Documents disponibles écrits par cet auteur

Dissolution of mineral fiber in a formic acid solution / Henrik Grenman ; Fernando Ramirez ; Kari Eranen in Industrial & engineering chemistry research, Vol. 47 n°24 (Décembre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°24 (Décembre 2008) . - p. 9834–9841 Titre : Dissolution of mineral fiber in a formic acid solution : kinetics, modeling, and gelation of the resulting sol Type de document : texte imprimé Auteurs : Henrik Grenman, Auteur ; Fernando Ramirez, Auteur ; Kari Eranen, Auteur Année de publication : 2009 Article en page(s) : p. 9834–9841 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Mineral  fiber Résumé : A new inorganic adhesive based on sol−gel technology has been developed recently. The sol is produced by dissolving a mineral material, with silica as the major compound, in formic acid. In this work, the kinetics and mechanisms of the solid−liquid reaction of the amorphous mineral raw material with formic acid were studied. The effect of different variables, such as temperature, acid concentration, and fiber load, were examined. Moreover, the influence of various parameters on the gelation rate of the resulting sol was investigated at different temperatures. The dissolution of the mineral fiber was found to be strongly dependent on the temperature and fiber load, but moderately dependent on the acid concentration as the pH of the solution was buffered by the formic acid. The kinetic model developed for the dissolution process accurately describes the experimental results and can thus be used for design and optimization of the process. The gelation studies showed that the temperature and the amount dissolved are the variables most affecting the gelation time. The knowledge of the gelation kinetics is important when striving for a high dry solid content in the sol, while still avoiding premature gelation in production, transport, and storage. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800267a [article] Dissolution of mineral fiber in a formic acid solution : kinetics, modeling, and gelation of the resulting sol [texte imprimé] / Henrik Grenman, Auteur ; Fernando Ramirez, Auteur ; Kari Eranen, Auteur . - 2009 . - p. 9834–9841. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°24 (Décembre 2008) . - p. 9834–9841 Mots-clés : Mineral  fiber Résumé : A new inorganic adhesive based on sol−gel technology has been developed recently. The sol is produced by dissolving a mineral material, with silica as the major compound, in formic acid. In this work, the kinetics and mechanisms of the solid−liquid reaction of the amorphous mineral raw material with formic acid were studied. The effect of different variables, such as temperature, acid concentration, and fiber load, were examined. Moreover, the influence of various parameters on the gelation rate of the resulting sol was investigated at different temperatures. The dissolution of the mineral fiber was found to be strongly dependent on the temperature and fiber load, but moderately dependent on the acid concentration as the pH of the solution was buffered by the formic acid. The kinetic model developed for the dissolution process accurately describes the experimental results and can thus be used for design and optimization of the process. The gelation studies showed that the temperature and the amount dissolved are the variables most affecting the gelation time. The knowledge of the gelation kinetics is important when striving for a high dry solid content in the sol, while still avoiding premature gelation in production, transport, and storage. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800267a

Kinetics of aqueous extraction of hemicelluloses from spruce in an intensified reactor system / Henrik Grenman in Industrial & engineering chemistry research, Vol. 50 N° 7 (Avril 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 7 (Avril 2011) . - pp. 3818–3828 Titre : Kinetics of aqueous extraction of hemicelluloses from spruce in an intensified reactor system Type de document : texte imprimé Auteurs : Henrik Grenman, Auteur ; Kari Eranen, Auteur ; Jens Krogell, Auteur Année de publication : 2011 Article en page(s) : pp. 3818–3828 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Kinetics Résumé : The aqueous extraction of hemicelluloses has gained increasing interest with new emerging applications for hemicelluloses in the modern forest-based biorefinery concept. The extraction kinetics play a key role in their industrial utilization. The traditional kinetic studies and models for the selective dissolution of softwoods, however, always incorporate high concentrations of sodium hydroxide and sodium sulfide relevant to pulping, and the kinetics in pure water is left outside the scope of these investigations. Aqueous extraction of hemicelluloses from spruce sapwood was investigated with a new cascade reactor setup, which was developed for intensified investigation of solid−liquid dissolution kinetics. The experiments were performed at 150−170 °C with a particle size of 1.25−2 mm and solid loads of about 6.25 g of dry wood/L in the kinetic regime of intrinsic kinetics. The pH of the liquid phase was measured during the reaction. The selectivity of the dissolution and degradation of hemicelluloses was examined qualitatively. The total concentrations of arabinose (Ara), xylose (Xyl), galactose (Gal), glucose (Glc), mannose (Man), rhamnose (Rha), glucuronic acid (GlcA), 4-O-methylglucuronic acid (4-O-MeGlcA), and galacturonic acid (GalA) were analyzed from the liquid and solid phases during the reaction. The dissolution was observed to be highly temperature dependent, and degradation of the compounds was observed. A kinetic model was developed for the overall extraction of the hemicelluloses. The activation energy was determined to be 135 kJ/mol. No significant influence of the pH on the actual extraction kinetics was observed, even though it influences strongly the degradation of the compounds through hydrolysis. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101946c [article] Kinetics of aqueous extraction of hemicelluloses from spruce in an intensified reactor system [texte imprimé] / Henrik Grenman, Auteur ; Kari Eranen, Auteur ; Jens Krogell, Auteur . - 2011 . - pp. 3818–3828. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 7 (Avril 2011) . - pp. 3818–3828 Mots-clés : Kinetics Résumé : The aqueous extraction of hemicelluloses has gained increasing interest with new emerging applications for hemicelluloses in the modern forest-based biorefinery concept. The extraction kinetics play a key role in their industrial utilization. The traditional kinetic studies and models for the selective dissolution of softwoods, however, always incorporate high concentrations of sodium hydroxide and sodium sulfide relevant to pulping, and the kinetics in pure water is left outside the scope of these investigations. Aqueous extraction of hemicelluloses from spruce sapwood was investigated with a new cascade reactor setup, which was developed for intensified investigation of solid−liquid dissolution kinetics. The experiments were performed at 150−170 °C with a particle size of 1.25−2 mm and solid loads of about 6.25 g of dry wood/L in the kinetic regime of intrinsic kinetics. The pH of the liquid phase was measured during the reaction. The selectivity of the dissolution and degradation of hemicelluloses was examined qualitatively. The total concentrations of arabinose (Ara), xylose (Xyl), galactose (Gal), glucose (Glc), mannose (Man), rhamnose (Rha), glucuronic acid (GlcA), 4-O-methylglucuronic acid (4-O-MeGlcA), and galacturonic acid (GalA) were analyzed from the liquid and solid phases during the reaction. The dissolution was observed to be highly temperature dependent, and degradation of the compounds was observed. A kinetic model was developed for the overall extraction of the hemicelluloses. The activation energy was determined to be 135 kJ/mol. No significant influence of the pH on the actual extraction kinetics was observed, even though it influences strongly the degradation of the compounds through hydrolysis. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101946c

Modeling the influence of wood anisotropy and internal diffusion on delignification kinetics / Henrik Grenman in Industrial & engineering chemistry research, Vol. 49 N° 20 (Octobre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9703–9711 Titre : Modeling the influence of wood anisotropy and internal diffusion on delignification kinetics Type de document : texte imprimé Auteurs : Henrik Grenman, Auteur ; Johan Warna, Auteur ; J.-P. Mikkola, Auteur Année de publication : 2011 Article en page(s) : pp. 9703–9711 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Kinetics  Internal  diffusion  Anisotropy  Wood  Modeling Résumé : A general mathematical model for the chemical pulping of wood including coupled chemical reactions and diffusion limitations in anisotropic wood chips was developed. The model, which consists of coupled parabolic partial differential equations (PDEs) and ordinary differential equations (ODEs), describes the time-dependent behavior of wood chips as they are exposed to chemicals in the liquid phase. In addition to the reaction−diffusion phenomena, the model describes the change of the wood chip porosity during the process. A numerical algorithm that combines spatial discretization by finite differences with a stiff ODE solver based on the backward difference method was used as an efficient strategy to solve the mass balances of wood chips in batch reactors. Numerical simulations with the software can be used to predict the progress of industrial delignification, that is, production of primarily cellulose through chemical pulping. The effect of the reaction parameters, such as the temperature and the concentrations of the alkaline delignification chemicals, as well as the sizes of the wood chips, can be evaluated with the model, the final goal being the intensification of the chemical pulping process. The model can be used to describe both the current kraft pulping (sulfate pulping) technique, as well as other processes, such as sulfite pulping and pulping in nonaqueous solvents. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325789 [article] Modeling the influence of wood anisotropy and internal diffusion on delignification kinetics [texte imprimé] / Henrik Grenman, Auteur ; Johan Warna, Auteur ; J.-P. Mikkola, Auteur . - 2011 . - pp. 9703–9711. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9703–9711 Mots-clés : Kinetics  Internal  diffusion  Anisotropy  Wood  Modeling Résumé : A general mathematical model for the chemical pulping of wood including coupled chemical reactions and diffusion limitations in anisotropic wood chips was developed. The model, which consists of coupled parabolic partial differential equations (PDEs) and ordinary differential equations (ODEs), describes the time-dependent behavior of wood chips as they are exposed to chemicals in the liquid phase. In addition to the reaction−diffusion phenomena, the model describes the change of the wood chip porosity during the process. A numerical algorithm that combines spatial discretization by finite differences with a stiff ODE solver based on the backward difference method was used as an efficient strategy to solve the mass balances of wood chips in batch reactors. Numerical simulations with the software can be used to predict the progress of industrial delignification, that is, production of primarily cellulose through chemical pulping. The effect of the reaction parameters, such as the temperature and the concentrations of the alkaline delignification chemicals, as well as the sizes of the wood chips, can be evaluated with the model, the final goal being the intensification of the chemical pulping process. The model can be used to describe both the current kraft pulping (sulfate pulping) technique, as well as other processes, such as sulfite pulping and pulping in nonaqueous solvents. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23325789

The dissolution kinetics of gibbsite in sodium hydroxide at ambient pressure / Henrik Grenman in Industrial & engineering chemistry research, Vol. 49 N° 6 (Mars 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 6 (Mars 2010) . - pp. 2600–2607 Titre : The dissolution kinetics of gibbsite in sodium hydroxide at ambient pressure Type de document : texte imprimé Auteurs : Henrik Grenman, Auteur ; Tapio Salmi, Auteur ; Dmitry Yu, Auteur Année de publication : 2010 Article en page(s) : pp. 2600–2607 Note générale : Industrial Chemistry Langues : Anglais (eng) Mots-clés : Dissolution  Kinetics  Gibbsite  Sodium  Hydroxide  Ambient  Pressure Résumé : The dissolution kinetics of pure gibbsite in concentrated sodium hydroxide solutions was studied. The experiments were performed under ambient pressure and at 60−85 °C. The changes in morphology of the solid phase were studied during the reaction by particle size, porosity, and surface area measurements as well as scanning electron microscopy. Reaction rates were observed to be strongly dependent on temperature and hydroxide concentration. Several kinetic models, based on different representation of the surface area of gibbsite, were compared to the experimental data and a good correlation between a model incorporating rough/porous geometry and the experimental data was obtained. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901803v [article] The dissolution kinetics of gibbsite in sodium hydroxide at ambient pressure [texte imprimé] / Henrik Grenman, Auteur ; Tapio Salmi, Auteur ; Dmitry Yu, Auteur . - 2010 . - pp. 2600–2607. Industrial Chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 6 (Mars 2010) . - pp. 2600–2607 Mots-clés : Dissolution  Kinetics  Gibbsite  Sodium  Hydroxide  Ambient  Pressure Résumé : The dissolution kinetics of pure gibbsite in concentrated sodium hydroxide solutions was studied. The experiments were performed under ambient pressure and at 60−85 °C. The changes in morphology of the solid phase were studied during the reaction by particle size, porosity, and surface area measurements as well as scanning electron microscopy. Reaction rates were observed to be strongly dependent on temperature and hydroxide concentration. Several kinetic models, based on different representation of the surface area of gibbsite, were compared to the experimental data and a good correlation between a model incorporating rough/porous geometry and the experimental data was obtained. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901803v