V-1057 — Sour Water Drum V-1057

Alkylation Unit · Sour Water service · Installed Aug 29, 1999 (27 yrs in service)

Critical

Current Min. Thickness

0.107 in

t-min 0.190 in

Measured Corrosion Rate

8.57 mpy

ML-predicted: 3.05 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-240-304L Stainless

Design CodeASME BPVC Section VIII, Div. 2

Joint Efficiency0.85

Design Pressure78 psig

Design Temperature229 °F

Operating Pressure47 psig

Operating Temperature147 °F

Diameter69 in

Nominal Thickness0.347 in

Corrosion Allowance0.0938 in

H2S / Chloride598 / 24 ppm

Flow Velocity12.3 ft/s

Process pH7.55

InsulatedNo

Corrosion & Remaining-Life What-If

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

Operating Temperature147°F

H2S Concentration598 ppm

Chloride Concentration24 ppm

Flow Velocity12.3 ft/s

Process pH7.55

Insulated (CUI potential)

MaterialDamage Mechanism

Live Prediction — What-If Model

4.30 mpy

Predicted corrosion rate under these conditions (-4.27 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 — 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	0.1162 in	0.1073 in
Jul 30, 2026	UT Grid + RT	6	0.1138 in	0.0987 in
Sep 15, 2023	UT Grid + RT	6	0.1426 in	0.1273 in
Jan 19, 2021	UT Spot	6	0.1613 in	0.1534 in
Jan 29, 2019	UT Spot	6	0.1786 in	0.1716 in
Apr 30, 2016	UT Grid (API 572)	6	0.2045 in	0.1884 in
Jun 17, 2013	UT Spot	6	0.2260 in	0.2152 in
Dec 18, 2011	UT Grid + RT	6	0.2402 in	0.2340 in
Aug 14, 2009	UT Grid + RT	6	0.2581 in	0.2459 in
Feb 25, 2007	UT Grid + RT	6	0.2814 in	0.2737 in
Jan 1, 2005	UT Grid + RT	6	0.3009 in	0.3000 in
Feb 12, 2003	UT Grid (API 572)	6	0.3168 in	0.3114 in
Feb 5, 2001	UT Spot	6	0.3344 in	0.3159 in