NIST Standard Reference Database 4
NIST Thermophysical Properties of Hydrocarbon Mixtures Database (SUPERTRAPP)
Version 3.2
Users' Guide
Based on research sponsored by: The NIST Supercritical
Fluid Property Consortium and Standard Reference Data
M. L. Huber Physical and Chemical Properties Division
January 2007
National
The National Institute of Standards and Technology (NIST) uses its
best efforts to deliver a high quality copy of the Database and to
verify that the data contained therein have been selected on the basis of
sound scientific judgment. However, NIST makes no warranties to
that effect, and NIST shall not be liable for any damage that may result
from errors or omissions in the Database.
The mention of specific
products, trademarks, or brand names in this guide is for the purpose of
identification only. Such mention is not to be interpreted in any way as an
endorsement or certification of such products by NIST.
IBM-DOS, PC-DOS are registered trademarks of International
Business
© 1990, 1998,1999, 2003, 2007 Copyright by the U.S.
Secretary of Commerce on behalf of the United States of America. All rights
reserved. No part of this database may be reproduced, stored in a retrieval
system, or transmitted, in any form or by any means, electronic, mechanical,
photocopying, recording, or otherwise, without the prior written permission
of the distributor.
ACKNOWLEDGMENTS
This work was sponsored in part by a consortium
consisting of Air Products and Chemicals, Inc., BP America and Shell
Development Co. Additional support was provided by
CONTENTS
2.1 System requirements
2.2 Database files
2.3 Installation
4.1 BUBP, Bubble point pressure calculation
4.2 DEWP, Dew point pressure calculation
4.3 BUBT, Bubble point temperature calculation
4.4 DEWT, Dew point temperature calculation
4.5 FEED, Change the composition
4.6 FLTP, Isothermal flash (default)
4.7 FLTD, Isochoric flash (T,D flash)
4.8 FLTS, Isentropic flash (T,S Flash)
4.9 FLPH, Isenthalpic flash (P, H Flash)
4.10 FLPS, P,S flash
4.11 FLTH, T,H flash
4.12 KIJ, Change the extended corresponding states (EXCST) interaction
parameters
4.13 KIJV, Change the vapor-liquid equilibrium (VLE) interaction parameters
4.14 MASSIN, Toggle mass/mole input mode
4.15 MODEL, Change equation of state model
4.16 MODIFY, Change pure component property
data
4.17
4.18 SATF, Pure component saturation properties
4.19 SLATE, Change the components in
the mixture
4.20 TABLE, Generate a table
4.21 UNITS, Change the current units
4.22 CLOSE, Close the output file
4.23 EDIT, Edit the feed composition
4.24 OPEN, Open a new input or output file
4.25 RESET, Restart SUPERTRAPP
4.26 STOP, Terminate the program
4.27 DIR, Obtain the directory that is
associated with a pathname
4.28 PRINT, Print file on printer
4.29 SYSTEM, Execute a system command
4.30 TYPE, List a file on terminal
4.31 LIB, Create library file for use with SUPERTRAPP source code
5.1 Entry of a new component
I. List of Commands
II. List of Abbreviations
Appendix B SUPERTRAPP LIBRARY
LIST
Appendix C USE OF SOURCE CODE
SUBROUTINES
NIST SUPERTRAPP is a powerful,
interactive computer database for the prediction of thermodynamic and
transport properties of fluid mixtures. It may be used for pure fluids or
for mixtures of up to 20 components. The components are selected from a database
of 210 components, mostly hydrocarbons. It also can be used for petroleum
fractions that are characterized by an average boiling point and an API gravity.
NIST SUPERTRAPP performs phase equilibria calculations and gives the thermophysical
properties of all phases and the feed. These results include both equilibrium
properties (density, compressibility factor, enthalpy, entropy, Cp, Cp/Cv,
sound speed, Joule-Thomson coefficient) and transport properties (viscosity
and thermal conductivity). The database also has many help messages available,
and although it is has an old-fashioned interface that runs on DOS, it is
easy to use.
NIST SUPERTRAPP features allow users to:
─ perform bubble point
pressure and temperature calculations;
─ perform dew point pressure
and temperature calculations;
─ perform a variety of
flashes: (T,P), (T,D), (T,S), (P,H), (T,H),
and (P,S);
─ obtain properties of
pure components along the saturation
boundary;
─ compute tables of properties;
─ change units;
─ learn (and remember)
a new component not in the current database;
─ enter data from the
keyboard or from data files; and
─ save results in a file.
1.2 Uncertainties in Calculated Properties
Our objective for SUPERTRAPP
is to implement predictive models for nonpolar hydrocarbon systems that are
thermodynamically consistent and valid over a wide range of state conditions,
rather than to provide individual correlations for each property. The program does not contain experimental data;
it contains only models. The user should be aware that the uncertainties in
these models vary considerably depending on the fluid, property, and thermodynamic
state. It is thus impossible to give a simple, global statement of uncertainties.
Even for the most-studied fluids with equations of state based on accurate,
wide-ranging data, uncertainties are complicated functions of the temperature
and pressure. The interested user is referred to the original literature sources
discussing the development of the model. (References to the literature are
in Chapte
The user is further cautioned that, by the very nature
of a calculational database, property data are often displayed with more digits
than can be justified based on the accuracy of the property models or the
uncertainties in the experimental data to which the models were fitted.
2.1 System requirements
SUPERTRAPP runs in a DOS window under MS Windows 95,
98, 2000, NT, XP or ME. The package requires 430 kilobytes of available RAM
and a hard disk drive with 1.5 megabytes of available space.
A math coprocessor is required. A printer is required
to run the PRINT command.
2.2
Database files
The database
is supplied on CD-ROM, and contains the following files:
1
STPHELP
2
STPLIB2
3
STRAPP.EXE
4
LF90.EER
5
EXMPL1.TXT
6
EXMPL2.TXT
7
README.TXT
8
COPYRGHT.TXT
9
DEFAULTS
1
STPV2A.FOR
2
STPV2B.FOR
3
SAMPLE1.FOR, SAMPLE1.OUT
4
SAMPLE2.FOR, SAMPLE2.OUT
5
SAMPLE3.FOR, SAMPLE3.OUT
6
SAMPLE4.FOR, SAMPLE4.OUT
7
SAMPLEP.FOR, SAMPLEP.OUT
8
WRITLIB2.FOR
9
PORTLIB
10
LIBFILE
11
README2.TXT
12
Supertrapp.pdf
If any files are missing, please
contact the Standard Reference Data Program at (301) 975-2208.
2.3 Installation
Put the CD-ROM in the CD-ROM
drive (D, E, R— will vary depending on your particular computer). In Windows
3.1 or later or Windows NT, select File from the Program Manager’s Menu Bar
followed by Run from the File menu. In Windows 95, click the Start button
and select Run. In the Command line: box, type
D:\SETUP (where “D” is the
appropriate drive designation)
and press ENTER. Follow the remainder of the
Installation instructions. A NIST SUPERTRAPP 3.2 Program Group is created
at the end of installation.
NOTE: Because SUPERTRAPP allows
changing the database file (STPLIB2) permanently, keeping a backup copy of
the original release of STPLIB2 is strongly recommended.
NOTE: In some Windows applications
the MS-DOS window may remain open after the program is terminated. To close
the window, click the Close button in the upper right corner of the window
when the statement “Program Terminated – Exiting NIST4” appears.
After the installation process
has been completed successfully, you can proceed. There are a few general
comments about SUPERTRAPP to keep in mind. First of all, the program is case-insensitive
so that either upper or lower case input is allowed. Also, there are many
questions for which a YES or NO response is called for. The default answer
is whichever appears first after the question-for example, (N,Y) indicates
that NO is the default, while (Y,N) indicates that YES is the default. Pressing
ENTER is
equivalent to the default answer. Y or N is also acceptable. Typing a question
mark (?) will generally cause a context-appropriate help message to appear.
To start SUPERTRAPP, simply type from the DOS prompt
or launch from Windows: STRAPPAfter
a few seconds the sign-on banner appears. To start program execution, press
ENTER.
The database program proceeds
by displaying a set of questions, which are answered by keyboard entry. The
first is whether to use the defaults (for units, model, etc.). If the answer
is No, the program asks whether the compositions are to be inputted as mole
fractions. An ENTER,
N, or No response means the compositions are inputted as moles, and the program
computes the mole fractions. Should you choose to input in mole fraction mode,
the program will check that the sum of the mole fractions is unity. The next
question is whether to receive input from a previously prepared file. For
more information about file input, see the command OPEN described in Chapter
4.
The following questions concern
output to a file. You may want to save the results in a file and/or see the
results on the screen. To save results in a file, answer YES to this question.
See command OPEN in Chapter 4 for more details. The next questions deal with
units. SUPERTRAPP starts up with a default set of units (K, bar, liter, kJ,
mol, m, s, µpoise, mW). To change any or all of these units, answer YES to
this question. Details on changing units are covered in Chapter 4 under the
UNITS command.
The program asks for the number
of components in the mixture. Enter the appropriate number of species from
1 to 20. A zero causes the program to stop. After the number of components
is entered, the program asks for the names of the components. SUPERTRAPP has
a built-in library of 210 components, which are listed in Appendix B. To see
the library list on screen, enter ? in response to a prompt for a component
name. Be careful to type in the component name, or its synonym, exactly as
it appears on the screen or in Appendix B, or the program does not recognize
the name. (When this happens, you are given an opportunity to view the component
name list and correct the spelling. For a petroleum fraction, enter any of
the reserved names (petroleum #1, petroleum #2, petroleum #3 or their synonyms
pet1, pet2 and pet3). You are then asked to enter an average boiling point
and API gravity. The API gravity is given in degrees API, and is defined as
°API=(141.5/sp60) - 131.5, where sp60 is the specific gravity of the fluid
with respect to water at 60°F. If the component is still not in the database,
you then have the option of adding it. If the program does not recognize the
name of the component, it asks you a series of questions to allow you to enter
the component as a new fluid. For details on this procedure, see Chapter 5.1.
After the components have been input, you are asked to enter the composition
(unless there is only one component). (Note: although water is present in
the component list, calculations for pure water or for mixtures of more than
5 mole percent water are not permitted.)
Finally, you reach at the main
"command line," which is:
Enter command or, if you wish
to do a flash calculation, enter T(K) and P(bar) separated by a comma.
At this point, you can either
do a flash calculation by entering the temperature and pressure of interest,
or enter any of the commands that SUPERTRAPP supports, including the option
of changing any pure component property values stored in the library. For
details on this step, see the command MODIFY in Chapter 4 (4.16).
From the command line, any of the following commands
can be entered:
TECHNICAL
COMMANDS
BUBP Bubble
point pressure calculation BUBT Bubble point temperature calculation DEWT
Dew point temperature calculation FEED Change the composition FLTP Isothermal
flash (default command) FLTD T,D flash FLTS T,S (isentropic) flash FLPH
P,H (isenthalpic) flash FLPS P,S flash FLTH T,H flash KIJ Change extended
corresponding states (EXCST) interaction
CONTROL
COMMANDS
CLOSE Close the output file EDIT Edit the feed composition
OPEN Open a new input or output file RESET Restart SUPERTRAPP STOP Terminate
the program
SYSTEM COMMANDS
DIR List the directory that is associated with a pathname
PRINT Print file on printer SYSTEM Execute a DOS system command TYPE List
a file on terminal
OTHER COMMANDS
LIB Create portable library file
For additional help, type the name of the command
followed by a question mark, for example, UNITS?. Additional information on
the available commands
4.1 BUBP
A bubble point pressure calculation
computes the vapor (bubble) composition and pressure using known values of
the liquid composition (in equilibrium with the vapor) and the temperature.
To perform the calculation, enter "BUBP" mode at the command line,
and then enter the temperature at the point of interest. Enter a new command
or an "X" to leave the BUBP mode. A sample BUBP screen is given
below (Fig. 1). BUBP can be used for pure components or mixtures. Tables of
bubble points can be generated using the TABLE command, (see section 4.20).
2-Phase Bubble Point results at T = 200.000 K and P = 0.116754 MPa
-----Component------ ---Feed--- --Liquid--
--Vapor------Phi------K--
propane 0.500000 0.500000 0.927125E-01 0.870237E-01
.19E+00
ethane 0.500000 0.500000 0.907287 0.879587 .18E+01
Molar Basis
1.00000 1.00000 0.000000 Feed
Fraction
37.0823 37.0823 31.3695 Molar
Mass
0.451373E-02 0.451373E-02
0.965358 Comp. Factor, Z
0.576826 0.576826 0.228156E-02 D, kg/liter
-3159.78 -3159.78 -2917.66
H, kJ/kg
4.05164 4.05164 6.83080 S, kJ/kg.K
2.31336 2.31336 1.49442 Cp,
kJ/kg.K
1.62313 1.26284 Cp/Cv
1308.11 249.601 Sound Speed, m/s
-0.441795
36.0524 JT, K/MPa
204.504 6.23615 Visc., uPa.s
153.487 11.9750 Th. Cond.,mW/m.K
(VLE=PRS,PROPS=EXCST)
Figure 1. Sample bubble point pressure calculation.
This sample BUBP result shows
the type of information provided by the calculation. The mole fractions of
the components in the phases are given, along with the "Kvalue",
which is the ratio of the vapor phase composition of a component to the liquid
phase composition of that component. The relative quantities of the phases
present are also given in the line labeled “Feed Fraction.” For the example
shown, because it is a bubble point calculation, only a minute bubble of vapor
is present, and the vapor fraction is essentially zero.
The molecular weights of the
phases and feed are also given. Equilibrium properties (compressibility factor
(defined as Z=PV/RT), density (D), enthalpy (H), entropy (S), Cp, Cp/Cv, sound
speed and Joule-Thomson coefficient), as well as transport properties (viscosity,
thermal conductivity) are calculated. The final entry shows which model was
used in the calculations. The phase
4.2 DEWP
A dew point pressure calculation
finds the liquid (dew) composition and pressure using known values of the
vapor composition (in equilibrium with the liquid) and the temperature. To
perform the calculation, enter "DEWP" mode at the command line,
and then enter the temperature. To leave DEWP, enter any other valid command.
An "X" returns program control to the main command line. DEWP can
be used for pure components or mixtures. Tables of dew points can be generated
using the TABLE command. The output from a DEWP calculation is very similar
to that for a BUBP calculation. The mole fractions of the components in the
phases are given, along with the "Kvalue". The relative quantities
of the phases present are also given in the line labeled “Feed Fraction.”
For a dew point calculation, only a minute drop of liquid is present.
4.3 BUBT
A bubble point temperature
calculation computes the vapor (bubble) composition and temperature using
known values of the liquid composition and the pressure. To perform the calculation,
enter "BUBT" mode at the command line, and then enter the pressure
at the point of interest. Enter a new command or an "X" to leave
the BUBT mode. BUBT can be used for pure components or mixtures. Tables of
bubble points can be generated using the TABLE command. The type of information
provided by the BUBT calculation is the same as for BUBP. The difference is
that for BUBP, the temperature is a known input, while for BUBT the pressure
is a known input.
4.4 DEWT
A dew point temperature calculation
computes the dew (liquid) composition and temperature using known values of
the vapor composition and the pressure. To perform the calculation, enter
"DEWT" mode at the command line, and then enter the pressure at
the point of interest. Enter a new command or an "X" to leave the
DEWT mode. DEWT can be used for pure components or mixtures. Tables of dew
points can be generated using the TABLE command. The type of information provided
by the DEWT calculation is the same as for DEWP. The difference is that for
DEWP, the temperature is a known input, while for DEWT the pressure is a known
input.
4.5 FEED
The FEED command enables changing
the concentrations of the components in the mixture. If you enter FEED, the
program prompts for the new concentration of each component.
4.6 FLTP
An isothermal flash calculation
finds the quantities and compositions of the vapor and liquid phases in equilibrium
at a given pressure, temperature and overall composition. The isothermal flash
is the default command at the command line in SUPERTRAPP. Simply enter the
temperature and pressure (separated by a comma) at the point of interest.
If another command has been performed, to return to a flash calculation, type
the command "FLTP". A sample FLTP screen is shown below (Fig. 2).
The program is designed to operate within the range 10-1000 K and 0-3000 bar.
Points outside this range are ignored.
2-Phase Flash results at T = 265.000 K and P
= 1.00000 MPa -----Component------
---Feed--- --Liquid--
--Vapor------Phi------K--
propane 0.500000 0.554896 0.242160 0.190756 .44E+00
ethane 0.500000 0.445104 0.757840 0.677790 .17E+01
Molar Basis
1.00000 0.824466 0.175534 Feed
Fraction
37.0823 37.8523 33.4657 Molar
Mass
0.176969 0.345867E-01 0.845725 Comp. Factor, Z
0.951033E-01 0.496718
0.179596E-01 D, kg/liter
-2940.09 -2974.52 -2757.17
H, kJ/kg
4.96122 4.68395 6.43422 S, kJ/kg.K
2.59044 2.70354 1.98959 Cp,
kJ/kg.K
1.71037 1.33695 Cp/Cv
849.828 247.259 Sound Speed, m/s -0.119548
19.7208 JT, K/MPa
104.723 8.13051 Visc., uPa.s
114.109 19.3834 Th. Cond.,mW/m.K (VLE=PRS,PROPS=EXCST)
Figure 2. Sample results from an isothermal flash calculation.
The mole fractions of the components
in the phases present are given, along with the "Kvalue", which
is the ratio of the vapor phase molar composition of a component over the
liquid phase molar composition of that component. The relative quantities
of the phases present are also given in the line labeled “Feed Fraction”. For the example shown, if there is one mole
of feed, the flash calculation predicts 0.824466 moles of liquid and 0.175534
moles of vapor. In addition, the molecular weights of the phases and feed
are given. The sample result shows a case where two phases result from the
flash calculation. (It also is possible to obtain only one phase from a flash
calculation). SUPERTRAPP labels the phases present and gives properties of
the phases, calculated with the currently active model (EXCST or PRS), as
noted on the output. (To change the model, see the command MODEL). The phase
equilibrium is always done with the PRS model. Equilibrium properties as well
as transport properties are displayed in the output.
A T,D flash calculation determines the quantities and compositions of the
vapor and liquid phases in equilibrium at a given temperature, density and
overall composition. At the command line, enter FLTD to obtain a T,D flash.
Next, enter the temperature and density (separated by a comma) at the point
of interest. Output from FLTD looks very similar to FLTP.
4.8 FLTS
A T,S flash calculation determines
the quantities and compositions of the vapor and liquid phases in equilibrium
at a given temperature, entropy and overall composition. At the command line,
enter FLTS to obtain a T,S flash. Next, enter the temperature and entropy
(separated by a comma) at the point of interest. Output from FLTS looks very
similar to FLTP.
4.9 FLPH
A P,H flash calculation determines
the quantities and compositions of the vapor and liquid phases in equilibrium
at a given pressure, enthalpy and overall composition. At the command line,
enter FLPH to obtain a P,H flash. Next, enter the pressure and enthalpy (separated
by a comma) at the point of interest. Output from FLPH looks very similar
to FLTP.
4.10 FLPS
A P, S flash calculation determines
the quantities and compositions of the vapor and liquid phases in equilibrium
at a given pressure, entropy and overall composition. At the command line,
enter FLPS to obtain a P,S flash. Next, enter the pressure and entropy (separated
by a comma) at the point of interest. Output from FLPS looks very similar
to FLTP.
4.11 FLTH
A T,H flash calculation determines
the quantities and compositions of the vapor and liquid phases in equilibrium
at a given temperature, enthalpy and overall composition. At the command line,
enter FLTH to obtain a T,H flash. Next, enter the temperature and enthalpy
(separated by a comma) at the point of interest. Output from FLTH looks very
similar to FLTP.
4.12 KIJ
The KIJ command allows changing or viewing the interaction
parameters for the binary pairs in the mixture when using the EXCST model.
The parameters
can be used to fine-tune the
model to a particular point or set of data. In general, the model predictions
are sensitive to these parameters, so care should be taken when adjusting
them. When you enter KIJ, you are shown the current values of kij and lij
for each of the possible binary combinations of the mixture components and
prompted for new values. The kij parameter is used in computing the "f",
or energy-related shape factor, while the lij parameter is used in computing
the "h" or size-related shape factor for the mixture. If you do
not use this command, a default set of values is assumed. To view kij and
lij, but not change them, press ENTER after invoking KIJ. When you
change these parameters, the changes are NOT stored permanently in the database,
so it is necessary to re-enter the changes each time a new SLATE command is
invoked, or upon start-up.
4.13 KIJV
KIJV allows changing or viewing
the PRS interaction parameters without changing the EXCST parameters. The
phase equilibrium tends to be very sensitive to the KIJV interaction parameters,
so care should be used when adjusting them. Upon invoking the KIJV command,
you are shown the current value and prompted for a new value for the binary
interaction parameter for each possible binary pair in the mixture. The program
starts up with default values of Peng-Robinson binary interaction parameters,
which are found using a generalized procedure based on the general type or
family that a species belongs to. To view the kijv but not change them, press
ENTER after invoking KIJV. When
you change these parameters, the changes are NOT stored permanently in the
database, so it is necessary to re-enter the changes each time a new SLATE
command is invoked, or upon start-up.
4.14 MASSIN
This command toggles between input on a mass or mole
basis.
4.15 MODEL
SUPERTRAPP calculates phase
compositions with the Peng-Robinson equation of state (EOS) and offers a choice
of the Peng-Robinson (PRS) or the NIST extended corresponding states model
(EXCST) for the calculation of phase properties. The MODEL command allows
changing the model used for bulk phase property calculation. Enter PRS for
the Peng- Robinson EOS, or EXCST for the NIST extended corresponding states
model. The default mode is to compute phase properties using the EXCST model,
and vapor-liquid equilibria (VLE) with the Peng-Robinson model. The models
used are identified in the output display.
4.16 MODIFY
This command allows changing
pure component property data. It also can be used simply to view data for
a given component. (Note: you have the option to change data values ─
permanently or just temporarily. We STRONGLY recommend that, before changing
anything, you have a backup copy of the database file STPLIB2.) You are first
shown the current values of pure component property values. Next, you are asked which component to modify,
and which property to modify. The options for modification are:
|
Cp |
ideal gas heat capacity
|
Sh |
shape factors (see 4.16.8)
|
|
H0 |
enthalpy reference state |
Tb |
normal boiling point |
|
Hf |
heat of fusion |
Tc |
critical temperature |
|
LJ |
Lennard-Jones parameters
|
Tt |
triple point temperature
|
|
Mw |
molecular mass |
Vc |
critical volume |
|
Pc |
critical pressure |
w |
acentric factor |
|
S0 |
entropy reference state |
|
|
In
addition, if you want to change units at this step, type "Units"
or "Un." You can alter more than one component by entering the name
of each component. After fininshing the modifications, press enter to exit
the loop. You are asked if you want the modifications to be permanent. If
the answer is YES, the modifications are written to the random access file
that contains the database and essentially become permanent. If the answer
is NO, the modifications are lost when you change the component slate. This
allows performing calculations with your modifications until changing the
component slate and then being able to return to the original settings. More
detailed information on the MODIFY options is given in sections 4.16.1 - 4.16.9.
4.16.1 Cp
SUPERTRAPP uses ideal gas heat
capacities in the computation of enthalpy, entropy, thermal conductivity,
Cp, Cp/Cv, w, and JT. There are built-in values that may be changed and overwritten
by entering Cp data at this step. You will be asked to enter data (up to 20
points) as (T, ideal gas Cp) pairs. When entering values, bear in mind that
it is best to input the ideal gas heat capacities over as wide a temperature
range as possible.
4.16.2 S0, H0
You can change the reference value for entropy or
enthalpy. This is useful when trying to compare results with another program
or tabular data. The usual value for reference state enthalpy is the heat
of formation of the ideal gas at 298.15 K. For entropy, the
usual reference state value is the entropy of the ideal gas at 298.15 K and
one atmosphere. However, a zero or any other value
4.16.3 Tc, Pc, Vc
The critical properties of
the component can be changed with these commands.
4.16.4 Mw
The molecular mass can be changed
using this option.
4.16.5 Tb
The normal boiling point (the
temperature at which the species boils at a pressure of one atmosphere) can
be changed with this command.
4.16.6 Tt, Hf
These commands allow changing
the triple point temperature or the heat of fusion of a component. This information
is not essential to the operation of the program; it is used only in an ideal
solid solubility calculation to check for the presence of solids.
4.16.7 w
The Pitzer acentric factor
may be changed with this option. This factor is defined in terms of the reduced
vapor pressure of a pure species evaluated at a reduced temperature (Tr = T/Tc) of 0.7 and is given by
w = -1.0 - log10(Prsat)Tr=0.7
4.16.8 Sh
When SUPERTRAPP performs extended
corresponding states calculations (the EXCST model), it uses quantities called
shape factors. The current implementation uses vapor pressure and saturated
liquid density information to generate the shape factors for equilibrium thermodynamic
properties. It uses information on saturated liquid viscosities and thermal
conductivities to develop a kind of mass shape factor used in transport calculations.
To change these quantities, invoke the Sh option. You are asked if you have
vapor pressure data, then saturated liquid density data, then saturated liquid
viscosity and thermal conductivity data. You can enter data for any or all
of these quantities
4.16.9 Lennard-Jones Parameters
During the estimation of low
density transport properties, SUPERTRAPP can often improve the accuracy of
the predictions by using Lennard-Jones potential parameters. Some components
have built-in values for these parameters. Others have no values available
and a default method is used in the computations. You can change the values
of the Lennard-Jones collision diameter parameter (usually called "sigma")
and the Lennard-Jones energy well depth parameter ("epsilon/k")
by invoking the LJ option.
4.17
You have the option of always
entering a feed composition whose mole fractions sum to unity or having the
program normalize the input feed composition.
4.18 SATF
SATF allows the calculation
of saturation thermodynamic properties for the pure components in the mixture.
The saturated vapor and liquid densities, the saturation pressure, the heat
of vaporization and the fugacity coefficient (f/P) are displayed (but not
thermal conductivity or viscosity). (If this information is desired, run the
DEWP, BUBP, DEWT, BUBT or TABLE options using a pure fluid to get saturation
values). The model used for property calculation is also shown. To perform
the calculation, enter "SATF" at the command line. Terminate SATF
by pressing ENTER or entering "X".
4.19 SLATE
The SLATE command enables changing the components
in the mixture. You are asked for the number of components, and then the names
of the components. If you enter a question mark (?) at the "name the
component" prompt, the current component library can be listed. The component
names and synonyms supplied in SUPERTRAPP are given in Appendix B. For a petroleum
fraction, enter one of the reserved names for petroleum fractions (PETROLEUM
#1, PETROLEUM #2 or PETROLEUM #3) or synonyms (PET1, PET2 or PET3). You are
then asked to supply an average boiling point and API gravity. If the component
name is not in the database, you may enter it as a new component. For details
on the entry of a new component, see Chapter
4.20 TABLE
The TABLE generates tables for selected combinations of independent and output
variables. The choices of independent variables are: T, P, D, H, and S. Also
available is a "SAT" option that provides results along the vapor-liquid
saturation boundary and is valid for both pure fluids and mixtures. You are
asked to input the minimum, maximum and increment values for the independent
variables chosen for the table. Up to seven output variables can be selected.
For a pure fluid, the choices are: T, P, D, Z, H, S, viscosity, thermal conductivity,
sound speed, MW, Cp, Cv, and Joule-Thomson coefficient.
For mixtures, there are additional choices available: equilibrium phase compositions,
Kvalues (defined as yi/xi where yi is the mole fraction of i in
the vapor phase, and xi is the
mole fraction of i in the liquid phase), and the feed fraction in each resulting
phase. The feed fraction shows how the feed is "split" between the
phases.
4.21 UNITS
It is possible to select from
various input/output unit combinations in SUPERTRAPP. This command brings
up a menu-driven unit selection routine. The current units and the unit options
are shown on the menu, as shown below. To change a specific unit, enter the
new unit. For example, to change the pressure to megapascals enter "MPA".
To select one of four "default" sets of units, enter a number between
1 and 4. To exit, enter an "X". For example, to enter several units
on one line and exit, type,
This selects pressures in MPa, energies in calories and exits the Units subroutines. To see the menu again, press ENTER.
4.22 CLOSE