Corrosion in offshore wind energy. a major issue. Harald van der Mijle Meijer

Transcription

1 Corrosion in offshore wind energy a major issue Harald van der Mijle Meijer

2 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 2

3 TNO Science and Industry - Den Helder Surface protection group Corrosion and anti-fouling research since employees 2007: new facilities completed Development of Maritime Research Campus 3

4 Corrosion damage Current situation Unexpected corrosion damage Improved correlation of accelerated tests within long-term performance GDP NL 600 billion euro Reduction corrosion damage Direct annual costs due to corrosion: 18 billion euro Early detection of corrosion mechanisms 4

5 Offshore wind turbine relevant types of corrosion Control unit Cooling and ventilation system Main shaft bearing Gearbox Brake Tower, hub Stairs, doors Transition piece Boatlanding J-tubes Monopile internal Grit connection 5

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 6

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 7

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) 8

9 Offshore wind turbine foundation Biofouling and corrosion phenomena Types of fouling Types of corrosion Seaweed Mussels HWL LWL Severe corrosion splash zone Tidal zone Accelerated low water corrosion (ALWC) Hydroids Local corrosion under cluster of mussels 9 Large cluster of mussels Local corrosion under soil

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 10

11 Corrosion testing techniques Electrochemical Impedance Spectroscopy (EIS) Early warning 1.00E E E-05 reference electrode electrolyte counter electrode working electrode Y0 1.00E E E Duur expositie (dagen) Corrosion detected after 250days Visual corrosion after 720 days Coating qualification 11 EIS test on site

12 Corrosion testing techniques Electrochemical Noise Measurement (ENM) I E reference electrode electrolyte Uniform corrosion carbon steel working electrode 1 working electrode 2 Local corrosion MIC (thiooxidans) 12

13 Offshore wind turbine sensor techniques Nacelle Corrosivity sensor Tower / Hub Coating sensor (EIS) Transition piece/j-tube Coating sensor (EIS) Monopile internal Biocorrosion sensor Monopile external Biofouling sensor / Biocorrosion sensor 13

14 14 Offshore windfarms Remote monitoring and diagnostics Corrosion A Corrosion B Corrosion C Corrosion D Corrosion E Corrosion F Relevant data

15 Design phase corrosion prevention and control Corrosion aspects Development phase Requirements Types of corrosion Design Corrosion prevention Materials selection Risk analysis Testing Accelerated corrosion testing Modelling Life time predicition Manufacturing Quality and control Corrosion prevention quality testing Operation and maintenance Monitoring and control Corrosion sensoring and monitoring 15

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 16

17 Offshore technology The Silent War John Craven 17

18 18 Thank you for your attention