直接空冷凝汽器运行腐蚀原因分析及控制策略

国内直接空冷机组普遍存在凝汽器运行腐蚀的情况，虽然通过设置凝结水除铁装置可使给水含铁量达标，但直接空冷凝汽器的运行腐蚀问题没有得到根本解决。分析其腐蚀原因主要是给水碱化剂一一一氨在凝汽器初凝液中的分配系数太低，以及初凝液中的酸性阴离子富集，使设备材料在低pH值条件下发生腐蚀。试验结果表明:可通过在凝汽器排汽中辅助加入微量有机碱化剂或提高给水加氨量的方法，达到降低直接空冷凝汽器运行腐蚀的目的;从腐蚀控制和安全运行方面考虑，凝汽器排汽中加入微量有机碱化剂的方法更优。

Corrosion and Protection of Air-Cooled Condensers in Thermal Power Plant

The corrosion of air-cooled condensers (ACC) commonly exists in the operating units in China. Though the ferric concentration of feedwater can be made to meet the standards by installing deferrization facilities, the ACC corrosion is not solved thoroughly. In this paper, the causes of such corrosion are analyzed. The conclusion of the analysis is that it is the extra low partition coefficient of ammonia and high acidic anion in the initial condensate that makes the corrosion happen at low pH values. The test results show that the ACC corrosion can be controlled using the methods of either adding a few organic base to the exhaust steam or raising the ammonia concentration of the feedwater; while considering the corrosion control and operation safety, the former one is a better option, in order to control the corrosion and ensure the ACC operation safely, it is better to add a few organic base to the exhaust steam than others.