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Title: Structural Evolution of Supercritical CO2 across the Frenkel Line

Authors:
; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL)
Sponsoring Org.:
USDOE SC OFFICE OF SCIENCE (SC)
OSTI Identifier:
1162907
Report Number(s):
BNL-106853-2014-JA
Journal ID: ISSN 1948--7185
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: The Journal of Physical Chemistry Letters; Journal Volume: 5; Journal Issue: 16
Country of Publication:
United States
Language:
English

Citation Formats

Bolmatov, D., Zavyalov, D., Gao, M., and Zhernenkov, M. Structural Evolution of Supercritical CO2 across the Frenkel Line. United States: N. p., 2014. Web. doi:10.1021/jz5012127.
Bolmatov, D., Zavyalov, D., Gao, M., & Zhernenkov, M. Structural Evolution of Supercritical CO2 across the Frenkel Line. United States. doi:10.1021/jz5012127.
Bolmatov, D., Zavyalov, D., Gao, M., and Zhernenkov, M. Tue . "Structural Evolution of Supercritical CO2 across the Frenkel Line". United States. doi:10.1021/jz5012127.
@article{osti_1162907,
title = {Structural Evolution of Supercritical CO2 across the Frenkel Line},
author = {Bolmatov, D. and Zavyalov, D. and Gao, M. and Zhernenkov, M},
abstractNote = {},
doi = {10.1021/jz5012127},
journal = {The Journal of Physical Chemistry Letters},
number = 16,
volume = 5,
place = {United States},
year = {Tue Jul 29 00:00:00 EDT 2014},
month = {Tue Jul 29 00:00:00 EDT 2014}
}
  • Cited by 4
  • Phase equilibria in mixtures containing carbon dioxide, water, and chloride salts have been investigated using a combination of solubility measurements and thermodynamic modeling. The solubility of water in the CO2-rich phase of ternary mixtures of CO2, H2O and NaCl or CaCl2 was determined, using near infrared spectroscopy, at 90 atm and 40 to 100 °C. These measurements fill a gap in the experimental database for CO2 water salt systems, for which phase composition data have been available only for the H2O-rich phases. A thermodynamic model for CO2 water salt systems has been constructed on the basis of the previously developedmore » Mixed-Solvent Electrolyte (MSE) framework, which is capable of modeling aqueous solutions over broad ranges of temperature and pressure, is valid to high electrolyte concentrations, treats mixed-phase systems (with both scCO2 and water present) and can predict the thermodynamic properties of dry and partially water-saturated supercritical CO2 over broad ranges of temperature and pressure. Within the MSE framework the standard-state properties are calculated from the Helgeson-Kirkham-Flowers equation of state whereas the excess Gibbs energy includes a long-range electrostatic interaction term expressed by a Pitzer-Debye-Hückel equation, a virial coefficient-type term for interactions between ions and a short-range term for interactions involving neutral molecules. The parameters of the MSE model have been evaluated using literature data for both the H2O-rich and CO2-rich phases in the CO2 - H2O binary and for the H2O-rich phase in the CO2 - H2O - NaCl / KCl / CaCl2 / MgCl2 ternary and multicompontent systems. The model accurately represents the properties of these systems at temperatures from 0°C to 300 °C and pressures up to ~4000 atm. Further, the solubilities of H2O in CO2-rich phases that are predicted by the model are in agreement with the new measurements for the CO2 - H2O - NaCl and CO2 - H2O - CaCl2 systems. Thus, the model can be used to predict the effect of various salts on the water content and water activity in CO2-rich phases on the basis of parameters determined from the properties of aqueous systems. Given the importance of water activity in CO2-rich phases for mineral reactivity, the model can be used as a foundation for predicting mineral transformations across the entire CO2/H2O composition range from aqueous solution to anhydrous scCO2. An example application using the model is presented which involves the transformation of forsterite to nesquehonite as a function of temperature and water content in the CO2-rich phase.« less