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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