Sour service behavior of a 110ksi material was investigated in a range of production environments. Slow strain rate tests were performed at a strain rate of 510-7/s, in sweet as well as in sour production environments. The strain to failure in sweet environments is lower than the in-air values and is substantially lower in the presence of H2S.
Multiple leaks occurred with a carbon steel pipe carrying hot condensate water (300F and 140 psi). A root cause analysis was performed, including visual and metallographic examination of two failed samples chemical, analysis of weld metal and base metal and chemical analysis of water samples. Results show that flow accelerated corrosion (FAC) was the responsible mechanism leading to the failures.
The concept of using physics-based models for corrosion monitoring is still new although corrosion monitoring by use of hardware coupons and probes is well recognized. This paper describes the application in downstream related to crude unit overhead and demonstrates how the monitoring concept can be used and its benefits.