| 摘要 |
PROBLEM TO BE SOLVED: To obtain a water treatment chemical for a boiler which contributes stable operation of a boiler during a normal operation, shutdown and startup, by preparing the chemical from aliphatic carboxylic acid and aldonic acid of heptose or hexose. SOLUTION: This water treatment chemical for a boiler consists of a first chemical comprising one or more kinds of aliphatic carboxylic acids or salts of these and a second chemical comprising one or more kinds of aldonic acids of heptose or hexose or salts of these orδ-lactone which can be hydrolyzed into aldonic acid under alkali conditions. The multiple effects of these chemicals give an enough corrosion preventing effect even with low concn. of the chemicals, Therefore, this water treatment chemical for a boiler shows an enough effect not only for normal operation but for a period when the operation of the boiler is stopped or started, although the quality of water becomes unstable and easily causes corrosion failure in the water system of the boiler in this period. The weight ratio of the aliphatic carboxylic acid, heptose and hexose in the chemical is preferably controlled to (1 to 2):(1 to 2):(1 to 2).
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