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Effects of design and operating parameters on CO2 absorption in microchannel contactors / Haining Niu in Industrial & engineering chemistry research, Vol. 48 N° 18 (Septembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 18 (Septembre 2009) . - pp. 8629–8634 Titre : Effects of design and operating parameters on CO2 absorption in microchannel contactors Type de document : texte imprimé Auteurs : Haining Niu, Auteur ; Liwei Pan, Auteur ; Hongjiu Su, Auteur Année de publication : 2010 Article en page(s) : pp. 8629–8634 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Microchannel  contactors  CO2  absorption Résumé : This study provides experimental data on the performance of microchannel contactors for CO2 absorption. An aqueous solution of piperazine (PZ) activated N-methyldiethanolamine (MDEA) and a mixture of CO2/N2 were selected as the working fluids. Three different sizes of microchannels, with hydraulic diameters of 0.5, 1, and 2 mm and the same length of 180 mm, served as the contactors. With a decrease in the hydraulic diameter the larger surface to volume ratio can be achieved. The mass transfer rates increased considerably, and the size effect of mass transfer was observed. Various operating parameters, including the activator, the temperature of gas and liquid flow, the inlet CO2 molar fraction, the superficial gas and liquid velocities, and the operating pressure were also evaluated. The results obtained illustrated a great potential of microchannel contactors when they were applied to the separation of CO2. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8018966 [article] Effects of design and operating parameters on CO2 absorption in microchannel contactors [texte imprimé] / Haining Niu, Auteur ; Liwei Pan, Auteur ; Hongjiu Su, Auteur . - 2010 . - pp. 8629–8634. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 18 (Septembre 2009) . - pp. 8629–8634 Mots-clés : Microchannel  contactors  CO2  absorption Résumé : This study provides experimental data on the performance of microchannel contactors for CO2 absorption. An aqueous solution of piperazine (PZ) activated N-methyldiethanolamine (MDEA) and a mixture of CO2/N2 were selected as the working fluids. Three different sizes of microchannels, with hydraulic diameters of 0.5, 1, and 2 mm and the same length of 180 mm, served as the contactors. With a decrease in the hydraulic diameter the larger surface to volume ratio can be achieved. The mass transfer rates increased considerably, and the size effect of mass transfer was observed. Various operating parameters, including the activator, the temperature of gas and liquid flow, the inlet CO2 molar fraction, the superficial gas and liquid velocities, and the operating pressure were also evaluated. The results obtained illustrated a great potential of microchannel contactors when they were applied to the separation of CO2. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8018966

Flow pattern, pressure drop, and mass transfer in a gas-liquid concurrent two-phase flow microchannel reactor / Haining Niu in Industrial & engineering chemistry research, Vol. 48 N°3 (Février 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1621–1628 Titre : Flow pattern, pressure drop, and mass transfer in a gas-liquid concurrent two-phase flow microchannel reactor Type de document : texte imprimé Auteurs : Haining Niu, Auteur ; Liwei Pan, Auteur ; Hongjiu Su, Auteur Année de publication : 2009 Article en page(s) : p. 1621–1628 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Gas-liquid  --  pressure  drop  Gas-liquid  --  mass  transfer  Gas-liquid  --  flow  pattern Résumé : Flow pattern, pressure drop, and mass transfer characteristics have been studied for the gas-liquid two-phase flow in a 1.0 mm inner diameter circular microchannel reactor. A mixture of CO2, N2, and polyethylene glycol dimethyl ether was used to represent the gas and liquid phases, respectively. Bubbly, slug, churn, and slug-annular flow patterns were observed in the present work. A flow pattern map using superficial gas and liquid velocities as coordinates has been developed and compared to the existing flow pattern maps for ∼1 mm diameter channels. The data obtained for the pressure drop of the two-phase flow were analyzed and compared with the homogeneous model and the separate flow model to assess their predictive capabilities. The liquid side volumetric mass transfer coefficient increased with an increase of the superficial gas and liquid velocities, and the influences of the superficial gas and liquid velocities on it were demonstrated. The liquid side mass transfer coefficient, which was as high as 3.34 s-1, was 1 or 2 orders of magnitude higher than the traditional industrial gas−liquid contactors. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801095a [article] Flow pattern, pressure drop, and mass transfer in a gas-liquid concurrent two-phase flow microchannel reactor [texte imprimé] / Haining Niu, Auteur ; Liwei Pan, Auteur ; Hongjiu Su, Auteur . - 2009 . - p. 1621–1628. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°3 (Février 2009) . - p. 1621–1628 Mots-clés : Gas-liquid  --  pressure  drop  Gas-liquid  --  mass  transfer  Gas-liquid  --  flow  pattern Résumé : Flow pattern, pressure drop, and mass transfer characteristics have been studied for the gas-liquid two-phase flow in a 1.0 mm inner diameter circular microchannel reactor. A mixture of CO2, N2, and polyethylene glycol dimethyl ether was used to represent the gas and liquid phases, respectively. Bubbly, slug, churn, and slug-annular flow patterns were observed in the present work. A flow pattern map using superficial gas and liquid velocities as coordinates has been developed and compared to the existing flow pattern maps for ∼1 mm diameter channels. The data obtained for the pressure drop of the two-phase flow were analyzed and compared with the homogeneous model and the separate flow model to assess their predictive capabilities. The liquid side volumetric mass transfer coefficient increased with an increase of the superficial gas and liquid velocities, and the influences of the superficial gas and liquid velocities on it were demonstrated. The liquid side mass transfer coefficient, which was as high as 3.34 s-1, was 1 or 2 orders of magnitude higher than the traditional industrial gas−liquid contactors. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801095a

The Characteristics of Pressure Drop in Microchannels / Hongjiu Su in Industrial & engineering chemistry research, Vol. 49 N° 8 (Avril 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 8 (Avril 2010) . - pp. 3830–3839 Titre : The Characteristics of Pressure Drop in Microchannels Type de document : texte imprimé Auteurs : Hongjiu Su, Auteur ; Haining Niu, Auteur ; Liwei Pan, Auteur Année de publication : 2010 Article en page(s) : pp. 3830–3839 Langues : Anglais (eng) Mots-clés : Microchannels Résumé : The characteristics of the pressure drop of fluid were investigated in three different kinds of stainless steel microchannels with diameter of 0.56, 1.00, and 1.80 mm based on the absorption in the microchannels. For the single-phase flow pressure drop, nitrogen being used as the test fluid, it was found that the transition between the laminar and turbulent flow occurred at the Reynolds number of about 2000, which was different from some previous reports in which the early flow transition was observed in microchannels. For the two-phase flow pressure drop, an industrial chemical absorbent (40 wt % MDEA solution) and nitrogen being taken as the working fluid, it was found that the existing correlations including the homogeneous flow model and separated flow model failed to predict the experimental results because of the special operating condition in which the ratio of volumetric flow rate of gas to liquid phase ranged from 100 to 3400. A new correlation to predict the two-phase flow pressure drop was developed in the form of the Lockhart−Martinelli type which considered the effect of surface tension, gas phase inertial force, Reynolds number of liquid phase, and the Martinelli parameter. The predicted data with new correlation showed good agreement with the experimental results. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9015045 [article] The Characteristics of Pressure Drop in Microchannels [texte imprimé] / Hongjiu Su, Auteur ; Haining Niu, Auteur ; Liwei Pan, Auteur . - 2010 . - pp. 3830–3839. Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 8 (Avril 2010) . - pp. 3830–3839 Mots-clés : Microchannels Résumé : The characteristics of the pressure drop of fluid were investigated in three different kinds of stainless steel microchannels with diameter of 0.56, 1.00, and 1.80 mm based on the absorption in the microchannels. For the single-phase flow pressure drop, nitrogen being used as the test fluid, it was found that the transition between the laminar and turbulent flow occurred at the Reynolds number of about 2000, which was different from some previous reports in which the early flow transition was observed in microchannels. For the two-phase flow pressure drop, an industrial chemical absorbent (40 wt % MDEA solution) and nitrogen being taken as the working fluid, it was found that the existing correlations including the homogeneous flow model and separated flow model failed to predict the experimental results because of the special operating condition in which the ratio of volumetric flow rate of gas to liquid phase ranged from 100 to 3400. A new correlation to predict the two-phase flow pressure drop was developed in the form of the Lockhart−Martinelli type which considered the effect of surface tension, gas phase inertial force, Reynolds number of liquid phase, and the Martinelli parameter. The predicted data with new correlation showed good agreement with the experimental results. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9015045