文档介绍：ASHRAE Journal
Water Treatment
In Closed Systems
By Darrell Hartwick
losed systems monly classed by their function — either lowing mechanism.
3 N H + 6 OH–→ 2 NH + 2 N
heating (hot water) or cooling (chilled water). They typically rely 2 4 3 2
+ 6 H O (2)
on water or water-based solutions as their heat transfer fluid. 2
NH + Cu+2 → Cu (NH )+2 (3)
C 3 3
While various ways exist to classify water treatment product technolo-
Both hot and cold loops have all the
gies, one of the simplest is whether the primary corrosion inhibitors are conditions for these reactions to take
reducing agents, oxidizing agents, or film formers. place, including the oxygen needed to
oxidize the copper metal and ammonia that
dissolves copper oxide. The dissolved
In addition to the primary corrosion in- ally recognized that the reaction proceeds
copper is free to plate on to steel sur-
hibitors, factors such as fluid pH and cop- via a free radical mechanism. The overall
faces in the system where it can cause
per ions also affect corrosion. Supple- equation is:
galvanic corrosion. When the copper
mental agents are used to buffer/control
½ O + Na SO → Na SO (1) plates out, it releases the ammonia, which
pH and minimize yellow metal corrosion. 2 2 3 2 4
is free again to repeat the cycle. As a re-
The primary corrosion inhibitors, which With this technology