600MW超临界锅炉末级过热器爆漏原因分析

湖南华电长沙发电有限责任公司600MW超临界锅炉在初带高负荷试运不到10h，发生末级过热器爆漏，其爆漏部位发生在中间第16屏、外数第10内圈管，而类似情况在同类型锅炉调试其间也曾多次发生。其原因为过热器二级减温器混合管的制造工艺用衬垫材质与设计要求不符，导致衬垫脱落并进入末级过热器进口联箱，引起末级过热器管部分堵塞而短期过热爆漏。因此，通过检查、清理减温器混合管衬垫可有效防止末级过热器失效损坏。

Cause analysis on the burst and leakage at final superheater of 600 MW supercritical boiler

The burst and leakage took place at the final superheater of 600 MW supercritical boiler, when the trial operation with high load was less than 10 hours. The faults were, mainly located at the 16th middle division and the 10th tube coil. Such failure often occurred in the commissioning of boilers alike. This mainly because of the inconsistence between the practical pad materials and the design requirements for the mixing tubes at the 2ha-stage desuperheater as a result, the fallen pad entered into the inlet header of final superheater, which resulted in the blockage, transient overheat and burst at final superheater. It was available to prevent the final superheater from bursting by checking and cleaning the pad of desuperheater mixing-pipe.