Tips & Tricks: Use the Property Table to Visualize the Phase Map
One very powerful feature of the Property Table unit operation is the ability of showing a “Phases plot”. The density plot option in the plot tab can be used to visualize the phase map of a fluid. Having a visual aid to determine the position of the current operation point with respect to the different phase regions for the fluid of interest is an invaluable piece of information for the proper design and analysis of the process.
The following example will show how to set up a Property Table unit operation to generate the phases plot. The envelope.vmp case from the manual example folder will be used.
Initially, when you open the case you should see the following process:
Add a material stream and connect it to the out port of the Env3 Envelope unit operation. Then add a Property Table unit operation and connect it to the material stream, your case should look like this:
Open the PT1 Property Table unit operation form and go to the Variables tab.
Now select Temperature as the X-Variable and specify -400 F for the Minimum value, 100 F for the Maximum and 100 for the Number of Points. Similarly, select Pressure as the Y-Variable and specify 0.1 psia for the Minimum value, 1000 psia for the Maximum and 100 for the Number of Points.
For the Dependent Variable select BULK as the phase, and add VF (vapour fraction) as the only variable. The fully specified Property Table unit operation should look like this:
After is finished solving, go to the Plot tab, select the Z-Prop Density Plot radio button and from the Z prop drop down select PHASES. The PT phase map for the fluid, in the specified range, will be shown:
The Show Port radio button allows you to see the current conditions of the stream connected to the Property Table. Select Yes in the Show Port radio button and change the conditions of the S1 material stream to T = 0 F and P = 500 psia.
You can now see the current conditions for the fluid and visually determine that it is in the vapour region.
Please contact your local VMG office for more information.