A New Three Parameter Cubic Equation of State


Department of Chemistry,Kuwait University


A new three parameter Equation Of State (EOS) is developed based on well documented
data, at three thermodynamic states of the critical point, the normal bubble point and standard condition.
Besides these states, the EOS is designed to satisfy the condition of nearly zero Joule-Thomson (JT)
coecients at the normal boiling point. Critical properties and densities at the normal boiling point
and a standard condition of more than 100 pure
uids were used. The new EOS is validated using
experimental data and eight (8) of the popular EOSs, namely, SRK, PR, LLS, HK, MNM, SW, PT and
ALS. The experimental data for pure
uids include 331 data points of vapor pressure covering 12
and compressibility at the critical condition of 23
uids. For mixtures, the data includes 129 PVT data
points of 12 reservoir
uids [seven (7) of them are Sudanese crude oil considered for publication for the
rst time and ve (5) from literature]. The new EOS is found to be superior to the existing EOSs in
the prediction of PVT properties of mixtures with a grand average percent absolute deviation (AAPD) of
3.18%. It is also comparable to the existing EOSs in the prediction of vapor pressure despite the fact that
existing EOSs are developed based on vapor pressure data; the grand average AAPD is 2.0. In terms of
compressibility at the critical point with the exception of LLS, the new EOS yields better results than all
other EOSs considered in this work.