V-1214 — Hydrotreater Feed Drum V-1214

Alkylation Unit · Hydrotreater Feed service · Installed Sep 1, 1984 (42 yrs in service)

Critical

Current Min. Thickness

0.079 in

t-min 0.167 in

Measured Corrosion Rate

4.91 mpy

ML-predicted: 5.82 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-240-316L Stainless

Design CodeASME BPVC Section VIII, Div. 1

Joint Efficiency0.85

Design Pressure131 psig

Design Temperature566 °F

Operating Pressure92 psig

Operating Temperature473 °F

Diameter36 in

Nominal Thickness0.328 in

Corrosion Allowance0.0938 in

H2S / Chloride6 / 294 ppm

Flow Velocity16.8 ft/s

Process pH7.49

InsulatedNo

Corrosion & Remaining-Life What-If

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

Operating Temperature473°F

H2S Concentration6 ppm

Chloride Concentration294 ppm

Flow Velocity16.8 ft/s

Process pH7.49

Insulated (CUI potential)

MaterialDamage Mechanism

Live Prediction — What-If Model

8.68 mpy

Predicted corrosion rate under these conditions (+3.77 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 Grid (API 572)	6	0.0835 in	0.0794 in
Dec 17, 2024	UT Spot	6	0.0835 in	0.0681 in
Jun 11, 2023	UT Grid + RT	6	0.0835 in	0.0829 in
Oct 19, 2021	UT Spot	6	0.0835 in	0.0818 in
May 17, 2019	UT Spot	6	0.0835 in	0.0741 in
Dec 2, 2016	UT Spot	6	0.0835 in	0.0751 in
Oct 27, 2013	UT Spot	6	0.0835 in	0.0651 in
Nov 23, 2011	UT Grid (API 572)	6	0.0835 in	0.0667 in
Apr 27, 2009	UT Grid + RT	6	0.0835 in	0.0806 in
Oct 18, 2007	UT Spot	6	0.0835 in	0.0770 in
Aug 5, 2005	UT Spot	6	0.0835 in	0.0738 in
Feb 22, 2003	UT Grid (API 572)	6	0.0835 in	0.0820 in
Jan 2, 2000	UT Grid (API 572)	6	0.0835 in	0.0737 in
Apr 26, 1997	UT Spot	6	0.1084 in	0.0971 in
Jan 22, 1995	UT Grid (API 572)	6	0.1493 in	0.1346 in
Jan 4, 1992	UT Grid (API 572)	6	0.2012 in	0.1974 in
May 17, 1990	UT Spot	6	0.2284 in	0.2169 in
Nov 20, 1987	UT Spot	6	0.2738 in	0.2657 in
Apr 11, 1986	UT Spot	6	0.3001 in	0.2946 in