Cause Analysis and Treatment of High Temperature Reheat Steam Pipe Sinking in 350 MW Supercritical Unit
After a period of operation,a large range of subsidence was found in the boiler side branches of high temperature reheat steam pipe of a 350 MW supercritical unit.Most pointers of continuously arranged constant spring hangers were beyond the lower limit position.Combined with field inspection and measurement,the stress calculation and analysis of pipeline under multiple working conditions were carried out.The results show that:The abnormal X-angular displacement and Z-linear displacement at the port of the outlet header are the main reasons for the pipe sinking,which are caused by the deformation and uneven deformation of the tube panel of the high temperature reheater with wing wall structure of the circulating fluidized bed boiler in this unit.The load deviation degree and constant degree of constant hangers exceed the limit is the secondary reasons for the pipeline subsidence.On the premise of not replacing the deformed heating surface tube panel,the working state of the pipeline and the support hangers are improved by making full use of pipeline flexibility to develop treatment scheme,and the stress level of the piping system is optimized.At the same time,the solutions to the problems of tube panel deformation and pipe subsidence in the later stage are put forward.The research provides reference for the design,maintenance and displacement anomaly troubleshooting of pipelines of similar units.
pipeline subsidencestress analysiscirculating fluidized bed boilerwing walldeformation
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