Aspen Physical Property System - Physical Property Models

Parameter
Name/
Element
2 Thermodynamic Property Models 117
Symbol Default MDS Lower
Limit
Upper Limit Units
XYZE/1 r x,I — — — — —
XYZE/2 r y-,I — — — — —
XYZE/3 r y+,I — — — — —
XYZE/4 r z,I — — — — —
XYZE/5 r e,I — — — — —
Electrolytes must be modeled as ion pairs in this system, while the individual
ions are components in the Aspen Physical Property System, so for these ion
pairs, the five parameters are stored in binary parameter BXYZE which has
elements corresponding to those of XYZE.
Parameter
Name/
Element
Symbol Default MDS Lower
Limit
Upper Limit Units
BXYZE/1 r x,CA — — — — —
BXYZE/2 r y-,CA — — — — —
BXYZE/3 r y+,CA — — — — —
BXYZE/4 r z,CA — — — — —
BXYZE/5 r e,CA — — — — —
The conceptual segment numbers of a cationic component and
an anionic component come from the dissociation of their
corresponding electrolyte component CA, as defined by the chemical equation
describing the dissociation of the electrolyte:
with
Since an electrolyte component CA can be measured by up to five conceptual
segments , we can calculate ri,C and ri,A as follows for systems of
single electrolyte.
For an electrolyte system where multi-electrolytes may be generated, a
simple mixing rule is used: