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Vol. 49 N° 12 - Juin 2010 [texte imprimé] . - 2010 . - p. 5489-5958 : ill. ; 28 cm. Chemical engineering Langues : Français (fre)
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Ajouter le résultat dans votre panierCoupling between membrane processes and crystallization operations / Catherine Charcosset in Industrial & engineering chemistry research, Vol. 49 N° 12 (Juin 2010)
Titre : Coupling between membrane processes and crystallization operations Type de document : texte imprimé Auteurs : Catherine Charcosset, Auteur ; Roland Kieffer, Auteur ; Denis Mangin, Auteur Année de publication : 2010 Article en page(s) : pp. 5489–5495 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Couple membrane processes Crystallization operations Résumé : The ability to couple membrane processes and crystallization operations, in order to develop efficient crystallization technologies, is increasingly reported. The main features of membrane crystallization systems are (1) to control and limit the maximum level of supersaturation due to defined mass transfer across the membrane; (2) to act as a support able to activate heterogeneous nucleation; (3) to control solid features such as size, shape, polymorphic form, and purity; and (4) to reduce energy consumption. To achieve these goals, several membrane techniques are used: reverse osmosis, membrane distillation, membrane contactor, and membrane templates. This review describes briefly the principles, applications, and advantages and drawbacks of each technique for crystallization operations. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901824x
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5489–5495[article] Coupling between membrane processes and crystallization operations [texte imprimé] / Catherine Charcosset, Auteur ; Roland Kieffer, Auteur ; Denis Mangin, Auteur . - 2010 . - pp. 5489–5495.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5489–5495
Mots-clés : Couple membrane processes Crystallization operations Résumé : The ability to couple membrane processes and crystallization operations, in order to develop efficient crystallization technologies, is increasingly reported. The main features of membrane crystallization systems are (1) to control and limit the maximum level of supersaturation due to defined mass transfer across the membrane; (2) to act as a support able to activate heterogeneous nucleation; (3) to control solid features such as size, shape, polymorphic form, and purity; and (4) to reduce energy consumption. To achieve these goals, several membrane techniques are used: reverse osmosis, membrane distillation, membrane contactor, and membrane templates. This review describes briefly the principles, applications, and advantages and drawbacks of each technique for crystallization operations. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901824x Exemplaires
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Titre : Integrated biological and electrochemical oxidation treatment for high toxicity pesticide pollutant Type de document : texte imprimé Auteurs : Lei Liu, Auteur ; Guohua Zhao, Auteur ; Yaning Pang, Auteur Année de publication : 2010 Article en page(s) : pp. 5496–5503 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : integrated biological oxidation Electrochemical Toxicity pesticide Résumé : A novel integrated biological and electrochemical oxidation (BEO) process was proposed for the treatment of biorefractory pesticide wastewater with high toxicity. An acetamiprid solution of 1000 mg L−1 was used as the target pollutant. Its biodegradability in terms of biochemical oxygen demand in a 5-d test period (BOD5)/total organic carbon (TOC) was only 0.0057, presenting its high biorefractory property. In the BEO system with boron-doped diamond electrode (BDD), the value of BOD5/TOC was improved to 1.17 and the toxicity was reduced by 40% in 3 h, maintaining the activity of microorganisms on a biofilter at an appropriate level. The intermediates (mainly small molecule carboxylic acids) produced in the electrochemical process served as nutrients for the microorganisms and then were biodegraded, while the biodegradation of these intermediates further enhanced the electrochemical oxidation of the original pollutant. The synergy of electrochemical and biological processes improved the removal of acetamiprid and TOC with higher efficiency and lower energy consumption. For the same TOC removal, the mineralization current efficiency (MCE) in the BEO was at least 40% higher than that in a single electrochemical oxidation (EO), and the energy consumption was only 53.3 (kW h)/m3 in the BEO in 5 h, which was 44.5% lower than that in the EO. The BEO technique is an efficient method for the treatment of highly concentrated and biorefractory wastewater. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100333v
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5496–5503[article] Integrated biological and electrochemical oxidation treatment for high toxicity pesticide pollutant [texte imprimé] / Lei Liu, Auteur ; Guohua Zhao, Auteur ; Yaning Pang, Auteur . - 2010 . - pp. 5496–5503.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5496–5503
Mots-clés : integrated biological oxidation Electrochemical Toxicity pesticide Résumé : A novel integrated biological and electrochemical oxidation (BEO) process was proposed for the treatment of biorefractory pesticide wastewater with high toxicity. An acetamiprid solution of 1000 mg L−1 was used as the target pollutant. Its biodegradability in terms of biochemical oxygen demand in a 5-d test period (BOD5)/total organic carbon (TOC) was only 0.0057, presenting its high biorefractory property. In the BEO system with boron-doped diamond electrode (BDD), the value of BOD5/TOC was improved to 1.17 and the toxicity was reduced by 40% in 3 h, maintaining the activity of microorganisms on a biofilter at an appropriate level. The intermediates (mainly small molecule carboxylic acids) produced in the electrochemical process served as nutrients for the microorganisms and then were biodegraded, while the biodegradation of these intermediates further enhanced the electrochemical oxidation of the original pollutant. The synergy of electrochemical and biological processes improved the removal of acetamiprid and TOC with higher efficiency and lower energy consumption. For the same TOC removal, the mineralization current efficiency (MCE) in the BEO was at least 40% higher than that in a single electrochemical oxidation (EO), and the energy consumption was only 53.3 (kW h)/m3 in the BEO in 5 h, which was 44.5% lower than that in the EO. The BEO technique is an efficient method for the treatment of highly concentrated and biorefractory wastewater. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100333v Exemplaires
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Titre : Nitration of phenol over a ZSM-5 zeolite Type de document : texte imprimé Auteurs : M. Arshadi, Auteur ; M. Ghiaci, Auteur ; A. Gil, Auteur Année de publication : 2010 Article en page(s) : pp. 5504–5510 Note générale : Chemistry engineering Langues : Anglais (eng) Mots-clés : Liquid phase nitration of phenol Nitric acid Résumé : In this paper, liquid phase nitration of phenol over a solid acid catalyst, ZSM-5 zeolite, was investigated by nitric acid (60%) under various solvent and temperature conditions. The performance of the nitration in ortho and para positions of phenol is suggested to derive from the amount of catalyst and the solvent effects. The loading level of the substrate inside or outside the pores of the zeolite makes the relatively high selectivity to the ortho or para product. However, the experimental results are accounted for by the important role of solvent and the amount of ZSM-5 zeolite in ortho/para selectivity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901862q
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5504–5510[article] Nitration of phenol over a ZSM-5 zeolite [texte imprimé] / M. Arshadi, Auteur ; M. Ghiaci, Auteur ; A. Gil, Auteur . - 2010 . - pp. 5504–5510.
Chemistry engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5504–5510
Mots-clés : Liquid phase nitration of phenol Nitric acid Résumé : In this paper, liquid phase nitration of phenol over a solid acid catalyst, ZSM-5 zeolite, was investigated by nitric acid (60%) under various solvent and temperature conditions. The performance of the nitration in ortho and para positions of phenol is suggested to derive from the amount of catalyst and the solvent effects. The loading level of the substrate inside or outside the pores of the zeolite makes the relatively high selectivity to the ortho or para product. However, the experimental results are accounted for by the important role of solvent and the amount of ZSM-5 zeolite in ortho/para selectivity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901862q Exemplaires
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Titre : High oxygen permeation rate in La0.6Sr0.4Ti0.3Fe0.7O3 thin membrane on a porous support with multichannel structure for CH4 partial oxidation Type de document : texte imprimé Auteurs : Akihiro Kawahara, Auteur ; Yousuke Takahashi, Auteur ; Yuji Hirano, Auteur Année de publication : 2010 Article en page(s) : pp. 5511–5516 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Perovskite oxide Multichannel structure Oxygen permeation rate Résumé : A preparation of La0.6Sr0.4Ti0.3Fe0.7O3 (LSTF) perovskite oxide on a support with a unique multichannel structure achieved a high oxygen permeation rate. A LSTF thin membrane with 60 μm thickness was successfully prepared on the multichannel support with 30% porosity. The oxygen permeation rate was much improved by using the multichannel structured support, as the permeated oxygen was removed rapidly. On the other hand, partial oxidation of CH4 into CO and H2 is dominant on the LSTF membrane. The oxygen permeation rate increased as the thickness of the membrane and the porous support decreased, and a value of 13.3 cm3/(min cm2) was achieved at 1273 K under a CH4 partial oxidation condition. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901874j
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5511–5516[article] High oxygen permeation rate in La0.6Sr0.4Ti0.3Fe0.7O3 thin membrane on a porous support with multichannel structure for CH4 partial oxidation [texte imprimé] / Akihiro Kawahara, Auteur ; Yousuke Takahashi, Auteur ; Yuji Hirano, Auteur . - 2010 . - pp. 5511–5516.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5511–5516
Mots-clés : Perovskite oxide Multichannel structure Oxygen permeation rate Résumé : A preparation of La0.6Sr0.4Ti0.3Fe0.7O3 (LSTF) perovskite oxide on a support with a unique multichannel structure achieved a high oxygen permeation rate. A LSTF thin membrane with 60 μm thickness was successfully prepared on the multichannel support with 30% porosity. The oxygen permeation rate was much improved by using the multichannel structured support, as the permeated oxygen was removed rapidly. On the other hand, partial oxidation of CH4 into CO and H2 is dominant on the LSTF membrane. The oxygen permeation rate increased as the thickness of the membrane and the porous support decreased, and a value of 13.3 cm3/(min cm2) was achieved at 1273 K under a CH4 partial oxidation condition. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901874j Exemplaires
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Titre : An electron-beam irradiation/catalytic oxidation system for purification of aromatic hydrocarbons/air mixture under practical gas-flow condition Type de document : texte imprimé Auteurs : Teruyuki Hakoda, Auteur ; Akihiko Shimada, Auteur ; Atsushi Kimura, Auteur Année de publication : 2010 Article en page(s) : pp. 5517–5522 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Electron-beam (EB) irradiation/catalytic oxidation system Volatile organic compound Résumé : An electron-beam (EB) irradiation/catalytic oxidation system was developed for the purification of a volatile organic compound (VOC) gas stream under a practical gas flow condition. This system consists of a compact-sized electron accelerator and an ozone decomposition catalyst, which is MnO2. The removal of toluene and/or xylene and their mineralization were examined with and without catalytic oxidation for a gas stream at a flow rate of 500 Nm3 h−1. A combined catalyst bed enhanced the removal of VOCs and the mineralization of VOC and its irradiation organic byproducts. For example, for an initial concentration of 5 ppmv, the removal ratio of toluene and xylene increased from 60% to 91% and from 81% to 91%, respectively, at a dose of 4.4 kGy. The mineralization ratio increased from 42% to 100% by the catalytic treatment at doses higher than 9.3 kGy. Furthermore, the yield of CO2 to COx increased from 52−60% to 83−89% by the catalytic treatment. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100278k
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5517–5522[article] An electron-beam irradiation/catalytic oxidation system for purification of aromatic hydrocarbons/air mixture under practical gas-flow condition [texte imprimé] / Teruyuki Hakoda, Auteur ; Akihiko Shimada, Auteur ; Atsushi Kimura, Auteur . - 2010 . - pp. 5517–5522.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5517–5522
Mots-clés : Electron-beam (EB) irradiation/catalytic oxidation system Volatile organic compound Résumé : An electron-beam (EB) irradiation/catalytic oxidation system was developed for the purification of a volatile organic compound (VOC) gas stream under a practical gas flow condition. This system consists of a compact-sized electron accelerator and an ozone decomposition catalyst, which is MnO2. The removal of toluene and/or xylene and their mineralization were examined with and without catalytic oxidation for a gas stream at a flow rate of 500 Nm3 h−1. A combined catalyst bed enhanced the removal of VOCs and the mineralization of VOC and its irradiation organic byproducts. For example, for an initial concentration of 5 ppmv, the removal ratio of toluene and xylene increased from 60% to 91% and from 81% to 91%, respectively, at a dose of 4.4 kGy. The mineralization ratio increased from 42% to 100% by the catalytic treatment at doses higher than 9.3 kGy. Furthermore, the yield of CO2 to COx increased from 52−60% to 83−89% by the catalytic treatment. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100278k Exemplaires
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Titre : Ammonium polyphosphate with crystalline form V by ammonium dihydrogen phosphate process Type de document : texte imprimé Auteurs : Gousheng Liu, Auteur ; Xinchun Liu, Auteur ; Jianguo Yu, Auteur Année de publication : 2010 Article en page(s) : pp. 5523–5529 Note générale : Chemistry engineering Langues : Anglais (eng) Mots-clés : Ammonium polyphosphate Crystalline form V Condensation water-solubility Résumé : Ammonium polyphosphate (APP) with crystalline form V (APP-V) was prepared through the reaction of ammonium dihydrogen phosphate and urea at high temperature and under dry ammonia atmosphere. Effects such as raw material ratios, ammoniation, condensation temperature, and condensation time were examined. Its water-solubility was tested and compared with those of industrial APP-I and APP-II. FTIR, XRD, and TGA techniques were used to characterize this product. The thermal degradation of APP-V was examined and compared with that of APP-I and APP-II; the molecular structure of this APP-V was speculated and discussed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100453a
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5523–5529[article] Ammonium polyphosphate with crystalline form V by ammonium dihydrogen phosphate process [texte imprimé] / Gousheng Liu, Auteur ; Xinchun Liu, Auteur ; Jianguo Yu, Auteur . - 2010 . - pp. 5523–5529.
Chemistry engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5523–5529
Mots-clés : Ammonium polyphosphate Crystalline form V Condensation water-solubility Résumé : Ammonium polyphosphate (APP) with crystalline form V (APP-V) was prepared through the reaction of ammonium dihydrogen phosphate and urea at high temperature and under dry ammonia atmosphere. Effects such as raw material ratios, ammoniation, condensation temperature, and condensation time were examined. Its water-solubility was tested and compared with those of industrial APP-I and APP-II. FTIR, XRD, and TGA techniques were used to characterize this product. The thermal degradation of APP-V was examined and compared with that of APP-I and APP-II; the molecular structure of this APP-V was speculated and discussed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100453a Exemplaires
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Titre : Determination of the dispersion characteristics of miniaturized coiled reactors with fiber-optic Fourier transform mid-infrared spectroscopy Type de document : texte imprimé Auteurs : Clemens B. Minnich, Auteur ; Frank Sipeer, Auteur ; Lasse Greiner, Auteur Année de publication : 2010 Article en page(s) : pp. 5530–5535 Note générale : Chemistry engineering Langues : Anglais (eng) Mots-clés : Miniaturized coiled reactors Fourier transform Tubular reactor Résumé : A miniaturized modularized tubular reactor setup designed for flexible small-scale experimentation under continuous flow conditions was investigated for its residence time behavior. Studies focused on the question of whether the coil shape of the tubular reactor segments beneficially affects the dispersion behavior of the system by inducing secondary flows in the dispersed plug flow pattern. In the studies, fiber-coupled sensors for the attenuated total reflectance technique were applied to measure concentration profiles of tracer substances by Fourier transform mid-infrared spectroscopy. Sensor flow cells with specifically structured flow geometries were designed in order to reduce the impact on the flow characteristics, and in this context they have proven to be superior to nonstructured flow cells. Quantitative evaluation of the measured spectra yielded good-quality time profiles of the tracer concentration that were subjected to a mathematical approximation with the well-established dispersion model by Taylor and Aris. In accordance with model predictions from literature, the axial dispersion coefficient is drastically reduced in coiled capillaries as compared to the coefficient in the Taylor−Aris case for straight tubes. Depending on the influence of the tube curvature and the flow properties, expressed by the product of the square Dean number and the Schmidt number, the reduction of the axial dispersion coefficient can be by up to a factor of 4. For chemical processes with critical requirements regarding selectivity, this can be of great advantage since the detrimental impact of axial back-mixing is effectively reduced. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901094q
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5530–5535[article] Determination of the dispersion characteristics of miniaturized coiled reactors with fiber-optic Fourier transform mid-infrared spectroscopy [texte imprimé] / Clemens B. Minnich, Auteur ; Frank Sipeer, Auteur ; Lasse Greiner, Auteur . - 2010 . - pp. 5530–5535.
Chemistry engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5530–5535
Mots-clés : Miniaturized coiled reactors Fourier transform Tubular reactor Résumé : A miniaturized modularized tubular reactor setup designed for flexible small-scale experimentation under continuous flow conditions was investigated for its residence time behavior. Studies focused on the question of whether the coil shape of the tubular reactor segments beneficially affects the dispersion behavior of the system by inducing secondary flows in the dispersed plug flow pattern. In the studies, fiber-coupled sensors for the attenuated total reflectance technique were applied to measure concentration profiles of tracer substances by Fourier transform mid-infrared spectroscopy. Sensor flow cells with specifically structured flow geometries were designed in order to reduce the impact on the flow characteristics, and in this context they have proven to be superior to nonstructured flow cells. Quantitative evaluation of the measured spectra yielded good-quality time profiles of the tracer concentration that were subjected to a mathematical approximation with the well-established dispersion model by Taylor and Aris. In accordance with model predictions from literature, the axial dispersion coefficient is drastically reduced in coiled capillaries as compared to the coefficient in the Taylor−Aris case for straight tubes. Depending on the influence of the tube curvature and the flow properties, expressed by the product of the square Dean number and the Schmidt number, the reduction of the axial dispersion coefficient can be by up to a factor of 4. For chemical processes with critical requirements regarding selectivity, this can be of great advantage since the detrimental impact of axial back-mixing is effectively reduced. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901094q Exemplaires
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Titre : Catalytic activity in naphthalene reforming of two types of catalytic filters for hot gas cleaning of biomass-derived syngas Type de document : texte imprimé Auteurs : Manfred Nacken, Auteur ; Lina Ma, Auteur ; Steffen Heidenreich, Auteur Année de publication : 2010 Article en page(s) : pp. 5536–5542 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Catalytic filters Naphthalene Résumé : The catalytic activity in the reforming of naphthalene of two different types of catalytic filter candles for biomass-derived syngas cleaning are presented and compared at superficial velocities of 72 and 90 m/h, respectively. The tests were performed in a laboratory setup on a fixed catalyst bed and small sections of full size candles. In a 50 h long-term test of the first candle type of fixed bed design, complete naphthalene conversion was found at 800 °C, 100 ppmv H2S, and an average superficial velocity of 135 m/h for the integrated Ni catalyst. Doubling the naphthalene concentration from 5 to 10 g/Nm3 has also led to complete conversion in a short-term test at a superficial velocity of 90 m/h. Because of easier manufacturing of the second candle type, several candles of a catalytic layer design were prepared by using different MgO-containing support materials and adjusting NiO loadings between 35 and 194 wt %. As compared to previous work, a conversion increase from 58 to 74% was achieved at 800 °C, 100 ppmv H2S, and a superficial velocity of 90 m/h that was further improved to 87% by decreasing the superficial velocity to 72 m/h. In the absence of H2S, 96 or 97% conversion was achieved, respectively. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901428b
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5536–5542[article] Catalytic activity in naphthalene reforming of two types of catalytic filters for hot gas cleaning of biomass-derived syngas [texte imprimé] / Manfred Nacken, Auteur ; Lina Ma, Auteur ; Steffen Heidenreich, Auteur . - 2010 . - pp. 5536–5542.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5536–5542
Mots-clés : Catalytic filters Naphthalene Résumé : The catalytic activity in the reforming of naphthalene of two different types of catalytic filter candles for biomass-derived syngas cleaning are presented and compared at superficial velocities of 72 and 90 m/h, respectively. The tests were performed in a laboratory setup on a fixed catalyst bed and small sections of full size candles. In a 50 h long-term test of the first candle type of fixed bed design, complete naphthalene conversion was found at 800 °C, 100 ppmv H2S, and an average superficial velocity of 135 m/h for the integrated Ni catalyst. Doubling the naphthalene concentration from 5 to 10 g/Nm3 has also led to complete conversion in a short-term test at a superficial velocity of 90 m/h. Because of easier manufacturing of the second candle type, several candles of a catalytic layer design were prepared by using different MgO-containing support materials and adjusting NiO loadings between 35 and 194 wt %. As compared to previous work, a conversion increase from 58 to 74% was achieved at 800 °C, 100 ppmv H2S, and a superficial velocity of 90 m/h that was further improved to 87% by decreasing the superficial velocity to 72 m/h. In the absence of H2S, 96 or 97% conversion was achieved, respectively. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901428b Exemplaires
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Titre : Heat capacity, enthalpy of formation, and entropy of methyl carbamate Type de document : texte imprimé Auteurs : Zuo-Xiang Zeng, Auteur ; Xiao-Nan Li, Auteur ; Wei-Lan Xue, Auteur Année de publication : 2010 Article en page(s) : pp. 5543–5548 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Methyl carbamate Heat capacity Résumé : The heat capacity (Cp) of methyl carbamate (MC) was measured with an adiabatic calorimeter. The standard enthalpy of formation (ΔfH0(cr, 298.15 K)) and the standard entropy (S0(cr, 298.15 K)) for MC were determined. Thus, Cp(T) values of MC were obtained for the crystal and liquid forms in the temperature range of 298.15−433.10 K. A quadratic trinomial was used to correlate the data of Cp(T). The enthalpy of fusion of MC was measured using differential scanning calorimetry (DSC), and its sublimation enthalpy was estimated. The gas-phase standard enthalpy of formation (ΔfH0(g, 298.15 K)) of MC was calculated via the method of group contribution developed by Benson. Based on the above data, the values of ΔfH0(cr, 298.15 K) and S0(cr, 298.15 K) of MC were estimated to be −513.57 kJ/mol and 77.1 J mol−1 K−1, respectively. A thermochemical cycle including a reversible reaction was designed to examine the reliability of the estimated values by measuring the equilibrium constant of the reaction. The results showed that the estimated values for MC were acceptable. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9014342
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5543–5548[article] Heat capacity, enthalpy of formation, and entropy of methyl carbamate [texte imprimé] / Zuo-Xiang Zeng, Auteur ; Xiao-Nan Li, Auteur ; Wei-Lan Xue, Auteur . - 2010 . - pp. 5543–5548.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5543–5548
Mots-clés : Methyl carbamate Heat capacity Résumé : The heat capacity (Cp) of methyl carbamate (MC) was measured with an adiabatic calorimeter. The standard enthalpy of formation (ΔfH0(cr, 298.15 K)) and the standard entropy (S0(cr, 298.15 K)) for MC were determined. Thus, Cp(T) values of MC were obtained for the crystal and liquid forms in the temperature range of 298.15−433.10 K. A quadratic trinomial was used to correlate the data of Cp(T). The enthalpy of fusion of MC was measured using differential scanning calorimetry (DSC), and its sublimation enthalpy was estimated. The gas-phase standard enthalpy of formation (ΔfH0(g, 298.15 K)) of MC was calculated via the method of group contribution developed by Benson. Based on the above data, the values of ΔfH0(cr, 298.15 K) and S0(cr, 298.15 K) of MC were estimated to be −513.57 kJ/mol and 77.1 J mol−1 K−1, respectively. A thermochemical cycle including a reversible reaction was designed to examine the reliability of the estimated values by measuring the equilibrium constant of the reaction. The results showed that the estimated values for MC were acceptable. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9014342 Exemplaires
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Titre : Microreactor performance studies of the cycloaddition of isoamylene and a-methylstyrene Type de document : texte imprimé Auteurs : Obiefuna C. Okafor, Auteur ; Sunitha Tadepalli, Auteur ; Geatesh Tampy, Auteur Année de publication : 2010 Article en page(s) : pp. 5549–5560 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Isoamylene α -methylstyrene Cycloaddition reaction Résumé : The cycloaddition reaction between isoamylene and α-methylstyrene yields indane compounds 1,1,2,3,3,-pentamethylindane and 3-ethyl-1,1,3-trimethylindane, which are intermediate cyclic products used in the synthesis of musk fragrances. This exothermic reaction is usually carried out industrially in large semibatch reactors. The microreactor, with enhanced heat and mass transfer characteristics, was used for the reaction with aqueous sulfuric acid as catalyst. The dependence of reactant conversion, product yield, and average reaction rates on catalyst concentration, temperature, velocity, residence time, and the molar ratio of the reactants in the feed was investigated. A similar study was also performed in the semibatch reactor to compare its performance with that of the microreactor. Higher product yields were obtained in the microreactor, and the average reaction rates in the microreactor were 3 orders of magnitude greater than those obtained in the semibatch reactor. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901794p
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5549–5560[article] Microreactor performance studies of the cycloaddition of isoamylene and a-methylstyrene [texte imprimé] / Obiefuna C. Okafor, Auteur ; Sunitha Tadepalli, Auteur ; Geatesh Tampy, Auteur . - 2010 . - pp. 5549–5560.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5549–5560
Mots-clés : Isoamylene α -methylstyrene Cycloaddition reaction Résumé : The cycloaddition reaction between isoamylene and α-methylstyrene yields indane compounds 1,1,2,3,3,-pentamethylindane and 3-ethyl-1,1,3-trimethylindane, which are intermediate cyclic products used in the synthesis of musk fragrances. This exothermic reaction is usually carried out industrially in large semibatch reactors. The microreactor, with enhanced heat and mass transfer characteristics, was used for the reaction with aqueous sulfuric acid as catalyst. The dependence of reactant conversion, product yield, and average reaction rates on catalyst concentration, temperature, velocity, residence time, and the molar ratio of the reactants in the feed was investigated. A similar study was also performed in the semibatch reactor to compare its performance with that of the microreactor. Higher product yields were obtained in the microreactor, and the average reaction rates in the microreactor were 3 orders of magnitude greater than those obtained in the semibatch reactor. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901794p Exemplaires
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Titre : Oxidative desulfurization of jet and diesel fuels using hydroperoxide generated in situ by catalytic air oxidation Type de document : texte imprimé Auteurs : Ramanathan Sundararaman, Auteur ; Xiaoliang Ma, Auteur ; Chunshan Song, Auteur Année de publication : 2010 Article en page(s) : pp. 5561–5568 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Oxidative desulfurization Diesel fuels Résumé : The objective of this work is to explore the potential of carrying out oxidative desulfurization using air as an oxidant. The liquid fuels to be desulfurized were first contacted with air to produce hydroperoxides in situ, which were then used as selective oxidants to oxidize the sulfur compounds. Unsupported CuO was tested as a catalyst for producing hydroperoxides in the fuel at 120 °C in the presence of air. Air oxidation was also carried out in the presence of Al2O3-supported CuO and also noncatalytically. Unsupported CuO was substantially more active than the other two cases. The yield of the hydroperoxides depends strongly on the catalyst and the reaction temperature; the yield decreased in the order of 120 °C > 140 °C ≫ 100 °C but the rate of oxidation to produce hydroperoxides decreased in the order of 140 °C > 120 °C ≫ 100 °C. It was found that more hydroperoxides could be generated in diesel fuel than in jet fuel, which might be related to the higher concentration of alkyl aromatics in diesel fuel when compared to JP-8 jet fuel. The hydroperoxides generated in situ were then used to oxidize the sulfur compounds in the fuel in the presence of SiO2-supported MoO3 catalyst. Hydroperoxides generated in situ were effective in oxidizing the alkyl-substituted benzothiophene and dibenzothiophene present in jet and diesel fuels to their corresponding sulfones which were then removed by adsorption on beta zeolite. On the other hand, the amount of cumene hydroperoxide required per mole of S for oxidation to sulfone was 1.5 and 10 times higher than the stoichiometric amounts for JP-8 jet fuel and diesel fuel, respectively. This study demonstrates that oxidative desulfurization can be effectively carried out by using air as an oxidant for generating hydroperoxides in situ, which can then be used to selectively oxidize the sulfur compounds to sulfones, thereby eliminating the need for use, storage, and handling of expensive liquid-phase peroxide oxidants. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901812r
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5561–5568[article] Oxidative desulfurization of jet and diesel fuels using hydroperoxide generated in situ by catalytic air oxidation [texte imprimé] / Ramanathan Sundararaman, Auteur ; Xiaoliang Ma, Auteur ; Chunshan Song, Auteur . - 2010 . - pp. 5561–5568.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5561–5568
Mots-clés : Oxidative desulfurization Diesel fuels Résumé : The objective of this work is to explore the potential of carrying out oxidative desulfurization using air as an oxidant. The liquid fuels to be desulfurized were first contacted with air to produce hydroperoxides in situ, which were then used as selective oxidants to oxidize the sulfur compounds. Unsupported CuO was tested as a catalyst for producing hydroperoxides in the fuel at 120 °C in the presence of air. Air oxidation was also carried out in the presence of Al2O3-supported CuO and also noncatalytically. Unsupported CuO was substantially more active than the other two cases. The yield of the hydroperoxides depends strongly on the catalyst and the reaction temperature; the yield decreased in the order of 120 °C > 140 °C ≫ 100 °C but the rate of oxidation to produce hydroperoxides decreased in the order of 140 °C > 120 °C ≫ 100 °C. It was found that more hydroperoxides could be generated in diesel fuel than in jet fuel, which might be related to the higher concentration of alkyl aromatics in diesel fuel when compared to JP-8 jet fuel. The hydroperoxides generated in situ were then used to oxidize the sulfur compounds in the fuel in the presence of SiO2-supported MoO3 catalyst. Hydroperoxides generated in situ were effective in oxidizing the alkyl-substituted benzothiophene and dibenzothiophene present in jet and diesel fuels to their corresponding sulfones which were then removed by adsorption on beta zeolite. On the other hand, the amount of cumene hydroperoxide required per mole of S for oxidation to sulfone was 1.5 and 10 times higher than the stoichiometric amounts for JP-8 jet fuel and diesel fuel, respectively. This study demonstrates that oxidative desulfurization can be effectively carried out by using air as an oxidant for generating hydroperoxides in situ, which can then be used to selectively oxidize the sulfur compounds to sulfones, thereby eliminating the need for use, storage, and handling of expensive liquid-phase peroxide oxidants. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901812r Exemplaires
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Titre : Effect of Mg2+ ions on the nucleation kinetics of calcium sulfate in concentrated calcium chloride solutions Type de document : texte imprimé Auteurs : Baohong Guan, Auteur ; Liuchun Yang, Auteur ; Zhongbiao Wu, Auteur Année de publication : 2010 Article en page(s) : pp. 5569–5574 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Metastable calcium sulfate hemihydrate Nucleation kinetics Résumé : The precipitation kinetics of the metastable calcium sulfate hemihydrate (HH) from aqueous solutions has seldom been addressed. For the first time, the nucleation kinetics of calcium sulfate (probably in α-HH form) in concentrated CaCl2 solutions at 90 °C and the effect of Mg2+ ions were investigated by spontaneous precipitation experiments and a turbidity monitoring method. The results indicate that, at a moderate supersaturation with respect to calcium sulfate, Mg2+ ions retard the nucleation with 0.01 M Mg2+ ions showing the strongest effect; at a higher supersaturation, the inhibition effect decreases when the concentration of Mg2+ ions increases from 0.001 to 0.10 M, and 0.20 M Mg2+ ions show a promoting effect on the precipitation. The interfacial tension values increase with the concentration of Mg2+ ions, resulting in a decrease in nucleation rate in Mg2+ ion-containing solutions compared to Mg2+ ion-free solutions. This may indicate an involvement of Mg2+ ions in the surface reaction during calcium sulfate precipitation. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie902022b
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5569–5574[article] Effect of Mg2+ ions on the nucleation kinetics of calcium sulfate in concentrated calcium chloride solutions [texte imprimé] / Baohong Guan, Auteur ; Liuchun Yang, Auteur ; Zhongbiao Wu, Auteur . - 2010 . - pp. 5569–5574.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5569–5574
Mots-clés : Metastable calcium sulfate hemihydrate Nucleation kinetics Résumé : The precipitation kinetics of the metastable calcium sulfate hemihydrate (HH) from aqueous solutions has seldom been addressed. For the first time, the nucleation kinetics of calcium sulfate (probably in α-HH form) in concentrated CaCl2 solutions at 90 °C and the effect of Mg2+ ions were investigated by spontaneous precipitation experiments and a turbidity monitoring method. The results indicate that, at a moderate supersaturation with respect to calcium sulfate, Mg2+ ions retard the nucleation with 0.01 M Mg2+ ions showing the strongest effect; at a higher supersaturation, the inhibition effect decreases when the concentration of Mg2+ ions increases from 0.001 to 0.10 M, and 0.20 M Mg2+ ions show a promoting effect on the precipitation. The interfacial tension values increase with the concentration of Mg2+ ions, resulting in a decrease in nucleation rate in Mg2+ ion-containing solutions compared to Mg2+ ion-free solutions. This may indicate an involvement of Mg2+ ions in the surface reaction during calcium sulfate precipitation. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie902022b Exemplaires
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Titre : Wet oxidation : an option for enhancing biodegradability of leachate derived from municipal solid waste (MSW) landfill Type de document : texte imprimé Auteurs : Anurag Garg, Auteur ; Alok Mishra, Auteur Année de publication : 2010 Article en page(s) : pp. 5575–5582 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Municipal solid waste Landfill leachateCatalytic wet oxidation (WO) process Résumé : The present study reports the treatment of municipal solid waste (MSW) derived landfill leachate (initial pH = 7.82 and chemical oxygen demand (COD) = 6400 mg L−1) using catalytic wet oxidation (WO) process. The reaction was performed under moderate conditions (110−150 °C temperature and 0.7 MPa total pressures) in the presence of a CuSO4 catalyst. The effect of the promoter (Na2SO3) was also seen on the COD removal. The results were compared with that obtained for Fe2+ and H2O2 combination. Among all tested combinations, (CuSO4 + Na2SO3 + air) exhibited the best performance with ∼90% COD reduction at 150 °C temperature and 0.7 MPa pressures. Under these conditions, the biodegradability of the treated effluent was improved to 0.66 (from an initial value of 0.38). The average oxidation state of carbon (AOSC) value and Fourier transform infrared (FTIR) spectroscopy confirmed the presence of carboxylic acids in the treated effluent. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100003q
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5575–5582[article] Wet oxidation : an option for enhancing biodegradability of leachate derived from municipal solid waste (MSW) landfill [texte imprimé] / Anurag Garg, Auteur ; Alok Mishra, Auteur . - 2010 . - pp. 5575–5582.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5575–5582
Mots-clés : Municipal solid waste Landfill leachateCatalytic wet oxidation (WO) process Résumé : The present study reports the treatment of municipal solid waste (MSW) derived landfill leachate (initial pH = 7.82 and chemical oxygen demand (COD) = 6400 mg L−1) using catalytic wet oxidation (WO) process. The reaction was performed under moderate conditions (110−150 °C temperature and 0.7 MPa total pressures) in the presence of a CuSO4 catalyst. The effect of the promoter (Na2SO3) was also seen on the COD removal. The results were compared with that obtained for Fe2+ and H2O2 combination. Among all tested combinations, (CuSO4 + Na2SO3 + air) exhibited the best performance with ∼90% COD reduction at 150 °C temperature and 0.7 MPa pressures. Under these conditions, the biodegradability of the treated effluent was improved to 0.66 (from an initial value of 0.38). The average oxidation state of carbon (AOSC) value and Fourier transform infrared (FTIR) spectroscopy confirmed the presence of carboxylic acids in the treated effluent. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100003q Exemplaires
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Titre : Fenton pretreatment in the catalytic wet oxidation of phenol Type de document : texte imprimé Auteurs : Aurora Santos, Auteur ; Pedro Yustos, Auteur ; Sergio Rodriguez, Auteur Année de publication : 2010 Article en page(s) : pp. 5583–5587 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Catalytic wet oxidation Phenol (PhOH) aqueous solutions Continuous three-phase reactor FR pretreatment Résumé : Catalytic wet oxidation (CWO) of 1000 mg/L of phenol (PhOH) aqueous solutions has been carried out using a commercial activated carbon as catalyst, placed in a continuous three-phase reactor at 16 bar, and temperature was changed in the interval 127−160 °C. Pure oxygen was fed as gaseous phase. Pollutant conversion, mineralization, intermediate distribution, and toxicity were measured at the reactor exit. The catalyst weight (W) to liquid flow rate (QL) ratio was varied from 0.3 to 17.5 gACmin/mL. Fenton reagent (FR) has been applied to the same phenolic aqueous samples using different amounts of H2O2 (between 10 and 100% of the stoichiometric dose) and 10 mg/L of Fe2+, in a batch way at 50 °C. An integrated process has been proposed that combines FR as pretreatment of the CWO process. In the FR step, 10% of H2O2, 10 mg/L of Fe2+, and reaction times shorter than 40 min are used. Efluent from FR step is fed to the CWO reactor at 127 °C. High mineralization (80−90%) and total detoxification of the effluent was obtained at the reactor exit using W/QL values lower than 10 g·min/mL. Therefore, the FR pretreatment enhances remarkably the efficiency of the CWO at moderate temperature conditions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1004948
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5583–5587[article] Fenton pretreatment in the catalytic wet oxidation of phenol [texte imprimé] / Aurora Santos, Auteur ; Pedro Yustos, Auteur ; Sergio Rodriguez, Auteur . - 2010 . - pp. 5583–5587.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5583–5587
Mots-clés : Catalytic wet oxidation Phenol (PhOH) aqueous solutions Continuous three-phase reactor FR pretreatment Résumé : Catalytic wet oxidation (CWO) of 1000 mg/L of phenol (PhOH) aqueous solutions has been carried out using a commercial activated carbon as catalyst, placed in a continuous three-phase reactor at 16 bar, and temperature was changed in the interval 127−160 °C. Pure oxygen was fed as gaseous phase. Pollutant conversion, mineralization, intermediate distribution, and toxicity were measured at the reactor exit. The catalyst weight (W) to liquid flow rate (QL) ratio was varied from 0.3 to 17.5 gACmin/mL. Fenton reagent (FR) has been applied to the same phenolic aqueous samples using different amounts of H2O2 (between 10 and 100% of the stoichiometric dose) and 10 mg/L of Fe2+, in a batch way at 50 °C. An integrated process has been proposed that combines FR as pretreatment of the CWO process. In the FR step, 10% of H2O2, 10 mg/L of Fe2+, and reaction times shorter than 40 min are used. Efluent from FR step is fed to the CWO reactor at 127 °C. High mineralization (80−90%) and total detoxification of the effluent was obtained at the reactor exit using W/QL values lower than 10 g·min/mL. Therefore, the FR pretreatment enhances remarkably the efficiency of the CWO at moderate temperature conditions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1004948 Exemplaires
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Titre : Simulated dynamic optical response strategy for model identification of metal colloid synthesis Type de document : texte imprimé Auteurs : Roberto Irizarry, Auteur Année de publication : 2010 Article en page(s) : pp. 5588–5602 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Metal spherical particle formation Optical kinetic data colloid synthesis Résumé : A model for metal spherical particle formation is proposed, guided by optical kinetic data of monodisperse metal colloid synthesis. The dynamic optical response of these systems is characterized by broad bands, making their analysis difficult to interpret in terms of particles sizes. To overcome this problem, the data are analyzed in terms of a new strategy called simulated dynamic optical response. Kinetic data were generated using a silver-ethylenediamine complex reduced with isoascorbic acid as a model system. Using this strategy, it was found that autocatalytic formation of primary particles followed by a zone of very fast aggregation mechanism can describe the dominant dynamics during early stages. In later stages, the dominant mechanism switches to slower aggregation modulated by a stability factor. The presented model and identification strategy may be applied to other reaction precipitation systems to produce metal particles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100644h
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5588–5602[article] Simulated dynamic optical response strategy for model identification of metal colloid synthesis [texte imprimé] / Roberto Irizarry, Auteur . - 2010 . - pp. 5588–5602.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5588–5602
Mots-clés : Metal spherical particle formation Optical kinetic data colloid synthesis Résumé : A model for metal spherical particle formation is proposed, guided by optical kinetic data of monodisperse metal colloid synthesis. The dynamic optical response of these systems is characterized by broad bands, making their analysis difficult to interpret in terms of particles sizes. To overcome this problem, the data are analyzed in terms of a new strategy called simulated dynamic optical response. Kinetic data were generated using a silver-ethylenediamine complex reduced with isoascorbic acid as a model system. Using this strategy, it was found that autocatalytic formation of primary particles followed by a zone of very fast aggregation mechanism can describe the dominant dynamics during early stages. In later stages, the dominant mechanism switches to slower aggregation modulated by a stability factor. The presented model and identification strategy may be applied to other reaction precipitation systems to produce metal particles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100644h Exemplaires
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Titre : Denitrification of water with activated carbon-supported metallic catalysts Type de document : texte imprimé Auteurs : Luisa Calvo, Auteur ; Miguel A. Gilarranz, Auteur ; José A. Casas, Auteur Année de publication : 2010 Article en page(s) : pp. 5603–5609 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Nitrates Catalytic reduction Trickle bed reactor Résumé : The catalytic reduction of nitrates with hydrogen in aqueous phase was studied in a trickle bed reactor using different activated carbon-supported metallic catalysts. Continuous experiments were performed at ambient conditions (25 °C and 1 atm) at different space-time values in the range of 25.8−103.3 kgcat h/mol. The activity of monometallic catalysts based on Pd, Rh, Cu, and Ni was low in all the cases, yielding nitrate conversions below 15%. The introduction of a second metal produced a synergistic effect, improving the catalytic activity and the selectivity toward N2. That increase in activity was more pronounced when using Pd or Rh combined with Cu, reaching nitrate conversions above 80% in the case of Pd−Cu catalysts. The catalyst with a Pd/Cu mass ratio of 2:1 (Pd050Cu025) also showed the lowest selectivity to nitrite and the highest to N2. Metal leaching was always below detection limits for Pd and Rh, whereas in the case of Cu and Ni, significant metal concentrations were found in the reaction effluent, the leaching of Ni being higher. The initial pH significantly affected both activity and selectivity of the bimetallic catalysts, the maximum activity being achieved within the 6−7 range, which also led to the lowest Cu leaching. The use of a two-step reaction system was checked using two different catalysts, a bimetallic Pd−Cu in the first and a monometallic Pd catalyst in the second. With this two-step system, an important reduction of the nitrite originating in the first stage was observed, and the formation of N2 at the expense of ammonium was favored. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100838r
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5603–5609[article] Denitrification of water with activated carbon-supported metallic catalysts [texte imprimé] / Luisa Calvo, Auteur ; Miguel A. Gilarranz, Auteur ; José A. Casas, Auteur . - 2010 . - pp. 5603–5609.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5603–5609
Mots-clés : Nitrates Catalytic reduction Trickle bed reactor Résumé : The catalytic reduction of nitrates with hydrogen in aqueous phase was studied in a trickle bed reactor using different activated carbon-supported metallic catalysts. Continuous experiments were performed at ambient conditions (25 °C and 1 atm) at different space-time values in the range of 25.8−103.3 kgcat h/mol. The activity of monometallic catalysts based on Pd, Rh, Cu, and Ni was low in all the cases, yielding nitrate conversions below 15%. The introduction of a second metal produced a synergistic effect, improving the catalytic activity and the selectivity toward N2. That increase in activity was more pronounced when using Pd or Rh combined with Cu, reaching nitrate conversions above 80% in the case of Pd−Cu catalysts. The catalyst with a Pd/Cu mass ratio of 2:1 (Pd050Cu025) also showed the lowest selectivity to nitrite and the highest to N2. Metal leaching was always below detection limits for Pd and Rh, whereas in the case of Cu and Ni, significant metal concentrations were found in the reaction effluent, the leaching of Ni being higher. The initial pH significantly affected both activity and selectivity of the bimetallic catalysts, the maximum activity being achieved within the 6−7 range, which also led to the lowest Cu leaching. The use of a two-step reaction system was checked using two different catalysts, a bimetallic Pd−Cu in the first and a monometallic Pd catalyst in the second. With this two-step system, an important reduction of the nitrite originating in the first stage was observed, and the formation of N2 at the expense of ammonium was favored. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100838r Exemplaires
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Titre : Fabrication and wettability of colloidal layered double hydroxide-containing PVA electrospun nanofibrous mats Type de document : texte imprimé Auteurs : Lina Zhao, Auteur ; Dayong Yang, Auteur ; Mingdong Dong, Auteur Année de publication : 2010 Article en page(s) : pp. 5610–5615 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Colloidal layered double hydroxide/polyvinyl alcohol Résumé : We report a facile protocol of preparing colloidal layered double hydroxide/polyvinyl alcohol (cLDH/PVA) electrospun nanofibrous mats via direct incorporation of low-content cLDH nanoplatelets with PVA without aid of any surfactant. The as-prepared cLDH/PVA nanofibrous mats exhibit a uniform, smooth surface and enhanced temperatures of the onset decomposition and inflection compared with those of the electrospun mats of pristine PVA and solid powdery LDH/PVA (pLDH/PVA) with the same LDH content. Subsequent surface chemical modification enables the resulting cLDH/PVA fibrous mats to exhibit superhydrophobicity and adhesion to water droplets, which are distinctly different from the hydrophilicity of the unmodified cLDH/PVA fibrous mats. Our results involving the cLDH/PVA electrospun nanofibrous mats may allow designing a variety of electrospun composite nanofibers with homogeneous morphology and multiple properties. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie902037z
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5610–5615[article] Fabrication and wettability of colloidal layered double hydroxide-containing PVA electrospun nanofibrous mats [texte imprimé] / Lina Zhao, Auteur ; Dayong Yang, Auteur ; Mingdong Dong, Auteur . - 2010 . - pp. 5610–5615.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5610–5615
Mots-clés : Colloidal layered double hydroxide/polyvinyl alcohol Résumé : We report a facile protocol of preparing colloidal layered double hydroxide/polyvinyl alcohol (cLDH/PVA) electrospun nanofibrous mats via direct incorporation of low-content cLDH nanoplatelets with PVA without aid of any surfactant. The as-prepared cLDH/PVA nanofibrous mats exhibit a uniform, smooth surface and enhanced temperatures of the onset decomposition and inflection compared with those of the electrospun mats of pristine PVA and solid powdery LDH/PVA (pLDH/PVA) with the same LDH content. Subsequent surface chemical modification enables the resulting cLDH/PVA fibrous mats to exhibit superhydrophobicity and adhesion to water droplets, which are distinctly different from the hydrophilicity of the unmodified cLDH/PVA fibrous mats. Our results involving the cLDH/PVA electrospun nanofibrous mats may allow designing a variety of electrospun composite nanofibers with homogeneous morphology and multiple properties. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie902037z Exemplaires
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Titre : Synthesis of faujasite films on carbon fibers and characterization of their sorption properties Type de document : texte imprimé Auteurs : Alexandra Jakob, Auteur ; Valentin Valtchev, Auteur ; Michel Soulard, Auteur Année de publication : 2010 Article en page(s) : pp. 5616–5624 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Faujasite films Carbon fibers Résumé : The ultimate goal of this study is the preparation of materials that prevent organic contamination of satellites in low earth orbit. Carbon fibers were chosen as a substrate because of their light weight and high mechanical resistance, along with a highly accessible surface that could optimize the sorption of the contaminants. Further, the active phase (FAU-type zeolite) was synthesized onto support applying the secondary growth method. The zeolite coatings were crystallized under different conditions in order to control the characteristics of the material. Alkalinity of the initial gel, Si/Al ratio, and synthesis time appear to strongly influence the film characteristics. Thus, highly crystalline FAU-type films with different thicknesses and levels of hydrophilicity were grown. The sorption properties of zeolite films and counterpart powders were investigated by thermogravimetric analyses toward several organic adsorbents (cyclohexane, n-hexane, p-xylene, trimethylbenzene, tetramethoxysilane). The obtained data revealed that the adsorbed quantity of organic species increased with the Si/Al ratio of the zeolite framework due to its increased hydrophobocity. Sorption capacities of the films appeared to be slightly lower than those of their powder counterparts, which was attributed to lower crystal accessibility on zeolite layers. Nevertheless, the set of experimental data demonstrated that the obtained materials are fully conversant with the target application. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901683y
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5616–5624[article] Synthesis of faujasite films on carbon fibers and characterization of their sorption properties [texte imprimé] / Alexandra Jakob, Auteur ; Valentin Valtchev, Auteur ; Michel Soulard, Auteur . - 2010 . - pp. 5616–5624.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5616–5624
Mots-clés : Faujasite films Carbon fibers Résumé : The ultimate goal of this study is the preparation of materials that prevent organic contamination of satellites in low earth orbit. Carbon fibers were chosen as a substrate because of their light weight and high mechanical resistance, along with a highly accessible surface that could optimize the sorption of the contaminants. Further, the active phase (FAU-type zeolite) was synthesized onto support applying the secondary growth method. The zeolite coatings were crystallized under different conditions in order to control the characteristics of the material. Alkalinity of the initial gel, Si/Al ratio, and synthesis time appear to strongly influence the film characteristics. Thus, highly crystalline FAU-type films with different thicknesses and levels of hydrophilicity were grown. The sorption properties of zeolite films and counterpart powders were investigated by thermogravimetric analyses toward several organic adsorbents (cyclohexane, n-hexane, p-xylene, trimethylbenzene, tetramethoxysilane). The obtained data revealed that the adsorbed quantity of organic species increased with the Si/Al ratio of the zeolite framework due to its increased hydrophobocity. Sorption capacities of the films appeared to be slightly lower than those of their powder counterparts, which was attributed to lower crystal accessibility on zeolite layers. Nevertheless, the set of experimental data demonstrated that the obtained materials are fully conversant with the target application. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901683y Exemplaires
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Titre : Superhydrophobic surface fabricated from fatty acid-modified precipitated calcium carbonate Type de document : texte imprimé Auteurs : Zeshan Hu, Auteur ; Yulin Deng, Auteur Année de publication : 2010 Article en page(s) : pp. 5625–5630 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Superhydrophobic surface Precipitated calcium carbonate Fatty acid Résumé : A very low-cost and simple method for fabricating a superhydrophobic surface with commercially available precipitated calcium carbonate (PCC) and fatty acid is reported in this research article. PCC particles were chemically modified from hydrophilic to hydrophobic in water with fatty acid. The thin film formed by these hydrophobic PCCs shows superhydrophobic and self-cleaning properties. The contact angle hysteresis of modified PCC film was investigated. A sliding angle of 1.75° could be obtained with oleic acid-modified PCC film at an oleic acid concentration of 2.52 wt %. Comparing with oleic acid, the PCC film modified by stearic acid has a higher sliding angle (∼10°). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901944n
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5625–5630[article] Superhydrophobic surface fabricated from fatty acid-modified precipitated calcium carbonate [texte imprimé] / Zeshan Hu, Auteur ; Yulin Deng, Auteur . - 2010 . - pp. 5625–5630.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5625–5630
Mots-clés : Superhydrophobic surface Precipitated calcium carbonate Fatty acid Résumé : A very low-cost and simple method for fabricating a superhydrophobic surface with commercially available precipitated calcium carbonate (PCC) and fatty acid is reported in this research article. PCC particles were chemically modified from hydrophilic to hydrophobic in water with fatty acid. The thin film formed by these hydrophobic PCCs shows superhydrophobic and self-cleaning properties. The contact angle hysteresis of modified PCC film was investigated. A sliding angle of 1.75° could be obtained with oleic acid-modified PCC film at an oleic acid concentration of 2.52 wt %. Comparing with oleic acid, the PCC film modified by stearic acid has a higher sliding angle (∼10°). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901944n Exemplaires
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Titre : Numerical simulation of ethanol−water−NaCl droplet evaporation Type de document : texte imprimé Auteurs : Xingmao Jiang, Auteur ; Timothy L. Ward, Auteur ; Frank van Swol, Auteur Année de publication : 2010 Article en page(s) : pp. 5631–5643 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Droplet evaporation Water Ethanol droplets Résumé : A quantitative description of droplet evaporation is important to aerosol research for nanofabrication, spray drying, fuel combustion, pollution control, and respiratory medical treatments. Evaporation is a moving-boundary problem with coupled mass and heat transport. An explicit finite-difference methodology and computer code has been developed for simulation of an evolving droplet, property data for size, and profiles for various compositions and temperature. The code accurately predicts the evaporation of pure water and pure ethanol droplets. To understand aerosol-assisted evaporation-induced self-assembly and the formation mechanism for single-crystal NaCl core/hexagonally ordered mesoporous silica shell particles, evaporation of ethanol−water−NaCl droplets in N2 has been investigated by numerical simulation. The extended universal quasichemical (UNIQUAC) model with a Debye−Hückel term is used to describe the vapor−liquid phase equilibrium. For 1−2-μm-radius droplets with a number density of 107∼108/cm3, it takes only tens of milliseconds to reach phase equilibrium after adiabatic or isothermal evaporation at 25 °C in the drying zone. The droplets entering a heating zone can be simply treated like a single-stage flash evaporation at 25 °C. For a 1-μm-radius droplet, after 0.18 ms of evaporation at 100 °C in N2, the NaCl saturation ratio reaches levels as high as 1.3, first at the droplet center, where the initial NaCl nucleation and crystallization happens as a result of relatively quick evaporation and a steep gradient in the concentration of ethanol, an antisolvent for NaCl. NaCl crystallization “consumes” NaCl molecules near the droplet center and quenches the formation of new stable NaCl nuclei, favoring the formation of only one single-crystal NaCl core per droplet. The code provides guidance for the custom engineering of aerosol nanoparticle architectures. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie902042z
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5631–5643[article] Numerical simulation of ethanol−water−NaCl droplet evaporation [texte imprimé] / Xingmao Jiang, Auteur ; Timothy L. Ward, Auteur ; Frank van Swol, Auteur . - 2010 . - pp. 5631–5643.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5631–5643
Mots-clés : Droplet evaporation Water Ethanol droplets Résumé : A quantitative description of droplet evaporation is important to aerosol research for nanofabrication, spray drying, fuel combustion, pollution control, and respiratory medical treatments. Evaporation is a moving-boundary problem with coupled mass and heat transport. An explicit finite-difference methodology and computer code has been developed for simulation of an evolving droplet, property data for size, and profiles for various compositions and temperature. The code accurately predicts the evaporation of pure water and pure ethanol droplets. To understand aerosol-assisted evaporation-induced self-assembly and the formation mechanism for single-crystal NaCl core/hexagonally ordered mesoporous silica shell particles, evaporation of ethanol−water−NaCl droplets in N2 has been investigated by numerical simulation. The extended universal quasichemical (UNIQUAC) model with a Debye−Hückel term is used to describe the vapor−liquid phase equilibrium. For 1−2-μm-radius droplets with a number density of 107∼108/cm3, it takes only tens of milliseconds to reach phase equilibrium after adiabatic or isothermal evaporation at 25 °C in the drying zone. The droplets entering a heating zone can be simply treated like a single-stage flash evaporation at 25 °C. For a 1-μm-radius droplet, after 0.18 ms of evaporation at 100 °C in N2, the NaCl saturation ratio reaches levels as high as 1.3, first at the droplet center, where the initial NaCl nucleation and crystallization happens as a result of relatively quick evaporation and a steep gradient in the concentration of ethanol, an antisolvent for NaCl. NaCl crystallization “consumes” NaCl molecules near the droplet center and quenches the formation of new stable NaCl nuclei, favoring the formation of only one single-crystal NaCl core per droplet. The code provides guidance for the custom engineering of aerosol nanoparticle architectures. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie902042z Exemplaires
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Titre : Engineering of a wet-end additives program relative to process parameters and to the physical and optical properties of filled paper Type de document : texte imprimé Auteurs : Gyeong-Yun Kim, Auteur ; Martin A. Hubbe, Auteur ; Chul-Hwan Kim, Auteur Année de publication : 2010 Article en page(s) : pp. 5644–5653 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Paper handsheets Wet-end additives Résumé : In the manufacture of a paper product, the application of wet-end additives and the adjustments of various conditions can have major effects on the physical and optical properties of the final paper. In this study, we prepared paper handsheets and investigated the effects of many process variables, including the type and amounts of cationic polyacrylamide and colloidal silica, in addition to temperature, duration of mixing, hydrodynamic shear, pH, and variations in electrical conductivity due to salt addition. The most important effects were attributable to variations in the amount, ionic charge, and molecular weight of cationic polyacrylamide, as well as the type and amount of colloidal silica. Many of the observed effects could be explained in terms of fiber flocculation, and the adverse effect of flocculation on the uniformity of the paper, a factor that significantly affected the physical properties. An understanding of the relationships between chemical variables, hydrodynamic shear, and other system variables can be helpful in selecting optimal operating conditions to meet process requirements as well as physical properties of the resulting paper. A statistical analysis was carried out, using normalized coordinates, to show which of the independent variables had significant effects on the response variables. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100434u
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5644–5653[article] Engineering of a wet-end additives program relative to process parameters and to the physical and optical properties of filled paper [texte imprimé] / Gyeong-Yun Kim, Auteur ; Martin A. Hubbe, Auteur ; Chul-Hwan Kim, Auteur . - 2010 . - pp. 5644–5653.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5644–5653
Mots-clés : Paper handsheets Wet-end additives Résumé : In the manufacture of a paper product, the application of wet-end additives and the adjustments of various conditions can have major effects on the physical and optical properties of the final paper. In this study, we prepared paper handsheets and investigated the effects of many process variables, including the type and amounts of cationic polyacrylamide and colloidal silica, in addition to temperature, duration of mixing, hydrodynamic shear, pH, and variations in electrical conductivity due to salt addition. The most important effects were attributable to variations in the amount, ionic charge, and molecular weight of cationic polyacrylamide, as well as the type and amount of colloidal silica. Many of the observed effects could be explained in terms of fiber flocculation, and the adverse effect of flocculation on the uniformity of the paper, a factor that significantly affected the physical properties. An understanding of the relationships between chemical variables, hydrodynamic shear, and other system variables can be helpful in selecting optimal operating conditions to meet process requirements as well as physical properties of the resulting paper. A statistical analysis was carried out, using normalized coordinates, to show which of the independent variables had significant effects on the response variables. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100434u Exemplaires
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Titre : Transient diffusion within spherical particles : numerical resolution of the Maxwell−Stefan formulation Type de document : texte imprimé Auteurs : Erminia Leonardi, Auteur ; Celestino Angeli, Auteur Année de publication : 2010 Article en page(s) : pp. 5654–5660 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Maxwell− Stefan equations Physical systems Mass-transfer Résumé : The generalized Maxwell−Stefan equations describe the mass-transfer process in a multicomponent mixture in different physical systems. This approach to the mass-transfer phenomenon has been largely used in particular for the simulation of the multicomponent diffusion in microporous systems. Our group has recently proposed (Leonardi, E.; Angeli, C. J. Phys. Chem. B 2010, 114, 151) a general numerical procedure for the resolution of the Maxwell−Stefan equations in the transient regime for one-dimensional systems. This procedure has been applied for the study of bulk diffusion, the uptake process on a microporous material, and permeation across a microporous membrane. In this paper this approach is extended to the case of diffusion within a sphere, which can be reduced to a one-dimensional problem in the presence of isotropy. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1004724
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5654–5660[article] Transient diffusion within spherical particles : numerical resolution of the Maxwell−Stefan formulation [texte imprimé] / Erminia Leonardi, Auteur ; Celestino Angeli, Auteur . - 2010 . - pp. 5654–5660.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5654–5660
Mots-clés : Maxwell− Stefan equations Physical systems Mass-transfer Résumé : The generalized Maxwell−Stefan equations describe the mass-transfer process in a multicomponent mixture in different physical systems. This approach to the mass-transfer phenomenon has been largely used in particular for the simulation of the multicomponent diffusion in microporous systems. Our group has recently proposed (Leonardi, E.; Angeli, C. J. Phys. Chem. B 2010, 114, 151) a general numerical procedure for the resolution of the Maxwell−Stefan equations in the transient regime for one-dimensional systems. This procedure has been applied for the study of bulk diffusion, the uptake process on a microporous material, and permeation across a microporous membrane. In this paper this approach is extended to the case of diffusion within a sphere, which can be reduced to a one-dimensional problem in the presence of isotropy. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1004724 Exemplaires
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Titre : An operational scheduling model to product distribution through a pipeline network Type de document : texte imprimé Auteurs : Suelen N. Boschetto, Auteur ; Leandro Magatao, Auteur ; William M. Brondani, Auteur Année de publication : 2010 Article en page(s) : pp. 5661–5682 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Pipelines Scheduling Résumé : Pipelines have been proved to be an efficient and economic way to transport oil products. However, the determination of the scheduling of operational activities in pipeline networks is a difficult task, and efficient methods to solve such complex problem are required. In this contribution, a real-world pipeline network is studied, and an optimization model is proposed in order to address the network scheduling activities. A hierarchical approach is proposed on the basis of the integration of a mixed integer linear programming (MILP) model and a set of heuristic modules. This article exploits the MILP model, the main goal of which is to determine the exact time instants that products should be pumped into the pipelines and received in the operational areas. These time instants must satisfy the pipeline network management and operational constraints for a predefined planning period. Such operational constraints include pipeline stoppages, movement of batches through many areas/pipelines, use of preferential routes to avoid contamination losses, on-peak demand hours of pumping, local constraints, reversions of flow direction, and surge tank operations, while satisfying a series of production/consumption requirements. The developed continuous-time model is applied to a large real-world pipeline system, where more than 14 oil derivatives and ethanol are transported and distributed between supply and demand nodes. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900685v
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5661–5682[article] An operational scheduling model to product distribution through a pipeline network [texte imprimé] / Suelen N. Boschetto, Auteur ; Leandro Magatao, Auteur ; William M. Brondani, Auteur . - 2010 . - pp. 5661–5682.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5661–5682
Mots-clés : Pipelines Scheduling Résumé : Pipelines have been proved to be an efficient and economic way to transport oil products. However, the determination of the scheduling of operational activities in pipeline networks is a difficult task, and efficient methods to solve such complex problem are required. In this contribution, a real-world pipeline network is studied, and an optimization model is proposed in order to address the network scheduling activities. A hierarchical approach is proposed on the basis of the integration of a mixed integer linear programming (MILP) model and a set of heuristic modules. This article exploits the MILP model, the main goal of which is to determine the exact time instants that products should be pumped into the pipelines and received in the operational areas. These time instants must satisfy the pipeline network management and operational constraints for a predefined planning period. Such operational constraints include pipeline stoppages, movement of batches through many areas/pipelines, use of preferential routes to avoid contamination losses, on-peak demand hours of pumping, local constraints, reversions of flow direction, and surge tank operations, while satisfying a series of production/consumption requirements. The developed continuous-time model is applied to a large real-world pipeline system, where more than 14 oil derivatives and ethanol are transported and distributed between supply and demand nodes. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900685v Exemplaires
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Titre : Operation condition optimization of p-Xylene oxidation reaction process based on a fuzzy adaptive immune algorithm Type de document : texte imprimé Auteurs : He Hong, Auteur ; Du Wenli, Auteur ; Qian Feng, Auteur Année de publication : 2010 Article en page(s) : pp. 5683–5693 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : p-xylene to terephthalic acid Oxidation Fuzzy adaptive immune algorithm Résumé : The oxidation of p-xylene to terephthalic acid (TA) is a significant chemical process of purified TA production. Variation of operation conditions of the reaction directly affects the quality of TA. In this paper a fuzzy adaptive immune algorithm (FAIA) was proposed to realize the operation condition optimization of the p-xylene oxidation reaction. In FAIA, a chaotic hypermutation was developed to strengthen the searching ability of the algorithm, and a new immune network regulatory strategy was devised to maintain population adversity. Furthermore, two fuzzy logic modules were constructed to adjust parameters, further increasing the adaptability of the algorithm. The data of function optimization show that FAIA can quickly converge to the global optimum and overcome premature problems. Optimization results of process variable values of the p-xylene oxidation reaction indicate that the application of FAIA in an oxidation reaction process can greatly save the time of operation condition selection and reduce production cost. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900969c
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5683–5693[article] Operation condition optimization of p-Xylene oxidation reaction process based on a fuzzy adaptive immune algorithm [texte imprimé] / He Hong, Auteur ; Du Wenli, Auteur ; Qian Feng, Auteur . - 2010 . - pp. 5683–5693.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5683–5693
Mots-clés : p-xylene to terephthalic acid Oxidation Fuzzy adaptive immune algorithm Résumé : The oxidation of p-xylene to terephthalic acid (TA) is a significant chemical process of purified TA production. Variation of operation conditions of the reaction directly affects the quality of TA. In this paper a fuzzy adaptive immune algorithm (FAIA) was proposed to realize the operation condition optimization of the p-xylene oxidation reaction. In FAIA, a chaotic hypermutation was developed to strengthen the searching ability of the algorithm, and a new immune network regulatory strategy was devised to maintain population adversity. Furthermore, two fuzzy logic modules were constructed to adjust parameters, further increasing the adaptability of the algorithm. The data of function optimization show that FAIA can quickly converge to the global optimum and overcome premature problems. Optimization results of process variable values of the p-xylene oxidation reaction indicate that the application of FAIA in an oxidation reaction process can greatly save the time of operation condition selection and reduce production cost. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900969c Exemplaires
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Titre : Optimization of a chemical vapor deposition process using sequential experimental design Type de document : texte imprimé Auteurs : Paul J. Wissmann, Auteur ; Martha A. Grover, Auteur Année de publication : 2010 Article en page(s) : pp. 5694–5701 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Chemical vapor deposition Sequential experimental design Résumé : The exact mechanisms occurring during chemical vapor deposition are often not well understood or quantified, and CVD is therefore difficult to optimize efficiently. In this article, we implement a process optimization method based on sequential experimental design. This method simultaneously employs both mechanistic and empirical models, using confidence intervals to predict the region of potential optima. New experiments are constrained to this region, so that model predictions will be improved near the process optimum. After six initial experiments and two sequential experiments, a process temperature of 760 °C is computed, to achieve a desired film roughness of 7 ± 1.65 nm. The experimental data are obtained using a chemical vapor deposition system. The yttrium precursor material is deposited onto a 1 in. silicon wafer in a vacuum chamber. The samples are then analyzed using an atomic force microscope to determine the roughness of the samples. On the basis of these data, we create models that are purely empirical, and also models that are motivated by a more mechanistic understanding of the process. The rationale is that, rather than concentrating our experimental design on creating either empirical or mechanistic models, both types of models should be considered when optimizing a process. Furthermore, by developing both model types simultaneously, mechanistic understanding of the process can also be improved. Models are developed which predict the thin film roughness from the surface temperature and molar flow rate of the precursor. Five empirical models are considered, as well as two additional models which relate nucleation density to final film roughness using mechanistic modeling. The temperature is found to be most important for controlling the thin film roughness. An empirical model with two fitted parameters and a linear temperature dependence predicted performance best, while a hybrid model using nucleation density and two fitted parameters was second best. The confidence interval for the best model was reduced by 20% using our experimental methodology, using only two sequential experiments. The experiments indicate that the hybrid model does capture some of the trends of the experimental data but needs a stronger dependence on temperature to have more statistical significance. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901055e
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5694–5701[article] Optimization of a chemical vapor deposition process using sequential experimental design [texte imprimé] / Paul J. Wissmann, Auteur ; Martha A. Grover, Auteur . - 2010 . - pp. 5694–5701.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5694–5701
Mots-clés : Chemical vapor deposition Sequential experimental design Résumé : The exact mechanisms occurring during chemical vapor deposition are often not well understood or quantified, and CVD is therefore difficult to optimize efficiently. In this article, we implement a process optimization method based on sequential experimental design. This method simultaneously employs both mechanistic and empirical models, using confidence intervals to predict the region of potential optima. New experiments are constrained to this region, so that model predictions will be improved near the process optimum. After six initial experiments and two sequential experiments, a process temperature of 760 °C is computed, to achieve a desired film roughness of 7 ± 1.65 nm. The experimental data are obtained using a chemical vapor deposition system. The yttrium precursor material is deposited onto a 1 in. silicon wafer in a vacuum chamber. The samples are then analyzed using an atomic force microscope to determine the roughness of the samples. On the basis of these data, we create models that are purely empirical, and also models that are motivated by a more mechanistic understanding of the process. The rationale is that, rather than concentrating our experimental design on creating either empirical or mechanistic models, both types of models should be considered when optimizing a process. Furthermore, by developing both model types simultaneously, mechanistic understanding of the process can also be improved. Models are developed which predict the thin film roughness from the surface temperature and molar flow rate of the precursor. Five empirical models are considered, as well as two additional models which relate nucleation density to final film roughness using mechanistic modeling. The temperature is found to be most important for controlling the thin film roughness. An empirical model with two fitted parameters and a linear temperature dependence predicted performance best, while a hybrid model using nucleation density and two fitted parameters was second best. The confidence interval for the best model was reduced by 20% using our experimental methodology, using only two sequential experiments. The experiments indicate that the hybrid model does capture some of the trends of the experimental data but needs a stronger dependence on temperature to have more statistical significance. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901055e Exemplaires
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Titre : Handling uncertainty in model-based optimal experimental design Type de document : texte imprimé Auteurs : Tilman Barz, Auteur ; Harvey Arellano-Garcia, Auteur ; Günter Wozny, Auteur Année de publication : 2010 Article en page(s) : pp. 5702–5713 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Uncertainties Protein ion-exchange equilibrium parameters Résumé : In contrast to the majority of published works in the field of model-based optimal experimental design which focused on numerical studies so as to demonstrate the validity of the OED approach or the development of new criteria or numerical approaches, this work is mainly concerned with the experimental application and practical insights gained from the adaption of an optimal design framework. The presented work is discussed based on the determination of protein ion-exchange equilibrium parameters. For this purpose, special attention is paid to the explicit modeling of all laboratory steps so as to prepare, implement, and analyze experiments in order to have a realistic definition of the numeric design problem and to formally include experimental restrictions and sources of uncertainties in the problem formulation. Moreover, whereas the effect of erroneous assumptions in the initially assumed parameter values have been covered by various authors, in this work, uncertainties are considered in a more general way including those which arise during an imprecise implementation of optimal planned experiments. To compensate for uncertainty influences, a feed-back based approach to optimal design is adopted based on the combination of the parallel and sequential design approaches. Uncertainty identification is done by solution of an augmented parameter estimation problem, where deviations in the experimental design are detected and estimated together with the parameter values. It has been shown that uncertainty influences vanish along with the iterative refinement of the experiment design variables and estimated parameter values. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901611b
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5702–5713[article] Handling uncertainty in model-based optimal experimental design [texte imprimé] / Tilman Barz, Auteur ; Harvey Arellano-Garcia, Auteur ; Günter Wozny, Auteur . - 2010 . - pp. 5702–5713.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5702–5713
Mots-clés : Uncertainties Protein ion-exchange equilibrium parameters Résumé : In contrast to the majority of published works in the field of model-based optimal experimental design which focused on numerical studies so as to demonstrate the validity of the OED approach or the development of new criteria or numerical approaches, this work is mainly concerned with the experimental application and practical insights gained from the adaption of an optimal design framework. The presented work is discussed based on the determination of protein ion-exchange equilibrium parameters. For this purpose, special attention is paid to the explicit modeling of all laboratory steps so as to prepare, implement, and analyze experiments in order to have a realistic definition of the numeric design problem and to formally include experimental restrictions and sources of uncertainties in the problem formulation. Moreover, whereas the effect of erroneous assumptions in the initially assumed parameter values have been covered by various authors, in this work, uncertainties are considered in a more general way including those which arise during an imprecise implementation of optimal planned experiments. To compensate for uncertainty influences, a feed-back based approach to optimal design is adopted based on the combination of the parallel and sequential design approaches. Uncertainty identification is done by solution of an augmented parameter estimation problem, where deviations in the experimental design are detected and estimated together with the parameter values. It has been shown that uncertainty influences vanish along with the iterative refinement of the experiment design variables and estimated parameter values. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901611b Exemplaires
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Titre : Sulfur recovery units : adaptive simulation and model validation on an industrial plant Type de document : texte imprimé Auteurs : Stefano Signor, Auteur ; Flavio Manenti, Auteur ; Maria Grazia Grottoli, Auteur Année de publication : 2010 Article en page(s) : pp. 5714–5724 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Sulfur recovery units Adaptive simulation parameters Italy Résumé : The paper is aimed at discussing and fixing issues in providing a generalized approach to the simulation of sulfur recovery units (SRUs). The main goal is to get a simulation that is at the same time (i) reasonably detailed and robust to properly characterize SRUs and (ii) so generalized to provide a tool that is not only specific for the case in study. To achieve point (i), standard libraries belonging to commercial process simulators are coupled to specific heuristic relations coming from the industrial experience for modeling the thermal furnace and the catalytic Claus converters; this allows us to infer with a certain reliability those measures that are often missing or unavailable online in these processes. To achieve point (ii), a series of adaptive parameters are filled in the process simulation by making it more flexible and yet preserving all model details. The most recent techniques and numerical methods, to tune the adaptive simulation parameters, are implemented in Visual C++ and interfaced to PRO/II (by SimSci-Esscor) to obtain a robust parameter estimation solved by means of the BzzMath library. At last, the detailed and tuned adaptive simulation is validated along a period of 2 months on a large-scale SRU (TECHNIP-KTI SpA technology) operating in Italy. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901749t
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5714–5724[article] Sulfur recovery units : adaptive simulation and model validation on an industrial plant [texte imprimé] / Stefano Signor, Auteur ; Flavio Manenti, Auteur ; Maria Grazia Grottoli, Auteur . - 2010 . - pp. 5714–5724.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5714–5724
Mots-clés : Sulfur recovery units Adaptive simulation parameters Italy Résumé : The paper is aimed at discussing and fixing issues in providing a generalized approach to the simulation of sulfur recovery units (SRUs). The main goal is to get a simulation that is at the same time (i) reasonably detailed and robust to properly characterize SRUs and (ii) so generalized to provide a tool that is not only specific for the case in study. To achieve point (i), standard libraries belonging to commercial process simulators are coupled to specific heuristic relations coming from the industrial experience for modeling the thermal furnace and the catalytic Claus converters; this allows us to infer with a certain reliability those measures that are often missing or unavailable online in these processes. To achieve point (ii), a series of adaptive parameters are filled in the process simulation by making it more flexible and yet preserving all model details. The most recent techniques and numerical methods, to tune the adaptive simulation parameters, are implemented in Visual C++ and interfaced to PRO/II (by SimSci-Esscor) to obtain a robust parameter estimation solved by means of the BzzMath library. At last, the detailed and tuned adaptive simulation is validated along a period of 2 months on a large-scale SRU (TECHNIP-KTI SpA technology) operating in Italy. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901749t Exemplaires
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Titre : Feasible input manipulation for a nonisothermal direct methanol fuel cell system Type de document : texte imprimé Auteurs : W. Wu, Auteur ; Y.-T. Lin, Auteur Année de publication : 2010 Article en page(s) : pp. 5725–5733 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Direct methanol fuel cell Methanol crossover Water Résumé : Through a semiexperimental dynamic modeling of a direct methanol fuel cell (DMFC) system, transient behaviors on describing cell temperature, methanol crossover, water crossover, and electric power are presented. By different operating manners, the new input determinations are addressed. To investigate the performance of DMFC systems, the presented fuel and exergetic efficiencies for the specific probe of energy utilization are evaluated. Through both steady-state and unsteady state analyses, the manipulation of cathode pressure and anode inlet flow temperature is a feasible approach for temperature regulation, but methanol crossover is restricted. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901829a
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5725–5733[article] Feasible input manipulation for a nonisothermal direct methanol fuel cell system [texte imprimé] / W. Wu, Auteur ; Y.-T. Lin, Auteur . - 2010 . - pp. 5725–5733.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5725–5733
Mots-clés : Direct methanol fuel cell Methanol crossover Water Résumé : Through a semiexperimental dynamic modeling of a direct methanol fuel cell (DMFC) system, transient behaviors on describing cell temperature, methanol crossover, water crossover, and electric power are presented. By different operating manners, the new input determinations are addressed. To investigate the performance of DMFC systems, the presented fuel and exergetic efficiencies for the specific probe of energy utilization are evaluated. Through both steady-state and unsteady state analyses, the manipulation of cathode pressure and anode inlet flow temperature is a feasible approach for temperature regulation, but methanol crossover is restricted. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901829a Exemplaires
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Titre : Emission source characterization for proactive flare minimization during ethylene plant start-ups Type de document : texte imprimé Auteurs : Chaowei Liu, Auteur ; Qiang Xu, Auteur Année de publication : 2010 Article en page(s) : pp. 5734–5741 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Ethylene plant start-ups Plant-wide dynamic simulations Résumé : Ethylene plant start-ups generate huge amounts of off-spec products for flaring, which cause negative environmental and societal impacts, as well as tremendous raw material and energy losses that could be unitized to generate much more needed products. Thus, cost-effective start-up flare minimization strategies through proactive process design and operation are becoming more important and attractive to the industry. However, fundamental and quantitative studies on start-up flaring emissions are still lacking, such as (i) what kinds of emission species are contained in the flaring sources; (ii) how much of each emission source will be generated during one start-up; and (iii) what is the dynamic emission profile of each emission source with respect to the start-up time? In this paper, rigorous plant-wide dynamic simulations are employed to characterize flaring emission sources under different flare minimization strategies for an ethylene plant start-up. Deep insights of the emission source distribution and simulated dynamic emission profiles are provided. The study enriches the emission inventory with details for industry point sources, which have never been compiled previously. It also provides detailed technical support for both the industry and environmental agencies on evaluating and developing cost-effective flare minimization strategies in the future. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie902002c
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5734–5741[article] Emission source characterization for proactive flare minimization during ethylene plant start-ups [texte imprimé] / Chaowei Liu, Auteur ; Qiang Xu, Auteur . - 2010 . - pp. 5734–5741.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5734–5741
Mots-clés : Ethylene plant start-ups Plant-wide dynamic simulations Résumé : Ethylene plant start-ups generate huge amounts of off-spec products for flaring, which cause negative environmental and societal impacts, as well as tremendous raw material and energy losses that could be unitized to generate much more needed products. Thus, cost-effective start-up flare minimization strategies through proactive process design and operation are becoming more important and attractive to the industry. However, fundamental and quantitative studies on start-up flaring emissions are still lacking, such as (i) what kinds of emission species are contained in the flaring sources; (ii) how much of each emission source will be generated during one start-up; and (iii) what is the dynamic emission profile of each emission source with respect to the start-up time? In this paper, rigorous plant-wide dynamic simulations are employed to characterize flaring emission sources under different flare minimization strategies for an ethylene plant start-up. Deep insights of the emission source distribution and simulated dynamic emission profiles are provided. The study enriches the emission inventory with details for industry point sources, which have never been compiled previously. It also provides detailed technical support for both the industry and environmental agencies on evaluating and developing cost-effective flare minimization strategies in the future. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie902002c Exemplaires
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Titre : Holistic approach for design of minimum water networks using the mixed integer linear programming (MILP) technique Type de document : texte imprimé Auteurs : Zainatul B. Handani, Auteur ; Sharifah R. Wan Alwi, Auteur ; Haslenda Hashim, Auteur Année de publication : 2010 Article en page(s) : pp. 5742–5751 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Mixed integer linear programming Fresh water Wastewater Résumé : Minimum fresh water consumption and wastewater generation in a facility can be achieved when all options for water minimization including source elimination, reduction, reuse/recycle, outsourcing, and regeneration have been considered. This work presents the development of a new generic mixed integer linear programming (MILP) model to holistically minimize fresh water consumption and wastewater generation for systems involving multiple contaminants where the various options for water minimization are simultaneously considered in order to ultimately generate a minimum water utilization network. The MILP model proposed in this work can be used to simultaneously generate the minimum water targets and design the minimum water network for global water-using operations for buildings and industry. This work also includes cases where fresh water concentrations for all contaminants are assumed to be either zero or non-zero. The approach has been successfully implemented in case studies involving an urban building (Sultan Ismail Mosque, UTM) and a manufacturing plant (a chlor-alkali plant). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1000357
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5742–5751[article] Holistic approach for design of minimum water networks using the mixed integer linear programming (MILP) technique [texte imprimé] / Zainatul B. Handani, Auteur ; Sharifah R. Wan Alwi, Auteur ; Haslenda Hashim, Auteur . - 2010 . - pp. 5742–5751.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5742–5751
Mots-clés : Mixed integer linear programming Fresh water Wastewater Résumé : Minimum fresh water consumption and wastewater generation in a facility can be achieved when all options for water minimization including source elimination, reduction, reuse/recycle, outsourcing, and regeneration have been considered. This work presents the development of a new generic mixed integer linear programming (MILP) model to holistically minimize fresh water consumption and wastewater generation for systems involving multiple contaminants where the various options for water minimization are simultaneously considered in order to ultimately generate a minimum water utilization network. The MILP model proposed in this work can be used to simultaneously generate the minimum water targets and design the minimum water network for global water-using operations for buildings and industry. This work also includes cases where fresh water concentrations for all contaminants are assumed to be either zero or non-zero. The approach has been successfully implemented in case studies involving an urban building (Sultan Ismail Mosque, UTM) and a manufacturing plant (a chlor-alkali plant). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1000357 Exemplaires
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Titre : Modeling the coke formation in the convection section tubes of a steam cracker Type de document : texte imprimé Auteurs : Sandra C. K. De Schepper, Auteur ; Geraldine J. Heynderickx, Auteur ; Guy B. Marin, Auteur Année de publication : 2010 Article en page(s) : pp. 5752–5764 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Steam cracker Liquid hydrocarbon droplets CFD code Résumé : The presence of liquid hydrocarbon droplets in the convection section of a steam cracker may cause serious fouling problems due to coke formation, especially in high temperature zones. In order to investigate these fouling problems, a model has been developed and implemented in a CFD code to accurately simulate the behavior of a hydrocarbon droplet impinging on a hot surface. The impact energy of the droplet and the hot surface temperature are found to determine the impact behavior. On the basis of the newly developed model, the positions where droplets preferentially collide with the convection section tube walls and liquid material is deposited are determined. Furthermore, a kinetic model describing coke formation out of liquid hydrocarbon droplets in the temperature range of 450−700 K has been developed to calculate the rate of coke formation in each zone of the convection section tube. The calculated coke layer thickness on the most vulnerable tube locations and the industrially available values correspond remarkably well. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100091e
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5752–5764[article] Modeling the coke formation in the convection section tubes of a steam cracker [texte imprimé] / Sandra C. K. De Schepper, Auteur ; Geraldine J. Heynderickx, Auteur ; Guy B. Marin, Auteur . - 2010 . - pp. 5752–5764.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5752–5764
Mots-clés : Steam cracker Liquid hydrocarbon droplets CFD code Résumé : The presence of liquid hydrocarbon droplets in the convection section of a steam cracker may cause serious fouling problems due to coke formation, especially in high temperature zones. In order to investigate these fouling problems, a model has been developed and implemented in a CFD code to accurately simulate the behavior of a hydrocarbon droplet impinging on a hot surface. The impact energy of the droplet and the hot surface temperature are found to determine the impact behavior. On the basis of the newly developed model, the positions where droplets preferentially collide with the convection section tube walls and liquid material is deposited are determined. Furthermore, a kinetic model describing coke formation out of liquid hydrocarbon droplets in the temperature range of 450−700 K has been developed to calculate the rate of coke formation in each zone of the convection section tube. The calculated coke layer thickness on the most vulnerable tube locations and the industrially available values correspond remarkably well. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100091e Exemplaires
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Titre : Cyclic scheduling for ethylene cracking furnace system with consideration of secondary ethane cracking Type de document : texte imprimé Auteurs : Chuanyu Zhao, Auteur ; Chaowei Liu, Auteur ; Qiang Xu, Auteur Année de publication : 2010 Article en page(s) : pp. 5765–5774 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Cracking furnace systems Mixed-integer nonlinear programming Scheduling model Résumé : Cracking furnaces of ethylene plants are capable of processing multiple feeds to produce smaller hydrocarbon molecules, such as ethylene, propylene, and ethane. The best practice for handling the produced ethane is to recycle it as an internal feed and conduct the secondary cracking in a specific furnace. As cracking furnaces have to be periodically shut down for decoking, when multiple furnaces processing different feeds under various product values and manufacturing costs are considered, the operational scheduling for the entire furnace system should be optimized to achieve the best economic performance. In this paper, a new MINLP (mixed-integer nonlinear programming) model has been developed to optimize the operation of cracking furnace systems with the consideration of secondary ethane cracking. This model is more practical than the previous study and can simultaneously identify the allocation of feeds with their quantity, time, and sequence information for each cracking furnace. A case study has demonstrated the efficacy of the developed scheduling model. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1001235
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5765–5774[article] Cyclic scheduling for ethylene cracking furnace system with consideration of secondary ethane cracking [texte imprimé] / Chuanyu Zhao, Auteur ; Chaowei Liu, Auteur ; Qiang Xu, Auteur . - 2010 . - pp. 5765–5774.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5765–5774
Mots-clés : Cracking furnace systems Mixed-integer nonlinear programming Scheduling model Résumé : Cracking furnaces of ethylene plants are capable of processing multiple feeds to produce smaller hydrocarbon molecules, such as ethylene, propylene, and ethane. The best practice for handling the produced ethane is to recycle it as an internal feed and conduct the secondary cracking in a specific furnace. As cracking furnaces have to be periodically shut down for decoking, when multiple furnaces processing different feeds under various product values and manufacturing costs are considered, the operational scheduling for the entire furnace system should be optimized to achieve the best economic performance. In this paper, a new MINLP (mixed-integer nonlinear programming) model has been developed to optimize the operation of cracking furnace systems with the consideration of secondary ethane cracking. This model is more practical than the previous study and can simultaneously identify the allocation of feeds with their quantity, time, and sequence information for each cracking furnace. A case study has demonstrated the efficacy of the developed scheduling model. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1001235 Exemplaires
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Titre : Optimization of a fed-batch simultaneous saccharification and cofermentation process from lignocellulose to ethanol Type de document : texte imprimé Auteurs : Ming-Liang Chen, Auteur ; Feng-Sheng Wang, Auteur Année de publication : 2010 Article en page(s) : pp. 5775–5785 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : imultaneous saccharification Fed-batch process Ethanol Résumé : This paper presents the design of optimal control policies for a fed-batch process of simultaneous saccharification and cofermentation to produce ethanol from lignocellulose using enzymes and a recombinant yeast. The goal of the optimal design herein is to find the optimal feed rate, temperature, feed lignocellulosic concentration, and fermentation time that maximizes the ethanol production rate under the constraints of operational restrictions. We applied an Arrhenius relationship to each rate constant to express the temperature effect on the kinetic model for both saccharification and fermentation. Good bioreactor performance not only is defined as the maximum production rate yielded but also considers follow-up separation specifications as the constraints for the optimization problem. Additional restrictions were also considered in the optimization problem to cope with operating costs and environmental impact. Both crisp and fuzzy optimization methods are applied to solve the problem. The fuzzy optimization approach more flexibly obtains a compromised design compared with the crisp optimization method. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1001982
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5775–5785[article] Optimization of a fed-batch simultaneous saccharification and cofermentation process from lignocellulose to ethanol [texte imprimé] / Ming-Liang Chen, Auteur ; Feng-Sheng Wang, Auteur . - 2010 . - pp. 5775–5785.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5775–5785
Mots-clés : imultaneous saccharification Fed-batch process Ethanol Résumé : This paper presents the design of optimal control policies for a fed-batch process of simultaneous saccharification and cofermentation to produce ethanol from lignocellulose using enzymes and a recombinant yeast. The goal of the optimal design herein is to find the optimal feed rate, temperature, feed lignocellulosic concentration, and fermentation time that maximizes the ethanol production rate under the constraints of operational restrictions. We applied an Arrhenius relationship to each rate constant to express the temperature effect on the kinetic model for both saccharification and fermentation. Good bioreactor performance not only is defined as the maximum production rate yielded but also considers follow-up separation specifications as the constraints for the optimization problem. Additional restrictions were also considered in the optimization problem to cope with operating costs and environmental impact. Both crisp and fuzzy optimization methods are applied to solve the problem. The fuzzy optimization approach more flexibly obtains a compromised design compared with the crisp optimization method. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1001982 Exemplaires
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Titre : Multiobjective optimization for design and operation of the chilling train system in ethylene plants Type de document : texte imprimé Auteurs : Jian Zhang, Auteur ; Yanqin Wen, Auteur ; Qiang Xu, Auteur Année de publication : 2010 Article en page(s) : pp. 5786–5799 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Chilling train system Mixed-integer nonlinear programming Résumé : The chilling train is a very important section for ethylene plants, as its design and operation significantly influence energy consumption and product loss rates. In this paper, a systematic methodology for the optimal design and operation of a chilling train system has been presented. A multiobjective mixed-integer nonlinear programming (MINLP) model has been developed, which aims at minimizing the ethylene loss rate and the exergy-accounted energy consumption, meanwhile maximizing the hydrogen recovery rate. Also presented are the technologies for obtaining reliable thermodynamic properties based on rigorous simulation and the methods for removing redundant variables for MINLP model simplification. On the basis of the methodology, the optimal design and operating conditions of a chilling train system can be simultaneously achieved. A real case study has demonstrated the efficacy of the developed methodology. The results show that the optimized chilling train system has better economic performance than the current system. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100455g
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5786–5799[article] Multiobjective optimization for design and operation of the chilling train system in ethylene plants [texte imprimé] / Jian Zhang, Auteur ; Yanqin Wen, Auteur ; Qiang Xu, Auteur . - 2010 . - pp. 5786–5799.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5786–5799
Mots-clés : Chilling train system Mixed-integer nonlinear programming Résumé : The chilling train is a very important section for ethylene plants, as its design and operation significantly influence energy consumption and product loss rates. In this paper, a systematic methodology for the optimal design and operation of a chilling train system has been presented. A multiobjective mixed-integer nonlinear programming (MINLP) model has been developed, which aims at minimizing the ethylene loss rate and the exergy-accounted energy consumption, meanwhile maximizing the hydrogen recovery rate. Also presented are the technologies for obtaining reliable thermodynamic properties based on rigorous simulation and the methods for removing redundant variables for MINLP model simplification. On the basis of the methodology, the optimal design and operating conditions of a chilling train system can be simultaneously achieved. A real case study has demonstrated the efficacy of the developed methodology. The results show that the optimized chilling train system has better economic performance than the current system. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100455g Exemplaires
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Titre : Measurements of liquid−liquid equilibria for a methanol + glycerol + methyl oleate system and prediction using group contribution statistical associating fluid theory Type de document : texte imprimé Auteurs : A. Barreau, Auteur ; I. Brunella, Auteur ; Jean-Charles de Hemptinne, Auteur Année de publication : 2010 Article en page(s) : pp. 5800–5807 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Ternary system Vapor− liquid− liquid dataFatty acid methyl ester Glycerol Methanol ternary Résumé : A good understanding and prediction of the phase equilibrium of the fatty acid methyl ester (FAME) + glycerol + methanol ternary system is needed to design and optimize the separation unit of the biodiesel production process. In this work, new experimental vapor−liquid−liquid data on the ternary system have been measured at temperatures between 333.15 and 473.15 K. In addition, new data have been gathered on the methanol + glycerol [vapor−liquid equilibrium (VLE)] and methanol + methyl oleate (VLE and liquid−liquid equilibrium) binary systems. A group contribution method combined with a statistical associating fluid theory equation of state (GC-PPC-SAFT) proposed earlier by our group (Tamouza, S., Passarello, J.-P., Tobaly, P., and de Hemptinne, J.-C.Group contribution method with SAFT EOS applied to vapor liquid equilibria of various hydrocarbons series. Fluid Phase Equilib. 2004, 222−223, 67−76) and recently extended to predict VLE of heavy esters and their mixtures (Nguyen Huynh, D., Falaix, A., Passarello, J.-P., Tobaly, P., and de Hemptinne, J.-C.Predicting VLE of heavy esters and their mixtures using GC-SAFT. Fluid Phase Equilib. 2008, 264, 184−200) is here applied to model vapor liquid−liquid equilibria of methanol + glycerol + methyl oleate. The SAFT parameters for the glycerol pure component have been regressed using two association schemes (4C and 3X2B). The dispersive binary interaction parameters kij have been regressed on the binary systems. The group contribution scheme was used for predicting the ester properties. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901379x
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5800–5807[article] Measurements of liquid−liquid equilibria for a methanol + glycerol + methyl oleate system and prediction using group contribution statistical associating fluid theory [texte imprimé] / A. Barreau, Auteur ; I. Brunella, Auteur ; Jean-Charles de Hemptinne, Auteur . - 2010 . - pp. 5800–5807.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5800–5807
Mots-clés : Ternary system Vapor− liquid− liquid dataFatty acid methyl ester Glycerol Methanol ternary Résumé : A good understanding and prediction of the phase equilibrium of the fatty acid methyl ester (FAME) + glycerol + methanol ternary system is needed to design and optimize the separation unit of the biodiesel production process. In this work, new experimental vapor−liquid−liquid data on the ternary system have been measured at temperatures between 333.15 and 473.15 K. In addition, new data have been gathered on the methanol + glycerol [vapor−liquid equilibrium (VLE)] and methanol + methyl oleate (VLE and liquid−liquid equilibrium) binary systems. A group contribution method combined with a statistical associating fluid theory equation of state (GC-PPC-SAFT) proposed earlier by our group (Tamouza, S., Passarello, J.-P., Tobaly, P., and de Hemptinne, J.-C.Group contribution method with SAFT EOS applied to vapor liquid equilibria of various hydrocarbons series. Fluid Phase Equilib. 2004, 222−223, 67−76) and recently extended to predict VLE of heavy esters and their mixtures (Nguyen Huynh, D., Falaix, A., Passarello, J.-P., Tobaly, P., and de Hemptinne, J.-C.Predicting VLE of heavy esters and their mixtures using GC-SAFT. Fluid Phase Equilib. 2008, 264, 184−200) is here applied to model vapor liquid−liquid equilibria of methanol + glycerol + methyl oleate. The SAFT parameters for the glycerol pure component have been regressed using two association schemes (4C and 3X2B). The dispersive binary interaction parameters kij have been regressed on the binary systems. The group contribution scheme was used for predicting the ester properties. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901379x Exemplaires
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Titre : Stability and performance study of water-in-oil-in-water emulsion : extraction of aromatic amines Type de document : texte imprimé Auteurs : Jaydeep M. Barad, Auteur Année de publication : 2010 Article en page(s) : pp. 5808–5815 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Emulsion liquid membranes Internal acid phase Surfactant concentration Stirrer speed Résumé : One of the major obstacles to the application of emulsion liquid membranes to industrial separations is the stability of emulsion globules. Stability of emulsion is affected by two phenomena—globule rupture and osmotic swell. Interfacial shear between the continuous and membrane phase causes the liquid membrane to thin and, in some cases, rupture, thereby affecting separation. Destabilization phenomena affecting the homogeneity of dispersions are emulsion globule migration (creaming, sedimentation) and size variation or aggregation (coalescence, flocculation). In the present study, the stability of an emulsion liquid membrane is studied by varying different parameters, for example, internal acid phase and surfactant concentration and stirrer speed for emulsification. Dispersion destabilization of the emulsion is detected by Turbiscan. Properties such as interfacial tension, drop size distribution, photomicrographs, and zeta potential are also analyzed to evaluate emulsion stability. A stable emulsion is used for the removal of aromatic amines from aqueous solutions. An advancing reaction front model considering competitive transport of aromatic amines has been proposed to simulate data. The simulated curves are found to be in good agreement with the experimental data. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901698u
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5808–5815[article] Stability and performance study of water-in-oil-in-water emulsion : extraction of aromatic amines [texte imprimé] / Jaydeep M. Barad, Auteur . - 2010 . - pp. 5808–5815.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5808–5815
Mots-clés : Emulsion liquid membranes Internal acid phase Surfactant concentration Stirrer speed Résumé : One of the major obstacles to the application of emulsion liquid membranes to industrial separations is the stability of emulsion globules. Stability of emulsion is affected by two phenomena—globule rupture and osmotic swell. Interfacial shear between the continuous and membrane phase causes the liquid membrane to thin and, in some cases, rupture, thereby affecting separation. Destabilization phenomena affecting the homogeneity of dispersions are emulsion globule migration (creaming, sedimentation) and size variation or aggregation (coalescence, flocculation). In the present study, the stability of an emulsion liquid membrane is studied by varying different parameters, for example, internal acid phase and surfactant concentration and stirrer speed for emulsification. Dispersion destabilization of the emulsion is detected by Turbiscan. Properties such as interfacial tension, drop size distribution, photomicrographs, and zeta potential are also analyzed to evaluate emulsion stability. A stable emulsion is used for the removal of aromatic amines from aqueous solutions. An advancing reaction front model considering competitive transport of aromatic amines has been proposed to simulate data. The simulated curves are found to be in good agreement with the experimental data. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901698u Exemplaires
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Titre : Sorption of CO, CH4, and N2 in alkali metal ion exchanged zeolite-X : grand canonical Monte Carlo simulation and volumetric measurements Type de document : texte imprimé Auteurs : Renjith S. Pillai, Auteur ; Govind Sethia, Auteur ; Raksh V. Jasra, Auteur Année de publication : 2010 Article en page(s) : pp. 5816–5825 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : CO sorption CH4 sorptionN2Alkali metal ions Monte Carlo simulation Résumé : Sorption of CO, CH4, and N2 in zeolite-X exchanged with different alkali metal ions was studied by volumetric measurements and Grand Canonical Monte Carlo simulation. CO and CH4 sorption is observed to show higher sorption capacity than N2 in all cation exchanged zeolite samples. The adsorption capacity of CO in alkali metal exchanged zeolites is observed to decrease on moving from LiX to CsX, whereas for the methane adsorption capacity varies in reverse order. The isosteric heat of sorption data show stronger interactions of CO and N2 molecules with alkali metal ion exchanged zeolites. The isosteric heat of CH4 show nearly same value (21−24 kJ/mol) for all alkali metal ion exchanged zeolites. Simulation of the CO and N2 sorption in alkali metal zeolite -X clearly shows that the adsorbed CO and N2 molecules are located in proximity to the extra-framework cations in the super cage. Simulated data of adsorption isotherms and heats of adsorption of CO, N2, and CH4 in alkali metal ion exchanged zeolite-X agree reasonably well with the experimental results. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901713m
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5816–5825[article] Sorption of CO, CH4, and N2 in alkali metal ion exchanged zeolite-X : grand canonical Monte Carlo simulation and volumetric measurements [texte imprimé] / Renjith S. Pillai, Auteur ; Govind Sethia, Auteur ; Raksh V. Jasra, Auteur . - 2010 . - pp. 5816–5825.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5816–5825
Mots-clés : CO sorption CH4 sorptionN2Alkali metal ions Monte Carlo simulation Résumé : Sorption of CO, CH4, and N2 in zeolite-X exchanged with different alkali metal ions was studied by volumetric measurements and Grand Canonical Monte Carlo simulation. CO and CH4 sorption is observed to show higher sorption capacity than N2 in all cation exchanged zeolite samples. The adsorption capacity of CO in alkali metal exchanged zeolites is observed to decrease on moving from LiX to CsX, whereas for the methane adsorption capacity varies in reverse order. The isosteric heat of sorption data show stronger interactions of CO and N2 molecules with alkali metal ion exchanged zeolites. The isosteric heat of CH4 show nearly same value (21−24 kJ/mol) for all alkali metal ion exchanged zeolites. Simulation of the CO and N2 sorption in alkali metal zeolite -X clearly shows that the adsorbed CO and N2 molecules are located in proximity to the extra-framework cations in the super cage. Simulated data of adsorption isotherms and heats of adsorption of CO, N2, and CH4 in alkali metal ion exchanged zeolite-X agree reasonably well with the experimental results. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901713m Exemplaires
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Titre : Potential desorbents for propane/propylene separation by gas phase simulated moving bed : a molecular simulation study Type de document : texte imprimé Auteurs : Miguel A. Granato, Auteur ; Thijs J.H. Vlugt, Auteur ; Alirio E. Rodrigues, Auteur Année de publication : 2010 Article en page(s) : pp. 5826–5833 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Separation propane/propylene Simulated moving bed process Equilibrium adsorption isotherms n-butane Neopentane on zeolite 13X Binary mixtures Résumé : This paper is focused on using molecular simulation as a tool to guide the choice of desorbent for the separation propane/propylene by simulated moving bed (SMB) processes. Equilibrium adsorption isotherms of n-butane and neopentane on zeolite 13X and adsorption equilibria of binary mixtures of each one of these adsorbates with propane and with propylene were obtained by molecular simulation, in a predictive screening of an adequate desorbent for the separation of propane/propylene by the SMB technology. Comparisons of experimental isotherms with grand canonical Monte Carlo simulations in zeolite 13X showed that the results of n-butane are in excellent agreement with reported simulations and experimental data. The carbon−cation interactions for the quaternary carbon atom of neopentane were established and validated through determination of adsorption properties of binary mixtures of neopentane with propane and with propylene. The lack of experimental data of neopentane adsorption motivated the present study, providing the opportunity to predict the single adsorption isotherms over a temperature range from 273 to 423 K and pressures up to 150 kPa. From the simulated isotherms of neopentane in 13X zeolite, the isosteric heat of adsorption of 39.19 kJ/mol was calculated by using the Clausius−Clapeyron equation, in close agreement with the published value of 41.7 kJ/mol. Additionally, the simulation results of the binary mixtures with propane and with propylene showed that neopentane and propane have similar affinities to the adsorbent, which indicates a less favorable desorption effect for neopentane, compared with that of n-butane. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901732s
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5826–5833[article] Potential desorbents for propane/propylene separation by gas phase simulated moving bed : a molecular simulation study [texte imprimé] / Miguel A. Granato, Auteur ; Thijs J.H. Vlugt, Auteur ; Alirio E. Rodrigues, Auteur . - 2010 . - pp. 5826–5833.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5826–5833
Mots-clés : Separation propane/propylene Simulated moving bed process Equilibrium adsorption isotherms n-butane Neopentane on zeolite 13X Binary mixtures Résumé : This paper is focused on using molecular simulation as a tool to guide the choice of desorbent for the separation propane/propylene by simulated moving bed (SMB) processes. Equilibrium adsorption isotherms of n-butane and neopentane on zeolite 13X and adsorption equilibria of binary mixtures of each one of these adsorbates with propane and with propylene were obtained by molecular simulation, in a predictive screening of an adequate desorbent for the separation of propane/propylene by the SMB technology. Comparisons of experimental isotherms with grand canonical Monte Carlo simulations in zeolite 13X showed that the results of n-butane are in excellent agreement with reported simulations and experimental data. The carbon−cation interactions for the quaternary carbon atom of neopentane were established and validated through determination of adsorption properties of binary mixtures of neopentane with propane and with propylene. The lack of experimental data of neopentane adsorption motivated the present study, providing the opportunity to predict the single adsorption isotherms over a temperature range from 273 to 423 K and pressures up to 150 kPa. From the simulated isotherms of neopentane in 13X zeolite, the isosteric heat of adsorption of 39.19 kJ/mol was calculated by using the Clausius−Clapeyron equation, in close agreement with the published value of 41.7 kJ/mol. Additionally, the simulation results of the binary mixtures with propane and with propylene showed that neopentane and propane have similar affinities to the adsorbent, which indicates a less favorable desorption effect for neopentane, compared with that of n-butane. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901732s Exemplaires
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Titre : Effect of feed spacer mesh length ratio on unsteady hydrodynamics in 2D spiral wound membrane (SWM) channel Type de document : texte imprimé Auteurs : K. K. Lau, Auteur ; M. Z. Abu Bakar, Auteur ; A. L. Ahmad, Auteur Année de publication : 2010 Article en page(s) : pp. 5834–5845 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Ladder-type spacer mesh length ratio Spiral wound membranes Computational fluid dynamics approach Résumé : The present work involves the simulation and optimization of the ladder-type spacer mesh length (ML) ratio in spiral wound membranes (SWMs), using a two-dimensional (2D) integrated computational fluid dynamics (CFD) approach. The permeation properties, incorporated with a transient unsteady hydrodynamics modeling approach, were used to analyze and optimize the ML value for SWM feed spacers. The influence of unsteady hydrodynamics on the development of the concentration polarization in the membrane channel was also investigated. The optimum ML ratio was determined to be 3, because of its ability to generate a high intensity of unsteady hydrodynamics with the lowest effective concentration polarization factor and the results were further validated using velocity vector plots, wall shear stress analysis, and the localized concentration polarization factor. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9017989
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5834–5845[article] Effect of feed spacer mesh length ratio on unsteady hydrodynamics in 2D spiral wound membrane (SWM) channel [texte imprimé] / K. K. Lau, Auteur ; M. Z. Abu Bakar, Auteur ; A. L. Ahmad, Auteur . - 2010 . - pp. 5834–5845.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5834–5845
Mots-clés : Ladder-type spacer mesh length ratio Spiral wound membranes Computational fluid dynamics approach Résumé : The present work involves the simulation and optimization of the ladder-type spacer mesh length (ML) ratio in spiral wound membranes (SWMs), using a two-dimensional (2D) integrated computational fluid dynamics (CFD) approach. The permeation properties, incorporated with a transient unsteady hydrodynamics modeling approach, were used to analyze and optimize the ML value for SWM feed spacers. The influence of unsteady hydrodynamics on the development of the concentration polarization in the membrane channel was also investigated. The optimum ML ratio was determined to be 3, because of its ability to generate a high intensity of unsteady hydrodynamics with the lowest effective concentration polarization factor and the results were further validated using velocity vector plots, wall shear stress analysis, and the localized concentration polarization factor. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9017989 Exemplaires
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Titre : Regular solution theory for low pressure carbon dioxide solubility in room temperature ionic liquids : ionic liquid solubility parameter from activation energy of viscosity Type de document : texte imprimé Auteurs : Surya S. Moganty, Auteur ; Ruth E. Baltus, Auteur Année de publication : 2010 Article en page(s) : pp. 5846–5853 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Carbon dioxide solubility Ionic liquids Transient thin liquid film technique Résumé : The low pressure solubility of carbon dioxide in eight commercially available room temperature ionic liquids was measured at 10, 25, and 40 °C using a transient thin liquid film technique. In this paper, carbon dioxide solubility is reported as the Henry’s law constant for each system. Experimental results were interpreted using regular solution theory where Eyring’s reaction rate theory was successfully applied to estimate the solubility parameter of each ionic liquid from its activation energy of viscosity. Consistent with the regular solution theory, the carbon dioxide solubility was found to be inversely proportional to the solubility parameter of the ionic liquid, and Henry’s law constants were successfully correlated with the square of the difference between ionic liquid and carbon dioxide solubility parameters. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901837k
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5846–5853[article] Regular solution theory for low pressure carbon dioxide solubility in room temperature ionic liquids : ionic liquid solubility parameter from activation energy of viscosity [texte imprimé] / Surya S. Moganty, Auteur ; Ruth E. Baltus, Auteur . - 2010 . - pp. 5846–5853.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5846–5853
Mots-clés : Carbon dioxide solubility Ionic liquids Transient thin liquid film technique Résumé : The low pressure solubility of carbon dioxide in eight commercially available room temperature ionic liquids was measured at 10, 25, and 40 °C using a transient thin liquid film technique. In this paper, carbon dioxide solubility is reported as the Henry’s law constant for each system. Experimental results were interpreted using regular solution theory where Eyring’s reaction rate theory was successfully applied to estimate the solubility parameter of each ionic liquid from its activation energy of viscosity. Consistent with the regular solution theory, the carbon dioxide solubility was found to be inversely proportional to the solubility parameter of the ionic liquid, and Henry’s law constants were successfully correlated with the square of the difference between ionic liquid and carbon dioxide solubility parameters. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901837k Exemplaires
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Titre : Precipitation and transformation of the three polymorphs of d-mannitol Type de document : texte imprimé Auteurs : Jeroen Cornel, Auteur ; Piran Kidambi, Auteur ; Mazzotti, Marco, Auteur Année de publication : 2010 Article en page(s) : pp. 5854–5862 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : d-mannitol’s three polymorphs Thermodynamic aspects kinetic Solid-state forms Résumé : In this work, the thermodynamic and kinetic aspects of d-mannitol’s three polymorphs and their transformations are addressed. Scalable and reproducible syntheses of the solid-state forms are presented, and a mathematical model to describe a three-polymorph transformation is discussed in detail. It is shown that, for certain initial solute concentrations, the α polymorph nucleates first and then transforms through the β form to the γ form. Moreover, a supersaturation threshold to nucleate the α form has been observed, and below this threshold value, the γ form nucleates. A theoretical analysis demonstrates that this behavior can be predicted and that this experimental observation is physically sound. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9019616
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5854–5862[article] Precipitation and transformation of the three polymorphs of d-mannitol [texte imprimé] / Jeroen Cornel, Auteur ; Piran Kidambi, Auteur ; Mazzotti, Marco, Auteur . - 2010 . - pp. 5854–5862.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5854–5862
Mots-clés : d-mannitol’s three polymorphs Thermodynamic aspects kinetic Solid-state forms Résumé : In this work, the thermodynamic and kinetic aspects of d-mannitol’s three polymorphs and their transformations are addressed. Scalable and reproducible syntheses of the solid-state forms are presented, and a mathematical model to describe a three-polymorph transformation is discussed in detail. It is shown that, for certain initial solute concentrations, the α polymorph nucleates first and then transforms through the β form to the γ form. Moreover, a supersaturation threshold to nucleate the α form has been observed, and below this threshold value, the γ form nucleates. A theoretical analysis demonstrates that this behavior can be predicted and that this experimental observation is physically sound. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9019616 Exemplaires
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Titre : Extraction of tetra-oxo anions into a hydrophobic, ionic liquid-based solvent without concomitant ion exchange Type de document : texte imprimé Auteurs : Dominique C. Stepinski, Auteur ; George F. Vandegrift, Auteur ; Ilya A. Shkrob, Auteur Année de publication : 2010 Article en page(s) : pp. 5863–5868 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Ionic liquids Tetra-oxo anions Résumé : Hydrophobic ionic liquids (IL) have the potential to simplify certain separations by serving as both an extraction solvent and an electrolyte for subsequent electrochemical reductions. While IL-based solvents are known to be efficient media for metal ion extraction, separations employing these solvents are frequently complicated by the loss of constituent IL ions to the aqueous phase, resulting in deteriorating performance. In this study, we have examined the extraction of pertechnetate and related tetra-oxo anions from aqueous solutions into IL-based solvents incorporating tetraalkylphosphonium bis[(trifluoromethyl)sulfonyl]imide and a crown ether. In contrast to various previously studied IL-based cation extraction systems, facile anion extraction without significant transfer of the IL ions to the aqueous phase has been observed. In addition, the solvents exhibit high distribution ratios (100−500 for pertechnetate), significant electrical conductivity (>100 μS/cm), and a wide (∼4 V) electrochemical window. The results suggest that these solvents may provide the basis for improved approaches to the extraction and recovery of a variety of anions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1000345
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5863–5868[article] Extraction of tetra-oxo anions into a hydrophobic, ionic liquid-based solvent without concomitant ion exchange [texte imprimé] / Dominique C. Stepinski, Auteur ; George F. Vandegrift, Auteur ; Ilya A. Shkrob, Auteur . - 2010 . - pp. 5863–5868.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5863–5868
Mots-clés : Ionic liquids Tetra-oxo anions Résumé : Hydrophobic ionic liquids (IL) have the potential to simplify certain separations by serving as both an extraction solvent and an electrolyte for subsequent electrochemical reductions. While IL-based solvents are known to be efficient media for metal ion extraction, separations employing these solvents are frequently complicated by the loss of constituent IL ions to the aqueous phase, resulting in deteriorating performance. In this study, we have examined the extraction of pertechnetate and related tetra-oxo anions from aqueous solutions into IL-based solvents incorporating tetraalkylphosphonium bis[(trifluoromethyl)sulfonyl]imide and a crown ether. In contrast to various previously studied IL-based cation extraction systems, facile anion extraction without significant transfer of the IL ions to the aqueous phase has been observed. In addition, the solvents exhibit high distribution ratios (100−500 for pertechnetate), significant electrical conductivity (>100 μS/cm), and a wide (∼4 V) electrochemical window. The results suggest that these solvents may provide the basis for improved approaches to the extraction and recovery of a variety of anions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1000345 Exemplaires
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Titre : Highly water-soluble magnetic nanoparticles as novel draw solutes in forward osmosis for water reuse Type de document : texte imprimé Auteurs : Ming Ming Ling, Auteur ; Kai Yu Wang, Auteur ; Tai-Shung Chung, Auteur Année de publication : 2010 Article en page(s) : pp. 5869–5876 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Magnetic nanoparticles Highly water-soluble magnetic Résumé : Highly hydrophilic magnetic nanoparticles have been molecularly designed. For the first time, the application of highly water-soluble magnetic nanoparticles as novel draw solutes in forward osmosis (FO) was systematically investigated. Magnetic nanoparticles functionalized by various groups were synthesized to explore the correlation between the surface chemistry of magnetic nanoparticles and the achieved osmolality. We verified that magnetic nanoparticles capped with polyacrylic acid can yield the highest driving force and subsequently highest water flux among others. The used magnetic nanoparticles can be captured by the magnetic field and recycled back into the stream as draw solutes in the FO process. In addition, magnetic nanoparticles of different diameters were also synthesized to study the effect of particles size on FO performance. We demonstrate that the engineering of surface hydrophilicity and magnetic nanoparticle size is crucial in the application of nanoparticles as draw solutes in FO. It is believed that magnetic nanoparticles will soon be extensively used in this area. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100438x
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5869–5876[article] Highly water-soluble magnetic nanoparticles as novel draw solutes in forward osmosis for water reuse [texte imprimé] / Ming Ming Ling, Auteur ; Kai Yu Wang, Auteur ; Tai-Shung Chung, Auteur . - 2010 . - pp. 5869–5876.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5869–5876
Mots-clés : Magnetic nanoparticles Highly water-soluble magnetic Résumé : Highly hydrophilic magnetic nanoparticles have been molecularly designed. For the first time, the application of highly water-soluble magnetic nanoparticles as novel draw solutes in forward osmosis (FO) was systematically investigated. Magnetic nanoparticles functionalized by various groups were synthesized to explore the correlation between the surface chemistry of magnetic nanoparticles and the achieved osmolality. We verified that magnetic nanoparticles capped with polyacrylic acid can yield the highest driving force and subsequently highest water flux among others. The used magnetic nanoparticles can be captured by the magnetic field and recycled back into the stream as draw solutes in the FO process. In addition, magnetic nanoparticles of different diameters were also synthesized to study the effect of particles size on FO performance. We demonstrate that the engineering of surface hydrophilicity and magnetic nanoparticle size is crucial in the application of nanoparticles as draw solutes in FO. It is believed that magnetic nanoparticles will soon be extensively used in this area. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100438x Exemplaires
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Titre : Stagnation point offset of two opposed jets Type de document : texte imprimé Auteurs : Zhi-gang Sun, Auteur ; Wei-feng Li, Auteur ; Hai Feng Liu, Auteur Année de publication : 2010 Article en page(s) : pp. 5877–5883 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Axial velocity Stagnation point offset Impinging streamsSmoke wire visualization Hot-wire anemometry techniques Résumé : The axial velocity and the stagnation point offset of impinging streams from two opposed nozzles have been theoretically studied and experimentally measured by smoke wire visualization and hot-wire anemometry (HWA) techniques. The results show that, for small nozzle separation (L/D 12), the equations based on the free jet theory can be used to predict the stagnation point offset for two nozzles of the same and different sizes. The illustrated effects of the exit momentum ratio and the nozzle separation on the stagnation point offset are useful for defining the optimum conditions for many industrial applications of the opposed jets. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901056x
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5877–5883[article] Stagnation point offset of two opposed jets [texte imprimé] / Zhi-gang Sun, Auteur ; Wei-feng Li, Auteur ; Hai Feng Liu, Auteur . - 2010 . - pp. 5877–5883.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5877–5883
Mots-clés : Axial velocity Stagnation point offset Impinging streamsSmoke wire visualization Hot-wire anemometry techniques Résumé : The axial velocity and the stagnation point offset of impinging streams from two opposed nozzles have been theoretically studied and experimentally measured by smoke wire visualization and hot-wire anemometry (HWA) techniques. The results show that, for small nozzle separation (L/D 12), the equations based on the free jet theory can be used to predict the stagnation point offset for two nozzles of the same and different sizes. The illustrated effects of the exit momentum ratio and the nozzle separation on the stagnation point offset are useful for defining the optimum conditions for many industrial applications of the opposed jets. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901056x Exemplaires
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Titre : Effects of monoethylene glycol on carbon dioxide partitioning in gas/monoethylene glycol/water/salt mixed systems Type de document : texte imprimé Auteurs : Amy T. Kan, Auteur ; Haiping Lu, Auteur ; Mason B. Tomson, Auteur Année de publication : 2010 Article en page(s) : pp. 5884–5890 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Carbon dioxide partitioning Gas/liquid equilibrium NaCl− H2O− monoethylene glycol (MEG) mixed solvent Résumé : This paper extended the experimental results of carbon dioxide partitioning in gas/liquid equilibrium with a NaCl−H2O−monoethylene glycol (MEG) mixed solvent. The experiments were conducted systematically at 3−70 °C, 0−6.0 m NaCl, and 0−99 wt % MEG concentrations. CO2 partitioning to the NaCl−H2O−MEG solution is complicated due to nonideal behavior in the solvent. A self-consistent activity model is proposed to describe the effect of monoethylene glycol (MEG) on CO2 partitioning in gas/MEG/water/salt solutions using pure H2O as the reference state. Pitzer theory was used to calculate the effect of salt, and a semiempirical equation was applied to correlate the effects of MEG at different temperatures and ionic strengths. The equation is applicable to CO2 partitioning at 0−6 mol of NaCl and 0−97% MEG mixed solution at 0−90 °C. This model can be incorporated with Pitzer type activity coefficient models to predict the solubility of carbon dioxide in the presence of MEG and salt solutions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901274v
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5884–5890[article] Effects of monoethylene glycol on carbon dioxide partitioning in gas/monoethylene glycol/water/salt mixed systems [texte imprimé] / Amy T. Kan, Auteur ; Haiping Lu, Auteur ; Mason B. Tomson, Auteur . - 2010 . - pp. 5884–5890.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5884–5890
Mots-clés : Carbon dioxide partitioning Gas/liquid equilibrium NaCl− H2O− monoethylene glycol (MEG) mixed solvent Résumé : This paper extended the experimental results of carbon dioxide partitioning in gas/liquid equilibrium with a NaCl−H2O−monoethylene glycol (MEG) mixed solvent. The experiments were conducted systematically at 3−70 °C, 0−6.0 m NaCl, and 0−99 wt % MEG concentrations. CO2 partitioning to the NaCl−H2O−MEG solution is complicated due to nonideal behavior in the solvent. A self-consistent activity model is proposed to describe the effect of monoethylene glycol (MEG) on CO2 partitioning in gas/MEG/water/salt solutions using pure H2O as the reference state. Pitzer theory was used to calculate the effect of salt, and a semiempirical equation was applied to correlate the effects of MEG at different temperatures and ionic strengths. The equation is applicable to CO2 partitioning at 0−6 mol of NaCl and 0−97% MEG mixed solution at 0−90 °C. This model can be incorporated with Pitzer type activity coefficient models to predict the solubility of carbon dioxide in the presence of MEG and salt solutions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901274v Exemplaires
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Titre : Magnetic resonance studies of fluidization regimes Type de document : texte imprimé Auteurs : D. J. Holland, Auteur ; C. R. Müller, Auteur ; J. S. Dennis, Auteur Année de publication : 2010 Article en page(s) : pp. 5891–5899 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Magnetic resonance Gas-fluidized bed Résumé : Measurements of the voidage and velocity distributions in a gas-fluidized bed operating in the bubbling, turbulent, and core−annular fluidization regimes were acquired using magnetic resonance imaging (MR). The bed studied was contained in a column 50 mm in diameter and was fluidized with air. The particles were silica−alumina catalyst support loaded with water doped with gadolinium (diameter 63 μm, density of the water loaded particles 1530 kg m−3). Both time-averaged and ultrafast measurements are presented and provide the first noninvasive measurements of the velocities of particles and local voidage in a fluidized bed in each of the flow regimes. Measurements of the pressure fluctuations were also recorded as a function of the superficial velocity of the fluidizing gas to compare with the MR measurements. Ultrafast measurements of the voidage were used to examine the void structures present in the different flow regimes and to provide a means of studying the dynamics. A novel MR technique was used to measure the velocities of the particles in a diametral region of 15 mm × 15 mm square cross-section through the center of the bed every 7.7 ms. These measurements confirmed that the highest particle velocities in the bubbling fluidization regime occurred in the wakes of bubbles. The distribution of particle velocities in a bubbling bed is highly skewed; however, it approaches a Gaussian distribution and appears to scale with the superficial gas velocity in the turbulent fluidization regime. Finally, a simple model to infer the slip velocity in core−annular fluidization indicates that the particles in the center of the column group together in clusters with a diameter of between 4 and 8 particles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901450q
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5891–5899[article] Magnetic resonance studies of fluidization regimes [texte imprimé] / D. J. Holland, Auteur ; C. R. Müller, Auteur ; J. S. Dennis, Auteur . - 2010 . - pp. 5891–5899.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5891–5899
Mots-clés : Magnetic resonance Gas-fluidized bed Résumé : Measurements of the voidage and velocity distributions in a gas-fluidized bed operating in the bubbling, turbulent, and core−annular fluidization regimes were acquired using magnetic resonance imaging (MR). The bed studied was contained in a column 50 mm in diameter and was fluidized with air. The particles were silica−alumina catalyst support loaded with water doped with gadolinium (diameter 63 μm, density of the water loaded particles 1530 kg m−3). Both time-averaged and ultrafast measurements are presented and provide the first noninvasive measurements of the velocities of particles and local voidage in a fluidized bed in each of the flow regimes. Measurements of the pressure fluctuations were also recorded as a function of the superficial velocity of the fluidizing gas to compare with the MR measurements. Ultrafast measurements of the voidage were used to examine the void structures present in the different flow regimes and to provide a means of studying the dynamics. A novel MR technique was used to measure the velocities of the particles in a diametral region of 15 mm × 15 mm square cross-section through the center of the bed every 7.7 ms. These measurements confirmed that the highest particle velocities in the bubbling fluidization regime occurred in the wakes of bubbles. The distribution of particle velocities in a bubbling bed is highly skewed; however, it approaches a Gaussian distribution and appears to scale with the superficial gas velocity in the turbulent fluidization regime. Finally, a simple model to infer the slip velocity in core−annular fluidization indicates that the particles in the center of the column group together in clusters with a diameter of between 4 and 8 particles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901450q Exemplaires
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Titre : Numerical simulation of pneumatic dryers using computational fluid dynamics Type de document : texte imprimé Auteurs : Tarek J. Jamaleddine, Auteur ; Madhumita B. Ray, Auteur Année de publication : 2010 Article en page(s) : pp. 5900–5910 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Hydrodynamic mechanism Drying mechanisms Gas-solid flow Fluid dynamics Résumé : The hydrodynamic and drying mechanisms of a dilute-phase, gas-solid flow have been predicted in a laboratory and a large-scale pneumatic dryer. A computational fluid dynamics (CFD) method based on the two-fluid multiphase flow model has been adopted. A control-volume based technique implemented in the FLUENT CFD package was applied along with the kinetic theory of granular flow (KTGF) to simulate the flow pattern and heat and mass transfer processes for wet PVC and sand particles by hot air. The mass-weighted averages of theoretical predictions for temperature and moisture content agree well with the experimental data for similar models. User-defined subroutines were added to extend FLUENT capability to account for mixture properties and to simulate the drying rate for surface moisture evaporation and moisture diffusion inside the particulate phase. The present model can be extended to simulate the drying of various temperature sensitive materials. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901816s
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5900–5910[article] Numerical simulation of pneumatic dryers using computational fluid dynamics [texte imprimé] / Tarek J. Jamaleddine, Auteur ; Madhumita B. Ray, Auteur . - 2010 . - pp. 5900–5910.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5900–5910
Mots-clés : Hydrodynamic mechanism Drying mechanisms Gas-solid flow Fluid dynamics Résumé : The hydrodynamic and drying mechanisms of a dilute-phase, gas-solid flow have been predicted in a laboratory and a large-scale pneumatic dryer. A computational fluid dynamics (CFD) method based on the two-fluid multiphase flow model has been adopted. A control-volume based technique implemented in the FLUENT CFD package was applied along with the kinetic theory of granular flow (KTGF) to simulate the flow pattern and heat and mass transfer processes for wet PVC and sand particles by hot air. The mass-weighted averages of theoretical predictions for temperature and moisture content agree well with the experimental data for similar models. User-defined subroutines were added to extend FLUENT capability to account for mixture properties and to simulate the drying rate for surface moisture evaporation and moisture diffusion inside the particulate phase. The present model can be extended to simulate the drying of various temperature sensitive materials. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901816s Exemplaires
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Titre : Comparison of high resolution schemes for solving population balances Type de document : texte imprimé Auteurs : Ala Eldin Bouaswaig, Auteur ; Sebastian Engell, Auteur Année de publication : 2010 Article en page(s) : pp. 5911–5924 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Population balance equation High resolution discretization methods Résumé : The physical properties of particulate products such as crystals and polymers are strongly dependent on their size distribution which is usually modeled by a population balance equation (PBE). The PBE is an integro-partial differential equation and due to its hyperbolic nature, steep fronts are encountered in the solution profile. When solved numerically, the discretization of the PBE has to be performed with care to avoid numerical diffusion, and dispersion and appropriate numerical methods have to be chosen for that purpose. In this work, an extensive investigation of the performance of several high resolution discretization methods when applied to the PBE is performed with the objective to determine the most promising among them in terms of accuracy and computation time. The comparison is performed on standard benchmark problems and on a practical PBE that arises from modeling the growth of a seed of particles in emulsion polymerization. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9020057
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5911–5924[article] Comparison of high resolution schemes for solving population balances [texte imprimé] / Ala Eldin Bouaswaig, Auteur ; Sebastian Engell, Auteur . - 2010 . - pp. 5911–5924.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5911–5924
Mots-clés : Population balance equation High resolution discretization methods Résumé : The physical properties of particulate products such as crystals and polymers are strongly dependent on their size distribution which is usually modeled by a population balance equation (PBE). The PBE is an integro-partial differential equation and due to its hyperbolic nature, steep fronts are encountered in the solution profile. When solved numerically, the discretization of the PBE has to be performed with care to avoid numerical diffusion, and dispersion and appropriate numerical methods have to be chosen for that purpose. In this work, an extensive investigation of the performance of several high resolution discretization methods when applied to the PBE is performed with the objective to determine the most promising among them in terms of accuracy and computation time. The comparison is performed on standard benchmark problems and on a practical PBE that arises from modeling the growth of a seed of particles in emulsion polymerization. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9020057 Exemplaires
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Titre : Effect of experimental conditions on measuring autoignition temperatures of liquid chemicals Type de document : texte imprimé Auteurs : Chan-Cheng Chen, Auteur ; Yen-Cheng Hsieh, Auteur Année de publication : 2010 Article en page(s) : pp. 5925–5932 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Autoignition temperature Résumé : The principal application of autoignition temperature (AIT) is to define the maximum acceptable surface temperature in a particular area, usually for electrical classification purpose. However, although AITs are indispensable information for safely handling flammable liquids, the reported AITs of flammable liquids in different data compilations are very much diverse. Sometimes, the difference in separate data compilations might up to more than 300 K. This article aims to explore the quantitative effects of flask material, ambient temperature, and ambient humidity on the accuracy for measuring AIT via the method of ASTM E659. To effectively analyze these factors simultaneously, the L9(34) orthogonal arrays are used to allocate experiments, and experiments are then carefully conducted in a temperature- and humidity-controlled laboratory chamber. It is found that ambient humidity does not affect the measured AIT of ethanol, but both flask material and ambient temperature are significant factors in measuring AIT of ethanol. An experiment of measuring AIT of ethanol conducted with a flask material of quartz is found to result in a higher AIT value than the one conducted with a flask material of borosilicate by 20 °C. A quadratic relation between the measured AIT of ethanol (y) and the ambient temperature (x) is found, and it is also found that a quadratic polynomial of y = 3.450 × 10−2 x2 − 1.454x + 3.711 × 102 could properly fit this relation with R2 = 0.9939. According to aforementioned quadratic relation, the ambient temperature at which the lowest AIT of ethanol appears is about 21 °C. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9020649
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5925–5932[article] Effect of experimental conditions on measuring autoignition temperatures of liquid chemicals [texte imprimé] / Chan-Cheng Chen, Auteur ; Yen-Cheng Hsieh, Auteur . - 2010 . - pp. 5925–5932.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5925–5932
Mots-clés : Autoignition temperature Résumé : The principal application of autoignition temperature (AIT) is to define the maximum acceptable surface temperature in a particular area, usually for electrical classification purpose. However, although AITs are indispensable information for safely handling flammable liquids, the reported AITs of flammable liquids in different data compilations are very much diverse. Sometimes, the difference in separate data compilations might up to more than 300 K. This article aims to explore the quantitative effects of flask material, ambient temperature, and ambient humidity on the accuracy for measuring AIT via the method of ASTM E659. To effectively analyze these factors simultaneously, the L9(34) orthogonal arrays are used to allocate experiments, and experiments are then carefully conducted in a temperature- and humidity-controlled laboratory chamber. It is found that ambient humidity does not affect the measured AIT of ethanol, but both flask material and ambient temperature are significant factors in measuring AIT of ethanol. An experiment of measuring AIT of ethanol conducted with a flask material of quartz is found to result in a higher AIT value than the one conducted with a flask material of borosilicate by 20 °C. A quadratic relation between the measured AIT of ethanol (y) and the ambient temperature (x) is found, and it is also found that a quadratic polynomial of y = 3.450 × 10−2 x2 − 1.454x + 3.711 × 102 could properly fit this relation with R2 = 0.9939. According to aforementioned quadratic relation, the ambient temperature at which the lowest AIT of ethanol appears is about 21 °C. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9020649 Exemplaires
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Titre : Continuity control of b-oriented MFI zeolite films by microwave synthesis Type de document : texte imprimé Auteurs : Xianming Li, Auteur ; Yushan Yan, Auteur ; Zhengbao Wang, Auteur Année de publication : 2010 Article en page(s) : pp. 5933–5938 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : b-oriented MFI zeolite films Crystallization Résumé : Influences of aging and crystallization conditions on the continuity of b-oriented MFI zeolite films on stainless steel substrates are systematically investigated. A long aging time (e.g., 20 h) at room temperature is needed to obtain a continuous b-oriented MFI zeolite film by the microwave heating at 165 °C. However, the aging time can be shortened from 20 h to 30 min by elevating the aging temperature to 80 °C. Compared with the conventional heating (2 h), continuous b-oriented MFI zeolite films are prepared on stainless steel substrates with a much shorter crystallization time by the microwave heating (35 min). Continuous b-oriented MFI zeolite films can be synthesized by controlling nuclei concentration and crystal size, which are mainly determined by the conditions of the aging and crystallization respectively. On the basis of the results from these experiments, a film continuity−synthesis condition map is obtained and a film formation mechanism is discussed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1000136
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5933–5938[article] Continuity control of b-oriented MFI zeolite films by microwave synthesis [texte imprimé] / Xianming Li, Auteur ; Yushan Yan, Auteur ; Zhengbao Wang, Auteur . - 2010 . - pp. 5933–5938.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5933–5938
Mots-clés : b-oriented MFI zeolite films Crystallization Résumé : Influences of aging and crystallization conditions on the continuity of b-oriented MFI zeolite films on stainless steel substrates are systematically investigated. A long aging time (e.g., 20 h) at room temperature is needed to obtain a continuous b-oriented MFI zeolite film by the microwave heating at 165 °C. However, the aging time can be shortened from 20 h to 30 min by elevating the aging temperature to 80 °C. Compared with the conventional heating (2 h), continuous b-oriented MFI zeolite films are prepared on stainless steel substrates with a much shorter crystallization time by the microwave heating (35 min). Continuous b-oriented MFI zeolite films can be synthesized by controlling nuclei concentration and crystal size, which are mainly determined by the conditions of the aging and crystallization respectively. On the basis of the results from these experiments, a film continuity−synthesis condition map is obtained and a film formation mechanism is discussed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1000136 Exemplaires
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Titre : Energy estimation on CRN process of fly ash as a slow-release nitrogen fertilizer Type de document : texte imprimé Auteurs : Qi Qiu, Auteur ; V. Hlavacek, Auteur Année de publication : 2010 Article en page(s) : pp. 5939–5944 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Carbothermal reduction and nitridation Nitrogen fertilizer Résumé : Through carbothermal reduction and nitridation (CRN) reaction, nitrogen could be fixed into fly ash up to 28 wt %. Nitrided fly ash has the potential to be a source of slow release nitrogen fertilizer. To further investigate this potential, the energy consumptions were estimated for the nitridation process of fly ash. Reactors such as parallel rotary furnaces were simulated for the heat loss of radiation and convection. Material balance was carried out to determine the dimension of the rotary furnaces. Subsequently, on the basis of the dimension of the rotary furnace, the energy balance was performed from the reaction engineering aspects of the nitridation reaction of fly ash. Ultimately, the total energy was transformed into per unit nitrogen and compared with the energy consumption of the Haber−Bosch process for ammonia synthesis. The energy balance calculation suggested that there is great potential for nitrided fly ash to be slow release nitrogen fertilizer. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100391y
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5939–5944[article] Energy estimation on CRN process of fly ash as a slow-release nitrogen fertilizer [texte imprimé] / Qi Qiu, Auteur ; V. Hlavacek, Auteur . - 2010 . - pp. 5939–5944.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5939–5944
Mots-clés : Carbothermal reduction and nitridation Nitrogen fertilizer Résumé : Through carbothermal reduction and nitridation (CRN) reaction, nitrogen could be fixed into fly ash up to 28 wt %. Nitrided fly ash has the potential to be a source of slow release nitrogen fertilizer. To further investigate this potential, the energy consumptions were estimated for the nitridation process of fly ash. Reactors such as parallel rotary furnaces were simulated for the heat loss of radiation and convection. Material balance was carried out to determine the dimension of the rotary furnaces. Subsequently, on the basis of the dimension of the rotary furnace, the energy balance was performed from the reaction engineering aspects of the nitridation reaction of fly ash. Ultimately, the total energy was transformed into per unit nitrogen and compared with the energy consumption of the Haber−Bosch process for ammonia synthesis. The energy balance calculation suggested that there is great potential for nitrided fly ash to be slow release nitrogen fertilizer. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100391y Exemplaires
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Titre : Enhanced fiber quality of black spruce (Picea mariana) thermomechanical pulp fiber through selective enzyme application Type de document : texte imprimé Auteurs : Marc J. Sabourin, Auteur Année de publication : 2010 Article en page(s) : pp. 5945–5951 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Black Spruce Thermomechanical pulping Enzyme application Résumé : Two different enzyme applications were applied to black spruce thermomechanical pulping (TMP) in an attempt to selectively enhance the physical properties of the resulting pulp. Past studies have revealed some application difficulties between pulp and enzymes. A new method of enzyme application including fiberizing the wood chips and cooling the fiberized material prior to enzyme application was employed to maximize the fiber surface area available for enzyme reaction and to obtain optimal enzyme reaction temperatures. Fiberized chips are chips that have been destructured in a converging screw chip press followed by low energy refining to produce extremely coarse fiber pulp. TMP pulps obtained from a control sample of whole wood chips, fiberized wood treated with water, and fiberized wood with two different enzyme applications were evaluated for specific refining energy and various physical properties. Scanning electron microscopy (SEM) in conjunction with image analysis techniques was used to determine fiber wall thickness, degree of fiber fibrillation, and percent surface disruption for selected trial pulps. One monocomponent pectinase enzyme evaluated in this work was found to significantly improve various physical properties and increase the specific surface area of the resulting pulp. The multicomponent more aggressive pectinase enzyme evaluated was determined to be less effective at enhancing physical properties than the less aggressive monocomponent enzyme. The new fiberizing application method employed prior to enzyme application was found to reduce the specific refining energy requirements by 7%. When evaluated at a constant freeness, the enzyme treatment in conjunction with the new application method was found to reduce specific refining energy by about 9%. The enzyme application had only minimal impact on energy requirements. The enzyme application did significantly enhance the tensile and tear index of the resulting pulp. Dramatic increases in the amount of fibrillation and fiber surface disruption were also found to result from specific enzyme action upon the fiber. The resulting fiber wall thickness was reduced as a result of the enzyme action as well. Results from this work reveal that selective enzyme application is an effective method for enhancing specific physical properties of TMP pulps. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100681e
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5945–5951[article] Enhanced fiber quality of black spruce (Picea mariana) thermomechanical pulp fiber through selective enzyme application [texte imprimé] / Marc J. Sabourin, Auteur . - 2010 . - pp. 5945–5951.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5945–5951
Mots-clés : Black Spruce Thermomechanical pulping Enzyme application Résumé : Two different enzyme applications were applied to black spruce thermomechanical pulping (TMP) in an attempt to selectively enhance the physical properties of the resulting pulp. Past studies have revealed some application difficulties between pulp and enzymes. A new method of enzyme application including fiberizing the wood chips and cooling the fiberized material prior to enzyme application was employed to maximize the fiber surface area available for enzyme reaction and to obtain optimal enzyme reaction temperatures. Fiberized chips are chips that have been destructured in a converging screw chip press followed by low energy refining to produce extremely coarse fiber pulp. TMP pulps obtained from a control sample of whole wood chips, fiberized wood treated with water, and fiberized wood with two different enzyme applications were evaluated for specific refining energy and various physical properties. Scanning electron microscopy (SEM) in conjunction with image analysis techniques was used to determine fiber wall thickness, degree of fiber fibrillation, and percent surface disruption for selected trial pulps. One monocomponent pectinase enzyme evaluated in this work was found to significantly improve various physical properties and increase the specific surface area of the resulting pulp. The multicomponent more aggressive pectinase enzyme evaluated was determined to be less effective at enhancing physical properties than the less aggressive monocomponent enzyme. The new fiberizing application method employed prior to enzyme application was found to reduce the specific refining energy requirements by 7%. When evaluated at a constant freeness, the enzyme treatment in conjunction with the new application method was found to reduce specific refining energy by about 9%. The enzyme application had only minimal impact on energy requirements. The enzyme application did significantly enhance the tensile and tear index of the resulting pulp. Dramatic increases in the amount of fibrillation and fiber surface disruption were also found to result from specific enzyme action upon the fiber. The resulting fiber wall thickness was reduced as a result of the enzyme action as well. Results from this work reveal that selective enzyme application is an effective method for enhancing specific physical properties of TMP pulps. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100681e Exemplaires
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Titre : Solubility model of solid solute in supercritical fluid solvent based on UNIFAC Type de document : texte imprimé Auteurs : Yueqiang Zhao, Auteur ; Weiwei Liu, Auteur ; Zhengming Wu, Auteur Année de publication : 2010 Article en page(s) : pp. 5952–5957 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : UNIFAC Semitheoretical model based Supercritical fluid (SF) solvent Vapor− liquid equilibrium Résumé : A semitheoretical model based on UNIFAC was proposed to correlate the solubility of solid solute in supercritical fluid (SF) solvent simply and reliably, which does not need critical parameters for solid solutes. The interaction parameters aij between the SF solvents (such as carbon dioxide, ethylene, and ethane) and the functional groups of solutes were regressed, which is compatible with the vapor−liquid equilibrium (VLE) UNIFAC group-interaction parameters. More efforts and experimental data are needed to obtain a sufficiently large number of interaction parameters for extensive applications. The estimated power exponent of reduced density seems identical for the same solid solute in SF cosolvent homologues. This model could predict the solubility of a solid solute in supercritical CO2 with cosolvents successfully. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100656v
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5952–5957[article] Solubility model of solid solute in supercritical fluid solvent based on UNIFAC [texte imprimé] / Yueqiang Zhao, Auteur ; Weiwei Liu, Auteur ; Zhengming Wu, Auteur . - 2010 . - pp. 5952–5957.
Chemical engineering
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5952–5957
Mots-clés : UNIFAC Semitheoretical model based Supercritical fluid (SF) solvent Vapor− liquid equilibrium Résumé : A semitheoretical model based on UNIFAC was proposed to correlate the solubility of solid solute in supercritical fluid (SF) solvent simply and reliably, which does not need critical parameters for solid solutes. The interaction parameters aij between the SF solvents (such as carbon dioxide, ethylene, and ethane) and the functional groups of solutes were regressed, which is compatible with the vapor−liquid equilibrium (VLE) UNIFAC group-interaction parameters. More efforts and experimental data are needed to obtain a sufficiently large number of interaction parameters for extensive applications. The estimated power exponent of reduced density seems identical for the same solid solute in SF cosolvent homologues. This model could predict the solubility of a solid solute in supercritical CO2 with cosolvents successfully. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100656v Exemplaires
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