V-1278 — Catalyst Slurry Drum V-1278

Hydrocracker · Catalyst Slurry service · Installed Aug 29, 1996 (30 yrs in service)

High

Current Min. Thickness

0.441 in

t-min 0.578 in

Measured Corrosion Rate

8.81 mpy

ML-predicted: 8.59 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. 1

Joint Efficiency0.85

Design Pressure266 psig

Design Temperature223 °F

Operating Pressure191 psig

Operating Temperature196 °F

Diameter61 in

Nominal Thickness0.706 in

Corrosion Allowance0.0625 in

H2S / Chloride0 / 52 ppm

Flow Velocity10.7 ft/s

Process pH4.15

InsulatedYes

Corrosion & Remaining-Life What-If

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

Operating Temperature196°F

H2S Concentration0 ppm

Chloride Concentration52 ppm

Flow Velocity10.7 ft/s

Process pH4.15

Insulated (CUI potential)

MaterialDamage Mechanism

Live Prediction — What-If Model

8.37 mpy

Predicted corrosion rate under these conditions (-0.44 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 Grid (API 572)	6	0.4429 in	0.4408 in
Dec 4, 2025	UT Grid (API 572)	6	0.4477 in	0.4470 in
May 12, 2024	UT Grid (API 572)	6	0.4624 in	0.4454 in
Jun 17, 2021	UT Grid + RT	6	0.4853 in	0.4679 in
Jul 3, 2019	UT Grid (API 572)	6	0.5049 in	0.4884 in
Aug 22, 2016	UT Spot	6	0.5322 in	0.5322 in
Jul 10, 2014	UT Grid (API 572)	6	0.5477 in	0.5402 in
May 8, 2011	UT Grid + RT	6	0.5779 in	0.5629 in
May 28, 2009	UT Grid + RT	6	0.5907 in	0.5887 in
Aug 25, 2006	UT Spot	6	0.6200 in	0.6000 in
May 12, 2004	UT Grid (API 572)	6	0.6385 in	0.6298 in
Jun 13, 2002	UT Grid (API 572)	6	0.6573 in	0.6403 in
Jan 12, 2001	UT Grid (API 572)	6	0.6640 in	0.6472 in
Mar 5, 1998	UT Grid (API 572)	6	0.6943 in	0.6936 in