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Modelling of phase equilibria for associating mixtures using an equation of state
Ferreira, Olga; Brignole, Esteban A.; Macedo, Maria E.In the present work, the group contribution with association equation of state (GCA-EoS) is extended to represent phase equilibria in mixtures containing acids, esters, and ketones, with water, alcohols, and any number of inert components. Association effects are represented by a group-contribution approach. Self- and cross-association between the associating groups present in these mixtures are considered. The...
Phase equilibria in sugar solutions using the A-UNIFAC model
Ferreira, Olga; Brignole, Esteban A.; Macedo, Maria E.http://apps.isiknowledge.com/full_record.do?product=UA&search_mode=GeneralSearch&qid=2&SID=V21Di6PajaHLPoM3@AJ&page=1&doc=1&colname=WOS ; In this work, a modified UNIFAC model that explicitly takes into account association effects is used to describe the thermodynamic properties of phase equilibria of mixtures containing common sugars, alcohols, and water. Three main groups were defined to represent the sugars...
Modeling of association effects in mixtures of carboxylic acids with associatin...
Ferreira, Olga; Fornari, Tiziana; Brignole, Esteban A.; Bottini, Susana B.http://apps.isiknowledge.com/full_record.do?product=UA&search_mode=GeneralSearch&qid=6&SID=V21Di6PajaHLPoM3@AJ&page=1&doc=1&colname=WOS ; The group contribution with association equation of state GCA-EOS has been applied to calculate thermodynamic properties of pure compounds and mixtures of carboxylic acids with paraffins, alcohols, water and gases, at low and high pressures. Two associating groups, OH and CO...
Application of the GCA-EOS model to the supercritical processing of associating...
Ferreira, Olga; Pereda, Selva; Bottini, Susana B.; Brignole, Esteban A.Supercritical processes are of interest in the fatty oil industry for a variety of applications: extraction and refining, removal of pollutants, recovery of specialties, hydrogenation of oils and derivatives, etc. Typical process mixtures include heavy compounds and gases at near critical conditions. At high pressures these asymmetric systems present a complex multiphase behaviour, difficult to model. This com...
Extension of UNIFAC to associating systems
Foco, Gloria; Ferreira, Olga; Brignole, Esteban A.; Bottini, Susana B.An extended UNIFAC group contribution model for the prediction of activity coefficients in associating mixtures was presented recently (Mengarelli et al.,1999). In the present work the model is applied to solutions containing alcohols, water, carboxylic acids and inert components. The residual UNIFAC local composition term is re-parameterized in order to take into account only dispersive forces between associat...
A general group contribution model for activity coefficients in associating sol...
Ferreira, Olga; Brignole, Esteban A.; Bottini, Susana B.; Macedo, Eugénia A.A modifed UNIFAC group contribution model for the prediction of activity coefficients in associating mixtures was proposed recently (Mengarelli et al., 1999). In the present work, the model is extended to carboxylic acids by defining a general associating group which allows a straightforward extension to multicomponent mixtures. The residual UNIFAC local composition term is re-parameterized in order to take int...
The extended gca-eos model for mixtures of fatty oils and derivatives
Ferreira, Olga; Fornari, Tiziana; Brignole, Esteban A.; Bottini, Susana B.The Group Contribution Equation of State GC-EOS has been satisfactory applied to the modeling of high-pressure phase equilibria of supercritical gases (CO2, propane, ethane, dimethylether) with pure triglycerides and natural vegetable oils. The GC-EOS model size-related parameter, i.e. the critical hard sphere diameter, of the high molecular weight compounds were determined by fitting infinite dilution activity...
A group contribution model for activity coefficients in associating solutions
Ferreira, Olga; Brignole, Esteban A.; Bottini, Susana B.A group contribution model is presented for the prediction of activity coefficients in associating mixtures. The new model adds an association term to the traditional UNIFAC residual and combinatorial contributions to the activity coefficients. The association term is based on Wertheim’s theory for fluids with highly directed attractive forces, as applied in the SAFT equation, and it follows the group contribut...
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