OZONE Ozone in cooling towers
Ozone in cooling towers
Ozone is a strong disinfectant and an interesting alternative for the chemical biocides in cooling tower water treatment. The use of ozone in cooling towers has some great advantages. Ozone also has its limitations, which when kept in mind during the design phase, should not cause problems:
The advantages of ozone are:
· Safe and easy in use
· Low maintanance costs
· Ozone is produced on-site and requires no storage of dangerous chemicals
· Ozone requires no additional disinfectants
· No cocktail of disinfectants necessary. Micro-organism can not get resistant to ozone after prolonged use of ozone
· High efficiency as disinfectant. A residual ozone concentration of 0.1 to 0.2 ppm is in most cases very effective in keeping the cooling tower and the cooling circuit clean.
· Very effective in removing biofilms
· Higher efficiency of heat exchangers due to reduced biofilm formation
· No chlorinated compounds. Very low corrosion rates in the system.
· No persistent chemicals or disinfectants in bleed. Ozone breaks down to oxygen.
· In some cases ozone can replace disinfectants and also dispergents and inhibitors
· In many cases a higher concentration factor is possible
· Lower operational costs and in many cases a lower overall costs
· Ozone is effective in a wide pH range
· Also effective for mussel growth
In the design of a proper ozone disinfected cooling tower, one needs to take care of the following points
· Suppletion water with high hardness and / or high COD levels is less suitable for ozone based cooling towers
· Retention time in the system. The half time of ozone is normally less than 10 minutes in cooling systems. Toassure an adequate residual ozone concentration it is necessary to start with an adequate begin concentration.
· Dead spots. Because ozone depletes to oxygen, spots with little circulation have to be prevented.
· Temperature. The solubility of ozone and the half life time of ozone decreases at higher temperatures. This limits the temperature of the cooling water in which ozone can be used. This limit is in most cases around the 45°C.
· Material. The meterials used in the cooling tower need to be ozone resistent.
If there are any questions, please contact us.