1. Eric Carlson’s Recommendations
Figure 1
Non-electrolyte
See Figure 2 E?
Polar
Electrolyte
Electrolyte NRTL
Or Pizer
Real
Peng-Robinson,
Redlich-Kwong-Soave,
Lee-Kesler-Plocker
All
Non-polar R?
Chao-Seader,
Grayson-Streed or
Braun K-10
Polarity
Pseudo & Real
Real or
pseudocomponents P? R? P?
Pressure
Vacuum
Braun K-10 or ideal E?
Electrolytes

2. Figure 2 LL? ij? P? LL? ij? Yes NRTL, UNIQUAC and their variances Yes
WILSON, NRTL,
UNIQUAC and
their variances
ij?
(See also
Figure 3)
P < 10 bar No
Yes No
UNIFAC LLE P?
LL?
Polar
Non-electrolytes
P > 10 bar No
UNIFAC and its
extensions
Schwartentruber-Renon
PR or SRK with WS
PR or SRK with MHV2
LL?
Yes
Liquid/Liquid
ij? P?
Pressure No
PSRK
PR or SRK with MHV2
ij?
Interaction Parameters
Available

3. Figure 3 DP? Wilson, NRTL, UNIQUAC, or UNIFAC with special EOS
for Hexamers
Figure 3
Hexamers
DP?
Yes
Wilson, NRTL, UNIQUAC,
UNIFAC with Hayden O’Connell
or Northnagel EOS
Dimers
VAP?
Wilson
NRTL
UNIQUAC
UNIFAC
Wilson, NRTL,
UNIQUAC, or UNIFAC*
with ideal Gas or RK EOS No
VAP?
Vapor Phase Association
UNIFAC* and its Extensions
DP?
Degrees of Polymerizatiom

4. Bob Seader’s Recommendations
Yes
Figure 4
PSRK
HC?
Hydrocarbons
PC?
Yes
LG?
Light gases No E?
Electrolyte
See Figure 5
Yes
LG?
Yes
PC?
Organic Polar
Compound
See Figure 6 No
PC?
HC? No
See Figure 5 No
Yes
Modified NRTL E? No
Special: e.g., Sour Water (NH3, CO2, H2S, H2O)
Aqueous amine solution with CO2 and H2S

5. Figure 5 P? T? BP? Critical PR Cryogenic Narrow or wide Non-Critical
PR, BWRS T?
HC and/ or LG
Non- Cryogenic
BP?
SRK, PR
Very wide
BP?
Boiling point range
of compound
LKP T?
Temperature region P?
Pressure region

6. Figure 6 PPS? BIP? Yes NRTL, UNIQUAC Available No PC with HC Wilson
Not Available
BIP?
Binary Interaction
Parameters
UNIFAC
PPS?
Possible Phase
Splitting