Consistent Twu parameters for more than 2300 pure fluids from critically evaluated experimental data

Published

February 26, 2018

Author(s)

Ian H. Bell, Marco Satyro, Eric W. Lemmon

Abstract

Standard cubic equations of state like Peng-Robinson or SRK do not, by their construction, yield physically reasonable values by default when the equation of state is extrapolated beyond the range where experimental data are available. A multi-property fitting exercise was carried out in which we obtained a consistent set of Twu $\alpha$ function parameters for 2345 pure fluids according to the experimental data contained in the ThermoDataEngine (TDE) database developed at NIST. We have applied the consistency checks of Le Guennec et al. to the Twu \alpha function of the Peng-Robinson equation of state. The experimental data stored in TDE passed through a consistency screening, and we used only the data that were determined to be thermodynamically consistent. Over all the considered fluids, the mean average absolute error is approximately 2% for both vapor pressure and latent heat. The obtained parameters should be considered as the new reference set of Twu parameters for industrial applications of cubic equations of state.

Citation

Journal of Chemical and Engineering Data

Pub Type

Journals

Download Paper

https://doi.org/10.1021/acs.jced.7b00967

Citation

Bell, I. , Satyro, M. and Lemmon, E. (2018), Consistent Twu parameters for more than 2300 pure fluids from critically evaluated experimental data, Journal of Chemical and Engineering Data, [online], https://doi.org/10.1021/acs.jced.7b00967 (Accessed October 11, 2025)