改进型低氧处理精确加氧技术在超超临界机组的应用

Application of Improved Oxygenated Treatment on Ultra-Supercritical Unit with Precise Low Oxygen Content Dosing Technology

为防止给水系统、高压加热器疏水系统流动加速腐蚀,超(超)临界机组采用加氧处理技术很有必要。为减少对过热器、再热器氧化皮问题的担心,研发出适当降低给水p H值、精确控制加氧量的改进型低氧处理技术。相比以往的低氧处理方法,该技术能够提高凝结水精处理系统的经济性,防止高压加热器汽侧腐蚀和降低疏水含铁量,同样不额外增加蒸汽中的氧量,消除传统加氧工况对氧化皮剥落的影响,并兼有加氧处理的其他优点。所研发的改进型低氧处理技术在1 000 MW超超临界机组上应用效果良好,起到了对汽水系统全程保护的作用。

It is of vital importance to implement oxygenated treatment for （ultra） supercritical units to effectively inhibit flow accelerated corrosion in feed-water and high pressure heater drain systems. The improved oxygenated treatment with low oxygen content, appropriate feed-water pH value reduction and precise oxygen dosing technology is developed to solve the oxide scale problems in both the superheaters and the reheaters. Compared with the traditional oxygenated treatment using low oxygen content, this technology can further improve the economic efficiency of condensate polishing system, effectively inhibit flow accelerated corrosion in high pressure heater drain system and reduce its iron contents without any extra oxygen content increase in the steam, which not only eliminates the adverse effect of oxygen dosing on oxide scale exfoliation but also has the advantages of other oxygenated technologies. Its application on 1 000-MW ultra-supercritical unit shows good effects such that the whole water-steam circuit system is fully protected effectively.