Documents disponibles écrits par cet auteur

Effects of feed composition and feed impurities in the catalytic conversion of syngas to higher alcohols over alkali-promoted cobalt-molybdenum sulfide / Jakob M. Christensen in Industrial & engineering chemistry research, Vol. 50 N° 13 (Juillet 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 13 (Juillet 2011) . - pp. 7949-7963 Titre : Effects of feed composition and feed impurities in the catalytic conversion of syngas to higher alcohols over alkali-promoted cobalt-molybdenum sulfide Type de document : texte imprimé Auteurs : Jakob M. Christensen, Auteur ; Peter A. Jensen, Auteur ; Anker D. Jensen, Auteur Année de publication : 2011 Article en page(s) : pp. 7949-7963 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Synthesis  gas  Catalytic  conversion  Impurity Résumé : Alkali-promoted cobalt-molybdenum sulfide is a potential catalyst for the conversion of syngas into higher alcohols. This work is an investigation of how the feed composition influences the behavior of the sulfide catalyst. In a sulfur-free syngas the production of higher alcohols is observed to be optimal with an equimolar mixture of CO and H2 in the feed, while the methanol production benefits from an increasing hydrogen content in the feed. The influence of NH3 and H2O in the syngas feed has also been investigated. Ammonia (741 ppmv) in the feed is observed to cause a general and largely reversible deactivation of the catalyst. Operation with elevated water levels in the syngas feed (4.7-13.4 mol %) is observed to cause a deactivation of the catalyst, and it is especially the chain growth that is affected. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24332119 [article] Effects of feed composition and feed impurities in the catalytic conversion of syngas to higher alcohols over alkali-promoted cobalt-molybdenum sulfide [texte imprimé] / Jakob M. Christensen, Auteur ; Peter A. Jensen, Auteur ; Anker D. Jensen, Auteur . - 2011 . - pp. 7949-7963. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 13 (Juillet 2011) . - pp. 7949-7963 Mots-clés : Synthesis  gas  Catalytic  conversion  Impurity Résumé : Alkali-promoted cobalt-molybdenum sulfide is a potential catalyst for the conversion of syngas into higher alcohols. This work is an investigation of how the feed composition influences the behavior of the sulfide catalyst. In a sulfur-free syngas the production of higher alcohols is observed to be optimal with an equimolar mixture of CO and H2 in the feed, while the methanol production benefits from an increasing hydrogen content in the feed. The influence of NH3 and H2O in the syngas feed has also been investigated. Ammonia (741 ppmv) in the feed is observed to cause a general and largely reversible deactivation of the catalyst. Operation with elevated water levels in the syngas feed (4.7-13.4 mol %) is observed to cause a deactivation of the catalyst, and it is especially the chain growth that is affected. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24332119

Fluidized-bed coating with sodium sulfate and PVA-TiO2, 1. Review and agglomeration regime maps / Peter Dybdahl Hede 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. 1893–1904 Titre : Fluidized-bed coating with sodium sulfate and PVA-TiO2, 1. Review and agglomeration regime maps Type de document : texte imprimé Auteurs : Peter Dybdahl Hede, Auteur ; Poul Bach, Auteur ; Anker D. Jensen, Auteur Année de publication : 2009 Article en page(s) : pp. 1893–1904 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Placebo  enzyme  granules  Fluid-bed  coating  Sodium  sulfate  Polyvinyl  alcohol-titanium  dioxide  Inorganic  salt  Ppolymer  film  coating Résumé : This paper, and two associated papers [Hede, P. D.; Jensen, A. D.; Bach, P. Ind. Eng. Chem. Res. 2009, 48, 1905 and 1914], address the fluid-bed coating of placebo enzyme granules (i.e., sodium sulfate cores, with a size range of 400−500 μm) using two types of coatings: sodium sulfate and PVA−TiO2. The coating experiments were conducted in a medium-scale top-spray MP-1 fluid bed, and many rheological experiments were performed on the coating formulations to support the interpretation of the fluid-bed coating results. In this first part of the study, a thorough introduction to the inorganic salt and polymer film coating is provided, along with a presentation of the equipment and materials being used in this and the following papers. Results from agglomeration studies over a broad range of process conditions are presented, showing that the tendency toward agglomeration is always less for the salt coating process than for the polymer coating process, under similar process conditions. Based on the experimental results, an agglomeration regime map is suggested for each of the two types of coating solutions, based on values of the drying force and the coating solution spray rate. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800940e [article] Fluidized-bed coating with sodium sulfate and PVA-TiO2, 1. Review and agglomeration regime maps [texte imprimé] / Peter Dybdahl Hede, Auteur ; Poul Bach, Auteur ; Anker D. Jensen, Auteur . - 2009 . - pp. 1893–1904. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1893–1904 Mots-clés : Placebo  enzyme  granules  Fluid-bed  coating  Sodium  sulfate  Polyvinyl  alcohol-titanium  dioxide  Inorganic  salt  Ppolymer  film  coating Résumé : This paper, and two associated papers [Hede, P. D.; Jensen, A. D.; Bach, P. Ind. Eng. Chem. Res. 2009, 48, 1905 and 1914], address the fluid-bed coating of placebo enzyme granules (i.e., sodium sulfate cores, with a size range of 400−500 μm) using two types of coatings: sodium sulfate and PVA−TiO2. The coating experiments were conducted in a medium-scale top-spray MP-1 fluid bed, and many rheological experiments were performed on the coating formulations to support the interpretation of the fluid-bed coating results. In this first part of the study, a thorough introduction to the inorganic salt and polymer film coating is provided, along with a presentation of the equipment and materials being used in this and the following papers. Results from agglomeration studies over a broad range of process conditions are presented, showing that the tendency toward agglomeration is always less for the salt coating process than for the polymer coating process, under similar process conditions. Based on the experimental results, an agglomeration regime map is suggested for each of the two types of coating solutions, based on values of the drying force and the coating solution spray rate. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800940e

Fluidized-bed coating with sodium sulfate and PVA-TiO2, 2. Influence of coating solution viscosity, stickiness, pH, and droplet diameter on agglomeration / Peter Dybdahl Hede 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. 1905–1913 Titre : Fluidized-bed coating with sodium sulfate and PVA-TiO2, 2. Influence of coating solution viscosity, stickiness, pH, and droplet diameter on agglomeration Type de document : texte imprimé Auteurs : Peter Dybdahl Hede, Auteur ; Poul Bach, Auteur ; Anker D. Jensen, Auteur Année de publication : 2009 Article en page(s) : pp. 1905–1913 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Coating  stickiness  Bulk  viscosities  PVA-TiO2  coating  Salt  coating  process Résumé : In the first part of this study [Hede, P. D.; Bach, P.; Jensen, A. D. Ind. Eng. Chem. Res. 2009, 49, 1914], agglomeration regime maps were developed for two types of coatings: sodium sulfate and PVA−TiO2. It was observed here how the agglomeration tendency is always lower for the salt coating process than for the polymer coating process, under similar process conditions. This is investigated further in this second part and concluded to be due to differences in coating solution stickiness, rather than differences in bulk viscosities. Furthermore, results show that it is possible to optimize the PVA−TiO2 coating formulation and process to achieve a low tendency of agglomeration, similar to that of the salt coating process. The best results for the PVA−TiO2 solution are obtained by substituting the PVA−TiO2 in equal amounts with Neodol 23-6.5 and further reducing the pH value in the coating solution to pH 4. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800941x [article] Fluidized-bed coating with sodium sulfate and PVA-TiO2, 2. Influence of coating solution viscosity, stickiness, pH, and droplet diameter on agglomeration [texte imprimé] / Peter Dybdahl Hede, Auteur ; Poul Bach, Auteur ; Anker D. Jensen, Auteur . - 2009 . - pp. 1905–1913. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1905–1913 Mots-clés : Coating  stickiness  Bulk  viscosities  PVA-TiO2  coating  Salt  coating  process Résumé : In the first part of this study [Hede, P. D.; Bach, P.; Jensen, A. D. Ind. Eng. Chem. Res. 2009, 49, 1914], agglomeration regime maps were developed for two types of coatings: sodium sulfate and PVA−TiO2. It was observed here how the agglomeration tendency is always lower for the salt coating process than for the polymer coating process, under similar process conditions. This is investigated further in this second part and concluded to be due to differences in coating solution stickiness, rather than differences in bulk viscosities. Furthermore, results show that it is possible to optimize the PVA−TiO2 coating formulation and process to achieve a low tendency of agglomeration, similar to that of the salt coating process. The best results for the PVA−TiO2 solution are obtained by substituting the PVA−TiO2 in equal amounts with Neodol 23-6.5 and further reducing the pH value in the coating solution to pH 4. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800941x

Fluidized-bed coating with sodium sulfate and PVA-TiO2, 3. The role of tackiness and the tack stokes number / Peter Dybdahl Hede 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. 1914–1920 Titre : Fluidized-bed coating with sodium sulfate and PVA-TiO2, 3. The role of tackiness and the tack stokes number Type de document : texte imprimé Auteurs : Peter Dybdahl Hede, Auteur ; Poul Bach, Auteur ; Anker D. Jensen, Auteur Année de publication : 2009 Article en page(s) : pp. 1914–1920 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Fluid-bed  coating  processes  PVA−TiO2  coating  Liquid  surface  phenomena  Stokes  number Résumé : In the first and second parts of this study [Hede, P. D.; Bach, P.; Jensen, A. D. Ind. Eng. Chem. Res. 2009, 48, 1893 and 1905], agglomeration tendencies were studied for two types of coatings: sodium sulfate and PVA−TiO2. Results showed that the agglomeration tendency is always lower for the salt coating process than for the polymer coating process, under similar process conditions, because of differences in stickiness, not because of differences in bulk viscosities. It was further shown that it is possible to optimize the PVA−TiO2 coating formulation and process to achieve a low tendency of agglomeration, similar to the salt coating process. With the PVA−TiO2 coating liquid layer thicknesses encountered during these fluid-bed coating processes, agglomeration seems to be governed primarily by liquid surface phenomena. A modification to the original viscous Stokes number is suggested in the present paper, which defines the Stokes number in terms of the work needed to reach maximum tack instead of the viscous dissipation energy. The new tack Stokes number correlates well with the observed levels of agglomeration and, as a promising feature, proportionality is observed between the agglomeration weight percentage and the difference between the new tack Stokes number and the critical tack Stokes number. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800942c [article] Fluidized-bed coating with sodium sulfate and PVA-TiO2, 3. The role of tackiness and the tack stokes number [texte imprimé] / Peter Dybdahl Hede, Auteur ; Poul Bach, Auteur ; Anker D. Jensen, Auteur . - 2009 . - pp. 1914–1920. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - pp. 1914–1920 Mots-clés : Fluid-bed  coating  processes  PVA−TiO2  coating  Liquid  surface  phenomena  Stokes  number Résumé : In the first and second parts of this study [Hede, P. D.; Bach, P.; Jensen, A. D. Ind. Eng. Chem. Res. 2009, 48, 1893 and 1905], agglomeration tendencies were studied for two types of coatings: sodium sulfate and PVA−TiO2. Results showed that the agglomeration tendency is always lower for the salt coating process than for the polymer coating process, under similar process conditions, because of differences in stickiness, not because of differences in bulk viscosities. It was further shown that it is possible to optimize the PVA−TiO2 coating formulation and process to achieve a low tendency of agglomeration, similar to the salt coating process. With the PVA−TiO2 coating liquid layer thicknesses encountered during these fluid-bed coating processes, agglomeration seems to be governed primarily by liquid surface phenomena. A modification to the original viscous Stokes number is suggested in the present paper, which defines the Stokes number in terms of the work needed to reach maximum tack instead of the viscous dissipation energy. The new tack Stokes number correlates well with the observed levels of agglomeration and, as a promising feature, proportionality is observed between the agglomeration weight percentage and the difference between the new tack Stokes number and the critical tack Stokes number. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800942c