METHODS FOR PREVENTING CORROSION OF NON-PASSIVATED METALLIC BODY AND BOILER AND WATER-SUPPLY SYSTEM FOR BOILER

摘要

PROBLEM TO BE SOLVED: To prevent corrosion of a non-passivated metallic body such as a heat-transfer pipe of a boiler under the influence of water without using any corrosion inhibitor. SOLUTION: Corrosion in a once-through boiler 2 which generates steam by heating feed water fed via a series of water-supply route including an irrigation channel 8 and a supply channel 10 is prevented through a method comprising a step wherein feed water fed to the once-through boiler 2 is previously filtered using a filter 12 equipped with a membrane filter which traps corrosion-accelerating components in the once-through boiler 2 and is pervious to corrosion-preventing components in the once-through boiler 2. Here, the corrosion-accelerating components usually include sulfate and chloride ions while the corrosion-preventing components usually include silica. The membrane filter used in the filter 12 is, e.g. a nanofiltration membrane. COPYRIGHT: (C)2004,JPO&NCIPI