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How VCI’s Can Reduce Corrosion forUST System Components
Presented by David Durling, Zerust Oil & GasEfim Lyublinski, Monique Posner, Terry Natale,
Yefim Vaks, Ronnie Singh, Kelly Baker, Gautam RamdasNorthern Technologies International Corporation, USA
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Marcelo SchultzPetrobras, Brazil
Marshall Mott-SmithMott-Smith Consulting
AGENDA
• What are VCIs
• Who NTIC is
• Industry Applications– Mothballing/Storage
– AST Floors
– AST Roofs
– Pipeline Casings
– UST Sumps
• Intro to Ethanol Corrosion
• Questions2
3
Definition - VCI
Also referred to as Volatile Corrosion Inhibitors
• A class of corrosion inhibiting compounds which have vapor pressures higher than that of air.
• This results in the release of vapor molecules of inhibitor into the air.
Vapor Corrosion Inhibitors
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Definition – Con't
VCIs can be engineered to address specific issues causing CorrosionDifferent Mechanisms for Different Purposes
Passivatorso Anodic inhibitors that shift the metal potential in the positive direction helping the
metal form its own passivation layer
Barrierso Act as a barrier layer between the metal and the environment, adsorption can be
either physical (electrostatic) or chemical (sharing electrons)
Scavengerso Eliminate dissolved oxygen from a closed system (neutral or alkaline pH) (sulfite)o Inhibitor reacts with acidic gases in air space (ReCast-R1)
Neutralizero Reduces the concentration of H+ ions in solution
Definition Con’t
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VCI molecules fill space and
deposit on all surfaces.
• Can work for immersed surfaces
• Not a ‘coating’
• Does not change the metallurgy
• Not permanent
• Can be painted/welded
• Non-toxic
• Can be designed for the service
exposure
Many forms of VCI
1. Self-fogging Flash Corrosion Inhibitor (FCITM) technology
– High vapor pressure, low vapor density
– Fast acting
– Fills vapor spaces immediately
– Highest volume of protection per weight of active ingredient
– Navigates complex systems
2. Long-term Vapor Corrosion Inhibitor (VCI) protection
– Slower evolving, long-term vapor corrosion inhibitor
3. Long-term Soluble Corrosion Inhibitor (SCI) protection
– Contact corrosion inhibitors activated when water present
– Chloride “neutralizer”
What’s the difference?
Not “NEW” Technology
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Clean, environmentally friendly
Requires no cleaning prior to assembly
VCIs have been sold through major retailers for years
Several ‘consumer market’ products you can try
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• Lowes
• Cabellas
•Flambeau
•Kobalt
•…others
Some consumers are more demanding than others …
US Navy SEALS
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VCI capsules in the engine housing
US Marines in Iraq
VCI gun sleeves
NACE Corrosion Innovation AwardsSalt Lake City - 2012
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Flange
Savers™
ReCAST
- Roof
Managing Corrosion
Corrosion cannot be eliminated, it’s mechanism
can only be slowed
Applications!
How are VCIs currently being used
in Oil & Gas?
Low Temperature Flanges.
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• Proprietary dual layer plastic film
• Impregnated with a VCI to enclose flanges, bolts and weld joints
• Average 2+ year life.
Long Term Corrosion Protection
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Vapor CapsulesNumerous applications
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Protection of Electrical & Electronic Control Panels and Safety Switch Boxes
Applications!
Tank Floors!Underside
Floor ConfigurationsNew/Existing – In Service/Out of Service
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Tank Soil Side Bottom Protection Matrix
Cathodic Protection VCI/SCI Liquid VCI Powder VCI Suggested VCI / SCI System
Sand Base w/ Liner Yes Yes Yes Yes
- Ring-Wall Injection System - Dry Underside Tube System - Internal Flood System - Dry External Ring System - Wet External Ring System
Sand Base w/o Liner Yes Dry System Only No Yes- Dry Underside Tube System - Dry External Ring System
Concrete/Asphalt No Yes Yes Yes- Dry External Ring System - Wet External Ring
Double Bottom w/LinerEffectiveness
determined by sand depth
Yes Yes Yes- Ring-Wall Injection System - Dry Underside Tube System - Internal Flood System
Double-Bottom w/o LinerEffectiveness
determined by sand depth
If original floor has no penetrations (?)
If original floor has no penetrations (?)
Yes- Dry Underside Tube System - Ring-Wall Injection System? - Internal Flood System?
Chloride Contaminated Sand Base w/ Liner
Yes Yes Yes No - Chloride Remediation System
State of Florida
“ReCAST-SSB System provides environmental protection substantially equivalent to that provided by compliance with the requirements established in Rules 62-762.501(1)(f)4., 62-762.701(1)(b), F.A.C and may be used as a Cathodic protection system… Pursuant to Rule 62-762-851(2), F.A.C. … is approved in the State of Florida as a corrosion inhibitor system that is applied to the soil filled area between the secondary containment system of an aboveground storage tank.” 21
Tank
Shell
Sand Base
Tank Floor
& Void
Gap
VCI Molecules
VCI Adsorb
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VCI Effect Under Tank Floors
CONCRETE or ASPHALT PAD
INHIBITOR TUBE REFILL PORTS
PERFORATED INHIBITOR TUBE
CHIME / TUBE SEAL
External Ring System
Zerust™ Confidential 2014
RING WALL
BERM AREA
MONITORING PORT
INHIBITOR STRIPS
INHIBITOR POWDER
SSB New Floor Powder System
SAND BASE
TANK FLOOR
Parallel Tubes
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Applications!
Tank Roofs!
Cone roof supports!Continuity of coatings?
Coatings do not effectively
cover all surfaces
Tank roof and support beam
H2O
H2SSO2
H2SO4
O2
Examples of AST Roof corrosion
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Internal acid gas vapors cause underside corrosion
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Mitigate roof underside corrosion
Molecular vapor pressure disperses the inhibitor from cannisters installed during a tank shutdown.
Inhibitor levels can be monitored and replenished while the tank is “In-Service”.
New dispenser design.
Test dispenser
design.
The delivery system!
Mono-Molecular Barrier
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VCI takes preference on steel surface
Applications!
Pipe Casings!
Pipe CasingsLong Term Corrosion Protection
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Surface structurei.e.: road, rail, etc.
Vent Pipe
Casing Seal
Applications!
UST Sump Pit!
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UST System Components
UST Sump
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UST Vapor Space Chemistry
+
=
Ethanol Vapors
Water
Acetic Acid+
Bacteria
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February 20, 2014
December 5, 2013
No Inhibitor
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Current Test Locations in TexasSite 1, September 2014
UST Test Sump
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Current Test Locations in TexasSite 1 After 5 weeks no Inhibitor
UST Test Sump
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Test site 2, October 2014(this store is around 3 yrs old!)
UST Test Sump
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Test site 2(this store is around 3 years old)Coupons After 6 Weeks!
UST Test Sump
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Test site 3, Jan 2015
UST Test Sump
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3rd site in Texas Coupon after 6 weeks!
Test Coupon
UST Test Sump
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UST Lab Test
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UST Lab Test
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UST Trial Components
Sample Sump
VCI Volatizes in Enclosure Packet of VCI
Coupon Florida (e10)
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UST Control Sump
Coupon Only
December 5, 2013 January 16, 2014
Some Visible Surface Corrosion
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UST Control Sump
Coupon Only
December 5, 2013 January 16, 2014
Significant Surface Corrosion
Beta Test
Annual Application
Monthly Application
• Relatively Clean Surface & Tightened Fittings
Site 1After 6 weeks with Inhibitor
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UST Test Sump
Site 2After 6 weeks with Inhibitor
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UST Test Sump
Site 3After 6 weeks with Inhibitor
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UST Test Sump
UST Sump - Conclusions
1. Acetic Acid can form in the sumps, due to
Ethanol vapors, bacteria and moisture.
2. Absence of any of the three seems to result in
a much lower corrosion rate.
3. Vapor Corrosion Inhibitors can reduce
corrosion rates.
4. Sump condition is a factor in the effectiveness
of the VCI.
5. Testing is expanding into long term trials.57
