Various forms of water side Corrosion: Causes & Prevention

During operation and idle period of boilers, various types of corrosion problems are encountered. The problems arise mainly due to the interaction of metal with the fluids (water, steam, condensate, air) circulating in the boiler. The outside i.e., the fire side corrosion problems occur mainly due to the interaction of constituents of fuel with
metal surface. These corrosive constituents interact with the metal surface to form low melting point compounds
which results in catastrophic failure of the components of the boiler. The fire side corrosion problem has been dis-cusseed by the other speakers. The present talk will be
limited to the various forms of corrosion problems expe-rienced in water side of boilers; their causes, mechanisum and control. Before, I go in detail about the subject, it will be pertinent here to describe in brief the corrosion reactions that occur at the interface of a metal and electrolyte.