Aspen Physical Property System - Physical Property Models

wij = Mass fraction of the jth constituent in
component i
hi s
4 Nonconventional Solid Property Models 297
= Specific enthalpy of solid component i
�fhj s = Specific enthalpy of formation of constituent j
Cp s
Parameter
Name/Element
= Heat capacity of the jth constituent in
component i
Symbol MDS Default Lower
Limit
Upper
Limit
Units
DHFGEN/J � fh j s x 0 — — MASS-ENTHALPY
HCGEN/1, 5, 9, …, 77 a i,j1 x — — — MASS-ENTHALPY
and
TEMPERATURE
HCGEN/2, 6, 10, …, 78 a i,j2 x 0 — — MASS-ENTHALPY
and
TEMPERATURE
HCGEN/3, 7, 11, …, 79 a i,j3 x 0 — — MASS-ENTHALPY
and
TEMPERATURE
HCGEN/4, 8, 12, …, 80 a i,j4 x 0 — — MASS-ENTHALPY
and
TEMPERATURE
The elements of GENANAL are used to input the mass percentages of the
constituents. The structure for HCGEN is: Elements 1 to 4 are the four
coefficients for the first constituent, elements 5 to 8 are the coefficients for
the second constitutent, and so on, for up to 20 constituents.
Enthalpy and Density Models
for Coal and Char
Coal is modeled in the Aspen Physical Property System as a nonconventional
solid. Coal models are empirical correlations, which require solid material
characterization information. Component attributes are derived from
constituent analyses. Definitions of coal component attributes are given in the
Aspen Plus User Guide, Chapter 6.
Enthalpy and density are the only properties calculated for nonconventional
solids. This section describes the special models available in the Aspen
Physical Property System for the enthalpy and density of coal and char. The
component attributes required by each model are included. The coal models
are:
� General coal enthalpy
� IGT Coal Density
� IGT Char Density