Some Boiler Tubes Crack Reason Analysis

Abstract:

Aiming at some boiler tubescrack in a power plant, the element composition and the valence of elements in corrosion products on the outer surfaces of the boiler tubes were analysed by Scanning Electron Microanalyzer (SEM) and X-ray Photoelectron Spectroscopy (XPS), and the corrosion reason and mechanism of the outer surfaces of the boiler tubes were studied.The results showed as follows. (1)The content of element S in the corrosion products on the outer surfaces of the fire side boiler tubes was bigger than that in the corrosion products on the outer surfaces of the back side boiler tubes and the corrosion of the outer surfaces of the fire side boiler tubes was more serious than that of the outer surfaces of the back side boiler tubes. (2) the element S in the corrosion products existed in the form of sulfate (SO₄^2-), because the valence of S in the corrosion products on the outer surfaces of the fire side boiler tubes and the back side boiler tubes was +6, not-2. (3) the element Fe in the corrosion products on the outer surfaces of the fire side boiler tubes and the back side boiler tubes existed in the form of Fe₃O₄, Fe₂O₃ or Fe₂(SO₄)₃. (4) The corrosion of the boiler tubes was induced by sulphate under high temperature, and aggravated with the temperature of the outer surfaces of the boiler tubes elevated.

• Periodical: Applied Mechanics and Materials (Volumes 405-408)
• Pages: 3253-3258
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.405-408.3253
• Online since: September 2013
• Authors: Ling Pan, Xue Jun Xie, Jun Shen, Zhao Li, Rui Wang, Yang Yang, Ke Ru Peng
• Keywords: Boiler Tubescrack, Corrosion Induced by Sulphate, Surface Analysis

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