Page 227 - APPLIED PROCESS DESIGN FOR CHEMICAL AND PETROCHEMICAL PLANTS, Volume 1, 3rd Edition

Pumping of Liquids 199

le 3-13: System Head Using Two Different Pipe
Sizes in Same Line 50
45
The system of Figure 3-53 consists of the pump taking
suction from an atmlospheric tank and 15 feet of 6-inch
pipe plus valves and fittings; on the discharge there is 20
feet of 4inch pipe in :series with '75 feet of 3-inch pipe plus c -
TI
a control valve, block valves, fittings, etc. The pressure of m I
the discharge vessel I(bubb1e cap distillation tower) is 15
psig. Using water as the liquid at 40°F
Suction: 6-inch pipe (using Cameron Tables-Table 2-
22). TQ simplify cabxlations for greater accuracy, use
detailed procedure of Chapter 2.
0 10 20 30 40 50 60 70 80 90 lo0 110 120 130 140 150 160
System Flow, Opm.
Pipe or Figure 3-52. System head curves for variable static head.
Fittinc Loss 200 GPM 300 GPM
Loss, fr/100 ft 0.584 1.24
For 15 ft 15.0 ft
Two, 90" ell, eq 22.8
Gate valve, open 3.2
Total 41.0 ft 0.24 ft. 0.51 ft
___ ____ .___ ~
- __ _ _ _

The total suction head = h, = +7 - 0.24 = +6.76 at
200 gpm

h, = +7 - 0.51 = f6.49 at 300 GPM
150 Dircreponcy due !a
Variation in Friction
Discharge:

IO0
4 inch pipe 3 inch pipe c
z
a.
200 GPM 300 GPM 200 GPM 300 GPM
.-
c
Loss, ft/lOO ft 4.29 9.09 16.1 34.1 0
a
0)
For 20 ft 20.0 20.0 X 50
For 75 ft 75.0 75.0
Two, 3", 90" ells, eq. 8 8
One, 4", 90" ell, eq. 4.6 4.6
1.7 ft
One Gate Valve open .- -- __ 1.7 ft
Total, equivalent ft 24.6 24.6 84.7 84.7 0
Friction loss, ft fluid 1.06 2.23 13.6 28.8 0 100 200 300
Control valve at 60% Gallons per Minute
20.4
of total, ft fl .- 1.59 ~- 3.34 - 43.2 Figure 3-53. System head using two different pipe sizes in same line.
Total discharge friction
loss, ft ~ 2.65 ~ 5.57 _ 34.0 _ 72.0
_
Total head on pump at 300 GPM =
Total static head = 45 -- 7 + 15(2.31) = 72.6 ft, SpGr = 1.0 H = 45 + 15(2.31) + 5.57 + 72.0 - 7 + 0.51 = 150.68 ft
Composite head curve
at 200 GPM: head = 72.6 + 0.24 + 51.65 + 34.0 = 109.49 ft The head at 200 GPM (or any other) is developed in the
at 300 GPM: head = 72.6 + 0.51 + 5.57 + 72.0 = 150.68 ft same manner.