Effect of Scale in Steam Boiler

Water treatment should be performed to feedwater before to be supplied into steam boiler to remove scale content in feedwater. Bad treatment will cause a lot of scale content in feedwater. It can give bad effect in the steam boiler process as follow:

1.        Influence amount of heat loss in overall boiler.
Scale which be attached in inner surface of pressure part (tube and header) will block heat transfer by conduction from metal tube or header to water because scale in the middle position between metal and water has role as isolator. So, the blocking heat transfer will impact to amount of heat loss. Practically, 2 mm thickness of scale attached in the surface will make heat loss approximately 2% until 3%.

2.        Reduce efficiency in the steam boiler
Higher heat loss will influence lower efficiency of steam boiler because of less heat absorb in the furnace will make excessive fuel consumption and temperature of stack outlet

Water flow in inner tube also has function as cooler because temperature of water is very lower than temperature of firing. If scale occurs in inner surface of tube, cooling function will be reduced, so metal temperature will be higher than temperature design and will impact to overheat. This condition will lead to failure and damage in pressure part.

4.        Influence to corrosion forming
The deposit of scale will cause corrosion forming because scale composition can compound with metal tube or header to form corrosion.

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