지역난방 첨두부하보일러 대류부 부식 파손 분석

• Published in: Corrosion science and technology Vol. 18; no. 2; pp. 55 - 60
• Main Authors: 김영수, Youngsu Kim, 채호병, Hobyung Chae, 홍민기, Minki Hong, 송민지, Min Ji Song, 조정민, Jeongmin Cho, 김우철, Woo Cheol Kim, 하태백, Tae Baek Ha, 이수열, Soo Yeol Lee
• Format: Journal Article
• Language: Korean
• Published: 한국부식방식학회 30.04.2019
• Subjects: Dew point corrosion; District heating system; IRIS inspection; PLB convection; Turbulator; 금속공학; Turbulator; Dew point corrosion; District heating system; IRIS inspection; PLB convection
• ISSN: 1598-6462; 2288-6524

Corrosion failure in the convection part of peak load boiler (PLB) of the district heating system led to water leakage. Herein, Internal Rotary Inspection System (IRIS) inspection was employed to examine wall thinning and the cause of leakage in the flue tube. The corrosive products of the turbulator and tube were investigated using scanning electron microscope combined with energy dispersive spectroscopy, X-ray diffraction, and inductively coupled plasma (ICP). Majority of the serious corrosion damage was observed near the turbulator located in the upper flue tube. ICP analysis of the boiler water revealed oxide formation of sodium chloride in the lower end part of the flue tube. A cross-sectional view of the turbulator revealed the presence of double-layers of the oxide film, indicating environmental change during operation associated with water leakage. The outer surface of the turbulator consisted of the acid oxides such as NO x and SO x along with sodium and chloride ions. Dew-point corrosion is hypothesized as the main cause for the formation of acid oxides in the region of contact of the flue tube and the turbulator.