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1991-09-05
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$CREST HELP FILE
GENERAL HELP INFORMATION
CREST: Chemical Reactions and Equilibrium Statistical Thermodynamics
------------------------- selected keywords ------------------------
COMPOUND DATA DISSOCIATION ELEMENT ENTHALPY
ENTROPY ERROR GIBBS MENU REACTION
SPECIFIC HEAT SPOOL STOP SYMBOLS SYNTAX
--------------------------------------------------------------------
enter ?,keyword for help (e.g. ?,ELEMENT)
enter ?,error number for advice (e.g. ?,12)
If you have any other questions give me a call at 615-632-1887.
To leave help and return to menu just hit Enter
$tap the spacebar or click the mouse to proceed
*
COMPOUND
CREST allows you to define your own compounds. Each must be identified
by a unique 12-character symbol. The first character of the symbol
must be an upper case letter (A-Z) and the rest can either be a lower
case letter (a-z), or a blank (e.g. Hd, Ss, Wa), or any one of the
following "#$%&:;@^`{|}~, (e.g. Hydroxl*, Ca:, Cl$$). You can not use
numbers or parentheses (e.g. H2 is two moles of H, not diatomic
hydrogen, use something like Hdia for diatomic hydrogen). The elements
must be set-off by [].
You might define coal using the following symbols:
Coal[C.2H.75S.05]
this would be "Coal" means coal and it is composed of 20% C, 75% H, and
5% S (mole fraction).
"COAL[etc.]" is not permissible because there is no way of
distinguishing this from 1 mole of C and 1 mole of O etc.
Carbon monoxide as a compound could be defined as:
Cmonox[CO]
MEK (methyl-ethyl-ketone) could be defined by any of the following:
Mek[CH3 CO C2H5]
Mek[CHHHCOCCHHHHH]
Mek[C4H8O]
$tap the spacebar or click the mouse to proceed
*
DATA
You must specify the elements, compounds, and reaction in a data file.
You can have as many data files as you like, so there is no limit to
how many reactions which can be analyzed.
All of the elements and compounds which appear in a reaction must be
defined in a file before reading the input file containing the reaction
to be solved.
The default data file name is CREST.GAS. If you want to specify some
other data file do so in the runtime string as illustrated below:
CREST DATABASE=MYDATA.DAT
A file named CREST.AQU containing the properties of various aqueous
substances is also provided.
$tap the spacebar or click the mouse to proceed
*
DISSOCIATION
To compute dissociation try something like...
Cdiox=C+O+Odia+Cmonox+Cdiox
Water=Water+H+Hdia+Hydroxl+O+Odia
$tap the spacebar or click the mouse to proceed
*
ELEMENT
CREST allows you to define your own elements or isotopes. Each must be
identified by a unique 12-character symbol. The first character of the
symbol must be an upper case letter (A-Z) and the rest can either be a
lower case letter (a-z), or a blank (e.g. Hd, Ss, Wa), or any one of
the following "#$%&:;@^`{|}~, (e.g. Hydroxl*, Ca:, Cl$$). You can not
use numbers or parentheses (e.g. H2 is not an element).
$tap the spacebar or click the mouse to proceed
*
ENTROPY
ENTHALPY
Enthalpy is in Btu/lb-mole and is referenced to standard temperature
and pressure, STP (which is 1 atm. or 14.696 psia and 537R/25C). The
enthalpy listed includes the enthalpy of formation.
The enthalpy of formation must be specified in the data file for each
element and compound.
Entropy is in Btu/lb-mole/R and is referenced to absolute zero and
standard pressure (which is 1 atm or 14.696 psia). The entropy listed
includes the entropy at STP.
The entropy at STP must be specified in the data file for each element
and compound.
$tap the spacebar or click the mouse to proceed
*
GIBBS
The Gibbs free energy is in Btu/lb-mole and is referenced to standard
temperature and pressure, STP (which is 1 atm. or 14.696 psia and
537R/25C). The free energy listed includes the energy of formation.
$tap the spacebar or click the mouse to proceed
*
HELP
You're pretty bad off, confused huh? Why not give me a call.
$tap the spacebar or click the mouse to proceed
*
MENU
if you want to get back to the menu, just hit Enter
$tap the spacebar or click the mouse to proceed
*
METHOD
One of the important applications of chemical equilibrium analysis is
to determine dissociation. Usually this requires specifying each of
the dissociation reactions separately. This is not necessary with
CREST. Actually, I've always found this a pain. The reason this is
done in most chemical reaction analyses is that the theory was
developed for hand calculations and graphical solutions before the days
of the computer. The "K" formulation while analytically elegant, is
cumbersome and inefficient when a computer is available. Furthermore,
the "K" method when computerized is inherently unstable.
I solve simultaneously the elemental abundance conditions (viz. the
conservation of species), the conservation of energy (viz. the First
Law of Thermodynamics), and the Gibbs condition (viz. the Second Law
of Thermodynamics). The algorithm used is a variation of the RAND
method as presented by W. B. White, S. M. Johnson, and G. B.
Dantzig in "Chemical Equilibrium in Complex Mixtures," The Journal of
Chemical Physics, 28:5:751-5, 1958.
$tap the spacebar or click the mouse to proceed
*
PLOT
If CREST can't run TPLOT for you because of insufficient memory, then
you can always exit CREST and run TPLOT externally (from DOS). The
plot commands will be saved in CREST.PLT and the data in file
CREST.OUT. To run TPLOT enter:
TPLOT CREST.PLT
You can edit the command file, CREST.PLT, or override the device by
using the following syntax:
you type this command for this device
TPLOT LU=8086 CREST.PLT CGA (320X200)
TPLOT LU=8088 CREST.PLT CGA (640X200)
TPLOT LU=186 CREST.PLT HGA (Hercules)
TPLOT LU=286 CREST.PLT EGA
TPLOT LU=386 CREST.PLT QGA (Compaq Plasma)
TPLOT LU=486 CREST.PLT VGA
TPLOT LU=7240 CREST.PLT HP-7240
TPLOT LU=7470 PORT=1 CREST.PLT HP-7470
TPLOT LU=7475 PORT=1 CREST.PLT HP-7475
TPLOT LU=7550 PORT=1 CREST.PLT HP-7550
NOTE: the LU numbers (e.g. 8086,286,386...) have nothing whatsoever to
do with what processor you have. I had to pick something and
these just happened to be the processors that I had at the time I
was using each of the above graphics adaptors.
Substitute PORT=2 in the above commands if the device is connected to
COM1. If you must translate for a dot matrix printer or LaserJet use
the following:
ERASE TPLOT.OUT
TPLOT LU=7550 BINARY CREST.PLT TPLOT.OUT
HPGL2PRN LASERJET TPLOT.OUT BINARY
ERASE TPLOT.OUT
You can substitute Star, IBM, or Epson for LaserJet in the above
expression (upper or lower case doesn't matter). If you have a Star,
IBM, or Epson you may also want to add DOUBLE after TPLOT.OUT for your
final copy.
$tap the spacebar or click the mouse to proceed
*
REACTION
There can only be 1 reaction; but it can have many reactants and
products. If you have more than 1 reaction in the data file, CREST
will read the first and ignore the rest. If you want to analyze more
than 1 reaction, you can keep several data files or just comment out
the ones you don't want by putting an asterisk "*" in column 1.
The reaction is defined by a group of elements and/or compounds
followed by a "=" and another group of elements and/or compounds. The
first group is the reactants and the second is the products.
The mole fractions of the reactants must be specified. This is done by
preceding the element/compound with a number (which may be a decimal
fraction). The mole fraction of the products must not be specified
(determination of the mole fraction of the products is the reason for
CREST in the first place).
An example of correct reaction syntax is as follows:
Benzene+3Odia+7Ndia=Cdiox+Cmonox+C+O+H+Water+Hydroxl+Hdia+N+Nmonox+
Ndiox
where Benzene is benzene
Odia is O2 (diatomic oxygen)
Ndia is N2 (diatomic nitrogen)
Cdiox is CO2 (carbon dioxide)
Cmonox is CO (carbon monoxide)
Water is H2O
Hydroxl is HO
Hdia is H2 (diatomic hydrogen)
Nmonox is NO (monotomic nitrogen)
Ndiox is NO2 (nitrogen dioxide)
$tap the spacebar or click the mouse to proceed
*
REFERENCE
The reference for enthalpy and Gibbs free energy is STP (537R/25C and 1
atm. or 14.696 psia). The reference for entropy is absolute zero
temperature and 1 atm. This is the convention, although it doesn't
really matter as long as you are consistent. I'd prefer to use
absolute zero for both; but then no one asked me.
$tap the spacebar or click the mouse to proceed
*
SPECIFIC HEAT
Specific heat of each element and compound must be specified in the
data file. The specific heat must be curve-fitted to the equation:
Cp=C1+C2*T+C3*T**2
For constant specific heat only C1 need be specified.
$tap the spacebar or click the mouse to proceed
*
SYMBOLS
Elements and compounds are identified by 12 character symbols. Each
must be unique. CREST distinguishes between elements and compounds by
storing the symbols in two separate lists when it reads them from the
data file. A symbol must begin with an upper case letter followed by
either blanks or a lower case letters. Some examples are as follows:
correct incorrect
N N2
S SS
Na NA
Coal COAL
Air air
$tap the spacebar or click the mouse to proceed
*
SYNTAX
Syntax is very important. Computers have a nasty habit of doing what
you tell them to, not necessarily what you want them to do. "Close"
just won't do. There is a reason for the syntax that I have selected,
while it is not the only possible syntax, it is self-consistent,
straightforward, and unambiguous. It is also easily recognizable. For
instance, I have not allowed parentheses in the syntax. While this is
a common practice in chemistry is it a real pain to interpret. The
following are NOT allowed:
Ca3(PO4)2 Na(NH4)2(Co(NO2)6) (Hg2)3(Fe(CN)6)2
For more help on syntax try ?,REA or ?,COM or ?,ELE
$tap the spacebar or click the mouse to proceed
*
SPOOL
FILE
PRINT
PRN
LPT
OUTPUT
If you want to divert the output of CREST from the printer to a file,
specify one in the runtime string as illustrated below:
CREST SPOOL=MYFILE.OUT
If you also have a data file specify both as illustrated below:
CREST DATABASE=MYDATA.DAT SPOOL=MYFILE.OUT
The output file must not previously exist.
$tap the spacebar or click the mouse to proceed
*
STOP
if you want to stop, just hit Enter twice
$tap the spacebar or click the mouse to proceed
*
************************************************************************
*
1
ERROR#1: read error
You may have typed something in wrong, file is
corrupt, or any other problem which would
result in a file read error.
$tap the spacebar or click the mouse to proceed
*
2
ERROR#2: syntax error
This may be due to incorrect characters, use
of parentheses, misplaced +,=,[,] sign etc. A
syntax error will also occur if something like
the following is found: "++", "+!", or "2!H".
$tap the spacebar or click the mouse to proceed
*
3
ERROR#3: reaction has only one reactant and only one product
There isn't a reaction to solve.
$tap the spacebar or click the mouse to proceed
*
4
ERROR#4: element does not appear on both sides of reaction
This error occurs if an element appears on the left side
of a reaction then it must also appear on the right side
and vise versa.
$tap the spacebar or click the mouse to proceed
*
5
ERROR#5: reaction has no products
This can be due to a missing "=" sign or nothing
on the right hand side of the reaction.
$tap the spacebar or click the mouse to proceed
*
6
ERROR#6: unexpected EOF (end of file)
CREST was looking for something else and
didn't find it before encountering the end of
data. Sometimes this error occurs when your
reaction has no "=" sign in it or you have not
specified a reaction.
$tap the spacebar or click the mouse to proceed
*
7
ERROR#7: too many elements (max=32)
$tap the spacebar or click the mouse to proceed
*
8
ERROR#8: redundant reactant/product
The more than one occurrence of the same
substance was found on the same side of the
reaction, for example Air+Coal+Air=etc...
$tap the spacebar or click the mouse to proceed
*
9
ERROR#9: too many compounds (max=128)
$tap the spacebar or click the mouse to proceed
*
10
ERROR#10: reaction has no reactants
This can be due to an extra "=" sign or nothing
on the left hand side of the reaction.
$tap the spacebar or click the mouse to proceed
*
11
ERROR#11: undefined substance
Every substance in the reaction must appear in
the database as either an element or a compound.
$tap the spacebar or click the mouse to proceed
*
12
ERROR#12: unable to access database
This can be due to it not existing (e.g., you
spelled it wrong), not accessible (e.g., hidden
or locked), too many files, or bad PATH=
environment variable.
$tap the spacebar or click the mouse to proceed
*
13
ERROR#13: compound contains no elements
Each compound name in the database must be
followed with the elements which comprise the
compound. These must be contained within
brackets [].
$tap the spacebar or click the mouse to proceed
*
14
ERROR#14: undefined mole fraction
You may have improper syntax resulting in
CREST interpreting a negative or zero mole
fraction.
$tap the spacebar or click the mouse to proceed
*
15
ERROR#15: unable to access data file
Either the file does not exist, you typed the
name in wrong, the disk drive is down, or the
file is read protected.
$tap the spacebar or click the mouse to proceed
*
16
ERROR#16: reaction equations unstable
This may be due to an "ill posed" reaction,
extreme temperature or pressure limits, or
unreasonable specific heats.
$tap the spacebar or click the mouse to proceed
*
17
ERROR#17: illegal file name
You cannot use spool or reaction filenames
that begin with either CREST or TPLOT. You
can use data files that begin with either. In
any case, never use a filename of TPLOT.OUT as
this will be destroyed by any graphics
operations.
$tap the spacebar or click the mouse to proceed
*
18
ERROR#18: compound contains too many elements (max=16)
$tap the spacebar or click the mouse to proceed
*
19
ERROR#19: reaction contains too many reactants (max=128)
$tap the spacebar or click the mouse to proceed
*
20
ERROR#20: reaction contains too many products (max=128)
$tap the spacebar or click the mouse to proceed
*
21
ERROR#21: break detected
You must have hit a key while processing was
in progress.
$tap the spacebar or click the mouse to proceed
*
22
ERROR#22: reaction contains no elements
$tap the spacebar or click the mouse to proceed
*
23
ERROR#23: reaction contains no compounds
$tap the spacebar or click the mouse to proceed
*
24
ERROR#24: more than 128 simultaneous equations
The total number of simultaneous equations that must be
solved in order to determine equilibrium is equal to the
number of elements plus the number of products. The number
of elements adds to this total; because conservation of
these constitutes linear constraints which are implemented
using Lagrange multipliers. A 128x128 matrix of single
precision (REAL*4) variables is accessible through large
memory addressing. Anything bigger than this requires huge
memory addressing and greatly increases the overhead and
subsequent runtime. For this reason, I don't even make this
an option. You will just have to make do with 128.
$tap the spacebar or click the mouse to proceed
*
25
ERROR#25: unable to open plot data file CREST.OUT
$tap the spacebar or click the mouse to proceed
*
26
ERROR#26: write error involving plot data file CREST.OUT
$tap the spacebar or click the mouse to proceed
*
27
ERROR#27: unable to open plot command file CREST.PLT
$tap the spacebar or click the mouse to proceed
*
28
ERROR#28: write error involving plot command file CREST.PLT
$tap the spacebar or click the mouse to proceed
*
29
ERROR#29: illegal video mode... may be a hardware incompatibility
Your CRT should be in CGA or monochrome mode depending on the
hardware. Try setting the mode to "MODE CO80" if it is a CGA.
If you have a CGA plasma or LCD display and can't tell the
highlighted or color lines from each other, then try setting it
to "MODE BW80".
$tap the spacebar or click the mouse to proceed
*
30
ERROR#30: insufficient available memory
In order to solve the equations it is
necessary to allocate a considerable amount of
memory. Your machine does not have sufficient
available memory to process the request.
Either solve a smaller reaction or find
another machine.
$tap the spacebar or click the mouse to proceed
*
31
ERROR#31: substance element/compound ambiguity
This error will occur if a substance which
appears in the reaction is found in the
database as a compound and appears in itself
or some other compound as an element.
$tap the spacebar or click the mouse to proceed
*
32
ERROR#32: undefined state code
The state code must be 0-5 which indicates
respectively the following states: unknown,
gas, gaseous ion, aqueous ion, liquid, or
dispersed solid. CREST does not handle
precipitated solids which have a vanishing
fugacity.
$tap the spacebar or click the mouse to proceed
*
************************************************************************
*
CAN'T_CREATE_FILE
Unable to create or access file. This can be
due to a number of factors including illegal
name and no such path or drive.
$tap the spacebar or click the mouse to proceed
*
CAN'T_FIND_DATABASE
Can't find database file. Either the file
doesn't exist or it can't be located. This
may be a result of a bad PATH= environment
string. CREST must have a database from which
to extract compositions and properties. You
must supply a name. Two database files should
have come with CREST: CREST.GAS and CREST.AQU.
The default database is CREST.GAS.
$tap the spacebar or click the mouse to proceed
*
CAN'T_FIND_REACTION
Can't find reaction file. Either the file
doesn't exist or it can't be located. This may
be a result of a bad PATH= environment string.
$tap the spacebar or click the mouse to proceed
*
CAN'T_OPEN_DATABASE
Unable to open or access database file. This
can be due to a number of factors including no
such file, illegal name, and no such path or
drive. CREST must have a database from which
to extract compositions and properties. You
must supply a name. Two database files should
have come with CREST: CREST.GAS and CREST.GAS.
The default database is CREST.GAS.
$tap the spacebar or click the mouse to proceed
*
CAN'T_OPEN_REACTION
Unable to open or access reaction file. This can
be due to a number of factors including no such
file, illegal name, and no such path or drive.
$tap the spacebar or click the mouse to proceed
*
EDIT_REACTION
You can use all of the usual full screen edit
keys as well as alt-C to copy a line, alt-D to
delete a line, and alt-I to insert a line.
Press F1 to list the substances in the current
database. When you are done press F10.
$tap the spacebar or click the mouse to proceed
*
FILE_ALREADY_EXISTS
The file you have selected already exists.
?Are you sure you want to overwrite it?(Y/N)
*
MAIN_MENU
Compute properties --> compute U,H,S,G for a given T,P
Database ------------> select another or list current database
Edit reaction -------> display or modify the reaction
File reaction -------> save the current reaction in a disk file
Graph ---------------> solve a series of reactions and plot results
Print=ON/OFF --------> begin/quit listing results to printer
Read reaction -------> open existing disk file and read contents
Solve reaction ------> determine equilibrium composition of products
Units=English/SI ----> select units for input/output
$tap the spacebar or click the mouse to proceed
*
NO_DATABASE
Database name is null. CREST must have the name of
a database from which to extract compositions and
properties. You must supply a name. Two database
files should have come with CREST: CREST.GAS and
CREST.AQU. The default database is CREST.GAS.
$tap the spacebar or click the mouse to proceed
*
NULL_REACTION
Either the file is empty or there is no reaction in it.
$tap the spacebar or click the mouse to proceed
*
PLOT_DEVICE
You must select a device on which to display the plot. Of
course, it should go without saying that you shouldn't
select one that you don't have connected to your system.
You can display the plot on the CRT and request a PrtSc if
your hard copy device does not appear in the list--provided
that you have the proper driver installed (you should have
done this before successfully before). If you use the PrtSc
to produce a hard copy you will be severely limited in
resolution (a plot produced on a dot matrix or LaserJet
printer will look much better than what you would get using
PrtSc).
$tap the spacebar or click the mouse to proceed
*
REACTION_UNDEFINED
The reaction is not defined. Either there is no
reaction, it has some error (e.g., no reactants, no
products, too many of something), or the properties
cannot be found in the database.
$tap the spacebar or click the mouse to proceed
*
RESERVED_NAME
You cannot use spool or reaction filenames that
begin with either CREST or TPLOT. You can use data
files that begin with either. In any case, never
use a filename of TPLOT.OUT as this will be
destroyed by any graphics operations.
$tap the spacebar or click the mouse to proceed
*
TOO_MANY_CHARACTERS
There are too many characters on a line in the data
file. This is limited to 78 in order to be able to
edit it. You must use some other means such as a
text editor or word processor to edit the file and
confine the data to 78 columns.
$tap the spacebar or click the mouse to proceed
*
TOO_MANY_LINES
There are too many lines in the reaction file. This
is limited to 50 in order to be able to edit it.
You must use some other means such as a text editor
or word processor to edit the file and confine the
data to 50 lines.
$tap the spacebar or click the mouse to proceed
