Page 68 - PVT Property Correlations

46 PVT Property Correlations

TABLE 3.12 Gas-Specific Gravity
Y i (mol%) M W (Mo.Wt.) y i 3 M W
Hydrogen sulfide 0.50% 34.08 0.17
Carbon dioxide 1.25% 44.01 0.55
Nitrogen 0.00% 28.01 0.00
Methane 75.75% 16.04 12.15
Ethane 8.25% 30.07 2.48
Propane 6.35% 44.10 2.80
i-Butane 2.15% 58.12 1.25
n-Butane 2.25% 58.12 1.31
i-Pentane 1.15% 72.15 0.83
n-Pentane 1.10% 72.15 0.79
Hexanes 0.50% 86.18 0.43
Heptanes plus 0.75% 143.00 1.07
Sum 1 23.84
Gas Sp. Gr. 5 23.84/29.1 5 0.82.

and

y HC 5 1 2 y N 2 2 y CO 2 2 y H 2 S ð3:24Þ
Then:
y HC 5 1 2 0:0 2 0:0125 2 0:005 5 0:9825
0:82 0:17 1 0:55 1 0:0Þ=29:1
ð
γ 5 5 0:021
gHC
0:9825
2
P PcHC 5 744 2 125:4 3 0:021 1 5:9 3 0:021 5 741:4
2
T PcHC 5 164:3 1 357:7 3 0:021 2 67:7 3 0:021 5 171:7Fð631:4RÞ

Using Gas Composition to Calculate the Gas Mixture Critical
Properties
First, we need to calculate the critical properties for C7 1 .We use Riazi and
Daubert (1987).
T c 5 544:4 3 Mo:Wt: 0:2998 3 γ 1:0555 3 e 21:3478 3 10 24 3 Mo:Wt:20:61641 3 γ ð3:25Þ