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V-1169 — Atmospheric Gas Oil Drum V-1169

Sulfur Recovery Unit · Atmospheric Gas Oil service · Installed Aug 28, 2000 (26 yrs in service)

High
Current Min. Thickness
0.951 in
t-min 1.184 in
Measured Corrosion Rate
14.71 mpy
ML-predicted: 15.32 mpy
Remaining Life
0.0 yrs
Next Inspection Due
Feb 20, 2027
Interval: 0.5 yrs (API 510)

UT Thickness Trend

Minimum CML reading per inspection vs. ASME Sec. VIII t-min

Vessel Specification

MaterialSA-240-316L Stainless
Design CodeASME BPVC Section VIII, Div. 1
Joint Efficiency0.85
Design Pressure389 psig
Design Temperature402 °F
Operating Pressure244 psig
Operating Temperature284 °F
Diameter85 in
Nominal Thickness1.335 in
Corrosion Allowance0.0938 in
H2S / Chloride46 / 289 ppm
Flow Velocity13.3 ft/s
Process pH6.41
InsulatedNo

Corrosion & Remaining-Life What-If

Adjust operating conditions to see the live model-predicted corrosion rate and implied remaining life

Live Prediction — What-If Model
15.97 mpy
Predicted corrosion rate under these conditions (+1.26 mpy vs. current measured rate)
Implied Remaining Life
0.0 yrs
Implied Reinspection Interval
0.5 yrs

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 — Naphthenic Acid Corrosion

API 571 §4.2.10

Aggressive, velocity-assisted corrosion in high-TAN crude fractions, most severe 450–750°F; low-alloy/carbon steel is far more susceptible than Mo-bearing or 316 SS.

Recommended inspection approach: UT thickness at high-velocity/turbulent locations; feed TAN monitoring; consider alloy upgrade per API 571 guidance.

Inspection History

UT thickness readings, most recent first

DateMethodCML CountAvg ThicknessMin CML Thickness
Aug 22, 2026UT Spot40.9545 in0.9505 in
Dec 31, 2025UT Grid (API 572)40.9615 in0.9459 in
Sep 21, 2022UT Spot41.0119 in1.0045 in
May 1, 2021UT Grid (API 572)41.0305 in1.0143 in
Feb 25, 2018UT Grid + RT41.0793 in1.0780 in
Mar 29, 2015UT Grid (API 572)41.1214 in1.1142 in
Aug 24, 2013UT Grid (API 572)41.1435 in1.1282 in
Jan 2, 2011UT Grid (API 572)41.1773 in1.1587 in
Jun 11, 2009UT Grid + RT41.2043 in1.1979 in
Apr 13, 2007UT Grid + RT41.2413 in1.2245 in
Sep 23, 2004UT Grid + RT41.2756 in1.2634 in
Jan 13, 2002UT Spot41.3180 in1.3025 in