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a - Calcium sulfate hemihydrate preparation from FGD gypsum in recycling mixed salt solutions / Baohong Guan in Chemical engineering journal, Vol. 174 N° 1 (Octobre 2011) 

Public ISBD [article]  in Chemical engineering journal > Vol. 174 N° 1 (Octobre 2011) . - pp. 296–303 Titre : a - Calcium sulfate hemihydrate preparation from FGD gypsum in recycling mixed salt solutions Type de document : texte imprimé Auteurs : Baohong Guan, Auteur ; Yang Li, Auteur ; Hailu Fu, Auteur Année de publication : 2012 Article en page(s) : pp. 296–303 Note générale : Génie chimique Langues : Anglais (eng) Mots-clés : Alpha-calcium  sulfate  hemihydrate  FGD  gypsum  Salt  solution  recycling  Pilot  test Résumé : A pilot scale preparation of α-calcium sulfate hemihydrate (α-HH) from flue gas desulfurization (FGD) gypsum was conducted for the first time in mixed salt solutions under atmospheric pressure. The effects of salt solution recycling on the transition of α-HH from FGD gypsum were investigated by a comparison with that in laboratory scale, focusing on the dehydration rate of FGD gypsum, the crystal morphology, chemical composition and mechanical strength of the products. α-HH could be transformed from FGD gypsum in 3.5–6.0 h even though the salt solution was recycled seven times in laboratory tests and eight times in pilot tests. The product obtained in pilot scale has a purity of 95% and the α-HH crystals are mostly a prismatic morphology, with volume weighted mean diameter (D[3,4]) in the range of 52.9–84.0 μm, 2 h bending strength of 5.6–6.2 MPa and 3 d compressive strength of 15.7–25.3 MPa. The salt solution recycling achieves 56% recovery of salts in pilot scale and puts almost no negative impact on the product quality, which can be one of the best strategies to reduce the production cost. It is very likely that the process of salt solution recycling can be adopted in industry. ISSN : 1385-8947 En ligne : http://www.sciencedirect.com/science/article/pii/S1385894711010916 [article] a - Calcium sulfate hemihydrate preparation from FGD gypsum in recycling mixed salt solutions [texte imprimé] / Baohong Guan, Auteur ; Yang Li, Auteur ; Hailu Fu, Auteur . - 2012 . - pp. 296–303. Génie chimique Langues : Anglais (eng) in Chemical engineering journal > Vol. 174 N° 1 (Octobre 2011) . - pp. 296–303 Mots-clés : Alpha-calcium  sulfate  hemihydrate  FGD  gypsum  Salt  solution  recycling  Pilot  test Résumé : A pilot scale preparation of α-calcium sulfate hemihydrate (α-HH) from flue gas desulfurization (FGD) gypsum was conducted for the first time in mixed salt solutions under atmospheric pressure. The effects of salt solution recycling on the transition of α-HH from FGD gypsum were investigated by a comparison with that in laboratory scale, focusing on the dehydration rate of FGD gypsum, the crystal morphology, chemical composition and mechanical strength of the products. α-HH could be transformed from FGD gypsum in 3.5–6.0 h even though the salt solution was recycled seven times in laboratory tests and eight times in pilot tests. The product obtained in pilot scale has a purity of 95% and the α-HH crystals are mostly a prismatic morphology, with volume weighted mean diameter (D[3,4]) in the range of 52.9–84.0 μm, 2 h bending strength of 5.6–6.2 MPa and 3 d compressive strength of 15.7–25.3 MPa. The salt solution recycling achieves 56% recovery of salts in pilot scale and puts almost no negative impact on the product quality, which can be one of the best strategies to reduce the production cost. It is very likely that the process of salt solution recycling can be adopted in industry. ISSN : 1385-8947 En ligne : http://www.sciencedirect.com/science/article/pii/S1385894711010916

Controllable synthesis, structure, and catalytic activity of highly dispersed Pd catalyst supported on whisker - modified spherical alumina / Yang Li in Industrial & engineering chemistry research, Vol. 51 N° 34 (Août 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 34 (Août 2012) . - pp. 11083-11090 Titre : Controllable synthesis, structure, and catalytic activity of highly dispersed Pd catalyst supported on whisker - modified spherical alumina Type de document : texte imprimé Auteurs : Yang Li, Auteur ; Junting Feng, Auteur ; Yufei He, Auteur Année de publication : 2012 Article en page(s) : pp. 11083-11090 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Catalyst  support  Catalyst  activity Résumé : A new route was introduced to synthesize novel mesoporous spherical alumina supports by in situ growth of alumina whiskers on the surface, and in the pores, of conventional spherical alumina using urea as an OH― donor and a surfactant as a structure-directing agent. BET results indicate that the modified spherical alumina exhibited much higher surface area and more regular mesoporous structure than the unmodified alumina. The whisker-modified spherical aluminas with a flowerlike arrangement of whiskers and higher surface area were then used as support to prepare highly dispersed Pd catalysts. Catalytic performances of the catalysts were studied in the catalytic hydrogenation/oxidation of 2-ethylanthraquinone (EAQ). Compared with a conventional Pd/alumina catalyst, novel Pd/whisker-modined alumina catalysts exhibited much higher Pd dispersion which resulted in more catalytically active sites and therefore significantly higher hydrogenation efficiency. Moreover, shorter diffusion distance reduced the deep hydrogenation of EAQ and consequently achieved higher selectivity and structural stability. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26299432 [article] Controllable synthesis, structure, and catalytic activity of highly dispersed Pd catalyst supported on whisker - modified spherical alumina [texte imprimé] / Yang Li, Auteur ; Junting Feng, Auteur ; Yufei He, Auteur . - 2012 . - pp. 11083-11090. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 34 (Août 2012) . - pp. 11083-11090 Mots-clés : Catalyst  support  Catalyst  activity Résumé : A new route was introduced to synthesize novel mesoporous spherical alumina supports by in situ growth of alumina whiskers on the surface, and in the pores, of conventional spherical alumina using urea as an OH― donor and a surfactant as a structure-directing agent. BET results indicate that the modified spherical alumina exhibited much higher surface area and more regular mesoporous structure than the unmodified alumina. The whisker-modified spherical aluminas with a flowerlike arrangement of whiskers and higher surface area were then used as support to prepare highly dispersed Pd catalysts. Catalytic performances of the catalysts were studied in the catalytic hydrogenation/oxidation of 2-ethylanthraquinone (EAQ). Compared with a conventional Pd/alumina catalyst, novel Pd/whisker-modined alumina catalysts exhibited much higher Pd dispersion which resulted in more catalytically active sites and therefore significantly higher hydrogenation efficiency. Moreover, shorter diffusion distance reduced the deep hydrogenation of EAQ and consequently achieved higher selectivity and structural stability. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26299432

Preparation and characterization of spherical mesoporous CeO2−Al2O3 composites with high thermal stability / Chao Gao in Industrial & engineering chemistry research, Vol. 48 N° 14 (Juillet 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 14 (Juillet 2009) . - pp. 6544–6549 Titre : Preparation and characterization of spherical mesoporous CeO2−Al2O3 composites with high thermal stability Type de document : texte imprimé Auteurs : Chao Gao, Auteur ; Lin, Yan-Jun, Auteur ; Yang Li, Auteur Année de publication : 2009 Article en page(s) : pp. 6544–6549 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Spherical  mesoporous  CeO2−Al2O3  composites  Oil-drop  sol−gel  method  Thermal  stability Résumé : Spherical mesoporous CeO2−Al2O3 composites containing 2, 5, and 8 wt % ceria have been prepared by an oil-drop sol−gel method. A mixed alumina−ceria hydrosol and hexamethylenetetramine solution were mixed together and added dropwise into a hot oil column where spherical gel particles were formed due to surface tension. The spherical gel particles were then aged, washed, dried, and calcined at 600, 960, or 1200 °C. The resulting materials were characterized by X-ray diffraction, nitrogen adsorption−desorption, and temperature-programmed desorption of ammonia. At 1200 °C sintering of pure alumina is severe, whereas the presence of ceria prevents the alumina from sintering, so that the CeO2−Al2O3 composites have much larger BET surface areas than pure alumina. Addition of ceria also leads to an increase in the number of strong acid sites and the total number of acid sites compared with pure alumina. These results show that the spherical mesoporous CeO2−Al2O3 composites prepared in this way are suitable supports for high temperature catalytic processes. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9000508 [article] Preparation and characterization of spherical mesoporous CeO2−Al2O3 composites with high thermal stability [texte imprimé] / Chao Gao, Auteur ; Lin, Yan-Jun, Auteur ; Yang Li, Auteur . - 2009 . - pp. 6544–6549. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 14 (Juillet 2009) . - pp. 6544–6549 Mots-clés : Spherical  mesoporous  CeO2−Al2O3  composites  Oil-drop  sol−gel  method  Thermal  stability Résumé : Spherical mesoporous CeO2−Al2O3 composites containing 2, 5, and 8 wt % ceria have been prepared by an oil-drop sol−gel method. A mixed alumina−ceria hydrosol and hexamethylenetetramine solution were mixed together and added dropwise into a hot oil column where spherical gel particles were formed due to surface tension. The spherical gel particles were then aged, washed, dried, and calcined at 600, 960, or 1200 °C. The resulting materials were characterized by X-ray diffraction, nitrogen adsorption−desorption, and temperature-programmed desorption of ammonia. At 1200 °C sintering of pure alumina is severe, whereas the presence of ceria prevents the alumina from sintering, so that the CeO2−Al2O3 composites have much larger BET surface areas than pure alumina. Addition of ceria also leads to an increase in the number of strong acid sites and the total number of acid sites compared with pure alumina. These results show that the spherical mesoporous CeO2−Al2O3 composites prepared in this way are suitable supports for high temperature catalytic processes. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9000508

A semi-empirical model for condensation heat transfer coefficient of mixed ethanol-water vapors / Yang Li in Journal of heat transfer, Vol. 133 N° 6 (Juin 2011) 

Public ISBD [article]  in Journal of heat transfer > Vol. 133 N° 6 (Juin 2011) . - pp. [061501/1-11] Titre : A semi-empirical model for condensation heat transfer coefficient of mixed ethanol-water vapors Type de document : texte imprimé Auteurs : Yang Li, Auteur ; JunJie Yan, Auteur ; JinShi Wang, Auteur Année de publication : 2011 Article en page(s) : pp. [061501/1-11] Note générale : Physique Langues : Anglais (eng) Mots-clés : Ethanol-water  vapors  Marangoni  condensation  Pseudo-dropwise  Heat  transfer  Theoretical  madel Index. décimale : 536 Chaleur. Thermodynamique Résumé : A semi-empirical model describing the heat transfer characteristics of the pseudo-dropwise condensation of binary vapor on a cooled vertical tube has been formulated. By ignoring the thin film always present on the condensation surface and the intensification of mass transfer caused by the Marangoni effect, the heat transfer characteristics of pseudo-dropwise condensation are tentatively formulated. The model involved an analysis of the diffusion process in the vapor boundary layer along with the heat transfer process through the condensate drops. This model was applied to the condensation of the saturated binary vapor of ethanol and water, and was examined using experimental data at vapor pressure values of 101.33 kPa (provided by Utaka and Wang, 2004, “Characteristic Curves and the Promotion Effect of Ethanol Addition on Steam Condensation Heat Transfer,” Int. J. Heat Mass Transfer, 47, pp. 4507–4516), 84.52 kPa and 47.36 kPa. Calculations using the model show a similar trend to the experimental measurements. With the change of the vapor-to-surface temperature difference, the heat transfer coefficients revealed nonlinear characteristics, with the peak values under all ethanol mass fractions of binary vapor. The heat transfer coefficients increased with decreasing ethanol mass fraction. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...] [article] A semi-empirical model for condensation heat transfer coefficient of mixed ethanol-water vapors [texte imprimé] / Yang Li, Auteur ; JunJie Yan, Auteur ; JinShi Wang, Auteur . - 2011 . - pp. [061501/1-11]. Physique Langues : Anglais (eng) in Journal of heat transfer > Vol. 133 N° 6 (Juin 2011) . - pp. [061501/1-11] Mots-clés : Ethanol-water  vapors  Marangoni  condensation  Pseudo-dropwise  Heat  transfer  Theoretical  madel Index. décimale : 536 Chaleur. Thermodynamique Résumé : A semi-empirical model describing the heat transfer characteristics of the pseudo-dropwise condensation of binary vapor on a cooled vertical tube has been formulated. By ignoring the thin film always present on the condensation surface and the intensification of mass transfer caused by the Marangoni effect, the heat transfer characteristics of pseudo-dropwise condensation are tentatively formulated. The model involved an analysis of the diffusion process in the vapor boundary layer along with the heat transfer process through the condensate drops. This model was applied to the condensation of the saturated binary vapor of ethanol and water, and was examined using experimental data at vapor pressure values of 101.33 kPa (provided by Utaka and Wang, 2004, “Characteristic Curves and the Promotion Effect of Ethanol Addition on Steam Condensation Heat Transfer,” Int. J. Heat Mass Transfer, 47, pp. 4507–4516), 84.52 kPa and 47.36 kPa. Calculations using the model show a similar trend to the experimental measurements. With the change of the vapor-to-surface temperature difference, the heat transfer coefficients revealed nonlinear characteristics, with the peak values under all ethanol mass fractions of binary vapor. The heat transfer coefficients increased with decreasing ethanol mass fraction. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...]

Study on production of CH4 in hydrogen purification with palladium − silver / ceramic composite membranes / Yang Li in Industrial & engineering chemistry research, Vol. 49 N° 9 (Mai 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4377–4382 Titre : Study on production of CH4 in hydrogen purification with palladium − silver / ceramic composite membranes Type de document : texte imprimé Auteurs : Yang Li, Auteur ; BingJia Yao, Auteur ; Tomonori Takahashi, Auteur Année de publication : 2010 Article en page(s) : pp. 4377–4382 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Hydrogen  composite  membranes Résumé : Hydrogen was purified by a series of Pd−Ag/ceramic composite membranes with different Pd−Ag alloy thickness ranging from 2.5 to 15 μm. During the process, methane (CH4) was found to be formed in the permeated gas, which was also reported in related studies. A comprehensive study was carried out to identify the source of CH4 by discussing the influence of membrane defect and feed composition with several gas mixtures as feed gas. It was found that CH4 content in the purified hydrogen increased with the defect degree, and for obtaining 99.9% permeated hydrogen, the helium leakage of the membrane should be less than 0.01 mL min−1 cm−2; whereas no helium flow should be detected, that is, the membranes should be completely defect-free, to achieve 99.999+% hydrogen. Meanwhile, different feed gases were used to discover the reason for production of CH4 during purification; the results revealed that only CO in the feed gas resulted in the formation of CH4 on the permeated side. Finally, on the basis of the above findings, a small amount of Au in the Pd−Ag alloy was added to examine the possibility of preventing CH4 formation, and the preliminary result was satisfactory. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900624v [article] Study on production of CH4 in hydrogen purification with palladium − silver / ceramic composite membranes [texte imprimé] / Yang Li, Auteur ; BingJia Yao, Auteur ; Tomonori Takahashi, Auteur . - 2010 . - pp. 4377–4382. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4377–4382 Mots-clés : Hydrogen  composite  membranes Résumé : Hydrogen was purified by a series of Pd−Ag/ceramic composite membranes with different Pd−Ag alloy thickness ranging from 2.5 to 15 μm. During the process, methane (CH4) was found to be formed in the permeated gas, which was also reported in related studies. A comprehensive study was carried out to identify the source of CH4 by discussing the influence of membrane defect and feed composition with several gas mixtures as feed gas. It was found that CH4 content in the purified hydrogen increased with the defect degree, and for obtaining 99.9% permeated hydrogen, the helium leakage of the membrane should be less than 0.01 mL min−1 cm−2; whereas no helium flow should be detected, that is, the membranes should be completely defect-free, to achieve 99.999+% hydrogen. Meanwhile, different feed gases were used to discover the reason for production of CH4 during purification; the results revealed that only CO in the feed gas resulted in the formation of CH4 on the permeated side. Finally, on the basis of the above findings, a small amount of Au in the Pd−Ag alloy was added to examine the possibility of preventing CH4 formation, and the preliminary result was satisfactory. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900624v