V F-PROPATH:
Binary Mixtures by General
Equations

Binary mixtures in part V stand for those that have been formulated by applying mixing rule to base equation.
Base equations prepared are those of Peng-Robinson, CSD and BWR, at this moment.

522

F-PROPATH: Binary Mixture by General Equations

1. General Features
1.1 SUBPROGRAM REFERENCE
Every F–PROPATH user has to make the initiation process by writing the following 3 lines before the ﬁrst
REFERENCE to a F–PROPATH SUBPROGRAM(FUNCTION SUBPROGRAM or SUBROUTINE SUBPROGRAM) in the MAIN PROGRAM. If a user happens to want to use other settings in other places of his or her
PROGRAM UNIT, he or she is supposed to do a similar at those places.

CALL KPAMES(value of KPA, value of MESS)CALL STNKAS(value of KSTAN, value of KAS)CALL START1(J, value of KOMBI)

The arguments of the these SUBROUTINE SUBPROGRAMs specify the system of units, reference valuesof enthalpy and entropy, necessity of listing error messages to erroneous SUBPROGRAM REFERENCEs on
the standard output device. All arguments in these SUBROUTINE SUBGROGRAMs are INTEGERs. KPA
speciﬁes the units of pressure and temperature, and KAS unit of the amount of substance. KSTAN selects thereference values of enthalpy and entropy. The relation between KPA and the units of pressure and temperatureand that between KAS and the unit of amount of substance are shown in 1.3. F–PROPATH does not return any
messages when MESS= 0, while it does when MESS= 0. KSTAN diﬀers from one equation to another, and is
described in the chapter of each equation.
The argument KOMBI in SUBROUTINE START1 selects the kind of mixture from the predetermined list of
mixtures, which diﬀers from one general equation to another. Users are asked to consult with sections for eachequation. If KOMBI bears a value not listed on the list, level 2 error will occur. See the next section.

Operations to Manage Erroneous SUBPROGRAM REFERENCE

523

1.2 Operations to Manage Erroneous SUBPROGRAM
REFERENCE
A predetermined sequence of operations will occur to process an erroneous SUBPROGRAM REFERENCE
when an improper SUBPROGRAM REFERENCE has been done. Erroneous SUBPROGRAM REFERENCEs
are grouped into 2 levels, with the ascending severity of user’s mistake. A user has committed a more serious
mistake when a level 2 ERROR occurs than when a level 1 ERROR does.

1.2.1 Level 1 ERROR (Convergence Failure)
The method of iterations built in to some of the M-PROPATH SUBPROGRAMs to solve implicit relations
will not work somehow from time to time. F–PROPATH stops further iterations after executing the preset
number of iterations. Though the user is not responsible for level 1 ERROR, the F–PROPATH detects this typeof ERROR time to time, unfortunately.
A level 1 ERROR is processed as below.
FUNCTION SUBPROGRAM
value of REAL FUNCTION returned to the CALLing program : −1.0E + 10
value of INTEGER FUNCTION returned to the CALLing Program : −1
output to the standard output device:**** NO CONVERGENCE AT (NAME OF FUNCTION CALLED) ****SUBROUTINE SUBPROGRAM
value of error detection cord: −1
output to the standard output device:**** NO CONVERGENCE AT (NAME OF SUBROUTINE CALLED) ****

1.2.2 Level 2 ERROR (Invalid ARGUMENT(s))
A level 2 ERROR will occur when the ARGUMENT(s) a user transferred to M-PROPATH SUBPROGRAM
from his or her MAIN PROGRAM fail to drop in the proper range.
A level 2 ERROR is processed as below.
FUNCTION SUBPROGRAM
value of REAL FUNCTION returned to the CALLing Program: −1.0E + 20
value of INTEGER FUNCTION returned to the CALLing Program : −2
output to the standard output device:**** OUT OF RANGE AT (NAME OF FUNCTION CALLED) ****SUBROUTINE SUBPROGRAM
value of error detection cord: −2
output to the standard output device:**** OUT OF RANGE AT (NAME OF SUBROUTINE CALLED) ****

524

F-PROPATH: Binary Mixture by General Equations

1.3 System of Units and Reference Values of Enthalpy and
Entropy
All REAL quantities are in the fundamental SI or in the coherent derived SI with three exceptions. Pressure
can be in the unit of Pascal Pa or bar, temperature in the unit of Kelvin K or degree Celsius ◦ C. These depend on
the value of INTEGER KPA when a user referred the SUBROUTINE SUBPROGAM KPAMES(KPA, MESS)
shown in 1.1. The amount of substance can be in the unit of kilomole kmol or kilogram kg. INTEGER KAS
in the SUBROUTINE SUBPROGAM STNKAS(KSTAN, KAS) in 1.1 switches this. These go as shown in thetable below. The INTEGER KSTAN in the SUBROUTINE SUBPROGAM STNKAS(KSTAN, KAS) controls
the reference values of enthalpy and entropy and is explained for each speciﬁc equation, since they diﬀer fromone equation to another.
Table V-1.3-1 Units of Pressure and Temperature Speciﬁed by KPA
KPA
0
1
2
3
othersunit of pressure
Pa
bar
bar
Pa
Pa

unit of temperature
K
◦
C
K
◦
C
K

Table V-1.3-2 Amount of Substance Speciﬁed by KAS
KAS
01
othersamount of substance
kmol
kg
kmol

Reserved NAMEs

525

1.4 Reserved NAMEs
F–PROPATH uses a lot of NAMEs, listed below, for its own purpose. These are the NAMEs of SUBPROGRAMs and NAMED COMMON BLOCK to which a user can access directly and NAMEs of SUBPROGRAM
headed by ”FMF” which a user cannot access. A user is supposed to use the NAMEs of SUBPROGRAM and
COMMON BLOCK only when he/she does so in the original meaning. The letters in the ﬁrst column are theﬁrst LETTERs in the NAMEs listed in the same line.
Name of COMMON BLOCK, FUNCTION and SUBROUTINEA AKG, AKMOLC CRPMF FCM, FMF**** , COMMON /FMFC/
I IDENTM, IPHASEK KPAMESM MKTABL
N COMMON /NAME/P PBT, PDT, PSTMQ QMIXS START1, START2, STNKAS, SUBCRT, SUBM, SUBMIX, SUBPAR, SUBPB, SUBPD,SUBPST, SUBPUR, SUBTB, SUBTD, SUBTSP, SUBXY
T T68, T90, TBP, TDP, TSPM
U COMMON /UNIT/

526

F-PROPATH: Binary Mixture by General Equations

1.5 Terminology, Symbols and Compositions
The component with lower critical temperature is to be called as the ﬁrst component. A composition is
supposed to stand for the mole fraction or the mass fraction of the ﬁrst component. The symbolic distinctionof the compositions between the two phases and that between two saturation temperatures are done as shown
below.
total composition Z
composition at liquid phase X
composition at vapor phase Y
temperature at dew pointtemperature at bubble point
pressure at dew point
pressure at bubble point

:
:
:
:
:
:
:

composition of mixture as a whole
liquid composition at vapor-liquid equilibrium
vapor composition at vapor-liquid equilibrium
The lowest temperature of vapor for given pressure and Z
The highest temperature of liquid for given pressure and Z
The highest pressure of vapor for given temperature and Z
The lowest pressure of liquid for given temperature and Z

The NAMEs of FUNCTION and SUBROUTINE SUBPROGRAMs

527

1.6 The NAMEs of FUNCTION and SUBROUTINESUBPROGRAMs
NAMEs of FUNCTIONs and SUBROUTINEs are shown below and the full descripion of these SUBPROGRAMs is given in 1.7. Some of these SUBPROGRAMs have not been prepared in each equation shown in 2.
and after. These are listed there for each equation.

1.6.1 FUNCTIONREAL valued FUNCTION (conversion of temperature scale)
T68 = conversion from ITS–1990 to IPTS–1968
T90 = conversion from IPTS-1968 to ITS-1990
REAL valued FUNCTION (pure component)
CRPM = critical constants of pure component
FCM= fundamental constants of pure components
PSTM = vapor pressure of pure components
TSPM = saturation temperature of pure components
REAL valued FUNCTION (mixture)
AKG= mole fraction to mass fraction conversion
AKMOL = mass fraction to mole fraction conversion
PBT= bubble point pressure of mixture (temperature and X input)
PDT= dew point pressure of mixture (temperature and Y input)
QMIX= dryness fraction of mixture
TBP= bubble point temperature of mixture (pressure and X input)
TDP= dew point temperature of mixture (pressure and Y input)
INTEGER valued FUNCTIONIPHASE = distinction between phases of mixture
CHARACTER valued FUNCTIONIDENTM = name of pure components and version number

1.6.2 SUBROUTINE
initialization
KPAMES/STNKASSTART1/START2==

See 1.1
consult with chapters for each equation

pure component
MKTABL = listing critical constants and fundamental constants of pure component
SUBPST = saturation properies of pure components (temperature input)
SUBPUR = single phase properties of pure component
SUBTSP = saturation properties of pure components (pressure input)
mixtureSUBCRTSUBPAR
SUBPB
SUBPD
SUBTB
SUBTD
SUBM
SUBMIXSUBXYSUBMXHSUBMXT

=
=
=
=
=
=
=
=
=
=
=

critical constants of mixture
partial properties of mixturebubble point pressure and other properties of mixture (temperature and X input)
dew point pressure and other properties of mixture (temperature and Y input)
bubble point temperature and other properties of mixture (pressure and X input)
dew point temperature and other properties of mixture (pressure and Y input)
adiabatic and isobaric mixing of two streams
properties of mixture
properties of mixture at VLE
isobaric mixing of two mixtures with diﬀerent composition, enthalpy input
isobaric mixing of two mixtures with diﬀerent composition, temperature input

528

F-PROPATH: Binary Mixture by General Equations

1.7 Descriptions of FUNCTIONs and SUBROUTINEs
Shown in alphabetical order of NAMEs.
AKG
REAL FUNCTION AKG(Z) : mole fraction to mass fraction conversion
REAL Z: mole fraction [kmol/kmol]
REAL AKG : mass fraction [kg/kg]
AKMOL
REAL FUNCTION AKMOL(Z) : mass fraction to mole fraction conversion
REAL Z: mass fraction [kg/kg]
REAL AKMOL : mole fraction [kmol/kmol]
CRPM
REAL FUNCTION CRPM(I,A) : critical constant
INTEGERI : component
1 : ﬁrst component
2 : second component
CHARACTER*1 A : kind of critical constant returned‘T’ : critical temperature [K], [◦C]
‘P’ : critical pressure [Pa], [bar]‘V’ : critical volume [m3 /kmol], [m3 /kg]
‘H’ : critical enthalpy [J/kmol], [J/kg]‘S’ : critical entropy [J/(kmol·K)], [J/(kg·K)]
FCM
REAL FUNCTION FCM(I,A) : fundamental constants of pure components
INTEGERI : component
1 : ﬁrst component
2 : secund component
CHARACTER*1 A : kind of fundamental constant returned‘M’ : molar mass [kg/kmol]‘R’ : gas constant [J/(kg·K)]‘T’ : critical temperature [K] , [◦ C]‘P’ : critical pressure [Pa] , [bar]‘V’ : critical volume [m3 /kmol] , [m3 /kg]
‘E’ : acentric factor [-]IDENTM
CHARACTER*40 FUNCTION IDENTM(I,A) : name of pure component and version number
INTEGERI : component
1 : ﬁrst component
2 : second component
CHARACTER*1 A : kind of characters returned‘C’ : molecular formula‘S’ : name of substance‘V’ : version number

Descriptions of FUNCTIONs and SUBROUTINEs

529

IPHASEINTEGER FUNCTION IPHASE(T,P,Z) : distinction between phases of mixture
REAL T : temperature [K] , [◦C]REAL P : pressure [Pa] , [bar]
REAL Z : composition [kmol/kmol] , [kg/kg]
value of IPHASE
1
2
−1
−2

: single phase: two phase: Convergence failure: invalid ARGUMENT(s)KPAMESSUBROUTINE KPAMES(KPA,MESS)
See 1.11
MKTABLSUBROUTINE MKTABL(J,M): listing fundamental constants and isobaric speciﬁc heat at the ideal gas state
input
INTEGER M : value of KOMBI index to mixtures
outputSee example 4. Units of fundamental constants are preﬁxed as shown below and depend on neither KPA or
KAS.
molar mass
: [kg/kmol]
critical temperature : [K]critical pressure: [Pa]
critical volume: [m3 /kmol]acentric factor: [-]If you use just MKTABL in your main program, you do not need to CALL SUBROUTINE KPAMES,STNKAS
and START1 before calling MKTABL.
PBTREAL FUNCTION PBT(T,X) : bubble point pressure
REAL T: temperatuer [K], [◦ C]
REAL X: composition [kmol/kmol], [kg/kg]
REAL PBT : bubble point pressure [Pa], [bar]

PDT
REAL FUNCTION PDT(T,Y) : dew point pressure
REAL T: temperatuer [K], [◦C]REAL Y: composition [kmol/kmol], [kg/kg]
REAL PDT : dew point pressure [Pa], [bar]

PSTM
REAL FUNCTION PSTM(I,T) : saturation pressure of pure component
INTEGER I

REAL
REAL

: component
1 : ﬁrst component
2 : second componentT: temperature [K] , [◦C]
PSTM : saturation pressure [Pa], [bar]530

F-PROPATH: Binary Mixture by General EquationsQMIXREAL FUNCTION QMIX(T,P,Z) : dryness fraction
REAL T: temperature [K], [◦ C]
REAL P: pressure [Pa], [bar]
REAL Z: total composition [kmol/kmol], [kg/kg]
REAL QMIX : dryness fraction [kmol/kmol], [kg/kg]

START1SUBROUTINE START1(J,value of KOMBI)
See chapters of each equation
START2
SUBROUTINE START2(J,· · · · ·)See chapters of each equation
STNKASSUBROUTINE STNKAS(KSTAN,KAS)
See 1.1
SUBCRT
SUBROUTINE SUBCRT(I,J,T,P,Z,V,H,S) : critical constants of mixture
INTEGER I : type of problem (input, I=1,2)
I= 1 :input
REAL
Z : total composition [kmol/kmol], [kg/kg]
outputINTEGER J : error detection code
−1 : convergence failure−2 : invalid ARGUMENT(s)REAL
T : critical temperature [K], [◦ C]
P : critical pressure [Pa], [bar]V : critical volume [m3 /kmol], [m3 /kg]
H : critical enthalpy [J/kmol], [J/kg]
S : critical entropy [J/(kmol·K)], [J/(kg·K)]
I= 2 :input
REAL
T : critical temperature [K], [◦ C]
outputINTEGER J : error detection code
−1 : convergence failure−2 : invalid ARGUMENT(s)REAL
Z : total composition [kmol/kmol], [kg/kg]
P : critical pressure [Pa], [bar]V : critical volume [m3 /kmol], [m3 /kg]
H : critical enthalpy [J/kmol], [J/kg]
S : critical entropy [J/(kmol·K)], [J/(kg·K)]

SUBMXHSUBROUTINE SUBMXH(J,T,P,ZA,ZB,Z,V,HA,HB,H,S,W) : isobaric mixing of two mixtures with
diﬀerent compositions, enthalpy input
input
REAL
REAL
REAL
REAL
REAL

P : pressure [Pa] , [bar]ZA : total composition of A [kmol/kmol] , [kg/kg]
ZB : total composition of B [kmol/kmol] , [kg/kg]
HA : enthalpy of A [J/kmol] , [J/kg]
HB : enthalpy of B [J/kmol] , [J/kg]

Descriptions of FUNCTIONs and SUBROUTINEs

531

REAL
W : Fraction of A in Mixing [kmol/kmol] , [kg/kg]
outputINTEGER J : error detection code
−1 : convergence failure−2 : invalid ARGUMENT(s)REAL
T : temperature after mixing [K] , [◦C]
REAL
Z : total composition after mixing [kmol/kmol] , [kg/kg]
REAL
V : volume after mixing [m3 /kmol] , [m3 /kg]
REAL
H : enthalpy after mixing [J/kmol] , [J/kg]
REAL
S : entropy after mixing [J/(kmol·K)] , [J/(kg·K)]

SUBMXT
SUBROUTINE SUBMXT(J,T,P,ZA,ZB,Z,V,TA,TB,H,S,W) : isobaric mixing of two mixtures with
diﬀerent compositions, temperature input
input
REAL
P : pressure [Pa] , [bar]REAL
ZA : total composition of A [kmol/kmol] , [kg/kg]
REAL
ZB : total composition of B [kmol/kmol] , [kg/kg]
REAL
TA : temperature of A [K] , [◦ C]
REAL
TB : temperature of B [K] , [◦C]REAL
W : Fraction of A in Mixing [kmol/kmol] , [kg/kg]
outputINTEGER J : error detection code
−1 : convergence failure−2 : invalid ARGUMENT(s)REAL
T : temperature after mixing [K] , [◦C]
REAL
Z : total composition after mixing [kmol/kmol] , [kg/kg]
REAL
V : volume after mixing [m3 /kmol] , [m3 /kg]
REAL
H : enthalpy after mixing [J/kmol] , [J/kg]
REAL
S : entropy after mixing [J/(kmol·K)] , [J/(kg·K)]

SUBMIXSUBROUTINE SUBMIX(I,J,T,P,Z,V,H,S) : properties of mixture
INTEGER I : type of problem (input)
1 : inputs (T,P,Z) → outputs (V,H,S)
2 : inputs (P,Z,H) → outputs (T,V,S)
3 : inputs (P,Z,S) → outputs (T,V,H)
4 : inputs (P,Z,V) → outputs (T,H,S)
INTEGER J : error detection code
−1 : convergence failure−2 : invalid ARGUMENT(s)REAL
T : temperature [K] , [◦ C]
REAL
P : pressure [Pa] , [bar]REAL
Z : total composition [kmol/kmol] , [kg/kg]
REAL
V : volume [m3 /kmol] , [m3 /kg]
REAL
H : enthalpy [J/kmol] , [J/kg]
REAL
S : entropy [J/(kmol·K)] , [J/(kg·K)]

SUBPARSUBROUTINE SUBPAR(A,J,T,P,XL,XV): partial properties
input
CHARACTER*1 A : kind of partial properties, one of ‘V’,‘H’and‘S’
REAL
T : temperature [K], [◦ C]
REAL
P : pressure [Pa], [bar]532

F-PROPATH: Binary Mixture by General Equations

outputINTEGER J : error detection code
−1 : convergence failure−2 : invalid ARGUMENT(s)REAL ARRAY XL(2), XV(2) : one of volume, enthalpy and entropy
A=‘V’
XL(1) partial volume of ﬁrst component in liquid [m3/kmol], [m3 /kg]
XL(2) partial volume of second component in liquid [m3 /kmol], [m3 /kg]
XV(1) partial volume of ﬁrst component in vapor [m3/kmol], [m3 /kg]
XV(2) partial volume of second component in vapor [m3 /kmol], [m3 /kg]
A=‘H’
XL(1) partial enthalpy of ﬁrst component in liquid [J/kmol], [J/kg]
XL(2) partial enthalpy of second component in liquid [J/kmol], [J/kg]
XV(1) partial enthalpy of ﬁrst component in vapor [J/kmol], [J/kg]
XV(2) partial enthalpy of second component in vapor [J/kmol], [J/kg]
A=‘S’
XL(1) partial entropy of ﬁrst component in liquid [J/(kmol·K)], [J/(kg·K)]
XL(2) partial entropy of second component in liquid [J/(kmol·K)], [J/(kg·K)]
XV(1) partial entropy of ﬁrst component in vapor [J/(kmol·K)], [J/(kg·K)]
XV(2) partial entropy of second component in vapor [J/(kmol·K)], [J/(kg·K)]
SUBPB
SUBROUTINE SUBPB(J,T,P,X,V,H,S): bubble point pressure and other properties of mixture (temperature and X input)
input
REAL
T : temperature [K] , [◦ C]
REAL
X : composition [kmol/kmol] , [kg/kg]
outputINTEGER J : error detection code
−1 : convergence failure−2 : invalid ARGUMENT(s)REAL
P : bubble point pressure [Pa] , [bar]REAL
V : bubble point volume [m3 /kmol] , [m3 /kg]
REAL
H : bubble point enthalpy [J/kmol] , [J/kg]
REAL
S : bubble point entropy [J/(kmol·K)] , [J/(kg·K)]
SUBPD
SUBROUTINE SUBPD(J,T,P,Y,V,H,S): dew point pressure and other properties of mixture (temperature and Y input)
input
REAL
T : temperature [K] , [◦ C]
REAL
Y : composition [kmol/kmol] , [kg/kg]
outputINTEGER J : error detection code
−1 : convergence failure−2 : invalid ARGUMENT(s)REAL
P : dew point pressure [Pa] , [bar]REAL
V : dew point volume [m3 /kmol] , [m3 /kg]
REAL
H : dew point enthalpy [J/kmol] , [J/kg]
REAL
S : dew point entropy [J/(kmol·K)] , [J/(kg·K)]
SUBPST
SUBROUTINE SUBPST(I,J,T,PS,VL,VV,HL,HV,SL,SV): saturation properties of pure component (temperature intput)

Descriptions of FUNCTIONs and SUBROUTINEs
input
INTEGER I

REAL
T
outputINTEGER J

REAL
REAL
REAL
REAL
REAL
REAL
REAL

: component
1 : ﬁrst component
2 : second component: temperature [K] , [◦C]

: error detection code
−1 : convergence failure−2 : invalid ARGUMENT(s)PS : saturation pressure [Pa] , [bar]VL : liquid volume [m3 /kmol] , [m3 /kg]
VV : vapor volume [m3 /kmol] , [m3 /kg]
HL : liquid enthalpy [J/kmol] , [J/kg]
HV : vapor enthalpy [J/kmol] , [J/kg]
SL : liquid entropy [J/(kmol·K)] , [J/(kg·K)]
SV : vapor entropy [J/(kmol·K)] , [J/(kg·K)]

SUBPURSUBROUTINE SUBPUR(I,J,T,P,V,H,S) : single phase properties of pure components
input
INTEGER I : component
1 : ﬁrst component
2 : second component
REAL
T : temperature [K] , [◦ C]
REAL
P : pressure [Pa] , [bar]outputoutput are those of satureted liquid, when temperature-pressure is on saturation line
INTEGER J : error detection code
−1 : convergence failure−2 : invalid ARGUMENT(s)REAL
V : volume [m3 /kmol] , [m3 /kg]
REAL
H : enthalpy [J/kmol] , [J/kg]
REAL
S : entropy [J/(kmol·K)] , [J/(kg·K)]

SUBTB
SUBROUTINE SUBTB(J,T,P,X,V,H,S): bubble point temperature and other properties of mixture (pressure and X input)
input
REAL
P : pressure [Pa] , [bar]REAL
X : composition [kmol/kmol] , [kg/kg]
outputINTEGER J : error detection code
−1 : convergence failure−2 : invalid ARGUMENT(s)REAL
T : bubble point temperature [K] , [◦ C]
REAL
V : bubble point volume [m3 /kmol] , [m3 /kg]
REAL
H : bubble point enthalpy [J/kmol] , [J/kg]
REAL
S : bubble point entropy [J/(kmol·K)] , [J/(kg·K)]

SUBTD
SUBROUTINE SUBTD(J,T,P,Y,V,H,S): dew point temperature and other properties of mixture (pressure and Y input)
input

533

534

F-PROPATH: Binary Mixture by General Equations

REAL
P : pressure [Pa] , [bar]REAL
Y : composition [kmol/kmol] , [kg/kg]
outputINTEGER J : error detection code
−1 : convergence failure−2 : invalid ARGUMENT(s)REAL
T : dew point temperature[K] , [◦ C]
REAL
V : dew point volume [m3 /kmol] , [m3 /kg]
REAL
H : dew point enthalpy[J/kmol] , [J/kg]
REAL
S : dew point entropy [J/(kmol·K)] , [J/(kg·K)]

SUBTSPSUBROUTINE SUBTSP(I,J,TS,P,VL,VV,HL,HV,SL,SV): saturation properties of pure component (pressure input)
input
INTEGER I

REAL
P
outputINTEGER J

REAL
REAL
REAL
REAL
REAL
REAL
REAL

: component
1 : ﬁrst component
2 : second component: pressure [Pa] , [bar]: error detection code
−1 : convergence failure−2 : invalid ARGUMENT(s)TS : temperature [K] , [◦C]
VL : liquid volume [m3 /kmol] , [m3 /kg]
VV : vapor volume [m3 /kmol] , [m3 /kg]
HL : liquid enthalpy [J/kmol] , [J/kg]
HV : vapor enthalpy [J/kmol] , [J/kg]
SL : liquid entropy [J/(kmol·K)] , [J/(kg·K)]
SV : vapor entropy [J/(kmol·K)] , [J/(kg·K)]

SUBXY
SUBROUTINE SUBXY(J,T,P,X,Y,VL,VV,HL,HV,SL,SV) : properties of mixture at VLE
input
REAL
T
REAL
P
outputINTEGER J

REAL
REAL
REAL
REAL
REAL
REAL
REAL
REAL

: temperature [K] , [◦C]
: pressure [Pa] , [bar]: error detection code
−1 : convergence failure−2 : invalid ARGUMENT(s)X : composition of liquid X [kmol/kmol] , [kg/kg]
Y : composition of vapor Y [kmol/kmol] , [kg/kg]
VL : liquid volume [m3 /kmol] , [m3 /kg]
VV : vapor volume [m3 /kmol] , [m3 /kg]
HL : liquid enthalpy [J/kmol] , [J/kg]
HV : vapor enthalpy [J/kmol] , [J/kg]
SL : liquid entropy [J/(kmol·K)] , [J/(kg·K)]
SV : vapor entropy [J/(kmol·K)] , [J/(kg·K)]

TBP
REAL FUNCTION TBP(P,X) : bubble point temperature
REAL P: pressure [Pa], [bar]
REAL X: composition [kmol/kmol], [kg/kg]
REAL TBP : bubble point temperatuer [K], [◦C]Descriptions of FUNCTIONs and SUBROUTINEs
TDP
REAL FUNCTION TDP(P,Y) : dew point temperature
REAL P: pressure [Pa], [bar]
REAL Y: composition [kmol/kmol], [kg/kg]
REAL TDP : dew point temperatuer [K], [◦ C]

TSPM
REAL FUNCTION TSPM(I,P) : saturation temperature of pure components
INTEGER I

REAL
REAL

: component
1 : ﬁrst component
2 : second componentP: pressure of pure component [Pa] , [bar]TSPM : saturation temperature [K], [◦C]

535