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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