Corrosion Of Cooling Water System Due To Chlorination
Corrosion Of Cooling Water System Due To Chlorination
(OP)
I am responsible for several cooling tower water systems. Our standard procedures, etc require us to chlorinate the systems every six months. We used to get the measured Free Chlorine to 25 mg/l (equivalent to 25 ppm) and circulate for two hours. Recently, some of our colleagues have instead been maintaining 50 mg/l for 1 hour. The disinfection is more or less the same (twice as much free Chlorine, for half the time), but which is preferable with regard to minimising system corrosion? The systems typically contain stainless steel cooling towers, steel pipework and copper heat exchangers. Note; in both cases, we first add inhibited Hydrochloric Acid to bring the pH down to about 6.5, then add the Sodium Hypochlorite solution.
Thanks,
Brian
Thanks,
Brian





RE: Corrosion Of Cooling Water System Due To Chlorination
What really counts for the SS (depending on which ones you have) is the residual *chloride* content of the water, and the avoidance of stagnant/low flow areas.
RE: Corrosion Of Cooling Water System Due To Chlorination
RE: Corrosion Of Cooling Water System Due To Chlorination
Metalguy: Don't worry, the six-monthly disinfection is not the only way we have of controlling microbiological activity! We run with about 3-4 mg/l free Bromine all year, plus some "quat" biocide. The six-monthly events are in addition to our daily routines. The system is an open evaporative cooling tower system.
Regards,
Brian