1. Calculation of Thermodynamic Properties of Real Fluids Using Peng-Robinson EoS Program Provided by Professor S.I. Sandler

2. Installation of Visual Basic Program
Access the CD drive and click "OPEN".
This should open a listing of the folders on the CD, named for the assets they contain.
Select the folder "VISUAL BASIC PROGRAMS"

3. Select the folder "Property package"

4. Select the icon "setup.exe" and follow the installation instruction.
This program will allow you to access properties of pure components

5. Go back to the folder "Peng Robinson Package"

6. Select the icon "setup.exe" and follow the installation instruction.
This program will allow you to calculate thermodynamic properties and VLE of pure fluid using the Peng-Robinson equation of states

7. Other Programs You can install other programs in a similar manner
Peng-Robinson for mixtures
Modified UNIFAC
Chemical Equilibirum
A folder "sandler" will appear on the "startup" menu

8. Ex. 6.65
Pipelines are used to transport natural gas over thousands of miles with compressors (pumping stations) at regular intervals along the pipeline to compensate for the pressure drop due to flow.
Because of the long distance and good heat transfer, the gas remains at ambient temperature of 20oC
At the pumping station the gas is compressed with a single stage compressor to 4 MPa and then isobarically cooled back to 20 oC
Because of safety and equipment constraints, the gas temperature during compression should not exceed 120 oC
Assuming that the natural gas is methane that is described by the Peng-Robinson equation of state, how low pressure is allowed before the as should be recompressed

9. Solution Find entropy of methane at 4 MPa and 120oC
4 MPa, 120 oC
Methane
4 MPa, 20 oC
Cooler
Methane
?? MPa, 20 oC
Compressor
adiabatic
reversible
Find entropy of methane at 4 MPa and 120oC
Assume the compression is isenthropic
Find the pressure of methane at 20 oC that have the same entropy as methane at at 4 MPa and 120oC

10. Activate the "startup" menu and run the "sandler"--"Peng Robinson equation of state"

11. The following window will popup

12. Click on "Find Component"
Type "methane"
Accept

13. The critical properties of methane will appear

14. Calculate properties of methane at 120 oC and 4 MPa using filling in the conditions and pressing the button "Calculate EOS"
Entropy of methane at 120 oC and 4 MPa is found to be -21 J/(kmol K)

15. Calculate the entropy of methane at 20 oC and different pressure
The entropy of methane at 20 oC was found to be -21 J/(kmol K) at ~11 MPa