Volume translation in equations of state as a means of accurate property estimation

Molar volumes predicted by cubic volumetric equations of state (EOS)s over a range of reduced temperatures and pressures from Tr = 0.5–2.0 and Pr = 0.5–10.0 were compared to reference molar volume values for water, carbon dioxide, hydrogen sulfide, ammonia, nitrogen, oxygen, argon, and the first eight normal paraffin alkanes. A similarity of molar volume residuals was observed for predictions by the Soave–Redlich–Kwong EOS, indicating that volume translation can be used to improve the accuracy of these molar volume predictions. The necessity of both density and temperature dependence in the volume translation is established; guidelines for maintaining thermodynamic consistency and a correlation for identifying the maxima in molar volume residuals are provided.