PetroCor Brochure

7/29/2019 PetroCor Brochure

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CORROSION

Corrosion may be defined as the chemical reaction of metal with a non-metal (or non-metals) in the surrounding environment, with the formation of compounds which arereferred to as Corrosion Products. The conversion of metal into a powdery, non-adherent, friable compound will result in the deterioration of the metallic construction orcomponent.

In simple terms, it basically involves two electrodes, i.e anode and cathode immersed inan electrolyte solution that conducts electricity. The corrosion process occurs whenpositive electric current flow from anode to cathode through the solution. Generally,corrosion occurs at the anode.

In view of the electrochemical nature of corrosion, cathodic protection system is nowwidely applied as an electrochemical method to be devised to control or preventcorrosion. Usually, the aim of designers is to control it within acceptable economic limitsrather than to prevent it. However, cathodic protection is restricted to environments ofsuitable conductivity. It is particularly suitable for steels immersed in sea water andestuarine water but is also widely used in other waters and soil of suitable conductivity.

PRINCIPLES OF CATHODIC PROTECTION


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SACRIFICIAL METHOD

No external current source is required with this method. Anodes of suitable metals ofmore negative potential than steel are attached to the structure to provide electricalcontact. This produces a cell in which the steel is the cathode, the anode materialcorrodes, so must be replaced periodically. The essential requirement for the anodematerial is its ability to polarize the steel to potential where it either does not corrode orcorrodes at an acceptable rate. Other requirements are reasonable cost, ability to bemanufactured to suitable shapes and sizes even and reasonably uniform corrosion.

Zinc, Aluminum and Magnesium are used in marine situations. All are sufficientlynegative to act as anodes to protect steel in sea water. However, in practice, the exact

compositions of these metals when used for anode manufacture are important. Certainalloying elements markedly influence the performance of the metals as anodes forcathodic protection.

The composition must be such as to produce the following properties:

(i) A sufficiently negative potential to ensure cathodic protection in a particularenvironment.

(ii) Ability to continue to corrode during use and not to develop a passive orprotective film on the surface.

(iii) A high anode efficiency.

The advantages of the sacrificial anode method are:

(i) Can be used where there is no power.

(ii) Initial cost cheaper.

(iii) Less supervision required.

(iv) Installation is comparatively simple and additional anodes can easily be added ifthe initial proves to be inadequate.

(v) The anodes cannot be fitted incorrectly, e.g. so that current is supplied in thewrong direction, causing additional corrosion instead of protection.

(vi) Generally, over protection does not occur.



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+

IMPRESSED CURRENT METHOD

The basic principle of the method is illustrated in the following figure:

The DC current for protection is supplied from external source, delivered throughanode (or group of anodes) and electrolyte to the structure to be protected. Thiscurrent will be polarized the structure cathodically, to a lower potential. If the potentialreaches protection potential, the corrosion is technically stopped. For steel of potentialof - 850 mV or lower against copper/copper sulphate (Cu/CuSO4) electrode iscommonly accepted as protection potential.

A range of materials can be used as anodes, such as graphite, high silicon iron,magnetite, mixed metals oxides, lead alloys, platinized titanium (tantalum or niobium),

and conductive plastics.

The advantages of the impressed current method are:

High current capacity can be supplied to protect large structures.

Fewer anodes are required.

The method is capable of better control to provide optimum performance.

Mostly lower initial cost required.

-

Current Flow

Anode Protected Structure

Electrolyte

+



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WELD ON TYPE

ANODE

TYPE

ANODE

WEIGHT

(Kg)

GROSS

WEIGHT

(Kg)

ANODE DIMENSION

(mm)

PIPE CORE DIMENSION

(mm)

La Ba Ta Lc Bc Tc

AAW 15 1.5 1.9 305 75 35 425 30 4

AAW 26 2.6 3.2 270 150 30 370 40 4

AAW 40 4.0 4.4 305 152 38 425 30 4

AAW 54 5.4 6.4 456 102 53 626 30 6

AAW 86 8.6 9.8 550 127 50 650 40 6

AAW 101 10.1 11.6 550 130 65 650 40 6

AAW 126 12.6 14.1 535 130 75 635 50 6

AAW 140 14.0 15.3 585 149 67 750 38 6

AAW 165 16.5 18.0 550 130 96 650 50 6

AAW 213 21.3 24.0 900 140 67 1100 50 6

Note: Other dimensions of anodes or cores are also available on request

ALUMINIUM SHIP HULL ANODE


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BOLT ON TYPE


ANODE

TYPES

GROSS

WEIGHT

(kg)

L

(mm)

W

(mm)

T

(mm)

Lc

(mm)

AAB5 1.0 200 100 20 110

AAB14 2.0 305 76 36 205

AAB25 2.9 300 150 25 160

AAB35 3.9 300 150 30 160

AAB40 4.4 300 150 40 160

AAB44 5.0 456 102 53 230

AAB60 6.4 300 200 40 160

AAB80 8.4 300 200 50 160

ALUMINIUM SHIP HULL ANODE


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WELD ON TYPE

ANODE

TYPE

ANODE

WEIGHT

(Kg)

GROSS

WEIGHT

(Kg)

ANODE DIMENSION

(mm)

PIPE CORE DIMENSION

(mm)

La Ba Ta Lc Bc Tc

ZAW 18 1.8 2.0 170 75 25 230 30 4

ZAW 42 4.2 4.6 305 75 38 425 30 4ZAW 65 6.5 7.0 270 150 32 350 30 6

ZAW 80 8.0 8.6 305 152 32 425 30 6

ZAW 100 10.0 10.6 305 152 38 425 30 6

ZAW 110 11.0 12.0 400 150 32 530 40 6

ZAW 140 14.0 15.1 456 102 53 600 40 6

ZAW 200 20.0 21.4 580 142 45 720 40 6

ZAW 250 25.0 26.4 580 142 53 720 40 6


ZINC SHIP HULL ANODE


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BOLT ON TYPE

ANODE

TYPES

GROSS

WEIGHT

(Kg)

L

(mm)

W

(mm)

T

(mm)

Lc

(mm)

ZAB11 1.5 150 75 25 75

ZAB22 2.6 200 100 20 110

ZAB31 3.5 200 100 30 110

ZAB36 4.2 305 76 36 205

ZAB69 7.3 300 150 25 160

ZAB79 8.3 300 150 30 160

ZAB100 10.4 300 150 40 160

ZAB114 12.0 456 102 53 230

ZAB158 16.3 300 200 40 160

ZAB200 20.5 300 200 50 160


ZINC SHIP HULL ANODE


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HARBOUR AND JETTY ANODE

ANODE

TYPE

ANODE

WEIGHT(Kg)

GROSS

WEIGHT(Kg)

ANODE DIMENSION

(mm)

PIPE CORE

DIMENSION

(mm)

La B1 B2 T Lc Dc H

AJA 42 42 47 1500 92.5 130 100 2000 20 140

AJA 65 65 70 1500 100 143 140 2000 20 140

AJA 80 80 85 1500 125 150 150 2000 20 140

AJA 95 95 100 1500 145 165 160 2000 20 140

AJA 110 110 118 1500 150 180 170 2000 25 160

Note: Other dimension of anodes or cores are also available on request

ALUMINIUM JETTY ANODE


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CORE: STAND OFF BENT PIPE

ANODE TYPE

ANODEWEIGHT

(Kg)

ANODE DIMENSION(mm)

PIPE CORE DIMENSION(SCH 80)

La B1 B2 Ta Lc (mm) Dc (inch)

APF-100-SOBP 100 1500 160 210 150 1900 2.0

APF-123-SOBP 123 1750 170 220 150 2150 2.0APF-150-SOBP 150 2000 170 215 160 2400 2.0

APF-200-S0BP 201 2450 200 225 155 2850 2.0

APF-250-SOBP 250 2450 220 280 180 2850 3.0

APF-300-S0BP 300 2450 250 330 200 3050 4.0

APF-350-SOSP 350 2450 252 299 227 3050 4.0

APF-400-SOBP 400 2450 280 330 240 3050 4.0

APF-500-SOBP 500 2450 300 380 260 3050 4.0

CORE: STAND OFF STRAIGHT PIPE

ANODE TYPE

ANODEWEIGHT

(Kg)

GROSSWEIGHT

(Kg)

ANODE DIMENSION (mm)PIPE CORE DIMENSION

(SCH 80 )

La B1 B2 Ta Lc(mm)C

(mm)Dc

(inch)

APF-100-SOSP 100 110 1500 160 210 150 1300 1100 2.0

APF-123-SOSP 123 135 1750 170 220 150 1150 1350 2.0

APF-150-SOSP 150 164 2000 170 215 160 1800 1600 2.0

APF-200-S0SP 201 218 2450 200 225 155 2210 1910 2.0

APF-250-SOSP 250 285 2450 220 280 180 2210 1910 3.0

APF-300-S0SP 300 352 2450 250 330 200 2210 1910 4.0

APF-350-SOSP 350 402 2450 252 299 227 2210 1910 4.0

APF-400-SOSP 400 452 2450 280 330 240 2210 1910 4.0

APF-500-SOSP 500 552 2450 300 380 260 2210 1910 4.0Note: Other dimensions of anodes or cores are also available on request

ALUMINIUM PLATFORM ANODE


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BRACELET ANODE

ANODE

TYPE

I.D (ins) O.D (ins) THICKNESS

(inch)

LENGTH

L

(inch)

GAP

G

(inch)

NETT

WEIGHT

(lbs)

GROSS

WEIGHT

(lbs)

PABA 40 4.81 6.81 1 17.2 1.5 25 29

PABA 60 6.94 8.94 1 16 1.5 43 47

PABA 80 8.75 12.75 2 15.5 2 66 71

PABA 100 10.87 14.87 2 15.5 2 80 88

PABA 120 12.87 16.87 2 15.5 2 93 103

PABA 140 14.37 17.37 1.5 15.5 2 103 118

PABA 160 16.25 19.25 1.5 15.5 2 118 134

PABA 180 18.31 21.81 1.75 15.5 3.5 145 162

PABA 200 20.50 24.50 2 14.5 2 160 174

PABA 240 24.16 28.16 2 16 2 181 209


ALUMINIUM PIPELINE ANODE


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ALUMINIUM ANODE

The PetroCor Aluminium Alloy Anodes are made from the highest purity aluminium ingot to

meet the technical requirement as follows:

ELEMENTCHEMICAL COMPOSITION ( % )

ASALUM I ASALUM II

Si 0.10 max 0.10 max

Fe 0.13 max 0.13 max

Zn 3 - 5 4 - 10

In 0.04 0.02

Cu 0.01 max 0.01 max

Al Balance Balance

Efficiency 95 % 90 %

Electrochemical capacity in seawater

at ambient Temperature2700 Amp.Hr/Kg 2550 Amp.Hr/Kg

Consumption rate in seawater at

ambient temperature3.25 Kg/Amp.Year 3.45 Kg/Amp.Year

Note: Other compositions of material are also available on request

ENGINEERING INFORMATION


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ZINC ANODE

The Zinc Anodes are made from the special grade ingot of minimum purity 99.995%. Alloying

additions of special element is added to increase the anode efficiency and to improve the

uniformity of corrosion. The chemical composition is equivalent to US military Specification

18001-H.

ELEMENT CHEMICAL COMPOSITION ( % )

Cu 0.005 max

Al 0.10 0.50

Si 0.125 max

Fe 0.005 max

Pb 0.006 max

Cd 0.025 0.15

Zn Balance

Efficiency 95 %

Potential -1.05 Volts vs Ag/AgCl

Electrochemical capacity in seawater at

ambient temperature780 Amp.Hr/Kg

Consumption rate in seawater at ambient

temperature11.25 Kg/Amp.Year

Note: Other compositions of material are also available on request



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MIXED METAL OXIDE (MMO) ANODE

Materials : Mixed Metal Oxide (MMO) coated TitaniumSubstrate : Titanium to ASTM B338Shape : TubularSize : 0.0254 m diameter x 1 m longCurrent Density : 100 A/m in carbonaceous backfill for soil applicationAnode current output : 8 ampere

Mixed metal oxide anodes have proven to operate effectively in all types ofenvironments, including areas with extremely low pH levels (under 1), and high chloride

concentrations.

Note: Other dimension of material are also available on request



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TRASFORMER RECTIFIER(OIL COOLED)

Input voltage

115 V or 240 V single-phase

380 / 400 / 440 / 460 /480 V three-phase

Frequency

50 or 60 Hz

Output

can be supplied in various currents and voltages ranging from

12 to 100 volts and 10 to 500 Amperes.

Voltage

12, 18, 24, 30, 36, 40, 50, 75, 100 Volts

Current

10, 20, 30, 40, 50, 60, 75, 100, 150, 200, 300, 400 or 500 Amp

Control

Manual continuously variable or adjustable in 15, 20, 24 or 63 steps

Automatic

constant current or constant potential

Protection

Output fuse and lightning arrestor

Output Rating

Continuous at full output

Main standard

- Auto and double wound transformer components

- Silicon or selenium bridge rectifier

- Output ammeter and voltmeter

- Surge arrester

- Fuses

- Enclosure

Standard Tank

- Lockable weatherproof control cabinet with viewing window

- Fittings

- Oil filling cap and drain plug (for oil-cooled units)

- Thermometer pocket and level gauge

- Silica gel breather and spare cartridge

- Earthing terminal- Lifting lugs


Oil Cooled Manual Rectifier

Oil Cooled Variac Rectifier

Documents

PetroCor Brochure