http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Studies of methods used in phase equilibrium calculations
Two general topics are covered in this dissertation: (1) new
procedures for phase equilibrium calculations and (2)
specific application of the new procedures to the C02/H20
system A robust and fast algorithm has been developed to
calculate phase equilibria based upon a new Gibbs energy
minimization method, the Equal Area Rule (EAR) method, for
multicomponent and/or multi-phase mixture systems. Eubank
and Hall (1995) have shown the equal area rule (EAR) applies
to the composition derivative of the Gibbs energy of a binary
system at fixed pressure and temperature regardless of
derivative continuity. In this dissertation, we show that EAR
can be extended up to quaternary systems (any by analogy to
any number of components). In ternary systems, a single
directional vector is sought in composition space; at
equilibria this vector is the familiar tie-line. A sensitive
criteria for equilibrium under EAR is equality of orthogonal
derivatives such as 9 r =- (aglaxi),2,P,Tat the end points
(cc and 0), where g =- (AmG/RT). Repeated use of the binary
algorithm published in the above reference allows rapid,
simple solutions for ternary problems. Using a similar
scheme, the EAR method was extended to quaternary system
Examples of applications covering up to three-phase mixture
cases are given. Another new criterion, termed the maximum
partial equal area rule (WEAR), searches for the directional
vector as presented in this dissertation. We define an area
(AOC) related to the overall composition as the partial area
inside the upper area (U) or lower area (L) on the g, - xi
diagrani. This area is always a maximum when equilibrium is
achieved in agreement with a thermodynamic proof presented
here within. In addition, a study is presented about the
prediction of the phase equilibrium behavior of the carbon
dioxide/water system. The model used in this work is the
Peng Robinson equation of state with the Wong-Sandler mixture
combining rules (MCR). The parameters used in the Wong-
Sandler MCR have been selected to minimize the deviations
between experimental data and prediction results for liquid-
phase solubilities. The model has been applied to pressures
up to 1000 bar, and temperatures up to 623 K Three-phase
pressures and compositions are also calculated using the EAR
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