UFC 3-240-13FN
25 May 2005
process is illustrated in Figure 2-4. During operation of the demineralizer, it is necessary
to check the outlet water at regular intervals. The TDS of the outlet water should always
be less than 1 ppm. The ion exchange resin must be regenerated if the TDS exceeds 1
ppm. This check can be performed daily, once per shift, or as required depending on
unit capacity.
Figure 2-4. Demineralization Process
Carbon
Dioxide
Raw Water
and Air
Cation
Anion
Exchanger
Exchanger
Air
Decarbonator
Treated
Water
2-2.5.3.1
described in paragraph 2-2.5.2. The anion exchange process involves reactions of
hydroxyl-regenerated zeolite with the effluent from the hydrogen ion exchanger:
→
Hydrogen and
+
Hydroxyl Zeolite
Water
+
Sulfate/
Anions
Chloride
Zeolite
2-2.5.3.2
Anion Ion Exchange Regeneration Method. The spent anion ion
exchange material containing chlorides, sulfates, and other anions is regenerated with
sodium hydroxide (caustic).
→
+
Sodium Hydroxide
Hydroxyl
+
Sodium and
Sulfate
Zeolite
Anions
Chloride
Zeolite
24
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