Page 289 - Pipeline Rules of Thumb Handbook

276 Pipeline Rules of Thumb Handbook

Solution. 1 05 129 1hp + 139 7hp) = 282hp
. (
.
.
P s = 53 41 psia 1 075 ¥ 282hp = 303hp
.
.
.
P d = 613 41 psia
Nearest nominal size compressor is 300hp.
2 3
.
.
R t = P P s = 11 5 = (3 4 ) = (2 26. )
d
Try solution using 3.44 ratio and 2 stages. Centrifugal compressors
1st stage: 53.41psia ¥ 3.44 = 183.5psia discharge The centrifugal compressors are inherently high volume
2nd stage: 178.5psia ¥ 3.44 = 614psia discharge machines. They have extensive application in gas transmission
systems. Their use in producing operations is very limited.
Horsepower from curve, Figure 3 = 77hp for 3.44 ratio
1 600 000
77hp ¥ , , References
= 123 1 ( for 60 ∞F suction temp. )
.
,
,
1 000 000
1. Engineering Data Book, Natural Gasoline Supply Men’s
460 85∞
+
1st stage: 123.1hp ¥ = 129 1hp Association, 1957.
.
+
460 60∞
2. Dr. George Granger Brown: “A Series of Enthalpy-entropy
+
460 130∞ Charts for Natural Gas,” Petroleum Development and
2nd stage: 123.1hp ¥ = 139 7hp
.
+
460 60∞ Technology, Petroleum Division AIME, 1945.
Generalized compressibility factor
The nomogram (Figure 1) is based on a generalized com-
1
pressibility chart. It is based on data for 26 gases, excluding
helium, hydrogen, water, and ammonia. The accuracy is about
one percent for gases other than those mentioned.
To use the nomogram, the values of the reduced tempera-
ture (T/T c ) and reduced pressure (P/P c ) must be calculated
first.
where T = temperature in consistent units
T c = critical temperature in consistent units
P = pressure in consistent units
P c = critical pressure in consistent units

Example. P r = 0.078, T r = 0.84, what is the compressibility
factor, z? Connect P r with T r and read z = 0.948.

Source

Davis, D. S., Petroleum Refiner, 37, No. 11, (1961).

Reference
Figure 1. Generalized compressibility factor. (Reproduced by
1. Nelson, L. C., and Obert, E. F., Chem. Engr., 203 permission Petroleum Refiner, Vol. 37, No. 11, copyright 1961,
(1954). Gulf Publishing Co., Houston.)