The step-by-step process for the chemical treatment startup of a new cooling tower, including flushing, bio-cleaning, low pH cleaning, passivation, and regular treatment initiation.
COOLING WATER TREATMENT STARTUP PROCEDURE
1. Initial Preparation
a) Inspection of System:
- Check the cooling tower, pipelines, heat exchangers, and basin for any debris, rust, or construction residue.
- Ensure valves, pumps, and dosing systems are properly installed and functional.
b) Water Source Analysis:
- Test the makeup water for pH, TDS, hardness, alkalinity, and microbiological contamination.
c) System Flushing:
Remove any loose debris and contamination:
- Fill the cooling system with clean water.
- Operate pumps and circulate water for 2–4 hours.
- Blowdown till turbidity & TSS initial level.
2. Bio-Cleaning Process
a) Oxidizing Biocide Dosing:
- Add an oxidizing biocide (e.g.Naocl) to disinfect the system and add Bio dispersant to clean the system.
- Maintain free residual chlorine at 0.6 – 1.0 ppm for 8–10 hours.
- Monitor the Cooling water parameter of pH, Conductivity, TDS, Turbidity.
- Start Blow-Down to reduce the Turbidity initial level
b) Non-Oxidizing Biocide Dosing:
- Dose Non-Oxidizing Biocide in the cooling tower for removal of Biological Growth from the System.
- Circulate the water for 18 Hrs.
- Monitor the Cooling water parameters of pH, Conductivity, TDS, Turbidity,
- Start Blow-Down to reduce the Turbidity initial level.
3. Low pH Cleaning
- Ensure all Blow-Down Valves should be closed.
- Start to reduce circulating cooling water pH around 5.5-6.5 by dosing of H2SO4.
- Monitor and maintain pH during the process by adding acid as needed.
- Check the Cooling water parameter of pH, Conductivity,Turbidity, Calcium Hardness & Iron contain for every 4 Hrs. in CW.
- After 8 -10 Hrs. takes Blow-Down from system till all parameter comes down to nofrmal range.
4. Passivation (Corrosion Protection)
- Add the passivation chemical.
- Maintain proper pH (7.2–7.6) and inhibitor concentration as recommended by the chemical supplier.
- Check pH, Conductivity, iron, O-po4, Turbidity for every 4 Hrs. in CW.
- Circulate the solution for 24–48 hours to form a protective layer on the metal surfaces.
5. Regular Treatment Startup
Regular chemicals dosing started from next day as per recommended dosing to maintain the parameter through metering pumps.
- Corrosion Inhibitors: To protect metal surfaces.
- Scale Inhibitors: To prevent scaling.
- Oxidizing Biocides: For microbial control.
- Dispersants: To prevent fouling and improve cleanliness.
Baseline Testing:
- Test water for pH, conductivity, hardness, alkalinity, Turbidity & others recommended parameters.
- Ensure water chemistry is within the recommended ranges.
6. Continuous Monitoring and Maintenance
a) Dosing Automation:
Set up chemical dosing pumps for continuous or periodic dosing as per system requirements.
b) Regular Blowdown:
Adjust blowdown rates to control cycles of concentration and maintain water quality.
c) Routine Testing:
- Conduct daily/weekly water tests for pH, TDS, microbial activity, and chemical levels.
- Adjust chemical dosing as necessary.
d) Recordkeeping:
Maintain logs of water test results, chemical consumption, and operational parameters for performance tracking.
7. Safety Precautions
PPE Usage:
Ensure operators wear appropriate PPE (gloves, goggles, masks) while handling chemicals.
Chemical Handling:
- Follow proper handling and storage procedures for each chemical.
- Keep MSDS (Material Safety Data Sheets) readily available.
