V-1157 — Caustic Wash Column V-1157
Alkylation Unit · Caustic Wash service · Installed Aug 25, 2013 (13 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 — Chloride Stress Corrosion Cracking (Cl-SCC)
API 571 §4.5.2
Cracking of austenitic stainless steel exposed to chlorides above roughly 140°F under tensile stress; not a thickness-loss mechanism.
Recommended inspection approach: Surface/near-surface NDE (PT, ECT) at susceptible welds and CUI-prone insulated stainless piping; chloride source control.
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