V-1179 — Crude Oil Drum V-1179

Sulfur Recovery Unit · Crude Oil service · Installed Aug 28, 2002 (24 yrs in service)

Critical

Current Min. Thickness

0.387 in

t-min 0.594 in

Measured Corrosion Rate

14.25 mpy

ML-predicted: 11.80 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 Duplex 2205

Design CodeASME BPVC Section VIII, Div. 2

Joint Efficiency0.85

Design Pressure329 psig

Design Temperature487 °F

Operating Pressure225 psig

Operating Temperature385 °F

Diameter76 in

Nominal Thickness0.746 in

Corrosion Allowance0.0938 in

H2S / Chloride24 / 74 ppm

Flow Velocity8.6 ft/s

Process pH4.16

InsulatedNo

Corrosion & Remaining-Life What-If

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

Operating Temperature385°F

H2S Concentration24 ppm

Chloride Concentration74 ppm

Flow Velocity8.6 ft/s

Process pH4.16

Insulated (CUI potential)

MaterialDamage Mechanism

Live Prediction — What-If Model

10.84 mpy

Predicted corrosion rate under these conditions (-3.41 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 — High-Temperature Sulfidation

API 571 §4.2.11

Reaction of sulfur compounds with steel at high temperature (>500°F) in the absence of water; rate governed by sulfur content, temperature, alloy content.

Recommended inspection approach: UT thickness per Modified McConomy-curve risk ranking; RT/UT at known high-rate locations identified by process simulation.

Inspection History

UT thickness readings, most recent first

Date	Method	CML Count	Avg Thickness	Min CML Thickness
Aug 22, 2026	UT Spot	6	0.4016 in	0.3869 in
Dec 10, 2025	UT Grid + RT	6	0.4138 in	0.4096 in
Dec 13, 2023	UT Grid (API 572)	6	0.4407 in	0.4331 in
Feb 9, 2021	UT Spot	6	0.4854 in	0.4720 in
Nov 7, 2018	UT Grid + RT	6	0.5196 in	0.5144 in
Apr 3, 2017	UT Grid (API 572)	6	0.5416 in	0.5368 in
Sep 29, 2015	UT Grid (API 572)	6	0.5592 in	0.5577 in
Jul 20, 2012	UT Grid (API 572)	6	0.6053 in	0.6038 in
Mar 7, 2010	UT Grid (API 572)	6	0.6344 in	0.6173 in
Jul 3, 2008	UT Grid + RT	6	0.6625 in	0.6609 in
Sep 15, 2006	UT Grid + RT	6	0.6908 in	0.6821 in
Dec 15, 2004	UT Grid (API 572)	6	0.7129 in	0.7038 in