Scaled equation of state for multi-component fluids

•Complete scaling concept was employed to develop EOS for near-critical fluid mixtures.•We used a 14-component gas mixture to represent a natural gas-condensate.•Adiabatic calorimeter was used to measure the gas-condensate mixture properties.•Proposed EOS allows to describe the obtained experimental data with high accuracy.•EOS enables us to calculate the dew-bubble curves and the mixture critical parameters.

Theory model based on the concept of so-called “complete scaling” has been extensively developed for multicomponent mixtures. As a result, the equation of state (EOS) for near-critical mixture with given composition has been formulated. To verify the validity of the obtained EOS, it was applied for the description of thermodynamic properties of the fourteen-component mixture modeling a natural gas condensate. The mixture has been studied in our laboratory by the adiabatic calorimetry method. The measurements of the pressure, the derivative (∂P/∂T)ρ,x and heat capacity Cρ,x were carried out for nine isochores in rather wide range of pressures and temperatures including the near-critical region. It has been demonstrated that the proposed EOS describes adequately the experimental data in one- and two-phase region of the mixture with the sufficiently high accuracy. In addition, the analysis of experimental data by means of developed EOS enables us to calculate the dew-bubble curves of the mixture as well as to determine the mixture critical parameters.

Graphical abstractDownload full-size image