V-1074 — Coker Vapor Drum V-1074

Alkylation Unit · Coker Vapor service · Installed Sep 1, 1985 (41 yrs in service)

High

Current Min. Thickness

0.161 in

t-min 0.347 in

Measured Corrosion Rate

7.08 mpy

ML-predicted: 7.32 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-387-11 Cl.2 (1.25Cr-0.5Mo)

Design CodeASME BPVC Section VIII, Div. 2

Joint Efficiency1.00

Design Pressure195 psig

Design Temperature615 °F

Operating Pressure166 psig

Operating Temperature581 °F

Diameter63 in

Nominal Thickness0.476 in

Corrosion Allowance0.0625 in

H2S / Chloride18 / 7 ppm

Flow Velocity2.3 ft/s

Process pH7.43

InsulatedNo

Corrosion & Remaining-Life What-If

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

Operating Temperature581°F

H2S Concentration18 ppm

Chloride Concentration7 ppm

Flow Velocity2.3 ft/s

Process pH7.43

Insulated (CUI potential)

MaterialDamage Mechanism

Live Prediction — What-If Model

6.73 mpy

Predicted corrosion rate under these conditions (-0.35 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 — Erosion-Corrosion

API 571 §4.2.13

Mechanical removal of protective scale by high-velocity flow or entrained solids, accelerating the underlying corrosion mechanism.

Recommended inspection approach: UT thickness at flow-direction changes (elbows, reducers); review process velocity against API RP 14E erosional velocity limits.

Inspection History

UT thickness readings, most recent first

Date	Method	CML Count	Avg Thickness	Min CML Thickness
Aug 22, 2026	UT Spot	6	0.1737 in	0.1614 in
Mar 12, 2025	UT Grid + RT	6	0.1737 in	0.1564 in
Apr 12, 2023	UT Spot	6	0.1737 in	0.1562 in
Aug 29, 2021	UT Grid + RT	6	0.1737 in	0.1572 in
Dec 14, 2018	UT Grid + RT	6	0.1737 in	0.1567 in
Sep 30, 2015	UT Spot	6	0.1737 in	0.1604 in
Mar 10, 2014	UT Grid (API 572)	6	0.1737 in	0.1657 in
Sep 3, 2012	UT Grid + RT	6	0.1737 in	0.1688 in
Dec 31, 2009	UT Grid + RT	6	0.1737 in	0.1566 in
Dec 13, 2006	UT Grid + RT	6	0.1737 in	0.1684 in
May 5, 2005	UT Grid (API 572)	6	0.1912 in	0.1864 in
Dec 1, 2003	UT Grid + RT	6	0.2141 in	0.2010 in
May 18, 2002	UT Spot	6	0.2357 in	0.2242 in
Nov 27, 1999	UT Grid (API 572)	6	0.2695 in	0.2652 in
May 25, 1998	UT Spot	6	0.2914 in	0.2869 in
Oct 23, 1996	UT Grid + RT	6	0.3137 in	0.3112 in
Apr 14, 1995	UT Grid + RT	6	0.3386 in	0.3230 in
Jul 2, 1993	UT Grid (API 572)	6	0.3652 in	0.3539 in
Dec 11, 1990	UT Spot	6	0.3986 in	0.3953 in
Sep 6, 1987	UT Grid + RT	6	0.4447 in	0.4441 in