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Vol. 51 N° 27 - Juillet 2012 [texte imprimé] . - 2012 . - p. 9199-9446 : ill. ; 28 cm. Chemical engineering Langues : Anglais (eng)
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Ajouter le résultat dans votre panierReaction of zein with methylenediphenyl diisocyanate in the melt state / David J. Sessa in Industrial & engineering chemistry research, Vol. 51 N° 27 (Juillet 2012)
Titre : Reaction of zein with methylenediphenyl diisocyanate in the melt state : Thermal, mechanical, and physical properties Type de document : texte imprimé Auteurs : David J. Sessa, Auteur ; Gordon W. Selling, Auteur ; Atanu Biswas, Auteur Année de publication : 2012 Article en page(s) : pp. 9199-9203 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Physical properties Résumé : Com protein (zein) was melt-processed with methylenediphenyl 4,4'-diisocyanate (MDI) using triethylamine (TEA) as a catalyst to facilitate the reaction of the isocyanate groups with the nucleophilic moieties present on zein. The product of the reaction was examined using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) to monitor changes in molecular weight. Techniques used to evaluate property changes after reaction included FTIR, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and evaluation of mechanical properties. Our findings demonstrated that zein reacts with MDI in the melt state generating higher molecular weight compounds that after compression molding have improved physical properties and solvent resistance. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132254
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9199-9203[article] Reaction of zein with methylenediphenyl diisocyanate in the melt state : Thermal, mechanical, and physical properties [texte imprimé] / David J. Sessa, Auteur ; Gordon W. Selling, Auteur ; Atanu Biswas, Auteur . - 2012 . - pp. 9199-9203.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9199-9203
Mots-clés : Physical properties Résumé : Com protein (zein) was melt-processed with methylenediphenyl 4,4'-diisocyanate (MDI) using triethylamine (TEA) as a catalyst to facilitate the reaction of the isocyanate groups with the nucleophilic moieties present on zein. The product of the reaction was examined using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) to monitor changes in molecular weight. Techniques used to evaluate property changes after reaction included FTIR, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and evaluation of mechanical properties. Our findings demonstrated that zein reacts with MDI in the melt state generating higher molecular weight compounds that after compression molding have improved physical properties and solvent resistance. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132254 Exemplaires
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Titre : Improvement of the compatibilization of high - impact polystyrene / magnesium hydroxide composites with partially sulfonated polystyrene as macromolecular compatibilizers Type de document : texte imprimé Auteurs : Zhen Yang, Auteur ; Chengang Zhou, Auteur ; Hu Yang, Auteur Année de publication : 2012 Article en page(s) : pp. 9204-9212 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Composite material Résumé : The partially sulfonated polystyrene (SPS) is a very simple and easily prepared material. In this work, SPS was used for the first time as a macromolecular compatibilizer to improve the compatibilization of high-impact polystyrene (HIPS)/ magnesium hydroxide (MH) composites by self-compatibilization technology. The compatibilization effects of SPS were systematically studied by mechanical performance tests, limiting oxygen index (LOI) measurements, thermal stability analyses, and scanning electron microscopy (SEM) observation. On the basis of these experimental results, SPS was proven efficient to enhance the compatibilization of the HIPS/MH composites due to the coupling effects. The sulfonic groups of SPS could anchor onto the surface of MH particles through interaction with hydroxyl groups of MH. Meanwhile, the long alkyl chains of SPS readily entwisted with HIPS matrix. Besides, the effects of both the sulfonation degree and the content of SPS on the performance of HIPS/MH composites were investigated also. In order to obtain the best overall final performance, both of the aforementioned parameters should be controlled in a suitable range. The optimal condition in this study was 3―4.5 wt % of SPS with sulfonation degree of 24.8―35.5% in the composites. Furthermore, compared with styrene-butadiene-styrene block copolymer (SBS), a commercial compatibilizer widely used in HIPS materials, SPS exhibited better compatibilization effects but lower cost. Therefore, it could be concluded that SPS was applicable as a cost-effective compatibilizer in HIPS/MH composites. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132255
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9204-9212[article] Improvement of the compatibilization of high - impact polystyrene / magnesium hydroxide composites with partially sulfonated polystyrene as macromolecular compatibilizers [texte imprimé] / Zhen Yang, Auteur ; Chengang Zhou, Auteur ; Hu Yang, Auteur . - 2012 . - pp. 9204-9212.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9204-9212
Mots-clés : Composite material Résumé : The partially sulfonated polystyrene (SPS) is a very simple and easily prepared material. In this work, SPS was used for the first time as a macromolecular compatibilizer to improve the compatibilization of high-impact polystyrene (HIPS)/ magnesium hydroxide (MH) composites by self-compatibilization technology. The compatibilization effects of SPS were systematically studied by mechanical performance tests, limiting oxygen index (LOI) measurements, thermal stability analyses, and scanning electron microscopy (SEM) observation. On the basis of these experimental results, SPS was proven efficient to enhance the compatibilization of the HIPS/MH composites due to the coupling effects. The sulfonic groups of SPS could anchor onto the surface of MH particles through interaction with hydroxyl groups of MH. Meanwhile, the long alkyl chains of SPS readily entwisted with HIPS matrix. Besides, the effects of both the sulfonation degree and the content of SPS on the performance of HIPS/MH composites were investigated also. In order to obtain the best overall final performance, both of the aforementioned parameters should be controlled in a suitable range. The optimal condition in this study was 3―4.5 wt % of SPS with sulfonation degree of 24.8―35.5% in the composites. Furthermore, compared with styrene-butadiene-styrene block copolymer (SBS), a commercial compatibilizer widely used in HIPS materials, SPS exhibited better compatibilization effects but lower cost. Therefore, it could be concluded that SPS was applicable as a cost-effective compatibilizer in HIPS/MH composites. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132255 Exemplaires
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Titre : Oil recovery from oil sludge through combined ultrasound and thermochemical cleaning treatment Type de document : texte imprimé Auteurs : Yuqi Jin, Auteur ; Xiaoyuan Zheng, Auteur ; Xiaoliang Chu, Auteur Année de publication : 2012 Article en page(s) : pp. 9213–9217 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Thermochemical cleaning Oil sludge Résumé : Oil sludge from an oil storage tank was treated using a combined ultrasound and thermochemical cleaning method. The effects of cleaning temperature, cleaning time, ultrasound frequency, ultrasound power, and other factors on the oil recovery were investigated. Experiments on the screening and remixing of reagents were conducted and indicated that the best constituents of detergent solution were sodium silicate, sodium dodecyl benzene sulfonate, and fatty alcohol ethoxylates in a ratio of 1:1:1. The optimum conditions of the combined treatment system were also determined. The results showed that, under the optimum conditions, the oil content of oil sludge dropped from 43.13% to 1.01%, 0.53% of solids remained in the separated oil layer, and 99.32% oil recovery could be achieved when the concentration of detergent solution was to 2 g/L. Compared with traditional thermochemical cleaning, the oil recovery was 17.65% higher for the combined treatment system. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301130c
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9213–9217[article] Oil recovery from oil sludge through combined ultrasound and thermochemical cleaning treatment [texte imprimé] / Yuqi Jin, Auteur ; Xiaoyuan Zheng, Auteur ; Xiaoliang Chu, Auteur . - 2012 . - pp. 9213–9217.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9213–9217
Mots-clés : Thermochemical cleaning Oil sludge Résumé : Oil sludge from an oil storage tank was treated using a combined ultrasound and thermochemical cleaning method. The effects of cleaning temperature, cleaning time, ultrasound frequency, ultrasound power, and other factors on the oil recovery were investigated. Experiments on the screening and remixing of reagents were conducted and indicated that the best constituents of detergent solution were sodium silicate, sodium dodecyl benzene sulfonate, and fatty alcohol ethoxylates in a ratio of 1:1:1. The optimum conditions of the combined treatment system were also determined. The results showed that, under the optimum conditions, the oil content of oil sludge dropped from 43.13% to 1.01%, 0.53% of solids remained in the separated oil layer, and 99.32% oil recovery could be achieved when the concentration of detergent solution was to 2 g/L. Compared with traditional thermochemical cleaning, the oil recovery was 17.65% higher for the combined treatment system. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301130c Exemplaires
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Titre : Influence of the particle size of activated carbons on their performance as Fe supports for developing fenton - like catalysts Type de document : texte imprimé Auteurs : Filipa Duarte, Auteur ; F. J. Maldonado-Hodar, Auteur ; Luis M. Madeira, Auteur Année de publication : 2012 Article en page(s) : pp. 9218-9226 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Catalyst Fenton reaction Activated carbon Particle size Résumé : In this work, a commercial activated carbon (AC) impregnated with iron (7 wt % Fe on Fe/AC) was used as catalyst for the removal of the azo dye Orange II (OII) by the heterogeneous Fenton-like process. The influence of the particle size of the AC support on adsorption and catalytic runs was evaluated, using different particle sizes below commercial pellet form (cylinders of ca. 3 × 5 mm). The materials were characterized using several techniques (N2 and CO2 adsorption, XRD, and HRTEM). It was found that the porosity of the extruded AC was liberated by milling, enhancing the adsorption capacity and the adsorption rate. Nevertheless, total discoloration was achieved with the four particle sizes tested, albeit taking ca. 24 h using pellets but only 2 h using the powder, under the tested conditions. The dispersion of iron in the Fenton-like catalysts was also improved with the decrease in AC particle size, which also favored the catalytic activity. However, leaching increased in the same way. This tradeoff between activity and stability points to the intermediate size of 0.80-1.60 mm as the best choice. To analyze the effect of the support particle size on the catalytic performance alone, catalysts were prepared with nearly the same iron dispersion (keeping the loading of iron per unit of surface area constant). The smaller the support, the higher the activity, and thus, the higher the effectiveness factor, because of the competition between the internal diffusion and reaction rates. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132257
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9218-9226[article] Influence of the particle size of activated carbons on their performance as Fe supports for developing fenton - like catalysts [texte imprimé] / Filipa Duarte, Auteur ; F. J. Maldonado-Hodar, Auteur ; Luis M. Madeira, Auteur . - 2012 . - pp. 9218-9226.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9218-9226
Mots-clés : Catalyst Fenton reaction Activated carbon Particle size Résumé : In this work, a commercial activated carbon (AC) impregnated with iron (7 wt % Fe on Fe/AC) was used as catalyst for the removal of the azo dye Orange II (OII) by the heterogeneous Fenton-like process. The influence of the particle size of the AC support on adsorption and catalytic runs was evaluated, using different particle sizes below commercial pellet form (cylinders of ca. 3 × 5 mm). The materials were characterized using several techniques (N2 and CO2 adsorption, XRD, and HRTEM). It was found that the porosity of the extruded AC was liberated by milling, enhancing the adsorption capacity and the adsorption rate. Nevertheless, total discoloration was achieved with the four particle sizes tested, albeit taking ca. 24 h using pellets but only 2 h using the powder, under the tested conditions. The dispersion of iron in the Fenton-like catalysts was also improved with the decrease in AC particle size, which also favored the catalytic activity. However, leaching increased in the same way. This tradeoff between activity and stability points to the intermediate size of 0.80-1.60 mm as the best choice. To analyze the effect of the support particle size on the catalytic performance alone, catalysts were prepared with nearly the same iron dispersion (keeping the loading of iron per unit of surface area constant). The smaller the support, the higher the activity, and thus, the higher the effectiveness factor, because of the competition between the internal diffusion and reaction rates. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132257 Exemplaires
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Titre : Evolution of reactive concentration during borohydride - reduced electroless nickel – boron plating and design of a replenishment procedure Type de document : texte imprimé Auteurs : Véronique Vitry, Auteur ; Abdoul-Fatah Kanta, Auteur ; Fabienne Delaunois, Auteur Année de publication : 2012 Article en page(s) : pp. 9227-9234 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Design Résumé : Electroless nickel―boron samples with 5 wt % boron were synthesized on mild steel with a bath based on sodium borohydride. Evolution of chemistry in the bath was followed during plating. Most reactive was consumed during the first half hour of the process. However, reducing agent and stabilizer concentration evolve differently: the use of sodium borohydride is limited by diffusion toward the surface, while adsorption on the surface of the sample is the rate-limiting step for lead tungstate. A direct link was established between the amount of stabilizer used and the surface of the sample; however, it cannot be applied to the use of sodium borohydride. A batch replenishment procedure for the electroless bath was developed by chemistry analysis at different stages of the plating process. This procedure allowed bath reuse and reduction of the number of new bath preparations. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132258
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9227-9234[article] Evolution of reactive concentration during borohydride - reduced electroless nickel – boron plating and design of a replenishment procedure [texte imprimé] / Véronique Vitry, Auteur ; Abdoul-Fatah Kanta, Auteur ; Fabienne Delaunois, Auteur . - 2012 . - pp. 9227-9234.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9227-9234
Mots-clés : Design Résumé : Electroless nickel―boron samples with 5 wt % boron were synthesized on mild steel with a bath based on sodium borohydride. Evolution of chemistry in the bath was followed during plating. Most reactive was consumed during the first half hour of the process. However, reducing agent and stabilizer concentration evolve differently: the use of sodium borohydride is limited by diffusion toward the surface, while adsorption on the surface of the sample is the rate-limiting step for lead tungstate. A direct link was established between the amount of stabilizer used and the surface of the sample; however, it cannot be applied to the use of sodium borohydride. A batch replenishment procedure for the electroless bath was developed by chemistry analysis at different stages of the plating process. This procedure allowed bath reuse and reduction of the number of new bath preparations. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132258 Exemplaires
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Titre : Toughening of polyamide - 6 with a maleic anhydride functionalized acrylonitrile - styrene - butyl acrylate copolymer Type de document : texte imprimé Auteurs : Zhenguo Liu, Auteur ; Yunjiao Deng, Auteur ; Ye Han, Auteur Année de publication : 2012 Article en page(s) : pp. 9235-9240 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Polyamide Résumé : Maleic anhydride (MAH) functionalized acrylate-styrene-acrylonitrile (ASA) copolymers (F-ASA) were prepared via an emulsion polymerization process. The F-ASA particles were used to toughen Polyamide-6 (PA-6). Molau tests showed the compatibilization reactions between PA-6 and F-ASA. The notched impact strength of PA-6 was effectively improved by the use of F-ASA. At a rubber content of 20% by weight in PA-6/F-ASA blends, it was found that the impact strength increased with the MAH content. When the MAH content was 8% in F-ASA, the impact strength was 1008 J/m. The influence of rubber content on the properties of PA-6/F-ASA8 blends was investigated. The results showed that brittle-ductile transition took place when the rubber content was 20%. Moreover, increasing the MAH content of the blends reduced the brittle-ductile temperature of the F-ASA/PA-6 blends from 50 °C to about 0 °C. Scanning electron microscopy (SEM) results showed that cavitation of rubber particles and shear yielding of the PA-6 matrix were the major toughening mechanisms. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202960q
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9235-9240[article] Toughening of polyamide - 6 with a maleic anhydride functionalized acrylonitrile - styrene - butyl acrylate copolymer [texte imprimé] / Zhenguo Liu, Auteur ; Yunjiao Deng, Auteur ; Ye Han, Auteur . - 2012 . - pp. 9235-9240.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9235-9240
Mots-clés : Polyamide Résumé : Maleic anhydride (MAH) functionalized acrylate-styrene-acrylonitrile (ASA) copolymers (F-ASA) were prepared via an emulsion polymerization process. The F-ASA particles were used to toughen Polyamide-6 (PA-6). Molau tests showed the compatibilization reactions between PA-6 and F-ASA. The notched impact strength of PA-6 was effectively improved by the use of F-ASA. At a rubber content of 20% by weight in PA-6/F-ASA blends, it was found that the impact strength increased with the MAH content. When the MAH content was 8% in F-ASA, the impact strength was 1008 J/m. The influence of rubber content on the properties of PA-6/F-ASA8 blends was investigated. The results showed that brittle-ductile transition took place when the rubber content was 20%. Moreover, increasing the MAH content of the blends reduced the brittle-ductile temperature of the F-ASA/PA-6 blends from 50 °C to about 0 °C. Scanning electron microscopy (SEM) results showed that cavitation of rubber particles and shear yielding of the PA-6 matrix were the major toughening mechanisms. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202960q Exemplaires
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Titre : Fabrication and characterization of PLLA /chitosan / nano calcium phosphate scaffolds by freeze - casting technique Type de document : texte imprimé Auteurs : Mahboubeh Jafarkhani, Auteur ; Alireza Fazlali, Auteur ; Fathollah Moztarzadeh, Auteur Année de publication : 2012 Article en page(s) : pp. 9241-9249 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Casting Résumé : In this research, nanocomposite scaffolds of chitosan/PLLA/nano calcium phosphate (average crystallite size of 16.5 nm) have been prepared via the freeze-casting method and then characterized. The effects of nano powder contents on the structure of scaffolds were investigated to provide an appropriate nanocomposite for bone tissue engineering applications. The results showed that the scaffolds had high porosity (up to 98%) with open pores of 80-380 μm in diameter. It was also shown that the porosity increased with decreasing nano powder content. Furthermore, the bioactive nano calcium phosphate was homogenously distributed within the polymeric matrix of scaffolds, which contained up to 40% of nano powder. Microstructure studies showed that the pores were distributed very well throughout the structures. This macropores structure with interconnected pores provides the properties of scaffolds required for bone tissue engineering applications. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132260
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9241-9249[article] Fabrication and characterization of PLLA /chitosan / nano calcium phosphate scaffolds by freeze - casting technique [texte imprimé] / Mahboubeh Jafarkhani, Auteur ; Alireza Fazlali, Auteur ; Fathollah Moztarzadeh, Auteur . - 2012 . - pp. 9241-9249.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9241-9249
Mots-clés : Casting Résumé : In this research, nanocomposite scaffolds of chitosan/PLLA/nano calcium phosphate (average crystallite size of 16.5 nm) have been prepared via the freeze-casting method and then characterized. The effects of nano powder contents on the structure of scaffolds were investigated to provide an appropriate nanocomposite for bone tissue engineering applications. The results showed that the scaffolds had high porosity (up to 98%) with open pores of 80-380 μm in diameter. It was also shown that the porosity increased with decreasing nano powder content. Furthermore, the bioactive nano calcium phosphate was homogenously distributed within the polymeric matrix of scaffolds, which contained up to 40% of nano powder. Microstructure studies showed that the pores were distributed very well throughout the structures. This macropores structure with interconnected pores provides the properties of scaffolds required for bone tissue engineering applications. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132260 Exemplaires
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Titre : Coating of open cell foams Type de document : texte imprimé Auteurs : Heng Zhang, Auteur ; Wieslaw J. Suszynski, Auteur ; Kumar Varoon Agrawal, Auteur Année de publication : 2012 Article en page(s) : pp. 9250–9259 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Carbon foams Résumé : The interior surfaces of three-dimensional open cell foams were coated by a combination of dip coating and spin coating. Glycerol/water solutions were used as model Newtonian liquids, and the coating processes were studied on open cell carbon foams with 10 or 30 pores per inch (PPI). The amount of liquid retained in the foam structures after dip coating increased with withdrawal speed and coating viscosity, as expected from the conventional understanding of dip coating onto nonporous substrates such as flat plates and rods. However, the liquid retention and hence average coating thickness increased with surface tension, a result counter to the observation with coating onto nonporous substrates. Pockets of liquid were observed after dip coating and results with coatings of alumina suspension showed that after drying, the trapped liquid can block pore windows. Spinning the foams after dip coating resulted in uniform liquid distribution and uniform coatings. Foams were placed in a special apparatus and rotated using a commercial spin coater. The liquid layer thickness decreased with spinning time and rotational speed, and increased with the liquid viscosity, results consistent with spin coating theory. The coating thickness after spinning was not affected by the initial dip coating procedure. The dip and spin process was also used to create γ-alumina and zeolite coatings, which are of interest for catalysis applications. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie300266p
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9250–9259[article] Coating of open cell foams [texte imprimé] / Heng Zhang, Auteur ; Wieslaw J. Suszynski, Auteur ; Kumar Varoon Agrawal, Auteur . - 2012 . - pp. 9250–9259.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9250–9259
Mots-clés : Carbon foams Résumé : The interior surfaces of three-dimensional open cell foams were coated by a combination of dip coating and spin coating. Glycerol/water solutions were used as model Newtonian liquids, and the coating processes were studied on open cell carbon foams with 10 or 30 pores per inch (PPI). The amount of liquid retained in the foam structures after dip coating increased with withdrawal speed and coating viscosity, as expected from the conventional understanding of dip coating onto nonporous substrates such as flat plates and rods. However, the liquid retention and hence average coating thickness increased with surface tension, a result counter to the observation with coating onto nonporous substrates. Pockets of liquid were observed after dip coating and results with coatings of alumina suspension showed that after drying, the trapped liquid can block pore windows. Spinning the foams after dip coating resulted in uniform liquid distribution and uniform coatings. Foams were placed in a special apparatus and rotated using a commercial spin coater. The liquid layer thickness decreased with spinning time and rotational speed, and increased with the liquid viscosity, results consistent with spin coating theory. The coating thickness after spinning was not affected by the initial dip coating procedure. The dip and spin process was also used to create γ-alumina and zeolite coatings, which are of interest for catalysis applications. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie300266p Exemplaires
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Titre : Synthesis of CO2 - philic polysiloxane with N - halamine side groups for biocidal coating on cotton Type de document : texte imprimé Auteurs : Chen, Yong, Auteur ; Xu-shi Zhong, Auteur ; Qiang Zhang, Auteur Année de publication : 2012 Article en page(s) : pp. 9260-9265 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Carbon dioxide Résumé : A CO2-philic antibacterial precursor was synthesized through hydrosilylation reaction of poly(methylhydrosiloxane) (PMHS) and tert-butyl acrylate in the presence of platinum-based catalyst. Carboxyl groups were then generated by hydrolyzing the precursor with trifluoroacetic acid to bond tert-butylamine molecules via amide bonds that were further chlorinated to N-halamines with tert-butyl hypochlorite. The resultant N-halamine polysiloxane was coated on cotton by adsorption from supercritical CO2 (scCO2) to confer biocidal ability. This coating procedure provides an efficient way to attach antibacterial polymers onto substrates without using covalent bonds which limit the structure designs. Presented data showed that the antibacterial layer was stable toward washing and abrasion and provided potent biocidal activities against Staphylococcus aureus and Escherichia coli. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132262
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9260-9265[article] Synthesis of CO2 - philic polysiloxane with N - halamine side groups for biocidal coating on cotton [texte imprimé] / Chen, Yong, Auteur ; Xu-shi Zhong, Auteur ; Qiang Zhang, Auteur . - 2012 . - pp. 9260-9265.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9260-9265
Mots-clés : Carbon dioxide Résumé : A CO2-philic antibacterial precursor was synthesized through hydrosilylation reaction of poly(methylhydrosiloxane) (PMHS) and tert-butyl acrylate in the presence of platinum-based catalyst. Carboxyl groups were then generated by hydrolyzing the precursor with trifluoroacetic acid to bond tert-butylamine molecules via amide bonds that were further chlorinated to N-halamines with tert-butyl hypochlorite. The resultant N-halamine polysiloxane was coated on cotton by adsorption from supercritical CO2 (scCO2) to confer biocidal ability. This coating procedure provides an efficient way to attach antibacterial polymers onto substrates without using covalent bonds which limit the structure designs. Presented data showed that the antibacterial layer was stable toward washing and abrasion and provided potent biocidal activities against Staphylococcus aureus and Escherichia coli. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132262 Exemplaires
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Titre : Determination of antiscaling efficiency and dissolution capacity for calcium carbonate with ultrasonic irradiation Type de document : texte imprimé Auteurs : Xiaoli Li, Auteur ; Jianguo Zhang, Auteur ; Daoyong Yang, Auteur Année de publication : 2012 Article en page(s) : pp. 9266–9274 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Calcium carbonate Ultrasonic irradiation Résumé : A systematic technique has been developed to determine antiscaling efficiency and dissolution capacity for calcium carbonate in oilfield brines under various ultrasonic treating conditions. During the static experiments, effects of ultrasonic frequency, acoustic intensity, treating time, and water level on the antiscaling efficiency have been evaluated, while the underlying antiscaling mechanism is identified and determined. Physically, the formation of calcium carbonate is promoted as a result of the decreased molecular force and accelerated movement of salty ions under ultrasonic irradiation. Most of the formed scale is found to loosely suspend in the liquid, rather than tightly adhere to the solid surface. During the dynamic experiments, orthogonal tests have been designed to examine effects of interval time, treating time, and flow velocity on antiscaling efficiency. As for the dissolution experiment, dissolution capacity is measured to evaluate the effect of ultrasonic frequency on dissolution of the formed calcium carbonate. The antiscaling efficiency is found to achieve its maximum value of 81.1%, using the ultrasonic treatment with a frequency of 28 kHz, an acoustic intensity of 0.61 W/cm2, an interval time of 2 h, a treatment time of 15 min, and a flow velocity of 1.8 m/s. It is also found that dissolution capacity does not impose a dominant effect on scale prevention and that the highest dissolution capacity of 19.3% is obtained with an ultrasonic frequency of 28 kHz. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie300575v
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9266–9274[article] Determination of antiscaling efficiency and dissolution capacity for calcium carbonate with ultrasonic irradiation [texte imprimé] / Xiaoli Li, Auteur ; Jianguo Zhang, Auteur ; Daoyong Yang, Auteur . - 2012 . - pp. 9266–9274.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9266–9274
Mots-clés : Calcium carbonate Ultrasonic irradiation Résumé : A systematic technique has been developed to determine antiscaling efficiency and dissolution capacity for calcium carbonate in oilfield brines under various ultrasonic treating conditions. During the static experiments, effects of ultrasonic frequency, acoustic intensity, treating time, and water level on the antiscaling efficiency have been evaluated, while the underlying antiscaling mechanism is identified and determined. Physically, the formation of calcium carbonate is promoted as a result of the decreased molecular force and accelerated movement of salty ions under ultrasonic irradiation. Most of the formed scale is found to loosely suspend in the liquid, rather than tightly adhere to the solid surface. During the dynamic experiments, orthogonal tests have been designed to examine effects of interval time, treating time, and flow velocity on antiscaling efficiency. As for the dissolution experiment, dissolution capacity is measured to evaluate the effect of ultrasonic frequency on dissolution of the formed calcium carbonate. The antiscaling efficiency is found to achieve its maximum value of 81.1%, using the ultrasonic treatment with a frequency of 28 kHz, an acoustic intensity of 0.61 W/cm2, an interval time of 2 h, a treatment time of 15 min, and a flow velocity of 1.8 m/s. It is also found that dissolution capacity does not impose a dominant effect on scale prevention and that the highest dissolution capacity of 19.3% is obtained with an ultrasonic frequency of 28 kHz. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie300575v Exemplaires
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Titre : A minimum variance control theory perspective on supply chain lead time uncertainty Type de document : texte imprimé Auteurs : Hua Xu, Auteur ; Gang Rong, Auteur Année de publication : 2012 Article en page(s) : pp. 9275-9286 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Uncertainty Résumé : This paper addresses the lead time uncertainty problem in supply chain systems. In our previous paper [Xu et al. Ind. Eng. Chem. Res.2010,49,8644], we have investigated the impact of demand uncertainty on supply chains. Here we adopt a two-echelon supply chain model, which is basically the same as that used in the research of demand uncertainty. But the fixed lead time setting is replaced by a Markovian lead time model. Since the lead time varies with time, the dynamic characteristics of the supply chain model are different from that used in the demand uncertainty research. We make a comparison analysis of these differences from the view of dynamic systems. On the basis of the above analysis, we adopt two fundamental lemmas of the minimum variance control theory as the foundation for replenishment rules design and analysis. Then we derive formulas of the Order-up-to policy and the generalized Order-up-to policy with time-varying lead time. Moreover, we offer the variant forms of the above strategies when the lead time information is incomplete. Given the strategies, we analyze the influence of lead time information on the order and inventory variances and corresponding costs. This work, together with our previous paper on demand uncertainty, may provide a coherent control theory based perspective on these two different types of uncertainties in a supply chain. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132264
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9275-9286[article] A minimum variance control theory perspective on supply chain lead time uncertainty [texte imprimé] / Hua Xu, Auteur ; Gang Rong, Auteur . - 2012 . - pp. 9275-9286.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9275-9286
Mots-clés : Uncertainty Résumé : This paper addresses the lead time uncertainty problem in supply chain systems. In our previous paper [Xu et al. Ind. Eng. Chem. Res.2010,49,8644], we have investigated the impact of demand uncertainty on supply chains. Here we adopt a two-echelon supply chain model, which is basically the same as that used in the research of demand uncertainty. But the fixed lead time setting is replaced by a Markovian lead time model. Since the lead time varies with time, the dynamic characteristics of the supply chain model are different from that used in the demand uncertainty research. We make a comparison analysis of these differences from the view of dynamic systems. On the basis of the above analysis, we adopt two fundamental lemmas of the minimum variance control theory as the foundation for replenishment rules design and analysis. Then we derive formulas of the Order-up-to policy and the generalized Order-up-to policy with time-varying lead time. Moreover, we offer the variant forms of the above strategies when the lead time information is incomplete. Given the strategies, we analyze the influence of lead time information on the order and inventory variances and corresponding costs. This work, together with our previous paper on demand uncertainty, may provide a coherent control theory based perspective on these two different types of uncertainties in a supply chain. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132264 Exemplaires
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Titre : Short - term scheduling of refinery crude oil operations Type de document : texte imprimé Auteurs : Sanjeev Yadav, Auteur ; Munawar A. Shaik, Auteur Année de publication : 2012 Article en page(s) : pp. 9287–9299 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Refinery Oil operations Résumé : Scheduling of crude oil unloading and loading operations is an important optimization problem for minimizing the significant costs at the front end of a refinery. The scheduling problem involves finding the optimal operation of crude-oil unloading from vessels, its transfer to storage tanks, and determination of charging schedule for each crude-oil mixture to the continuous distillation units. In this work, we propose a simplified state-task-network (STN) based formulation to address the problem of short-term scheduling of crude oil operations using unit-specific event-based continuous-time representation by incorporating explicit storage tasks for handling material transfer from storage and charging tanks. Constraints are developed for different cases corresponding to material flow in a tank based on (i) whether bypassing is allowed or not, (ii) whether crude mixing is allowed or not, and based on (iii) whether simultaneous input and output is allowed or not. The proposed model is applied to a few benchmark examples from literature giving better results with improved objective functions compared with the results reported in previous works. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie300046g
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9287–9299[article] Short - term scheduling of refinery crude oil operations [texte imprimé] / Sanjeev Yadav, Auteur ; Munawar A. Shaik, Auteur . - 2012 . - pp. 9287–9299.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9287–9299
Mots-clés : Refinery Oil operations Résumé : Scheduling of crude oil unloading and loading operations is an important optimization problem for minimizing the significant costs at the front end of a refinery. The scheduling problem involves finding the optimal operation of crude-oil unloading from vessels, its transfer to storage tanks, and determination of charging schedule for each crude-oil mixture to the continuous distillation units. In this work, we propose a simplified state-task-network (STN) based formulation to address the problem of short-term scheduling of crude oil operations using unit-specific event-based continuous-time representation by incorporating explicit storage tasks for handling material transfer from storage and charging tanks. Constraints are developed for different cases corresponding to material flow in a tank based on (i) whether bypassing is allowed or not, (ii) whether crude mixing is allowed or not, and based on (iii) whether simultaneous input and output is allowed or not. The proposed model is applied to a few benchmark examples from literature giving better results with improved objective functions compared with the results reported in previous works. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie300046g Exemplaires
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Titre : Incorporating sustainability into the conceptual design of chemical process - reaction routes selection Type de document : texte imprimé Auteurs : Kailiang Zheng, Auteur ; Helen H. Lou, Auteur ; Preeti Gangadharan, Auteur Année de publication : 2012 Article en page(s) : pp. 9300-9309 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Design Sustainable development Résumé : Limited availability of natural resources and rising raw material cost, accompanied by growing societal and environmental concerns, urge the engineers to incorporate sustainability issues into the design of new chemical process and the retrofit of traditional process. Yet due to the multidimensional nature of sustainability, as economic, societal, and environmental issues need to be considered together, a structured sustainability assessment tool is needed to serve as the basis for any process design, analysis, improvement, and decision making. This paper presents a methodology to assist reaction pathway selection in light of sustainability. At this conceptual design stage, the sustainability performance of different potential reaction pathways is evaluated, which can not only help the designers improve the screening efficiency by eliminating inferior reaction alternatives systematically, but also identify the key areas for further improvement in future design, thus reducing the complexity and labor in the following basic engineering design stage. The sustainability of each reaction pathway is assessed in terms of profit potential, driving force of the pathway (Gibbs free energy), inherent safety index, potential environmental index, and atom economy. The efficacy of this approach is demonstrated by several case studies of reaction routes selection, including the propylene oxide (PO) production process, carbon dioxide reduction technology, and cellulosic ethanol production technology. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132266
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9300-9309[article] Incorporating sustainability into the conceptual design of chemical process - reaction routes selection [texte imprimé] / Kailiang Zheng, Auteur ; Helen H. Lou, Auteur ; Preeti Gangadharan, Auteur . - 2012 . - pp. 9300-9309.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9300-9309
Mots-clés : Design Sustainable development Résumé : Limited availability of natural resources and rising raw material cost, accompanied by growing societal and environmental concerns, urge the engineers to incorporate sustainability issues into the design of new chemical process and the retrofit of traditional process. Yet due to the multidimensional nature of sustainability, as economic, societal, and environmental issues need to be considered together, a structured sustainability assessment tool is needed to serve as the basis for any process design, analysis, improvement, and decision making. This paper presents a methodology to assist reaction pathway selection in light of sustainability. At this conceptual design stage, the sustainability performance of different potential reaction pathways is evaluated, which can not only help the designers improve the screening efficiency by eliminating inferior reaction alternatives systematically, but also identify the key areas for further improvement in future design, thus reducing the complexity and labor in the following basic engineering design stage. The sustainability of each reaction pathway is assessed in terms of profit potential, driving force of the pathway (Gibbs free energy), inherent safety index, potential environmental index, and atom economy. The efficacy of this approach is demonstrated by several case studies of reaction routes selection, including the propylene oxide (PO) production process, carbon dioxide reduction technology, and cellulosic ethanol production technology. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132266 Exemplaires
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Titre : Heuristic dynamic programming algorithm for optimal control design of linear continuous - time hyperbolic PDE systems Type de document : texte imprimé Auteurs : Huai-Ning Wu, Auteur ; Biao Luo, Auteur Année de publication : 2012 Article en page(s) : pp. 9310-9319 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Mathematical programming Continuous time Design Optimal control Algorithm Dynamic Résumé : This work considers the optimal control problem of linear continuous-time hyperbolic partial differential equation (PDE) systems with partially unknown system dynamics. To respect the infinite-dimensional nature of the hyperbolic PDE system, the problem can be reduced to finding a solution of the space-dependent Riccati differential equation (SDRDE), which requires the full system model. Therefore, a heuristic dynamic programming (HDP) algorithm is proposed to achieve online optimal control of the hyperbolic PDE system, which online collects data accrued along system trajectories and learns the solution of the SDRDE without requiring the internal system dynamics. The convergence of HDP algorithm is established by showing that the HDP algorithm generates a nondecreasing sequence which uniformly converges to the solution of the SDRDE. For implementation purposes, the HDP algorithm is realized by developing an approximate approach based on the method of weighted residuals. Finally, the application on a steam-jacketed tubular heat exchanger demonstrates the effectiveness of the developed control approach. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132267
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9310-9319[article] Heuristic dynamic programming algorithm for optimal control design of linear continuous - time hyperbolic PDE systems [texte imprimé] / Huai-Ning Wu, Auteur ; Biao Luo, Auteur . - 2012 . - pp. 9310-9319.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9310-9319
Mots-clés : Mathematical programming Continuous time Design Optimal control Algorithm Dynamic Résumé : This work considers the optimal control problem of linear continuous-time hyperbolic partial differential equation (PDE) systems with partially unknown system dynamics. To respect the infinite-dimensional nature of the hyperbolic PDE system, the problem can be reduced to finding a solution of the space-dependent Riccati differential equation (SDRDE), which requires the full system model. Therefore, a heuristic dynamic programming (HDP) algorithm is proposed to achieve online optimal control of the hyperbolic PDE system, which online collects data accrued along system trajectories and learns the solution of the SDRDE without requiring the internal system dynamics. The convergence of HDP algorithm is established by showing that the HDP algorithm generates a nondecreasing sequence which uniformly converges to the solution of the SDRDE. For implementation purposes, the HDP algorithm is realized by developing an approximate approach based on the method of weighted residuals. Finally, the application on a steam-jacketed tubular heat exchanger demonstrates the effectiveness of the developed control approach. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132267 Exemplaires
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Titre : A high temperature lithium orthosilicate - based solid absorbent for post combustion CO2 capture Type de document : texte imprimé Auteurs : Robert Quinn, Auteur ; Ronald J. Kitzhoffer, Auteur ; Jeffrey R. Hufton, Auteur Année de publication : 2012 Article en page(s) : pp. 9320-9327 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Carbon dioxide Combustion Absorbent Résumé : Capture of carbon dioxide from combustion processes presents a unique and challenging technical problem arising from low CO2 partial pressures, high flow rates, and the presence of water vapor and reactive contaminants such as SO2. A series of solid sorbents were evaluated to determine suitability for postcombustion capture. A lithium orthosilicate (Li4SiO4)-based absorbent supplied by Toshiba Corporation was found to have the most promising properties. The absorbent reacts chemically with CO2 at elevated temperatures (550 °C) to form lithium carbonate (Li2CO3) and lithium metasilicate (Li2SiO3). The presence of water vapor was shown to greatly enhance CO2 absorption rates without affecting capacity. Breakthrough capacities of ∼5―6 mmol/g (22-26 wt %) were obtained using a "clean" synthetic flue gas containing 15% CO2 and 10% H2O in N2 at 550 °C. Experimental studies showed that the absorbent used in a fixed bed process will likely require a thermal swing process with absorption at 550 °C and regeneration at 650 °C. Even for the high capacity of the Li4SiO4-based absorbent, an alternative to conventional fixed bed technology will be required for practical postcombustion capture from coal-fired power plants. Processes that can shorten cycle times by rapidly heating and cooling vessels and/or sorbents will be needed, and possible alternatives are described. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132268
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9320-9327[article] A high temperature lithium orthosilicate - based solid absorbent for post combustion CO2 capture [texte imprimé] / Robert Quinn, Auteur ; Ronald J. Kitzhoffer, Auteur ; Jeffrey R. Hufton, Auteur . - 2012 . - pp. 9320-9327.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9320-9327
Mots-clés : Carbon dioxide Combustion Absorbent Résumé : Capture of carbon dioxide from combustion processes presents a unique and challenging technical problem arising from low CO2 partial pressures, high flow rates, and the presence of water vapor and reactive contaminants such as SO2. A series of solid sorbents were evaluated to determine suitability for postcombustion capture. A lithium orthosilicate (Li4SiO4)-based absorbent supplied by Toshiba Corporation was found to have the most promising properties. The absorbent reacts chemically with CO2 at elevated temperatures (550 °C) to form lithium carbonate (Li2CO3) and lithium metasilicate (Li2SiO3). The presence of water vapor was shown to greatly enhance CO2 absorption rates without affecting capacity. Breakthrough capacities of ∼5―6 mmol/g (22-26 wt %) were obtained using a "clean" synthetic flue gas containing 15% CO2 and 10% H2O in N2 at 550 °C. Experimental studies showed that the absorbent used in a fixed bed process will likely require a thermal swing process with absorption at 550 °C and regeneration at 650 °C. Even for the high capacity of the Li4SiO4-based absorbent, an alternative to conventional fixed bed technology will be required for practical postcombustion capture from coal-fired power plants. Processes that can shorten cycle times by rapidly heating and cooling vessels and/or sorbents will be needed, and possible alternatives are described. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132268 Exemplaires
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Titre : Effect of pH, CO2, and high glucose concentrations on polydimethylsiloxane pervaporation membranes for ethanol removal Type de document : texte imprimé Auteurs : Diana Maria Aguilar-Valencia, Auteur ; Miguel Angel Gomez-Garcia, Auteur ; Javier Fontalvo, Auteur Année de publication : 2012 Article en page(s) : pp. 9328–9334 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Pervaporation membranes Ethanol Résumé : Previous studies have shown that hybrid fermentation–pervaporation systems can be attractive for ethanol production. Simultaneous removal of the ethanol produced promises to improve yield and to reduce operation time and the energy required for ethanol purification. This paper experimentally explores the effect of pH (3–5.7), CO2 (at saturated conditions), and high glucose concentrations (50–400 g/L) on the flux and selectivity of PDMS (polydimethylsiloxane) pervaporation membranes at several ethanol concentrations (50–100 g/L) and temperatures (278–313 K). Membrane performance has been simulated using a Henry solution model combined with a Maxwell–Stefan description of mass transport through the membrane. By adjusting the model to the water–ethanol experimental data, it was possible to calculate the relative solubility and diffusion between ethanol and water in the polymeric membrane. Experimental results showed that the higher the glucose concentration is, the higher the membrane selectivity to ethanol will be due to a reduction on water flux. However, at a glucose concentration of 400 g/L a strong drop of total flux was measured. CO2 permeates through the PDMS membrane, but it does not have any effect on ethanol or water flux and, consequently, on selectivity. On the contrary, as pH is reduced so does selectivity while the total flux increases. Low pH values produce a decrease in membrane hydrophobicity, increasing water transport. The results presented in this paper contribute to the design of hybrid fermentation and pervaporation units, especially those that can operate at high glucose concentrations. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3002765
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9328–9334[article] Effect of pH, CO2, and high glucose concentrations on polydimethylsiloxane pervaporation membranes for ethanol removal [texte imprimé] / Diana Maria Aguilar-Valencia, Auteur ; Miguel Angel Gomez-Garcia, Auteur ; Javier Fontalvo, Auteur . - 2012 . - pp. 9328–9334.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9328–9334
Mots-clés : Pervaporation membranes Ethanol Résumé : Previous studies have shown that hybrid fermentation–pervaporation systems can be attractive for ethanol production. Simultaneous removal of the ethanol produced promises to improve yield and to reduce operation time and the energy required for ethanol purification. This paper experimentally explores the effect of pH (3–5.7), CO2 (at saturated conditions), and high glucose concentrations (50–400 g/L) on the flux and selectivity of PDMS (polydimethylsiloxane) pervaporation membranes at several ethanol concentrations (50–100 g/L) and temperatures (278–313 K). Membrane performance has been simulated using a Henry solution model combined with a Maxwell–Stefan description of mass transport through the membrane. By adjusting the model to the water–ethanol experimental data, it was possible to calculate the relative solubility and diffusion between ethanol and water in the polymeric membrane. Experimental results showed that the higher the glucose concentration is, the higher the membrane selectivity to ethanol will be due to a reduction on water flux. However, at a glucose concentration of 400 g/L a strong drop of total flux was measured. CO2 permeates through the PDMS membrane, but it does not have any effect on ethanol or water flux and, consequently, on selectivity. On the contrary, as pH is reduced so does selectivity while the total flux increases. Low pH values produce a decrease in membrane hydrophobicity, increasing water transport. The results presented in this paper contribute to the design of hybrid fermentation and pervaporation units, especially those that can operate at high glucose concentrations. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3002765 Exemplaires
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Titre : Synergy of electrochemical / O3 process with aluminum electrodes in industrial wastewater treatment Type de document : texte imprimé Auteurs : Carlos Barrera-Díaz, Auteur ; Lina. A. Bernal-Martinez, Auteur ; Reyna Natividad, Auteur Année de publication : 2012 Article en page(s) : pp. 9335–9342 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Electrochemical Electrodes Résumé : This study aimed to evaluate the effects of pH (3–9) and current density (16–66 mA/cm2) on the removal of COD, color, and turbidity with electrochemical, ozonation, and combined electrochemical/ozonation processes. Regarding the electrochemical process, under optimal conditions of pH 9 and a current density of 66 mA/cm2, the chemical oxygen demand (COD) was reduced by 44% after 30 min. The ozonation treatment was found to be more effective at pH 9 and reduced 63% of the original COD after only 12.5 min of treatment. Combining the electrochemical and ozonation processes resulted in a synergy that enhanced the removal of all three contaminants (COD, color, and turbidity). A COD removal of 79% (170 mg/L) was attained after only 12.5 min and at relatively low current density. Thus, the combination of the electrochemical and ozonation processes is able to noticeably improve wastewater quality. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3004144
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9335–9342[article] Synergy of electrochemical / O3 process with aluminum electrodes in industrial wastewater treatment [texte imprimé] / Carlos Barrera-Díaz, Auteur ; Lina. A. Bernal-Martinez, Auteur ; Reyna Natividad, Auteur . - 2012 . - pp. 9335–9342.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9335–9342
Mots-clés : Electrochemical Electrodes Résumé : This study aimed to evaluate the effects of pH (3–9) and current density (16–66 mA/cm2) on the removal of COD, color, and turbidity with electrochemical, ozonation, and combined electrochemical/ozonation processes. Regarding the electrochemical process, under optimal conditions of pH 9 and a current density of 66 mA/cm2, the chemical oxygen demand (COD) was reduced by 44% after 30 min. The ozonation treatment was found to be more effective at pH 9 and reduced 63% of the original COD after only 12.5 min of treatment. Combining the electrochemical and ozonation processes resulted in a synergy that enhanced the removal of all three contaminants (COD, color, and turbidity). A COD removal of 79% (170 mg/L) was attained after only 12.5 min and at relatively low current density. Thus, the combination of the electrochemical and ozonation processes is able to noticeably improve wastewater quality. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3004144 Exemplaires
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Titre : New approach for modeling hybrid pressure swing adsorption – distillation processes Type de document : texte imprimé Auteurs : James A. Ritter, Auteur ; Fan Wu, Auteur ; Armin D. Ebner, Auteur Année de publication : 2012 Article en page(s) : pp. 9343-9355 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Distillation Pressure swing adsorption Modeling Résumé : A new methodology for modeling hybrid pressure swing adsorption (PSA)―distillation processes has been developed. This new approach involves two parts. Part I determines if energy savings are possible. It can be done easily with sufficient knowledge of distillation process design, but with only minimal knowledge of PSA process design. Part I is carried out using a distillation process simulator such as Chemsep to model a distillation column connected to a PSA unit that is treated as a "black box" with an assumed process performance. In this way, a hybrid PSA―distillation process can be analyzed simply by performing mass balances around these units and running Chemsep to determine if energy savings are possible compared to a reference (commercial) process. Once an energy savings hybrid "black box" PSA―distillation process is found in part I, part II determines if an "actual" PSA process exists that mimics its performance. Part II is carried out using a rigorous PSA process simulator such as Adsim from AspenTech; thus, it requires significant knowledge of PSA process design. The outcome of part II is a hybrid PSA―distillation process that has the potential to be more energy efficient than the reference process. This new approach was successfully demonstrated using the commercial hybrid PSA―distillation process developed for fuel grade ethanol production as the reference case. This two-part analysis found several, more energy efficient designs than the reference case. All of them had proportionately reduced internal vapor and liquid flows in the distillation column, a direct effect of reducing condenser or reboiler duty. These results illustrated that the new methodology should be very useful for quickly accessing the utility of hybrid PSA―distillation processes for a variety of other applications, with many possibilities for achieving significant energy savings and/or throughput debottlenecking. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132271
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9343-9355[article] New approach for modeling hybrid pressure swing adsorption – distillation processes [texte imprimé] / James A. Ritter, Auteur ; Fan Wu, Auteur ; Armin D. Ebner, Auteur . - 2012 . - pp. 9343-9355.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9343-9355
Mots-clés : Distillation Pressure swing adsorption Modeling Résumé : A new methodology for modeling hybrid pressure swing adsorption (PSA)―distillation processes has been developed. This new approach involves two parts. Part I determines if energy savings are possible. It can be done easily with sufficient knowledge of distillation process design, but with only minimal knowledge of PSA process design. Part I is carried out using a distillation process simulator such as Chemsep to model a distillation column connected to a PSA unit that is treated as a "black box" with an assumed process performance. In this way, a hybrid PSA―distillation process can be analyzed simply by performing mass balances around these units and running Chemsep to determine if energy savings are possible compared to a reference (commercial) process. Once an energy savings hybrid "black box" PSA―distillation process is found in part I, part II determines if an "actual" PSA process exists that mimics its performance. Part II is carried out using a rigorous PSA process simulator such as Adsim from AspenTech; thus, it requires significant knowledge of PSA process design. The outcome of part II is a hybrid PSA―distillation process that has the potential to be more energy efficient than the reference process. This new approach was successfully demonstrated using the commercial hybrid PSA―distillation process developed for fuel grade ethanol production as the reference case. This two-part analysis found several, more energy efficient designs than the reference case. All of them had proportionately reduced internal vapor and liquid flows in the distillation column, a direct effect of reducing condenser or reboiler duty. These results illustrated that the new methodology should be very useful for quickly accessing the utility of hybrid PSA―distillation processes for a variety of other applications, with many possibilities for achieving significant energy savings and/or throughput debottlenecking. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132271 Exemplaires
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Titre : Generation of air – water two - phase flow patterns by altering the helix angle in triple helical microchannels Type de document : texte imprimé Auteurs : Sambasiva Rao Ganneboyina, Auteur ; Animangsu Ghatak, Auteur Année de publication : 2012 Article en page(s) : pp. 9356–9364 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Phase flow Microchannels Résumé : Flow of a liquid inside a helical tube is composed of axial and circumferential components, the latter arising because of its specific geometry. For a gas–liquid two-phase flow inside a helical tube, the coupled effect of these two flow components leads to a variety of flow patterns, for example, slug, bubble, and stratified flow. We present here a novel triple-helical microchannel, in which, the two-phase flow is found to engender several additional flow patterns not observed with the conventional geometries, for example, the parallel and oscillating annular flow and even simultaneous occurrence of several such patterns. We show that the transition between these patterns depends not only on the fluid rates of the two liquids but also on the helix angle. We have presented detailed phase diagrams to elaborate these effects. We have examined also the effect of channel geometry on the specific features of these flow patterns. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201249g
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9356–9364[article] Generation of air – water two - phase flow patterns by altering the helix angle in triple helical microchannels [texte imprimé] / Sambasiva Rao Ganneboyina, Auteur ; Animangsu Ghatak, Auteur . - 2012 . - pp. 9356–9364.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9356–9364
Mots-clés : Phase flow Microchannels Résumé : Flow of a liquid inside a helical tube is composed of axial and circumferential components, the latter arising because of its specific geometry. For a gas–liquid two-phase flow inside a helical tube, the coupled effect of these two flow components leads to a variety of flow patterns, for example, slug, bubble, and stratified flow. We present here a novel triple-helical microchannel, in which, the two-phase flow is found to engender several additional flow patterns not observed with the conventional geometries, for example, the parallel and oscillating annular flow and even simultaneous occurrence of several such patterns. We show that the transition between these patterns depends not only on the fluid rates of the two liquids but also on the helix angle. We have presented detailed phase diagrams to elaborate these effects. We have examined also the effect of channel geometry on the specific features of these flow patterns. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201249g Exemplaires
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Titre : Structure and diffusion behavior of trioctyl trimellitate (TOTM) in PVC film studied by ATR - IR spectroscopy Type de document : texte imprimé Auteurs : Hengjie Lai, Auteur ; Zhangwei Wang, Auteur ; Peiyi Wu, Auteur Année de publication : 2012 Article en page(s) : pp. 9365-9375 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Diffusion Résumé : Tri-2-ethylhexyltrimellitate (TOTM) is one of the commercially used plasticizers for poly(vinyl chloride) (PVC). In this work, the diffusion behavior of TOTM in PVC films is investigated through real-time ATR-IR spectroscopy at 25, 40, and 70 °C, and the ratio changes of three C═O structures of TOTM are plotted as a function of diffusion time. TOTM itself is composed of two types of C═O structures: one C═O structure represents a free state and the other represents an aggregated C═O state formed by dipolar–dipolar interactions, as confirmed by the second derivative of FTIR and density functional theory (DFT). Furthermore, another new band related to C═O groups of TOTM was observed during diffusion experiments in PVC at different temperatures, which can be assigned to dipolar–dipolar interactions between TOTM and PVC (interacting C═O structure). These results show that the diffusion coefficients of TOTM in PVC increase with temperature. Conversely, the equilibrium concentrations of TOTM in PVC films decrease significantly with temperature due to rapid molecular movements and less interacting C═O structures. Moreover, it is also found that free C═O structures more easily interact with C–Cl groups of PVC at 25 °C, while aggregated C═O structures show prior contribution at 40 °C, which is effectively confirmed by two-dimensional (2D) correlation infrared spectroscopy. At 70 °C, however, free and aggregated C═O structures can reach an equilibrium much more quickly, but the content of interacting C═O structures has to keep a lower level because of higher temperature. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132273
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9365-9375[article] Structure and diffusion behavior of trioctyl trimellitate (TOTM) in PVC film studied by ATR - IR spectroscopy [texte imprimé] / Hengjie Lai, Auteur ; Zhangwei Wang, Auteur ; Peiyi Wu, Auteur . - 2012 . - pp. 9365-9375.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9365-9375
Mots-clés : Diffusion Résumé : Tri-2-ethylhexyltrimellitate (TOTM) is one of the commercially used plasticizers for poly(vinyl chloride) (PVC). In this work, the diffusion behavior of TOTM in PVC films is investigated through real-time ATR-IR spectroscopy at 25, 40, and 70 °C, and the ratio changes of three C═O structures of TOTM are plotted as a function of diffusion time. TOTM itself is composed of two types of C═O structures: one C═O structure represents a free state and the other represents an aggregated C═O state formed by dipolar–dipolar interactions, as confirmed by the second derivative of FTIR and density functional theory (DFT). Furthermore, another new band related to C═O groups of TOTM was observed during diffusion experiments in PVC at different temperatures, which can be assigned to dipolar–dipolar interactions between TOTM and PVC (interacting C═O structure). These results show that the diffusion coefficients of TOTM in PVC increase with temperature. Conversely, the equilibrium concentrations of TOTM in PVC films decrease significantly with temperature due to rapid molecular movements and less interacting C═O structures. Moreover, it is also found that free C═O structures more easily interact with C–Cl groups of PVC at 25 °C, while aggregated C═O structures show prior contribution at 40 °C, which is effectively confirmed by two-dimensional (2D) correlation infrared spectroscopy. At 70 °C, however, free and aggregated C═O structures can reach an equilibrium much more quickly, but the content of interacting C═O structures has to keep a lower level because of higher temperature. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132273 Exemplaires
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Titre : Sifting ionic liquids as additives for separation of acetonitrile and water azeotropic mixture using the COSMO - RS method Type de document : texte imprimé Auteurs : Jinlong Li, Auteur ; Xiaoqian Yang, Auteur ; Kexia Chen, Auteur Année de publication : 2012 Article en page(s) : pp. 9376-9385 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Azeotropic mixture Additive Ionic liquid Résumé : The phase behavior of the ternary acetonitrile + water + ionic liquid system was predicted using the COSMO-RS method. The effects of different ionic liquids on the separation of acetonitrile + water were discussed. It was found that the influence of anions [OAc]― and [Cl]― on the acetonitrile + water mixture is strong, while the cations have fewer effects on the mixture. The interaction energies and mixing enthalpies of binary acetonitrile + ionic liquid and water + ionic liquid systems were predicted indicating that the interaction energy between molecules is stronger in the water + ionic liquid mixture than in the acetonitrile + ionic liquid system. The excess enthalpies of binary mixtures mainly depend on the hydrogen bonds formed between water (or acetonitrile) and ionic liquids. Ionic liquids [EMIM][OAc] and [EMIM]Cl are expected to be favorable solvents and supposed to have practical applications in the separation of acetonitrile from aqueous solution. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132274
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9376-9385[article] Sifting ionic liquids as additives for separation of acetonitrile and water azeotropic mixture using the COSMO - RS method [texte imprimé] / Jinlong Li, Auteur ; Xiaoqian Yang, Auteur ; Kexia Chen, Auteur . - 2012 . - pp. 9376-9385.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9376-9385
Mots-clés : Azeotropic mixture Additive Ionic liquid Résumé : The phase behavior of the ternary acetonitrile + water + ionic liquid system was predicted using the COSMO-RS method. The effects of different ionic liquids on the separation of acetonitrile + water were discussed. It was found that the influence of anions [OAc]― and [Cl]― on the acetonitrile + water mixture is strong, while the cations have fewer effects on the mixture. The interaction energies and mixing enthalpies of binary acetonitrile + ionic liquid and water + ionic liquid systems were predicted indicating that the interaction energy between molecules is stronger in the water + ionic liquid mixture than in the acetonitrile + ionic liquid system. The excess enthalpies of binary mixtures mainly depend on the hydrogen bonds formed between water (or acetonitrile) and ionic liquids. Ionic liquids [EMIM][OAc] and [EMIM]Cl are expected to be favorable solvents and supposed to have practical applications in the separation of acetonitrile from aqueous solution. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132274 Exemplaires
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Titre : Investigation of convective heat transfer with liquids in microtubes Type de document : texte imprimé Auteurs : Ke-Jun Wu, Auteur ; Chun-Xia Zhao, Auteur ; Guo-Hua Xu, Auteur Année de publication : 2012 Article en page(s) : pp. 9386-9395 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Heat transfer Résumé : Convective heat transfer in microtubes has attracted considerable attention for almost three decades. It is well-known that the solid―liquid interfacial tension plays an important role at the micrometer length scale. In this work, the characteristics of convective heat transfer in microtubes with inner diameters ranging from 0.353 to 1.045 mm were investigated; the effects of interfacial tension on heat transfer were also investigated using nine working fluids (including deionized water, 5 wt % ethanol aqueous solution, 50 wt % ethanol aqueous solution, ethanol, ethyl acetate, cyclohexane, n-hexane, cyclohexanone, and cyclopentanone). The experimental results showed that the performance of convective heat transfer of different working fluids in microtubes varied significantly and was different from that in conventional scale tubes. The results were correlated by an empirical correlation, in which the effect of solid―liquid interfacial tension was taken into account. The agreement between the correlation and the experimental data was found to be satisfactory. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132275
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9386-9395[article] Investigation of convective heat transfer with liquids in microtubes [texte imprimé] / Ke-Jun Wu, Auteur ; Chun-Xia Zhao, Auteur ; Guo-Hua Xu, Auteur . - 2012 . - pp. 9386-9395.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9386-9395
Mots-clés : Heat transfer Résumé : Convective heat transfer in microtubes has attracted considerable attention for almost three decades. It is well-known that the solid―liquid interfacial tension plays an important role at the micrometer length scale. In this work, the characteristics of convective heat transfer in microtubes with inner diameters ranging from 0.353 to 1.045 mm were investigated; the effects of interfacial tension on heat transfer were also investigated using nine working fluids (including deionized water, 5 wt % ethanol aqueous solution, 50 wt % ethanol aqueous solution, ethanol, ethyl acetate, cyclohexane, n-hexane, cyclohexanone, and cyclopentanone). The experimental results showed that the performance of convective heat transfer of different working fluids in microtubes varied significantly and was different from that in conventional scale tubes. The results were correlated by an empirical correlation, in which the effect of solid―liquid interfacial tension was taken into account. The agreement between the correlation and the experimental data was found to be satisfactory. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132275 Exemplaires
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Titre : Upper flammability limits of hydrogen and light hydrocarbons in air at subatmospheric pressures Type de document : texte imprimé Auteurs : Hai Le, Auteur ; Subramanya Nayak, Auteur ; M. Sam Mannan, Auteur Année de publication : 2012 Article en page(s) : pp. 9396-9402 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Subatmospheric pressure Flammability limit Résumé : The upper flammability limits (UFL) of hydrogen―air, methane―air, ethane―air, n-butane―air, and ethylene―air were determined experimentally at room temperature (20 °C) and initial pressure of 1.0, 0.7, 0.5, 0.3, 0.1, and 0.05 atm. Experiments were conducted in a closed cylindrical stainless steel vessel (i.d. 10.22 cm, length 100 cm) with upward flame propagation. The UFL of hydrogen was observed to be inversely proportional to the initial pressure in the range from 1.0 to 0.3 atm and proportional to the initial pressure from 0.3 to 0.05 atm. In contrast, the UFLs of the lower alkanes and ethylene decreased with the initial pressure. The average flame propagation velocities at UFL concentrations of hydrogen, methane, ethane, n-butane, and ethylene in air at reduced pressures were also examined. It was found that the flame propagation velocity of hydrogen was larger than those of the hydrocarbons, increased when the initial pressure decreased from 1.0 to 0.3 atm, and then decreased with further decrease of pressure. Flame propagation velocities at UFL concentrations of the hydrocarbons decreased with the initial pressure. Finally, based on the behavior of the UFLs and flame propagation velocities, the relative risk and hazards of ignition and flame escalation of hydrogen and the light hydrocarbons at subatmospheric pressures were discussed. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132276
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9396-9402[article] Upper flammability limits of hydrogen and light hydrocarbons in air at subatmospheric pressures [texte imprimé] / Hai Le, Auteur ; Subramanya Nayak, Auteur ; M. Sam Mannan, Auteur . - 2012 . - pp. 9396-9402.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9396-9402
Mots-clés : Subatmospheric pressure Flammability limit Résumé : The upper flammability limits (UFL) of hydrogen―air, methane―air, ethane―air, n-butane―air, and ethylene―air were determined experimentally at room temperature (20 °C) and initial pressure of 1.0, 0.7, 0.5, 0.3, 0.1, and 0.05 atm. Experiments were conducted in a closed cylindrical stainless steel vessel (i.d. 10.22 cm, length 100 cm) with upward flame propagation. The UFL of hydrogen was observed to be inversely proportional to the initial pressure in the range from 1.0 to 0.3 atm and proportional to the initial pressure from 0.3 to 0.05 atm. In contrast, the UFLs of the lower alkanes and ethylene decreased with the initial pressure. The average flame propagation velocities at UFL concentrations of hydrogen, methane, ethane, n-butane, and ethylene in air at reduced pressures were also examined. It was found that the flame propagation velocity of hydrogen was larger than those of the hydrocarbons, increased when the initial pressure decreased from 1.0 to 0.3 atm, and then decreased with further decrease of pressure. Flame propagation velocities at UFL concentrations of the hydrocarbons decreased with the initial pressure. Finally, based on the behavior of the UFLs and flame propagation velocities, the relative risk and hazards of ignition and flame escalation of hydrogen and the light hydrocarbons at subatmospheric pressures were discussed. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132276 Exemplaires
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Titre : Article experimental determination of CO2 solubility in liquid CH4 / N2 mixtures at cryogenic temperatures Type de document : texte imprimé Auteurs : Ting Gao, Auteur ; Taotao Shen, Auteur ; Wensheng Lin, Auteur Année de publication : 2012 Article en page(s) : pp. 9403-9408 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Cryogenics Solubility Carbon dioxide Résumé : Coalbed methane (CBM) is an atypical natural gas that may contain a large amount of nitrogen in addition to methane. When liquefying such CH4/N2 mixtures, knowledge of solid solubility is very important and, in particular, CO2 solubility data are essential for determining the CO2 purification index. Although experimental data for CO2 solubility in pure methane are available for various conditions, such experimental data for CH4/N2 mixtures are rare. In this paper, a solid―liquid equilibrium experimental apparatus using a static-analytic method is described. Data for CO2 solubility in pure liquid methane were obtained and their accuracy was verified by comparison with published values. Solubility of CO2 in CH4/N2 mixtures with nitrogen molar fractions of 10, 30, 50, and 70% were then measured at cryogenic temperatures between -190 and ―150 °C. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132277
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9403-9408[article] Article experimental determination of CO2 solubility in liquid CH4 / N2 mixtures at cryogenic temperatures [texte imprimé] / Ting Gao, Auteur ; Taotao Shen, Auteur ; Wensheng Lin, Auteur . - 2012 . - pp. 9403-9408.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9403-9408
Mots-clés : Cryogenics Solubility Carbon dioxide Résumé : Coalbed methane (CBM) is an atypical natural gas that may contain a large amount of nitrogen in addition to methane. When liquefying such CH4/N2 mixtures, knowledge of solid solubility is very important and, in particular, CO2 solubility data are essential for determining the CO2 purification index. Although experimental data for CO2 solubility in pure methane are available for various conditions, such experimental data for CH4/N2 mixtures are rare. In this paper, a solid―liquid equilibrium experimental apparatus using a static-analytic method is described. Data for CO2 solubility in pure liquid methane were obtained and their accuracy was verified by comparison with published values. Solubility of CO2 in CH4/N2 mixtures with nitrogen molar fractions of 10, 30, 50, and 70% were then measured at cryogenic temperatures between -190 and ―150 °C. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132277 Exemplaires
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Titre : VLL equilibria and critical end points calculation of nitrogen - containing LNG systems : Application of SRK and PC - SAFT equations of state Type de document : texte imprimé Auteurs : Edgar Ramirez-Jiménez, Auteur ; Daimler N. Justo-Garcia, Auteur ; Fernando Garcia-Sanchez, Auteur Année de publication : 2012 Article en page(s) : pp. 9409-9418 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Thermodynamic properties Equations of state LNG Résumé : Two different numerical techniques, applying either the SRK or the PC-SAFT equations of state, were used to predict the multiphase behavior exhibited by the ternary systems nitrogen + methane + ethane, nitrogen + methane + propane, and nitrogen + methane + n-butane. The predictions with both equations of state were compared against experimental data in terms of nitrogen mole fractions of the two liquid phases and it was demonstrated that the agreement is good. Furthermore, a procedure similar to that reported by Gregorowicz and de Loos, in conjunction with the SRK equation of state, was introduced. It was applied to predict the K (L1―L2=V) and LCST (L1=L2―V) critical end points at constant temperature for the systems studied, and demonstrated a reliable and robust performance with good convergence characteristics. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132278
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9409-9418[article] VLL equilibria and critical end points calculation of nitrogen - containing LNG systems : Application of SRK and PC - SAFT equations of state [texte imprimé] / Edgar Ramirez-Jiménez, Auteur ; Daimler N. Justo-Garcia, Auteur ; Fernando Garcia-Sanchez, Auteur . - 2012 . - pp. 9409-9418.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9409-9418
Mots-clés : Thermodynamic properties Equations of state LNG Résumé : Two different numerical techniques, applying either the SRK or the PC-SAFT equations of state, were used to predict the multiphase behavior exhibited by the ternary systems nitrogen + methane + ethane, nitrogen + methane + propane, and nitrogen + methane + n-butane. The predictions with both equations of state were compared against experimental data in terms of nitrogen mole fractions of the two liquid phases and it was demonstrated that the agreement is good. Furthermore, a procedure similar to that reported by Gregorowicz and de Loos, in conjunction with the SRK equation of state, was introduced. It was applied to predict the K (L1―L2=V) and LCST (L1=L2―V) critical end points at constant temperature for the systems studied, and demonstrated a reliable and robust performance with good convergence characteristics. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132278 Exemplaires
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Titre : Analysis of parameter values in the van der waals and platteeuw theory for methane hydrates using monte carlo molecular simulations Type de document : texte imprimé Auteurs : Srikanth Ravipati, Auteur ; Sudeep N. Punnathanam, Auteur Année de publication : 2012 Article en page(s) : pp. 9419–9426 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Methane Hydrates Résumé : The van der Waals and Platteuw (vdWP) theory has been successfully used to model the thermodynamics of gas hydrates. However, earlier studies have shown that this could be due to the presence of a large number of adjustable parameters whose values are obtained through regression with experimental data. To test this assertion, we carry out a systematic and rigorous study of the performance of various models of vdWP theory that have been proposed over the years. The hydrate phase equilibrium data used for this study is obtained from Monte Carlo molecular simulations of methane hydrates. The parameters of the vdWP theory are regressed from this equilibrium data and compared with their true values obtained directly from simulations. This comparison reveals that (i) methane–water interactions beyond the first cage and methane–methane interactions make a significant contribution to the partition function and thus cannot be neglected, (ii) the rigorous Monte Carlo integration should be used to evaluate the Langmuir constant instead of the spherical smoothed cell approximation, (iii) the parameter values describing the methane–water interactions cannot be correctly regressed from the equilibrium data using the vdWP theory in its present form, (iv) the regressed empty hydrate property values closely match their true values irrespective of the level of rigor in the theory, and (v) the flexibility of the water lattice forming the hydrate phase needs to be incorporated in the vdWP theory. Since methane is among the simplest of hydrate forming molecules, the conclusions from this study should also hold true for more complicated hydrate guest molecules. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3004368
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9419–9426[article] Analysis of parameter values in the van der waals and platteeuw theory for methane hydrates using monte carlo molecular simulations [texte imprimé] / Srikanth Ravipati, Auteur ; Sudeep N. Punnathanam, Auteur . - 2012 . - pp. 9419–9426.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9419–9426
Mots-clés : Methane Hydrates Résumé : The van der Waals and Platteuw (vdWP) theory has been successfully used to model the thermodynamics of gas hydrates. However, earlier studies have shown that this could be due to the presence of a large number of adjustable parameters whose values are obtained through regression with experimental data. To test this assertion, we carry out a systematic and rigorous study of the performance of various models of vdWP theory that have been proposed over the years. The hydrate phase equilibrium data used for this study is obtained from Monte Carlo molecular simulations of methane hydrates. The parameters of the vdWP theory are regressed from this equilibrium data and compared with their true values obtained directly from simulations. This comparison reveals that (i) methane–water interactions beyond the first cage and methane–methane interactions make a significant contribution to the partition function and thus cannot be neglected, (ii) the rigorous Monte Carlo integration should be used to evaluate the Langmuir constant instead of the spherical smoothed cell approximation, (iii) the parameter values describing the methane–water interactions cannot be correctly regressed from the equilibrium data using the vdWP theory in its present form, (iv) the regressed empty hydrate property values closely match their true values irrespective of the level of rigor in the theory, and (v) the flexibility of the water lattice forming the hydrate phase needs to be incorporated in the vdWP theory. Since methane is among the simplest of hydrate forming molecules, the conclusions from this study should also hold true for more complicated hydrate guest molecules. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3004368 Exemplaires
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Titre : Analysis of Segregation Data for a Dry Mineral-Based Construction Materials Plant Type de document : texte imprimé Auteurs : Niklas Engblom, Auteur ; Henrik Saxén, Auteur ; Ron Zevenhoven, Auteur Année de publication : 2012 Article en page(s) : pp. 9427-9440 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Construction materials Segregation Résumé : In this work, segregation data for seven commercial products at a dry mineral-based construction materials plant have been analyzed. The segregation manifests itself as an increase of the fines content to unacceptable levels at the end of complete emptying from a surge silo situated upstream of packing. Results for preliminary tests for sifting segregation and fluidization show the difficulty in estimating a priori the segregation patterns observed in practice. Knowledge of the segregation mechanisms occurring with similar materials at silo filling and the discharge flow pattern is utilized to explain the segregation at silo emptying: Accumulation of fine particles at the silo walls during filling and discharge in expanded flow cause fines-rich regions from the vicinity of walls in the lower parts of the silo to be withdrawn last. Large variations in the magnitude of segregation for each product cannot be explained for example by production run size, but are caused by size variations in the silo input, uneven distribution of fines over the heap surface during filling, unpredictable stagnant zones during discharge, and sampling procedure. Segregation at discharge mainly increases with increasing particle size distribution, but the product with the widest size distribution does not segregate the most. The width of the particle size distribution for the products correlates with the mass fraction of fine particles, and inclusion of a special additive (synthetic fibers) in very small proportions is also seen to affect segregation. Therefore, a regression model based on the mass fraction of fines and fibers was employed to organize the products according to the magnitude of segregation. Results for the model show that segregation does not always increase with an increase in the width of the particle size distribution and is negatively affected by inclusion of light and elongated particles (fibers). ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132280
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9427-9440[article] Analysis of Segregation Data for a Dry Mineral-Based Construction Materials Plant [texte imprimé] / Niklas Engblom, Auteur ; Henrik Saxén, Auteur ; Ron Zevenhoven, Auteur . - 2012 . - pp. 9427-9440.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9427-9440
Mots-clés : Construction materials Segregation Résumé : In this work, segregation data for seven commercial products at a dry mineral-based construction materials plant have been analyzed. The segregation manifests itself as an increase of the fines content to unacceptable levels at the end of complete emptying from a surge silo situated upstream of packing. Results for preliminary tests for sifting segregation and fluidization show the difficulty in estimating a priori the segregation patterns observed in practice. Knowledge of the segregation mechanisms occurring with similar materials at silo filling and the discharge flow pattern is utilized to explain the segregation at silo emptying: Accumulation of fine particles at the silo walls during filling and discharge in expanded flow cause fines-rich regions from the vicinity of walls in the lower parts of the silo to be withdrawn last. Large variations in the magnitude of segregation for each product cannot be explained for example by production run size, but are caused by size variations in the silo input, uneven distribution of fines over the heap surface during filling, unpredictable stagnant zones during discharge, and sampling procedure. Segregation at discharge mainly increases with increasing particle size distribution, but the product with the widest size distribution does not segregate the most. The width of the particle size distribution for the products correlates with the mass fraction of fine particles, and inclusion of a special additive (synthetic fibers) in very small proportions is also seen to affect segregation. Therefore, a regression model based on the mass fraction of fines and fibers was employed to organize the products according to the magnitude of segregation. Results for the model show that segregation does not always increase with an increase in the width of the particle size distribution and is negatively affected by inclusion of light and elongated particles (fibers). ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132280 Exemplaires
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Titre : Absorption of hydrophobic volatile organic compounds by a rotating packed bed Type de document : texte imprimé Auteurs : Chia-Ying Chiang, Auteur ; Yi-Ying Liu, Auteur ; Yu-Shao Chen, Auteur Année de publication : 2012 Article en page(s) : pp. 9441-9445 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Packed bed Volatile organic compound Résumé : The high development of industries leads to significant amount of waste hydrophobic volatile organic compounds (VOCs), and these have caused serious environmental concerns. Because of the physical properties of the hydrophobic VOCs, a hydrophobic absorbent is needed in order to make the process more efficient if absorption is considered. However, most of these absorbents have high viscosities which leads to a low mass transfer coefficient. Thus, a cross-flow rotating packed bed (RPB) was evaluated for the feasibility of absorbing the hydrophobic VOCs, xylene, and toluene, by silicon oil, a model hydrophobic absorbent. The result shows that the absorption percentage could be up to 98% within a second contact of liquid and gas. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132281
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9441-9445[article] Absorption of hydrophobic volatile organic compounds by a rotating packed bed [texte imprimé] / Chia-Ying Chiang, Auteur ; Yi-Ying Liu, Auteur ; Yu-Shao Chen, Auteur . - 2012 . - pp. 9441-9445.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9441-9445
Mots-clés : Packed bed Volatile organic compound Résumé : The high development of industries leads to significant amount of waste hydrophobic volatile organic compounds (VOCs), and these have caused serious environmental concerns. Because of the physical properties of the hydrophobic VOCs, a hydrophobic absorbent is needed in order to make the process more efficient if absorption is considered. However, most of these absorbents have high viscosities which leads to a low mass transfer coefficient. Thus, a cross-flow rotating packed bed (RPB) was evaluated for the feasibility of absorbing the hydrophobic VOCs, xylene, and toluene, by silicon oil, a model hydrophobic absorbent. The result shows that the absorption percentage could be up to 98% within a second contact of liquid and gas. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132281 Exemplaires
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