The CO2–H2O system: IV. Empirical, isothermal equations for representing vapor-liquid equilibria at 110–350 °C, P ≤ 150 MPa
-
James G. Blencoe
Abstract
Empirical formulae are presented for calculating vapor-liquid equilibria (VLE) in the CO2-H2O system at 10 temperatures between 110 and 350 °C. At each temperature, separate functions are used to represent the bubble- and dew-point boundary curves that: originate at the saturation vapor pressure of water (Psat;H₂O) at XCO₂ = 0; diverge with increasing pressure up to ~P(XmaxCO₂) where ∂P/∂XCO₂ = +∞ along the dew-point curve; then converge with increasing pressure above P(XmaxCO₂). At temperatures below 265 °C and pressures > P(XmaxCO₂), the compositions of coexisting liquid and vapor [XCO₂L(V) and XCO₂V(L)] do not converge completely with increasing pressure due to the absence of critical behavior. Thus, relatively simple functions suffice to accurately represent VLE at those temperatures. In contrast, at T > 265 °C, XCO₂L(V) and XCO₂L(V) converge rapidly as P approaches Pc (the critical pressure in the CO2-H2O system at a given temperature between 265 and 374 °C and P ≤ 215 MPa). For those temperatures, therefore, more complex VLE formulae are required to achieve close representation of phase relations. For dew-point equations, this includes adding an exponential “correction term” to ensure that ∂P/∂XCO₂ = 0 at the critical points indicated by corresponding bubble-point functions.
Stable liquid-vapor coexistence in mixed-volatile systems requires ƒLi = ƒVI (isofugacity conditions) for all “i” (volatile components) in the two fluid phases. Thus, the equations presented in this paper specify numerous P-T-X conditions where ƒLH₂O = ƒVH₂O and ƒLCO₂ = ƒVCO₂ in the CO2-H2O system. These results have important applications in the ongoing effort to develop a more rigorous thermodynamic model for CO2-H2O fluids at geologically relevant temperatures and pressures.
© 2015 by Walter de Gruyter Berlin/Boston
Articles in the same Issue
- The origin of the color of pearls in iridescence from nano-composite structures of the nacre
- “Invisible„ gold revealed: Direct imaging of gold nanoparticles in a Carlin-type deposit
- Behavior of cation vacancy in kenotetrahedral Cr-spinels from Albanian eastern belt ophiolites
- Displacement and strain fields around a [100] dislocation in olivine measured to sub-angstrom accuracy
- Kiglapait mineralogy IV: The augite series
- Metasomatic formation of kosmochlor-bearing diopside in peridotite xenoliths from North Island, New Zealand
- Determination of standard thermodynamic properties of sulfides in the Ag-Au-S system by means of a solid-state galvanic cell
- Hydroxyl ordering in igneous apatite
- Accommodation of the carbonate ion in apatite: An FTIR and X-ray structure study of crystals synthesized at 2–4 GPa
- Mg/Si ratios of aqueous fluids coexisting with forsterite and enstatite based on the phase relations in the Mg2SiO4-SiO2-H2O system
- The activity of silica, water, and the equilibration of intermediate and silicic magmas
- The CO2–H2O system: IV. Empirical, isothermal equations for representing vapor-liquid equilibria at 110–350 °C, P ≤ 150 MPa
- Repercussions of size heterogeneity on the measurement of specific surface areas of colloidal minerals: Combination of macroscopic and microscopic analyses
- The crystal-structure of synthetic NaNa2Mg5Si8O21(OH)3, a triclinic C1̄ amphibole with a triple-cell and excess hydrogen
- High-pressure phase transitions in Ca0.2Sr0.8Al2Si2O8feldspar
- Phase transition of Ca-perovskite and stability of Al-bearing Mg-perovskite in the lower mantle
- Mineralogy and petrology of a mullite-bearing pseudotachylyte: Constraints on the temperature of coseismic frictional fusion
- New developments in two-feldspar thermometry
- Ordered distribution of Au and Ag in the crystal structure of muthmannite, AuAgTe2, a rare telluride from Sacarîmb, western Romania
- Polytypism of cookeite in low-grade metapelites of the Cameros Basin, Spain: Lack of correlation of well-ordered polytypes with pressure
- Evolution of mineral compositions during eclogitization of subducting basaltic crust
- Mass balance during retrogression of eclogite-facies minerals in the Rongcheng eclogite, eastern Sulu ultrahigh-pressure terrane, China
- Synthesis of REE and Y phosphates by Pb-free flux methods and their utilization as standards for electron microprobe analysis and in design of monazite chemical U-Th-Pb dating protocol
- The chemistry and crystal structure of okanoganite-(Y) and comparison with vicanite-(Ce)
- An automated system for phase identification and quantitative composition determination using the electron microprobe: Theory and applications
- Piston-cylinder calibration at 400 to 500 MPa: A comparison of using water solubility in albite melt and NaCl melting
- Letter. Comparative planetary mineralogy: V/(Cr + Al) systematics in chromite as an indicator of relative oxygen fugacity
- Letter. Porous titanosilicate nanorods in the structure of yuksporite, (Sr,Ba)2K4(Ca,Na)14(⃞,Mn,Fe) {(Ti,Nb)4(O,OH)4[Si6O17]2[Si2O7]3}(H2O,OH)n, resolved using synchrotron radiation
Articles in the same Issue
- The origin of the color of pearls in iridescence from nano-composite structures of the nacre
- “Invisible„ gold revealed: Direct imaging of gold nanoparticles in a Carlin-type deposit
- Behavior of cation vacancy in kenotetrahedral Cr-spinels from Albanian eastern belt ophiolites
- Displacement and strain fields around a [100] dislocation in olivine measured to sub-angstrom accuracy
- Kiglapait mineralogy IV: The augite series
- Metasomatic formation of kosmochlor-bearing diopside in peridotite xenoliths from North Island, New Zealand
- Determination of standard thermodynamic properties of sulfides in the Ag-Au-S system by means of a solid-state galvanic cell
- Hydroxyl ordering in igneous apatite
- Accommodation of the carbonate ion in apatite: An FTIR and X-ray structure study of crystals synthesized at 2–4 GPa
- Mg/Si ratios of aqueous fluids coexisting with forsterite and enstatite based on the phase relations in the Mg2SiO4-SiO2-H2O system
- The activity of silica, water, and the equilibration of intermediate and silicic magmas
- The CO2–H2O system: IV. Empirical, isothermal equations for representing vapor-liquid equilibria at 110–350 °C, P ≤ 150 MPa
- Repercussions of size heterogeneity on the measurement of specific surface areas of colloidal minerals: Combination of macroscopic and microscopic analyses
- The crystal-structure of synthetic NaNa2Mg5Si8O21(OH)3, a triclinic C1̄ amphibole with a triple-cell and excess hydrogen
- High-pressure phase transitions in Ca0.2Sr0.8Al2Si2O8feldspar
- Phase transition of Ca-perovskite and stability of Al-bearing Mg-perovskite in the lower mantle
- Mineralogy and petrology of a mullite-bearing pseudotachylyte: Constraints on the temperature of coseismic frictional fusion
- New developments in two-feldspar thermometry
- Ordered distribution of Au and Ag in the crystal structure of muthmannite, AuAgTe2, a rare telluride from Sacarîmb, western Romania
- Polytypism of cookeite in low-grade metapelites of the Cameros Basin, Spain: Lack of correlation of well-ordered polytypes with pressure
- Evolution of mineral compositions during eclogitization of subducting basaltic crust
- Mass balance during retrogression of eclogite-facies minerals in the Rongcheng eclogite, eastern Sulu ultrahigh-pressure terrane, China
- Synthesis of REE and Y phosphates by Pb-free flux methods and their utilization as standards for electron microprobe analysis and in design of monazite chemical U-Th-Pb dating protocol
- The chemistry and crystal structure of okanoganite-(Y) and comparison with vicanite-(Ce)
- An automated system for phase identification and quantitative composition determination using the electron microprobe: Theory and applications
- Piston-cylinder calibration at 400 to 500 MPa: A comparison of using water solubility in albite melt and NaCl melting
- Letter. Comparative planetary mineralogy: V/(Cr + Al) systematics in chromite as an indicator of relative oxygen fugacity
- Letter. Porous titanosilicate nanorods in the structure of yuksporite, (Sr,Ba)2K4(Ca,Na)14(⃞,Mn,Fe) {(Ti,Nb)4(O,OH)4[Si6O17]2[Si2O7]3}(H2O,OH)n, resolved using synchrotron radiation
