Basis corrosion coating &CP system for pipeline in Oil & Gas Sector

EPC of New Refinery Project Package #5,

Kuwait

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Date: February 2016

ZOR#5 Subsea Pipeline Team

Corrosion Coating & CP System For Oil &Gas Pipeline

Date : 8th Jan. 2017

Prepared by : Quan PH

Issued For : Internal Training

Al-Zour Refinery Project Package #5,

Kuwait Date : Jan. 2017 0


Kuwait

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Date: February 2016

CONTENTS

Al-Zour Refinery Project Package #5,

Kuwait Date : Jan. 2017 1

1. Introduction

2. Rate of Corrosion

3. Corrosion Coating System

4. Cathodic Protection System


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Date: February 2016Date : Jan. 2017

This presentation aims to give the basis information for corrosion coating system of

pipeline and application of Cathodic Protection system for onshore and offshore in

Oil & Gas Sector .

Subsea pipelines and structure shall be protected from corrosion using a combination

of coatings and CP. The CP system shall be designed to maintain the electrochemical

potential of exposed metal surfaces within a range that controls corrosion within

acceptable limits and without causing material damage for the specified design life of

the asset.

This presentation covers some technical points from detailed design until completion

of site installation by necessary testing. The relationship between corrosion coating

system and CP system for anticorrosive property to be analyzed as well.

1. Introduction

2


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1. Introduction

3

The guideline for testing and criteria presented is referred to DEPs as following:

- DEP 31.40.30.31 External Polyethylene And Polypropylene Coating For Line Pipe:

Applied for factory corrosion coating

- DEP 31.40.30.37 External Field Joint And Rehabilitation Coating Systems For Line:

Applied for field coating

For Cathodic Protection:

- Project Variation P4049N-0000-DE10-VAR-0091_Design Cathodic Protection System

- ISO 15589-2:2012 Petroleum, petrochemical and natural gas industries — Cathodic

protection of pipeline transportation systems

- DEP 30.10.73.32 Design Of Cathodic Protection Systems For Offshore Pipelines

(Amendments/Supplements To Dnv Rp B401)


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When pipeline is either buried or submerged in water, corrosive environment

constitute between metal surface and its environment. The corrosion is the damage of

a substance which is usually a metal material.

The rate of corrosion depends on various parameters including:

- Type of applied corrosion coating and CP system

- Pipeline operating temp.

- Surrounding condition (electrolytic property)

- Soil quality and burial status

- Interface with other facility

To avoid corrosion of pipeline in design life, the corrosion coating shall be

appropriately selected and the CP system to be supplement in compensation of

electrochemical potential.

4

2. Rate of Corrosion


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3. Corrosion Coating – Selection Criteria

5

The type of corrosion coating to be selected based on below various considerations:


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3. Corrosion Coating – Selection Criteria

6

On design point of view, the most important aspect for selection of corrosion coating

is performance ability which shall be in compliance with project specification, applied

standard and to satisfy the CP designed. Below are main points for consideration:

- Project requirements

- Environmental service exposure (seawater, soil, etc.)

- Service temperature (depend on max. conveyed fluid temperature)

- The anticorrosive property of coating system (As shown in page 17)

For application in Oil & Gas pipeline, there are 3 most popular corrosion coating

systems that were qualified & certified through many projects:

- FBE

- 3LPE

- 3LPP


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3. Corrosion Coating – FBE

7

FBE is a high performance anti-corrosion coating that provides excellent protection

for small and large diameter pipelines with moderate operating temperatures.


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Typical Properties:

- Min. pipe diameter : 3.5”

- Max. pipe diameter : 48”+

- Min pipe length : 18’

- Max. pipe length : 82’

- Min. recommended handling& construction temperature : -30C

- Max. recommended operating temperature : 110 C

Application:


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9

Product Application Process:


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3. Corrosion Coating – 3LPE

10

This anti-corrosion system consists of a high performance fusion bonded epoxy

(FBE) followed by a copolymer adhesive and an outer layer of polyethylene which

provides tough, durable protection.

First layer: primer (liquid or powdered fusion

bonded epoxy (FBE)). Continuous thin layer resistant

to the corrosive agents. Guarantee a suitable

adhesion of the coating to the steel.

Second layer: co-polymer or modified polyethylene

adhesive. Guarantee a suitable adhesion between the

upper polyethylene layer and the primer.

Third layer: polyethylene. It provides good

mechanical strength, mechanical protection and

electric insulation.


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11

Typical Properties:

- Min. pipe diameter : 2”




- Min. recommended handling& construction temperature : -40C

- Max. recommended operating temperature : 85 C

Application:


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3. Corrosion Coating – 3LPP

13

This anti-corrosion system consists of a high performance fusion bonded

epoxy (FBE) followed by a copolymer adhesive and an outer layer of polypropylene

which provides the toughest, most durable pipe coating solution available.

First layer: primer (liquid or powdered fusion

bonded epoxy (FBE)). Continuous thin layer resistant

to the corrosive agents. Guarantee a suitable

adhesion of the coating to the steel.

Second layer: co-polymer adhesive. Guarantee a

suitable adhesion between the upper polypropylene

layer and the primer.

Third layer: polypropylene. It provides very good

mechanical strength, mechanical protection and

electric insulation.


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14

Typical Properties:

- Min. pipe diameter : 3.5”




- Min./Max. recommended handling& construction temperature : -20C to 110 C

- Max. recommended operating temperature : -20C to 140 C

Application:


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3. Corrosion Coating – Comparison Table

16


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3. Corrosion Coating – Comparison Table

17

Affection of coating system to CP design:


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3. Corrosion Coating – Internal coating

18

Epoxy Lining (Application Example):

This lining is applied by layering one or several coats of paint or by spraying epoxy powder.

1. The pipe is preheated to eliminate humidity

2. The interior surface is shot-blasted to remove mill scale and rust, obtaining a metal surface

which facilitates the adhesion

3. When epoxy powder is fused, the pipe is preheated to 238°C, in order to quickly cure the epoxy.

4. The pipe is rotated and the lining is sprayed from a set of nozzles which moves inside the pipe.

5. When paint is used, it is dried by blowing hot air through the pipe.


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3. Corrosion Coating – Compatible FJC System

19

Fusion Bonded Epoxy (FBE)

FBE

100% solid liquids, epoxy, epoxy‐urethane

Heat‐shrink sleeves (HSS)

Cold and hot‐applied tapes

Three layer polyethylene (3LPE)

Heat‐shrink sleeves (HSS), Optional for FBE

Multilayer flame spray with PE

Three layer polypropylene (3LPP)

Heat‐shrink sleeves (HSS), Optional for FBE

Multilayer flame spray with PP

FBE, spray applied adhesive, co‐extruded PP

FJC system selection:

Corrosion Control

To supplement CP system

Mechanical protection

Design codes specify


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3. Corrosion Coating – FJC - HSS Installation guide

20

Example for installation of HSS (Refer [Att-1] for full document)

Example for HSS product (Refer [Att-2] for full document)

Att1_HSS installation guideline-.pdf

Att2_MS65.pdf


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3. Corrosion Coating – Qualification and Testing

21

With reference to DEP 31403037, various

testing is required for qualification of

corrosion material (both factory and

field application). For FJC procedure

qualification:

- Surface finishing after blast cleaning

- Coating thickness

- Holiday test

- Coating adhesion

- Impact resistance

- Indentation

- Flexibility

- Hot water soak

- Cathodic disbonding resistance

- Thermal ageing

- Lap shear

- Degree of cure of FBE (if any)

- Microscopic examination

- Self-healing

- Drip resistance

- Peel to outer layers

- Destructive testing


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3. Corrosion Coating – Testing Frequency for FJC (DEP 31403037)

22

As Salt test


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4. Cathodic Protection System - General

23

The principle of cathodic protection is in connecting an external anode to the metal

to be protected and the passing of an electrical DC current. To that all area of the

metal surface become cathodic and therefore do not corrode.

There is fundamental difference between CP system for offshore side and onshore

side consideration the surrounding electrolytic environment (water vs particular soil).

For offshore side, the CP system is sacrificial anode that is made by Indium

activated aluminium alloy or Zinc alloy normally (External anticorrosion system).

Type of offshore anode: 1. Bracelet, half-shell (Squared or tapered) 2. Long Slender

Stand-off or Flush-mounted


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Anode Typical Drawing – concrete coated pipe


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Anode Typical Drawing –coated pipe


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For onshore side, the CP system is either galvanic anode

(sacrificial type), where the current is a result of the

potential difference between the two metals [Att-3.1] &

[Att-3.2] or it may be an impressed current anode,

where the current is impressed from an external DC

power source. The isolation joint may be omitted if the

onshore impressed current CP system is designed to

ensure that there is no current drain from the offshore

pipeline sacrificial anodes to onshore (As per ISO 15589-

2:2002)

Type 2:

Type 1:

Att-3.1_NRP.pdf

Att-3.2_NSRP.pdf


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If sacrificial anode to be used for buried onshore pipeline, the soil condition surround

anode shall be electrolytic activation.

Example from NSRP project and current design of Al-Zour Refinery Project.

NRP project:

NSRP project:

Anode Installation Sketch


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The above type CP system can be applied for offshore side, but due to installation

restriction, it is not used for offshore pipeline other than structure, e.g. platform.


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4. Cathodic Protection System – CP system design

29

With reference to ISO 15589 -2:2012 (as specified by specification P4045ZOR-93-10-

43-908)


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With reference to ISO 15589 -2:2012 (as specified by specification P4045ZOR-93-10-

43-908)


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Affection of coating system to CP design:


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4. Cathodic Protection System – CP Survey

32

After pipeline installation, the anode shall be surveyed against potential criteria.

The potential are referenced to an SCE reference electrode, which are equivalent to a

silver/silver chloride reference electrode (Ag/AgCl/seawater) in 30.cm seawater.

CP survey applied at NSRP Project (by HHI/Geometra)


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4. Cathodic Protection System – CP Survey - Discussion

33


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4. Cathodic Protection System – CP Survey & Anode Spacing

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Following PV P4049N-0000-DE10-VAR-0091_Design Cathodic Protection System

Anode Spacing: as per section 8.1 of ISO 15589-2:2012

Anode Spacing: as per P4049N-0000-DE10-VAR-0091_0 Design Cathodic Protection

System


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4. Cathodic Protection System – CP Survey - MIJ

35

Monolithic Isolation Joint

The purpose of insulating joints installation on gas and oil pipelines, it is to ensure

electrical isolation among sections of pipelines preventing detrimental electrochemical

interaction among the sections themselves. Insulating joints are also used to ensure

effective current spreading on cathodic protection systems. Monolithic Isolation Joints

are coated to prevent corrosion and are 100% tested hydrostatically, electrically and for

weld performance.

Monolithic Isolation Joints provide electrical sectioning and passive protection against

corrosion, they are installed in inlet and outlet pipes, on meters, tanks, pumping

station, etc.

Monolithic Isolating Joints do not require maintenance, and they improve the cathodic

protection of gas, water and petroleum pipelines with important savings in operation

and maintenance cost.


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4. Cathodic Protection System – CP Survey - MIJ

36

Monolithic Isolation Joint

Example for MIJ [Att-4.1] and NSRP [Att-4.2]

Att-4 monolithic-isolation-joints-ASME-API.pdf

Att-4.2.pdf

Basis corrosion coating &CP system for pipeline in Oil & Gas Sector

Engineering

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