A modified differential-model for interaction parameters in PR EoS with vdW mixing rules for mixtures containing HFCs and HCs

In a previous work, a predictive model for the interaction parameter kij was proposed as kij = ki − kj. The assumed mixing factor ki for the pure components can be obtained by fitting to the correlated kij of mixtures which have available experimental data. In this work, up to 62 binary mixtures containing HFCs and HCs were involved and their reported experimental VLE data were correlated using the PR equation of state with the vdW mixing rules. According to the correlation results, a modified differential-model was proposed for the prediction of the interaction parameter kij with the introduction of the acentric factors and the critical properties of the components. The values of mixing factors ki in the modified model were obtained by the least square fitting of the correlated 62 kij data for 15 HFCs and HCs, namely HFC23, HFC32, HFC125, HFC143a, HFC134a, HFC134, HFC152a, HFC161, HFC227ea, HFC236fa, HFC236ea, HFC245fa, propane, isobutane, and n-butane. 105 predicted kij for mixtures containing these HFCs and HCs were given. The predicted results by using the modified model show a good agreement compared to the correlation results. The overall average absolute deviations of pressures and vapor phase compositions of the predicted results are 1.77% and 0.0086, respectively.

► VLE data of 62 mixtures containing HFCs and HCs were correlated using PR-vdW model.
► A modified difference-model was presented for the interaction parameter.
► Mixing factors ki in the model were given for 15 components.
► 105 predicted kij for mixtures containing HFCs and HCs were given.