Page 120 - APPLIED PROCESS DESIGN FOR CHEMICAL AND PETROCHEMICAL PLANTS, Volume 1, 3rd Edition

104 Applied Process Design for Chemical and Petrochemical Plants

YaluesefCa
-
w c,
2500
191

19111
w w
II ,1 ,1 II 1IIOO m
.OS ,m
' ,DI !IOI IOO
• .117 ,15 IOO a
7111
JS
1 � ,2 111 !!ell
15
.14 ,25 a
Pressure Drop per 100 feet Pipe: i ' .03 .3 I IIO DI
...
ilP100 = C1C2V = Ci Cz • ... .D2S .4 a l 5111 250
p I .112 .s I 2QJ
.,
a.
C1 = � DO = Jl.P100P C2= � 0 =ilP100P - • .1115 a .7 25 0 400 1!11 -s
...
..
..
0
..
C2V C2 C1V C1 0 .I 'O 0
J 3,5 ., JI Ii
:::,
!I
C1 = Discharge Factor from Chart .01 ii LO � 1111 '11
:::,
.,. .
C 2 = Size Factor, from Table 2-11 I- 3 .00, > I- D) 90 >
.!:
.,..
.!:
IQ
,OOI
.a11
�
"'"
For llP>40% P1, do not use this method. - 2.5 .ms LS 40 .9 250 10
ii
For Jl.P between 10% and 40% of P1, use average for V. j .Dll9 0 50
0
�
For Jl.P<10% P1, use Vat P1 or Pz. c,:
ilP100 = Psi, pressure drop per 100' pipe. .OOt 2.5 50 = ZIO 40
v = Specific Volume, cu ft/lb. = ,1I03 3 l)
IO
.1»25 25
Note: For quick estimates; not as accurate as friction LS ISO
loss calculations JI02 70 10
.ocns II 15
a 90
9
LI .001 10 m 100 10
.0009
J .Gall
.GJ07
,I
JI006
Figure 2-31. Simplified flow formula for compressible fluids. By permission, Crane Co., Technical Paper #410, 1957. Also see 1976 edition.
6. Calculate pressure drop, LiP/100 ft ( or use Figure 2-34). ing pipe size. Consider reducing losses through
items in step 5 above. Recheck other pipe sizes as
may be indicated.
0.000336 fW 2
�P/100 feet = (2-77)
pd5
0.000000726 fTSs ( (b ) 2 Example 2-8 Pressure Drop for Vapor System
1
P d 5 (2-77A) The calculations are presented in Figure 2-35, Line
7. Total pressure drop, LiP total Size Specification Sheet.
Figure 2-36 is convenient when using Dowtherm vapor.
= (L + Leq) (�PI 100) + Item 5 (2-57)
8. If total line or system drop is excessive, examine the Alternate Solution to Compressible Flow Problems
portion of drop due to pipe friction and that due to
other factors in the system. If the line drop is a small There are several good approaches to recognizing the
portion of the total, little will be gained by increas- effects of changing conditions on compressible flow [ 44, 47].