As a result of a Carbonate Stress Corrosion Cracking (CSCC) event at one refinery an investigation was made into the cause and mitigation of CSCC. This paper outlines the information obtained and the development of tools that could be utilized by other refinery fluidized catalytic cracker units (FCCU's) to better assess risk of CSCC.
This paper provides an introduction on carbonate cracking and Los Angeles refinery’s recent experience with this corrosion mechanism. Also included in this paper is the methodology used for developing a risk assessment for equipment and piping susceptible to carbonate stress corrosion cracking in a fluid catalytic cracking unit (FCCU) gas plant.
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.