Failure analysis of falling film tube in industrial sodium hydroxide production line
CAI Xinnan1,2, KE Xian1,2, WANG Jintai1,2, YU Feng1,2, JIAO Zongju3, LIAO Xinyi1,2
1. Chong Qing Materials Research Institute Co., Ltd., Chongqing 400700, China; 2. National Engineering Research Center for Instrument Functional Materials, Chongqing 400700, China; 3. Beipei Power Supply Branch, State Grid Chongqing Electric Power Company,Chongqing 400700, China
Abstract：The liquid leakage was observed for one falling film tube in an industrial sodium hydroxide plant in China after service for half a year. It was unable to collect industrial sodium carbonate normally. In order to explore the failure reason of the falling film tube, the low magnification macroscopic morphology observation, surface morphology analysis, metallographic structure analysis and composition analysis of the failed parts were conducted by stereo microscope, scanning electron microscope (SEM), metallographic microscope (OM) and electron probe microanalysis (EPMA). The results showed that the failure of the falling film tube was caused by the stress corrosion cracking in the outer wall welding area due to the presence of the pollution element sulfur, which led to the through cracks in the welding area of the falling film tube. Finally, the leakage of soda solution was caused.
2023, Vol. 41 
