NIST Mixture Property Database
October 1992
(c) 1988 copyright by the U.S. Department of Commerce on behalf of the United States. 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
Much of the original development of the database program and an initial version of this Users' Guide can be credited to James F. Ely at the Fluid Mixtures Data Center. Marcia L. Huber at the Data Center also deserves credit for program development and testing, as well as for portions of this documentation. The NIST Supercritical Fluid Property Consortium and Standard Reference Data provided partial funding for research and development of the Database. Geraldine Dalton of SRD deserves much credit for preparation of the program for general distribution.
Chapter 1 INTRODUCTION
Chapter 2 SYSTEM REQUIREMENTS AND INSTALLATION
2.1 Requirements
Chapter 3 RUNNING NIST14
Chapter 4 COMMAND OPTIONS
4.1 BUBP, Bubble point pressure calculation
4.2 BUBT, Bubble point temperature calculation
4.3 CLOSE, Close the output file
4.4 DEWP, Dew point pressure calculation
4.5 DEWT, Dew point temperature calculation
4.6 DIR, Obtain the directory that is associated with a pathname
4.7 EDIT, Edit the feed composition
4.8 FEED, Change the composition
4.9 FLTP, Isothermal flash (default) calculation
4.10 KIJ, Change Extended Corresponding States (EXCST) interaction parameters
4.11 KIJV, Change the vapor-liquid equilibrium (VLE) interaction parameters
4.12 MASSIN, Toggle the mass/mole input/output mode
4.13 NORMAL, Toggle the composition mode
4.14 OPEN, Open a new input or output file
4.15 PRINT, Print file on printer
4.16 RESET, Restart NIST14
4.17 SATF, Pure component saturation properties
4.18 SLATE, Change the components in the mixture
4.19 STOP, Terminate the program
4.20 SYSTEM, Execute a system command
4.21 TABLE, Generate a table
4.22 TYPE, List a file on screen
4.23 UNITS, Change the current units
Chapter 5 FILE INPUT
Chapter 6 REFERENCES
Additional Information About the Database:
NOMENCLATURE
LIST OF PROPERTIES CALCULATED BY NIST14
The NIST Mixture Property Database is an interactive program written in standard FORTRAN 77. Its purpose is to provide accurate calculations of the density, phase equilibrium, enthalpy, entropy, heat capacity and sound velocity for mixtures composed of a variety of well studied fluids. In addition, the Joule-Thomson coefficient, viscosity and thermal conductivity are estimated.
The program uses a Peng-Robinson equation of state for coexisting-phase composition calculations. The NIST Extended Corresponding States model with exact shape factors and van der Waals one-fluid mixing rules are used for single phase properties. Since the model uses exact shape factors, the calculations are nearly exact for the allowable pure fluids, and the uncertainties in the mixture predictions only reflect uncertainties caused by the mixing rules and selection of binary interaction parameters.
The program contains many on-line help messages.
The NIST14 database features commands that allow you to:
The computer program can be downloaded from the online catalog or is supplied on floppy disks. The program consists of the following files:
If any are missing, please contact the Standard Reference Data Program at srdata@enh.nist.gov or 301 975 2208.
Chapter 2: SYSTEM REQUIREMENTS AND INSTALLATION
drive:\mydir\setup
where drive is the drive letter (C,
D, etc), mydir is the directory in which the setup program resides, and setup
is the name of the setup program. Press <Enter>. Follow the remainder
of the installation instructions. For Windows 3.1x, Windows 95, or Windows NT
a Program Group or Folder (default NIST Mixture Property Database) will be created
at the end of installation.
Now that you have created a NIST14 subdirectory and copied the program files to your machine, you can proceed. There are a few general comments about the Database that you should know before you start. First of all, the program is case-insensitive so that you may use either upper or lower case input. Also, there are many questions where a YES or NO response is called for. The default answer is NO, so typing a carriage return (or the end-of-file character CTRL-Z) is equivalent to a NO. The single letters Y or N are also acceptable.
If you do not understand a question, typing a question mark (?) followed by ENTER (or a carriage return) will generally cause a context-appropriate help message to appear. Entering STOP, BYE, or QUIT in response to a YES/NO question will terminate the program. The STOP command is also available as one of the COMMAND options, and CTRL-C will also end the program execution.
To start the NIST Mixture Property Database use the icon created by the setup program or at the DOS prompt type:
NIST14
After a few seconds the sign-on banner will appear. To start program execution, you must type a carriage return (usually the ENTER key). To read brief introductory material about the Database, enter a question mark (?) at this point.
The first question asks if the input is to be read from a computer file. This optional file input is discussed in Chapter 5. A NO answer (NO, no, N, n, No, nO, or carriage return) will allow interactive (keyboard) input into the program.
Next, the user is asked if the calculated results are to be output to a file.
You may want to save the results in a data file for further study and/or see the results on the screen. If you want to save the results in a file, answer YES to the question and you will be prompted to key in the output file name and asked if the output should also be written to the terminal. For more information on data file output, see the command OPEN described in Chapter 4.14.
The next question deals with units. The default set of units in NIST14 consists of K, bar, liter (equivalent to dm3), kJ, mol, m, s, P (micropoise), mW. You may change any or all of these units by answering YES to this question, which will place you in a units menu. Details on changing units are covered in Chapter 4.23 under the UNITS command.
You are next prompted to enter the number of components in the mixture. You may enter any number from 1 to 17. A zero will cause the program to stop. After entering the number of components, you will be asked to enter the names of the components. The NIST14 library comprises 17 well studied fluids which are listed in Appendix C. You may see the library list on the screen by entering a ? in response to a component name. You must be careful to type in the component name, or its synonym, exactly as it appears in Appendix C, or the program will not recognize the name. (When this happens, you will be given an opportunity to view the component name list and correct your spelling.) After the components have been successfully entered, you will be asked to enter the composition if a mixture was specified.
The user has the option of entering compositions (and getting output) on either a molar basis or a mass basis. The default option (NO response) corresponds to molar input. Next the user has an option of using either absolute input (number of moles or number of grams of each component) or fraction input (mole fraction or mass fraction of each component). The default NO response means the components can be entered in an absolute mode and the program will compute the mole fractions. If you choose to input in mole fraction or mass fraction modes, the program will check that the sum of your fractions is one.
Finally, you are at the main "command line" which looks like this:
If you have changed units, the chosen units for temperature (T) and pressure (P) will be given in this prompt. At this point, you may do an isothermal flash calculation by simply entering the temperature and pressure of interest, separated by a comma. Alternatively, you may enter any of the commands that NIST14 supports, as listed in Chapter 4 of this manual.
The output from any calculational option is straightforward to interpret; abbreviations are defined in Appendix B of this manual. The same output will be written to the screen (if selected) and to the chosen file (if selected). The number of phases output depends on the state point (and computation) selected. The feed column which is output may represent a hypothetical state with composition as specified by the user and pressure and temperature given in the first line of output. The feed density represents an overall density encompassing all phases present, and the extensive entropy, enthalpy, and heat capacity represent total values associated with all states present in their proper proportions.
Compositions are given as mole fractions, if molar input was used, or in mass fractions, if mass input was used. The phrase "Molar Basis" or "Mass Basis" is given in the feed column to remind the user which option was specified. If input (and output) is on a molar basis, the phase feed fractions are based on the amount (number of moles) of each phase which may be present. If input (and output) is on a mass basis, the phase feed fraction is based on the mass (number of grams) of each phase which may be present.
From the command line, you may enter any of the following commands:
For on-line help, simply type the name of the command followed by a question mark, for example, UNITS?. Additional information on the available commands is given in the following sections. A list of available commands can be displayed by entering a question mark at the main interactive prompt.
A bubble point pressure calculation computes the vapor (bubble) composition and pressure using known values of the liquid (or feed) composition 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 to exit the BUBP mode. A sample BUBP screen is given below.
The sample BUBP results show the type of information provided by the calculation. The compositions (in this case mole fractions) of each phase 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 "Kvalue" is always based on molar compositions.) The relative quantities of the phases present are also given in the line labeled feed fraction. For the example shown, since it is a bubble point calculation, only a minute bubble of vapor is present. The molar masses (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 (JT)), as well as transport properties (viscosity, thermal conductivity) are calculated.
If the input temperature is greater than the maxcondentherm (or very near the critical temperature), the message DEWP/BUBP COULD NOT LOCATE THE PHASE BOUNDARY is given, and calculations are made at an extrapolated pressure. If only one component is given, saturation values are found. For a pure component, the SATF option may also be used to find phase boundary information.
A bubble point temperature calculation computes the vapor (bubble) composition and temperature using known values of the liquid (or feed) 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 to exit the BUBT mode. The output of the BUBT command looks similar to output of the BUBP command of section 4.1. If the input pressure is greater than the maxcondenbar (or very near the critical pressure), the message DEWT/BUBT COULD NOT LOCATE THE PHASE BOUNDARY is given, and calculations are made at an extrapolated temperature. If only one component is given, saturation values are found. For a pure component, the SATF option may also be used to find phase boundary information.
The CLOSE command closes the current output file. Combinations of OPEN and CLOSE commands enable you to save your results in different files. (Only one output file may be open at a time.)
A dew point pressure calculation computes the liquid (dew) composition and pressure using known values of the vapor (or feed) composition and the temperature. To perform the calculation, enter DEWP mode at the command line, and then enter the temperature at the point of interest. Enter a new command to exit the DEWP mode. A sample DEWP screen is given below.
The sample DEWP results show the type of information provided by the calculation. The compositions (in this case mole fractions) of each phase 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 "Kvalue" is always based on molar compositions.) The relative quantities of the phases present are also given in the line labeled feed fraction. For the example shown, since it is a dew point calculation, only a minute drop of liquid is present. The molar masses (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 (JT)) as well as transport properties (viscosity, thermal conductivity) are calculated.
If the input temperature is greater than the maxcondentherm (or very near the critical temperature), the message DEWP/BUBP COULD NOT LOCATE THE PHASE BOUNDARY is given, and calculations are made at an extrapolated pressure. If only one component is given, saturation values are found. For a pure component, the SATF option may also be used to find phase boundary information.
A dew point temperature calculation computes the liquid (dew) composition and temperature using known values of the vapor (or feed) 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 to exit the DEWT mode. The output of the DEWT command looks similar to output of the DEWP command of section 4.4. If the input pressure is greater than the maxcondenbar (or very near the critical pressure), the message DEWT/BUBT COULD NOT LOCATE THE PHASE BOUNDARY is given, and calculations are made at an extrapolated temperature. If only one component is given, saturation values are found. For a pure component, the SATF option may also be used to find phase boundary information.
DIR command enables you to see the contents of any directory or subdirectory. After entering the DIR command you will be prompted for the directory. For example, if you have a subdirectory whose path is c:\dos\work, entering that pathname will display the directory in wide format. Entering a carriage return in response to the prompt will produce the contents of your current directory. NOTE: If you encounter problems with this command, you may have to increase your FILES= statement in the CONFIG.SYS file.
The EDIT option allows you to change the feed composition of a single component selectively, leaving the others unchanged. The EDIT utility is available whether mass or molar input has been specified and whether absolute or fractional compositions are specified. This EDIT option is particularly useful for the case where you are entering mole fractions and have made a typing mistake that causes the overall composition not to sum to unity. When this happens, you will automatically be placed into EDIT mode. Otherwise, type EDIT at the command line. To leave the edit loop, type a carriage return or an X. A sample edit loop is shown below. Note that you may either enter the full component name or its synonym as given in Appendix C.
The FEED command enables you to change the concentrations all of the components in the mixture. If you enter FEED, you will then be prompted for the new concentration of each component. Depending on the selected options, you will be prompted to enter mole fraction, number of moles, mass fraction, or number of grams for each component of the mixture.
An isothermal flash calculation finds the quantities and compositions of the phases in equilibrium at a given pressure, temperature and overall composition. The isothermal flash is the default command at the command line in NIST14. 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. Two sample FLTP screens are shown below: the first type results if a molar composition has been specified and the second sample output is generated when a mass composition has been specified. (Because the two feeds are not equivalent, the output states and properties are not equivalent.) The program is designed to operate within the range 54-1000 K and 0-300 MPa. An error message is given for points outside of this range and such a point is then ignored.
If a molar input has previously been specified:
If a mass input has previously been specified:
The compositions of the phases present are given, along with the "Kvalue", which is the ratio of the vapor phase molar composition of a component to the liquid phase molar composition of that component. The amounts of each component are given as mole fractions or mass fractions depending on the input used. The relative quantities of the phases present are given in the line labeled feed fraction. For the first example shown, if there is 1 mole of feed, the flash calculation gives 0.906431 mol of liquid and 0.0935693 mol of vapor. For the second example shown, if there is 1 gram of feed, the flash calculation shows 0.607093 g of liquid and 0.392907 g of vapor. The properties of each phase present, including the molecular weights, compressibility factor (defined as z=PV/RT), density, enthalpy, entropy, Cp, Cp/Cv, sound speed and the Joule-Thomson coefficient, as well as transport properties (viscosity, thermal conductivity) are displayed as output in the appropriate column.
The feed values represent appropriate phase-averaged quantities (for molecular weight, compressibility factor, and density) or total system values (appropriate sum of liquid and vapor values) for extensive quantities (enthalpy, entropy, and isobaric heat capacity). Note that the feed in these calculations need not represent a state in thermodynamic equilibrium. We follow the conventional feed definitions in our determination of feed properties at the specified temperature, pressure, and input composition.
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: a single liquid phase, vapor phase, or supercritical vapor phase may be present.) The NIST14 program labels the phases present and gives properties of the phases, calculated with the NIST Extended Corresponding States model with exact shape factors and empirical binary interaction parameters. The phase equilibrium is always done with the Peng-Robinson model.
The KIJ command enables you to change, or simply view, the interaction parameters for each binary pair in the mixture within the NIST Extended Corresponding States model. For most of the binary interactions within the NIST14 Database, the interaction parameters have been regressed from available data. However, they can be changed 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 in adjusting them. When you enter KIJ, you will be shown the current values of kij and lij for each of the possible binary combinations of the mixture components and you will be prompted to enter 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. To view kij and lij, but not change them, type a carriage return 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.
KIJV allows you to change, or simply view, the PRS (Peng-Robinson) interaction parameters which are used for the phase equilibrium calculations. The NIST Extended Corresponding States parameters, used to calculate properties within each phase, are not altered when KIJV is invoked. The phase equilibrium tends to be very sensitive to the KIJV interaction parameters, so care should be used in adjusting them. Upon invoking the KIJV command, you will be 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 stores default values of Peng-Robinson binary interaction parameters which were found by examining data for each available pair of components. To view the kijv, but not change them, type a carriage return 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.
The command MASSIN allows you to toggle the input and output modes between molar and mass options. If a previous composition was entered as a mole fraction, for example, entering MASSIN will result in a prompt for entering the composition in grams or as mass fractions. The output compositions and feed fractions are always given on the same basis as specified in the composition input.
You have the option of entering a feed composition such that the mole fractions or mass fractions sum to unity, or you can have the program normalize your input feed composition. NORMAL enables you to switch back and forth between the mole fraction input and the molar input modes or between mass fraction input and mass input. You can tell which mode you are in by the prompt when you are entering a composition.
This command allows the user to open a new input or output file. You will be asked whether an input or output file is desired; enter the word INPUT or OUTPUT in response to this query.
NOTE: If problems are encountered with this command, it may be necessary to increase the FILES= statement in your CONFIG.SYS file.
PRINT enables you to list a file on the printer [PRN] device. Any ASCII file may be printed. If you request that the current output file be printed, it will be closed and then reopened to flush the buffer. If you request that a file other than the output file be printed, the current output file (if any) will remain unchanged.
The RESET command starts the NIST14 Database from the beginning. (Specifications concerning input modes, interaction parameters, etc. are returned to the default settings.)
SATF allows you to calculate saturation thermodynamic properties of the pure components in the mixture for a specified temperature. 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 transport properties are desired or if pressure input is desired, you may run the DEWP, DEWT, BUBP, or BUBT options using a pure fluid to get saturation values.) To perform the calculation, enter SATF at the command line. You will be prompted for the temperature and the results will be displayed on the screen.
Terminate SATF with a carriage return or X. A sample SATF screen is given below.
The SLATE command enables you to change the components in the mixture. You will first be asked to enter the number of components in the new mixture. The NIST Mixture Property Database can currently handle mixtures of up to seventeen components. If you enter a "0" (zero) response for the number of components, the program will stop. If you enter a positive integer less than 18, you will be prompted for the names of the components. A question mark (?) at the "Enter name the component" prompt, will result in a listing of the available component library. The component names and synonyms supplied in NIST14 are given in Appendix C. After the component names have been entered, you will be asked to enter new compositional information for the mixture.
This command terminates execution of the program and returns you to the operating system prompt. The program can also be terminated at any point by entering the CTRL-C command, or by entering STOP, QUIT, END, or BYE in response to any yes/no interactive query.
SYSTEM enables you to execute an MS/PC-DOS command from within NIST14. After entering SYSTEM you will be prompted for the system command. The total command length must be less than 77 characters. For example, if you enter the phrase >current.dir dir c:\dos, the directory of c:\dos will be placed in the file current.dir which can then be manipulated by NIST14 or by using other system commands (e.g., invoking an editor with the system command).
The TABLE option allows you to generate a table, or a series of tables, of results along isotherms or isobars. The compositions of coexisting phases are not tabulated due to a lack of space, although the coexisting phase properties such as density, enthalpy, entropy, etc., are given. If the range of conditions specified intersects a two-phase region, compositions can be obtained by performing an isothermal flash calculation when the TABLE option has completed its execution. The transport properties are also not tabulated. You will be asked if you wish to generate a table with either the temperature varying at constant pressure or pressure varying at constant temperature. (You may also change the units at this time by typing UNITS, or you may return to the main command prompt by typing an X or a carriage return). You next will be asked to enter the minimum, maximum and incremental values for the variables.
NIST14 assumes that you want to save the table on a file for later use. You will be asked to enter a file name. If you are currently saving the output on a file and want the table to go on that file, enter that output file name. You can also enter the name of any other file. If you enter a carriage return, the null file is assumed. You also will be asked if you want to see the table simultaneously on the screen as it is generated. Short sample tables for a C2, C3, C4 mixture are shown below. In this example, we have indicated two-phase points with an asterisk (although the program output does not produce the asterisk). For the two-phase points, note that the first line represents the liquid phase properties, and the second line (printed with a blank in the first column) gives vapor properties.
TYPE enables you to list a file on the screen. Any ASCII file may be typed. If you request the current output file to be typed it will be closed and then reopened to flush the buffer. If you request that a file other than the output file be typed, the current output file (if any) will remain unchanged.
You can select from various input/output unit combinations in the NIST14 Database. This command will place you in a menu-driven unit selection routine. The current units (in the right-hand column) and the unit options are given on the menu, as shown below. You can change a specific unit by entering the new unit you want. For example, if you wish the pressure to be in megapascals enter MPA. You can also select one of four "default" sets of units by entering a number between 1 and 4. To exit, enter an X. You can also enter several units on one line and exit; e.g.,
MPA,CAL,X
will select pressures in MPa, energies in cal and exit.
Input files may be used to direct program execution as an alternative to entering data from the terminal keyboard. If you open an input file, either in answer to the initial program query or using the OPEN command with "input" option, the program will take information from the specified file until an end-of-file or $END is encountered. Note that upper case ASCII characters are required when specifying component names or synonyms, but lower case is allowed to specify command options. The format of each line should conform to the specifications outlined in this section.
A sample file which could be used as input to the NIST14 Database is given below.
This guide is meant to be a user manual, and not a detailed description of the various methods used in the program. The interested user may find the following publications useful references on the various technical aspects of the NIST14 Database program.
1. General References for Database
James F. Ely, Joe W. Magee, and William M. Haynes, "Thermophysical Properties for Special High CO2 Content Mixtures", Research Report RR-110, Gas Processors Association, Tulsa, Oklahoma, 1987.
James F. Ely, "An Equation of State Model for Pure CO2 and CO2 Rich Mixtures", Proc. 65th Annual Convention, Gas Processors Association, Tulsa, Oklahoma, 1986.
James F. Ely, "A Predictive, Exact Shape Factor Extended Corresponding States Model for Mixtures," Adv. Cryo. Engin., 35, 511-520, 1990.
2. Pure Fluid Reference Data
Younglove, B.A., "Thermophysical Properties of Fluids. I. Argon, ethylene, parahydrogen, nitrogen, nitrogen trifluoride, and oxygen," J. Phys. Chem. Ref. Data 11, Suppl. No. 1, 1982.
Younglove, B.A. and Ely, J.F., "Thermophysical Properties of Fluids. II. Methane, Ethane, Propane, Isobutane, and Normal Butane," J. Phys. Chem. Ref. Data 16, 577-798, 1987.
3. Corresponding States Method
Leach, J. W., Chappelear, P. S. and Leland, T. W., "Use of molecular shape factors in vapor-liquid equilibrium calculations with the corresponding states principle", AIChE J., 14: 568-576 (1968).
Leland, T. W., Chappelear, P. S. and Gammon, B. W., "Prediction of vapor-liquid equilibria from the corresponding states principle", AIChE J., 8: 482-489, (1962).
Leland, T. W. and Chappelear, P. S., "The corresponding states principle. A review of current theory and practice", I&EC Fund., 60: 15-43, (1968).
Fisher, G. D. and Leland, T. W. "The corresponding states principle using shape factors", I&EC Fund., 9: 537-544 (1970).
4. Transport Property Prediction
Ely, J.F., "An Enskog Correction for Size and Mass Difference Effects in Mixture Viscosity Prediction", J. Research NBS, 86, No. 6, 597-603 (1981).
Ely, J.F. and Hanley, H.J.M., "Prediction of Transport Properties. 1. Viscosity of Fluids and Mixtures", I&EC Fund., 20, No. 4, 323-332, (1981).
Ely, J.F. and Hanley, H.J.M., "Prediction of Transport Properties. 2. Thermal Conductivity of Pure Fluids and Mixtures", I&EC Fund., 22, No. 1, 90-97 (1983).
5. Peng-Robinson Equation of State
Peng, D.Y. and Robinson, D.B., "A new Two-Constant Equation of State", I&EC Fund., 15, 59-64 (1976).
NOMENCLATURE
BUBP: Bubble point pressure calculation
BUBT: Bubble point temperature calculation
CLOSE: Close the output file
COMP: Specify composition; file input only
DEWP: Dew point pressure calculation
DEWT: Dew point temperature calculation
DIR: Obtain the directory that is associated with a pathname
EDIT: Edit the feed composition
FEED: Change the composition
FLTP: Isothermal flash calculation (default)
KIJ: Change Extended Corresponding States (EXCST) interaction parameters
KIJV: Change the vapor-liquid equilibrium (VLE) interaction parameters
LIJ: Change Extended Corresponding States (EXCST) size-related parameter; file input only
MASSIN: Toggle the mass/mole input/output mode
MASS: Same as MASSIN; file input only
NORMAL: Toggle the composition mode
NORM: Same as NORMAL; file input only
OPEN: Open a new input or output file
PRINT: Print file on printer
REF: References or remarks to follow; file input only
RESET: Restart NIST14
SATF: Pure component saturation properties
SLATE: Change the components in the mixture
STOP: Terminate the program
SYSTEM: Execute a system command
TABLE: Generate a table
TYPE: List a file on screen
UNITS: Change the current units
$END: End of file marker; file input only
Comp. Factor: compressibility factor, PV/RT
Cp: heat capacity at constant pressure
Cp/Cv: ratio of heat capacity at constant pressure to heat capacity at constant volume
D: density
Dsat,L; D(liq): saturated liquid density
Dsat,V; D(Vap): saturated vapor density
EXCST: NIST Extended Corresponding States model
f/P: fugacity coefficient divided by pressure
H: enthalpy
H(v)-H(l): heat of vaporization
JT: Joule-Thomson coefficient
Kvalue: ratio of vapor phase molar composition of a component to the liquid phase molar composition of that component
MW: molecular weight or molar mass
P: pressure
Phi: fugacity coefficient of component divided by pressure
PRS: Peng-Robinson equation of state model
Psat: saturation pressure
S: entropy
T: temperature
Therm.Cond.; TC: thermal conductivity
T(crt): critical temperature
T(trp): triple point temperature
uP: micropoise (P)
V: volume
Visc.: viscosity
VLE: vapor-liquid equilibrium
Z: compressibility factor, PV/RT
_____________
name: synonym
____________
METHANE: C1
ARGON: AR
ETHANE: C2
NITROGEN: N2
ETHYLENE: C2-
OXYGEN: O2
PROPANE: C3
CARBON MONOXIDE: CO
N-BUTANE: C4
CARBON DIOXIDE: CO2
I-BUTANE: IC4
HYDROGEN SULFIDE: H2S
N-PENTANE: C5
I-PENTANE: IC5
N-HEXANE: C6
I-HEXANE: IC6
N-HEPTANE: C7
density
molecular weight (molar mass)
compressibility factor
enthalpy
entropy
composition (mole or mass fraction of coexisting phases)
Cp (heat capacity at constant pressure)
Cp/Cv (heat capacity at constant pressure/heat capacity at constant volume)
feed fraction (amount of each phase on a molar or mass basis)
sound speed
Joule-Thomson coefficient
viscosity
thermal conductivity
If you have comments or questions about the database, the Standard Reference Data Program would like to hear from you. Also, if you should have any problems with the diskettes or installation, please let us know by contacting: