M AT E R I A L S S E L E C T I O N & D E S I G N
preparation tools or specialized hydro grit
blasting equipment can be used to remove the surface corrosion.
Novalac-based epoxies are highly
chemical resistant and bond well to metals. The plant owner or maintenance
manager may call for chemical compatibility testing of these polymers to confrm
that the FRP repair is compatible with
the fuid in the pipe.
FRP repairs also serve as a barrier to
prevent additional CUI once the repair
is in place. These specialized epoxy polymers are formulated to have a high operating temperature limit, and in some
applications, the high operational temperatures may actually serve to post-cure
the repair, which tends to make the FRP
even stronger.
For detailed design factors, the reader
should consult the ASME standard.3
References
Conclusions
http://www.mercurynews.com/business/
ci_21734849/chevron-says-crude-unitknocked-out-by-richmond. March 15,
2013.
This article has discussed how CUI
manifests itself in a variety of specifc
chemical attacks. Keeping the pipe dry
and protected is necessary to maintain
pipe integrity. In the event that some wall
loss occurs, one means of repair that does
not require a plant shutdown is an FRP
wrap. These wraps serve to restore lost
structural integrity while mitigating external corrosion at elevated temperatures,
thereby preventing additional wall loss
associated with CUI.
Also discussed were FRP design recommendations. The chemical and thermal compatibility of the repair solution
should be closely examined and compared to working fuids and plant operating conditions. Finally, trained, experienced, certifed, and reputable teams
should be selected to ensure proper
installation.
NACE International, Vol. 52, No. 5
1 U.S. Code of Federal Regulations (CFR)
Title 29, "Occupational Safety and
Health Standards," Part 1910, "Personal
Protective Equipment," Standard
1910.134 (Washington, DC: Offce of
Federal Register).
2 Clean Water Act (Washington, DC:
EPA, 1972).
3 ASME PCC-2—2011, "Repair of
Pressure Equipment and Piping," Part 4,
"Nonmetallic and Bonded Repairs"
(New York, NY: ASME, 2011.)
Bibliography
American Society of Mechanical Engineers,
www.asme.org.
American Society for Nondestructive Testing, www.asnt.org.
Avalos, G. "Chevron says crude unit
knocked out by Richmond refnery fre
will be offine for rest of 2012." Contra
Costa Times, October 9, 2012.
Jones, D., Principles and Prevention of Corrosion,
2nd Ed. Upper Saddle River, NJ:
Prentice Hall, Inc., 1996.
NACE International, www.nace.org.
NRI., www.NeptuneResearch.com.
The National Board of Boiler and Pressure
Vessel Inspectors www.nationalboard.
org.
LARRY DEATON is the vice president of engineering
at NRI, 1346 S. Killian Dr., Lake Park, FL 33403,
e-mail: ldeaton@neptuneresearch.com. He has
been a practicing engineer for 25 years with the
U.S. Navy, Ford Motor Co., Lockheed Martin, and
NRI, specializing in fuid fows, fanged joints, and
piping repairs. He has an M.S. degree in mechanical
engineering from San Diego State University, a
Ph.D. in engineering mechanics from Michigan
Tech, and is a registered Professional Engineer.
A member of NACE International, Deaton is the
co-author of Repair of Pipelines using Fiber
Reinforced Polymers (Woodhead Publishing).
May 2013 MATERIALS PERFORMANCE
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