Documents disponibles écrits par cet auteur

Bubble characterization in a fluidized bed with vertical tubes / Martin Rudisuli in Industrial & engineering chemistry research, Vol. 51 N° 12 (Mars 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 12 (Mars 2012) . - pp. 4748–4758 Titre : Bubble characterization in a fluidized bed with vertical tubes Type de document : texte imprimé Auteurs : Martin Rudisuli, Auteur ; Tilman J. Schildhauer, Auteur ; Serge M. A. Biollaz, Auteur Année de publication : 2012 Article en page(s) : pp. 4748–4758 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Fluidized  beds  Heat  exchanger Résumé : Vertical tubes are commonly used in industrial fluidized beds as heat exchanger tubes. In this study, the influence of vertical tube banks on the axial bubble growth in a 145-mm inner diameter (ID) fluidized bed with Geldart B particles is experimentally investigated by means of pressure fluctuation measurement (PFM) and optical probing (OP). The employed tube bank configurations differ in their tube-to-tube spacing, tube diameter, and tube arrangement (square versus triangular). PFM and OP show that immersed vertical tube banks, irrespective of their configuration, significantly reduce the axial bubble growth. The bubble size reduction is even more significant for higher gas velocities (u0/umf > 4.6, where u0 is the superficial gas velocity and umf is the minimum fluidization velocity) as well as if the tube-to-tube spacing is narrow and the tube diameter is small. The tube arrangement (square versus triangular), in turn, does not show any significant differences. Depending on the gas velocity, the ratio of the bubble diameter to the tube diameter and the tube-to-tube spacing is changed. This change invokes a different bubble flow pattern between the vertical tubes and different bubble growth mechanism, which defines the effectiveness of vertical tubes to delay slugging and makes the fluidization smoother. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2022306 [article] Bubble characterization in a fluidized bed with vertical tubes [texte imprimé] / Martin Rudisuli, Auteur ; Tilman J. Schildhauer, Auteur ; Serge M. A. Biollaz, Auteur . - 2012 . - pp. 4748–4758. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 12 (Mars 2012) . - pp. 4748–4758 Mots-clés : Fluidized  beds  Heat  exchanger Résumé : Vertical tubes are commonly used in industrial fluidized beds as heat exchanger tubes. In this study, the influence of vertical tube banks on the axial bubble growth in a 145-mm inner diameter (ID) fluidized bed with Geldart B particles is experimentally investigated by means of pressure fluctuation measurement (PFM) and optical probing (OP). The employed tube bank configurations differ in their tube-to-tube spacing, tube diameter, and tube arrangement (square versus triangular). PFM and OP show that immersed vertical tube banks, irrespective of their configuration, significantly reduce the axial bubble growth. The bubble size reduction is even more significant for higher gas velocities (u0/umf > 4.6, where u0 is the superficial gas velocity and umf is the minimum fluidization velocity) as well as if the tube-to-tube spacing is narrow and the tube diameter is small. The tube arrangement (square versus triangular), in turn, does not show any significant differences. Depending on the gas velocity, the ratio of the bubble diameter to the tube diameter and the tube-to-tube spacing is changed. This change invokes a different bubble flow pattern between the vertical tubes and different bubble growth mechanism, which defines the effectiveness of vertical tubes to delay slugging and makes the fluidization smoother. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2022306

Fluidized bed methanation of wood-derived producer gas for the production of synthetic natural gas / Martin C. Seemann 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 7034–7038 Titre : Fluidized bed methanation of wood-derived producer gas for the production of synthetic natural gas Type de document : texte imprimé Auteurs : Martin C. Seemann, Auteur ; Tilman J. Schildhauer, Auteur ; Serge M. A. Biollaz, Auteur Année de publication : 2010 Article en page(s) : pp 7034–7038 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Fluidized  bed  Wood  derived  Natural  gas. Résumé : For proving the concept of SNG production from wood gasification derived producer gas under real conditions, a mobile bench-scale fluidized bed reactor setup was fed with producer gas of the Fast Internally Circulating Bed (FICFB) wood gasifier in Gssing, Austria. In long-term experiments, it could be shown that the fluidized methanation catalyst allows for constantly high CO-conversion (about 98%) and CH4 concentration (about 40%) in the outlet. A similar experiment was conducted in a bench-scale reactor that allows for the measurement of axial gas phase concentration profiles by means of a movable sampling tube. It could be shown that under the chosen operation conditions, all three important reactions (methanation, water gas shift, and reforming of olefins) take place very rapidly in a region close to the reactor inlet. In the rest of the bed, the reaction of reactants transferred from the bubbles to the catalyst containing dense phase of the fluidized bed reactor is dominant. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100510m [article] Fluidized bed methanation of wood-derived producer gas for the production of synthetic natural gas [texte imprimé] / Martin C. Seemann, Auteur ; Tilman J. Schildhauer, Auteur ; Serge M. A. Biollaz, Auteur . - 2010 . - pp 7034–7038. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 15 (Août 2010) . - pp 7034–7038 Mots-clés : Fluidized  bed  Wood  derived  Natural  gas. Résumé : For proving the concept of SNG production from wood gasification derived producer gas under real conditions, a mobile bench-scale fluidized bed reactor setup was fed with producer gas of the Fast Internally Circulating Bed (FICFB) wood gasifier in Gssing, Austria. In long-term experiments, it could be shown that the fluidized methanation catalyst allows for constantly high CO-conversion (about 98%) and CH4 concentration (about 40%) in the outlet. A similar experiment was conducted in a bench-scale reactor that allows for the measurement of axial gas phase concentration profiles by means of a movable sampling tube. It could be shown that under the chosen operation conditions, all three important reactions (methanation, water gas shift, and reforming of olefins) take place very rapidly in a region close to the reactor inlet. In the rest of the bed, the reaction of reactants transferred from the bubbles to the catalyst containing dense phase of the fluidized bed reactor is dominant. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100510m

Radial bubble distribution in a fluidized bed with vertical tubes / Martin Rüdisüli in Industrial & engineering chemistry research, Vol. 51 N° 42 (Octobre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 42 (Octobre 2012) . - pp. 13815-13824 Titre : Radial bubble distribution in a fluidized bed with vertical tubes Type de document : texte imprimé Auteurs : Martin Rüdisüli, Auteur ; Tilman J. Schildhauer, Auteur ; Serge M. A. Biollaz, Auteur Année de publication : 2012 Article en page(s) : pp. 13815-13824 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Vertical  tube  Fluidized  bed  Fluidization  Bubble Résumé : The radial distribution of bubble characteristics such as the bubble frequency, the bubble size, and the bubble rise velocity, is a key to better understanding the flow patterns of gas (and solids) in bubbling fluidized beds. Therefore, the radial distribution of bubble characteristics is investigated in a fluidized bed with vertical tubes by means of optical probes. Measurements are taken for Geldart B particles at two bed heights, three gas velocities, and three vertical tube bank configurations. While the bubble frequency shows a strong dependence on the radial position in the bed and the orientation of the vertical tubes, the bubble size and the bubble rise velocity, in particular in the lower portions of the bed, are more constant. Typical bubble pathways are shown to move from the column wall to the center axis of the bed with increased bed height. Therefore, in order to have a representative mean bubble size and mean bubble rise velocity, which accounts for the whole cross-section of the bed, an area-number weighted mean is introduced. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26508205 [article] Radial bubble distribution in a fluidized bed with vertical tubes [texte imprimé] / Martin Rüdisüli, Auteur ; Tilman J. Schildhauer, Auteur ; Serge M. A. Biollaz, Auteur . - 2012 . - pp. 13815-13824. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 42 (Octobre 2012) . - pp. 13815-13824 Mots-clés : Vertical  tube  Fluidized  bed  Fluidization  Bubble Résumé : The radial distribution of bubble characteristics such as the bubble frequency, the bubble size, and the bubble rise velocity, is a key to better understanding the flow patterns of gas (and solids) in bubbling fluidized beds. Therefore, the radial distribution of bubble characteristics is investigated in a fluidized bed with vertical tubes by means of optical probes. Measurements are taken for Geldart B particles at two bed heights, three gas velocities, and three vertical tube bank configurations. While the bubble frequency shows a strong dependence on the radial position in the bed and the orientation of the vertical tubes, the bubble size and the bubble rise velocity, in particular in the lower portions of the bed, are more constant. Typical bubble pathways are shown to move from the column wall to the center axis of the bed with increased bed height. Therefore, in order to have a representative mean bubble size and mean bubble rise velocity, which accounts for the whole cross-section of the bed, an area-number weighted mean is introduced. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26508205

Structured Packings for Multiphase Catalytic Reactors / Kalyani Pangarkar in Industrial & engineering chemistry research, Vol. 47 N°10 (Mai 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 N°10 (Mai 2008) . - p. 3720-3751 Titre : Structured Packings for Multiphase Catalytic Reactors Type de document : texte imprimé Auteurs : Kalyani Pangarkar, Auteur ; Tilman J. Schildhauer, Auteur ; J. Ruud van Ommen, Auteur Année de publication : 2008 Article en page(s) : p. 3720-3751 Langues : Anglais (eng) Mots-clés : Structured  packings Résumé : Reactor design for multiphase catalytic fixed bed reactors is always based on conflicting objectives. In the past, catalyst discovery and development preceded and motivated the selection of an appropriate multiphase reactor type. This type of sequential approach is increasingly been replaced by a parallel approach to catalyst and reactor selection. In nearly all respects, structured catalysts and reactors have the ability to outperform randomly packed reactors. Structured packings, apart from their advantages of high voidage and low-pressure drop, have the benefit of ease of scale-up and accurate description of the fluid mechanics. In this review we have evaluated the potential of using structured internals for multiphase catalytic reactions, which are currently carried out in randomly packed fixed bed reactors. Characteristics of various structured internals such as monoliths, corrugated sheet or gauze packings, knitted wire packings and foams are discussed in detail. Since designing a structured device for gas−liquid−solid contacting requires a sound knowledge of hydrodynamics and transport phenomena, a concise review of the above-mentioned structured packings and their characteristics based on hydrodynamics and transport phenomena is presented. Existing models (empirical, phenomenological and mechanistic) are outlined with respect to flow regime transition, pressure drop, liquid hold-up, gas−liquid interfacial area, gas to liquid mass transfer, liquid to solid mass transfer, residence time distribution (RTD), and heat transfer. The models are critically evaluated, and their limitations are discussed. An overview is given about what information is available, what needs to be evaluated and what kind of existing methodology can be applied in order to arrive at quantitative models for the physical parameters. Last, the structured internals are compared with each other and with randomly packed bed reactors, allowing a rational selection of the preferred packing for a given application. En ligne : https://pubs.acs.org/doi/abs/10.1021/ie800067r [article] Structured Packings for Multiphase Catalytic Reactors [texte imprimé] / Kalyani Pangarkar, Auteur ; Tilman J. Schildhauer, Auteur ; J. Ruud van Ommen, Auteur . - 2008 . - p. 3720-3751. Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 N°10 (Mai 2008) . - p. 3720-3751 Mots-clés : Structured  packings Résumé : Reactor design for multiphase catalytic fixed bed reactors is always based on conflicting objectives. In the past, catalyst discovery and development preceded and motivated the selection of an appropriate multiphase reactor type. This type of sequential approach is increasingly been replaced by a parallel approach to catalyst and reactor selection. In nearly all respects, structured catalysts and reactors have the ability to outperform randomly packed reactors. Structured packings, apart from their advantages of high voidage and low-pressure drop, have the benefit of ease of scale-up and accurate description of the fluid mechanics. In this review we have evaluated the potential of using structured internals for multiphase catalytic reactions, which are currently carried out in randomly packed fixed bed reactors. Characteristics of various structured internals such as monoliths, corrugated sheet or gauze packings, knitted wire packings and foams are discussed in detail. Since designing a structured device for gas−liquid−solid contacting requires a sound knowledge of hydrodynamics and transport phenomena, a concise review of the above-mentioned structured packings and their characteristics based on hydrodynamics and transport phenomena is presented. Existing models (empirical, phenomenological and mechanistic) are outlined with respect to flow regime transition, pressure drop, liquid hold-up, gas−liquid interfacial area, gas to liquid mass transfer, liquid to solid mass transfer, residence time distribution (RTD), and heat transfer. The models are critically evaluated, and their limitations are discussed. An overview is given about what information is available, what needs to be evaluated and what kind of existing methodology can be applied in order to arrive at quantitative models for the physical parameters. Last, the structured internals are compared with each other and with randomly packed bed reactors, allowing a rational selection of the preferred packing for a given application. En ligne : https://pubs.acs.org/doi/abs/10.1021/ie800067r