Page 115 - Petroleum and Gas Field Processing

Figure 24 Determination of the A factor.

A is a dimensionless constant evaluated from Figure 24 using M and a
parameter, Z (the sum of the mole fractions of the hydrocarbons
C 1 þ C 2 þ C 3 ) found in the feed.

Approximate Formula
The following simplified formula can be used for determining (P 2 ) o as a
function of P 1 and P 3 [8]:
0:5
ðP 2 Þ ¼ðP 1 P 3 Þ ð28Þ
o
Example 3.5
A well fluid with the composition (in mole fraction) C 1 ¼ 0.4, C 2 ¼ 0.2,
C 3 ¼ 0.1, C 4 ¼ 0.1, C 5 ¼ 0.1, C 6 ¼ 0.05, and C 7 ¼ 0.05 is to undergo a gas–oil
separation process using a three-stage GOSP. The last stage is operated at
atmospheric pressure. The first stage is fixed at a pressure of 500 psia.
Calculate the optimum operating pressure for the second stage using
(i) Equation (27a) or (27b)
(ii) Equation (28)

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