常熟发电厂1号炉高温再热器管屏变形原因分析

Causes Analysis on Panel Deformation of Hige Temp.Reheater in Changshu Power Plant Boiler No.1

对高温再热器管壁温度、烟气温度的实时监测和分析计算表明，高温再热器的管屏变形不是由管壁或工质温度超限引起，而是由于进／出口温度差，以及同屏各管进／出口温度偏差所产生的胀差引起。同屏管夹破坏是因管子膨胀不畅，管夹焊缝应力超过许用应力，管夹的焊接强度不够而拉裂造成；定位管与各屏外管套的垂直膨胀最不同而产生相对位移，形成定位管脱开后错位。

The real-time monitoring and analysis on temperature of high temp.reheater tube and flue gas indicate that panel deformation of high temp.reheater was notcaused by the over-high temp.of tubes or work medium,but by the expanding diffeiencesdue to inlet/outlet temp.difference and inlet/outlet temp.deviation of tubes in the samepanel.The tube clamp was cracked due to the impeded expanding of tubes,weld stress oftube clamp being beyond the allowable value and inadequate welding strength.Verticalexpanding difference between fixing tube and the outest loop of panels caused relativedisplacement,resulting in the release and consequently the dislocation of fixing tube.