Page 39 - Principles of Catalyst Development

20 Principles of Applied Reservoir Simulation

Table 3-1
Examples of Interfacial Tension
Fluid Pair IFT Range (niN/m or dyne/cm)

Air-Brine 72-100
Oil-Brine 15-40

Gas-Oil 35-65

Interfacial tension (IFT) can be estimated using the Macleod-Sugden
correlation. The Weinaug-Katz variation of the Macleod-Sugden correlation is
N e
y, (3.1)
'M L

where
o interfacial tension [dyne/cm]
1/4
3
parachor of component i [(dynes/cm) /(g/cm )]
1
chi
molecular weight of liquid phase
M L
My molecular weight of vapor phase
3
liquid phase density [g/cm ]
Pi
3
PK vapor phase density [g/cm ]
mole fraction of component / in liquid phase
x :
y t mole fraction of component i in vapor phase
Parachors are empirical parameters. The parachor of component i can be
estimated using the molecular weight M i of component i and the empirical
regression equation

P chi = 10.0 +2.92 M l (3.2)
This procedure works reasonably well for molecular weights ranging from 100
to 500. A more accurate procedure for a wider range of molecular weights is
given by Fanchi [1990].

Wettability
Wettability is the ability of a fluid phase to preferentially wet a solid
surface in the presence of a second immiscible phase. The wetting, or wettability,