Water is required to be cooled for many processes, for example air conditioners, manufacturing processes or power generation, etc. A cooling tower is used to reduce the temperature of a water stream by extracting heat from water and emitting it to the atmosphere. Cooling towers make use of evaporation whereby some of the water is evaporated into a moving air stream and subsequently discharged into the atmosphere. As a result, the remainder of the water is cooled down significantly. Water by its basic nature is corrosive. Therefore cooling systems are plagued with corrosion.
Many factors affect corrosion rates in a given cooling water system. The presence of dissolved gases, chloride and sulphate levels, pH, alkalinity, scaling tendency, and protective ions such as calcium, magnesium, phosphate nitrate, and silicate must all be taken into consideration. The first step to control is detection therefore regular monitoring of the above is absolutely essential.
|Parameter||Range||No of Test|
|Total Hardness||2-40, 5-100, 25-500 mg/l as CaCO3||
|Calcium Hardness||5-100 mg/l as CaCO3|
|Alkalinity||10- 200 & 100-2000 mg/l as CaCO3|
|Chloride||10-200 & 50-1000 mg/l as Chloride|
|pH||4 to 10|
|Iron (Low Level)||0.05, 0.1, 0.3, 0.4, 0.7, 1.0, 1.5, 2.0 mg/l as Fe|
|Silica||5, 10, 20, 40, 60, 80 mg/l as SiO2|
|Orthophosphate||0, 5, 10, 20, 30, 40 mg/l as PO4|
|Free Chlorine||0.1-2.0 mg/l as Chlorine|