High Pressure Phase Equilibrium of (Solvent + Salt + CO۲) Systems by the Extended Peng-Robinson Equation of State

An extended Peng-Robinson equation of state (EPR-EOS) is used to model the vapor-liquid equilibrium (VLE) in systems containing (water + NaCl + CO۲), (water + methanol + NaCl + CO۲), (water + Na۲SO۴ + CO۲) and (water + NH۴Cl + CO۲). The binary and ternary interaction parameters between salt and solvent are adjusted to experimental mean solvent activity of salts (NaCl and Na۲SO۴). For the system containing (water + Na۲SO۴ + CO۲), the EPR-EOS is used to predict the P-T diagram when the moles of Na۲SO۴ in ۱ kg water are ۰.۲۵, ۰.۵ and ۱. The calculated results for the (water + Na۲SO۴ + CO۲) system by the extended PR-EOS are compared with the correlation results by Anderko-Pitzer EOS. The average absolute deviation of (ΔP/Pexp) % between the correlation results by Anderko-Pitzer EOS and experimental data is ۸.۴ % while this value for extended PR-EOS is ۶ %. The P-x diagram for (water + NH۴Cl + supercritical-CO۲) system at temperatures (۳۳۳ and ۳۵۳ K) are also obtained and compared with the calculation results by VTPRLIFAC model. The average absolute deviation between calculation results by VTPRLIFAC model and experimental data is ۷.۸ % but this value for our calculations is ۶.۲ %.

کلیدواژه ها:

Vapor-liquid equilibrium (VLE) ، Peng-Robinson equation of state (PR-EOS) ، CO۲ ، Salt