nace dhahran section november 30, 2020
TRANSCRIPT
NACE Dhahran Section November 30, 2020
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Good Evening!Phil Low/Kelly Baker/Sujay Math
Zerust Oil & Gas (NTI)
[email protected]@[email protected]
Diversified Applications of Vapor Corrosion
Inhibitor (VCI)
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Agenda 1. What are VCI’s and how do they work. P.Low 2. Soil side corrosion “typical” application scenarios for tanks constructed to
API standards. K.Baker3. Soil side corrosion for tanks without liners or with concrete pads P.Low4. VCI/CP interaction on above ground storage tanks. S.Math5. Preservation and pipeline maintenance. P.Low
- CUI and scab repairs using ZIF. P.Low- Preservation and Mothballed equipment. P.Low
6. Pipeline protection during and after hydrotesting/Pipeline Casings. K.Baker. 7. Q&A
What are VCI’s?And how do they work?
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How do VCIs work?5
Aboveground Storage Tanks
Chair: Alfonso Garcia Rojas – Enbridge
Vice Chair: Tim Whited - MESA
NACE TG543 - Standard for External Corrosion Control
of On-Grade Carbon Steel Storage Tank Bottoms
API 2610 - Design, Construction, Operation, Maintenance, and
Inspection of Terminal and Tank Facilities
12.5 Volatile Corrosion Inhibitors (VCI)
API 651 - Cathodic Protection of Aboveground Petroleum Storage
Tanks
API TR655 - Vapor Corrosion Inhibitors for Storage Tanks
Sand Pad – w/Liner
Sand Pad – w/o Liner
Double Bottom – Sand
Double Bottom - Concrete
Concrete or
Asphalt Pad
Foundation Design
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
0 0.5 1 1.5 2
Meta
l Loss (
Mils
)
Elapsed Time (Years)
Underside Injection - Average Corrosion Rate Data
Tank J CR =1.23 mpy
Tank K CR =0.29 mpy
Tank L CR =0.28 mpy
Field Experience – Sand Pad w/Liner
Field Experience – Sand Pad w/Liner
Field Experience – Double Bottom, Sand
Field Experience – Double Bottom, Sand
How Do We Know VCI Works?14
▸ VCI History – other applications
▸ Coupons
▸ Electrical Resistance Probes
▸ Ultrasonic Thickness Probes
▸ Others
▹ Inhibitor Delivery
▹ Gas Detection
How Do We Know VCI Works?15
Corrosion Rate Data
Coupons UT ProbesER Probes
Tanks W/Out Liner - Chime Ring Delivery System CRD/F
Tanks W/Out Liner - Chime Ring Delivery System CRD/F
Tanks W/Out Liner - Chime Ring Delivery System CRD/F
Target Tanks for CRD/F delivery system:
Tanks without liners
To address critical <3-5 mtrs from annulars
Concrete pads (Chime Flood)
New build Concrete pads
New construction pads without liners
In service option for all tank civil configurations.
The Art of Chime Sealing 20
• Create a physical barrier
• Stops water and any further potential containment
Ingress entering underside of the tank bottom
• Ensures VCI’s are contained within the underside
environment
• Can assist with the protection of blading corrosion
around the annular ring.
• Can be applied up the tank wall to protect the corner
weld - be careful with this approach API Inspection
criteria(s) *
• Can be applied to areas surrounding the hold down
bolts.
• New API Standard will Include Chime Seal
Why do so many Fail? 21
• Adhesives/Glues/Resins/Primers
• Adhesion and to multiple substrates
• Movement/Settlement MAIN !!
• Environmental Issues/Contaminants
• UV
• Mechanical Damage
• Disbondment
• Poor Preparation
• Not Following Manufacturers Implementation
procedure
• Can you create a true factory environment in the field
Personal Preference….22
• Viscoelastic • No reactive groups. Inert and
stable.
• Van Der Waals Forces
• Adheres to almost any substrate
• Viscous in nature
• Cold Flow properties
• Non Ageing
• No Disbondment
• Forgiven in a field environment.
• ST2
Improving CP System Performance for AST Bottoms with VCIs
Sujay Math, Ph.D.
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AST Soil-Side Bottom
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Cathodic Protection and Vapor Corrosion Inhibitors
• Cathodic Protection (CP) systems for tank bottoms • Impressed current anode (large diameter tanks)
• Galvanic anode (small diameter tanks)
• Protection is by polarization of tank bottom in negative direction with respect to native potential: tank bottom cathode
• Vapor Corrosion Inhibitors (VCIs)• Applied as liquid slurry or dry powder, corrosion mitigation is by vapors
• Protection is by chemical action (chemisorption)
• Chemical molecules affect metal/soil interface and retard corrosion rate
• VCI, CP both are effective corrosion control methods
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Cathodic Protection System for ASTs
• Commonly used anodes for CP systems• Mixed-Metal Oxide (MMO) anode for grid system
• MMO anode in coke-breeze sock (Linear anodes) for concentric-ring system
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VCI Delivery Into Sand Base
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CP Anode
Chime Seal Applied
Cathodic Protection and Vapor Corrosion Inhibitors -Standards
NACE
SP0193 : CP Standard
TG 543*: VCIs and Alternative methods Standard
API
API 651 : CP Standard
API 655*: VCI Technical Report
API 2610: Tank Terminals Standard
* New standards
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Electrolyte Resistivity
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VCI Chemistries
Amine-Carboxylate VCIs
• Decreases Resistivity
• Increases pH
API 651: Desired Sand Pad Quality
potable water pH = 7.4
Property Desired Value
Electrical Resistivity
Resistivity
> 10,000 ohm-cm
cm
pH > 8.0
Chloride Levels
Levels
< 10 ppm
Sulfate Levels < 200 ppm
Sulfide Levels < 10 ppm
Electrolyte Resistivity vs. Corrosivity
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Potable Water 3.5% NaCl 5% VCI Potable Water 3.5% NaCl 5% VCI
Day 0 Day 365
Electrolytes Potable Water 3.5% NaCl 5% VCI
Electrical Resistivity, ohm-cm 4400 21 47
Experimental Studies
• Electrical Resistivity of Electrolytes• Potable Water, 3.5% NaCl and 5% VCI
• 4-pin Miller Soil-Box Test
• Weight Loss Coupons (2-inch x 3.5-inch)
• Cathodic Protection Current Distribution• Water Bath Setup (10 ft x 3 ft x 1.3 ft)
• A36 grade steel plate (120-inch x 6-inch x 0.25-inch)
• A36 grade steel coupons (2-inch x 2-inch x 0.25-inch)
• MMO ribbon anode grid system at 5 feet spacing
• DC power supply, constant current mode
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Water bath setup for CP current distribution
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Water bath setup for CP current distribution
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Electrolyte Resistivity
Wenner 4-pin soil resistivity field test method
Simulated Clean Sand:
DI + Potable Water = 24830 ohm-cm
VCI Electrolyte:
2.5 % VCI = 1337 ohm-cm
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Clean Sand 2.5% VCI
Resistivity, ohm-cm 24830 1337
0
5000
10000
15000
20000
25000
30000
Resis
tivity,
ohm
-cm
Anode to Tank Bottom Resistance
• NACE CP-4 Manual: AST CP system design
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ρ = 10,000 to 50,000 ohm-cm (wet to dry)
sand resistivity
Anode Throw and Spacing
• NACE CP-4 Manual: AST CP system design
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Rule of Thumb, L = 3.5 d
Cathodic Protection Current Distribution
• Total surface area of steel plate with coupons = 5.15 ft2
• CP current applied• 5 mA (current density = 1 mA/ft2)
• 10 mA (current density = 2 mA/ft2)
• 40 mA (current density = 8 mA/ft2)
• Current distribution from anode• Single point anode
• Anode grid system (5 ft. c/c)
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Simulated Sand Electrolyte: Single Point Anode
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VCI Electrolyte: Single Point Anode
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Simulated Sand Electrolyte: Anode Grid System
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VCI Electrolyte: Anode Grid System
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Conclusions
1. VCIs lower the electrical resistivity of electrolytes due to their ionic strength. Generally,the lower electrical resistivity is indicative of corrosivity; however, this concept does notapply to VCI electrolytes.
2. The coupon immersion test results showed corrosion on potable water and 3.5% NaClelectrolytes, whereas no corrosion is observed on 5% VCI electrolyte coupon, for 365days of continuous immersion. The electrical resistivity of 3.5% NaCl and 5% VCIelectrolyte was similar.
3. Addition of VCIs to the simulated clean sand electrolyte lowered the resultant electricalresistivity of the electrolyte. This effect aided in lower CP anode ground bed resistanceand resulted in uniform CP current distribution and polarization levels on the tank bottomplate.
4. The current required to achieve NACE recommended 100-mV criteria for effective CP waslower for the VCI electrolyte.
5. Using VCI and CP in combination proves to be an effective corrosion protection strategyfor aboveground storage tank soil-side bottoms resting on sand pads.
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ZIF Tape – CUI/Scab Repairs/Flanges
What is ZIF Tape…
1. ZIF tape is a self fused corrosion inhibiting Tape based on silicone elastomers withproprietary corrosion Inhibitor chemistry impregnated into the matrix.
2. ZIF is cold applied and requires only an ST2.
3. Good mechanical properties/robust due to silicone nature.
4. Only bonds to itself, resulting in a very easy removal and easy inspection process.
5. No residues following removal.
6. Translucent allowing visual inspections.
7. Wind/UV stable.
8. Minimizes entire work parties and entire processes resulting in large costsavings. – Explain Inspections/Maximo processes…
9. Great temperature range -40deg.C to +220deg.C
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Areas…
1. Flanges
2. CUI
3. Scab repairs
4. Coating defects
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Winner of the French Oil & Gas
Council Innovation Award for
Zerust’s® ZIF Tape
Flanges…
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AxxaWash10
AxxaWashNW10 After 3hours( CityWater)
WITH WITHOUT
Flanges…
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CUI+ SCAB Repairs …
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CUI+ SCAB Repairs …
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Testimonial…
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Preservation/Warehousing/Mothballing/Stacking…
1. Static/Rotating
2. Electrical and instrumentation (E&I)
3. Engine and Gear Box
4. Hydraulic
5. Water treatments
6. Coatings – Waxes/RP,s
7. Voids/Hulls/Pontoons
8. Trunnions/Dead Legs.
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Preservation/Warehousing/Mothballing/Stacking…Examples.
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Preservation/Warehousing/Mothballing/Stacking…Examples.
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Rust removal/waxes/greases/RP’s
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Pipeline Protection/Pipe Casings
Cased Crossing (Pipe Casing)
Roads
Railways
Waterways
Pipe Casing – Regulatory Status
SP200-2014
Shorts
New / Sealed
Metallic Short
Electrolytic Short
NACE SP200-2014
Appendix A▹Section A3 Treating the Casing Annulus with Corrosion-Inhibiting Products• A3.1 There are two fundamental options available to
accomplish this method of corrosion mitigation inside casings:
• A3.2 Option 1: Fill the Casing with Corrosion-Inhibiting Gel Filler
• A3.3 Option 2: Leave the Casing Annulus Unfilled and Apply a Multiphase Vapor Corrosion Inhibitor System
Multiphase - Dry
VCI – in vapor space SCI – for water in casing
Multiphase - Slurry
VCI – in vapor space SCI – in slurry for water in casing
Corrosion Inhibiting Gel
VCI – in vapor space SCI – in gel for water in casing
Pipelines
VCI Slurry Injection – Non-Piggable66
Gravity Feed VCI
• Treats residual water
along the way
• Volatizes along the
way
• Settles in low points,
treats residual water
Low areas accumulate hydrotest residual water
VCI Slurry Injection – Non-Piggable67
VCI Slurry Injection - Piggable68
VCI Slurry Injection - Piggable69
• Design and materials help mitigate corrosion
• Cathodic Protection is effective in mitigating corrosion
• Standards and Regulations are looking at new tools to combat
corrosion
• Vapor Corrosion Inhibitors are one of those tools
• Field experience indicates that VCIs are effective
Summary
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THANK YOU! Any questions?END OF SESSION.
Osama Dalank (Sogec): Philip Low (Zerust): [email protected] [email protected]