The Calculation of Equilibrium Concentrations of Organic Substances in Supercritical Fluids

The Peng-Robinson equation of state is used to construct a model of solubility of high-molecular hydrocarbons in supercritical fluids. The excess Gibbs energy of solution is used to estimate the coefficients in mixture rules. This approach enables one to self-consistently correct the coefficients in the mixture rules depending on the concentration of the solute, temperature and pressure. The calculation results are compared with the experimental data. The solubility of fatty acids in supercritical carbon dioxide is estimated.