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  Cooling Towers Cleaning


Organic Water Treatment Chemicals
Steam Boilers, Cooling Towers, Hot And Chilled Closed Systems
Fuel Oil Treatment
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Cleaning a cooling system fouled with calcium carbonate (Lime)

Calcium carbonate, or lime, is one of the most common scales found in industrial cooling systems. It occurs when the solubility of calcium carbonate is exceeded due to excessive calcium or alkalinity levels, insufficient chemical inhibitor, high temperatures, or a combination of any or all of these factors.

The safest method to remove this scale from the system is through the use of an inhibited sulfamic acid based product s. However, in large systems this may not be economical. In such cases the following method may be used. It should be noted that this method does put the system at a higher risk of metal loss due to corrosion. The procedure is as follows:

  1. Calculate the LSI of your system. If you do not know the temperature, you can estimate it by adding 25 F to the highest heat exchanger exit water temperature.
  2. Utilize a pH controller and acid to suppress the pH such that the LSI will be less than 0 but no lower than 1. A slightly negative LSI will tend to dissolve calcium carbonate.
  3. Monitor calcium levels. They should increase over time and plateau when the cleaning is complete. Duration will depend on the severity of the scale. Please note that you may need to increase blowdown to maintain calcium levels below 1000 ppm.
  4. Once calcium levels have reached a plateau, resume your normal conductivity, pH and chemical control program.

Note: During the cleaning process it is suggested that you increase the feed of a calcium carbonate dispersant. For recommendations please contact our technical support staff.

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