Conference paper · Journal article
Modeling phase equilibria for acid gas mixtures using the CPA equation of state. Part II: Binary mixtures with CO2
CERE – Center for Energy Ressources Engineering, Department of Chemical and Biochemical Engineering, Technical University of Denmark1
Department of Chemical and Biochemical Engineering, Technical University of Denmark2
Department of Chemistry, Technical University of Denmark3
Center for Energy Resources Engineering, Centers, Technical University of Denmark4
In Part I of this series of articles, the study of H2S mixtures has been presented with CPA. In this study the phase behavior of CO2 containing mixtures is modeled. Binary mixtures with water, alcohols, glycols and hydrocarbons are investigated. Both phase equilibria (vapor–liquid and liquid–liquid) and densities are considered for the mixtures involved.
Different approaches for modeling pure CO2 and mixtures are compared. CO2 is modeled as non self-associating fluid, or as self-associating component having two, three and four association sites. Moreover, when mixtures of CO2 with polar compounds (water, alcohols and glycols) are considered, the importance of cross-association is investigated.
The cross-association is accounted for either via combining rules or using a cross-solvation energy obtained from experimental spectroscopic or calorimetric data or from ab initio calculations. In both cases two adjustable parameters are used when solvation is explicitly accounted for. The performance of CPA using the various modeling approaches for CO2 and its interactions is presented and discussed, comparatively to various recent published investigations.
It is shown that overall very good correlation is obtained for binary mixtures of CO2 and water or alcohols when the solvation between CO2 and the polar compound is explicitly accounted for, whereas the model is less satisfactory when CO2 is treated as self-associating compound.
Language: | English |
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Year: | 2011 |
Pages: | 38-56 |
Proceedings: | 20 Years of the SAFT Equation of State |
ISSN: | 18790224 and 03783812 |
Types: | Conference paper and Journal article |
DOI: | 10.1016/j.fluid.2011.02.006 |
ORCIDs: | Kontogeorgis, Georgios and Stenby, Erling Halfdan |