Mm. Dipippo et al., Ternary phase equilibria for the sodium chloride-sodium sulfate-water system at 200 and 250 bar up to 400 degrees C, FLU PH EQUI, 157(2), 1999, pp. 229-255
Phase equilibria in the NaCl-Na2SO4-H2O system were investigated at 200 and
250 bar for total salt concentrations ranging from 5 to 20 wt.% total salt
over temperatures ranging from 320 to 400 degrees C. In addition to provid
ing data for this ternary system, the experiments also added information on
the phase behavior of the two binary systems: NaCl-H2O and Na2SO4-H2O. For
salt mixture compositions which were rich in sodium sulfate, a solid phase
was observed to nucleate from the homogeneous liquid phase. Salt mixture c
ompositions which had a high fraction of sodium chloride exhibited a vapor
separation from a homogeneous liquid phase. By fitting curves to the solid-
liquid and vapor-liquid separation temperatures, the temperature and compos
ition of a constrained invariant point where liquid, solid salt and vapor a
re in equilibrium were estimated. These estimates were performed at discret
e compositions of 5, 10, 15 and 20 wt.% total salt at pressures of 200 and
250 bar. The temperature and composition of the invariant point increased w
ith increasing pressure following a simple thermodynamic model for boiling
point elevation in a nearly ideal solution. (C) 1999 Elsevier Science B.V.
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