TP08-05: The Application of Solid Water Treatment Chemistry for Cooling Towers

Water has become a precious commodity. Its per capita use in industrialized countries
has increased dramatically over the past twenty-five years. Its cost has increased
dramatically as well.

Years ago, when equipment needed to be cooled, water was pumped out of a nearby
water source (such as a river, well or lake), went into a heat exchanger and was either put
back into that water source or allowed to run off into a nearby stream. This is called
“once-thru cooling”. As water became more expensive and discharge laws more rigid, it
was decided that this water could be reused by means of a cooling tower.

Essentially, this water is being concentrated and reused. When this occurs, mineral
deposits increase and scaling occurs, which impedes heat transfer. The chemistry of the
water must be changed with additives: corrosion inhibitors are used to extend equipment
life, and scale inhibitors are used to prevent mineral build-up (scaling).