Page 135 - APPLIED PROCESS DESIGN FOR CHEMICAL AND PETROCHEMICAL PLANTS, Volume 1, 3rd Edition

Fluid Flow 121

Z = compressibility factor For bends in pipe add to length [%I:
Lm = pipe length, miles

or from Reference [3] : Bend Radius Add*, as pipe diameters, d,
1 Pipe dia. 17.5
1.5 Pipe dia. 10.4
2 Pipe dia. 9.0
le 2-12: Use o:f Base Correction Multipliers 3 Pipe dia. 8.2
*These must be converted to the unit of length used in the formula.
Tables 2-16, 2-17, ‘2!-1B3 and 2-19 are set up with base ref-
erence conditions. In order to correct or change any base
condition, the appropriate multiplier (s) must be used. If a line is made up of several different sizes, these may
A flow of 5.6 million cu ft/day has been calculated be resolved to one, and then the equation solved once for
using Weyouth’s formula [57], with these conditions: this total equivalent length. If these are handled on a per
measuring base of 60°F and 14.4 psia; flowing tempera- size basis, and totaled on the basis of the longest length of
ture of GOT, and specific gravity of 0.60. Suppose for com- one size of line, then the equivalent length, Le, for any
parison purposes the base Conditions must be changed to: size d, referenced to a basic diameter, de.
measuring base of 70°F and 14.7 psia; flowing tempera-
ture of 80‘F, and specific gravity of 0.74. Le = E, (d,/d)4.s54 (2-103)

Multipliers frolm tlhe tables are:
Pressure base: 0.9796 where E, is the length of pipe of size d to be used.
Le is the equivalent length of pipe size d, length L,
Temperature base: 1.0192 after conversion to basis of reference diameter, de.
Specific gravity base: 0.9005
Flowing temperature base: 0.9813
The calculations can be based on diameter de and a
New base flow length of all the various Le values in the line plus the
= (5,680,000) (0.9796) (1.0192) (0.9005) (0.9813) length of line of size de, giving a total equivalent length
= 4,940,000 cu ft/day
for the line system.

Modified Panhandle Flow Formula [as]
This formula is considered to he slightly better than
the k10 percent accuracy of the Weymouth formula. qos = 737.2 E (To/P,)’.o‘ [{Pi2 (1 + 0.67 ZP1)
- P22 (1 + 0.67 ZP,)]/T L m G0-961]0.51 (d)‘.j3 (2-104)

where L, = miles length
d= inside diameter, in.
T= flowing temperature, R

d 2.6162 (2 - 101) Z= gas deviation, compressibility factor
To = base temperature, (520
G= gas specific gravity
Z= compressibility correction term
P= pressure, psi, absolute
Po = base pressure, (14.73 psi, absolute)
E= “efficiency factor,” which is redly an adjustment
to fit the data
f= fanning friction factor
(2 - 102)
90s = flow rate, SCF/day
where T = gas flowing temperature, “R = 460°F + t
E = efficiency factor for Row, use 1.00 for new pipe
without bends, elbows, valves and change of pipe American Gas Association (AGA)
diameter or elevation
0.95 for very good operating conditions See Reference [ 161 AGA, ry Gas Manual. Some tests
0.92 for average operating conditions indicate that this method is one of the most reliable above
0.85 for poor operating conditions a fixed Reynolds number.