Concentrated Aqueous Sodium Chloride Solutions from 200 to 600°C and to 3000 bar. — Phase Equilibria and PVT‐Data

Abstract

The specific volume of aqueous sodium chloride solutions with 6, 10, and 20 weight percent salt was measured from 200°C to 600°C and from 100 bar to 3000 bar. The uncertainty of the data is below 0.5%. Data are given of temperature, pressure, volume and composition at 24 points on the two-phase boundary surface. About 230 values for the one-phase region are presented. The critical curve for the binary system runs from 374°C and 220 bar for pure water to 500°C and nearly 600 bar for a solution with 12% salt. The specific volume at this point is 2.0 cm3 g-'. At 600"C, 3000 bar and 20% salt a volume of 1.163 cm3 g-' was found. The apparatus and procedure, which uses an autoclave with variable volume and sapphire window is described.

The behaviour of components in complex fluid mixtures under high T-P conditions

“…Figure 7.5 shows how the volume of the system varies according to the NaCl content for a constant specified amount of water of 1 g. The lines representing variation in the system volume at the T and P considered in the present study are the result of averaging both the data available in the literature to 600°C (Gehrig et al, 1983;Hilbert, 1984) and experimental values retrieved at 700°C and 1 kbar by a gold bag procedure . The latter data are tabulated in Table 7.2.…”

Fluid Immiscibility in Metamorphic Rocks

“…A large body of experimental work on phase relations of the H 2 O-CO 2 -NaCl ternary at varying P and T conditions is available (Takenouchi and Kennedy 1965;Naumov et al 1974;Gehrig 1980;Gehrig et al 1986;Gibert et al 1998;Kotel'nikov and Kotel'nikova 1990;Johnson 1991;Frantz et al 1992;Shmulovich and Plyasunova 1993;Schmidt et al 1995;Shmulovich and Graham 1999;Schmidt and Bodnar 2000;Shmulovich and Graham 2004). Based on the data of Gehrig (1980), Bowers and Helgeson (1983a,b) developed a modified Redlich-Kwong (MRK) equation of state (EOS) for that ternary.…”

Thermodynamics of aqueous sodium chloride to 823 K and 1 kilobar (100 MPa)

“…Gl°(P2) -Gl°(Pi) = JVoldP, P1 [13] which is also given from the equation of state. For the solution, V1 and V2 were obtained from the volumetric data of Urusova (3) by finite difference between values for adjacent mole fractions.…”

“…Reasonably good fits were obtained at somewhat lower pressures varying from 215 bar at 623 K to 685 bar at 823 K. The resulting values of w are summarized in Table 1 At 623 and 673 K, values of w were estimated for higher pressures (above 225 and 600 bar, respectively). Some guidance was obtained from the volumetric data of Hilbert (11) and Gehrig (12,13), but their measurements do not extend near saturation composition. Thus, the choice of these w values was guided primarily by the well-determined values at lower and higher temperatures.…”

“…Thus, the vapor pressures and density measurements above 573 K have a precision on the order of 1% or a few percent, whereas the lower temperature data are more precise and are supplemented by heats of dilution and heat capacities. The most extensive and selfconsistent array of measurements are those of Urusova (3)(4)(5), and our treatment is based primarily on her data but with use of other measurements (6)(7)(8)(9)(10)(11)(12)(13) where available and accurate. Urusova (14) made some calculations of the activity coefficients of water on the basis of her measurements, but these are given only for a single pressure at a given temperature.…”