某燃料气换热器在运行过程中发现其换热管束出现多处鼓包开裂现象, 为查明鼓包开裂原因, 对换热管束进行了宏观和微观检验、化学成分分析、金相检验和扫描电镜分析。结果表明: 换热管内存在压力波动、换热管壁厚不均匀、壳程介质H2S含量较高以及换热管材料中存在,夹杂物都是导致其鼓包开裂的原因; 换热管壁厚较薄处容易形成应力集中, 使该处硫化氢腐蚀严重, 壁厚进一步减薄, 当壁厚减薄达到一定值时, 在管内压力波动作用下形成鼓包, 随着腐蚀的加剧和压力波动的继续作用, 最终导致换热管于鼓包处产生裂纹, 进而发生泄漏。

Much bulging and cracking phenomenon was found on the tube bundles of a fuel gas heat exchanger during operation process. Means such as macro examination, micro examination, chemical compositions analysis, metallographic analysis and scanning electron microscope analysis were used to analyze the bulging and cracking reason. The results show that the existence of pressure fluctuation in the tube, non-uniform wall thickness of the tube, high H2S concentration of the shell pass medium and more inclusions in the tube material were all reasons for the bulging and cracking of the heat exchanger tube bundles. Stress concentration formed easily at the thinner wall thickness positions of the tube, which aggravated the H2S corrosion at these positions and reduced the wall thickness further. When the wall thickness was reduced to a certain value, bulges were formed under the action of pressure fluctuation. Then cracks were formed at the bulging position and leakage happened with the aggravation of corrosion and continous action of pressure fluctuation.