陈金国

摘 要：对低压蒸发器流动加速腐蚀后泄漏的原因进行详细分析，并提出流动加速腐蚀后泄漏的处理对策。结果表明，4台余热锅炉低压蒸发器换管后，未再发生低压蒸发器出口集箱处弯头异常泄漏的事件;同时，对更换后的低压蒸发器管子进行壁厚测量检查，也未再发现管子壁厚减薄的现象，说明处理措施取得了较好的效果。

关键词：立式余热锅炉;低压蒸发器;流动加速腐蚀

中图分类号：TQ54 文献标识码：A 文章编号：1003-5168（2021）29-0039-03

Analysis and Treatment of Flow Accelerated Corrosion Failure of

Low Pressure Evaporator of Vertical Waste Heat Boiler

CHEN Jinguo

（China Shipping Fujian Gas Power Generation Co.， Ltd.， Putian Fujian 351100）

Abstract： The causes of leakage after flow accelerated corrosion of low-pressure evaporator are analyzed in detail， and the treatment countermeasures of leakage after flow accelerated corrosion are put forward. The results show that after the tubes of the low-pressure evaporators of the four waste heat boilers were changed， the abnormal leakage of the elbow at the outlet header of the low-pressure evaporator never occurred again; At the same time， the wall thickness of the replaced low-pressure evaporator pipe was measured and checked， and the phenomenon of pipe wall thickness thinning was not found again， and good results were achieved.

Keywords： vertical waste heat boiler;low pressure evaporator;flow accelerated corrosion

1 工程概況

某电厂一期建设4×350 MW的M701F燃气-蒸汽联合循环发电机组，采用单轴一拖一布置，余热锅炉选用无锡华光锅炉股份有限公司引进比利时CMI公司技术生产的立式余热锅炉，为三压再热、无补燃的立式自然循环锅炉，余热锅炉主要技术参数见表1。

4台余热锅炉分别于2008年和2010年陆续投运。从2014年开始，几台余热锅炉在机组运行过程中出现烟囱顶部排放口有白色水汽冒出的现象，且余热锅炉24 m层炉膛前部内有泄漏声，同时低压汽包水位下降异常。经停机后检查，发现低压蒸发器模块出口联箱靠近左右炉墙两侧非鳍片管的弯头陆续出现冲刷减薄破裂现象，造成机组停炉检修。为防止机组非计划停运，从受热面烟气流道、水循环、管材、运行工况等方面排查原因，并采取相应措施处理，避免了低压蒸发器模块泄漏问题。

2 低压蒸发器模块简述

低压蒸发器模块布置如图1所示。蒸发器进口、出口集箱均布置于炉前侧，在炉后侧……