UFC 3-240-13FN
25 May 2005
COC = Bmhos / Fmhos
EQUATION
or
(5)
5000 mhos / 250 mhos = 20 COC
b) The percent blowdown is:
%B = 100/COC
EQUATION
or
(6)
100/20 = 5%
c) If the boiler is producing 5 kilograms per second of steam (40,000 pounds
per hour), the blowdown must be:
EQUATION
B = E (COC - 1)
(7)
= 5.0 (20 - 1) = 0.26 kg/s (2105 lb/hr)
d) The feedwater is calculated to be:
EQUATION
F = E + B = 5.0 + 0.26 = 5.26 kg/s (42,105 lb/hr)
(8)
This is equivalent to 5.3 liters per second (5054 gallons per hour at 8.33
pounds per gallon). This example is illustrated in Figure 3-9.
Figure 3-9. Simplified Boiler System Water Balance
Condensate Return (R)
Steam Lost (L)
3.8 kg/s
1.2 kg/s
(30,316 lb/hr)
(9684 lb/hr)
Pegging Steam
Steam Generated (E)
5 kg/s
Feedwater (F)
(40,000 lb/hr)
5.26 kg/s
Makeup (M)
(42,105 lb/hr)
Steam Boiler
1.5 kg/s
(11,789 lb/hr)
Blowdown (B)
0.26 kg/s
(2105 lb/hr)
3-1.6
Determining Makeup Water and Condensate Return Rates. Makeup is
the water from the external water treatment system added to the boiler system
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