© 2013 Chevron U.S.A., Inc. All rights reserved.
Metallurgy and Corrosion Modeling, Materials, and Monitoring
for Process Safety Management
Ned Niccolls
Senior Consulting Materials Engineer
Chevron Energy Technology Company
August, 2013
Richmond, CA
AIChE/SAChE Faculty Workshop on PSM
© 2013 Chevron U.S.A., Inc. All rights reserved.
Metallurgy and Corrosion
Outline
Overview
PSM Context
Challenges and Realities
Example: “Deep Dive” of Wet H2S Cracking
Some Advanced Technologies and Opportunities
Appendix: Chevron Investigation Report for the August 6, 2012 fire
(more details available from the Chevron.com web site)
2
© 2013 Chevron U.S.A., Inc. All rights reserved.
Overview: Modeling, Materials, and Monitoring to
Prevent Corrosion
3
Corrosion Prediction/Modeling
Inspection/
Monitoring
Materials
© 2013 Chevron U.S.A., Inc. All rights reserved.
PSM Context
Greatest impact on safety and reliability was the serious adoption of
The Tenets of Operation.
4
The Tenets of Operation are based on two key principles:
"Do it safely or not at all" "There is always time to do it right"
Always...
1. Operate within design and environmental limits.
2. Operate in a safe and controlled condition.
3. Ensure safety devices are in place and functioning.
4. Follow safe work practices and procedures.
5. Meet or exceed customers’ requirements.
6. Maintain integrity of dedicated systems.
7. Comply with all applicable rules and regulations.
8. Address abnormal conditions.
9. Follow written procedures for high-risk or unusual situations.
10. Involve the right people in decisions that affect procedures and equipment.
© 2013 Chevron U.S.A., Inc. All rights reserved.
Challenges and Realities
5
© 2013 Chevron U.S.A., Inc. All rights reserved.
Typical Crude Distillation Seems pretty simple, but…..
6
© 2013 Chevron U.S.A., Inc. All rights reserved.
Typical Crude Unit Overhead Large hardware, some not easily accessible…..
7
© 2013 Chevron U.S.A., Inc. All rights reserved.
Typical Crude Distillation Unit Showing potential metallurgical damage mechanisms
8
Atmospheric
Column Vacuum
Column
Flash
Drum
Furnace Wastewater
Desalter
Preheaters
Crude
Feed
Brine
Corrosion Caustic Cracking
and Corrosion
Hot H2S
Corrosion
Graphitization
Naphthenic
Acid Corrosion
Creep
Creep
Nap. Acid
Hot H2S
Corrosion
Polythionic
Acid SCC
Polythionic
Acid SCC
Under Deposit
Corrosion
HCl/Chloride
Salt Corrosion
HCl/Chloride
Salt Corrosion Amine SCC
Wet H2S
“Low” Temp. Organic Acid
Corrosion
In the LER
• Brittle Fracture
• CUI
© 2013 Chevron U.S.A., Inc. All rights reserved.
“Deeper Dive” Discussion:
Wet H2S (Hydrogen) Effects on Steels
PR
950625-3
9
Quiz:
Where has hydrogen and steel been in the
news recently?
© 2013 Chevron U.S.A., Inc. All rights reserved.
© 2013, The San Francisco Chronicle. All rights reserved. Used by permission.
Bay Bridge Bolt Failure
10
© 2013 Chevron U.S.A., Inc. All rights reserved.
Bay Bridge Bolt Failure
11
© 2013, San Jose Mercury News. All rights reserved. Used by permission.
© 2013 Chevron U.S.A., Inc. All rights reserved.
“Deeper Dive” Discussion:
Wet H2S Effects on Steels
PR
950625-3
12
© 2013 Chevron U.S.A., Inc. All rights reserved.
SSC + HIC Damage
HIC Damage
G010570.jpg, G
010571.jpg
Wet H2S effects
13
© 2013 Chevron U.S.A., Inc. All rights reserved.
Formation of Hydrogen Blisters by H2S Corrosion
G9901105
A clean steel surface normally catalyzes the combination of atomic hydrogen formed by corrosion to molecular hydrogen, but if H2S is the corrodant, the combination at the metal surface is greatly retarded and atomic hydrogen diffuses into the steel.
The buildup of an iron sulfide layer at the metal surface slows the rate of corrosion, and even if the steel has an internal defect, blistering may not occur. However, if cyanides are present along with the H2S, the ferrous sulfide layer may be dissolved, and hydrogen diffusion continues, creating high internal pressures at the defect, and as the steel eventually yields, producing blisters.
H0 + H0 + H2 (At Defect)
With FeS layer, reaction slows and blistering may not occur.
With cyanides present, FeS scale dissolves:
FeS + 6CN- Fe (CN)6 + S=
and corrosion continues, with formation of hydrogen blisters.
= =
14
© 2013 Chevron U.S.A., Inc. All rights reserved.
Effect of Changing Process Conditions on the Likelihood
for Wet H2S Cracking
New Vessel Process Upset
Crack Growth
Protective Scale
Hyd
rog
en
Flu
x In
to S
tee
l
Crack Initiation
and Growth
Source: NACE Corrosion 1998, Paper 394
Time
G9900115
15
© 2013 Chevron U.S.A., Inc. All rights reserved.
Advanced Technology Opportunities
Corrosion Prediction/Modeling
Materials
Inspection/Monitoring
16
© 2013 Chevron U.S.A., Inc. All rights reserved.
Corrosion Prediction/Modeling Flow regimes, surface conditions, kinetics, model verification….
17
© 2013 Chevron U.S.A., Inc. All rights reserved.
Materials Surface engineered materials, advanced nonmetallics/composites, alloys
18
© 2013 Chevron U.S.A., Inc. All rights reserved.
Corrosion Monitoring and Inspection
A number of technologies:
advanced corrosion probes
that penetrate into the
process….permanently
mounted external thickness
monitors… increasingly
wireless enabled….data
integration opportunities....
seeking capability for
“complete” inspection and
monitoring capability through
insulation
19
© 2013 Chevron U.S.A., Inc. All rights reserved.
Opportunities
Collaboration of Academia, Government Laboratories, and Industry
– Example: Corrosion Under Insulation inspection work, and atomistic
corrosion modeling with Los Alamos
Tremendous opportunities within the Energy Sector
– For both “Traditional” and Alternative Energy spaces
20
© 2013 Chevron U.S.A., Inc. All rights reserved.
Appendix:
Chevron Investigation Report for the August 6, 2012 Fire
21
© 2013 Chevron U.S.A., Inc. All rights reserved.
Source: Richmond Refinery 4 Crude Unit Incident, August 6, 2012
(Report prepared by the CUSA Richmond Investigation Team, April 12, 2013)
22
© 2013 Chevron U.S.A., Inc. All rights reserved.
Source: Richmond Refinery 4 Crude Unit Incident, August 6, 2012
(Report prepared by the CUSA Richmond Investigation Team, April 12, 2013)
23
© 2013 Chevron U.S.A., Inc. All rights reserved.
Source: Richmond Refinery 4 Crude Unit Incident, August 6, 2012
(Report prepared by the CUSA Richmond Investigation Team, April 12, 2013)
24
© 2013 Chevron U.S.A., Inc. All rights reserved.
Source: Richmond Refinery 4 Crude Unit Incident, August 6, 2012
(Report prepared by the CUSA Richmond Investigation Team, April 12, 2013)
25
© 2013 Chevron U.S.A., Inc. All rights reserved.
Source: Richmond Refinery 4 Crude Unit Incident, August 6, 2012
(Report prepared by the CUSA Richmond Investigation Team, April 12, 2013)
26
© 2013 Chevron U.S.A., Inc. All rights reserved.
Source: Richmond Refinery 4 Crude Unit Incident, August 6, 2012
(Report prepared by the CUSA Richmond Investigation Team, April 12, 2013)
27
