Documents disponibles écrits par cet auteur

Comparison of formic and sulfuric acids as a glucose decomposition catalyst / Laura Kupiainen in Industrial & engineering chemistry research, Vol. 49 N° 18 (Septembre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8444–8449 Titre : Comparison of formic and sulfuric acids as a glucose decomposition catalyst Type de document : texte imprimé Auteurs : Laura Kupiainen, Auteur ; Juha Ahola, Auteur ; Juha Tanskanen, Auteur Année de publication : 2010 Article en page(s) : pp. 8444–8449 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Sulfuric  acids  Catalyst Résumé : Dilute sulfuric acid hydrolysis of cellulose is the oldest and a well-studied technology for converting biomass to ethanol. Despite continuous technology improvements, the process still gives only a moderate selectivity due to glucose decomposition in the cellulose hydrolysis conditions. According to the recent literature, carboxylic acids have been recognized as more selective acid hydrolysis catalysts than sulfuric acid in low hydrogen ion concentrations. In this paper, formic acid was compared to sulfuric acid as a glucose decomposition catalyst at values below pH 2.2 at 180−220 °C. It was found that glucose decomposition depends only on the hydrogen ion concentration in the prevailing reaction conditions and is independent of the hydrogen ion source. Earlier contradictory findings can be the consequence of ignoring the temperature function of the dissociation constants of the acids and setting hydrogen ion concentrations at room temperature. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1008822 [article] Comparison of formic and sulfuric acids as a glucose decomposition catalyst [texte imprimé] / Laura Kupiainen, Auteur ; Juha Ahola, Auteur ; Juha Tanskanen, Auteur . - 2010 . - pp. 8444–8449. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8444–8449 Mots-clés : Sulfuric  acids  Catalyst Résumé : Dilute sulfuric acid hydrolysis of cellulose is the oldest and a well-studied technology for converting biomass to ethanol. Despite continuous technology improvements, the process still gives only a moderate selectivity due to glucose decomposition in the cellulose hydrolysis conditions. According to the recent literature, carboxylic acids have been recognized as more selective acid hydrolysis catalysts than sulfuric acid in low hydrogen ion concentrations. In this paper, formic acid was compared to sulfuric acid as a glucose decomposition catalyst at values below pH 2.2 at 180−220 °C. It was found that glucose decomposition depends only on the hydrogen ion concentration in the prevailing reaction conditions and is independent of the hydrogen ion source. Earlier contradictory findings can be the consequence of ignoring the temperature function of the dissociation constants of the acids and setting hydrogen ion concentrations at room temperature. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1008822

Kinetics of xylose dehydration into furfural in formic acid / Kaisa Lamminpaa in Industrial & engineering chemistry research, Vol. 51 N° 18 (Mai 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 18 (Mai 2012) . - pp. 6297-6303 Titre : Kinetics of xylose dehydration into furfural in formic acid Type de document : texte imprimé Auteurs : Kaisa Lamminpaa, Auteur ; Juha Ahola, Auteur ; Juha Tanskanen, Auteur Année de publication : 2012 Article en page(s) : pp. 6297-6303 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Dehydration  Kinetics Résumé : In this study, kinetics of formic add-catalyzed xylose dehydration into furfural and furfural decomposition was investigated using batch experiments within a temperature range of 130-200 °C. Initial xylose and furfural concentrations up to 0.2 and 0.08 mol/L, respectively, were used. The room temperature pH of the formic add catalyst solution was between 0.9 and 1.7. The kinetic model used was based on a specific acid catalysis model and included the prevailing hydrogen ion concentration in reaction conditions. The study showed that the modeling must account for other reactions for xylose besides dehydration into furfural. Moreover, the reactions between xylose intermediate and furfural play only a minor role. The study also showed that kinetic modeling of xylose and furfural decomposition reactions must take the uncatalyzed reaction in water solvent into account. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25867280 [article] Kinetics of xylose dehydration into furfural in formic acid [texte imprimé] / Kaisa Lamminpaa, Auteur ; Juha Ahola, Auteur ; Juha Tanskanen, Auteur . - 2012 . - pp. 6297-6303. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 18 (Mai 2012) . - pp. 6297-6303 Mots-clés : Dehydration  Kinetics Résumé : In this study, kinetics of formic add-catalyzed xylose dehydration into furfural and furfural decomposition was investigated using batch experiments within a temperature range of 130-200 °C. Initial xylose and furfural concentrations up to 0.2 and 0.08 mol/L, respectively, were used. The room temperature pH of the formic add catalyst solution was between 0.9 and 1.7. The kinetic model used was based on a specific acid catalysis model and included the prevailing hydrogen ion concentration in reaction conditions. The study showed that the modeling must account for other reactions for xylose besides dehydration into furfural. Moreover, the reactions between xylose intermediate and furfural play only a minor role. The study also showed that kinetic modeling of xylose and furfural decomposition reactions must take the uncatalyzed reaction in water solvent into account. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25867280

Modified bounded homotopies in the solving of phase stability problems for liquid-liquid phase-splitting calculations / Jani Kangas in Industrial & engineering chemistry research, Vol. 50 N° 11 (Juin 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 11 (Juin 2011) . - pp. 7003-7018 Titre : Modified bounded homotopies in the solving of phase stability problems for liquid-liquid phase-splitting calculations Type de document : texte imprimé Auteurs : Jani Kangas, Auteur ; Ilkka Malinen, Auteur ; Juha Tanskanen, Auteur Année de publication : 2011 Article en page(s) : pp. 7003-7018 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Liquid  phase  Phase  stability  Homotopy Résumé : In this study, the modified bounded homotopies presented by Malinen and Tanskanen (Malinen, L; Tanskanen, J. Modified bounded homotopies to enable a narrow bounding zone. Chem. Eng. Sci. 2008, 63, 3419) are investigated in order to solve phase stability analysis problems in liquid―liquid equilibrium cases for phase-splitting calculations. The tangent-plane distance criterion is used to analyze the phase stability. The emphasis is on approaching the first root on the homotopy path. According to the observations, the bounding of the homotopy path with respect to the problem variables aids in the solving of a phase stability analysis problem. The main shortcomings of the modified bounded Newton, affine, and fixed-point homotopies are the starting point isolas, the existence of unfeasible solutions, and the convergence to only certain roots, respectively. The attraction domain of the global minimum was observed to be the largest with the fixed-point homotopy. Sequential usage of the fixed-point homotopy and starting points near pure components results in a robust algorithm for phase stability analysis and gives feasible initial estimates for the solving of phase splitting. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24199919 [article] Modified bounded homotopies in the solving of phase stability problems for liquid-liquid phase-splitting calculations [texte imprimé] / Jani Kangas, Auteur ; Ilkka Malinen, Auteur ; Juha Tanskanen, Auteur . - 2011 . - pp. 7003-7018. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 11 (Juin 2011) . - pp. 7003-7018 Mots-clés : Liquid  phase  Phase  stability  Homotopy Résumé : In this study, the modified bounded homotopies presented by Malinen and Tanskanen (Malinen, L; Tanskanen, J. Modified bounded homotopies to enable a narrow bounding zone. Chem. Eng. Sci. 2008, 63, 3419) are investigated in order to solve phase stability analysis problems in liquid―liquid equilibrium cases for phase-splitting calculations. The tangent-plane distance criterion is used to analyze the phase stability. The emphasis is on approaching the first root on the homotopy path. According to the observations, the bounding of the homotopy path with respect to the problem variables aids in the solving of a phase stability analysis problem. The main shortcomings of the modified bounded Newton, affine, and fixed-point homotopies are the starting point isolas, the existence of unfeasible solutions, and the convergence to only certain roots, respectively. The attraction domain of the global minimum was observed to be the largest with the fixed-point homotopy. Sequential usage of the fixed-point homotopy and starting points near pure components results in a robust algorithm for phase stability analysis and gives feasible initial estimates for the solving of phase splitting. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24199919

Thermally coupled side-column configurations enabling distillation boundary crossing. 1. an overview and a solving procedure / Ilkka Malinen in Industrial & engineering chemistry research, Vol. 48 N° 13 (Juillet 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6387–6404 Titre : Thermally coupled side-column configurations enabling distillation boundary crossing. 1. an overview and a solving procedure Type de document : texte imprimé Auteurs : Ilkka Malinen, Auteur ; Juha Tanskanen, Auteur Année de publication : 2009 Article en page(s) : pp. 6387–6404 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Thermally  coupled  side-rectifier  Side-stripper  configurations  Component  sets  Curved  distillation  boundary Résumé : In this paper, the thermally coupled side-rectifier and side-stripper configurations are studied in the separation of component sets with a curved distillation boundary. A solving procedure is introduced that can be used in the determination of the minimum total energy consumption for the studied complex separation structures. The results show that thermally coupled side-column configurations enable distillation boundary crossing with high product flow purities. In fact, the achievable purities are higher than is possible with conventional column sequences. It is also noted that in some methanol/ethanol/water separations the energy consumption of the thermally coupled side-stripper configuration may partly decrease with increasing methanol distillate purity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800817n [article] Thermally coupled side-column configurations enabling distillation boundary crossing. 1. an overview and a solving procedure [texte imprimé] / Ilkka Malinen, Auteur ; Juha Tanskanen, Auteur . - 2009 . - pp. 6387–6404. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6387–6404 Mots-clés : Thermally  coupled  side-rectifier  Side-stripper  configurations  Component  sets  Curved  distillation  boundary Résumé : In this paper, the thermally coupled side-rectifier and side-stripper configurations are studied in the separation of component sets with a curved distillation boundary. A solving procedure is introduced that can be used in the determination of the minimum total energy consumption for the studied complex separation structures. The results show that thermally coupled side-column configurations enable distillation boundary crossing with high product flow purities. In fact, the achievable purities are higher than is possible with conventional column sequences. It is also noted that in some methanol/ethanol/water separations the energy consumption of the thermally coupled side-stripper configuration may partly decrease with increasing methanol distillate purity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800817n

Thermally coupled side-column configurations enabling distillation boundary crossing. 2. effects of intermediate heat exchangers / Ilkka Malinen in Industrial & engineering chemistry research, Vol. 48 N° 13 (Juillet 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6372–6386 Titre : Thermally coupled side-column configurations enabling distillation boundary crossing. 2. effects of intermediate heat exchangers Type de document : texte imprimé Auteurs : Ilkka Malinen, Auteur ; Juha Tanskanen, Auteur Année de publication : 2009 Article en page(s) : pp. 6372–6386 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Thermally  coupled  side-column  configurations  Heat  exchangers  Curved  distillation  boundary Résumé : In this paper, the benefits of intermediate heat exchangers situated in thermally coupled side-column configurations are examined in the separation of component sets having a curved distillation boundary. The simulation results indicate that by incorporating an intermediate heat exchanger the distillation boundary crossing can be enhanced. In consequence, pure product flows may be achieved with decreased total energy requirement. It is also found that thermally coupled side-column configurations having an intermediate heat exchanger require less energy to carry out the desired separation than do the corresponding conventional direct and indirect column schemes. Regardless of the increased complexity and possibility for multiple steady states, intermediate heat exchangers always improve thermodynamic efficiency and widen the potential for heat integration. This paper complements the study started in Part 1 [Malinen, I.; Tanskanen, J. Thermally coupled side-column configurations enabling distillation boundary crossing. 1. An Overview and a solving procedure. Ind. Eng. Chem. Res. 2009, 48, DOI: 10.1021/ie800817n] of this series of papers. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800818y [article] Thermally coupled side-column configurations enabling distillation boundary crossing. 2. effects of intermediate heat exchangers [texte imprimé] / Ilkka Malinen, Auteur ; Juha Tanskanen, Auteur . - 2009 . - pp. 6372–6386. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6372–6386 Mots-clés : Thermally  coupled  side-column  configurations  Heat  exchangers  Curved  distillation  boundary Résumé : In this paper, the benefits of intermediate heat exchangers situated in thermally coupled side-column configurations are examined in the separation of component sets having a curved distillation boundary. The simulation results indicate that by incorporating an intermediate heat exchanger the distillation boundary crossing can be enhanced. In consequence, pure product flows may be achieved with decreased total energy requirement. It is also found that thermally coupled side-column configurations having an intermediate heat exchanger require less energy to carry out the desired separation than do the corresponding conventional direct and indirect column schemes. Regardless of the increased complexity and possibility for multiple steady states, intermediate heat exchangers always improve thermodynamic efficiency and widen the potential for heat integration. This paper complements the study started in Part 1 [Malinen, I.; Tanskanen, J. Thermally coupled side-column configurations enabling distillation boundary crossing. 1. An Overview and a solving procedure. Ind. Eng. Chem. Res. 2009, 48, DOI: 10.1021/ie800817n] of this series of papers. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800818y