A perturbed hard-sphere chain equation of state: prediction from boiling point constants

Abstract

A modified perturbed hard-sphere chain equation of state (EOS) is developed to predict the PVT (pressure, volume, temperature) properties of fluids simply and accurately. Two temperature-dependent parameters, an effective van der Waals covolume and the strength of the attractive forces between two non-bonded segments, appear in this equation. Due to the law of corresponding states, we have correlated these two parameters with very good accuracy. This is done by using the boiling point constants of fluids as scaling constants. Just one adjustable parameter remains, which can be calculated by fitting to a few experimental data. The predicted EOS is tested against the experimental data for a large number of fluids including a number of diatomic and polyatomic inorganic molecules, saturated and compressed hydrocarbons, and a number of olefins and aromatics. The agreement with experiment is very good and within 2%.

Keywords:

• hard-sphere chain equation of state
• law of corresponding states
• boiling point properties

Acknowledgement

The support of Research Committee of Persian Gulf University and Ahvaz Azad University, Science and Research, is greatly acknowledged.