火电机组凝汽器不锈钢管泄漏原因分析

Leakage Analysis for Stainless Steel Pipes in Condenser of Thermal Power Generation Unit

135 MW机组凝汽器泄漏现象时有发生,为找到泄漏原因,进行停机检修。对凝汽器不锈钢管进行宏观和微观形貌检查,发现汽机侧不锈钢管存在多处泄漏点,泄漏不锈钢管大致分为刮痕状与凹陷穿孔状两种;对该机组凝汽器管管材和循环水水质进行检验,并对管内垢样进行微观形貌及能谱分析。结果表明:凝汽器泄露的主要原因为微生物粘泥的沉积作用加速点蚀的形成并导致垢下腐蚀;纽带的有效旋转在一定程度上使管内壁产生机械磨损。

The condenser of a 135 MW thermal power generation unit leaked from time to time.In order to find out the leakage cause,the macro and micro morphology of the stainless steel pipes in the condenser was inspected during the shutdown and maintenance.There are several leakage points in the stainless steel pipes at the steam turbine side,and the leakage points mainly present the following two features:being scratched and being dented and perforated.In addition,the material of the condenser pipes and the quality of the circulating water were tested,and micro morphology observation and energy spectrum analysis the scale deposit in the pipes were carried out.The results show that the main reason for the condenser leakage is that the deposition of microbial slime accelerated pitting corrosion and led to corrosion under scale deposit,and the effective rotation of the ties caused mechanical wear on the inner wall of the pipes to a certain extent.