固定管板式换热器管束腐蚀失效分析

Analysis of Corrosion Failure of Heat Exchanger Tubes

采用扫描电镜、能谱仪（EDS）及x射线衍射仪（XRD）等仪器设备，对某化工装置用固定板管式换热器管柬进行了腐蚀失效分析。分析表明：管柬材质实际碳质量分数仅为0．119％，低于设计材质20钢的标准要求，但对腐蚀性能影响较小；管柬腐蚀后整体壁厚发生减薄，大部分约为1．6～1．9mm，低于初始壁厚2mm；管束气侧只有轻微浮锈，水侧结垢严重，发生了腐蚀穿孔，其腐蚀产物主要呈褐色和黑色，成分主要为铁的氢氧化物和氧化物。可以判断。该换热器管束在近海引用循环水环境中发生了均匀腐蚀伴随局部腐蚀穿孔，这种腐蚀主要是由循环水的溶解氧、氯离子及微生物共同作用形成。

The corrosion failure analysis of tubes in the fixed tube - sheet heat exchanger of a chemical plant was performed by using SEM, EDS and XRD. The results of analysis showed the carbon in the tube material was only 0. 119 m%, which was lower than the specification of 20# steel. But it had little impact on the corrosion resistance performance. The thickness of the tubes was reduced to 1.6 - 1.9ram, which was 2 mm thinner than the primary thickness ; There was a little rusting on the gas side of the tubes and water side suffered from serious fouling. The corrosion failure occurred. The corrosion products were mainly brown and black scaling mainly composed of oxide and hydrate of irons. It can be concluded that the uniform corrosion and corrosion failure have occurred on the tubes from using offshore cooling water. The corrosion was mainly caused by oxygen, chlorine ion and microorganisms in the water.