裂解装置急冷锅炉换热管开裂泄漏原因分析  

Study on Cracking Mechanism of Heat Exchange Pipes on Quenching Boiler

作　　者：陈婉娴 Chen Wanxian(Zhongke(Guangdong)Refinery&Petrochemical Company Limited,Zhanjiang 524076,China)

机构地区：[1]中科(广东)炼化有限公司,广东湛江524076

出　　处：《广东化工》2023年第13期115-118,共4页Guangdong Chemical Industry

摘　　要：某石化企业裂解装置的急冷锅炉换热管运行过程中发生开裂泄漏。本文通过对发生泄漏的换热管进行宏观观察、化学成分分析、机械性能分析、金相分析、断口形貌观察以及能谱分析等表征手段,结合现场工艺参数对失效原因进行分析。结果表明换热管焊缝裂纹的主导失效机制为热疲劳+振动疲劳,次要失效机制为碱应力腐蚀开裂。疲劳裂纹首先萌生于焊缝外表面根部未焊透部位的应力集中处,并在热疲劳和振动疲劳载荷的作用下,向内表面扩展,直至穿透管壁发生泄漏;碱应力腐蚀开裂则加速了裂纹的扩展。该换热管焊缝存在根部未焊透缺陷、硬度偏高是开裂的导因,锁底结构焊接接头形式设计不合理则为焊缝质量保证和缝隙腐蚀埋下了隐患,工艺操作上温度变化和流体诱导振动偏大则为开裂的载荷因素。The cracking mechanism of a heat exchange pipe on quenching boiler was studied via analysis of macro-observation,chemical composition,mechanical properties,metallographic,fracture morphologies and EDS,combining with field process parameters.The results turn out that the crack induced by stress concentration,which is originated from the outer-wall incomplete-penetration weld.Consequently,crack would be propagated under the interaction of thermal fatigue and vibrating fatigue until final failure.

关 键 词：急冷锅炉 节能减排 热疲劳 振动疲劳 

分 类 号：TK229[动力工程及工程热物理—动力机械及工程]