为了查明合成氨单元开工加热炉炉管发生开裂失效的原因,采用多种检测方法对失效炉管进行了分析.根据裂纹形貌分析、材质化学成分分析、金相组织分析和裂纹填充物能谱分析等结果可以得出,失效炉管两处开裂的原因分别是湿硫化氢破坏和异种金属混入,炉管上部外壁的密集蚀坑则是由烟气硫酸露点腐蚀所致,基于炉管失效原因分析,提出了针对性的预防措施.
In order to identify the cracking causes of furnace tube in synthetic ammonia unit,multiple detection methods were applied to study the failed furnace tube.Based on the findings from crack morphology analysis,material chemical composition analysis,metallographic structure analysis and crack filler energy spectrum analysis,it can be concluded that the wet hydrogen sulfide damage and mixing of different metals were the root causes for two cracks in furnace tube.The dense corrosion pits on out-er wall at upper part of the furnace tube were caused by dew point corrosion of flue gas sulfuric acid.Concrete measures were put forward accordingly.