Group Contribution with Association Equation of State GCA-EoS

1 Group Contribution with Association Equation of State (GCA-EoS) 

There are three terms in the expression of the residual Helmholtz function in the Group Contribution Association equation of state, each one representing the contributions of different intermolecular forces (i), repulsive or free volume A (ii), attractive or dispersive and (iii), specific association forces The residual Helmholtz function in the Group Contribution Association equation of state is given by  

The free volume contribution follows the expression developed by Mansoori and Leland for mixtures of hard spheres  

The following generalized expression is assumed for the temperature dependence of the hard sphere diameter  

The attractive term in the evaluation of the Helmholtz energy is a group contribution version of a density-dependent NRTL expression, where interactions are considered to take place through the surfaces of characteristic functional groups rather than through the surfaces of the parent molecules so that  

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Pereda, S., Awan, J.A., Mohammadi, A.H. et al. 2009. Solubility of hydrocarbons in water Experimental measurements and modeling using a group contribution with association equation of state (GCA-EoS). Fluid Phase Equilib. 275 52-59. 

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