低温再热器入口管道线状偏离机理分析

Mechanism research on linear deviation of low temperature reheater inlet piping

某新建300 MW火力发电机组短时试运行后,低温再热器入口管道发生大范围线状偏离,支吊架存在严重压死、过载等现象。为探究引起管道发生线状偏离的机理,本文通过对实际安装的恒力支吊架进行载荷测试试验,得到恒力支吊架存在较大的载荷偏差度及恒定度;通过管道静力模拟计算,得到试运行后管道垂直方向的线状偏离与实测基本吻合,在此状态下管道一次应力超标、端点推力及推力矩急剧增大。分析认为,引起动力管道发生线状偏离的因素较多,其中恒力支吊架载荷偏差度及恒定度过大造成支吊架输出载荷与管道自重不匹配是最关键因素。恒力支吊架的结构特点决定了其无法在冷、热态时保持输出载荷绝对恒定,建议在动力管道设计中要尽可能优化管道支吊方式,并在支吊架采购及日常维护中加强管理与监督。

After a short-term trial operation,the inlet piping of low temperature reheater of a newly-built 300 MW thermal power unit deviates widely,and the support-hangers are seriously crushed and overloaded.In order to explore the mechanism of pipeline linear deviation,load test of the installed constant support-hangers was carried out,it showed that large load deviation and constant degree exist in the support-hangers.The static simulation calculation of the pipeline indicated that the cold vertical displacement after the trial operation is basically consistent with the measured value,the primary stress of the pipeline in this state exceeds the allowable value,and the thrust and push torque of the end point increase sharply.The analysis shows that,there are many factors leading to the pipeline deviation of power piping,among which the mismatch between the support-hanger loads and the piping weight is the most critical one,which is caused by the large constant degree and load deviation of the constant hanger.The structural characteristics of the constant support-hanger determine that it can not maintain constant output load between the cold and hot state.It is suggested that in the design of the power piping,the arrangement of support-hangers on the pipeline should be optimized as far as possible,and the purchase and daily maintenance of support-hangers should be strengthened in the management and supervision.