CONCEPT DEMONSTRATION
66Phillips 66Vessel Integrity Intelligence
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V-1134 — Steam Column V-1134

Sulfur Recovery Unit · Steam service · Installed Aug 31, 1991 (35 yrs in service)

Low-Medium
Current Min. Thickness
0.485 in
t-min 0.424 in
Measured Corrosion Rate
3.19 mpy
ML-predicted: 5.03 mpy
Remaining Life
19.3 yrs
Next Inspection Due
Apr 12, 2036
Interval: 9.7 yrs (API 510)

UT Thickness Trend

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

Vessel Specification

MaterialSA-240 Duplex 2205
Design CodeASME BPVC Section VIII, Div. 2
Joint Efficiency0.85
Design Pressure143 psig
Design Temperature674 °F
Operating Pressure97 psig
Operating Temperature619 °F
Diameter117 in
Nominal Thickness0.598 in
Corrosion Allowance0.1250 in
H2S / Chloride44 / 284 ppm
Flow Velocity1.7 ft/s
Process pH6.09
InsulatedYes

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
7.30 mpy
Predicted corrosion rate under these conditions (+4.11 mpy vs. current measured rate)
Implied Remaining Life
8.4 yrs
Implied Reinspection Interval
4.2 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 — Corrosion Under Insulation (CUI)

API 571 §4.3.5

Localized external corrosion beneath insulation where moisture is trapped, most severe in the 140–250°F operating band.

Recommended inspection approach: Insulation removal at high-risk locations (nozzles, low points), profile radiography, or guided-wave UT screening per API 570/RP 583.

Inspection History

UT thickness readings, most recent first

DateMethodCML CountAvg ThicknessMin CML Thickness
Aug 22, 2026UT Spot80.4896 in0.4852 in
Sep 30, 2025UT Grid + RT80.4897 in0.4821 in
Jan 1, 2023UT Grid (API 572)80.4963 in0.4939 in
Jan 31, 2020UT Spot80.5084 in0.4980 in
Oct 12, 2017UT Spot80.5150 in0.4953 in
Apr 8, 2015UT Spot80.5249 in0.5059 in
Jun 16, 2012UT Grid + RT80.5355 in0.5232 in
Dec 24, 2009UT Grid (API 572)80.5407 in0.5350 in
Nov 4, 2007UT Grid + RT80.5484 in0.5384 in
Mar 13, 2006UT Grid + RT80.5540 in0.5364 in
Dec 15, 2002UT Grid (API 572)80.5611 in0.5468 in
Sep 7, 1999UT Spot80.5750 in0.5658 in
Apr 2, 1997UT Spot80.5831 in0.5819 in
Mar 29, 1995UT Grid + RT80.5886 in0.5878 in
Aug 4, 1993UT Grid + RT80.5918 in0.5812 in