Case study: Cracking occurred in a (UNS S32100) type austenitic stainless steel nozzle fitting at a low point in the reactor effluent piping in a Gasoil Hydrotreater unit following start up. Normal preventive measures had been taken. The failed sample was removed for metallurgical analysis and determination of mechanism(s).
Cases where alkaline-carbonate stress corrosion cracking (ACSCC) occurred, including a cold wall Fluid Catalytic Cracking (FCC) Unit regenerator and a mercaptan oxidation unit. This paper discusses work done to monitor on-going ACSCC risks through sour water sampling, chemical analysis, and ionic modeling.