V-1336 — Sour Water Drum V-1336

Sulfur Recovery Unit · Sour Water service · Installed Aug 29, 1997 (29 yrs in service)

Medium

Current Min. Thickness

0.881 in

t-min 0.804 in

Measured Corrosion Rate

1.65 mpy

ML-predicted: 5.08 mpy

Remaining Life

46.7 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-240-304L Stainless

Design CodeASME BPVC Section VIII, Div. 1

Joint Efficiency1.00

Design Pressure363 psig

Design Temperature539 °F

Operating Pressure244 psig

Operating Temperature347 °F

Diameter73 in

Nominal Thickness0.935 in

Corrosion Allowance0.0938 in

H2S / Chloride543 / 182 ppm

Flow Velocity3.7 ft/s

Process pH5.53

InsulatedNo

Corrosion & Remaining-Life What-If

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

Operating Temperature347°F

H2S Concentration543 ppm

Chloride Concentration182 ppm

Flow Velocity3.7 ft/s

Process pH5.53

Insulated (CUI potential)

MaterialDamage Mechanism

Live Prediction — What-If Model

6.35 mpy

Predicted corrosion rate under these conditions (+4.70 mpy vs. current measured rate)

Implied Remaining Life

12.2 yrs

Implied Reinspection Interval

6.1 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 — CO2 (Sweet) Corrosion

API 571 §4.2.2

Carbonic-acid corrosion from dissolved CO2 in aqueous phases; rate peaks around 100–160°F and increases with velocity.

Recommended inspection approach: UT thickness grid focused on low points and water dropout locations; monitor produced-water chemistry.

Inspection History

UT thickness readings, most recent first

Date	Method	CML Count	Avg Thickness	Min CML Thickness
Aug 22, 2026	UT Spot	6	0.8866 in	0.8811 in
Jun 21, 2026	UT Grid (API 572)	6	0.8889 in	0.8799 in
Apr 29, 2023	UT Grid (API 572)	6	0.8916 in	0.8774 in
Mar 20, 2021	UT Spot	6	0.8968 in	0.8930 in
Sep 15, 2019	UT Grid + RT	6	0.8978 in	0.8912 in
Jan 5, 2018	UT Spot	6	0.9000 in	0.8914 in
May 13, 2015	UT Spot	6	0.9081 in	0.8986 in
Apr 18, 2013	UT Grid + RT	6	0.9086 in	0.8928 in
Mar 14, 2010	UT Spot	6	0.9160 in	0.9041 in
Feb 14, 2007	UT Grid (API 572)	6	0.9185 in	0.9003 in
Jul 29, 2004	UT Grid (API 572)	6	0.9228 in	0.9081 in
Mar 9, 2002	UT Spot	6	0.9276 in	0.9086 in
Feb 5, 1999	UT Spot	6	0.9333 in	0.9291 in