Chemical analysis of tower water

The most appropriate treatment system for the water in a cooling tower has to be selected in order to limit the maintenance of the evaporative tower at minimum and reduce the purge water consumption. First of all it is then suitable to make a chemical analysis of the water employed within the tower. In case the water has values among these following parameters, a simple anti-scaling and biocide treatment will be sufficient.

  • Hardness: 10 ÷ 35° F
  • Alkalinity: 100 ÷ 350 ppm
  • Chloride: 10 ÷ 500 ppm
  • Iron: <0,3 ppm
  • Conductivity: <1.000 microSiemens
  • PH: 6,8 ÷ 8

In case of a hardness value higher than 35° F, water must be softened, or otherwise a conditioner can be employed making attention to the purge cycles and their impact on its concentration. For chloride values over threshold limits, 600-700 ppm, we are probably in the presence of brackish waters, increasing the risk of corrosion: strong corrosion inhibitors are then required, or a careful selection of construction materials.
A high level of salts also increases the conductivity rate. In this case it is necessary to identify which one of the salts is mostly causing the increase of the conductivity value, in order to select the most proper treatment. Iron levels much over 0,3 ppm could require an iron removal system, while a higher PH value probably reveals polluted waters: especially in case of zinc-coated machinery, be careful that the PH value doesn’t surpass 9 ÷ 9,2.

Tempco analisi chimica acqua