Development of a consistent cubic equation of state for the calculation of the phase behaviour and thermodynamic properties of pure components

Abstract

This study analyzes two cubic equations of state (CEoS), the Redlich-Kwong (RK) and PengRobinson (PR) CEoS, to calculate the properties of 151 pure components. The components were grouped by their intermolecular interactions (polar, non-polar, hydrogen bonding) and their saturation pressure (P sat), enthalpy of vaporization (∆Hv), and saturated liquid heat capacity (Cp sat) were calculated using a unique combination of the PR and RK CEoS paired with either the Twu or Soave α-functions. Outliers were eliminated using a quantile regression algorithm; additionally, a set of constraints proposed by Le Guennec et al.(Le Guennec et al. 2016) was applied to ensure that thermodynamic consistency was enforced during optimization. The four models tested were named PR-Twu, PR-Soave, RK-Twu, and RK-Soave, based on the equation of state and alpha function used. The PR-Twu and RK-Twu models predict P sat , ∆Hv, and Cp sat more accurately than the PR-Soave and RK-Soave models. [...]