Page 141 - Petroleum and Gas Field Processing

0.5

0.45
0.4
0.35
0.3

0.25
0.2
0.15

0.1
0.05
0
0 0.1 0.2 0.3 0.4 0.5

Figure 6 H o =D as a function of A w =A.

Gas Capacity Constraint
The gas capacity constraint equation developed for two-phase horizontal
separator in Chapter 3 is also valid for three-phase horizontal separators.
The equation provides a relationship between the separator diameter and
effective length as follows:

Q g TZ g C d
1=2
LD ¼ 422 ð13Þ
P
o g d m
where D is the separator internal diameter (in.), L is the effective length of

the separator (ft), T is the operating temperature ( R), Z is the gas
compressibility at operating pressure and temperature, P is the operating
3
pressure, g and o are the gas and oil densities, respectively (lb/ft ), C d is
the drag coefficient, and d m is the minimum oil droplet size to be separated
from gas (mm). As discussed in Chapter 3, d m is normally taken as 100 mm
and C d is determined by the iterative procedure described there.
Using diameters smaller than the maximum diameter determined
from the above water droplet settling constraint, Eq. (13) is used to
determine possible diameter and length combinations that satisfy the gas
capacity constraint.

Copyright 2003 by Marcel Dekker, Inc. All Rights Reserved.