Elucidation of the effect of organic amine additives on corrosion behavior of boiler equipment materials in power plants

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K04158
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 18010:Mechanics of materials and materials-related
• Research Institution: Shinshu University
• Principal Investigator: NIU LIBIN 信州大学, 学術研究院工学系, 准教授 (20262694)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 腐食 / ボイラ設備材料 / ボイラ水 / 有機アミン / 蟻酸 / 酢酸 / 塩化物イオン

Outline of Final Research Achievements

Various corrosion tests were carried out on STBA24, STBA12 low-alloy steels for boiler equipment and 13Cr steel for low-pressure steam turbine blades in the simulated boiler waters prepared with organic amines and the waters containing organic acids. Comparing with the conventional water treatment agent of ammonia, the corrosion rate of the low-alloy steels decreased in the simulated boiler waters added with the organic amines. Based on the analysis results of the corroded surfaces, the corrosion inhibition mechanism of the organic amine additives was discussed. Pitting corrosion and crevice corrosion of the 13Cr steel in chloride ions (Cl-) added boiler water was suppressed by the addition of acetic acid and formic acid into the test water. However, it is suggested that formic acid in chloride-containing boiler water is a factor that promotes the corrosion of STBA24 and its weldments over long-term service.

Free Research Field

工学

Academic Significance and Societal Importance of the Research Achievements

火力発電プラントのボイラ給水・補給水には水処理薬剤として各種有機アミンを使用する傾向が見られる。しかし、これらの有機アミンはボイラ設備材料の腐食挙動に与える影響が不明である。さらに、これらのアミンは熱分解により有機酸の蟻酸や酢酸などを生成し、プラント設備材料腐食の一要因になることも懸念されている。本研究では、火力発電プラントボイラ設備材料ならびに低圧蒸気タービン材料の腐食挙動に及ぼすこれらの有機アミンおよび有機酸の影響を解明し、得られた研究成果は火力発電プラントの安全運転などに貢献できる。