Predicting phase behavior of metallic mercury in liquid and compressed gaseous hydrocarbons

This study presents the first predictive approach for estimating phase behavior of metallic mercury in hydrocarbons and compressed gases. This approach is based on the recently developed CP-PC-SAFT EoS attached by a universal value of k12 = 0.3. The CP method of solving SAFT parameters is not applicable for metallic mercury. Therefore it has been treated as a monoatomic substance, while σ and ε/k have been adjusted to the experimental vapor pressure and density data. It has been demonstrated that the proposed approach accurately predicts the solubility enhancement of metallic mercury in the compressed gases up to ∼400 bar. The solubility data in liquid n-alkanes, aromatic and oxygenated hydrocarbons in wide range of temperatures have been truthfully estimated as well. The available binary diffusion coefficients of mercury in gases can also be accurately predicted by the Chapman–Enskog model when applied with the model’s molecular parameters. This study also shows that the analogous implementation of the original version of PC-SAFT results in a slightly lesser over-all accuracy, which could probably be attributed to the not entirely systematic practice of evaluating its molecular parameters for various hydrocarbons. A doubtless advantage of both considered versions of PC-SAFT over Peng–Robinson EoS is demonstrated as well.