VLE predictions with the Peng–Robinson equation of state and temperature dependent kij calculated through a group contribution method

Prediction of vapor-liquid equilibrium with the LCVM model : a linear combination of the Vidal and Michelsen mixing rules coupled with the original UNIFAC and the t-mPR equation of state

Applications of the simplified perturbed-chain SAFT equation of state using an extended parameter table

The knowledge of the solubility behavior of different lipid classes in supercritical carbon dioxide (SCCO2) is of great importance in the design of SCCO2 fractionation, extraction, and reaction processes. Solubility data from the literature for binary mixtures of SCCO2 and pure lipids (fatty acids, mono-, di-, and triglycerides, and fatty acid esters) were correlated using Chrastil's equation to determine the effect of compound properties (molecular weight and polarity) and operating conditions (density of CO2, pressure, and temperature) on the solubility behavior. The physical state of the lipid solute had a significant effect on model parameters and, hence, the solubility behavior. An isothermal increase in the pressure and a temperature increase at constant CO2 density led to an increase in solubility for all the compounds studied. Retrograde solubility behavior was observed for liquid solutes, whereas the solid solutes were in the nonretrograde region under the examined conditions. In a homologous ser...

Correlating the Solubility Behavior of Fatty Acids, Mono-, Di-, and Triglycerides, and Fatty Acid Esters in Supercritical Carbon Dioxide

A mixing rule for cubic equations of state (CEoS) applicable to all types of system asymmetriesreferred to hereafter as the universal mixing rule (UMR)is proposed For the cohesion parameter of the CEoS, the mixing rule involves the Staverman−Guggenheim part of the combinatorial term and the residual term of the original UNIFAC Gibbs free energy expression For the covolume parameter of the CEoS, the quadratic concentration-dependent mixing rule is used with the combining rule for the cross parameter bij = [1/2(bi1/2 + bj1/2)]2 This UMR is applied to the volume-translated and modified version of the Peng−Robinson equation of state of Magoulas and Tassios (Fluid Phase Equilib 1990, 56, 119), leading to what is referred to as the UMR−PR model Very satisfactory results are obtained using the existing interaction parameters of the original UNIFAC model for vapor−liquid equilibrium predictions at low and high pressures for a wide range of system asymmetries including mixtures containing polymers Satisfacto

Universal Mixing Rule for Cubic Equations of State Applicable to Symmetric and Asymmetric Systems: Results with the Peng−Robinson Equation of State

The authors present solubility data obtained for ethane in the heavy normal paraffin solvents n-eicosane, n-octacosane, n-hexatriacontane, and n-tetratetracontane. Measurements were made over the temperature range from 348 to 423{Kappa} (167-302 {sup 0}F) at pressures up to 7.8 MPa (1127 psia). The data can be described with average deviations of less than 0.003 mole fraction by the Soave-Redlich-Kwong or Peng-Robinson equation when two interaction parameters per isotherm are used in the equation.

Solubilities of ethane in heavy normal paraffins at pressures to 7.8 MPa and temperatures from 348 to 423 K

Solubility data are presented for ethane in n-hexane at temperatures from 311 to 394 K (100 to 250{sup 0}F) at pressures to 5.4 MPa (780 psia). These data are in significant disagreement with earlier measurements. The new data can be described with average deviations of less than 0.001 mole fraction by the Soave-Redlich-Kwong or Peng-Robinson equations when two interaction parameters per isotherm are used in the equation.

Aaron M. Raff

Papers

Solubilities of ethane in heavy normal paraffins at pressures to 7.8 MPa and temperatures from 348 to 423 K

Solubility of ethane in n-hexane at pressures to 5.4 MPa and temperatures from 311 to 394 K