VLMU.BAS is the BASIC language program for mixture calculations
using the
Peng-Robinson equation of state discussed in Chapter 7, and especially in
Appendix A7.2, of the second edition of "Chemical and Engineering
Thermodynamics" by Stanley I. Sandler. This program can be used to
calculate
densities, fugacities, dew point temperatures or pressures, bubble point
temperatures or pressures, or to do an isothermal flash calculation. For
any
phase equilibrium calculation, the compositions and properties of the
coexisting phases are reported. The flow of the program is described in
Appendix A7.2.
The critical temperature, critical pressure, acentric factor and
normal
boiling temperature for each substance in the mixture are needed to use
this
program. These data for many substances are given in Table 4.6-1. In
addition, you will need the binary interaction parameter for each pair of
components in the mixture. The interaction parameters for many binary
pairs
can be found in Table 7.4-1. This information should be gathered before
using
the program.
When running the program, you will be prompted to provide the
information indicated above. When several items of data are requested at
once
(for example, TC, PC, w, and Tboil), type them on a single line separated
by
commas. If you enter the property information from the keyboard, you
will be
prompted to name the file in which this information will be stored. This
file
may be used to rerun the program with the same components. CO2&NC4.DAT,
which
contains the property information for the binary mixture of carbon
dioxide and
n-butane, is an example of such a file. The binary interaction
parameters are
not stored in the data file, so that the program can be rerun with the
same
mixture but different values of the binary interaction parameter.
The results of all calculations are displayed on the screen, but are
not
stored. Therefore, you should be prepared to either write the results of
the
calculations on paper or, if a printer is attached to your computer,
print the
contents of the screen (by pressing the shifted key PrtSc). You may also
have
the results printed by replacing the word PRINT in the output statements
with
LPRINT. Alternatively, by simultaneously pressing the Ctrl and PrtSc
keys,
everything that appears on the screen will also be sent to the printer
until
the Ctrl and PrtSc keys are pressed again.
To run VLMU.BAS, you must first load it into BASICA. If you are
unfamiliar with how to do this, it is suggested that you use the
following
procedure. First make drive A the default drive by typing A:[enter] at
the
DOS > prompt. Next put a disk containing advanced BASIC (i.e., IBM
BASICA) in
drive A and type BASICA [enter]. After BASICA is loaded, remove the disk
from
drive A, insert this disk, and then type LOAD "A:VLMU.BAS"[enter]. After
the
OK response, type RUN [enter].
This program will run much faster if it is compiled using a BASIC
compiler. If you choose to do this and use a compiler that provides
compilation options (such as QuickBASIC by Microsoft), include the Event
Trapping and Checking Between Statements options. All BASIC compilers
are
different, so you will need to consult the documentation for your
compiler to
determine how to compile this program which is in ASCII format on this
disk.