The partial molar volumes for water dissolved in high-pressure carbon dioxide from T = (318.28 to 369.40) K and pressures to p = 35 MPa. (February 2016)

• Record Type: Journal Article
• Authors: Deering, Connor E.; Cairns, Edward C.; McIsaac, Jay D.; Read, Andrew S.; Marriott, Robert A.
• Is Part Of: Journal of chemical thermodynamics. Volume 93(2016:Feb.)
• Page Start: 337
• Page End: 346
• Publication Date: 2016-02
• Subjects: Wet carbon dioxide injection -- Density -- Molar volumes -- Krichevskii -- Reduced Helhmoltz energy -- Fluctuation Solution Theory; Thermodynamics -- Periodicals; Thermochemistry -- Periodicals; Thermodynamique -- Périodiques; Thermochimie -- Périodiques; Thermochemistry; Thermodynamics; Periodicals; 541.369
• DOI: 10.1016/j.jct.2015.07.013
• Languages: English
• ISSNs: 0021-9614

Abstract

Graphical abstract: Highlights: Densities for sub-saturated H2 O in CO2 with an average uncertainty of 0.07 kg · m −3 . A new custom high-pressure vibrating tube densimeter for acid gas fluid measurements. Molar volumes at infinite dilution for H2 O in high-pressure CO2 up to 35 MPa. Krichevskii parameter for H2 O in CO2, AKr = −17.7 ± 3.0 MPa. Reduced Helmholtz energy mixing parameters for (H2 O + CO2 ). Abstract: Post-compression CO2 delivered to sub-surface reservoirs often contains various impurities including sub-saturated water, where understanding phase behavior or chemical reactions involving water requires volumetric information. A new optically coupled vibrating tube densimeter has been developed for volumetric measurements of CO2 injectate fluids for compression conditions and injectate transportation (temperatures less than 423 K and pressures less than 35 MPa). Details regarding the design, operation and calibration of the instrument are reported. Density differences for sub-saturated H2 O in CO2 from T = (318 to 369) K and up to p = 35 MPa ( m = (0.053 to 0.065) mol · kg −1 ) are reported and used to calculate molar volumes. To our knowledge, these are the first sub-saturated measurements to be reported at the conditions typical for CO2 compression and transportation. As expected, the apparent molar volumes become significantly negative near the CO2 supercritical conditions. Using these molar volumes, we have (i) provided a fitted equation based on Fluctuation Solution Theory which can be used to calculate H2 O fugacity coefficients at infinite dilution, (ii) found the Krichevskii parameter to be AKr = −(17.7 ± 3.0) MPa and (iii) used the volumetric data to optimize reduced Helmholtz energy mixing parameters which can be used with high-accuracy equations-of-state ( γ v, 12 = 1.03070 and γ T, 12 = 0.81776). Comparisons to previously reported data for the H2 O-rich phase and the recent mixing model of Gernert and Span show the resulting corresponding state mixing parameters can be utilized for a much larger range of H2 O concentrations, temperatures up to T = 673 K and pressures up to p = 100 MPa.