Catalogue en ligne Bibliothèque Ecole Nationale Polytechnique d'Alger

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 9191-9197

Titre :	Crystallization and morphology in a 30/70 poly (ethylene succinate - co - 6 mol % butylene succinate) / poly (ethylene oxide) blend
Type de document :	texte imprimé
Auteurs :	Yan Yang, Auteur ; Zhaobin Qiu, Auteur
Année de publication :	2012
Article en page(s) :	pp. 9191-9197
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Morphology Crystallization
Résumé :	Crystallization and morphology were studied in a 30/70 poly(ethylene succinate-co-6 mol % butylene succinate)/ poly(ethylene oxide) (P(ES-co-6 mol % BS)/PEO) blend in this work. Depending on the crystallization conditions, including one-step and two-step crystallization, both components may crystallize separately or simultaneously. P(ES-co-6 mol % BS) and PEO crystallized separately via two-step crystallization. When the crystallization temperature was between the melting points of the two components, both the spherulitic growth rate and the overall crystallization rate of P(ES-co-6 mol % BS) decreased with increasing crystallization temperature; moreover, they were slower in the blend than in neat P(ES-co-6 mol % BS) at the same crystallization temperature. When the crystallization temperature was further lowered below the melting point of PEO, PEO crystallized only as tiny crystals within the P(ES-co-6 mol % BS) spherulites formed earlier, while its overall crystallization rate was increased significantly in the presence of the P(ES-co-6 mol % BS) crystals. In the case of simultaneous crystallization, growth of both P(ES-co-6 mol % BS) and PEO spherulites and the formation of interpenetrated spherulites were observed in a wide crystallization temperature range via one-step crystallization.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107477

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 9186-9190

Titre :	Effect of tray pressure drop on the trade - off between trays and energy
Type de document :	texte imprimé
Auteurs :	William L. Luyben, Auteur
Année de publication :	2012
Article en page(s) :	pp. 9186-9190
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Hydrodynamics Pressure drop
Résumé :	The classical trade-off between number of trays and energy consumption in distillation design is one of the fundamental concepts in chemical engineering. Conventional wisdom states that the use of more stages results in lower reflux ratios and lower reboiler duties for a specified separation. A hyperbolic relationship is expected in a plot of stages versus energy. More stages increase capital cost but reduce energy cost, so an economic optimum exists. Total annual cost, which balances capital and energy costs, is frequently used as the objective function to be minimized. This paper points out that the expected hyperbolic relationship does not apply in low-to-moderate pressure columns when the effect of tray pressure drop is included in the vapor―liquid and design equations. For a given reflux-drum pressure, adding more trays increases pressures in the lower part of the column. If the separation is favored by lower pressure, as is the case in many chemical systems, adding more trays can result in higher energy consumption because the higher pressures in the lower section of the column adversely affect relative volatilities. Two examples are presented that defy the conventional distillation wisdom of selecting a pressure that still permits the use of cooling water in the condenser in systems where decreasing temperatures increase relative volatility.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107476

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 9173-9185

Titre :	Application of space – time CE/SE method for solving gas – solid reaction and chemotaxis models
Type de document :	texte imprimé
Auteurs :	Shamsul Qamar, Auteur ; Waqas Ashraf, Auteur
Année de publication :	2012
Article en page(s) :	pp. 9173-9185
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Modeling Gas solid reaction
Résumé :	This work is concerned with the simulation of two different convection―diffusion―reaction type partial differential equations. The first one is the one-dimensional heterogeneous gas―solid reaction model encountered in a variety of chemical engineering problems. The exothermic nature of such reactions enlarges the gradients of temperature and concentrations that generate steep reaction fronts. The second one is the two-dimensional Keller―Segel model of the chemotaxis that generates delta-type singularities in the solution during a finite time. In its simplest form, the model is a nonlinear-coupled system of the convection-diffusion equation for the cell density and the reaction―diffusion equation for the chemoattractant concentration. The space-time conservation element and solution element (CE/SE) method is proposed for approximating both systems. The method has capabilities to capture sharp discontinuities of the solutions without spurious oscillations. To validate the accuracy and efficiency of the method, several case studies are carried out. The results of the current method are compared with the staggered central schemes.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107475

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 9164-9172

Titre :	Mass transfer studies in a rotating packed bed with novel rotors : Chemisorption of CO2
Type de document :	texte imprimé
Auteurs :	Yong Luo, Auteur ; Guang-Wen Chu, Auteur ; Hai-Kui Zou, Auteur
Année de publication :	2012
Article en page(s) :	pp. 9164-9172
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Carbon dioxide Chemisorption Rotor Packed bed Mass transfer
Résumé :	In this work, gas―liquid mass transfer characteristics, such as effective interfacial area (ae) and liquid side mass transfer coefficient (kL), were investigated in a rotating packed bed (RPB) contactor with 5 novel rotors equipped with blades in the packing section and 1 conventional rotor without blades and fully filled with the same packing. The chemisorption of CO2 into a NaOH solution was used to evaluate ae and kL within each rotor of the RPB. The experimental results indicate that the rotors with blades can significantly intensify the mass transfer process at all rotational speeds, over a range of gas―liquid ratios. The mass transfer rate achieved within these novel rotors was between 8% and 68% higher in comparison with the conventional rotor. A model based on the Danckwerts surface renewal theory was developed to calculate the liquid side volumetric mass transfer coefficient (kLae) in the rotor. The experimentally obtained values of kLae are in agreement with model predictions within ±15%.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107474

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 9153-9163

Titre :	Numerical simulation of a turbulent confined slot impinging jet
Type de document :	texte imprimé
Auteurs :	Shantanu Pramanik, Auteur ; A. Madhusudana Achari, Auteur ; Manab Kumar Das, Auteur
Année de publication :	2012
Article en page(s) :	pp. 9153-9163
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Numerical simulation
Résumé :	A detailed numerical study has been conducted for a two-dimensional, steady, incompressible, single confined turbulent slot jet impinging normally on a flat plate. The standard high Reynolds number two-equation k―ε eddy viscosity model has been used as the turbulence model. The separation between the jet-impingement surface and the confinement surface is varied from 2 to 20; however, detailed results are shown for 6.0. The turbulence intensity and the Reynolds number at the inlet are 2% and 11000 respectively. The mean flow and turbulent characteristics have been investigated. The distribution of streamwise mean velocity, static pressure, and turbulence have been presented for thorough understanding of the flow field. The integral of mean momentum, pressure, and turbulence fluctuation have been computed along the direction of flow. The locations of the reattachment point and center of the recirculating vortex have also been determined. A similarity profile was observed downstream of the reattachment point. A detailed discussion is provided on the pressure field, Reynolds stress, and kinetic energy and its dissipation rate.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107473

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 9145-9152

Titre :	Synthesis and characterization of carbonaceous materials from saccharides (Glucose and Lactose) and two waste biomasses by hydrothermal carbonization
Type de document :	texte imprimé
Auteurs :	Kivanc Aydincak, Auteur ; Tugrul Yumak, Auteur ; Ali Sinag, Auteur
Année de publication :	2012
Article en page(s) :	pp. 9145-9152
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Carbonization Biomass
Résumé :	Carbonaceous particles are synthesized under hydrothermal conditions using two waste biomasses (olive oil waste and hazel nutshell) and saccharides (glucose and lactose). A stainless steel autoclave with 75 mL of capacity was used to apply the hydrothermal carbonization (HTC) process to the starting materials stated above. In the experiments, 2.5 g of sample dispersed in 50 mL of deionized water is subjected to HTC at 180 °C for 4 h. H/C and O/C ratios for the chars were found to be more similar to the lignite than those of the starting materials. The heating values for the chars were found to be higher as compared to that of the feedstocks. FTIR investigations of the chars reveal that biochars of saccharides have different chemical structures compared with glucose and lactose, while biochars of waste biomasses are similar chemical nature with their starting materials. Hydroxymethylfurfural (HMF), phenol, acids, and aldehyde contents of aqueous phases were also determined. Solid-state 13C CP/MAS NMR analysis of the chars gave hints about the formation mechanism of sphere-structured biochars. Two different formation mechanisms for the biochars of waste biomasses and saccharides were proposed according to solid-state 13C CP/MAS NMR analysis results. The structure of biochar obtained from glucose and lactose involved furanic chains, while the biochars from olive oil waste and hazel nutshell have mainly aromatic structure.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107472

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 9136-9144

Titre :	The effect of surface properties in activated carbon on mercury adsorption
Type de document :	texte imprimé
Auteurs :	Liqing Li, Auteur ; Xin Li, Auteur ; Joo-Youp Lee, Auteur
Année de publication :	2012
Article en page(s) :	pp. 9136-9144
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Adsorption Activated carbon Surface properties
Résumé :	Physical and chemical properties of raw and modified activated carbon were analyzed to investigate the effects of adsorbate properties on activated carbon adsorption performance. Mercury adsorption was tested by cupric chloride impregnated activated carbon, which used water, acetone, and isopropyl alcohol as solutions. The results indicated that the adsorption capacity of Hg0 in the cupric chloride impregnated activated carbon in isopropyl alcohol was the greatest. Accumulation of Cu on the modified activated carbon surface and other oxygen functional groups was key in affecting the chemisorption of mercury. Two degadation steps were observed in TGA-MS measurements. Decomposition of functional groups containing two oxygen atoms in modified activated carbon took place in the first step, whereas most residual organic groups in activated carbon were primarily decomposed in a second step from 300 to 400 °C, the more organic groups present, the lower the temperature of thermal degradation.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107471

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 9129–9135

Titre :	Mass balance and performance analysis of potassium hydroxide activated carbon
Type de document :	texte imprimé
Auteurs :	R. Hilton, Auteur ; P. Bick, Auteur ; A. Tekeei, Auteur
Année de publication :	2012
Article en page(s) :	pp. 9129–9135
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Potassium hydroxide Carbon
Résumé :	Highly nanoporous carbon with surface areas in excess of 3,000 m2/g can be produced via potassium hydroxide (KOH) activation of a high surface area (1,150 m2/g) carbon intermediate. These materials have exhibited methane storage capabilities in excess of 20 wt % at ambient temperature with interest toward commercial production. In preparation for commercial production, detailed mass balances are needed to quantify yield and waste streams, understand the propensity to recycle the KOH, and to provide a benchmark for further optimization. Analytical processes used to evaluate produced carbon performance are detailed in addition to a mass balance on the reaction of KOH with carbon and a KOH balance. Carbon balances revealed that increasing activation time and activation temperature produce lower yields of carbon.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie301293t

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 9123-9128

Titre :	Boiling points of ternary azeotropic mixtures modeled with the use of the universal solvation equation and neural networks
Type de document :	texte imprimé
Auteurs :	Alexander A. Oliferenko, Auteur ; Polina V. Oliferenko, Auteur ; José S. Torrecilla, Auteur
Année de publication :	2012
Article en page(s) :	pp. 9123-9128
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Neural network Modeling Azeotropic mixture Boiling point
Résumé :	Azeotropic mixtures, an important class of technological fluids, constitute a challenge to theoretical modeling of their properties. The number of possible intermolecular interactions in multicomponent systems grows combinatorially as the number of components increases. Ab initio methods are barely applicable, because rather large clusters would need to be calculated, which is prohibitively time-consuming. The quantitative structure-property relationships (QSPR) method, which is efficient and extremely fast, could be a viable alternative approach, but the QSPR methodology requires adequate modification to provide a consistent treatment of multicomponent mixtures. We now report QSPR models for the prediction of normal boiling points of ternary azeotropic mixtures based on a training set of 78 published data points. A limited set of meticulously designed descriptors, together comprising the Universal Solvation Equation (J. Chem. Inf. Model. 2009, 49, 634), was used to provide input parameters for multiple regression and neural network models. The multiple regression model thus obtained is good for explanatory purposes, while the neural network model provides a better quality of fit, which is as high as 0.995 in terms of squared correlation coefficient. This model was also properly validated and analyzed in terms of parameter contributions and their nonlinearity characteristics.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107469

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 9117-9122

Titre :	Lactic acid extraction by means of long chain tertiary amines : A comparative theoretical and experimental study
Type de document :	texte imprimé
Auteurs :	G. Kyuchoukov, Auteur ; D. Yankov, Auteur
Année de publication :	2012
Article en page(s) :	pp. 9117-9122
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Lactic acid
Résumé :	The extraction of lactic acid with different long chain (from C8 to C12) tertiary amines was studied, both theoretically and experimentally. In view to determine the concentration of free acid and bounded with extractant acid in the aqueous phase, the experimental results were treated by mass balance equations. The minimal and maximal fractions of the free acid and bounded acid were calculated for different compositions of the organic phase. The obtained results clearly showed that in general the interaction product concentration in the aqueous phase could not be neglected and, in some cases, reached more than 50% from the total acid concentration. The disparate influences of inert and active diluents (dodecane and oleyl alcohol, respectively) were elucidated. It was shown that the overall distribution coefficient depends not only on the extraction product concentration in the aqueous phase but also on the composition of the organic phase.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie3005463

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 9101-9105

Titre :	Calcined Dolomite : Alternative to lime for minimizing undesirable element leachability from fly ash
Type de document :	texte imprimé
Auteurs :	Qinghai Guo, Auteur ; Eric J. Reardon, Auteur
Année de publication :	2012
Article en page(s) :	pp. 9101-9105
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Binders Carbon dioxide
Résumé :	Metal and ceramic forming applications using conventional binders are associated with a number of environmental problems such as toxic emissions and carcinogenic wastes released from conventional binder removal processes. Here, we examine several materials as possible binder candidates for a sustainable technology wherein the binder can be recovered and recycled by supercritical carbon dioxide. The candidates include an acetylated sugar, β-D-galactose pentaacetate, and two tert-butyl aromatics, 1,3,5-tri-tert-butylbenzene and 2,4,6tri-tert-butylphenol, which have significantly high solubility in supercritical carbon dioxide. We have demonstrated high-pressure carbon dioxide debinding of sand molds, each bound with candidate binders, at moderate temperatures and pressures. Practical operating conditions are suggested from the complementary binder-carbon dioxide phase behavior studies. Compared to solvent debinding, these novel binders exhibit rapid dissolution into supercritical CO2 due to enhanced transport properties. With high supercritical CO2 debinding efficiency, these materials are promising for developing more sustainable material forming processes, where toxic emissions and hazardous wastes of conventional debinding techniques can be eliminated, and materials recycling and reuse can be achieved.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107466

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 9101-9105

Titre :	Sustainable debinding and recovery of CO2 - soluble binders
Type de document :	texte imprimé
Auteurs :	Cerag Dilek, Auteur ; Lei Hong, Auteur ; Robert M. Enick, Auteur
Année de publication :	2012
Article en page(s) :	pp. 9101-9105
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Binders Carbon dioxide
Résumé :	Metal and ceramic forming applications using conventional binders are associated with a number of environmental problems such as toxic emissions and carcinogenic wastes released from conventional binder removal processes. Here, we examine several materials as possible binder candidates for a sustainable technology wherein the binder can be recovered and recycled by supercritical carbon dioxide. The candidates include an acetylated sugar, β-D-galactose pentaacetate, and two tert-butyl aromatics, 1,3,5-tri-tert-butylbenzene and 2,4,6tri-tert-butylphenol, which have significantly high solubility in supercritical carbon dioxide. We have demonstrated high-pressure carbon dioxide debinding of sand molds, each bound with candidate binders, at moderate temperatures and pressures. Practical operating conditions are suggested from the complementary binder-carbon dioxide phase behavior studies. Compared to solvent debinding, these novel binders exhibit rapid dissolution into supercritical CO2 due to enhanced transport properties. With high supercritical CO2 debinding efficiency, these materials are promising for developing more sustainable material forming processes, where toxic emissions and hazardous wastes of conventional debinding techniques can be eliminated, and materials recycling and reuse can be achieved.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107466

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 9094-9100

Titre :	Feedback - invariant approach to time - delay estimation for performance monitoring
Type de document :	texte imprimé
Auteurs :	Christopher A. Harrison, Auteur ; S. Joe Qin, Auteur
Année de publication :	2012
Article en page(s) :	pp. 9094-9100
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Surveillance Feedback
Résumé :	A simple time-delay estimation approach that requires temporarily retuning the existing PID controller is presented. Closed-loop output data are fitted with autoregressive moving average models at two different controller tunings. The time delay is determined by using the feedback-invariance principle that the closed-loop impulse response coefficients do not change inside the time-delay window. This approach requires no intervention to plant operation and does not estimate the open-loop process model but the time delay only. The estimated time delay is particularly suitable for use in control performance monitoring.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107465

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 9078–9093

Titre :	A novel two - level optimization framework based on constrained ordinal optimization and evolutionary algorithms for scheduling of multipipeline crude oil blending
Type de document :	texte imprimé
Auteurs :	Bai Liang, Auteur ; Jiang Yongheng, Auteur ; Huang Dexian, Auteur
Année de publication :	2012
Article en page(s) :	pp. 9078–9093
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Optimization Oil
Résumé :	This paper introduces a practical scheduling of multipipeline crude oil blending (SMCOB) problem. It is formulated as a complex mixed integer nonlinear programming (MINLP) model, taking the charging sequence and flow rates of oil tanks as decision variables, which cannot be efficiently solved by traditional deterministic methods and solvers. Then, a novel two-level optimization framework based on constrained ordinal optimization (COO) and evolutionary algorithms (EA) is proposed. The solution methodology has two stages based on the main procedures of COO. At the crude evaluation stage, discrete EA are used to search for sequence solutions in the outer level. It evolves the sequence solutions on the basis of their rough evaluation of the feasibility and objective value obtained from the inner level and keeps certain number of probably best sequence solutions. At the accurate evaluation stage, the probably best sequence solutions kept by the crude evaluation stage are accurately evaluated by inner-level continuous EA. The COO approach ensures that some true good enough sequence and flow rate solutions can be obtained from the accurate evaluation stage with high probability. COO-based EA are compared with mixed-coding EA to verify the framework’s efficiency and robustness.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie202224w

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 9061-9077

Titre :	Efficient combustion : A process synthesis approach to improve the efficiency of coal - fired power stations
Type de document :	texte imprimé
Auteurs :	Baraka Celestin Sempuga, Auteur ; Bilal Patel, Auteur ; Diane Hildebrandt, Auteur
Année de publication :	2012
Article en page(s) :	pp. 9061-9077
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Coal Combustion
Résumé :	Much of our energy reserves are locked in the chemical potential of chemicals such as fossil fuels. The majority of CO2 emissions caused by human activities come from the combustion of these fuels. Typically, the fuel is burned with oxygen (air), and heat is released. This heat is then used to drive power cycles to produce, for example, electricity in a power plant or motion in the motor car engine. Often, the performance of these processes is assessed in term of thermal efficiency (ηth), which considers how much of the energy released in the combustion process is turned into work. This is not a good representation of how efficient the process is, however, as an idealized Carnot engine, which takes heat from a heat source at a temperature TH and rejects heat to a heat sink at the reference temperature To = 298.15 K, is reversible and thus takes all of the work potential (exergy) of heat and converts this to work. Thus, the Carnot engine might have only 40% efficiency in terms of converting heat to work (ηth), but because it is fully reversible, it generates no entropy, and therefore, it is 100% efficient in terms of recovering the work potential of heat. However, there is a much more fundamental efficiency that should be considered, namely, how much of the chemical potential of the fuel is turned into work. When combustion processes are considered in this way, it becomes clear that some of the major inefficiencies are in the chemical transformations that produce heat, rather than in the power cycles that convert heat to work. A very important question remains: Is it possible to do these transformations more efficiently and thereby conserve the work potential or chemical potential in fuel? This article shows, from a fundamental thermodynamic analysis, that it is not possible to combust carbon-based materials efficiently, that is, that the process of combustion of carbon-based materials is irreversible and that a considerable amount of the chemical potential of the fuel is lost during the combustion process. However, other substances or chemistries are explored in this work, and it is shown that some of these have the potential for more reversible combustion. These options are explored, and their potential implementation is examined by considering a coal-based power plant as an example. In particular, it is shown that CO2 emissions could be significantly reduced by using different chemical pathways to do the combustion and by combining power and chemical production.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107463

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 9041-9060

Titre :	A hybrid neural network model predictive control with zone penalty weights for type 1 diabetes mellitus
Type de document :	texte imprimé
Auteurs :	Shih-Wei Liu, Auteur ; Huang, Hsiao-Ping, Auteur ; Chia-Hung Lin, Auteur
Année de publication :	2012
Article en page(s) :	pp. 9041-9060
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Predictive control Modeling Neural network
Résumé :	In this paper, a hybrid neural network model is developed to predict and control the blood glucose (BG) of the patient who has type 1 diabetes mellitus (T1DM). The proposed model consists of two parts: a linear finite impulse response (FIR) model and a nonlinear autoregessive exogenous input (NARX) network. A recently developed and well-acknowledged meal simulation model of the glucose-insulin system for T1DM is employed to create virtual subjects. Data from virtual subjects are used to identify an intermediate physiological model, and then our proposed hybrid model is trained and validated based on this intermediate model. The key features of the resulting hybrid model are that it reveals satisfactory accuracy of long-term prediction and does not require an immeasurable state for model initialization. The developed hybrid model is then embedded in a nonlinear model predictive control (MPC) controller with zone penalty weights, and this closed-loop controller is implemented on these virtual subjects for simulation-based preclinical testing. The results show that promising glycemic control performance can be achieved. Moreover, this overall BG control methodology is easily portable and has the ability to arbitrarily start the therapeutic control at any initial point.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107462

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 9032-9040

Titre :	Catalytic effect of magnesium ions on silicic acid polycondensation and inhibition strategies based on chelation
Type de document :	texte imprimé
Auteurs :	Konstantinos D. Demadis, Auteur ; Antonia Ketsetzi, Auteur ; Eva-Maria Sarigiannidou, Auteur
Année de publication :	2012
Article en page(s) :	pp. 9032-9040
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Condensation polymerization Catalytic reaction
Résumé :	The catalytic role of Mg2+ ions in the polycondensation of silicic acid to form amorphous silica has been investigated in detail. This behavior is pH-dependent. As pH increases (herein, the three pH values 8.0, 9.0, and 9.5 were tested), the catalytic effect of Mg2+ ions becomes more pronounced. Also, this behavior is directly proportional to the concentration of Mg2+. Ethylenediaminetetraacetic acid (EDTA) can inhibit this catalytic effect by strongly chelating the Mg2+ ions. This research can be further expanded to other chelating agents that have an affinity for Mg2+ ions.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107461

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 9023-9031

Titre :	Characterization of hydrochars produced by hydrothermal carbonization of lignin, cellulose, d - xylose, and wood meal
Type de document :	texte imprimé
Auteurs :	Shimin Kang, Auteur ; Xianglan Li, Auteur ; Juan Fan, Auteur
Année de publication :	2012
Article en page(s) :	pp. 9023-9031
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Wood Carbonization
Résumé :	Hydrothermal carbonization of cellulose, lignin, D-xylose (substitute for hemicellulose), and wood meal (WM) was experimentally conducted between 225 and 265 °C, and the chemical and structural properties of the hydrochars were investigated. The hydrochar yield is between 45 and 60%, and the yield trend of the feedstock is lignin > WM > cellulose > D-xylose. The hydrochars seem stable below 300 °C, and aromatic structure is formed in all of these hydrochars. The C content, C recovery, energy recovery, ratio of C/O, and ratio of C/H in all of these hydrochars are among 63―75%, 80―87%, 78―89%, 2.3― 4.1, and 12―15, respectively. The higher heating value (HHV) of the hydrochars is among 24-30 MJ/kg, with an increase of 45―91% compared with the corresponding feedstock. The carbonization mechanism is proposed, and furfural is found to be an important intermediate product during D-xylose hydrochar production, while lignin hydrothermal carbonization products are made of polyaromatic hydrochar and phenolic hydrochar. The formation of microspheres on the surface of cellulose and WM hydrochars is discussed, and transformation of the hemicellulose should be the reaction for WM microsphere production.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107460

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 9016-9022

Titre :	Controllable preparation of polyacrylamide hydrogel microspheres in a coaxial microfluidic device
Type de document :	texte imprimé
Auteurs :	Bodong Yang, Auteur ; Yangcheng Lu, Auteur ; Guangsheng Luo, Auteur
Année de publication :	2012
Article en page(s) :	pp. 9016-9022
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Fluid mechanics Microfluidics Microsphere Preparation
Résumé :	A thermal-initiated polymerization procedure is described for the controlled preparation of monodispersed polyacrylamide (PAM) hydrogel microspheres. A coaxial microfluidic device was designed to disperse uniform drops (∼500 μm) of acrylamide monomer aqueous solution into n-octane. Using a delay loop immersed into a heat bath, the polymerization is initiated and carried out in separate droplets. Combining the improvement of heat transfer in the microfluidic device and the sufficient addition of n-octane, the controllable preparation can still be achieved at 95 °C, much higher than 20-60 °C as reported prevalently. Herein, the PAM microspheres can be prepared within 2 min or less, with the CV of diameter less than 4%. Furthermore, based on this controllable reaction platform, PAM microspheres were prepared at various reaction temperatures (higher than 90 °C) and monomer solution compositions to investigate the fundamental rules of controlling on their skeleton structure and absorbent capacity in deionized water.
DEWEY :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107459

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 9007-9015

Titre :	Novel modification of a macroporous stainless steel tube by electroless Ni plating for use as a substrate for preparation of nanoporous carbon membranes
Type de document :	texte imprimé
Auteurs :	B. S. Liu, Auteur ; Y. H. Guo, Auteur ; F. Yuan, Auteur
Année de publication :	2012
Article en page(s) :	pp. 9007-9015
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Inorganic membrane Preparation Stainless steel Macroporosity
Résumé :	Nanoporous carbon (NPC)/Ni-P composite membranes were prepared on electroless Ni-plating-modified porous stainless steel tubes (PSSTs) by carbonizing polyimide or cellulose acetate precursors at 700 °C, in a nitrogen atmosphere. The performance of the membranes was evaluated by single-gas permeation and binary-gas mixture separation. The effects of the substrate with or without modification on gas permeation were studied, and the diffusion mechanism of the gases through the membranes was analyzed. The real separation factors of gas mixtures through the NPC/Ni-P composite membranes were much higher than those through the nanoporous carbon membranes (NPCMs) prepared on the unmodified substrate, especially those for H2/CH4 and H2/CO2. The weight loss rate of polymer precursors was investigated by TG/DTG. The specific surface areas of the membranes and the crystallization of the Ni-P alloy layer were characterized by means of the BET and DSC techniques, respectively, indicating that localized electroless Ni plating can reduce the pore diameter of PSST effectively and regulate the pore size distribution.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107458

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8999-9006

Titre :	A pH - sensitive laser - induced fluorescence technique to monitor mass transfer in multiphase flows in microfluidic devices
Type de document :	texte imprimé
Auteurs :	Simon Kuhn, Auteur ; Klavs F. Jensen, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8999-9006
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Fluid mechanics Microfluidics Multiphase flow Mass transfer Surveillance Laser induced fluorescence pH
Résumé :	We present a pH-sensitive laser-induced fluorescence (LIF) technique to investigate mass transfer in reactive flows. As a fluorescent dye, we used 5-(and-6)-carboxy SNARF-1, which, when excited with a pulsed Nd:YAG laser at 532 nm, provides good sensitivity in the range 4 ≤ pH ≤ 12. For validation, we first applied the dye to single-phase reactive flows by investigating the neutralization of sodium hydroxide with hydrochloric acid. Comparison to the classical passive mixing case showed that this dye was able to capture the reaction progress and to quantify the mass transport. Next, we investigated the absorption of CO2 in an alkaline solution using gas―liquid flow and found that the LIF technique is able to quantify the local mass-transfer rate in microfluidic systems. Results for different microchannel geometries highlight the strong connection between local mass transfer and secondary flow structures in gas―liquid Taylor flow.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107457

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8992-8998

Titre :	Optimization of extraction process and kinetics of sterculia foetida seed oil and its process augmentation for biodiesel production
Type de document :	texte imprimé
Auteurs :	Pandian Sivakumar, Auteur ; Karuppiah Subramanian Parthiban, Auteur ; Padmanaban Sivakumar, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8992-8998
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Production Kinetics Extraction process Optimization
Résumé :	This article reports optimization and kinetic studies on extraction of Sterculia foetida seed oil and process optimization for biodiesel production from the same. The oil extraction follows first-order kinetics, and the yield was found to reach a maximum of 55.58 wt % for a 1:12 seed-to-hexane weight ratio. The activation energy and activation thermodynamic parameters at 338 K were determined as Ea = 69.441 kJ mol―1, ΔH‡ = 66.63 kJ mol―1, ΔS‡ = ―238.07 J mol―1 K―1, and ΔG‡ = 147.09 kJ mol―1. Complete physicochemical properties of the oil were analyzed using standard methods. The low acid value of 0.42 mg of KOH g―1 for fresh oil enables alkali catalytic transesterification. Different biodiesel production parameters including methanol-to-oil molar ratio, catalyst concentration, and reaction temperature were examined. An optimum yield of 95.4 wt % with a conversion of 98.91% was achieved at values of 6:1, 0.9 wt %, and 338 K, respectively. The fuel properties of the produced biodiesel were compared with the ASTM D6751 biodiesel standard.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107456

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8985-8991

Titre :	Nonisothermal kinetic study : IV. Comparative methods to evaluate Ea for thermal decomposition of KZn2 (PO4) (HPO4) synthesized by a simple route
Type de document :	texte imprimé
Auteurs :	Zhipeng Chen, Auteur ; Qian Chai, Auteur ; Sen Liao, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8985-8991
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Thermal decomposition Kinetics
Résumé :	The single-phase KZn2(PO4)(HPO4) was synthesized via solid-state reaction at 80 °C using K3PO4·3H2O, K2HPO4·3H2O, and ZnSO4·7H2O as raw materials. The thermal decomposition of KZn2(PO4)(HPO4) experienced one step, which was the intramolecular dehydration of the protonated phosphate groups to form Zn2P2O7. The apparent activation energy Ea was estimated with six comparative isoconversional procedures. The average value of the apparent activation energy Ea associated with the thermal decomposition of KZn2(PO4)(HPO4) was determined to be 411.49 ± 14.37 kJ mol―1, which demonstrates that the thermal decomposition of KZn2(PO4)(HPO4) is a single-step kinetic process and can be described by a unique kinetic triplet [Ea, A, g(a)]. A new modified method for multiple rate isotemperature was used to define the most probable reaction mechanism g(a), and reliability of the used method for the determination of the kinetic mechanism was tested by the comparison between experimental plots and modeled results for every heating rate. The results show that the mechanism function is reliable. The value of pre-exponential factor A was obtained on the basis of Ea and g(a). Some thermodynamic functions (ΔS‡, ΔH‡, and AG*) of the transition state complex were also calculated.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107455

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8979-8984

Titre :	Alumina supported fenton - like systems for the catalytic wet peroxide oxidation of phenol solutions
Type de document :	texte imprimé
Auteurs :	Carla di Luca, Auteur ; Fernando Ivorra, Auteur ; Paola Massa, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8979-8984
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Oxidation Catalytic reaction Fenton reaction
Résumé :	Fe2O3/Al2O3 catalysts (2% Fe) were prepared and characterized by XRD, BET, Raman, and SEM-EDAX. The systems were tested for the catalytic oxidation of phenol solutions (5000 ppm) with H2O2. The effects of reaction temperature, catalyst loading, phenol initial concentration, and H2O2:phenol molar ratio were evaluated. The relatively low oxidant consumption rates favored increased mineralization levels at substoichiometric H2O2 initial concentrations. The stability of the catalytic system was improved by means of a thermal treatment at 900 °C, which did not seriously affect the overall reaction performance.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107454

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8974-8978

Titre :	Investigation of Cu - based catalyst for direct synthesis of ethyl acetate from ethanol : Improvement of thermal stability of Cu – Cr – Zr composite oxide catalyst by addition of Mn Promoter
Type de document :	texte imprimé
Auteurs :	Li Xiaofei, Auteur ; Jiang Haoxi, Auteur ; Li Guiming, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8974-8978
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Promoter Composite material Thermal stability Catalyst
Résumé :	A Mn promoter was introduced into a Cu-Cr-Zr composite oxide catalyst for the direct synthesis of ethyl acetate from ethanol dehydrogenation by means of coprecipitation method. The effects of the Mn promoter on the structure and catalytic performance of the catalyst were investigated with characterization techniques including XRD, TPR, XPS, and N2O TPD. An interaction between the Mn promoter and the CuO in the catalyst was found to exist, and it improved the dispersion of the Cu component on the catalyst surface and decreased the size of CuO crystal particles, thereby increasing the thermal stability of the catalyst. The results of long-duration activity tests indicated that the Mn-promoted CCZ (Cu―Cr―Zr) catalyst maintained its activity and showed good stability.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107453

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8966-8973

Titre :	Fabrication of (Calcein – ZnS)n ordered ultrathin films on the basis of layered double hydroxide and its ethanol sensing behavior
Type de document :	texte imprimé
Auteurs :	Ying Guo, Auteur ; Yaping Xiao, Auteur ; Limin Zhang, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8966-8973
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Ultrathin films N order
Résumé :	(Calcein―ZnS)n ultrathin films (UTFs) were fabricated through a two-step procedure including the layer-by-layer (LBL) assembly of calcein and exfoliated Zn2Al layered double hydroxide (LDH) nanosheets, followed by an in situ gas/solid reaction with H2S. The assembly process of calcein and exfoliated LDH was monitored by UV―vis absorption measurements to get a stepwise and regular growth of the (calcein―LDH)n UTFs upon increasing the deposited cycles. By an in situ gas―solid reaction with H2S, the resulting sulfurization derivatives denoted as (calcein―ZnS), UTFs were obtained. The resulting (calcein―ZnS)30 UTF possesses high ethanol sensing performance (response value is 8.9-100 ppm ethanol) at relatively low working temperature (90 °C). The LBL assembly process and chemical conversion technique based on Zn2Al―LDH combine the functional organic molecules and inorganic semiconductor, which enables us to develop innovative composite materials with adjustable compositions for a broad range of applications.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107452

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8957–8965

Titre :	Design, synthesis, and characterization of bismaleimide Co - curing elastomers
Type de document :	texte imprimé
Auteurs :	Karthik Vikram Siva Shanmugam, Auteur ; J. Scott Parent, Auteur ; Ralph A. Whitney, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8957–8965
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Elastomers Copolymerization
Résumé :	Isobutylene-rich elastomers bearing functional groups that engage N-arylmaleimides in C–H bond addition and/or alternating copolymerization are described. While inactive to cross-linking when treated at high temperature with peroxide alone, these co-curing elastomers can be cross-linked substantially when combined with bismaleimide coagents such as N,N′-m-phenylenedimaleimide (BMI). Poly(isobutylene-co-isoprene) (IIR) samples containing relatively high amounts of residual isoprene unsaturation are shown to provide relatively low coagent cure reactivity, whereas IIR derivatives bearing pendant polyether or vinyl ether functionality are shown to provide exceptional cross-linking rates and extents when treated with identical BMI formulations. The design of such co-curing elastomers is discussed, along with the physical properties of the resulting vulcanizates.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie300795b

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8945-8956

Titre :	Modeling of chemical equilibrium and gas phase behavior for the direct synthesis of dimethyl carbonate from CO2 and methanol
Type de document :	texte imprimé
Auteurs :	Felipe Bustamante, Auteur ; Andrés F. Orrego, Auteur ; Sebastian Villegas, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8945-8956
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Carbon dioxide Chemical equilibrium Modeling
Résumé :	The chemical and gas phase equilibrium of the direct synthesis of dimethyl carbonate (DMC) from methanol (MeOH) and CO2 was modeled under mild conditions of temperature and pressure. Deviations from ideality for the quaternary mixture (CO2 + MeOH + DMC + H2O) were estimated using the γ ― φ thermodynamic approach. Binary interaction parameters (kij) and UNIQUAC parameters (Aij) were extracted from VLE data reported in the literature. The results show that MeOH conversion is enhanced by increasing the pressure and reducing the temperature; however, pressure and temperature are bounded by the dew point. Data of P, T, and vapor compositions obtained from modeling chemical equilibrium were used to predict dew points of the reacting mixture and to establish the region of T and P where the gas-phase reaction could be carried out. To avoid condensation, an increase in pressure must be accompanied by a temperature increase. Moreover, the larger the methanol concentration in the feed mixture is, the higher is the required temperature.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107450

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8939-8944

Titre :	Effects of methanol and carbon tetrachloride on sonolysis of 1,4 - dioxane in relation to temperature
Type de document :	texte imprimé
Auteurs :	Hyun-Seok Son, Auteur ; Kyung-Duk Zoh, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8939-8944
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Sonolysis
Résumé :	The effects of methanol and carbon tetrachloride (CT) on the degradation of 1,4-dioxane via ultrasound irradiation were investigated by estimating the production rate of H2O2 and the degradation efficiency of the substrates. At 5 and 20 °C, the production rate of H2O2 significantly decreased as methanol concentration in pure water increased and during sonolysis of 1,4-dixoane. The sonolytic efficiency of 1,4-dioxane with methanol greatly decreased over 60 min at 5 °C and 90 min at 20 °C. Production of H2O2 increased during CT sonolysis at 5 °C but decreased at 20 and 40 °C, with efficiency greatest at 5 °C. Sonolysis of 1,4-dioxane with CT was enhanced from the beginning reaction at 5 °C and 40 min at 20 °C compared to the reactions without CT but was slightly lower at 40 °C. The results elucidate sonolytic mechanisms, such as pyrolysis and redox, in relation to reaction temperature, as well as suggest sonolytic conditions for the effective degradation of CT and 1,4-dioxane.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107449

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8928–8938

Titre :	Green fuel production using the permSMBR technology
Type de document :	texte imprimé
Auteurs :	Carla S. M. Pereira, Auteur ; Viviana M. T. M. Silva, Auteur ; Alirio E. Rodrigues, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8928–8938
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Green fuel
Résumé :	The production of the green fuel acetaldehyde dibutylacetal (1,1-dibutoxyethane, DBE) was implemented by means of a new hybrid technology, the Simulated Moving Bed Membrane Reactor (PermSMBR), which consists in a Simulated Moving Bed Reactor (SMBR) integrated with membranes. The PermSMBR and SMBR processes performances were numerically evaluated and compared. The new hybrid technology proved to be a very efficient process for DBE production, leading to a productivity of 70.77 kgDBE·Lresin-1·day-1 with a desorbent consumption of 0.33 Ln-Butanol/kgDBE, which corresponds to a productivity enhancement of 31% and a desorbent consumption reduction of 88% when compared with the SMBR technology.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie201951d

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8922–8927

Titre :	Influence of hydrogen in catalytic deoxygenation of fatty acids and their derivatives over Pd/C
Type de document :	texte imprimé
Auteurs :	Bartosz Rozmyslowicz, Auteur ; Paivi Maki-Arvela, Auteur ; Anton Tokarev, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8922–8927
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Hydrogen Catalytic Deoxygenation
Résumé :	The influence of hydrogen on the catalytic deoxygenation of fatty acids was investigated in the semibatch reactor over a mesoporous 5 wt % Pd/C (Sibunit) catalyst. Transformations of a model fatty acid (lauric acid) and reaction intermediates (lauric aldehyde and lauryl alcohol) were performed under inert and hydrogen rich atmosphere. Analysis of the liquid and gas phases of the reaction mixture revealed that different reactions occurred depending on hydrogen content in the reaction atmosphere. A higher yield of hydrocarbons (59 mol %) was obtained in the fatty acid deoxygenation under hydrogen pressure compared to an experiment under argon where the yield of hydrocarbons reached 39 mol % after 300 min of the reaction. Different product distributions, intermediates and reaction pathways depending on hydrogen content in the reaction atmosphere, are discussed.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie202421x

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8913-8921

Titre :	Modeling and simulation of hydrocracking of fischer – tropsch hydrocarbons in a catalytic microchannel reactor
Type de document :	texte imprimé
Auteurs :	M. Irfan Hosukoglu, Auteur ; Mustafa Karakaya, Auteur ; Ahmet K. Avci, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8913-8921
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Microreactor Catalytic reaction Hydrocracking Modeling
Résumé :	Product quality of Fischer-Tropsch synthesis is improved by catalytic hydrocracking which converts heavy hydrocarbon fractions (wax) to commercially valuable fuels. The process is highly exothermic and requires strict temperature control; high temperatures cause overcracking to lower, commercially undesired hydrocarbons, whereas low temperatures reduce the conversions. Running hydrocracking in microchannel reactors is promising, since submillimeter dimensions lead to significant compaction that favors robust temperature control. This work investigates modeling and simulation of hydrocracking in a heat-exchange-integrated microchannel reactor involving parallel groups of square-shaped cooling and catalyst-coated reaction channels. Effects of material type and thickness of the wall separating the channels, and operating parameters (reactant and coolant feed temperatures and space velocity of the reactant stream) on reaction temperature and product distribution are investigated. Mole fractions of the products in the diesel cut (C19―C22) and jet cut (C11―C18) ranges are highly sensitive to operating parameters due to fast heat transport. The process suffers from overcooling and reduced conversions in reactors characterized by thicker walls with high thermal conductivities, whereas hot spots may exist in reactors characterized by thinner walls with low thermal conductivities. Temperature and product distributions in hydrocracking can be optimized within the pertinent operating window by careful configuration of the reactor.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107446

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8903–8912

Titre :	Kinetics and mechanism of H2O2 direct synthesis over a Pd/C catalyst in a batch reactor
Type de document :	texte imprimé
Auteurs :	Pierdomenico Biasi, Auteur ; Nicola Gemo, Auteur ; José Rafael Hernández Carucci, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8903–8912
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Kinetics Catalyst
Résumé :	Kinetic experiments of the decomposition, hydrogenation, and direct synthesis of hydrogen peroxide were performed on a commercial Pd/C catalyst. Temperature effects and subsequent hydrogen addition were investigated without using promoters. The hydrogen amount in the liquid phase was measured online by using a Fugatron Instrument to investigate the effect of the gas on the direct synthesis. Decomposition and hydrogenation reactions were affected differently by the temperatures used during the experiments. The formation of hydrogen peroxide showed different behaviors with different hydrogen feeding policies. The hydrogen dissolved in the liquid phase measured experimentally was correlated with the hydrogen peroxide production. As the amount of dissolved hydrogen increases in the liquid phase the direct synthesis rate increases, while the reaction slows down as the hydrogen pressure is decreased. The selectivity is also affected by the H2 recharges. Every time that hydrogen is recharged in the reactor (during the direct synthesis) the selectivity toward H2O2 increases. Two different methods to recharge H2 during the reaction were analyzed. The first method consists in feeding the hydrogen when it is totally consumed, the second one in refilling hydrogen in the reactor before its total consumption. The hydrogen solubility was found as an important parameter for the direct synthesis. An explanation on hydrogen peroxide formation was given taking into account the H2/Pd ratio.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie2021398

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8891-8902

Titre :	Euler – lagrange CFD simulation of a gas – liquid fluidized bed reactor for the mineralization of high - strength phenolic wastewaters
Type de document :	texte imprimé
Auteurs :	Rodrigo J. G. Lopes, Auteur ; M.L.N. Perdigoto, Auteur ; Rosa M. Quinta-Ferreira, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8891-8902
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Waste water Strength Mineralization Fluidized bed reactor Computational fluid dynamics
Résumé :	A state-of-the-art Euler―Lagrange model was developed to simulate the ozonation of phenol-like pollutants in a bubble column reactor. First, several numerical simulations were performed to evaluate on how the bubble velocity and oxidant concentration can improve the detoxification of liquid effluents by noncatalytic ozonation. Second, the effect of inlet ozone velocity as well as the influence of inlet ozone concentration has been investigated comparatively under different process conditions. We found that the Eulerian―Lagrangian computations have correctly handled the experimental observations in the quasi-homogeneous flow regime both in terms of the gas―liquid velocity distributions and normalized pollutant concentration. The numerical confidence exhibited by the CFD simulations underlined the ozonation-based technology as one promising application to improve the environmental performance of bubble columns, which is typically operated under the low-interaction regimes, especially when the mass transfer of ozone is rate controlling and affects the mineralization rate. The interstitial flow maps have been successfully correlated with total organic carbon concentration profles as function of inlet ozone velocities and concentrations. Moreover, the multiphase CFD framework gathered positively the mixing degree induced by different inlet bubble velocities as demonstrated by the total organic carbon concentration mappings and experimental conversion data.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107444

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8883-8890

Titre :	Direct synthesis of hydrogen peroxide in a trickle bed reactor : Comparison of Pd - based catalysts
Type de document :	texte imprimé
Auteurs :	Pierdomenico Biasi, Auteur ; Paolo Canu, Auteur ; Federica Menegazzo, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8883-8890
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Catalyst Trickle bed reactor Hydrogen peroxide
Résumé :	Palladium catalysts based on different supports, silica (SiO2), zirconia (Z), sulfated ceria (CeS), and sulfated zirconia (ZS), previously tested in a semibatch reactor, were chosen to demonstrate how the direct synthesis process can be improved by continuous operation in a three-phase fixed bed. The gas and liquid flow rates were systematically varied to find suitable combinations for a maximum hydrogen peroxide production rate and selectivity. Different catalysts gave the same results in terms of selectivity and production rate with different operating conditions. A selectivity of 60% and 70% was found with two different catalysts (namely, Pd-ZS and Pd-CeS). Very interestingly those selectivities were found with different gas and liquid flow rates (i.e., 70% of selectivity for Pd-ZS with liquid 1 mL/min and gas 2.7 mL/min, liquid 0.5 mL/min MeOH and gas 4 mL/ min, and finally liquid 2 mL/min MeOH and gas 1 mL/min 65% of selectivity for Pd-CeS with liquid 1 mL/min and gas 4 mL/ min). Moreover, the same maximum production rate of H2O2 around 3 μmol/min for Pd-CeS, Pd-ZS, and Pd-Z was achieved with different liquid and gas flow rates. Continuous operation and reactor technology play important roles in this green synthesis: optimization of gas and liquid flow rates and contact time between the liquid and the solid (catalysts) phase lead to a dramatic selectivity improvement in a continuous reactor, raising the value obtained in the semibatch reactor from 30% to 70%.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107443

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8875-8882

Titre :	Three – dimensional water vapor visualization in porous packing by near - infrared diffuse transmittance tomography
Type de document :	texte imprimé
Auteurs :	Méabh Nic An tSaoir, Auteur ; Daniel Luis Abreu Fernandes, Auteur ; Jacinto Sá, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8875-8882
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Tomography Water vapor
Résumé :	This work presents a procedure based on two-dimensional and three-dimensional spatially resolved near-infrared imaging to observe temperature and composition maps in gas―solid packed beds subjected to effects of aspect ratio and nonisothermal conditions. The technique was applied to the water vapor flow in a fluidized bed and a packed bed reactor and confirmed uneven water vapor flow channeling and temperature distributions in the core packed bed and in the vicinity of the wall due to flow maldistribution. In addition, the heat uptake and local cross-mixing were experimentally ascertained.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107442

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8867–8874

Titre :	Assessment and modeling of a sequential process for water treatment — adsorption and batch CWAO regeneration of activated carbon
Type de document :	texte imprimé
Auteurs :	Carine Julcour-Lebigue, Auteur ; Nguessan Joaquim Krou, Auteur ; Caroline Andriantsiferana, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8867–8874
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Sequential process Adsorption Carbon
Résumé :	A new sequential process, AD–OX, for (post)treatment of water polluted by poorly biodegradable organic compounds has been investigated. It is based on hybridizing classical adsorption on a fixed bed of activated carbon (AC) followed by batch wet catalytic oxidation at higher temperature and pressure on the same bed of AC, which is then regenerated in situ. The basic idea is to take advantage of both operations: 1-efficient water purification at room temperature by adsorption, 2-effective concentrated pollutant degradation by batch air oxidation achieving simultaneously AC regeneration. A small fixed bed reactor, 10 mm diameter, 0.18 m long, filled with granular activated carbon and equipped with convenient 3-way valves, may achieve successively the two main steps. Several AD–OX cycles have been performed with a phenol solution to quantify the regeneration of the activated carbon adsorption capacity. Results show that activated carbon is quickly damaged during the first cycles, due to oxidative coupling, but then a quasi-steady state is obtained proving that significant oxidative regeneration has been achieved. A dynamic model of the adsorption step has been first developed, including intraparticle diffusion, liquid–solid external mass transfer, and axial dispersion of the liquid phase. It has been applied to simulate the performance of the regenerated activated carbon. Using oxidation kinetics over this aged carbon and its adsorption isotherm, separately determined in an autoclave at reaction temperature, the oxidation step after several cycles has been simulated including the heating period, where desorption and oxidation simultaneously occur. The proposed model conveniently predicts the complex phenol concentration–time profile and gives insight to the hydrodynamic behavior of the recycle reactor and the role of mass transfer resistances.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie2020312

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8858-8866

Titre :	Modeling of a three - phase continuously operating isothermal packed - bed reactor : Kinetics, mass - transfer, and dispersion effects in the hydrogenation of citral
Type de document :	texte imprimé
Auteurs :	Teuvo Kilpio, Auteur ; Paivi Maki-Arvela, Auteur ; Mats Ronnholm, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8858-8866
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Hydrogenation Dispersion Mass transfer Kinetics Fixed bed reactor Modeling
Résumé :	A continuously operating isothermal dynamic packed-bed reactor was modeled. The model included chemical reaction, gas―liquid mass transfer, convection, axial dispersion, pore diffusion, and catalyst deactivation. The model was solved by using the method of lines. The model was applied on experimental data from citral hydrogenation over a supported nickel catalyst. The experiments had been carried out at 25―65 °C and at 6.1 bar in a laboratory-scale trickle-bed reactor (d = 1 cm; L = 5 cm). The parameters in the model were the rate constants, pore diffusivity, coking rate constant, Pedet number, and gas―liquid mass-transfer coefficient. A sensitivity study was performed to reveal how much a change in each of these changed the product concentration trend. The simulations revealed that the gas―liquid mass-transfer coefficient and effective diffusivity should have been well below expected values to significantly reduce the productivity. The gas-liquid mass transfer and pore diffusion were not rate-limiting; because hydrogen was used in excess, particles were small and the system was dilute. The citral concentration-dependent deactivation model based on site competition was able to describe the observed activity decline. Parameter estimation for the reaction rate and coking rate was carried out. A reasonable agreement with the experimental trends was obtained. An estimate of the Peclet number was obtained from step-response measurements with an inert tracer, which revealed that the reactor did not operate completely as a plug-flow unit. The model described here can be extended to be applicable for other hydrogenation and oxygenation reactions of other fine chemicals.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107440

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp 8849–8857

Titre :	Upgrading of fischer – tropsch waxes by fluid catalytic cracking
Type de document :	texte imprimé
Auteurs :	David Kubicka, Auteur ; Radek Cerny, Auteur
Année de publication :	2012
Article en page(s) :	pp 8849–8857
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Fluid catalytic
Résumé :	Synthesis gas originating from alternative feedstocks such as biomass, coal, or natural gas can become an important source of hydrocarbon-based automotive fuels in the future. Fischer–Tropsch synthesis (FTS) affords these hydrocarbons, but upgrading of the primary FTS products is unavoidable. One option is to use the fluid catalytic cracking (FCC) process to convert FTS waxes into a wide range of products. To investigate the impact of FTS wax addition to a conventional FCC feedstock on product yields and properties, microactivity test (MAT) experiments were performed. The tests were performed at 803 K and the catalyst to feed ratio (C/F) was varied in the range 2–4 m/m. The feed contained 0–100% of FTS wax. The addition of FTS wax resulted in increased conversion and yield of the middle distillate fraction (light cycle oil, LCO) and decreased yield of coke. Owing to the increased conversion, higher yields of propylene were obtained by catalytic cracking of feedstocks containing FTS wax. The detailed GC analysis of the products indicated enhanced properties of LCO due to the lowered content of aromatics.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie201969s

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8840-8848

Titre :	Stable steam reforming of ethanol in a two - zone fluidized - bed reactor
Type de document :	texte imprimé
Auteurs :	L. Pérez-Moreno, Auteur ; J. Soler, Auteur ; J. Herguido, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8840-8848
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Fluidized bed reactor Steam reforming
Résumé :	The oxidative steam reforming of ethanol in a two-zone fluidized-bed reactor (TZFBR) and in a conventional fluidized-bed reactor over a Ni/Al2O3 catalyst has been investigated. Catalyst deactivation has been studied for both contact modes. Coke generation has been verified by several techniques, and a stable performance was obtained in the TZFBR, where coke formation was counteracted with continuous catalyst regeneration. The effects of the main operating variables (steam/ethanol ratio S/E, oxygen/ethanol ratio O/E, temperature, and relative velocity with respect to the minimum fluidization velocity) have been studied. Both stable results and continuous operation without catalyst deactivation were achieved in the TZFBR in a wide range of S/E values, showing its viability for carrying out this process. High hydrogen selectivity with total conversion of ethanol was achieved even at low S/E and O/E ratios.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107438

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8835–8839

Titre :	Comparison of gas – liquid–liquid – solid four - phase trickle - bed reactor with upflow reactor under high liquid flow rate
Type de document :	texte imprimé
Auteurs :	Hiroshi Yamada, Auteur ; Yoshiro Ohashi, Auteur ; Tomohiko Tagawa, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8835–8839
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Gas liquid
Résumé :	The hydrogenation of carbobenzoxy phenylalanine was investigated in order to better understand the influence of mass transfer effects in four-phase fixed-bed reactor systems. In this reaction, the carbobenzoxy phenylalanine is dissolved in an organic solvent and is reacted with a gas in the presence of a hydrophilic catalyst (Pd/Al2O3). An aqueous phase is also required to dissolve the reaction product, leading to a four-phase gas–liquid–liquid–solid system. Results indicate that higher liquid flow rates lead to faster rates of reaction due to improved contact efficiency between the organic phase and catalyst. Similar performance was observed through experiment and modeling in two fixed-bed reactor configurations (trickle-bed reactor and gas–liquid cocurrent upflow reactor) at higher liquid flow rates.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie201966j

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8826–8834

Titre :	Catalytic and photocatalytic oxidation of aqueous bisphenol a solutions : Removal, toxicity, and estrogenicity
Type de document :	texte imprimé
Auteurs :	Mirjana Bistan, Auteur ; Tatjana Tisler, Auteur ; Albin Pintar, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8826–8834
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Catalytic Oxidation Bisphenol
Résumé :	Catalytic wet-air oxidation (CWAO) of aqueous solutions of bisphenol A (BPA) was investigated in a trickle-bed reactor at temperatures up to 230 °C and oxygen partial pressure of 10.0 bar over TiO2 and Ru/TiO2 solids. It was observed that in the given range of operating conditions BPA undergoes both noncatalyzed and catalyzed oxidation routes. The employed Ru/TiO2 catalyst containing 3.0 wt % of metallic phase enabled complete removal of BPA and more than 96% of TOC removal at temperatures of 200 °C and above. No catalyst deactivation occurred that could be attributed to the dissolution of active ingredient material. At these conditions, no carbonaceous deposits were accumulated on the catalyst surface. The acute toxicity of end-product solutions to organisms from different taxonomic groups and estrogenicity determined by the genetically modified yeast, compared with those of the feed solutions, was significantly reduced by CWAO treatment over the Ru/TiO2 catalyst. For comparison, oxidative destruction of BPA was also investigated in this study by means of either photolytic or heterogeneous photocatalytic oxidation. A commercial TiO2 photocatalyst illuminated by UV light enabled complete removal of BPA; however, lower decrease of toxicity and estrogenicity in the treated solution was observed.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie201957z

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8815-8825

Titre :	Selective hydrogenation of 1 - heptyne in a mini trickle bed reactor
Type de document :	texte imprimé
Auteurs :	Mansour Al-Herz, Auteur ; Mark J. H. Simmons, Auteur ; Joseph Wood, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8815-8825
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Trickle bed reactor Hydrogenation
Résumé :	The selective hydrogenation of 1-heptyne over a 2 wt % Pd/Al2O3 catalyst was studied in a trickle bed reactor operating in both batch recycle and continuous modes. The reaction was studied in a range of different solvents, including isopropanol, hexane, mixtures of these two solvents, and also isopropanol with small quantities of water and base (NaOH) added. It was found that the rate of reaction was fastest in hexane, owing to the higher hydrogen solubility in this solvent. However, the selectivity toward 1-heptene was higher in isopropanol, with over 95% selectivity being maintained for 120 min of the total 240 min reaction time. The addition of water or base led to an increase in reaction rate, possibly through modification of the adsorption equilibria at the catalyst surface or direct involvement in the reaction. The hydrodynamics of trickle flow upon the reaction were investigated, showing that increasing liquid flow rate led to enhancement of reaction rate, although a plateau was eventually reached at the higher flows. The higher flows led to improved catalyst wetting, liquid hold up, and mass transfer rates, thus explaining the enhanced reaction rate. The concentration profiles were fitted according to a Langmuir―Hinshelwood kinetic expression. Operation in continuous flow was demonstrated, although a long residence time was required for high conversion, leading to lower 1-heptene selectivity compared with batch recycle operation.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107435

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8806-8814

Titre :	Polymer anchored catalysts for oxidation of styrene using TBHP and molecular oxygen
Type de document :	texte imprimé
Auteurs :	Sweta Sharma, Auteur ; Shishir Sinha, Auteur ; Shri Chand, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8806-8814
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Oxidation Catalyst
Résumé :	Catalytic oxidation of styrene was investigated for polymer anchored Cu(II) and Mn(II) complexes prepared by Schiff base tridentate ligand. The effect of different oxidants, tert-butyl hydroperoxide (TBHP) under atmospheric pressure and molecular oxygen (O2) at high pressure in a batch reactor, were studied for maximum conversion of styrene and selectivity of styrene oxide product. The effect of various reaction parameters such as temperature, styrene to TBHP mole ratio, and catalyst amount were studied using TBHP as oxidant. The maximum conversion of styrene (87.3%) was obtained using Cu(II) complex, with maximum selectivity to styrene oxide (76.2%) at styrene to TBHP mole ratio of 1:3, 70 °C, and 25 mg catalyst The O2 oxidant showed maximum conversion of 45.5% at 80 °C and 0.5 MPa pressure, with a styrene oxide selectivity of 22.4%. The catalytic activity was improved to 70.0% by addition of TBHP as initiator during the use of O2 oxidant. The Cu(II) catalyst showed better catalytic activity in comparison to Mn(II) catalyst using both TBHP and O2 oxidant.
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107434

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8796–8805

Titre :	Sorption - enhanced reforming of ethanol over Ni - and Co - incorporated MCM - 41 type catalysts
Type de document :	texte imprimé
Auteurs :	Seval Gunduz, Auteur ; Timur Dogu, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8796–8805
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Sorption Ethanol Catalysts
Résumé :	Ni- and Co-incorporated MCM-41 type mesoporous materials with Ni/Si and Co/Si molar ratios of 0.12 were synthesized, characterized, and tested in both steam reforming of ethanol (SRE) and sorption-enhanced steam reforming of ethanol (SESRE) reactions. Characterization results showed that Co and Ni were successfully incorporated and well-dispersed in the mesoporous MCM-41 support. Ni- and Co-incorporated MCM-41 catalysts had surface area values of 449.0 and 303.6 m2/g, respectively. They also had narrow pore size distributions, with average pore diameters of 2.2 and 1.98 nm, respectively. SESRE results obtained with these catalysts showed that in situ capture of CO2 during ethanol reforming reaction significantly enhanced hydrogen yield in the temperature range of 500–600 °C. The catalytic performance of Ni-incorporated MCM-41 was much better than the Co-incorporated MCM-41, in hydrogen production by ethanol reforming. The highest hydrogen yield value obtained over the Ni-incorporated MCM-41 catalyst was achieved at 600 °C as 5.6 in SESRE reaction. This was 94% of the maximum possible hydrogen yield value of 6.0.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie201852f

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8788–8795

Titre :	Effects of sorption enhancement and isobutene formation on etherification of glycerol with tert - butyl alcohol in a flow reactor
Type de document :	texte imprimé
Auteurs :	Nalan Ozbay, Auteur ; Nuray Oktar, Auteur ; Gulsen Dogu, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8788–8795
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Isobutene Glycerol Flow reactor
Résumé :	In the presented work, liquid phase etherification reaction of glycerol (G) with tert-butyl alcohol (TBA) was investigated in a continuous flow reactor using Amberlyst-15 (A-15) as the catalyst. Some experiments were also repeated in a batch reactor at autogenous pressure. Effects of feed composition, reaction temperature (70–110 °C), and reaction pressure (1–5 bar) on the product distribution were investigated. When flow reactor pressure was reduced from 5 to 1 bar, enhanced glycerol conversion and isobutene formation were observed. Conversion of glycerol reached 66% at 110 °C, at a space time of 18 s·g·cm–3. However, batch reactor results indicated glycerol conversion values over 90% with diether selectivity of about 36% at much longer reaction times, over 400 min. Results indicated significance of equilibrium limitations, which initiated the idea of performing sorption enhanced reaction experiments in the flow reactor using Zeolite 4A and 5A as water adsorbents. Results of these sorption enhanced reactor experiments proved significant enhancement of glycerol conversion and diether yield by in situ removal of produced water during the etherification reaction. Among these two adsorbents, performance of Zeolite 4A was better. Diether selectivity increased from about 0.20 to values over 0.33 in the sorption enhanced reactor experiments performed with a zeolite/catalyst ratio of 4/1 at 90 °C.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie201720q

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8777–8787

Titre :	Biodiesel process intensification by using static mixers tubular reactors
Type de document :	texte imprimé
Auteurs :	E. Santacesaria, Auteur ; R. Turco, Auteur ; M. Tortorelli, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8777–8787
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Biodiesel process
Résumé :	Biodiesel is usually produced by reacting triglycerides, contained in vegetable oils, with methanol in the presence of KOH, NaOH, or related alkoxides as catalysts. In industry, the reaction is performed in stirred tank reactors and requires 1–2 h of reaction time being the reaction rate strongly affected by mass transfer limitation. We have recently shown, by using a Corrugated Plates Heat Exchanger Reactor, that a very high productivity (about 2 tons/day L) can be obtained by working at 60–100 °C thanks to the presence of an intense local “micromixing”. Moreover, we have recently tested the performances obtained in a tubular reactor filled with stainless steel spheres of different diameters. By opportunely changing the spheres diameters it is possible to obtain microchannels in a range of 300–1000 μm with an intense local micromixing. Again, thanks to micromixing we obtained very high productivities. However, in these last reactors the void portion of the reactor is low and the productivity per overall reactor volume is relatively low. It is possible to obtain better results, in terms of productivity, by filling the tubular reactor with stainless steel wool, being in this case the void fraction about 0.9. In the present work, some of the mentioned systems will be compared for their performances by using different amounts of KOH as catalyst (1 or 2% b.w. of oil). A dramatic change in biodiesel yield has been observed in all cases passing from 1 to 2% of catalyst independently of the reactants flow rate. These behaviors cannot be interpreted with the pseudomonophasic kinetic models, normally reported in the literature. At this purpose, for interpreting all the observed kinetic behaviors a new biphasic kinetic model, based on a reliable catalytic mechanism, has been developed. This model has been applied, first of all, to data reported in the literature related to runs performed in batch conditions with the scope of estimating the kinetic parameters, and then it has been applied to all the runs performed in continuous reactors with a satisfactory agreement.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie201640w

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8768–8776

Titre :	Glycerol chlorination in gas – liquid semibatch reactor : An alternative route for chlorohydrins production
Type de document :	texte imprimé
Auteurs :	R. Tesser, Auteur ; M. Di Serio, Auteur ; R. Vitiello, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8768–8776
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Gas liquid Chlorohydrins production
Résumé :	In the present paper, an alternative synthetic way to obtain chlorohydrins, that are commercial products from glycerol feedstock, is presented. This synthetic route to transform glycerol into these high-value chemicals involves the use of gaseous HCl and glycerol in the presence of a carboxylic acid, as catalyst, in order to obtain, as main product, αγ-dichlorohydrin. Monochlorohydrins are also obtained as intermediates reaction products. As shown in a previous work some catalysts are selective in the production of the desired product, while others give monochlorohydrins as the main products. We attempted to correlate the selectivity shown by different carboxylic acids to their pKa, but this correlation seems not of general validity and it still remains a problem to correlate the catalytic behavior with the molecular structure of the catalyst. At this purpose, in this work we have investigated the behavior of a homologous chlorinated series of catalysts, such as the following: acetic, monochloroacetic, dichloroacetic, and trichloroacetic acid, focusing in particular the attention on both activity and selectivity shown by each catalyst. A kinetic model, based on a reliable mechanism, developed in a previous work but implemented for the HCl gas–liquid partition has been used for interpreting all the kinetic runs. Then, the obtained kinetic constants have been elaborated by using the Taft equation in the attempt to correlate chemical structure of the catalyst and the activity.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie201629z

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8760–8767

Titre :	Biphasic model describing soybean oil epoxidation with H2O2 in continuous reactors
Type de document :	texte imprimé
Auteurs :	E. Santacesaria, Auteur ; A. Renken, Auteur ; V. Russo, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8760–8767
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Biphasic Continuous reactors
Résumé :	Epoxidized soybean oil (ESBO) is produced in industry by reacting soybean oil, at 60–70 °C, with hydrogen peroxide in the presence of formic or acetic acid. A small amount of sulphuric or phosphoric acid is necessary to catalyze the oxidation of the carboxylic acid to the corresponding per-carboxylic acid. Per-carboxylic acid, formed in situ, migrates from the aqueous phase to the oil phase where it spontaneously reacts with the double bonds to give an oxirane ring. This reaction is extremely exothermic (ΔH = −55 kcal/mol) and must be kept under thermal control. Two undesired side reactions can occur: the oxirane ring-opening and the hydrogen peroxide decomposition. In a previous work, a biphasic kinetic model for describing the epoxidation of soybean oil in fed or pulse-fed-batch reactors has been developed and the parameters of the model have been determined by mathematical regression analysis. In the present paper, the model has been adapted to simulate also kinetic runs performed in two continuous tubular reactors of different sizes, filled with spheres of stainless steel (AISI 316) used as static mixer. The agreement found, in simulating the continuous runs, validates the developed biphasic kinetic model. This model constitutes a valid base for the design of a continuous process and for promoting the process intensification.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie2016174

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8742–8747

Titre :	Regulation of Catalytic Reaction via Vapor-Phase Condensation. 2. : Operational Realization in a Two-Stage Reactor
Type de document :	texte imprimé
Auteurs :	Si-Cao Wu, Auteur ; Zhen-Min Cheng, Auteur ; Peng Liu, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8742–8747
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Regulation catalytic reaction Vapor phase
Résumé :	A two-stage reactor composed of a slurry bubble column and a fixed bed was proposed. The slurry column, installed with a radio frequency conductance liquid level controller, was considered not only as a preliminary reactor for the vaporization of the liquid reactants, but also as a protector to prevent liquid flooding in the fixed bed. Preliminary experiments were carried out to investigate the effects of different operating factors on the reactor performance, and the results showed that even under the optimal condition the benzene concentration should be kept at a low level of 21.9% to avoid high temperature rise. Therefore, side stream injection of cyclohexane into the fixed bed was proposed, and benzene conversion of 99.82% was reached even at a much higher concentration of 32.8%. To verify whether capillary condensation inside the catalyst particle in the fixed bed would exist in the presence of coolant injection, a criterion was proposed which is based on the understanding that once vapor condensation is occurring it will lead to multiplicity in reaction rate, which will consequently result in hysteresis in temperature profile under adiabatic condition.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie2019036

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8735–8741

Titre :	Regulation of catalytic reaction via vapor - phase condensation. 1. : Experimental study on the reaction rate hysteresis loops
Type de document :	texte imprimé
Auteurs :	Ye-Mao Yu, Auteur ; Zhen-Min Cheng, Auteur ; Zhi-Ming Zhou, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8735–8741
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Regulation catalytic reaction
Résumé :	To experimentally verify the existence of reaction rate hysteresis in the gas phase operation due to capillary condensation, benzene hydrogenation was carried out in a fixed bed under isothermal condition. Through changing the flow rate of benzene and cyclohexane mixture in a sequence from low to high and then vice versa, a group of distinctive conversion profiles was obtained. By plotting the reaction rate against the relative vapor pressure, hysteresis loops in reaction rate are confirmed to exist. It was observed the reaction rate kept nearly constant in the region of p/p0 < 0.6 and decreased rapidly in the region of p/p0 > 0.8. In providing an intrinsic understanding on the influence of vapor condensation on the reaction rate of a partially wetted catalyst, the reaction rate and internal effectiveness factor are plotted against the catalyst wetting fraction, from which a new correlation between the overall reaction rate and catalyst wetting fraction was proposed.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie201901z

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp 8726–8734

Titre :	CO2 Sequestration in chrysotile mining residues — implication of watering and passivation under environmental conditions
Type de document :	texte imprimé
Auteurs :	Gnouyaro P. Assima, Auteur ; Faïçal Larachi, Auteur ; Georges Beaudoin, Auteur
Année de publication :	2012
Article en page(s) :	pp 8726–8734
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Chrysotile Mining Residues
Résumé :	Factors affecting carbon dioxide fixation in chrysotile mining residues (CMR) under environmental conditions were studied by reproducing mineral dissolution and carbonation in laboratory columns packed with CMR particles. Carbonation is very sensitive to water saturation and watering frequency of the CMR porous media. CO2 uptake by dry residues subjected to dry CO2 flow for several days at ambient temperature was below 0.02%. However, an increase by a factor of 20 in CO2 uptake was achieved by periodic addition of small amounts of water with respect to a moistened CO2 stream over dry CMR samples. The highest MgCO3 conversion resulted in nearly 22 mg of CO2 captured per gram of residue, revealing that up to 93% of Mg remained noncarbonated because of surface obstructing processes. Magnesium leaching from CMR was hindered by two concomitant passivation phenomena limiting the residue’s CO2 storage capacity. A unique cyclic voltammetry technique using oxic and anoxic aqueous solutions contacted with CMR fixed beds was implemented to assess the relative importance from CMR-borne iron electrochemical passivation and silica-deposit nonelectrochemical passivation. Passivation around the dissolving CMR particles by iron hydroxide precipitation was found to develop very rapidly in comparison to silica gel polymerization.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie202693q

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8719–8725

Titre :	Enhancement of the liquid - side mass transfer in a falling film catalytic microreactor by in - channel mixing structures
Type de document :	texte imprimé
Auteurs :	Evgeny V. Rebrov, Auteur ; Thijs Duisters, Auteur ; Patrick Lob, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8719–8725
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Mass transfer Microreactor
Résumé :	Catalytic octanal oxidation with oxygen was performed at 100 °C and the total pressure of 5 and 10 bar in a falling film microreactor with varying reaction plates bearing different in-channel mixing structures. The liquid flow rate was changed in the range of 3.3–17.5 mL/min. The liquid-sided mass transfer over grooved or finned structured plates was enhanced by factors of 1.12 and 1.20, respectively, compared to that on a standard plate with 16 microchannels with dimensions of 1200 μm × 400 μm. The liquid flow rate over the structured plates could be increased by 60%–80% without any loss of octanal conversion. A two-dimensional convection and diffusion model adopted from Al-Rawashdeh et al. [Chem. Eng. Sci. 2008, 63, 5149] was formulated to simulate the reactor behavior, and its predictions describe the experimental results in terms of octanal conversion with an accuracy of 4.3% when the actual temperature distribution in the reactor plate is taken into account.
ISSN :	0888-5885
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie301058h

[article]
in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8711-8718

Titre :	Corrosion behavior of carbon steel in alkanolamine /room - temperature ionic liquid based CO2 capture systems
Type de document :	texte imprimé
Auteurs :	Muhammad Hasib-ur-Rahman, Auteur ; Hana Bouteldja, Auteur ; Pascal Fongarland, Auteur
Année de publication :	2012
Article en page(s) :	pp. 8711-8718
Note générale :	Industrial chemistry
Langues :	Anglais (eng)
Mots-clés :	Carbon dioxide Ionic liquid Carbon steel Corrosion
Résumé :	To address the drawbacks of aqueous alkanolamine based state-of-the-art technology for industrial scale carbon dioxide capture, among a number of options, alkanolamine/room-temperature ionic liquid (RTIL) systems are also being tested as a likely replacement. These new schemes seem to be a better alternative to hamper corrosion occurrence. Omission of the aqueous phase marks abolition of probable oxidizing species mainly responsible for corrosion in water-based chemical absorption processes. In the present study, the corrosion phenomenon in amine/room-temperature ionic liquid blends comprised of alkanolamine/s (monoethanolamine, 2-amino-2-methyl-1-propanol, diethanolamine, N-methyldiethanolamine) and hydrophilic room-temperature ionic liquid ([BMIM][BF4], [EMIM][BF4], and [EMIM][Otf]) has been investigated by systematically probing the effect of amine/RTIL type, process temperature, CO2 loading, presence/absence of oxygen in flue gas, as well as the influence of water content. The analytical techniques exercised in this regard include linear polarization resistance (LPR), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX).
ISSN :	0888-5885
En ligne :	http://cat.inist.fr/?aModele=afficheN&cpsidt=26107423

Industrial & engineering chemistry research / Paul, Donald R. . Vol. 51 N° 26

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