Page 137 - 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 [38]:
Lm = pipe length, miles

or frcm Reference [3]: Bend Radius Add", as pipe diameters, de
1 Pipe dia. 17.5
1.5 Pipe dia, 10.4
2 Pipe dia. 9.0
Example 2-12: Use of 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, 2-18, 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 ·weymouth '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 iongest length of
ture of 60°F, 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 of80°F, and specific gravity of0.74. (2-103)

Multipliers from the tables are:
Pressure base: 0.9796 where Lm is the length of pipe of size d to be used.
Le is the equivalent length of pipe size cl, length Lm
Temperature base: 1.0192 after conversion to basis of reference diameter, d.,
Specific gravity base: 0.9005
Flowing temperature base: 0.9813
New base flow The calculations can be based on diameter de and a
= (5,600,000) (0.9796) ( 1.0192) (0.9005) (0.9813) length of all the various Le values in the line plus the
length of line of size de, giving a total equivalent length
= 4,940,000 cu ft/day for the line system.
Panhandle-A Gas Flow Formula [3]
Modified Panhandle Flow Formula [15]
This formula is considered to be slightly better than
0
the ±10 percent accuracy of the Weymouth formula. %s = 737.2 E (T /P 0) 102 [[P/ (1 + 0.67 ZP1)
- P22 (1 + 0.67 ZP2)J/T Lm G0.961]051 (d)253 (2-104)

)1.01ss1[ lo.;394 where Lm = miles length
= P/- P/
q 435.87E(T ip d = inside diameter, in.
d, S I S s 0.8539TI z T = flowing temperature, R
g "rn
d 2.6182 (2- 101) Z = gas deviation, compressibility factor
T = base temperature, (520 R)
O
or E = 0.92, usually 0.8539 G = gas specific gravity
Z = compressibility correction term
13539 P = pressure, psi, absolute
[
S 0.4606
2 435.8_7_(T_,- . 1""" g r_ , _ ) P 0 = base pressure, (14.73 psi, absolute)
P/ - p 2 = l- . O- i 8_8_-<l-2- . 6- 1 8_ 2 _ l TLm q l.B 539 E = "efficiency factor," which is really an adjustment
l
Lo fit the data
f = fanning friction factor
(2 - 102)
qos = flow rate, SCF I day
0
where T = gas flowing temperature, R = 460°F + t
E = efficiency factor for flow, use 1.00 for new pipe
without bends, elbows, valves and change of pipe American Gas Association (AGA) Dry Gas Method
diameter or elevation
0.95 for very good operating conditions See Reference [16] A.GA, Dry 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.