corrosion in offshore wind energy a major...
TRANSCRIPT
Harald van der Mijle Meijer
Corrosion in offshore wind energy
‘a major issue’
22
Corrosion in offshore wind energy
A major issue
• Introduction TNO Den Helder
• What are the relevant types of corrosion?
• How to detect, manage and control corrosion
• Conclusion
3
TNO Science and Industry - Den Helder
• Surface protection group
• Corrosion and anti-fouling
research since 1964
• 18 employees
• 2007: new facilities completed
• Development of Maritime Research
Campus
4
Corrosion damage
Current situation
• Unexpected corrosion
damage
GDP NL600 billion euro
Direct annual costs due to corrosion:
18 billion euro
4
Improved correlation of accelerated tests within long-term performance
Early detection of corrosion mechanisms
Reduction corrosion damage
5
Offshore wind turbine relevant types of corrosion
Main shaft bearingGearbox
Brake
Tower, hubStairs, doors
Control unitCooling and
ventilation system
Monopile internalGrit connection
Transition pieceBoatlanding
J-tubes
6
Offshore wind turbine
Coating
• Coating
• Protection
• Bonding
• Plasticity
• Durability
• Failure modes
• Degradation
• Mechanical failure
• Blistering
• Topics
• Selection coating system
• Application
• Repair and maintenance
• Quality control
7
Offshore wind turbine foundation• Environmental conditions
• Flowing sea water
• Sea spray
• Temperature variations
• Biofouling
• Deaerated sea water (inner side)
• Corrosion risks
• Uniform corrosion
• Local corrosion:
• Microbiologically Influenced Corrosion (MIC)
• Pitting
• …
8
Microbiologically influenced corrosion (MIC)
• MIC
• Initiation and acceleration of corrosion due to the interaction
between microbial activity and construction materials
• Applications
• Offshore constructions, piping, ship ballast tanks, sprinkler
systems, water infrastructure
• Example of MIC: Accelerated Low Water Corrosion (ALWC)
9
Offshore wind turbine foundationBiofouling and corrosion phenomena
Types of corrosion
Severe corrosion splash zone
Tidal zone
Accelerated low water corrosion (ALWC)
Local corrosion under cluster of mussels
Local corrosion under soil
Seaweed
Mussels
Hydroids
Large cluster of mussels
Types of fouling
HWL
LWL
10
Offshore wind turbine foundation
Accelerated Low Water Corrosion (ALWC)
• ALWC occurs on steel surfaces below the tidal low water mark to
seabed influenced by growth of bacterial colonies (MIC)
• Applications
• Offshore structures, Harbour piling
• Remedy
• Cathodic protection
(sacrifacial anodes or impressed current)
• Coating
11
Corrosion testing techniques
Electrochemical Impedance Spectroscopy (EIS)
counter electrode
reference electrode
electrolyte
working electrode
EIS test on site
Visual corrosion after 720 days
Early warning
1.00E-11
1.00E-09
1.00E-07
1.00E-05
1.00E-03
1.00E-01
0 100 200 300 400 500 600
Duur expositie (dagen)
Y0
Corrosion detected after 250days
Coating
qualification
12
Corrosion testing techniques
Electrochemical Noise Measurement (ENM)
electrolyte
reference electrode
IE
workingelectrode 1
workingelectrode 2
Uniform corrosion carbon steel
Local corrosion MIC (thiooxidans)
13
Offshore wind turbine – sensor techniques
Transition piece/J-tubeCoating sensor (EIS)
Monopile externalBiofouling sensor / Biocorrosion sensor
NacelleCorrosivity sensor
Tower / HubCoating sensor (EIS)
Monopile internalBiocorrosion sensor
14
Offshore windfarms
Remote monitoring and diagnostics
14
Relevant data
Co
rro
sio
n A
Co
rro
sio
n B
Co
rro
sio
n C
Co
rro
sio
n D
Co
rro
sio
n E
Co
rro
sio
n F
15
Design
Risk analysis
Testing
Development phase
Requirements
Quality and control
Manufacturing
Design phase corrosion prevention and control
Modelling
Life time
predicition
Monitoring and control
Operation and maintenance
Corrosion aspects
Types of corrosion
Corrosion preventionMaterials selection
Accelerated corrosion testing
Corrosion preventionquality testing
Corrosion sensoringand monitoring
16
Conclusion
• Tailor made corrosion prevention in windfarm development phase
• Remote diagnostics (critical parts) and modelling
• Early warning and control
• Reduction maintenance and operational costs
17
“Offshore technology”
‘The Silent War’ – John Craven
