Frenkel line and solubility maximum in supercritical fluids

Area of Science:

• Thermodynamics
• Physical Chemistry
• Fluid Dynamics

Background:

• The supercritical state is a distinct phase of matter.
• A new dynamic line, the Frenkel line, has been proposed to delineate regions within the supercritical state.
• The precise location and behavior of the Frenkel line for real fluids remain largely uncharacterized.

Purpose of the Study:

• To determine the location of the Frenkel line on the phase diagram for carbon dioxide (CO2), water (H2O), and methane (CH4).
• To investigate the physical significance of the Frenkel line as a separator of liquid-like and gas-like fluid properties.
• To explore the relationship between the Frenkel line and observed solubility phenomena.

Main Methods:

• Computational modeling and simulation techniques were employed.
• Phase diagram analysis was conducted for selected real fluid systems.
• Thermodynamic properties were analyzed to identify the Frenkel line's position.

Main Results:

• The Frenkel line was successfully mapped for CO2, H2O, and CH4.
• A distinct demarcation separating liquid-like and gas-like supercritical fluid behaviors was identified.
• The Frenkel line exhibits trends similar to the melting line above critical pressure.
• A correlation between the Frenkel line and solubility maxima was observed.

Conclusions:

• The Frenkel line provides a crucial demarcation for understanding supercritical fluid states.
• The findings suggest the Frenkel line represents optimal conditions for enhanced solubility.
• This research offers a new perspective on supercritical fluid behavior and its applications.