Industrial cooling water treatment is a big chapter to learn completely. I worked in this field for more than 10 years & practically observed some problems facing ongoing treatment programmes. I have summarised all these problems, the possible sources of the problem & corrective action plan. If you are working in this field, this guide is very helpful.
Cooling water Treatment Troubleshooting and Action Plans
Problem-1: Test results indicate the Cooling Water system is not within the control range
| POSSIBLE SOURCE | CORRECTIVE ACTION | |
| a. | Test results may be incorrect – system may be within specifications. | Repeat tests to verify results prior to taking any other action. |
| b. | Lab pH meter is out of calibration. | Calibrate meter. |
| c. | pH meter will not hold calibration. | Ref: Instrument troubleshooting guide. |
| d. | pH probe is not functioning. | Replace pH probe & check warranty for return to the manufacturer. |
Problem-2: Cooling water System pH is below
Specification
| POSSIBLE SOURCE | CORRECTIVE ACTION | |
| a. | Acid feed system malfunction or Make up water pH low. | Repair acid feed system: Analyze the water for iron, zinc & orthophosphate. If pH is (was) below 6.0 – add a 10 ppm slug of Corrosion inhibitor chemical to the system. Blowdown system heavily. Recheck for Fe, pH. |
| Increase blowdown and adjust pH with alkali to lower end of control range. | ||
| b. | Lab pH meter is out of calibration. | Calibrate meter. |
| c. | pH meter will not hold calibration. | Re: Instrument troubleshooting guide. |
| d. | pH probe is not working. | Replace pH probe & check warranty for return to manufacturer. |
| e. | pH meter will not hold calibration. | Re: Instrument troubleshooting guide. |
Problem-3: System pH is above Specification
| POSSIBLE SOURCE | CORRECTIVE ACTION | |
| a. | Acid feed system malfunction. | Verify acid feed system functionality – begin feeding acid manually if the acid feed system is malfunctioning Analyze for total hardness, and alkalinity. |
| Slug feed double the dosage of polymer. Increase the blowdown /or adjust the alkalinity with acid to the lower end of the M-alkalinity/pH control range. | ||
| b. | Blowdown measurement is not accurate, is shut, and/or is in operation. | Verify functionality of blowdown system. |
Problem-4: Recirculation water conductivity level is above the limit
| POSSIBLE SOURCE | CORRECTIVE ACTION | |
| a. | Increase the conductivity level in the makeup water. | If calcium or silica is high in the recirculating water, blowdown rate is (was) inadequate – increase blowdown rate. Increase the blowdown rate to control the ionic load. |
| b. | Blowdown valve is fully open but conductivity (cycles) continue to rise in the recirculating cooling water. | Blowdown line is fouled (plugged). Open bypass, free blowdown line, place in service & close bypass. |
| c. | Chemical overfeed. | Verify chemical federates. |
| d. | Blowdown valve is stuck in open position. | Repair blowdown system. |
Problem-5: Recirculating cooling water conductivity is below specification
| POSSIBLE SOURCE | CORRECTIVE ACTION | |
| a. | Tower basin overflow. | Verify functionality of tower make-up valve. |
| b. | Excessive use of recirculating cooling water in the process. | Verify usage of cooling water by all process users. |
