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PVTx properties of the CO2-H2O and CO2-H2O-NaCl systems below 647 K: Assessment of experimental data and thermodynamic models
Chemical Geology, 238 (3-4): 249 - 267 (2007)
DOI: 10.1016/j.chemgeo.2006.11.011
Аннотация
Evaluation of CO2 sequestration in formation brine or in seawater needs highly accurate experimental data or models of pressure-volume-temperature-composition (PVTx) properties for the CO2-H2O and CO2-H2O-NaCl systems. This paper presents a comprehensive review of the experimental PVTx properties and the thermodynamic models of these two systems.
The following conclusions are drawn from the review:
(1) About two-thirds of experimental data are consistent with each other, where the uncertainty in liquid volumes is within 0.5\%, and that in gas volumes within 2\%. However, this accuracy is not sufficient for assessing CO2 sequestration. Among the data sets for liquids, only a few are available for accurate modeling of CO2 sequestration. These data have an error of about 0.1\% on average, roughly covering from 273 to 642 K and from 1 to 35 MPa;
(2) There is a shortage of volumetric data of saturated vapor phase.
(3) There are only a few data sets for the ternary liquids, and they are inconsistent with each other, where only a couple of data sets can be used to test a predictive density model for CO2 sequestration;
(4) Although there are a few models with accuracy close to that of experiments, none of them is accurate enough for CO2 sequestration modeling, which normally needs an accuracy of density better than 0.1\%. Some calculations are made available on www.geochem-model.org.
