SELECTING THERMODYNAMIC
PROPERTY METHODS
A
key
requirement
of
process
design
is
the
need
to
accurately
reproduce
the
various
physical
properties
that
describes
chemical
species
.
The
property
packages
available
in
HYSYS
allow
you
to
predict
properties
of
mixtures
ranging
from
well
defined
light
hydrocarbon
systems
to
complex
oil
mixtures
and
highly
non

ideal
(
non

electrolyte)
chemical
systems
.
PHYSICAL PROPERTIES
The physical properties required for modeling and simulation
often includes,
Molecular reaction and kinetic data.
Thermodynamic properties
Transport properties
MOLECULAR REACTION & KINETIC DATA
In this case Critical properties are,
Rate equation
Activation energies
Reaction mechanism
THERMODYNAMIC PROPERTIES
Enthalpy
Entropy
Fugacity coefficient
Gibbs free energy
TRANSPORT PROPERTIES
Diffusion coefficient
Thermal conductivities
Viscosities
HYSYS
provides
enhanced
equations
of
state
(
PR
and
PRSV)
for
rigorous
treatment
of
hydrocarbon
systems
;
semi
empirical
and
vapour
pressure
models
for
the
heavier
hydrocarbon
systems
;
steam
correlations
for
accurate
steam
property
predictions
;
and
activity
coefficient
models
for
chemical
systems
.
All
of
these
equations
have
their
own
inherent
limitations
.
So
HYSYS
includes
following
methods
for
the
estimation
of
Physical
properties,
Equations
of
state
Activity
models
Chao

Seader
based
empirical
methods
Vapour
pressure
models
an
Miscellaneous
methods
.
EQUATIONS OF STATES
The
table
lists
some
typical
systems
and
recommended
correlations
.
PENG

ROBINSON EOS
For
oil,
gas
and
petrochemical
applications,
the
Peng

Robinson
EOS
(
PR
)
is
generally
the
recommended
property
package
.
It
rigorously
solves
any
single,
two

phase
or
three

phase
system
with
a
high
degree
of
efficiency
and
reliability,
and
is
applicable
over
a
wide
range
of
conditions
,
as
shown
in
the
following
table
.
the
Peng

Robinson
equation
of
state
supports
the
widest
range
of
operating
conditions
and
the
greatest
variety
of
systems
.
The
Peng

Robinson
and
Soave

Redlich

Kwong
equations
of
state
(EOS)
generate
all
required
equilibrium
and
thermodynamic
properties
directly
.
PR AND SRK
The
PR
equation
of
state
applies
a
functionality
to
some
specific
component

component
interaction
parameters
.
Key
components
receiving
special
treatment
include
He,
H
2
,
N
2
,
CO
2
,
H
2
S,
H
2
O,
CH
3
OH
The
PR
or
SRK
EOS
should
not
be
used
for
non
ideal
chemicals
such
as
alcohols
,
acids
or
other
components
.
They
are
more
accurately
handled
by
the
Activity
Models
(highly
non
ideal)
or
the
PRSV
EOS
(moderately
non

ideal)
.
LEE KESLER PLÖCKER EQUATION
The
Lee
Kesler
Plöcker
equation
is
an
accurate
general
method
for
non
polar
substances
and
mixtures
.
ACTIVITY MODELS
ACTIVITY MODELS
Although
equation
of
state
models
have
proven
to
be
very
reliable
in
predicting
properties
of
most
hydrocarbon
based
fluids
over
a
large
range
of
operating
conditions,
their
application
has
been
limited
to
primarily
non

polar
or
slightly
polar
components
.
Polar
or
non

ideal
chemical
systems
have
traditionally
been
handled
using
dual
model
approaches
.
EXTENDED AND GENERAL NRTL
With
a
wide
boiling
point
range
between
components
.
where
you
require
simultaneous
solution
of
VLE
and
LLE,
and
there
exists
a
wide
boiling
point
range
or
concentration
range
between
components
.
CHAO
SEADER
MODELS
VAPOUR PRESSURE MODELS
MISCELLANEOUS MODELS
VAPOUR PRESSURE MODEL
The
Vapour
Pressure
options
include
the
Modified
Antoine,
BraunK
10
,
and
EssoK
packages
MISCELLANEOUS

SPECIAL
APPLICATION METHODS
Amines Property Package
STEAM PACKAGE
HYSYS
includes
two
steam
packages
:
•
ASME
Steam
•
NBS
Steam
Both
of
these
property
packages
are
restricted
to
a
single
component,
namely
H
2
O
.
ASME
Steam
accesses
the
ASME
1967
steam
tables
.
The
limitations
of
this
steam
package
are
the
same
as
those
of
the
original
ASME
steam
tables
,
i
.
e
.
,
pressures
less
than
15000
psia
and
temperatures
greater
than
32
°
F
(
0
°
C)
and
less
than
1500
°
F
.
Selecting
NBS_Steam
utilizes
the
NBS
1984
Steam
Tables,
which
reportedly
has
better
calculations
near
the
Critical
Point
.
ASSIGNMENT
PUMP
Pumps
are
used
to
move
liquids
.
The
pump
increases
the
pressure
of
the
liquid
.
Water
120
C
and
3
bar
is
fed
into
a
pump
that
has
only
10
%
efficiency
.
The
flow
rate
of
the
water
is
100
kgmole
/h
and
its
outlet
pressure
from
the
pump
is
84
bar
.
Using
Peng

Robinson
equation
of
state
as
a
fluid
package,
determine
the
outlet
temperature
of
the
water
.
RESULTS
This
example
shows
that
pumping
liquid
can
increase
their
temperature
.
In
this
case,
the
pump
was
only
10
%
efficient
and
it
caused
18
°
C
in
the
temperature
of
the
water
.
The
less
efficient
a
pump
is,
the
greater
the
increase
in
the
temperature
of
the
fluid
being
pumped
.
This
arises
because
in
a
low
efficient
pump,
more
energy
is
needed
to
pump
the
liquid
to
get
the
same
outlet
pressure
of
a
more
efficient
pump
.
So
the
extra
energy
gets
transferred
to
the
fluid
.
COMPRESSOR
Compressors
are
used
to
move
gases
.
The
compressor
increases
the
pressure
of
the
gases
.
A
mixture
of
natural
gas
(C
1
,
C
2
,
C
3
,
i

C
4
,
n

C
4
,
i

C
5
,
n

C
5
,
n

C
6
,
C
7
)
at
100
C
and
1
bar
is
fed
into
a
compressor
that
has
only
30
%
efficiency
.
The
flow
rate
of
the
natural
gas
is
100
kgmole
/h
and
its
outlet
pressure
from
the
compressor
is
5
bar
.
Using
Peng

Robinson
equation
of
state
as
a
fluid
package,
determine
the
outlet
temperature
of
the
natural
gas
.
If
the
outlet
temperature
is
400
⁰
C
,
what
is
the
efficiency
of
the
compressor?
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