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Approach to Improve Speed of Sound Calculation within PC-SAFT Framework / Xiaodong Liang in Industrial & engineering chemistry research, Vol. 51 N° 45 (Novembre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 45 (Novembre 2012) . - pp. 14903–14914 Titre : Approach to Improve Speed of Sound Calculation within PC-SAFT Framework Type de document : texte imprimé Auteurs : Xiaodong Liang, Auteur ; Bjorn Maribo-Mogensen, Auteur ; Kaj Thomsen, Auteur Année de publication : 2013 Article en page(s) : pp. 14903–14914 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Speed  sound  data  parameter  estimation Résumé : An extensive comparison of SRK, CPA, and PC-SAFT for the speed of sound in normal alkanes has been performed. The results reveal that PC-SAFT captures the curvature of the speed of sound better than cubic EoS, but the accuracy is not satisfactory. Two approaches have been proposed to improve PC-SAFT’s accuracy for speed of sound: (i) putting speed of sound data into parameter estimation; (ii) putting speed of sound data into both universal constants regression and parameter estimation. The results have shown that the second approach can significantly improve the speed of sound (3.2%) prediction while keeping acceptable accuracy for the primary properties, i.e. vapor pressure (2.1%) and liquid density (1.5%). The two approaches have also been applied to methanol, and both give very good results. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3018127 [article] Approach to Improve Speed of Sound Calculation within PC-SAFT Framework [texte imprimé] / Xiaodong Liang, Auteur ; Bjorn Maribo-Mogensen, Auteur ; Kaj Thomsen, Auteur . - 2013 . - pp. 14903–14914. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 45 (Novembre 2012) . - pp. 14903–14914 Mots-clés : Speed  sound  data  parameter  estimation Résumé : An extensive comparison of SRK, CPA, and PC-SAFT for the speed of sound in normal alkanes has been performed. The results reveal that PC-SAFT captures the curvature of the speed of sound better than cubic EoS, but the accuracy is not satisfactory. Two approaches have been proposed to improve PC-SAFT’s accuracy for speed of sound: (i) putting speed of sound data into parameter estimation; (ii) putting speed of sound data into both universal constants regression and parameter estimation. The results have shown that the second approach can significantly improve the speed of sound (3.2%) prediction while keeping acceptable accuracy for the primary properties, i.e. vapor pressure (2.1%) and liquid density (1.5%). The two approaches have also been applied to methanol, and both give very good results. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3018127

Comparison of the debye – hückel and the mean spherical approximation theories for electrolyte solutions / Bjorn Maribo-Mogensen in Industrial & engineering chemistry research, Vol. 51 N° 14 (Avril 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 14 (Avril 2012) . - pp. 5353-5363 Titre : Comparison of the debye – hückel and the mean spherical approximation theories for electrolyte solutions Type de document : texte imprimé Auteurs : Bjorn Maribo-Mogensen, Auteur ; Georgios M. Kontogeorgis, Auteur ; Kaj Thomsen, Auteur Année de publication : 2012 Article en page(s) : pp. 5353-5363 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Electrolyte  solution  Approximation Résumé : The thermodynamics of electrolyte solutions has been investigated by many scientists throughout the last century. While several theories have been presented, the most popular models for the electrostatic interactions are based on the Debye-Hückel and mean spherical approximation (MSA) theories. In this paper we investigate the differences between the Debye-Hückel and the MSA theories, and comparisons of the numerical results for the Helmholtz energy and its derivatives with respect to temperature, volume and composition are presented. The investigation shows that the nonrestricted primitive MSA theory performs similarly to Debye―Hückel, despite the differences in the derivation. We furthermore show that the static permittivity is a key parameter for both models and that in many cases it completely dominates the results obtained from the two models. Consequently, we conclude that the simpler Debye―Hückel theory may be used in connection with electrolyte equations of state without loss of accuracy. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25783445 [article] Comparison of the debye – hückel and the mean spherical approximation theories for electrolyte solutions [texte imprimé] / Bjorn Maribo-Mogensen, Auteur ; Georgios M. Kontogeorgis, Auteur ; Kaj Thomsen, Auteur . - 2012 . - pp. 5353-5363. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 14 (Avril 2012) . - pp. 5353-5363 Mots-clés : Electrolyte  solution  Approximation Résumé : The thermodynamics of electrolyte solutions has been investigated by many scientists throughout the last century. While several theories have been presented, the most popular models for the electrostatic interactions are based on the Debye-Hückel and mean spherical approximation (MSA) theories. In this paper we investigate the differences between the Debye-Hückel and the MSA theories, and comparisons of the numerical results for the Helmholtz energy and its derivatives with respect to temperature, volume and composition are presented. The investigation shows that the nonrestricted primitive MSA theory performs similarly to Debye―Hückel, despite the differences in the derivation. We furthermore show that the static permittivity is a key parameter for both models and that in many cases it completely dominates the results obtained from the two models. Consequently, we conclude that the simpler Debye―Hückel theory may be used in connection with electrolyte equations of state without loss of accuracy. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25783445