Patent ID: 8277662

Claim:
A steam boiler apparatus comprising: a steam boiler adapted to heat boiler water to generate steam; a feed-water supply system having a feed-water supply line made of metal and adapted to supply feed-water for use as the boiler water, to the steam boiler therethrough; and a preheater adapted to heat the feed-water supply line by exhaust heat from the steam boiler, to heat the feed-water, wherein the feed-water supply system includes: a water-softener unit adapted to treat the feed-water using a cation exchange resin capable of trapping a water hardness component contained in the feed-water while releasing hydrogen ions into the feed-water, to remove the water hardness component from the feed-water; a degasifier unit adapted to remove dissolved gas contained in the feed-water after removing therefrom the water hardness component in the water-softener unit; an agent-adding unit adapted to add an agent containing an alkali metal hydroxide, into the feed-water after removing therefrom the dissolved gas in the degasifier unit and before being heated by the preheater, to neutralize the hydrogen ions from the cation exchange resin; and a recirculation device adapted to recirculate a part of the boiler water from the steam boiler to the feed-water after removing therefrom the dissolved gas in the degasifier unit and before being heated by the preheater, and mix the recirculated boiler water with the feed-water.