V-1118 — Wet H2S Gas Column V-1118
Hydrocracker · Wet H2S Gas service · Installed Aug 30, 1995 (31 yrs in service)
UT Thickness Trend
Minimum CML reading per inspection vs. ASME Sec. VIII t-min
Vessel Specification
Corrosion & Remaining-Life What-If
Adjust operating conditions to see the live model-predicted corrosion rate and implied remaining life
What-if model: standardized Ridge regression, R² 0.56 on held-out fleet data (3.25 mpy MAE). Runs entirely client-side for instant feedback — see Model Insights for the full fleet-scale ensemble model used for official predictions.
Governing Damage Mechanism — Wet H2S Damage (SSC/HIC)
API 571 §4.5.1
Hydrogen-induced cracking (HIC) and sulfide stress cracking (SSC) in carbon/low-alloy steel exposed to wet H2S service. Not detectable by thickness monitoring alone.
Recommended inspection approach: Wet fluorescent magnetic particle (WFMT) and UT shear-wave/AUBT surveys in addition to routine UT thickness, per API RP 571 and NACE SP0296.
This mechanism is crack-dominant — thickness monitoring alone will not detect it. See Standards & Documentation for the full NDE requirement.
Inspection History
UT thickness readings, most recent first