The interest in the Prode Properties-Mathcad combination is heating up, so I am taking a pause in the kinetic modeling series for this entry.
I've only been working with Prode Physical Properties (PPP) for a short time, but I have some observations that may be of help to those just starting with the program.
Some information can be obtained from the PPP database without the need for a stream, but in general, at least one stream needs to be generated in the PPP window and archive. Streams can be created manually using the PPP window, or they can be created using a series of PPP functions. I prefer to use the manual method because it is easier to set the thermodynamic models in the window than with the command functions. The latter involves setting several bits in a register variable and it can be a little difficult to master. The Prode Properties manual shows how to create streams by both methods and my test file shows the command function method.
Getting component identifications
Once you have a stream built with the components you need for your Mathcad model, it is easy to get the component numbers, names and formulas as shown below. This is a check on the components you selected as well as documentation for your Mathcad program.
Getting basic thermodynamic properties
Once you have the component numbers (ccode vector in this example), you can obtain the pure component data needed, such as molecular weight, heat of formation, and free energy of formation.
When a value is obtained from PPP, the SI units are assumed. In order to use the Mathcad unit tracking and conversion capabilities, the retrieved variable (which has no explicit units) must be multiplied by the appropriate SI unit.
Many of my references are in kcal/mol, so I have shown the results in those units for the heats and free energies of formation. This meant I had to multiply the values from PPP by the molecular weight to obtain values on a molar basis. This example shows how easy it is to incorporate the PPP properties in SI units into the Mathcad system and use whatever units you desire.
Once you have a stream established, it is very easy to change the composition, temperature, and pressure by using the Prode functions in Mathcad. For some problems, you may only need one stream with all of the components in the process which can be modified as needed.
The variables can be expressed in their common manner such as the delta symbols used above. I will have more in a later blog on formatting and layout guidelines that I follow to keep the programs uncluttered and organized for easy reading.