described by the cubic-plus-association equation of state
Type de document :	texte imprimé
Auteurs :	Martin P. Breil, Auteur ; Georgios M. Kontogeorgis, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5472–5480
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Triethylene glycol Vapor pressure data Liquid density data Liquid-liquid equilibria data Binary systems
Résumé :	A thorough investigation of triethylene glycol (TEG) containing systems has been performed. The introduction of a new six-site association scheme for the TEG molecule has shown to be advantageous. Glycols are often modeled using a four-site scheme (abbreviated as 4C) hence ignoring the internal lone pairs of oxygen. The new association scheme also takes these sites into account. The new parameters of TEG are based on the vapor pressure data, liquid density data, and liquid−liquid equilibria (LLE) data (n-heptane), and they are tested for binary systems (methane, n-octane, n-nonane, n-decane, benzene, toluene, ethylbenzene, and water) and different types of phase equilibria (vapor−liquid equilibria (VLE) and LLE) and thermodynamic properties (heat of mixing, activity coefficients). A less extensive investigation has also been performed on tetraethylene glycol (TeEG) containing systems. Similarly, a new seven-site association scheme for the TeEG molecule has been investigated. The new parameters of TeEG are based on vapor pressure data, liquid density data, and LLE data (n-heptane). The performance is similar to that the 4C scheme.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801412y

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5460–5471

Titre :	Shear viscosity of CO2-plasticized polystyrene under high static pressures
Type de document :	texte imprimé
Auteurs :	Maxwell J. Wingert, Auteur ; Shunahshep Shukla, Auteur ; Kurt W. Koelling, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5460–5471
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Shear viscosity measurements Polymer/supercritical fluid systems Pressure
Résumé :	High-pressure shear viscosity measurements of polymer/supercritical fluid systems are numerous, but most involve pressure-gradient equipment such as a capillary or slit die with pressure drops exceeding 10%. Pressure change across the measurement region introduces some errors when quantifying the effect of blowing agents and other diluents on viscosity. This source of errors was removed by using a static-pressure, Couette rheometer. The viscosity of polystyrene (PS)/carbon dioxide (CO2) was measured from 140 to 180 °C and from 3 to 6 wt % CO2. The effect of pressure on diluent-free PS viscosity was required to calculate the CO2 concentration shift factor. Thus, viscosities at both atmospheric and elevated pressure (via helium, an insoluble gas) were measured using the same equipment and method. The Fillers−Moonan−Tschoegl (FMT) model was overdefined for obtaining free volume parameters, but it was a helpful correlation tool to obtain the pressure effect on viscosity. Pressure and concentration shift factors obtained from the experiments were compared with empirical free-volume plasticization models, one based on glass transition temperature, the other on P−V−T behavior. Unfortunately, neither model demonstrated quantitative agreement with the experimental data within the 3−6 wt % CO2 range examined. The WLF−Chow model, based on Tg data, fared better than the P−V−T-based model.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800896r

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5454–5459

Titre :	Calcium oxide doped sorbents for CO2 uptake in the presence of SO2 at high temperatures
Type de document :	texte imprimé
Auteurs :	Hong Lu, Auteur ; Panagiotis G. Smirniotis, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5454–5459
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Carbon dioxide Sorbent tolerance Sulfur dioxide Calcium oxide sorbent Dopants
Résumé :	There is an urgent need to understand sorbent tolerance for capturing carbon dioxide (CO2) in the presence of sulfur dioxide (SO2). Sulfur oxide is emitted together with CO2 from various combustion systems and can cause severe air pollution. In this study, the behavior of different dopants on the performance of calcium oxide (CaO) sorbent for capturing CO2 in the presence of SO2 was investigated. Three main sets of experiments were carried out to study carbonation and sulfation both separately and simultaneously using a thermogravimetric analyzer (TGA). The results show that SO2 reduced the capability of the sorbents for capturing CO2 because of the competition between carbonation and sulfation reactions. Formation of calcium carbonate (CaCO3) and calcium sulfate (CaSO4) took place upon carbonation and sulfation, respectively. Our TGA and X-ray photoelectron spectroscopy (XPS) results indicate that the carbonation is totally reversible, while this is not the case with the sulfation. The permanent residual weight gained by the sorbents during the course of sulfation is attributed to the irreversible formation of sulfate species, which is confirmed by both the TGA and XPS results. The Ce promoted CaO sorbent exhibits the best performance for CO2 capture and is the most SO2 tolerant sorbent. On the other hand, the Mn doped dopant has the strongest affinity for SO2.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900162k

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5445–5453

Titre :	Evaluation of the adsorption of aquatic humic substances in batch and column experiments by thermally modified activated carbons
Type de document :	texte imprimé
Auteurs :	Unai Iriarte-Velasco, Auteur ; Jon I. Álvarez-Uriarte, Auteur ; Noemí Chimeno-Alanís, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5445–5453
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Granular activated carbons Batch Column mode experiments Aquatic humic substances
Résumé :	Two commercially available granular activated carbons (GACs) were thermally modified and evaluated for their adsorption properties in batch and column mode experiments. The widely used and well characterized aquatic humic substances were used as adsorbate. The aim was to relate the adsorption properties of GAC with their physicochemical properties and also evaluate the impact of heat treatment under nitrogen atmosphere on the performance of the adsorbent in both batch and column operation modes. Heat treatment had a qualitatively similar effect on surface basicity and pore volume of both adsorbents. However, in quantitative terms, significant differences were reported. Heat-treatment enhanced batch adsorption capacity only for GAC-A. Surface available in pores within 12−15 Å width was strongly correlated to the NOM adsorption capacity. Benefits of thermal treatment were more evident at high initial solute concentrations. Results from batch adsorption did not have a straightforward relationship with column adsorption performance. Column adsorption capacities at complete breakthrough reached 26% and 79% of batch mode capacities. The highest difference was observed for carbon GAC-A, which corresponds to the more mass transfer limited system. During column operation smaller fractions of NOM were more readily adsorbed compared to batch mode.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900053p

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5439–5444

Titre :	Oxygen separation from air by four-bed pressure swing adsorption
Type de document :	texte imprimé
Auteurs :	Masoud Mofarahi, Auteur ; Jafar Towfighi, Auteur ; Leila Fathi, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5439–5444
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Pressure swing adsorption Zeolite 5A Oxygen separation
Résumé :	A study on a four-bed seven-step pressure swing adsorption (PSA) using zeolite 5A was performed experimentally and theoretically for separation of oxygen from air. In this process the steps of feed pressurization, production, blowdown, purge, pressure equalization (two steps), and product pressurization are included in a cycle. The effects of various operating parameters such as adsorption pressure, cycle time, production rate, and purge rate on the product purity and recovery were investigated experimentally. Oxygen purity and recovery both increase when adsorption pressure increases. For most of the experiments at the highest purge rate, a higher purity of oxygen is obtained, but the recovery of oxygen is reduced. Oxygen recovery increases as production rate increases while the purge flow rate remains constant. It was observed that increasing the cycle time increases the performance of the process. An equilibrium based isothermal model in conjunction with an LDF (linear driving force) approximation was employed to simulate process performance. Comparison of the results obtained from the experiments and simulation results shows reasonable agreement.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801805k

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5431–5438

Titre :	Separation of oxygen isotopic water by using a pressure-driven air gap membrane distillation
Type de document :	texte imprimé
Auteurs :	Jaewoo Kim, Auteur ; Dae-Shik Chang, Auteur ; Yun-Young Choi, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5431–5438
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Oxygen isotopic water Air gap membrane distillation Multistage MD system Pressure-driven AGMD
Résumé :	Separation of oxygen isotopic water using a newly developed pressure-driven air gap membrane distillation (AGMD) process that is applicable to a multistage MD system was investigated. Pressure-driven (PD) AGMD is distinguished from a currently available AGMD by way of its permeation flux generation. It uses a peristaltic pump to generate the pressure gradient on the membrane interface. Permeation characteristics and isotopic selectivity of four different hydrophobic membranes were evaluated. Permeation fluxes under the various conditions were measured by weighing the collected membrane-permeated water. Permeation fluxes for PD AGMD were higher than those of AGMD as much as 4.2-fold whereas the degree of isotope selectivity was competitive. The oxygen isotopic concentrations of the samples were analyzed by measuring the isotopic ratio H218O/H216O using tunable diode laser absorption spectroscopy and isotopic ratio mass spectrometer. A multistage PD AGMD system was also successfully constructed and operated.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900277r

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5427–5430

Titre :	Entrainer screening for separation of isoparaffins and naphthenes by extractive distillation
Type de document :	texte imprimé
Auteurs :	Sifang Li, Auteur ; Hai Liu, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5427–5430
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Entrainer screening Isoparaffins Naphthenes Extractive distillation
Résumé :	In the entrainer screening for separation of isoparaffins and naphthenes (C9−C14) by extractive distillation of D60 oil, various single entrainers and mixed entrainers were used and studied. Sulfolane was the most selective entrainer as a single entrainer was applied and the relative volatility of isoparaffins to naphthenes reached 1.648 as the sulfolane to oil ratio was 5:1. Both mixed entrainers of sulfolane + triethylene glycol and sulfolane + dimethyl phthalate show good synergistic effect, whereas a mixed entrainer of triethylene glycol and dimethyl phthalate shows little synergistic effect. The most selective mixed entrainer was a mixture of 50 vol % of sulfolane and 50 vol % of dimethyl phthalate, the relative volatility of isoparaffins to naphthenes reached 1.835. Results from the experiment in an extractive distillation column show that isoparaffins concentration of more than 95 wt % in the isoparaffins product and naphthenes concentration of more than 94 wt % in the naphthenes product are achieved.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900267m

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5420–5426

Titre :	Development of a new process for palm oil refining based on supercritical fluid extraction technology
Type de document :	texte imprimé
Auteurs :	Zainuddin A. Manan, Auteur ; Lim C. Siang, Auteur ; Ana N. Mustapa, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5420–5426
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Palm oil refining Supercritical fluid extraction technology Crude palm oil-supercritical CO2 mixture Flowsheet structure
Résumé :	This work describes the conceptual development of a new process for palm oil refining using supercritical fluid extraction (SFE) technology. The first step was to model the phase equilibrium behavior of a crude palm oil (CPO)−supercritical CO2 mixture. Next, a new flowsheet structure was synthesized to recover high-purity palm oil and its minor components. The new SFE process was finally simulated using Aspen Plus commercial process simulator version 10.2.1 based on the Redlich−Kwong−Aspen (RKA) thermodynamic model. The results obtained were in good agreement with the pilot plant data reported in the literature. It is envisioned that the development of a new, intensified palm oil refining process that is based on SFE technology can make the refining process drastically simpler and overcome the limitations of the existing technology for palm oil refining.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801735y

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5415–5419

Titre :	Effect of hydrocarbons on the separation of carbon dioxide from methane through a polyimide gas separation membrane
Type de document :	texte imprimé
Auteurs :	Raza Hasan, Auteur ; Colin A. Scholes, Auteur ; Geoff W. Stevens, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5415–5419
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Carbon dioxide Membrane gas separation Polymeric membrane
Résumé :	The removal of carbon dioxide from natural gas by membrane gas separation is an important process in upgrading the gas for consumers. Hydrocarbons associated with natural gas have the potential to influence the CO2 separation performance of membranes. Here, a glassy polymeric membrane of poly (4,4′-hexafluoroisopropylidene diphthalic anhydride-2,3,5,6-tetramethyl-1,4-phenylenediamine) (6FDA-TMPDA) was exposed to hexane and toluene at different partial pressures in a 90% CH4−10% CO2 gas mixture. The permeability of CO2 and CH4, as well as the selectivity, declined over time as both hexane and toluene competitively sorbed into the membrane. The resulting behavior fit the dual-sorption model for polymeric membrane separation and indicated Langmuir affinity constants of 0.13 ± 0.03 atm−1 for methane, 240 ± 100 atm−1 for hexane, and 980 ± 500 atm−1 for toluene (fugacity basis). The kinetics of the permeability decline were faster than that of the permeability recovery after the hydrocarbon contaminant was removed which may indicate that desorption from the Langmuir voids is the rate controlling step.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801537g

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5406–5414

Titre :	Continuous supercritical CO2 process using nanofiltration by inorganic membrane
Type de document :	texte imprimé
Auteurs :	Moonsung Koh, Auteur ; Bruno Fournel, Auteur ; Stephane Sarrade, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5406–5414
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Inorganic membranes Nanofiltration Supercritical CO2
Résumé :	Nanofiltration using inorganic membranes was conducted to develop a continuous process in supercritical CO2. Inorganic membranes of various sizes (1, 5, 50, 300 kDa), materials (Al2O3/TiO2/ZrO2, Al2O3/ZrO2/TiO2), and modules (one and three channels) were used for the experiments. The effects of fluid viscosity and density, membrane active layer thickness, number of channels, pore size, and the flux of a fluid were analyzed when supercritical CO2 (sc-CO2) passed through the membrane. In the case of PE6100 surfactant, it was confirmed that sc-CO2 passed through the membrane at a flow rate and transmembrane pressure (ΔP) greater than 10 mL/min and 0.04 MPa, respectively, although the size of the surfactant was larger than that of the membrane pore. The phenomena were proven to have been caused by the folding effect. In the case of microemulsions using NP-4 and H2O, it was confirmed that water adsorbed on the membrane surface passed through at ΔP greater than 0.7 MPa. Based on these findings, experiments were conducted to separate microemulsions and dispersions. The experimental results indicated that microemulsions achieved 47% separation efficiency and 90% surfactant recovery efficiency due to the displacement of metal ions through the water adsorbed on the membrane surface. Conversely, dispersions yielded high separation efficiency. Also, the correlation between the contaminant size and the membrane pore size was confirmed through SEM images.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800452g

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5399–5405

Titre :	Model predictive control of a wet limestone flue gas desulfurization pilot plant
Type de document :	texte imprimé
Auteurs :	A. L. Villanueva Perales, Auteur ; P. Ollero, Auteur ; F. J. Gutiérrez Ortiz, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5399–5405
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Model predictive control Dynamic matrix Wet limestone flue gas desulfurization
Résumé :	A model predictive control (MPC) strategy based on a dynamic matrix (DMC) is designed and applied to a wet limestone flue gas desulfurization (WLFGD) pilot plant to evaluate what enhancement in control performance can be achieved with respect to a conventional decentralized feedback control strategy. The results reveal that MPC can significantly improve both reference tracking and disturbance rejection. For disturbance rejection, the main control objective in WLFGD plants, selection of tuning parameters and sample time, is of paramount importance due to the fast effect of the main disturbance (inlet SO2 load to the absorber) on the most important controlled variable (outlet flue gas SO2 concentration). The proposed MPC strategy can be easily applied to full-scale WLFGD plants.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801530x

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5388–5398

Titre :	Optimization of multibed pressure swing adsorption processes
Type de document :	texte imprimé
Auteurs :	Dragan Nikolic, Auteur ; Eustathios S. Kikkinides, Auteur ; Georgiadis, Michael C., Auteur
Année de publication :	2009
Article en page(s) :	pp. 5388–5398
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Pressure swing adsorption Multibed configurations Multilayered adsorbents
Résumé :	This work presents an optimization framework for complex pressure swing adsorption (PSA) processes including multibed configurations and multilayered adsorbents. The number of beds, PSA cycle configuration, and various operating and design parameters have been systematically optimized using recent advances on process optimization. The Unibed principle has been adopted relying on the simulation over times of only one bed while storage buffers have been used to model bed interactions. A novel state transition network (STN) representation is employed for the efficient simulation and optimization of the processes. Two large-scale multicomponent separation processes have been used to illustrate the applicability and potential of the proposed approach in terms of improvement of product purity and recovery. Results indicate that significant improvements can be achieved over base case designs.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801357a

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5379–5387

Titre :	Data-driven soft sensor design with multiple-rate sampled data : a comparative study
Type de document :	texte imprimé
Auteurs :	Bao, Lin, Auteur ; Bodil Recke, Auteur ; Torben M. Schmidt, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5379–5387
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Multirate systems Samples Numerical interpolation Polynomial transformation Data lifting Weighted partial least squares
Résumé :	Multirate systems are common in industrial processes where quality measurements have slower sampling rates than other process variables. Since intersample information is desirable for effective quality control, different approaches have been reported to estimate the quality between samples, including the numerical interpolation, polynomial transformation, data lifting, and weighted partial least squares (WPLS). Two modifications to the original data lifting approach are proposed in this paper: reformulating the extraction of a fast model as an optimization problem and ensuring the desired model properties through Tikhonov Regularization. A comparative investigation of the four approaches is performed. Their applicability, accuracy, and robustness to process noise are evaluated with a single-input single-output (SISO) system. The modified data lifting and WPLS approaches are implemented to design quality soft sensors for cement kiln processes using data collected from a simulator and a plant log system. Preliminary results reveal that the WPLS approach is able to provide accurate one-step-ahead prediction. The regularized data lifting technique predicts the product quality of cement kiln systems reasonably well, demonstrating the potential to be used for effective quality control and as an advanced component of process analytical technology (PAT).
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801084e

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5370–5378

Titre :	Design and economic analysis of the process for biodiesel fuel production from transesterificated rapeseed oil using supercritical methanol
Type de document :	texte imprimé
Auteurs :	Youngsub Lim, Auteur ; Hong-shik Lee, Auteur ; Youn Woo Lee, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5370–5378
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Biodiesel fuel production Alkali-catalyzed process Supercritical biodiesel process
Résumé :	A supercritical process for biodiesel fuel production is generally known to be less profitable than the alkali-catalyzed process due to high temperature and pressure requirements for the supercritical reaction. Only a few approaches have been proposed using experimental results to design a supercritical biodiesel process and to assess its profitability compared to the alkali-catalyzed process. In this study, a design for a supercritical biodiesel process was suggested and its economic performance with three different reaction conditions was simulated in the comparison with the conventional alkali-catalyzed process. It was found that the total capital cost was higher in all three cases of the supercritical process than in the alkali-catalyzed process due to the high cost of pumps, heaters, and heat exchangers. However, the total manufacturing cost of the supercritical process was lower than that of the alkali-catalyzed process due to the higher glycerol credit and the lack of a requirement for catalyst or solvent. The supercritical process can produce high-purity glycerol more easily that does not contain any water, which is unavoidable in the washing step of the alkali-catalyzed process. The higher steam cost in the supercritical process was compensated for by catalyst and solvent costs in the alkali-catalyzed process. Overall, one of the supercritical processes resulted in shorter payout time than the alkali-catalyzed process even when virgin oil was used as one of the raw materials, because the lower total manufacturing cost made up for the increased total capital cost.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8005287

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5360–5369

Titre :	Characterization and dynamic optimization of membrane-assisted crystallization of adipic acid
Type de document :	texte imprimé
Auteurs :	Jelan Kuhn, Auteur ; Richard Lakerveld, Auteur ; Herman J. M. Kramer, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5360–5369
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Membrane-assisted crystallization Reverse osmosis (MaC-RO) Aqueous adipic acid solution
Résumé :	The concept of membrane-assisted crystallization using reverse osmosis (MaC-RO) shows a high potential in decreasing energy conversion as compared to evaporative crystallization. A setup has been constructed for MaC-RO, using two separate loops for membrane separation and crystallization. In this study we focus on the characterization of the membrane performance in solvent removal from an aqueous adipic acid solution under reverse osmosis conditions. A semiempirical model was developed for the flux as a function of temperature, concentration, and pressure difference across the membrane. The presence of adipic acid strongly reduces the flux at the same feed temperature and pressure, as compared to the flux from a pure water feed. This effect could be attributed to competitive adsorption on the membrane surface and, to a lesser extent, concentration polarization. For a batch MaC-RO process a dynamic optimization was conducted by changing the operational policy (membrane feed pressure, flow rate, and temperature). The energy conversion is minimized while maintaining a high, prior optimized product yield, defined as the volume-based mean size. The so-determined optimal operational policy results in a six times lower energy conversion as compared to evaporative crystallization with a final mean size that closely corresponds to the maximum mean size that can be achieved in a crystallizer with ideal control of supersaturation. This study demonstrates the potential of the concept of MaC-RO in terms of control over product quality and reduction of energy conversion.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie802010z

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5351–5359

Titre :	Simulation of methanol production from biomass gasification in interconnected fluidized beds
Type de document :	texte imprimé
Auteurs :	Yanan Zhang, Auteur ; Jun Xiao, Auteur ; Laihong Shen, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5351–5359
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Methanol synthesis Biomass gasification Fluidized beds CaCO3 catalysis
Résumé :	Simulation of methanol synthesis via H2-rich biomass-derived syngas from biomass gasification in interconnected fluidized beds is carried out, using Aspen Plus software to establish this model. In the case of CaCO3 catalysis, the effects of operating parameters, including gasification temperature and pressure, steam /biomass ratio (S/B), and liquefaction temperature and pressure, on the methanol yield are analyzed. The results are as follows: In the case of CaCO3 catalysis, biomass steam gasification can obtain 82.13% hydrogen-rich gas and when the Cu-based catalyst in China which is composed of 58.1% CuO + 30.06% Al2O3 + 31.7% ZnO + 4.0% H2O is adopted as the methanol synthesis catalyst; the gasification temperature is suggested to be controlled at about 750 °C in the interconnected fluidized beds biomass gasification system with the purpose of methanol production. Furthermore, the gasification pressure is proposed to approach to the ambient pressure and the S/B ratio of 0.4−0.5 operates better. On the optimal operating condition, the maximum of 12.19 mol/(kg biomass (daf)) of methanol yield may be obtained. The research provides useful results for the further study of biomass gasification and methanol synthesis from biomass syngas.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801983z

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5344–5350

Titre :	Assessment of the integral resource consumption of individual chemical production processes in a multipurpose pharmaceutical production plant : a complex task
Type de document :	texte imprimé
Auteurs :	Geert Van der Vorst, Auteur ; Jo Dewulf, Auteur ; Wim Aelterman, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5344–5350
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Integral resource consumption Multipurpose plants Integral mass Energy balances
Résumé :	Up to now, process specific integral resource consumption is barely used as criterion for the selection and improvement of fine chemical and pharmaceutical production processes. Reasons are the complexity of the supply networks in multipurpose plants and the requirement of a detailed data inventory from the production plant itself and from facilities delivering supporting utilities and treating waste streams. In this paper, a methodology is presented to set up integral mass and energy balances of specific production processes in the pharmaceutical and fine chemical industry. This methodology is based on the principle that each chemical production process is a sequence of unit operations in which basic operations at individual equipment take place. These basic operations are considered as the building blocks for all production processes. If the resource consumption of each building block can be quantified, not only at the operation itself but also at the on-site and off-site upstream and downstream processes to sustain the operation, the integral resource requirement of a whole specific production process can be quantified by the summation of the resource requirements of all building blocks involved. This methodology allows the development of a calculation tool for the quantification of the integral resource consumption with minimized data inventory. This tool will enable the selection of the most resource efficient production process and will indicate points of improvement. In this way production processes in pharmaceutical and fine chemical industries can become economically and ecologically more sustainable.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8015335

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5336–5343

Titre :	Experimental and theoretical studies on the start-up operation of a multivessel batch distillation column
Type de document :	texte imprimé
Auteurs :	Sven Gruetzmann, Auteur ; Georg Fieg, Auteur ; Sigurd Skogestad, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5336–5343
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Multivessel batch distillation Reflux strategy Start-up period
Résumé :	Multivessel batch distillation is a promising alternative to conventional batch distillation. Earlier studies proved the feasibility of temperature control in a closed operation mode, that is, when no product is removed until the end of the process. In this article, the influence of the reflux strategy during the initial start-up period is investigated in detail. This is a very important task in terms of the development of automation procedures in an industrial realization. The work is divided into three main parts. First, a rigorous dynamic model is introduced to describe the behavior of a multivessel batch distillation during start-up. Then, two experiments carried out on a laboratory scale column were chosen to validate the model. Finally, a sensitivity study is presented observing composition response while changing the reflux strategy. The results show that the process can be improved by applying a high reflux ratio and establishing the hydraulics as soon as possible.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800962b

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5336–5343

Titre :	Experimental and theoretical studies on the start-up operation of a multivessel batch distillation column
Type de document :	texte imprimé
Auteurs :	Sven Gruetzmann, Auteur ; Georg Fieg, Auteur ; Sigurd Skogestad, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5336–5343
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Multivessel batch distillation Reflux strategy Start-up period
Résumé :	Multivessel batch distillation is a promising alternative to conventional batch distillation. Earlier studies proved the feasibility of temperature control in a closed operation mode, that is, when no product is removed until the end of the process. In this article, the influence of the reflux strategy during the initial start-up period is investigated in detail. This is a very important task in terms of the development of automation procedures in an industrial realization. The work is divided into three main parts. First, a rigorous dynamic model is introduced to describe the behavior of a multivessel batch distillation during start-up. Then, two experiments carried out on a laboratory scale column were chosen to validate the model. Finally, a sensitivity study is presented observing composition response while changing the reflux strategy. The results show that the process can be improved by applying a high reflux ratio and establishing the hydraulics as soon as possible.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800962b

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5321–5335

Titre :	New mixed integer linear programming model for solving scheduling problems with special characteristics
Type de document :	texte imprimé
Auteurs :	Barbara Czuczai, Auteur ; Tivadar Farkas, Auteur ; Endre Rev, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5321–5335
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Mixed integer linear programming Scheduling problems
Résumé :	A new mixed integer linear programming (MILP) model suitable for optimizing scheduling problems typical in chemical and related industries is developed. These problems have characteristics like storage time constraints, operational connectivity restrictions, and continuous tasks with special precedence constraints. Therefore, a new MILP model is developed for handling these special scheduling problems. The numerical capability of the model is demonstrated using test problems of different complexity levels.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie800124g

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5317–5320

Titre :	Large-scale synthesis of MgCl2·6NH3 as an ammonia storage material
Type de document :	texte imprimé
Auteurs :	Hongliang Zhu, Auteur ; Kuihong Yao, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5317–5320
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Magnesium chloride hexammoniate Ammonia X-ray diffraction Fourier transform infrared spectroscopy Thermogravimetry
Résumé :	This Article reveals that magnesium chloride hexammoniate (MgCl2·6NH3) can be prepared by the reaction between magnesium silicide (Mg2Si) and ammonium chloride (NH4Cl) in liquid ammonia, which was developed by Komatsu Electronic Metals Corp. to produce silane (SiH4). The MgCl2·6NH3 product was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and thermogravimetry (TGA). XRD study showed that the solid product prepared by the experiment using a Mg2Si/NH4Cl mass ratio of 1:2.8 was phase-pure and highly crystalline MgCl2·6NH3. The FTIR spectrum exhibited the characteristic bands of coordinated ammonia molecules. In addition, the ammonia desorption behavior of the product were investigated by TGA, and its desorption reactions are given in this Article. In summary, this Article provides a new large-scale and low-cost synthesis method to produce MgCl2·6NH3, which has been emerging as an interesting functional material.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900177q

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5310–5316

Titre :	Nanostructured PLLA-hydroxyapatite scaffolds produced by a supercritical assisted technique
Type de document :	texte imprimé
Auteurs :	Ernesto Reverchon, Auteur ; Paola Pisanti, Auteur ; Stefano Cardea, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5310–5316
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Bone scaffolds Nanostructural properties Supercritical fluid assisted technique Hydroxyapatite nanoparticles
Résumé :	Temporary bone scaffolds can surrogate the extracellular matrix to favor the regeneration of tissues and organs. It is very difficult to obtain the coexistence of the macro-, micro-, and nanostructural properties necessary to mimic the organization of the human bone. To obtain all of these characteristics, we tested a supercritical fluid assisted technique for the formation of PLLA/ceramic scaffolds using hydroxyapatite (HA) nanoparticles loaded at up to 50% by weight of the polymer to improve the biomimethism and the mechanical properties of the scaffolds. We produced poly(l-lactic acid) scaffolds in relatively short time (<30 h), with a porosity higher than 90% and with a high interconnectivity. An internal structure formed by very long nanofibers of 200−400 nm diameter and prefixed macroscopic shape and size was also obtained. A maximum compressive modulus of 123 kPa was obtained, and the solvent residue was lower than 5 ppm.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8018752

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5302–5309

Titre :	Particle size and bulk powder flow control by supercritical antisolvent precipitation
Type de document :	texte imprimé
Auteurs :	Ranjit Thakur, Auteur ; Auburn E. Hudgins, Auteur ; Elisabete Goncalves, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5302–5309
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Poorly soluble drug Silicas Flowability Micrometer range Submicrometer range
Résumé :	The purpose of this study was to use silicas for controlling the particle size of a poorly soluble drug in the micrometer to submicrometer range and enhancing the flowability of those particles in a supercritical fluid process. The concept used consists in entrapping a fast precipitated drug into the silica pores and drying the resulting particles fast enough to avoid particle growth and ensure proper size control. Because silica will also enhance the bulk density, it will help in inducing higher flowability to the final product. To prove this concept, a suspension containing a poorly soluble drug and silica was processed using the batch gas antisolvent (GAS) method. Griseofulvin (GF) was used as a model of a poorly water-soluble drug substance, and two types of silica with different pore size and particle size, respectively, were tested. Each experiment was performed at various drug/silica ratios to determine the optimal ratio for particle size control. The products of each experiment were then analyzed using optical microscopy, X-ray powder diffraction (XRPD), and scanning electron microscopy (SEM). In addition, differential scanning calorimetric tests and dissolution rate studies were performed. Increasing the drug/silica ratio results in more pronounced particle size reduction and is accompanied by a change in drug particle morphology. The produced powders with silica showed enhanced flowability by visual inspection with the naked eye when compared to the neat drug. However, the available data shows that the silica has strong affinity with GF particles and affects the dissolution profile even though GF particle size is reduced. Kinetics instead of thermodynamics seems to be the controlling parameter for GF particles. All the experiments in this work were conducted in batch process mode, and further exploration is planned using the continuous supercritical antisolvent (SAS) process. Quantitative analysis of flowability is also part of the future work.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801324q

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5285–5301

Titre :	Prediction of solute partition coefficients between polyolefins and alcohols using a generalized flory-huggins approach
Type de document :	texte imprimé
Auteurs :	Guillaume Gillet, Auteur ; Vitrac, Olivier, Auteur ; Stéphane Desobry, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5285–5301
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	N-alkanes N-alcohols VolatilesFlory−Huggins approach
Résumé :	The partition coefficients of n-alkanes, n-alcohols, volatiles, and typical antioxidants between a low density polyethylene and several alcohols (methanol and ethanol) were predicted without fitting variables using an off-lattice Flory−Huggins approach. The main advantage of the proposed excluded volume constraint method was to sample at atomistic scale pairwise contact energies and the residual entropic contribution due to possible different conformers and reorientations. The positional entropy was considered both in the polymer and in the liquid as in the original Flory−Huggins theory. Possible biases due to the formulation and conformational sampling were analyzed for molecules different in size, in shape, and in stiffness. The predictions were close to the experimental uncertainty on the partition coefficients between the amorphous part of the polymer and the tested liquids. The present work confirmed that plastic additives, which are by design highly compatible with the polymer, had also a significant chemical affinity with polar liquids consisting of smaller molecules. Finally, a general predictive model of partition coefficients based on solubility coefficients was proposed.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801141h

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5276–5284

Titre :	A novel, potential microflora-activated carrier for a colon-specific drug delivery system and its characteristics
Type de document :	texte imprimé
Auteurs :	Ming-Jun Wang, Auteur ; Yu-Liang Xie, Auteur ; Qiao-Dong Zheng, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5276–5284
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Polyelectrolyte complex Sodium cellulose sulfate Colon-specific drug
Résumé :	A novel polyelectrolyte complex (PEC) formed by sodium cellulose sulfate (NaCS) and chitosan was prepared as a potential material for a colon-specific drug delivery system. The characteristics of NaCS−chitosan film were measured by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), in vitro degradation, and in vitro drug release experiments. SEM data indicated that the NaCS−chitosan film had relatively homogeneous and smooth morphology at the initial state and deformed after being immersed in simulated colonic fluid (SCF). FTIR data indicated that the NH3+ of the chitosan had reacted with the SO4− of the NaCS. In vitro degradation behavior revealed that NaCS−chitosan could be degraded by colon microflora and be hydrolyzed in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF). It is found in the experiment of in vitro drug release that the capsules formed by the NaCS−chitosan complex could release about 80% of the drug loaded in the SCF during 4 h. All these results indicated that the NaCS−chitosan complex shows excellent behavior for colon specificity and could be a potential material for a colon-specific drug delivery system.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801295y

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5266–5275

Titre :	Study on the synthesis of clay-based titanium silicalite-1 catalytic composite
Type de document :	texte imprimé
Auteurs :	Alex C. K. Yip, Auteur ; Frank L. Y. Lam, Auteur ; Xijun Hu, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5266–5275
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Clay-based titanium silicalite-1 (TS-1) catalytic composite Bentonite Crystallization
Résumé :	A clay-based titanium silicalite-1 (TS-1) catalytic composite was synthesized using hydrothermal treatment to crystallize TS-1 (300−400 nm) on a bentonite support. The presence of bentonite is favorable to supported growth attributed to the adsorption properties of the substrate which enhanced the interaction with the dissolved crystallizing species. The rapid crystallization on the bentonite support caused formation of silicalite-1 prior to Ti incorporation. An FT-IR spectroscopic study revealed that the Si defective sites were the exact location at which Ti was bonded. The Ti has been confirmed to exist in the form of a Si−O−Ti bridge instead of a Ti═O group in the clay-based TS-1. The influence of the synthesis temperature, duration, H2O to SiO2 molar ratio, and Ti and TPAOH concentrations in the starting gel on the characteristics of the clay-based TS-1 composite were also studied. In addition to the high and stable catalytic activity, the excellent settling efficiency of the clay-based TS-1 composite allowed it to become a reusable catalyst for TS-1-catalyzed processes.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9002798

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5255–5265

Titre :	Assessment of overall rate expressions and multiscale, microkinetic model uniqueness via experimental data injection : ammonia decomposition on Ru/γ-Al2O3 for hydrogen production
Type de document :	texte imprimé
Auteurs :	V. Prasad, Auteur ; A. M. Karim, Auteur ; A. Arya, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5255–5265
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Microkinetic models Framework Ru/γ-Al2O3 Hydrogen production Ammonia conversions
Résumé :	We introduce a framework for parameter estimation of microkinetic models via injecting data, collected in optimal regions of the “entire” experimental operating space, in models. We demonstrate this framework by combining differential conversion experimental data without transport limitations and models for ammonia decomposition on Ru/γ-Al2O3 for hydrogen production. Experiments indicate that there is significant H2 inhibition even at low ammonia conversions. Statistical model discrimination techniques indicate that multiple microkinetic parameter sets are able to describe quantitatively the experimental data, and some global rate expressions are also adequate. Among the best microkinetic models, nitrogen adsorption/desorption and the NHx dehydrogenation reactions are the kinetically significant reactions. It is found that macroscopic data (conversion) are insufficient for complete model discrimination; microscopic scale data are proposed for further model discrimination.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900144x

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5250–5254

Titre :	Nature of Ti species in the Li-Mg-N-H system for hydrogen storage : a theoretical and experimental investigation
Type de document :	texte imprimé
Auteurs :	Qiang Wang, Auteur ; Yungui Chen, Auteur ; Gao Niu, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5250–5254
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Li−Mg−N−H system Ti species Li2MgN2H2 Crystal structure
Résumé :	With the properties of the Li−Mg−N−H system improved by the doped Ti species, the activation energies of these systems were estimated by an Arrhenius plot, and this elucidated a slightly decreased value with doped TiF3. To explore the nature of Ti species in the Li−Mg−N−H system, the crystal structure of Li2MgN2H2 with doped Ti was calculated and determined as Li7TiMg4(N2H2)4 by a first principle approach. As a result, the Li−N and N−H bonds in Li7TiMg4(N2H2)4 were markedly weakened, which were evaluated by the energies of Li/H vacancy formation. Moreover, the weakened Li−N bonds indicated a considerable improvement in hydrogen absorption of Li2MgN2H2 with doped Ti, which was close to the experimental results. Otherwise, the weakened N−H bonds indicated a theoretical possibility that Li2MgN2H2 could be destabilized for further hydrogen desorption at an elevated temperature.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900070a

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5239–5249

Titre :	Ultradeep hydrodesulfurization and adsorptive desulfurization of diesel fuel on metal-rich nickel phosphides
Type de document :	texte imprimé
Auteurs :	Miron V. Landau, Auteur ; Moti Herskowitz, Auteur ; Tali Hoffman, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5239–5249
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Silica gel Diesel fuel Hydrodesulfurization Adsorptive desulfurization TPR methods
Résumé :	Three materials containing Ni2P, Ni12P5, and Ni3P phases on silica gel with surface area 320 m2/g at loadings of 32−37 wt % and the crystal size of NixP phases 30, 9, and 13 nm, respectively, were prepared by a combination of impregnation and TPR methods and tested in hydrodesulfurization (HDS) and adsorptive desulfurization (ADS) of diesel fuel. There were established opposite trends in changing the DS efficiency in two processes: The HDS rate constant decreased while the ADS sulfur capacity (breakthrough at 1 ppmw) increased with increasing the Ni to P ratio in NixP from 2 to 3. The observed behavior was attributed to the specific features of the densities of states (DOS) obtained from the density functional theory calculations of total and partial DOS for Ni and P in NixP phases and revealed in XPS measurements of binding energy of Ni 2p3/2- and P 2p-electrons. This attribution was consistent with the analysis of the relative part of d-electrons of Ni participating in bonding with p-electrons of phosphorus in these phases.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie9000579

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5230–5238

Titre :	Dehydration of C5−C12 linear 1-alcohols over η-alumina to fuel ethers
Type de document :	texte imprimé
Auteurs :	Reinier J. J. Nel, Auteur ; Arno de Klerk, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5230–5238
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Linear fuel ethers Olefin dimers Low temperature Fischer−Tropsch synthesis Alcohols
Résumé :	Naphtha from low temperature Fischer−Tropsch (LTFT) synthesis is rich in n-paraffins, but it also contains alcohols and olefins. These alcohols and olefins can be converted into linear fuel ethers and olefin dimers to improve the overall yield and quality of distillate from LTFT refining. The reaction network was studied for the conversion of 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-decanol, and 1-dodecanol over an η-alumina catalyst in a fixed bed flow reactor at 250−350 °C, 0−4 MPa, and WHSV of 1−4 h−1. The main products were the corresponding linear ethers and linear α-olefins. The highest ether yield (54%) was obtained at 300 °C, 1 MPa, and WHSV of 1 h−1 (unoptimized conditions). The main side-products were aldehydes and olefin dimers. Dehydration occurred predominantly on Lewis acid sites, with acid-catalyzed side-reactions taking place over Brønsted acid sites and dehydrogenation taking place over basic and/or redox sites. Dehydration to produce 2-olefins was cis-selective and occurred mainly over Lewis acid sites by dehydration−hydration−dehydration. GC-FID response factors for di-n-butyl ether and heavier linear ethers were determined experimentally. The GC-FID response factors were expressed in terms of the equivalent carbon number (ECN) concept as an ECN of −0.6 ± 0.1 for the linear ether oxygen atom, and this value could be mechanistically justified (literature ECN is −1.0).
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801930r

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5223–5229

Titre :	Selectivity and stability enhancement of iron oxide catalyst by ceria incorporation for selective oxidation of H2S to sulfur
Type de document :	texte imprimé
Auteurs :	D. D. Eslek Koyuncu, Auteur ; Sena Yasyerli, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5223–5229
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Iron oxide catalysts H2S Selective oxidation Ceria incorporation
Résumé :	Cerium incorporated iron oxide catalysts and a pure iron oxide catalytic material were prepared by the complexation technique and their catalytic performances were investigated for selective oxidation of H2S to elemental sulfur in a fixed-bed flow reactor. Ce−Fe mixed oxide catalyst having a Fe/Ce ratio of 1/1 (2Fe−2Ce) showed complete conversion and very high sulfur selectivity in the temperature range of 200−300 °C. Sulfur selectivity and stability of iron oxide catalyst was significantly enhanced by the incorporation of cerium into the catalyst structure. It was concluded that incorporation of ceria into the catalyst structure significantly improved the redox ability of the catalyst.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8017059

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5211–5222

Titre :	Candidate attainable regions for the oxidative dehydrogenation of n-butane using the recursive constant control (RCC) policy algorithm
Type de document :	texte imprimé
Auteurs :	David Milne, Auteur ; Tumisang Seodigeng, Auteur ; David Glasser, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5211–5222
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Attainable region Oxidative dehydrogenation N-butane
Résumé :	Attainable region (AR) ideas have previously been used to identify candidate attainable regions (ARCs) for the oxidative dehydrogenation (ODH) of n-butane to butenes and butadiene and in so doing to identify the maximum possible yields of different hydrocarbon product. Because of the large dimensionality of the problem, it was not possible then to do a complete AR analysis. Among the configurations considered, it was found that the reactor configuration for the respective ARCs in all instances was an inert membrane reactor (IMR) functioning as a differential side-stream reactor in which one of the reactants, oxygen, was introduced along the length of the reactor so as to maintain a very low and constant value of its partial pressure. Nevertheless, despite producing high yields of product, extremely large and impractical residence times ensued. In this paper, a new tool, the recursive convex control (RCC) policy, is used to identify the ARCs in the full dimensional space. These ARCs showed excellent agreement with those previously published, and the optimal reactor structures presented in those publications have been confirmed albeit with different oxygen control parameters. The maximum yields are now achieved with very much lower residence times. These results also confirm the benefit from using the AR approach on problems where a full AR analysis is not possible.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801600w

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5193–5210

Titre :	Particle formation in vinyl chloride emulsion polymerization : reaction modeling
Type de document :	texte imprimé
Auteurs :	Hugo M. Vale, Auteur ; Timothy F. L. McKenna, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5193–5210
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Particle size distribution Vinyl chloride monomer Polymerization
Résumé :	A mathematical model is developed to help quantify and improve our understanding of the formation of particles and the evolution of the particle size distribution (PSD) in the emulsion polymerization of vinyl chloride monomer (VCM). A special feature of the model is the computation of the coupled radical number and particle size distributions by means of the zero−one−two population balance equations. This approach is shown to be necessary when modeling processes that involve particle nucleation. Preliminary results are presented to illustrate the ability of the model in interpreting experimental data.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801406n

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5185–5192

Titre :	Loop reactor design and control for reversible exothermic reactions
Type de document :	texte imprimé
Auteurs :	Roman Sheinman, Auteur ; Moshe Sheintuch, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5185–5192
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Loop reactor Exothermic reaction Methanol VOC combustion
Résumé :	The loop reactor, in the form composed of several units, with feed and exit ports switching, is investigated for a reversible exothermic reaction like the synthesis of methanol. Unlike applications of VOC combustion, which have been extensively investigated and experimentally tested, the maximal temperature here is limited by equilibrium conditions and the advantage gained is due to the effectively periodic boundary conditions that describe the system: due to the rotating nature of the system, the stream undergoes cooling as it leaves the system, which in turn yields increasing conversions at an extent that depends on the parameters. We show that the system exhibits the slow-switching asymptote and the complex many-domains pattern that was identified for the irreversible case. The dynamic features within these domains are analyzed. Conversions are comparable to those in the commercially applied reactor with interstage cooling. Control procedures are suggested and tested.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801333w

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5177–5184

Titre :	Kinetic assessment of catalysts for the methanolysis of sodium borohydride for hydrogen generation
Type de document :	texte imprimé
Auteurs :	C.-t. F. Lo, Auteur ; K. Karan, Auteur ; B. R. Davis, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5177–5184
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Sodium borohydride Metal chlorides Platinum-coated lithium cobalt oxide Methanolysis
Résumé :	The efficacy of metal chlorides and platinum-coated lithium cobalt oxide as catalysts for the methanolysis of sodium borohydride over 45 to −20 °C was investigated. Among the metal chlorides tested, cobalt chloride exhibited maximum activity. In the presence of metal chlorides, the methanolysis reaction exhibited first-order kinetics with respect to the borohydride concentration. The rate constant for methanolysis reaction at −20 °C for 10 wt% cobalt chloride was determined to be 0.00136 s−1, which represents an over 100 times increase compared to the kinetics of the noncatalyzed methanolysis reaction. Platinum-coated lithium cobalt oxide also exhibits a significant rate increase compared to uncatalyzed methanolysis reaction at at 20 °C; however, no measurable activity was noticed at −20 °C. Further, the reaction kinetics appear to be zeroth-order with respect to borohydride concentration. In addition to the rate enhancement, all potential catalysts tested in this study showed a significant reduction in the lag time to less than 5 min at all temperatures. The activity of both cobalt chloride and platinum-coated lithium cobalt oxide were examined over several cycles and both catalysts had a reduced activity after the first cycle; however, the rate of hydrogen generation remained stable for the subsequent cycles.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie8009186

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5165–5176

Titre :	Model-based experimental analysis of a fixed-bed reactor for catalytic SO2 oxidation
Type de document :	texte imprimé
Auteurs :	J. C. Schöneberger, Auteur ; H. Arellano-Garcia, Auteur ; Günter Wozny, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5165–5176
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Nonlinear experimental design Kinetic models
Résumé :	In this work, a systematic approach based on nonlinear experimental design as an efficient tool for the validation of kinetic models is proposed which has the objective of computing experimental layouts, setups, and controls in order to optimize the statistical reliability of parameter estimates from the resulting experimental data. Furthermore, because the optimum experimental design is dependent on the values of the parameters, a sequential design is proposed. This represents an interaction between proposed experiments (e.g., inlet temperature and concentration), their evaluation, parameter estimation, and new design information such as reactor layout, sampling points, and temperature measurement positions. This follows an iterative procedure until all parameters achieve a prescribed statistical quality. Because of the fact that the overlaying optimization problem contains a highly nonlinear objective function, a hybrid optimization framework is also proposed to overcome the problem of local minima. To show the efficiency of the developed framework, it has been applied to the contact reaction. This reaction is a basic step in the sulfuric acid production and is carried out in a catalytic fixed-bed reactor called the contact horde.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801288d

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5160–5164

Titre :	Toward the Efficient production of methane/propane double hydrate
Type de document :	texte imprimé
Auteurs :	Melissa R. Prado, Auteur ; Yazmin Cazares, Auteur ; Kenneth C. Janda, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5160–5164
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Propane hydrate Methane gas Methane/propane gas mixture
Résumé :	Propane hydrate has been studied to investigate its use as a possible storage medium for methane gas. For practical purposes, hydrate formation needs to be efficient at near ambient conditions. Ice particles exposed to varying mixtures of propane and methane gas are found to form the double hydrate efficiently and may be quite effective for storing methane. For instance, exposure of the ice particles to a 2/1 methane/propane gas mixture for 18 h converts 66% of the ice to hydrate with 77% occupancy of the 512 cages and a final dissociation temperature of 287 K. The samples were then decomposed to determine the pressure versus temperature at a rate of 1 K/h. It was found that deviations from equilibrium were minor. The compositions of the hydrates were determined via gas chromatography. For the 180 μm particles employed in this study, 77% of the water was converted to double hydrate over 72 h. Additional experiments were performed in which the ice particles were sequentially exposed to propane and then methane to make the double hydrate. However, this technique did not prove to be as efficient as exposure to the mixed gas. Finally, gas composition measurements during decomposition of the double hydrates reveal that the two gases are released simultaneously.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie900027q

[article]
in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5125–5159

Titre :	State-of-the-art review of pinch analysis techniques for water network synthesis
Type de document :	texte imprimé
Auteurs :	Dominic Chwan Yee Foo, Auteur
Année de publication :	2009
Article en page(s) :	pp. 5125–5159
Note générale :	Chemical engineering
Langues :	Anglais (eng)
Mots-clés :	Water network synthesis Insight-based techniques Flow rate problems.
Résumé :	Water network synthesis has been an active area of research for the past one and a half decades. Many think that the technology reached a mature stage in the late 1990s, especially for the insight-based technique based on pinch analysis. The only review for the field dates back to 2000. However, many new papers published in this century reveal that new research gaps are found and more works were carried out to address the limitations of the “old” techniques. The main objective of this review is to provide a state-of-the-art overview of the insight-based techniques developed in the 21st century, particularly those developed for single impurity network of the fixed flow rate problems. Comparisons were also made between these recent techniques and those developed for the fixed load problems in the past century. Various flow rate targeting techniques developed for water reuse/recycle, regeneration, and wastewater treatment are reviewed in detail, along with the network design techniques that achieve the established targets. Finally, future research directions are outlined at the end of the review.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie801264c

Industrial & engineering chemistry research / Paul, Donald R. . Vol. 48 N° 11

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