On the linear approximation of mixture internal energies of departure

Direct Monte Carlo simulation of internal energies of departure for binary mixtures of geological interest are gathered and compared to those calculated using a linear mixing rule. Simulation results for gas–oil, oil–oil, and oil–water mixtures show that the linear mixing rule used in the Gibbs–Helmholtz Constrained (GHC) equation of state framework gives accurate approximations of binary mixture internal energies of departure. A flowchart for computing internal energies of departure using Monte Carlo simeywords: nternal energy of departure irect Monte Carlo simulation inear mixing rule eological binary mixtures ulation is included along with a sensitivity analysis for the GHC mixture energy parameter with respect to uncertainty in internal energies of departure. © 2015 Elsevier Ltd. All rights reserved. HC equation of state . Introduction The Gibbs–Helmholtz Constrained (GHC) equation of state (EOS) s a multi-scale adaptation of the Soave form (Soave, 1972) of the edlich–Kwong EOS (Redlich and Kwong, 1949), = RT V − b − a V(V + b) (1) here the energy parameter, a, given by (T, P) = [ 0.42748RTc Pc + bU D Tc ln 2 + 2bR ln Tc ln 2 ] T − bU D ln 2 − [ 2bR ln 2 ] T ln T (2) s derived analytically by constraining a(T,P) to satisfy the ibbs–Helmholtz equation ∂ ln φ ∂T )