State reasons for scale formation in boilers. Reasons and effects.

Presence of calcium and magnesium carbonates, sea water ingress, dissolved solids, overdosing, use of shore water, improper or inadequate chemical dosing, insufficient blow down. Effects- low conductor of heat, reduction in heat transfer, overheating of tubes, boiler collapse, steam production reduces, thermal efficiency reduces, quality of steam reduces, pitting corrosion, acidic corrosion.