HW 6 PGE 427 Spring 2020 - Solution (1).pdf - PGE 427...

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PGE 427 - Properties of Petroleum Fluids - Spring 2020
Problem Set 6
Assignment Date: March 9, 2020 Due Date: March 27 April 3 , 2020 by 1:00 PM
1. (25 points) Make a Px diagram for the C
2
/nC
5
binary at 300 K using PVTsim with the PR EOS.
a. (6 points) Draw at least 3 tie lines within the two-phase region.
b. (4 points) Indicate saturation (vapor) pressures for 100% C
2
and 100% nC
5
on the
diagram.
c. (4 points) Also indicate the dew-point curve and bubble-point curve.
d. (5 points) Is there any critical point in this diagram? Why, or why not?
e. (6 points) What will be the bubble point and the dew point for a mixture of 80 mol% C
2
and 20 mol% nC
5
at 300 K, on the basis of the diagram created? For this last question,
perform a saturation pressure calculation with PVTsim.
No critical point is present in this diagram because the temperature, 300 K, is lower than the
critical temperatures of the two components (422.05 K and 462.71 K).
0
1000
2000
3000
4000
5000
0 20 40 60 80 100
Pressure, kPa
C
2
mole percent
Bubble-point curve
Dew-point curve
Vapor pressure of nC5
Vapor pressure of C2

2
2. (40 points) [PVTsim] This is a question regarding phase envelope and equilibrium concept.
a. (10 points) Using PVTsim with the PR EOS, show the following on the same P-T figure:
- PT cross section for the equimolar mixture of C
2
and nC
5
- Vapor pressure curve of C
2
- Vapor pressure curve of nC
5
.
Indicate the critical point of the equimolar mixture clearly.
b.