600MW空冷机组水汽品质的优化及成效

Optimization and Effects of Water-Steam Quality for 600-MW Air-Cooled Units

内蒙古达拉特发电厂4期工程2台600 MW燃煤、直接空冷机组汽轮机叶片存在明显积盐现象。经分析,其主要原因是机组在调试阶段洗硅效果不佳,运行期间给水pH值控制偏低。为此,确定了最佳的化学水处理运行工况,包括将给水处理方式由原来的AVT(R)改为AVT(O),通过锅炉热化学试验制定并采取了一系列运行改进措施,同时在凝汽器排气装置出口加装了强磁除铁器,使水汽品质得到了明显改善,2台机组水汽品质合格率分别由以前的92.3%和90.2%提高到现在的99.7%和99.2%。

Salification is observed on the turbine blades of Dalate Power Plant Phase IV Project in overhauls.The power plant is equipped with two 600-MW coal-fired,direct air-cooling units.The analysis indicates that it mainly results from the poor effect of silicon washing during the tuning stage and the low pH value of the feedwater during the operation.Therefore,an improved operation condition for chemical water treatment is determined,including the water treatment mode changed from the original AVT(R) to AVT(O).Through boiler thermal chemical tests,a series of improvement measures is developed and adopted in the operation.A magnet remover is also installed in the condenser exhaust device,which improves the water vapor quality significantly.The acceptable rate of the water vapor quality of the two units has been raised from 92.3% and 90.2% to 99.7% and 99.2% respectively.