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Clathrate hydrate formation from cyclopentane-in-water emulsions / Masahiro Nakajima ; Ryo Ohmura ; Yasuhiko H. Mori in Industrial & engineering chemistry research, Vol. 47 n°22 (Novembre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°22 (Novembre 2008) . - p. 8933–8939 Titre : Clathrate hydrate formation from cyclopentane-in-water emulsions Type de document : texte imprimé Auteurs : Masahiro Nakajima, Auteur ; Ryo Ohmura, Auteur ; Yasuhiko H. Mori, Auteur Année de publication : 2008 Article en page(s) : p. 8933–8939 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Clathrate  Hydrate Résumé : This paper reports the experimental examinations of hydrate-forming cyclopentane-in-water emulsions as potential thermal energy storage media for air-conditioning systems. It was demonstrated that an adequately compounded cyclopentane/water/surfactant mixture formed a stable emulsion with the aid of continuous agitation and, through its cooling to ∼2 °C, turned into a bulky mass of granular hydrate crystals. The behavior of the hydrate formation was investigated by varying the amount and composition of the surfactant (or surfactant mixture) in the sample cyclopentane/water/surfactant mixture from run to run in order to determine the appropriate preparation of the mixture for efficient hydrate formation. Also performed were measurements of the effective heat of dissociation for the granular hydrate products obtained in the above hydrate-forming experiments. The measurements showed that the effective heat of dissociation can be as high as ∼93% of the intrinsic heat of dissociation of cyclopentane hydrate crystals, thereby indicating a sufficient potential of the cyclopentane-in-water emulsions as thermal energy storage media. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800949k [article] Clathrate hydrate formation from cyclopentane-in-water emulsions [texte imprimé] / Masahiro Nakajima, Auteur ; Ryo Ohmura, Auteur ; Yasuhiko H. Mori, Auteur . - 2008 . - p. 8933–8939. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°22 (Novembre 2008) . - p. 8933–8939 Mots-clés : Clathrate  Hydrate Résumé : This paper reports the experimental examinations of hydrate-forming cyclopentane-in-water emulsions as potential thermal energy storage media for air-conditioning systems. It was demonstrated that an adequately compounded cyclopentane/water/surfactant mixture formed a stable emulsion with the aid of continuous agitation and, through its cooling to ∼2 °C, turned into a bulky mass of granular hydrate crystals. The behavior of the hydrate formation was investigated by varying the amount and composition of the surfactant (or surfactant mixture) in the sample cyclopentane/water/surfactant mixture from run to run in order to determine the appropriate preparation of the mixture for efficient hydrate formation. Also performed were measurements of the effective heat of dissociation for the granular hydrate products obtained in the above hydrate-forming experiments. The measurements showed that the effective heat of dissociation can be as high as ∼93% of the intrinsic heat of dissociation of cyclopentane hydrate crystals, thereby indicating a sufficient potential of the cyclopentane-in-water emulsions as thermal energy storage media. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800949k

Correlation of hydrate-film growth rate at the guest/liquid-water interface to mass transfer resistance / Kota Saito in Industrial & engineering chemistry research, Vol. 49 N° 15 (Août 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 15 (Août 2010) . - pp 7102–7103 Titre : Correlation of hydrate-film growth rate at the guest/liquid-water interface to mass transfer resistance Type de document : texte imprimé Auteurs : Kota Saito, Auteur ; Amadeu K. Sum, Auteur ; Ryo Ohmura, Auteur Année de publication : 2010 Article en page(s) : pp 7102–7103 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Correlation  hydrate  film  Mass  transfer  Heat  transfer. Résumé : The correlation of hydrate-film growth rate at the guest/liquid-water interface to mass transfer limitations is considered. Most of the hydrate-film growth rate data from the literature are compiled based on the system subcooling (ΔT), suggesting predominant heat transfer limitations. In this communication, we investigate how existing data on hydrate-film growth is better correlated to solubility differences of the guest species in equilibrium with bulk fluid and hydrate. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1000696 [article] Correlation of hydrate-film growth rate at the guest/liquid-water interface to mass transfer resistance [texte imprimé] / Kota Saito, Auteur ; Amadeu K. Sum, Auteur ; Ryo Ohmura, Auteur . - 2010 . - pp 7102–7103. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 15 (Août 2010) . - pp 7102–7103 Mots-clés : Correlation  hydrate  film  Mass  transfer  Heat  transfer. Résumé : The correlation of hydrate-film growth rate at the guest/liquid-water interface to mass transfer limitations is considered. Most of the hydrate-film growth rate data from the literature are compiled based on the system subcooling (ΔT), suggesting predominant heat transfer limitations. In this communication, we investigate how existing data on hydrate-film growth is better correlated to solubility differences of the guest species in equilibrium with bulk fluid and hydrate. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1000696

Crystal growth of clathrate hydrate at the interface between seawater and hydrophobic - guest liquid / Masatoshi Kishimoto in Industrial & engineering chemistry research, Vol. 51 N° 14 (Avril 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 14 (Avril 2012) . - pp. 5224-5229 Titre : Crystal growth of clathrate hydrate at the interface between seawater and hydrophobic - guest liquid : Effect of elevated salt concentration Type de document : texte imprimé Auteurs : Masatoshi Kishimoto, Auteur ; Satoshi Iijima, Auteur ; Ryo Ohmura, Auteur Année de publication : 2012 Article en page(s) : pp. 5224-5229 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Seawater  Clathrate  Crystal  growth Résumé : This paper reports the visual observations of the clathrate hydrate crystal growth and morphology at the interface of aqueous NaCl solutions and a guest-substance liquid. The hydrate crystal growth was visually characterized in the systems of a wide range of NaCl concentrations from 0.035 to 0.264 in mass fraction. The mass fraction 0.035 was corresponding to that of ordinary seawater, and the salt concentration tested was extended up to the saturation level, i.e., 0.264. Cyclopentane was used as the guest substance. Formation and growth of hydrate crystals at the cyclopentane-NaCl solution interface were observed. We visually analyzed the individual hydrate crystals and classified the morphology of the crystals according to ΔTsub at atmospheric pressure. It was found that the size of the individual hydrate crystals decreased with increasing ΔTsub. The results showed that the morphology of the individual hydrate crystals in any NaCl concentration is roughly similar at a given ΔTsub. We also measured the lateral growth rates of the hydrate-film propagation. The hydrate film growth rate decreased with decreasing ΔTsub in any of the systems and decreased with increasing concentration of NaCl at a given ΔTsub. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25783431 [article] Crystal growth of clathrate hydrate at the interface between seawater and hydrophobic - guest liquid : Effect of elevated salt concentration [texte imprimé] / Masatoshi Kishimoto, Auteur ; Satoshi Iijima, Auteur ; Ryo Ohmura, Auteur . - 2012 . - pp. 5224-5229. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 14 (Avril 2012) . - pp. 5224-5229 Mots-clés : Seawater  Clathrate  Crystal  growth Résumé : This paper reports the visual observations of the clathrate hydrate crystal growth and morphology at the interface of aqueous NaCl solutions and a guest-substance liquid. The hydrate crystal growth was visually characterized in the systems of a wide range of NaCl concentrations from 0.035 to 0.264 in mass fraction. The mass fraction 0.035 was corresponding to that of ordinary seawater, and the salt concentration tested was extended up to the saturation level, i.e., 0.264. Cyclopentane was used as the guest substance. Formation and growth of hydrate crystals at the cyclopentane-NaCl solution interface were observed. We visually analyzed the individual hydrate crystals and classified the morphology of the crystals according to ΔTsub at atmospheric pressure. It was found that the size of the individual hydrate crystals decreased with increasing ΔTsub. The results showed that the morphology of the individual hydrate crystals in any NaCl concentration is roughly similar at a given ΔTsub. We also measured the lateral growth rates of the hydrate-film propagation. The hydrate film growth rate decreased with decreasing ΔTsub in any of the systems and decreased with increasing concentration of NaCl at a given ΔTsub. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25783431