Gaz de France - Isabelle Alliat TNO – Jan Heerings

1. Assessing the Durability and Integrity of Natural Gas Infrastructures for Transporting and Distributing Mixtures of Hydrogen and Natural Gas Gaz de France - Isabelle Alliat TNO – Jan Heerings

2. OBJECTIVES (1/2) How much % of H2 is acceptable? SAFETY = Potential leakages of H2 and failure of gas pipes • Effects of hydrogenon the durability of materials and components used in the natural gas transmission and distribution networks and end user infrastructure • What are the H2 leakages in steel pipes? in PE pipes? in gas appliances? • How does H2 effect the initiation and growth of defects in pipes? In which conditions? • Has H2 an ageing effect on PE pipes? • Etc.

3. Transmission pipelinesPotential Threats Combined Gas & Liquid Incidents 1990-2001 1000 900 800 700 600 Incidents 500 400 Liquid 300 Gas 200 100 0 Outside Other Corrosion Malfunction Force & 3rd Failures of Control/ (Various) Party Relief damage Equipment

4. Transmission pipesThreats, in more detail Corrosion Mechanical damage (Third party) • General • MIC • AC • DC • SCC • Dents • Gouges Material Imperfections • Weld defects • Laminations

5. Potential Effect of Hydrogen, in terms of material performance What is the combination of crack size, material and loading conditions representing the maximum allowable condition to rupture? Embrittlement Material Performance Fatigue Rate Fatigue Threshold How fast does a crack larger than the threshold grow ? At what K does an existing crack start to grow ?

6. Transmission pipelinesAssess the effect of H2 on steels • State of the art • Gaseous H embrittlement of steels • Degradation of steel ductility = more brittle • Easier initiation of internal cracks (with or without applied stress) • Delayed failure ruptures under mechanical loading • Reduced fatigue life • Reduced threshold stress intensity factor (KIH) for cracks initiation • Higher crack propagation rate under cyclic loading

7. Transmission pipelinesAssess the effect of H2 on steels • Scope = steels for pipes & welds & defects • Mechanical strength and fracture behaviour Fracture toughness Burst resistance Fatigue behaviour • Deterministic and Probabilistic Approaches

8. Transmission pipelinesAssess the effect of H2 on steels

9. Transmission pipelinesAssess the effect of H2 on steels • Experimental methodology Machined sample Tile cut in the pipes

10. Transmission pipelinesAssess the effect of H2 on steels Ring Glass cell Internal hydraulic pressurization room • Experimental methodology Part of pipes Closed-end pipes

11. Distribution networkAssess the permeability of PE • Purpose = identify the leakage of gas and assess the potential risks (safety) • Scope = PE for pipes (PE80, PE100) & welds (electro-fusion) • State of the art • Few works were published on H2 permeation • Quite thin literature on ageing of PE

12. Distribution networkAssess the permeability of PE • Permeation measurement • on samples & pipe sections and welds

13. Distribution networkAssess the permeability of PE a • First results • Permeability • Diffusivity

14. Distribution networkAssess the effect of H2 on ageing of PE Macroscopic behaviour Chemical link Macromolecular chain Microstructure IRTF TREF DMTA Mechanical properties Permeation behaviour DSC SAXS • Ageing testing • Impact of H2 on residual properties

15. Distribution networkAssess the reliability of gas meters • Purpose = identify the leakage of gas (safety) and assess the metering • Scope = domestic gas meters with polymer membranes • G4 (up to 6m3/h) and G6 (up to 10m3/h) • European manufacturers • Actaris • Elster • Kromschroeder • Nuovopignone

16. Inner gridsAssess the permeability of PE • Testing materials & devices used in houses • Scope = gas-valve combination, connection between end-using devices and house installation, and whole end-using device (like boiler) • Metals : copper, steels, cast iron, ductile iron, etc. • Polymers : PE, PVC, elastomers, etc. • This task starts at month 18 (October ‘05): definition of test conditions

17. Durability Assessment Tool • Develop new software tool for predicting damage impact on pipeline strength • Verification of software simulation : estimation of lifetime of networks • User guide for operation with NG/H2 mixtures • The results from the WP3 “Durability” will be used in the WP4 “Integrity” for updating the inspection, repair and integrity management tools

18. Operational Management of Integrity TNO – Jan Heerings

19. Balance between Integrity controlling factors Material Performance Mechanical loading (operations) Structural Reliability or PoF Defect size Inspection requirements Repair requirements Changing material performance changing acceptable defect size modified operating window modified inspection & repair requirements

20. Potential Effect of Hydrogen, in terms of maximum acceptable defect size Example of typical result : Various safety margins

21. Inspection requirements Which requirements are needed ? Which improvements are possible ? MFL Data from GE PII UT

22. Repair requirements Which requirements are needed ? Which improvements are possible ? • Grinding • Weld deposit • Metallic sleeves (bolted or welded) • Composite sleeves • Advanced metallic sleeves (GE PII ESR) • Cut and replace defective section of pipe

23. Integrity Management Threat Identification Repair & Mitigation Measures Integrity (PoF) & Consequence (CoF) Assessment Inspection & Monitoring Risk Evaluation

24. Challenge in Naturalhy Taking account of: • Percentage of hydrogen in mixture • Material of construction • Operating conditions • Age of pipeline, historical inspection data • CP measurement data and level of protection • Coating survey measurements Translation of changed material properties towards Decision-making on WHEN and HOW to INSPECT and REPAIR • Main deliverables: • Improved inspection methods • Improved repair methods • Integrity Management Tool & Resource Allocation

25. THANK YOU