CP Presentation (compressed).ppt

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The presentation is to present how a basic Cathodic Protection The presentation is to present how a basic Cathodic Protection

System functions to protect steel structures. The idea of Cathodic System functions to protect steel structures. The idea of Cathodic

Protection (CP) System is to prevent and mitigate the corrosion Protection (CP) System is to prevent and mitigate the corrosion

activities occur at structures by using materials called anodes. Anodes activities occur at structures by using materials called anodes. Anodes

material will be discussed at the slide later and some other applications material will be discussed at the slide later and some other applications

of it. of it.

By the end of the slide, reader should have basic idea of how CP By the end of the slide, reader should have basic idea of how CP

System protect a structure.System protect a structure.

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In order for a structure to corrode, three conditions must be present.In order for a structure to corrode, three conditions must be present.1.1. Two dissimilar metalsTwo dissimilar metals2.2. Electrolyte (water, moisture, liquid and such)Electrolyte (water, moisture, liquid and such)3.3. Conducting path between the dissimilar metals. Conducting path between the dissimilar metals.

Chronology for corrosion protection usually are:Chronology for corrosion protection usually are:1. Coating System : a. Paint coating1. Coating System : a. Paint coating b. Physical protection eg. SEASHIELDb. Physical protection eg. SEASHIELD

2. Cathodic Protection: 2. Cathodic Protection: Cathodic Protection (CP) System is a proven method to reduce or Cathodic Protection (CP) System is a proven method to reduce or

prevent prevent corrosion rate on metal structures.corrosion rate on metal structures. Two types of CP System: Two types of CP System: Galvanic CP System & Impressed Current Galvanic CP System & Impressed Current Cathodic Protection (ICCP) System. Cathodic Protection (ICCP) System.

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Coating is usually the main protection for the offshore structures before Coating is usually the main protection for the offshore structures before

SEASHIELD and/or CP System are implemented. SEASHIELD and/or CP System are implemented.

The common coating for offshore structure is Coal Tar Epoxy (CTE).The common coating for offshore structure is Coal Tar Epoxy (CTE).

CTE Coating is a polyamide/epoxy coal tar coating formulated to provide CTE Coating is a polyamide/epoxy coal tar coating formulated to provide

excellent resistance to crude oil, fuel oil, chemicals, corrosion and excellent resistance to crude oil, fuel oil, chemicals, corrosion and

seawater. seawater.

CTE is widely used Dam gates, lining for petroleum storage tanks, water CTE is widely used Dam gates, lining for petroleum storage tanks, water

tanks, sewage water treatment tank, marine applications, and heavy tanks, sewage water treatment tank, marine applications, and heavy

duty structural pipe coating. duty structural pipe coating.

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Advantages for CTE:Advantages for CTE:

Excellent protection for submerged and underground structures.Excellent protection for submerged and underground structures.

Economical – the cheapest yet effective protective coating.Economical – the cheapest yet effective protective coating.

Excellent chemical resistance – excellent resistance to both acidic Excellent chemical resistance – excellent resistance to both acidic

and and

alkaline substances.alkaline substances.

Excellent abrasion resistance.Excellent abrasion resistance.

Easy application – simple mixing and application procedures.Easy application – simple mixing and application procedures.

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Fusion Bonded Epoxy (FBE), it is a one-part, heat cured, thermosetting Fusion Bonded Epoxy (FBE), it is a one-part, heat cured, thermosetting

epoxy coating that provides excellent protection for steel piles and epoxy coating that provides excellent protection for steel piles and

could be used for onshore and offshore application.could be used for onshore and offshore application.

FBE can be applied as dual layer product which provides tough physical FBE can be applied as dual layer product which provides tough physical

properties that minimize damage during handling, transportation, properties that minimize damage during handling, transportation,

installation and operation. installation and operation.

FBE has also been designed for good chemical resistance under most FBE has also been designed for good chemical resistance under most

soil condition, seawater environment and wastewater applications.soil condition, seawater environment and wastewater applications.

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Advantages for FBE:Advantages for FBE:

Applied in an automated one-part process so that the mixing, surface Applied in an automated one-part process so that the mixing, surface

preparation, and multiple-coat problems associated with liquid paints preparation, and multiple-coat problems associated with liquid paints

are are

eliminated.eliminated.

Smooth coating, even coating thickness with no runs, sags, or thin Smooth coating, even coating thickness with no runs, sags, or thin

spots spots

common with applying liquid paints.common with applying liquid paints.

Durable and provide twice the impact strength of liquid epoxies. Durable and provide twice the impact strength of liquid epoxies.

The surface provides high abrasion resistance for steel piles.The surface provides high abrasion resistance for steel piles.

Long-term performance in water and sewage environments including Long-term performance in water and sewage environments including

seawater, slurries, methane and hydrogen sulfide exposure. seawater, slurries, methane and hydrogen sulfide exposure.

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SEASHIELD is an physical protection for the steel piles and it is designed SEASHIELD is an physical protection for the steel piles and it is designed to withstand rough and turbulent water condition caused by strong tidal to withstand rough and turbulent water condition caused by strong tidal flows and wave action. It seals the substrate against oxygen and water, flows and wave action. It seals the substrate against oxygen and water, preventing corrosion and deterioration. SEASHIELD 2000 is the common preventing corrosion and deterioration. SEASHIELD 2000 is the common series used in the severe seawater environment. series used in the severe seawater environment.

Advantages:Advantages: Minimal surface preparation.Minimal surface preparation. Immediate protection from further corrosion.Immediate protection from further corrosion. No curing or drying time.No curing or drying time. Hoop tension generated by tightening the nuts and bolts guarantees Hoop tension generated by tightening the nuts and bolts guarantees

the the

water tight seal of paste and tape against the pile.water tight seal of paste and tape against the pile. The jackets are easily installed with adjustable wrenches.The jackets are easily installed with adjustable wrenches.

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There are basically four components of SEASHIELD System:There are basically four components of SEASHIELD System:

1.1. Denso S105 PasteDenso S105 Paste Soft beige paste which may be applied underwater by gloved hand, stiff Soft beige paste which may be applied underwater by gloved hand, stiff

bristle brush or roller on badly corroded and pitted steel above and below bristle brush or roller on badly corroded and pitted steel above and below

water prior to the application of the tape. It displaces water and fills pits and water prior to the application of the tape. It displaces water and fills pits and

depressions. depressions.

2.2. Denso Marine Piling TapeDenso Marine Piling Tape A petrolatum tape formulated for application underwater or to wet surfaces. A petrolatum tape formulated for application underwater or to wet surfaces.

When applied spirally with sufficient tension it will displace water and develop When applied spirally with sufficient tension it will displace water and develop

a water resistant bond to metal surfaces. (150mm or 300mm x 10m rolls)a water resistant bond to metal surfaces. (150mm or 300mm x 10m rolls)

3.3. Outer-cover JacketOuter-cover Jacket A tough ultra-violet resistant HDPE jacket that provides protection to the tape A tough ultra-violet resistant HDPE jacket that provides protection to the tape

against abrasion, wave action and accidental impact.against abrasion, wave action and accidental impact.

4.4. FasteningsFastenings An ultra-violet and salt water resistant acetal polymer smart banding that An ultra-violet and salt water resistant acetal polymer smart banding that

tighten and hold the HDPE jacket .tighten and hold the HDPE jacket .

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1.1. Remove from the area to be protected all marine growth, loosely Remove from the area to be protected all marine growth, loosely adhering coating, and corrosion products (rust) from all exposed adhering coating, and corrosion products (rust) from all exposed metal surfaces by using high pressure water jetting. (additional of metal surfaces by using high pressure water jetting. (additional of CHLOR*RID chemical to accelerate the removal of marine growth.)CHLOR*RID chemical to accelerate the removal of marine growth.)

2. Surface pre-treatment with Denso Paste S105. Denso Paste is 2. Surface pre-treatment with Denso Paste S105. Denso Paste is applied to the areas of deep pitting or weld scars.applied to the areas of deep pitting or weld scars.

3. Tape Wrapping. Denso Marine Piling Tape is used to wrap the pile 3. Tape Wrapping. Denso Marine Piling Tape is used to wrap the pile after Denso Paste S105 is applied. Wrap around the pile following a after Denso Paste S105 is applied. Wrap around the pile following a spiral path until and overlap of 55% is achieved. spiral path until and overlap of 55% is achieved.

4. Install the HDPE Jacket and tighten by polymer smart banding. 4. Install the HDPE Jacket and tighten by polymer smart banding.

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CHLO*RID as an additional chemical CHLO*RID as an additional chemical used to remove marine growth. used to remove marine growth.

Steel pile surface should be cleaned and free Steel pile surface should be cleaned and free from barnacles or marine growth.from barnacles or marine growth.

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High pressure water jetting is High pressure water jetting is sometimes used with CHLO*RID sometimes used with CHLO*RID solution to accelerate removal of solution to accelerate removal of barnacles. barnacles.

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Next step is to apply Denso Paste S105 Next step is to apply Denso Paste S105 as pre-treatment to fill the cavities, as pre-treatment to fill the cavities, voids, pitting and displace water in voids, pitting and displace water in pitting.pitting.

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Followed by wrapping Denso Marine Piling Tape Followed by wrapping Denso Marine Piling Tape to the entire areas where HDPE Jacket protect. It to the entire areas where HDPE Jacket protect. It also acts as the first layer of protection before also acts as the first layer of protection before jacket is installed. jacket is installed.

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After Denso Tape had applied, HDPE Jacket is wrapped to the pile. Then is After Denso Tape had applied, HDPE Jacket is wrapped to the pile. Then is tighten with polymer smart banding system.tighten with polymer smart banding system.

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Figures show a complete HDPE Jacket protected pile with smart banding system.Figures show a complete HDPE Jacket protected pile with smart banding system.

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Galvanic CP System also known as the Sacrificial Anodes CP System. Galvanic CP System also known as the Sacrificial Anodes CP System. Anodes will be depleted and consumed by the protected structure after Anodes will be depleted and consumed by the protected structure after periods of time. periods of time.

Metals usually used as sacrificial anodes are:Metals usually used as sacrificial anodes are: AluminumAluminum ZincZinc Magnesium Magnesium

Aluminum and Zinc anodes are widely used in seawater environment Aluminum and Zinc anodes are widely used in seawater environment whereas magnesium anodes can be used for underground or fresh whereas magnesium anodes can be used for underground or fresh water. water.

Galvanic CP System is commonly used on structures which require small Galvanic CP System is commonly used on structures which require small cathodic protection current and where resistance is low. cathodic protection current and where resistance is low.

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Advantages:Advantages: Self-powered. No external power source is required.Self-powered. No external power source is required. Easy installation.Easy installation. Low maintenance.Low maintenance. Less likely to generate stray current interference on other structures.Less likely to generate stray current interference on other structures. It’s more economical than ICCP if the current requirement is small. It’s more economical than ICCP if the current requirement is small.

Disadvantages:Disadvantages: Low driving voltage.Low driving voltage. Limited application in low resistivity soils.Limited application in low resistivity soils. Not an economical method for large amounts of CP current Not an economical method for large amounts of CP current requirement. requirement. Limited capacity to control stray current effects on the protected Limited capacity to control stray current effects on the protected structure. structure.

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Sacrificial aluminum anodes are installed at the Sacrificial aluminum anodes are installed at the sheet pile for submerged section.sheet pile for submerged section.

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Figures shown are the Aluminum sacrificial Figures shown are the Aluminum sacrificial anodes installed to protect the steel piles.anodes installed to protect the steel piles.

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Figures shown are the Magnesium anodes in a form of Peggy bag.Figures shown are the Magnesium anodes in a form of Peggy bag.

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ICCP System is usually used to protect large bare and coated structures ICCP System is usually used to protect large bare and coated structures in high resistivity electrolytes. ICCP System applies DC current for the in high resistivity electrolytes. ICCP System applies DC current for the anodes but in not Galvanic System. Thus, ICCP System has an extra anodes but in not Galvanic System. Thus, ICCP System has an extra component to supply current to anodes called TRU, Transformer component to supply current to anodes called TRU, Transformer Rectifier Unit. Rectifier Unit.

Materials used as the anodes are: Materials used as the anodes are: High Silicon Cast Iron AnodesHigh Silicon Cast Iron Anodes MMO AnodesMMO Anodes Platinized Titanium AnodesPlatinized Titanium Anodes Platinized Niobium/Tantalum AnodesPlatinized Niobium/Tantalum Anodes

To note that all anodes perform differently in different service To note that all anodes perform differently in different service environment. Besides, designing of ICCP System must consider the environment. Besides, designing of ICCP System must consider the potential in causing coating damage and generating stray currents that potential in causing coating damage and generating stray currents that affect other structures. affect other structures.

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Advantages:Advantages: High flexibilityHigh flexibility Applicable to a variety of applications.Applicable to a variety of applications. Current output may be controlled.Current output may be controlled. Not constrained by low driving voltage.Not constrained by low driving voltage. Effective in high resistivity soils.Effective in high resistivity soils.

Disadvantages:Disadvantages: Higher maintenance.Higher maintenance. Higher operating cost.Higher operating cost. May cause interference on other structures.May cause interference on other structures.

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+ve+ve-ve-ve

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Figure shown is the Transformer Rectifier Unit (TRU) which supply power. Figure shown is the Transformer Rectifier Unit (TRU) which supply power.

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Figure shown is the Sled Anode. It Figure shown is the Sled Anode. It also called High Silicon Cast Iron.also called High Silicon Cast Iron.

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Figures shown are the LIDA TSAFigures shown are the LIDA TSATMTM Anodes: Mixed Anodes: Mixed Metal Oxide (MMO) on titanium anode material and Metal Oxide (MMO) on titanium anode material and designed to provide superior protection of offshore designed to provide superior protection of offshore platforms.platforms.Dead WeightDead Weight

AnodesAnodes

Supporting Supporting RopeRope

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Figure (left) shown are LIDA Tubular Figure (left) shown are LIDA Tubular Anodes: Titanium tubes with Mixed Anodes: Titanium tubes with Mixed Metal Oxide coating. MMO is a Metal Oxide coating. MMO is a crystalline and electrically-conductive crystalline and electrically-conductive coating.coating.

Figure (right) shown are LIDA Wire Figure (right) shown are LIDA Wire Anodes: Copper Titanium wire Anodes: Copper Titanium wire with MMO coating. In two with MMO coating. In two diameter, 1.5 mm and 3 mm.diameter, 1.5 mm and 3 mm.

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Figure (left) shown is the LIDA Pack Figure (left) shown is the LIDA Pack Canister Wire Anode: For shallow Canister Wire Anode: For shallow vertical and horizontal surface vertical and horizontal surface groundbeds, wet, and marshy soil groundbeds, wet, and marshy soil condition. condition.

Figure (right) shown is the LIDA Figure (right) shown is the LIDA Rod Anodes: Comprised of Rod Anodes: Comprised of Titanium substrate with Mixed Titanium substrate with Mixed Metal Oxide Coating.Metal Oxide Coating.

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Sea BedSea Bed

Sea WaterSea Water

Sea LevelSea Level

Splash ZoneSplash Zone

Mooring DolphinMooring Dolphin

Coal Tar Epoxy CoatingCoal Tar Epoxy Coating

Denso Paste & Denso TapeDenso Paste & Denso Tape

SEASHIELD 2000SEASHIELD 2000Smart Banding Smart Banding SystemSystem

Aluminum AnodesAluminum Anodes

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