Failure analysis of furnace tube cracking in synthetic ammonia unit
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.