直接空冷300MW机组凝汽器流动加速腐蚀研究

STUDY ON FLOW-ACCELERATED CORROSION OF CONDENSER FOR DIRECT-AIR-COOLED 300 MW UNIT

介绍了华能榆社发电有限公司(榆社电厂)直接空冷300MW机组凝汽器发生严重流动加速腐蚀(FAC)的现象,分析认为其原因为水平配汽管表面形成疏松Fe3O4膜,以及配汽管过渡段的蒸汽扰动和湿蒸汽水滴的冲击。提高给水和金属表面液膜中的pH值有利于抑制流动加速腐蚀和降低腐蚀产物对热力系统的影响,但存在加氨量显著增加和影响后续精除盐系统等问题。

The phenomenon of serious flow- accelerated corrosion （FAC） occurred in condenser of air- cooled 300 MW unit in Huaneng Yushe Power Generation Co Ltd has been presented,and the causes leading to FAC being analysed. It is believed that the causes are the Fea 04 film on surface of the horizontal steam distribution pipes being oxidized,as well as the steam disturbance and the impulse of wa ter drops contained in wet steam passing through the transitional section of steam distritution pipes. Enhancing pH value of feed - water and liquid film on metal surface is helpful to suppress FAC and decrease the influence of corrosion products upon the thermal system, but the amount of added ammonia has to be substantially increased,and affecting the operation of post- continued fine desalting system.