Simplified Gas State Equations at Saturation and Isotherm

Area of Science:

• Thermodynamics
• Physical Chemistry
• Chemical Engineering

Background:

• Existing gas state equations (EOS) require simplification for broader applicability.
• Understanding gas-liquid phase transitions and solubility is crucial in various scientific and industrial fields.

Purpose of the Study:

• To simplify the gas state equation (EOS) by introducing a novel thermodynamic constant, P*c.
• To verify Henry's law of gas solubility using the proposed simplified EOS.
• To explore the applicability of the modified EOS across a wide pressure and temperature range, including supercritical states.

Main Methods:

• Introduction of a theoretical pressure constant, P*c, representing the pressure at which gas converts to liquid.
• Linear regression analysis of ln P-ln x2 in gas-liquid saturation systems.
• Derivation of the isothermal EOS by differentiating heat over VG.
• Demonstration of the EOS using Argon (Ar) as an example across 0-1000 MPa.

Main Results:

• The simplified EOS successfully verifies Henry's law.
• P*c values for most substances fall within the range of 15-16 (3.269-8.886 MPa).
• The modified EOS shows promising results in the pre-gas-liquid transition pressure range and at high temperatures (1000-2000 K).
• The supercritical state at intermediate temperatures (160-800 K) exhibits liquid-like behavior, indicating limitations of the current EOS in this regime.

Conclusions:

• The simplified gas state equation offers a new perspective on gas behavior and gas solubility.
• The study highlights the distinct characteristics of the supercritical state at intermediate temperatures.
• Further refinement of the EOS may be necessary for accurately describing all states of matter, particularly the intermediate supercritical region.