CONCEPT DEMONSTRATION
66Phillips 66Vessel Integrity Intelligence
← Vessel Registry

V-1217 — Caustic Wash Vessel V-1217

Sulfur Recovery Unit · Caustic Wash service · Installed Aug 24, 2016 (10 yrs in service)

Low-Medium
Current Min. Thickness
0.467 in
t-min 0.378 in
Measured Corrosion Rate
0.95 mpy
ML-predicted: 1.69 mpy
Remaining Life
60+ yrs
Next Inspection Due
Aug 19, 2036
Interval: 10.0 yrs (API 510)

UT Thickness Trend

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

Vessel Specification

MaterialSA-387-11 Cl.2 (1.25Cr-0.5Mo)
Design CodeASME BPVC Section VIII, Div. 1
Joint Efficiency0.85
Design Pressure115 psig
Design Temperature268 °F
Operating Pressure91 psig
Operating Temperature238 °F
Diameter99 in
Nominal Thickness0.477 in
Corrosion Allowance0.0625 in
H2S / Chloride30 / 3118 ppm
Flow Velocity20.7 ft/s
Process pH6.67
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
0.72 mpy
Predicted corrosion rate under these conditions (-0.23 mpy vs. current measured rate)
Implied Remaining Life
60+ yrs
Implied Reinspection Interval
10.0 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 — 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

DateMethodCML CountAvg ThicknessMin CML Thickness
Aug 22, 2026UT Grid + RT60.4693 in0.4670 in
Jul 12, 2025UT Grid + RT60.4686 in0.4568 in
Jul 27, 2022UT Grid (API 572)60.4697 in0.4524 in
Sep 18, 2019UT Grid (API 572)60.4771 in0.4605 in