Documents disponibles écrits par cet auteur

Adsorption of proteins onto ion-exchange chromatographic media / Juan Liang in Industrial & engineering chemistry research, Vol. 51 N° 49 (Décembre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 49 (Décembre 2012) . - pp. 16049-16058 Titre : Adsorption of proteins onto ion-exchange chromatographic media : A molecular dynamics study Type de document : texte imprimé Auteurs : Juan Liang, Auteur ; Georg Fieg, Auteur ; Frerich J. Keil, Auteur Année de publication : 2013 Article en page(s) : pp. 16049-16058 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Molecular  dynamics  method  Ion  exchange  Adsorption Résumé : Molecular dynamics (MD) simulations with coarse-grained models are used to investigate the adsorption process of proteins onto an ion-exchange chromatographic medium. The adsorption of human serum albumin (HSA) and bovine hemoglobin (bHb) on the anion exchanger Q Sepharose FF is studied. These two proteins have similar molecule sizes with different isoelectric points. To obtain a reliable set of data, simulations with different initial conditions are carried out for each protein. Convincingly, the results of the MD simulations are qualitatively consistent with those of previous experiments. HSA reaches a stable adsorption in all simulations, while the binding sites can differ. In contrast, bHb reaches a stable adsorption only in one simulation. Due to the stronger protein—ligand interaction of HSA, it adsorbs faster, stronger, and with more binding sites onto QSepharose FF than bHb. The spatial movements during the adsorption process and the adsorbed states are investigated in detail. Moreover, we studied the underlying physical relevance of two parameters (characteristic charge and steric factor) of the steric mass action (SMA) model for HSA and for bHb with MD simulations and compared them with the results of experiments. The results reveal that MD simulations are useful to interpret the physical consistence of the SMA parameters. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26732130 [article] Adsorption of proteins onto ion-exchange chromatographic media : A molecular dynamics study [texte imprimé] / Juan Liang, Auteur ; Georg Fieg, Auteur ; Frerich J. Keil, Auteur . - 2013 . - pp. 16049-16058. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 49 (Décembre 2012) . - pp. 16049-16058 Mots-clés : Molecular  dynamics  method  Ion  exchange  Adsorption Résumé : Molecular dynamics (MD) simulations with coarse-grained models are used to investigate the adsorption process of proteins onto an ion-exchange chromatographic medium. The adsorption of human serum albumin (HSA) and bovine hemoglobin (bHb) on the anion exchanger Q Sepharose FF is studied. These two proteins have similar molecule sizes with different isoelectric points. To obtain a reliable set of data, simulations with different initial conditions are carried out for each protein. Convincingly, the results of the MD simulations are qualitatively consistent with those of previous experiments. HSA reaches a stable adsorption in all simulations, while the binding sites can differ. In contrast, bHb reaches a stable adsorption only in one simulation. Due to the stronger protein—ligand interaction of HSA, it adsorbs faster, stronger, and with more binding sites onto QSepharose FF than bHb. The spatial movements during the adsorption process and the adsorbed states are investigated in detail. Moreover, we studied the underlying physical relevance of two parameters (characteristic charge and steric factor) of the steric mass action (SMA) model for HSA and for bHb with MD simulations and compared them with the results of experiments. The results reveal that MD simulations are useful to interpret the physical consistence of the SMA parameters. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26732130

Applicability of a countercurrent enzymatically catalyzed multistage extractive reaction process for the hydrolysis of methyl octanoate / Przemyslaw Krause in Industrial & engineering chemistry research, Vol. 49 N° 7 (Avril 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 7 (Avril 2010) . - pp. 3217–3222 Titre : Applicability of a countercurrent enzymatically catalyzed multistage extractive reaction process for the hydrolysis of methyl octanoate Type de document : texte imprimé Auteurs : Przemyslaw Krause, Auteur ; Roberto Macias, Auteur ; Georg Fieg, Auteur Année de publication : 2010 Article en page(s) : pp. 3217–3222 Note générale : Industrial Chemistry Langues : Anglais (eng) Mots-clés : Enzymatically  Catalyzed  Multistage  Methyl  Octanoate Résumé : An assessment of the minimum requirements for a countercurrent multistage extractive reaction process for the enzymatic hydrolysis of methyl octanoate with immobilized lipase in undiluted media was made. For simulation, UNIQUAC parameters for the quaternary reaction system containing methyl octanoate, octanoic acid, methanol, and water at 48.5 °C and atmospheric pressure and the equilibrium conversion, as a function of the initial water content, were determined. For a one-equilibrium stage reaction, good overall agreement, with respect to the liquid-phase compositions between experiments, and results from chemical and phase equilibrium calculations, based on Gibbs free-energy minimization, was obtained. A subsequently performed analysis of the influence of the stage number and solvent:feed ratio, using commercial flowsheet simulation software, showed that, in a countercurrent process, five equilibrium stages are required to obtain octanoic acid with a purity exceeding mass fractions of 0.95 at comparably moderate water excess. ISSN : Methyl Octan En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901789p [article] Applicability of a countercurrent enzymatically catalyzed multistage extractive reaction process for the hydrolysis of methyl octanoate [texte imprimé] / Przemyslaw Krause, Auteur ; Roberto Macias, Auteur ; Georg Fieg, Auteur . - 2010 . - pp. 3217–3222. Industrial Chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 7 (Avril 2010) . - pp. 3217–3222 Mots-clés : Enzymatically  Catalyzed  Multistage  Methyl  Octanoate Résumé : An assessment of the minimum requirements for a countercurrent multistage extractive reaction process for the enzymatic hydrolysis of methyl octanoate with immobilized lipase in undiluted media was made. For simulation, UNIQUAC parameters for the quaternary reaction system containing methyl octanoate, octanoic acid, methanol, and water at 48.5 °C and atmospheric pressure and the equilibrium conversion, as a function of the initial water content, were determined. For a one-equilibrium stage reaction, good overall agreement, with respect to the liquid-phase compositions between experiments, and results from chemical and phase equilibrium calculations, based on Gibbs free-energy minimization, was obtained. A subsequently performed analysis of the influence of the stage number and solvent:feed ratio, using commercial flowsheet simulation software, showed that, in a countercurrent process, five equilibrium stages are required to obtain octanoic acid with a purity exceeding mass fractions of 0.95 at comparably moderate water excess. ISSN : Methyl Octan En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901789p

Experimental and theoretical studies of a dividing - wall column used for the recovery of high - purity products / Gerit Niggemann in Industrial & engineering chemistry research, Vol. 49 N° 14 (Juillet 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 14 (Juillet 2010) . - pp. 6566–6577 Titre : Experimental and theoretical studies of a dividing - wall column used for the recovery of high - purity products Type de document : texte imprimé Auteurs : Gerit Niggemann, Auteur ; Christoph Hiller, Auteur ; Georg Fieg, Auteur Année de publication : 2010 Article en page(s) : pp. 6566–6577 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Dividing  wall  columns. Résumé : Although dividing-wall columns are now well established in industrial practice, their complex hydraulics is not well understood, and open literature does not provide any quantitative information in this respect. This study aims to provide the missing knowledge. Hence, a pilot plant was built to separate a ternary mixture of fatty alcohols into high-purity products of 99 wt %. A model was established to simulate this separation process. It could successfully describe the experiments quantitatively and even account for the self-adjustment of the vapor splits. A case study with the validated model highlighted the strong influence of the heat transfer across the vertical partition wall on hydrodynamics and vapor distribution. These aspects are of special interest for the design and scale-up of dividing-wall columns. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1003416 [article] Experimental and theoretical studies of a dividing - wall column used for the recovery of high - purity products [texte imprimé] / Gerit Niggemann, Auteur ; Christoph Hiller, Auteur ; Georg Fieg, Auteur . - 2010 . - pp. 6566–6577. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 14 (Juillet 2010) . - pp. 6566–6577 Mots-clés : Dividing  wall  columns. Résumé : Although dividing-wall columns are now well established in industrial practice, their complex hydraulics is not well understood, and open literature does not provide any quantitative information in this respect. This study aims to provide the missing knowledge. Hence, a pilot plant was built to separate a ternary mixture of fatty alcohols into high-purity products of 99 wt %. A model was established to simulate this separation process. It could successfully describe the experiments quantitatively and even account for the self-adjustment of the vapor splits. A case study with the validated model highlighted the strong influence of the heat transfer across the vertical partition wall on hydrodynamics and vapor distribution. These aspects are of special interest for the design and scale-up of dividing-wall columns. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1003416

Experimental and theoretical studies on the start-up operation of a multivessel batch distillation column / Sven Gruetzmann in Industrial & engineering chemistry research, Vol. 48 N° 11 (Juin 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5336–5343 Titre : Experimental and theoretical studies on the start-up operation of a multivessel batch distillation column Type de document : texte imprimé Auteurs : Sven Gruetzmann, Auteur ; Georg Fieg, Auteur ; Sigurd Skogestad, Auteur Année de publication : 2009 Article en page(s) : pp. 5336–5343 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Multivessel  batch  distillation  Reflux  strategy  Start-up  period Résumé : Multivessel batch distillation is a promising alternative to conventional batch distillation. Earlier studies proved the feasibility of temperature control in a closed operation mode, that is, when no product is removed until the end of the process. In this article, the influence of the reflux strategy during the initial start-up period is investigated in detail. This is a very important task in terms of the development of automation procedures in an industrial realization. The work is divided into three main parts. First, a rigorous dynamic model is introduced to describe the behavior of a multivessel batch distillation during start-up. Then, two experiments carried out on a laboratory scale column were chosen to validate the model. Finally, a sensitivity study is presented observing composition response while changing the reflux strategy. The results show that the process can be improved by applying a high reflux ratio and establishing the hydraulics as soon as possible. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800962b [article] Experimental and theoretical studies on the start-up operation of a multivessel batch distillation column [texte imprimé] / Sven Gruetzmann, Auteur ; Georg Fieg, Auteur ; Sigurd Skogestad, Auteur . - 2009 . - pp. 5336–5343. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5336–5343 Mots-clés : Multivessel  batch  distillation  Reflux  strategy  Start-up  period Résumé : Multivessel batch distillation is a promising alternative to conventional batch distillation. Earlier studies proved the feasibility of temperature control in a closed operation mode, that is, when no product is removed until the end of the process. In this article, the influence of the reflux strategy during the initial start-up period is investigated in detail. This is a very important task in terms of the development of automation procedures in an industrial realization. The work is divided into three main parts. First, a rigorous dynamic model is introduced to describe the behavior of a multivessel batch distillation during start-up. Then, two experiments carried out on a laboratory scale column were chosen to validate the model. Finally, a sensitivity study is presented observing composition response while changing the reflux strategy. The results show that the process can be improved by applying a high reflux ratio and establishing the hydraulics as soon as possible. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800962b

Experimental and theoretical studies on the start-up operation of a multivessel batch distillation column / Sven Gruetzmann in Industrial & engineering chemistry research, Vol. 48 N° 11 (Juin 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5336–5343 Titre : Experimental and theoretical studies on the start-up operation of a multivessel batch distillation column Type de document : texte imprimé Auteurs : Sven Gruetzmann, Auteur ; Georg Fieg, Auteur ; Sigurd Skogestad, Auteur Année de publication : 2009 Article en page(s) : pp. 5336–5343 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Multivessel  batch  distillation  Reflux  strategy  Start-up  period Résumé : Multivessel batch distillation is a promising alternative to conventional batch distillation. Earlier studies proved the feasibility of temperature control in a closed operation mode, that is, when no product is removed until the end of the process. In this article, the influence of the reflux strategy during the initial start-up period is investigated in detail. This is a very important task in terms of the development of automation procedures in an industrial realization. The work is divided into three main parts. First, a rigorous dynamic model is introduced to describe the behavior of a multivessel batch distillation during start-up. Then, two experiments carried out on a laboratory scale column were chosen to validate the model. Finally, a sensitivity study is presented observing composition response while changing the reflux strategy. The results show that the process can be improved by applying a high reflux ratio and establishing the hydraulics as soon as possible. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800962b [article] Experimental and theoretical studies on the start-up operation of a multivessel batch distillation column [texte imprimé] / Sven Gruetzmann, Auteur ; Georg Fieg, Auteur ; Sigurd Skogestad, Auteur . - 2009 . - pp. 5336–5343. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5336–5343 Mots-clés : Multivessel  batch  distillation  Reflux  strategy  Start-up  period Résumé : Multivessel batch distillation is a promising alternative to conventional batch distillation. Earlier studies proved the feasibility of temperature control in a closed operation mode, that is, when no product is removed until the end of the process. In this article, the influence of the reflux strategy during the initial start-up period is investigated in detail. This is a very important task in terms of the development of automation procedures in an industrial realization. The work is divided into three main parts. First, a rigorous dynamic model is introduced to describe the behavior of a multivessel batch distillation during start-up. Then, two experiments carried out on a laboratory scale column were chosen to validate the model. Finally, a sensitivity study is presented observing composition response while changing the reflux strategy. The results show that the process can be improved by applying a high reflux ratio and establishing the hydraulics as soon as possible. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800962b

Validation of Dividing-Wall Columns Based on Experimental Data and Dynamic Simulations / Gerit Niggemann in Industrial & engineering chemistry research, Vol. 51 N° 2 (Janvier 2012) 

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