Premium
The density characteristics of CO 2 and alkane mixtures using PC‐SAFT EoS
Author(s) -
Chi Yuan,
Liu Shuyang,
Jian Weiwei,
Zhao Changzhong,
Lv Junchen,
Zhang Yi
Publication year - 2020
Publication title -
greenhouse gases: science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.45
H-Index - 32
ISSN - 2152-3878
DOI - 10.1002/ghg.2026
Subject(s) - alkane , hexadecane , thermodynamics , heptane , chemistry , equation of state , carbon number , hydrocarbon , organic chemistry , physics , alkyl
Abstract The density of CO 2 + crude oil mixtures is one of the most important parameters influencing CO 2 diffusion and migration in oil reservoirs. However, it would be quite time consuming to obtain comprehensive density data for CO 2 + alkane mixtures over a wide range of temperatures and pressures via experimental methods, therefore the development of a reliable model for predicting the densities of various CO 2 + alkane mixtures with high accuracy is crucial. In this paper, the parameters ( m , σ , and ε/k ) in the perturbed‐chain statistical associating fluid theory (PC‐SAFT) Equation of State (EoS) were optimized by correlating density data of pure n‐alkanes from heptane to nonadecane (except undecane and hexadecane). For comparison, the G‐S PC‐SAFT and HTHP PC‐SAFT EoS(s) were also employed to fit the densities of these n‐alkanes, and the results demonstrated that the PC‐SAFT EoS with the optimized parameters in this study exhibited superior accuracy. Subsequently, by correlating density data of CO 2 + alkane mixtures containing C7–C14 alkanes, the binary interaction parameter k ij was optimized. Furthermore, for the first time, correlations between the optimized parameters ( m , σ , ε / k , and k ij ) and alkane carbon number ( n ) were established. These correlations provided PC‐SAFT EoS with a good universality and scalability for density prediction. Using the parameters calculated from these correlations, the densities of hexadecane and saturated CO 2 + alkane mixtures containing C10–C20 alkanes were successfully predicted with relatively high accuracy. This work provides a new way for modeling the thermodynamic properties of CO 2 + alkane mixtures. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd.