A hard coating deposit on the heat transfer surface of the boiler is called scaling. Boiler scale is caused by precipitation of TDS (calcium, magnesium, iron, silica etc.) in the boiler.
1. As scale is insulator of heat it reduces heat transfer leading to heat loss
2. Overheating of metal surface
3. Higher stack temperature
4. Higher fuel consumption
5. Increase maintenance
1. Pretreatment of boiler water by external water treatment i.e. demineralization & reverse osmosis etc.
2. Using Boiler water treatment chemicals
3. Treatment with polymeric dispersants & phosphates
4. Optimum boiler blowdown