某350 MW超临界机组给水铁含量超标原因分析及处理

Cause analysis and treatment of iron content of feed water exceeding the standard for a 350 MW supercritical unit

某350 MW超临界机组自完成168 h满负荷试运一年以来,给水铁含量长期超标。通过查定和分析发现,其主要由给水处理工况控制不当、除氧器加热汽源蒸汽品质差、高压加热器疏水管道冲刷腐蚀产物、汽泵前置泵汽蚀等原因所致。经采取有效措施处理后,给水含铁质量浓度稳定在2~4μg/L,达到含铁质量浓度小于5μg/L的标准要求。

The iron content of feed water has exceeded the standard for a long time, since the accomplishment of 168 h full load trial operation for a year in a 350 MW supercritical unit. It is found through assessment and analysis that the main causes are as follows：inappropriate working conditions of feed water treatment,low steam quality of deaerator heating steam sources, high erosion corrosion products from water pipeline, and the cavitation of steam pump and fore pump, etc.. After taking effective measures ,the iron content of feed water is stabilized at 2-4μg/L,which can meet the requirement of iron content less than 5μg/L standard.