Documents disponibles écrits par cet auteur

Bubble size distribution for a bubble column reactor undergoing forced oscillations / Y. G. Waghmare in Industrial & engineering chemistry research, Vol. 48 N°4 (Février 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1786–1796 Titre : Bubble size distribution for a bubble column reactor undergoing forced oscillations Type de document : texte imprimé Auteurs : Y. G. Waghmare, Auteur ; C. A. Dorao, Auteur ; H. A. Jakobsen, Auteur Année de publication : 2009 Article en page(s) : pp. 1786–1796 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Oscillations  Bubble  size  distribution  Air-water  system  Breakage  models Résumé : It has recently been shown that low amplitude (0.5−2.5 mm) oscillations at low frequencies (10−25 Hz) can be used to improve bubble column performance. Here, we report the study of bubble size distribution (BSD) in an oscillating bubble column for the air−water system. BSD was measured at different heights in the column, and the effects of various operating parameters such as frequency, amplitude, and gas flow rate were studied. Sauter mean diameter was calculated from BSD data, and it was correlated as a function of power input per unit mass using the Hinze formula. Population balance modeling simulations were performed. Two different breakage models (Martinez−Bazan and Luo−Svendsen) were considered which differ fundamentally in the constitution of the models and as a result predict opposite shapes of daughter size distribution curves. Simulation results were compared against experimental data, and both the models gave good comparisons with the measured Sauter mean bubble diameters. The predictions obtained from the simulation for BSD using the Martinez−Bazan model were in quantitative agreement with the experimental observations suggesting vibrations produce nearly equal size bubble breakage. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801375h [article] Bubble size distribution for a bubble column reactor undergoing forced oscillations [texte imprimé] / Y. G. Waghmare, Auteur ; C. A. Dorao, Auteur ; H. A. Jakobsen, Auteur . - 2009 . - pp. 1786–1796. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1786–1796 Mots-clés : Oscillations  Bubble  size  distribution  Air-water  system  Breakage  models Résumé : It has recently been shown that low amplitude (0.5−2.5 mm) oscillations at low frequencies (10−25 Hz) can be used to improve bubble column performance. Here, we report the study of bubble size distribution (BSD) in an oscillating bubble column for the air−water system. BSD was measured at different heights in the column, and the effects of various operating parameters such as frequency, amplitude, and gas flow rate were studied. Sauter mean diameter was calculated from BSD data, and it was correlated as a function of power input per unit mass using the Hinze formula. Population balance modeling simulations were performed. Two different breakage models (Martinez−Bazan and Luo−Svendsen) were considered which differ fundamentally in the constitution of the models and as a result predict opposite shapes of daughter size distribution curves. Simulation results were compared against experimental data, and both the models gave good comparisons with the measured Sauter mean bubble diameters. The predictions obtained from the simulation for BSD using the Martinez−Bazan model were in quantitative agreement with the experimental observations suggesting vibrations produce nearly equal size bubble breakage. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801375h

Dynamic simulation of Ledinegg instability / L.C. Ruspini in Journal of natural gas science and engineering, Vol. 2 N° 5 (Novembre 2010) 

Public ISBD [article]  in Journal of natural gas science and engineering > Vol. 2 N° 5 (Novembre 2010) . - pp. 211–216 Titre : Dynamic simulation of Ledinegg instability Type de document : texte imprimé Auteurs : L.C. Ruspini, Auteur ; C. A. Dorao, Auteur ; M. Fernandino, Auteur Année de publication : 2012 Article en page(s) : pp. 211–216 Note générale : Génie Chimique Langues : Anglais (eng) Mots-clés : Ledinegg  instability  Transient  simulation  Two-phase  flows  Thermal-hydraulic  instabilities  Adaptive  method Résumé : Ledinegg flow excursion could produce severe damage in thermal-hydraulic components due to fast changes in the main thermodynamic variables. In this work, we study this phenomenon simulating the transient behavior of the system during these excursive transitions. We also study how the dynamic delays modify the pressure drop vs. flow characteristic curve. Numerical aspects related to the application of an adaptive high-order method to the resolution of these complex thermal-hydraulic problems are discussed. ISSN : 1875-5100 En ligne : http://www.sciencedirect.com/science/article/pii/S1875510010000661 [article] Dynamic simulation of Ledinegg instability [texte imprimé] / L.C. Ruspini, Auteur ; C. A. Dorao, Auteur ; M. Fernandino, Auteur . - 2012 . - pp. 211–216. Génie Chimique Langues : Anglais (eng) in Journal of natural gas science and engineering > Vol. 2 N° 5 (Novembre 2010) . - pp. 211–216 Mots-clés : Ledinegg  instability  Transient  simulation  Two-phase  flows  Thermal-hydraulic  instabilities  Adaptive  method Résumé : Ledinegg flow excursion could produce severe damage in thermal-hydraulic components due to fast changes in the main thermodynamic variables. In this work, we study this phenomenon simulating the transient behavior of the system during these excursive transitions. We also study how the dynamic delays modify the pressure drop vs. flow characteristic curve. Numerical aspects related to the application of an adaptive high-order method to the resolution of these complex thermal-hydraulic problems are discussed. ISSN : 1875-5100 En ligne : http://www.sciencedirect.com/science/article/pii/S1875510010000661

Influence of the plot area in an economical analysis for selecting small scale LNG technologies for remote gas production / L. Castillo in Journal of natural gas science and engineering, Vol. 2 N° 6 (Décembre 2010) 

Public ISBD [article]  in Journal of natural gas science and engineering > Vol. 2 N° 6 (Décembre 2010) . - pp. 302–309 Titre : Influence of the plot area in an economical analysis for selecting small scale LNG technologies for remote gas production Type de document : texte imprimé Auteurs : L. Castillo, Auteur ; C. A. Dorao, Auteur Année de publication : 2012 Article en page(s) : pp. 302–309 Note générale : Génie Chimique Langues : Anglais (eng) Mots-clés : Small  scale  LNG  Remote  gas  fields  Selection  criterion  Offshore  Plot  area Résumé : The future commercial exploitation of remote, small and less accessible gas fields might require the development of new technologies. In particular, LNG technologies are a possible solution for the exploitation of such gas reserves. However, the economy of scale is not applicable and constraint in the offshore installation and harsh environmental conditions require compact and efficient solutions. During the last decade several liquefaction technologies are available for small and medium LNG plants. Even though, the comparison between these technologies from an economical point of view is limited to the efficiency of the process and some qualitative parameters. In this work two groups of LNG technologies are analyzed for a given development scenario. The most important aspect in this work is that the cost related to the offshore installation is included as a component of the CAPEX of the project. The plot area required for each technology plays a significant role in the final comparison and this parameter should not be neglected in the economical analysis of future offshore LNG plants. ISSN : 1875-5100 En ligne : http://www.sciencedirect.com/science/article/pii/S187551001000051X [article] Influence of the plot area in an economical analysis for selecting small scale LNG technologies for remote gas production [texte imprimé] / L. Castillo, Auteur ; C. A. Dorao, Auteur . - 2012 . - pp. 302–309. Génie Chimique Langues : Anglais (eng) in Journal of natural gas science and engineering > Vol. 2 N° 6 (Décembre 2010) . - pp. 302–309 Mots-clés : Small  scale  LNG  Remote  gas  fields  Selection  criterion  Offshore  Plot  area Résumé : The future commercial exploitation of remote, small and less accessible gas fields might require the development of new technologies. In particular, LNG technologies are a possible solution for the exploitation of such gas reserves. However, the economy of scale is not applicable and constraint in the offshore installation and harsh environmental conditions require compact and efficient solutions. During the last decade several liquefaction technologies are available for small and medium LNG plants. Even though, the comparison between these technologies from an economical point of view is limited to the efficiency of the process and some qualitative parameters. In this work two groups of LNG technologies are analyzed for a given development scenario. The most important aspect in this work is that the cost related to the offshore installation is included as a component of the CAPEX of the project. The plot area required for each technology plays a significant role in the final comparison and this parameter should not be neglected in the economical analysis of future offshore LNG plants. ISSN : 1875-5100 En ligne : http://www.sciencedirect.com/science/article/pii/S187551001000051X

Solution of a Cattaneo-Maxwell diffusion model using a Spectral element least-squares method / A. R. Carella in Journal of natural gas science and engineering, Vol. 2 N° 5 (Novembre 2010) 

Public ISBD [article]  in Journal of natural gas science and engineering > Vol. 2 N° 5 (Novembre 2010) . - pp. 253–258 Titre : Solution of a Cattaneo-Maxwell diffusion model using a Spectral element least-squares method Type de document : texte imprimé Auteurs : A. R. Carella, Auteur ; C. A. Dorao, Auteur Année de publication : 2012 Article en page(s) : pp. 253–258 Note générale : Génie Chimique Langues : Anglais (eng) Mots-clés : Hyperbolic  diffusion  equation  Finite  element  Cattaneo-Maxwell  Least  squares  method Résumé : Fluidized bed reactors are widely used in gas processing facilities due to their superior heat and mass transfer characteristics. Reaction rates in these reactors depend on the diffusion of species into the catalytic particles. A more accurate description of diffusion than Fick’s law provides is required for the optimization of the design of these reactors. In this work, a Least Squares Finite Element framework was implemented in order to solve the evolution of the concentration profile predicted by Cattaneo-Maxwell’s law inside a catalytic pellet. Fick’s and Cattaneo-Maxwell’s models were compared, being the obtained predictions significantly different for time scales similar to the relaxation time but converging asymptotically for larger time scales. Time-marching and full-domain numerical approaches were compared. The convenience of the time-marching approach was verified, since this approach yields the same accuracy with less computational cost. ISSN : 1875-5100 En ligne : http://www.sciencedirect.com/science/article/pii/S1875510010000648 [article] Solution of a Cattaneo-Maxwell diffusion model using a Spectral element least-squares method [texte imprimé] / A. R. Carella, Auteur ; C. A. Dorao, Auteur . - 2012 . - pp. 253–258. Génie Chimique Langues : Anglais (eng) in Journal of natural gas science and engineering > Vol. 2 N° 5 (Novembre 2010) . - pp. 253–258 Mots-clés : Hyperbolic  diffusion  equation  Finite  element  Cattaneo-Maxwell  Least  squares  method Résumé : Fluidized bed reactors are widely used in gas processing facilities due to their superior heat and mass transfer characteristics. Reaction rates in these reactors depend on the diffusion of species into the catalytic particles. A more accurate description of diffusion than Fick’s law provides is required for the optimization of the design of these reactors. In this work, a Least Squares Finite Element framework was implemented in order to solve the evolution of the concentration profile predicted by Cattaneo-Maxwell’s law inside a catalytic pellet. Fick’s and Cattaneo-Maxwell’s models were compared, being the obtained predictions significantly different for time scales similar to the relaxation time but converging asymptotically for larger time scales. Time-marching and full-domain numerical approaches were compared. The convenience of the time-marching approach was verified, since this approach yields the same accuracy with less computational cost. ISSN : 1875-5100 En ligne : http://www.sciencedirect.com/science/article/pii/S1875510010000648