Documents disponibles écrits par cet auteur

Modeling of biodiesel multicomponent systems with the cubic-plus-association (CPA) equation of state / Mariana B. Oliveira in Industrial & engineering chemistry research, Vol. 49 N° 3 (Fevrier 2010)

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 3 (Fevrier 2010) . - pp. 1419–1427 Titre : Modeling of biodiesel multicomponent systems with the cubic-plus-association (CPA) equation of state Type de document : texte imprimé Auteurs : Mariana B. Oliveira, Auteur ; António J. Queimada, Auteur ; João A.P. Coutinho, Auteur Année de publication : 2010 Article en page(s) : pp. 1419–1427 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Modeling--Biodiesel--Multicomponent--Systems--Cubic-Plus-Association--(CPA)  Equation--State Résumé : To supply biodiesel with the quality levels required by the standards for alternative fuels, the separation and purification units are extremely important in the biodiesel production plants. The correct knowledge and description of the phase equilibria in systems composed by transesterification products is essential for a correct operation and optimization of the purification process. For that purpose, the cubic-plus-association equation of state (CPA EoS) was here applied to model the phase equilibria of multicomponent systems common to biodiesel production and purification processes. It is shown that the CPA EoS can provide a good description of the liquid−liquid equilibria of multicomponent mixtures containing alcohols, glycerol, and fatty acid esters in the temperature range of operation of the separation units in biodiesel plants. As the liquid−liquid phase equilibrium description depends on the EoS parameters, a discussion is also presented about the best set of parameters and the method to estimate them. ISSN : 0888-5885 [article] Modeling of biodiesel multicomponent systems with the cubic-plus-association (CPA) equation of state [texte imprimé] / Mariana B. Oliveira, Auteur ; António J. Queimada, Auteur ; João A.P. Coutinho, Auteur . - 2010 . - pp. 1419–1427. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 3 (Fevrier 2010) . - pp. 1419–1427 Mots-clés : Modeling--Biodiesel--Multicomponent--Systems--Cubic-Plus-Association--(CPA)  Equation--State Résumé : To supply biodiesel with the quality levels required by the standards for alternative fuels, the separation and purification units are extremely important in the biodiesel production plants. The correct knowledge and description of the phase equilibria in systems composed by transesterification products is essential for a correct operation and optimization of the purification process. For that purpose, the cubic-plus-association equation of state (CPA EoS) was here applied to model the phase equilibria of multicomponent systems common to biodiesel production and purification processes. It is shown that the CPA EoS can provide a good description of the liquid−liquid equilibria of multicomponent mixtures containing alcohols, glycerol, and fatty acid esters in the temperature range of operation of the separation units in biodiesel plants. As the liquid−liquid phase equilibrium description depends on the EoS parameters, a discussion is also presented about the best set of parameters and the method to estimate them. ISSN : 0888-5885

Phase equilibria of ester + alcohol systems and their description with the cubic-plus-association equation of state / Mariana B. Oliveira 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. 3452–3458 Titre : Phase equilibria of ester + alcohol systems and their description with the cubic-plus-association equation of state Type de document : texte imprimé Auteurs : Mariana B. Oliveira, Auteur ; Sofia I. Miguel, Auteur ; António J. Queimada, Auteur Année de publication : 2010 Article en page(s) : pp. 3452–3458 Note générale : Industrial Chemistry Langues : Anglais (eng) Mots-clés : Equilibria  Ester  Alcohol  Cubic-Plus Résumé : The knowledge and the capability to describe the phase equilibria of binary systems formed by a fatty acid ester and an alcohol are of great interest in biodiesel production, where these mixtures can be found after the transesterification unit and where they must be separated to purify the biodiesel stream and to recover the unreacted alcohol. Despite this interest, little information is available on the vapor−liquid equilibria (VLE) of fatty acid ester + alcohol systems. To overcome this lack of data, new VLE measurements of six ester + methanol/ethanol systems were carried at atmospheric pressure. This new experimental data was successfully modeled with the Cubic-Plus-Association equation of state (CPA EoS), with global average deviations of 0.5% for the bubble-point temperatures. In all cases small and temperature independent parameters were enough to adequately describe the measured data. Furthermore a constant value for the cross-association energy parameter was proposed for each alcohol system, as well as a linear correlation for the binary interaction parameter with the ester chain length, making the CPA EoS a powerful predictive model for these systems. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901470s [article] Phase equilibria of ester + alcohol systems and their description with the cubic-plus-association equation of state [texte imprimé] / Mariana B. Oliveira, Auteur ; Sofia I. Miguel, Auteur ; António J. Queimada, Auteur . - 2010 . - pp. 3452–3458. Industrial Chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 7 (Avril 2010) . - pp. 3452–3458 Mots-clés : Equilibria  Ester  Alcohol  Cubic-Plus Résumé : The knowledge and the capability to describe the phase equilibria of binary systems formed by a fatty acid ester and an alcohol are of great interest in biodiesel production, where these mixtures can be found after the transesterification unit and where they must be separated to purify the biodiesel stream and to recover the unreacted alcohol. Despite this interest, little information is available on the vapor−liquid equilibria (VLE) of fatty acid ester + alcohol systems. To overcome this lack of data, new VLE measurements of six ester + methanol/ethanol systems were carried at atmospheric pressure. This new experimental data was successfully modeled with the Cubic-Plus-Association equation of state (CPA EoS), with global average deviations of 0.5% for the bubble-point temperatures. In all cases small and temperature independent parameters were enough to adequately describe the measured data. Furthermore a constant value for the cross-association energy parameter was proposed for each alcohol system, as well as a linear correlation for the binary interaction parameter with the ester chain length, making the CPA EoS a powerful predictive model for these systems. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901470s

Thermodynamic modeling of the aqueous solubility of PAHs / Mariana B. Oliveira 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. 5530–5536 Titre : Thermodynamic modeling of the aqueous solubility of PAHs Type de document : texte imprimé Auteurs : Mariana B. Oliveira, Auteur ; Vera L. Oliveira, Auteur ; João A.P. Coutinho, Auteur Année de publication : 2009 Article en page(s) : pp. 5530–5536 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Polycyclic  aromatic  hydrocarbons  Aqueous  solubilities  CPA  EoS Résumé : Polycyclic aromatic hydrocarbons (PAHs) are a family of compounds characterized by having two or more condensed aromatic rings. They are important environmental contaminants associated with oil spills and the incomplete combustion of organic materials. Different models are available in the literature for estimating the aqueous solubilities of organic compounds, but the most accurate are frequently based on the correlation of experimental data, which hampers their use as predictive tools. In this work, the cubic-plus-association equation of state (CPA EoS) is shown to be an accurate model for describing the aqueous solubilities of several solid PAHs in wide temperature and pressure ranges. The results obtained are in very close agreement with the literature data, even when the model is used in a totally predictive scheme. Following previous results on the aqueous solubilities of other organic pollutants, the use of the CPA EoS for describing the aqueous solubilities of organic pollutants such as polycyclic aromatic hydrocarbons is suggested. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900011g [article] Thermodynamic modeling of the aqueous solubility of PAHs [texte imprimé] / Mariana B. Oliveira, Auteur ; Vera L. Oliveira, Auteur ; João A.P. Coutinho, Auteur . - 2009 . - pp. 5530–5536. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5530–5536 Mots-clés : Polycyclic  aromatic  hydrocarbons  Aqueous  solubilities  CPA  EoS Résumé : Polycyclic aromatic hydrocarbons (PAHs) are a family of compounds characterized by having two or more condensed aromatic rings. They are important environmental contaminants associated with oil spills and the incomplete combustion of organic materials. Different models are available in the literature for estimating the aqueous solubilities of organic compounds, but the most accurate are frequently based on the correlation of experimental data, which hampers their use as predictive tools. In this work, the cubic-plus-association equation of state (CPA EoS) is shown to be an accurate model for describing the aqueous solubilities of several solid PAHs in wide temperature and pressure ranges. The results obtained are in very close agreement with the literature data, even when the model is used in a totally predictive scheme. Following previous results on the aqueous solubilities of other organic pollutants, the use of the CPA EoS for describing the aqueous solubilities of organic pollutants such as polycyclic aromatic hydrocarbons is suggested. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900011g