Cooking water treatment plays a vital role in the industry

1. Cooling water treatment

2. Introduction
• Cooling water plays a major role in the process industry.
• So maintain the cooling water at the correct specification will
not causes the process equipment.

3. Treatment for
• Corrosion
• Fouling
• Scaling
Corrosion
• Destruction of metal by chemical or electrochemical reaction.
• Corrosion was measured in the terms of MPY (Mills Per Year)

4. Corrosion control methods
• Corrosion was controlled by using the PO4 and Zn.
• PO4 was dosed in the initial time of the startup to form the
passivation layer in the metal surface
• The PO4 was maintained by dosing the SCI-3164
• PO4 was maintained at 8-10 PPM
• Zn was dosed regularly in the cooling water.
• The Zn will react with the

5. Scaling
• Deposition of salt in the surface of the equipment which may
damage the equipment and reduces the heat transfer rate
• Dissolved particles in the water causes scaling such as
carbonates, Bicarbonates, Hydroxides.

6. Scaling control measures
• These are to be removed from the system by dosing the
stressperz, MBR 20 , BD 20 are the biological dispersant, SIL-4300
(Anti scalant) and SIL-5000(Silica disperser).

7. Microbiological fouling
• Total viable count
• Sulphate reducing bacteria
• Nitrifying bacteria
To control these factors Biocides are added into the cooling water
The biocides are classified into two category
• Oxidizing biocide
• Non-oxidizing biocide

8. Oxidizing biocides are used the kill the anerobic bacteria.
Non-Oxidizing biocides are used to kill the aerobic bacteria
• Chlorine
• Chlorine dioxide
• SBQ (NaBr)
Oxidizing biocide
Non-oxidizing biocides
• SB1,2,3
• TA101
• DBN-20

9. VAG
• VAG are used to reduce the turbidity in cooling water.
• It removes the dissolved solids by using the sand filter as an
filter medium.

10. Parameters to be maintained in cooling water
pH - 7.2-7.8
Turbidity - max 50
Conductivity - max 3000 ppm as CaCO3
M-Alkalinity - max 300 ppm as CaCO3
Total Hardness - max 500 ppm as CaCO3
Cal.Hardness - max 350 ppm as CaCO3
Chlorine - max 700 ppm as CaCO3
Sulphate - max 1000 ppm as CaCO3
Silica - max 70 ppm as CaCO3
Total iron - max 2 ppm as CaCO3
Zinc - 1.5-2.5 ppm
PO4 - 8-10 ppm
Dispersant - 50-70 ppm
FRC - 0.2-0.5 ppm
COC - 4 - 6
RSI - 6.2-7.0
LSI - -0.3 – 0.5