Modeling the Viscosity for (nC5+nC8), (nC5+nC10), (nC8+nC10) and (nC5+nC8+nC10) Systems with Peng-Robinson Viscosity Equation of State

The aim of this modeling study is to improve the performance of the Peng-Robinson viscosity equation of state. To achieve this aim, the couple of Peng-Robinson viscosity equation of state and the proposed mixing rules has been applied for modeling the viscosities of the binary and ternary systems containing (nC5+nC8), (nC5+nC10), (nC8+nC10) and (nC5+nC8+nC10) for temperatures and pressures ranged (297.75-373.35) K and (49.95-246.26) bar, respectively. First, the pressure temperature-dependent and constant expressions for the binary interaction coefficients of binary systems have been determined. Subsequently, these empirical correlations of binary interaction coefficients have been applied to predict the viscosities for ternary mixture of (nC5+nC8+nC10 ). For this ternary mixture, the results of model show acceptable accuracy (overall AAD~7.77 % and 8.02 for mixing rule 1 and 2, respectively)

Using a New Proposed Influence Parameter of Gradient Theory for CH4/n-alkane Binary Systems: What Advances Can Be Achieved?

The main aim of this modeling investigation is to improve the performance of the gradient theory for binary systems of methane and n-alkane. To achieve this aim, the gradient theory (GT) is combined with the volume-translated Peng-Robinson equation of state (VTPR EOS) for accurate description of phase equilibrium and surface tensions of methane/hydrocarbon systems. To improve the phase equilibrium calculations, the binary interaction parameters of VTPR EOS for methane/hydrocarbon systems have been determined based on the mole fraction of methane in liquid phase. A new correlation of the influence parameter based on the densities of bulk phases has been suggested. To make the present model predictive, the binary interaction parameters of the mixture influence parameter have been set equal to zero. The results of the model show that the predictions of the present model agree well with experimental surface tensions, especially for very low values of surface tensions (near-critical interfaces)