氨蒸发器换热管爆管原因分析  

Cause analysis of heat exchange tube burst of ammonia evaporator

作　　者：韩冰[1] 

机构地区：[1]中国石化集团南京化学工业有限公司化工机械厂,江苏南京210048

出　　处：《能源化工》2015年第6期68-72,共5页Energy Chemical Industry

摘　　要：针对某公司合成氨厂一台氨蒸发器发生的换热管爆管事故,分析了换热管发生爆裂的原因。对爆裂的换热管进行了外观检查、化学成分分析、力学性能检测、断口微观形貌观察、金相检查,结果表明:换热管化学成分合乎标准要求,金相组织正常,换热管内、外表面没有明显被腐蚀的痕迹。根据裂纹和断口形貌分析,排除了应力腐蚀、疲劳腐蚀或超压造成的爆裂,确定断裂口具有脆性断裂的特征。对设备的工艺条件进行了分析,认为导致换热管爆裂的主要原因是与换热管外表面接触的液氨温度降低,使材料的脆性增大,最终导致材料低温脆断。Aiming at a heat exchange tube burst accident that occurs in an ammonia evaporator of ammonia synthesis plant,the causes of heat exchange tube burst are analyzed. A series of inspection is carried out for the busted heat exchange tube including appearance inspection,chemical composition analysis,mechanical property detection,microstructure observation of fracture and metallographic examination. The results show that the chemical composition of the heat exchange tube is fit for the standard,the metallographic structure is regular,and the internal and external surface has no trace of corrosion. According to the morphology analysis of crack and fracture,the burst caused by stress corrosion,fatigue corrosion or overpressure is excluded,and the feature of brittle rupture in the breakage site is determined. Based on discussing the technical conditions of the ammonia evaporator,it is found that if the temperature of liquid ammonia which contact with the external surface of the tube decreases,the friability of the material will increase greatly. It is thought that brittle failure due to low temperature is the main cause of heat exchange tube burst.

关 键 词：氨蒸发器 爆管 脆性断裂 低温脆性 解理断裂 

分 类 号：TQ051.5[化学工程]