350MW机组汽包水位波动大的分析及处理

Analysis and Treatment of Large Fluctuation of Drum Water Level in 350MW Unit

通过对某厂4号机组汽包水位波动大的原因进行分析,得出4号汽轮机高压调节阀门阀位变化后导致主蒸汽流量大幅波动,汽包水位自动调节不及时,给水跟踪品质差导致汽包水位大幅波动。采取降低辅助蒸汽联箱压力的处理方法,使汽包水位波动得到了较大程度的改善,由-30～+65mm降到-22～+22mm。提出采用四段抽汽为带给水泵汽轮机供汽;在冬季供暖等特殊工况无法使用四段抽汽供汽时,降低辅助蒸汽联箱压力;在运行中严密监视锅炉给水流量的变化,保持给水流量与主蒸汽流量平衡,控制汽包水位在合理范围内等措施。

By analyzing the fluctuation of drum water level in No.4 unit of a certain plant,it is concluded that the change of the valve position of No.4 steam turbine high-pressure control valve leads to a large fluctuation of the main steam flow,the automatic adjustment of the drum water level is not timely,and the poor water supply tracking quality leads to the drum water level great fluctuations.The treatment method to reduce the auxiliary steam header pressure has greatly improved the water level fluctuation of the drum,from-30-＋65 mm to-22-＋22 mm.Proposed to use four-stage extraction to provide steam for the pump turbine.When the four-stage extraction steam supply cannot be used under special conditions such as heating in winter,the auxiliary steam header pressure shall be reduced.Closely monitor changes in boiler feed water flow during operation,maintain balance between feed water flow and main steam flow,and control the level of drum water level within a reasonable range.