MIL-HDBK-1003/7
operating pressure of the boiler. Water treatment of raw water may also be required in
conjunction with cycle water makeup treatment and/or to provide potable water for
domestic use, all depending on the quality of the raw water supply. Where a
demineralizer is used for cycle water makeup, it shall be sized as follows:
EQUATION:
Gallons/day = (0.015 x F x 24 x 60 + SA + SB + P) / 500
(14)
where:
F
=
Maximum boiler steam flow, lb/h
SA
=
Atomizing steam requirements, gal/day
SB
=
Soot blower steam requirements, gal/day
P
=
Process or heating steam and condensate losses, gal/day
The demineralizer should be sized to produce the amount of water as
determined by Equation 14 by operating the demineralizer 18 hours per day, leaving 6
hours per day for demineralizer regeneration. The sizing should also be such that it
should not be necessary to regenerate the demineralizer more than once per day. For
additional information see MIL-HDBK-1003/6.
12.4
Cooling Water Systems
Once-Through System. Once-through systems have an intake structure including
12.4.1
screens, cooling water pumps to provide for water static and dynamic head losses, a
condenser, conduits to carry the water, and a discharge or outfall structure located so
that significant recirculation of warm water will not occur.
12.4.2
Recirculating System
12.4.2.1 Evaporative Wet Cooling.
This system utilizes cooling towers (natural or
mechanical draft) or basins.
12.4.2.2 Non-evaporative Dry Cooling. Cooling water is pumped through a closed circuit
passing through the condenser where heat is absorbed, then through a water-to-air heat
exchanger, and finally back to the cooling water pumps for recycling.
12.4.2.3 Combination Wet and Dry Cooling. This system uses a combination of wet and
dry systems as described above. The cooling tower combines a water to air heat
exchanger section with an evaporative type cooling section. The advantages of the
wet/dry tower as compared to the wet tower are lower water consumption and reduced water
vapor (plume) discharge.
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