Brief descriptions of the mechanisms of common types of corrosion attacks in petrochemical and refinery environments viz. Wet H2S, Caustic, Amine, Carbonate corrosion and cracking.
Jigneshkumar J. Desai / Ashik S. Murthy / Cathleen Shargay
This paper gives brief descriptions of the mechanisms of common types of corrosion attacks in petrochemical and refinery environments viz. Wet H2S, Caustic, Amine, Carbonate corrosion and cracking. It then provides suggested guidelines for classifying the severity of the Wet H2S services and for all the listed services, accordingly provides a ready reckoner tool for Design Engineers to prescribe control measures to mitigate these risks. The control measures fall into three categories. The first is added material requirements such as mill heat treatments, chemistry restrictions, or additional requirements on material physical properties. The second class of control measures involves fabrication steps such as heat treatment, testing and inspection. Even with these practices, for some of the mechanisms, it is recommended to also have process or operational controls which are typically applied as Integrity Operating Windows (IOW), and it is beneficial to highlight these IOWs on the Materials Selection Diagram (MSD) and Piping and Instrumentation Diagrams (P&ID). Examples are velocity limit in amine services or temperature limits in caustic service. Collectively, these three categories of practices mitigate the risks associated with these corrosive services.
Key words: Wet H2S, SSC, HIC, SOHIC, Amine, Caustic, SCC, ACSCC, Materials Selection, Integrity Operating Window, IOW.