Page 140 - APPLIED PROCESS DESIGN FOR CHEMICAL AND PETROCHEMICAL PLANTS, Volume 1, 3rd Edition

126 Applied Process Design for Chemical and Petrochemical Plants

3. Calculate value times 1.1 to 2.0, depending upon critical
nature of application.
X = (APL/AP,)l/2 (2-114)
APTph = APTP L + n h F,pL/144 (2-118)
4. Calculate 8 for types of flow selected from Figure
2-40 [33].
where pL is the density, lb/cu ft, of the liquid flowing
in the line, and F,, elevation factor using gas veloci-
Type flow Equation for QGIIT ty, v.
Froth or Bubble @ = 14.2 X0.75/Wm0.1
Plug @ = 27.315 X0.s55/W rn 0.17 F, = 0.00967 Wrn0,5/v0,7, for v > 10 (2-119)
Stratified @ = 15,400 X/Wmo.’
Slug Q = 1,190 X0.185/WmO.5
Annular” @ = (4.8 - 0.3125d) X0.348 - 0.021d or as an alternate: F, = 1.7156 Vg-0.’02 (2-1 20)
*Set d = 10 for any pipe larger than 10-in.
X = [APL~~./AP~~~I~’* Use Figure 2-42 for v less than 10. Most gas trans-
mission lines flow at from 1-15 ft/sec.
5. Calculate two-phase pressure drop, horizontal por- For fog or spray type flow, Baker [33] suggests using
tions of lines. For all types of flow, except wave and Martinelli’s correlation and multiplying results by two [46].
fog or spray:
(a) For gas pipe line flow, the values of QGTT may be
AP~~ APG@GTT, psi per foot (2-1 15) converted to “efficiency E” values and used to cal-
=
culate the flow for the horizontal portion using a
For wave [52]. fixed allowable pressure drop in the general flow
equation [33]. The effect of the vertical compo-
APTP = fTp (G’,)‘/193.2 dPg, pSi/fOOt (2-1 1 6) nent must be added to establish the total pressure
drop for the pumping system.
where
-I
fTp = 0.0043 (Wm~L/Gpg)0.214 (2-117) 38.7’744Ts (PI2 - P,‘ )d5
d 14.66 - lOOOP, L,S,TZ
6. Total two-phase pressure drop, including horizon-
tal and vertical sections of line. Use calculated where 14.65 refers to reference pressure P,.

Liquid Head
Factor, F,
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.
I

Superficial Gas Velocity, ft./sac.
Figure 2-42. Estimating pressure drop in uphill sections of pipeline for two-phase flow. By permission, 0. Flanigan, Oil and Gas Journal, Mar.
10, 1958, p. 132.