Extensive infrastructure exists for the transport of natural gas and it is an obvious step to assess its use for the transportation of hydrogen. The NATURALHY project is a major “Integrated Project” which has been selected for funding by the European Commission within the Sixth Framework Programme (started in May 2004). The objective is to prepare the European natural gas industry for the introduction of hydrogen by assessing the capability of the natural gas infrastructure to accept mixtures of hydrogen and natural gas. Key issues are durability of pipeline material, integrity management, safety aspects, life-cycle and socio-economic assessment and end-use. This abstract aims to give a brief overview on the work package “Pipeline Integrity” [www.naturalhy.net].
The addition of hydrogen to natural gas can lower, under certain circumstances, the toughness and the fatigue properties of pipeline steels. Therefore the pipes are more sensitive to the presence of defects. In order to ensure that technically proper and economically viable integrity management can be performed on the pipelines transporting hydrogen – natural gas mixtures, a systematic approach is undertaken in the NATURALHY project to establish an integrity management tool (IMT) specification and software aiming to predict the probability of failure. The work comprises sensitivity analyses of critical defects and defect sizes; performance assessment of inspection tools for detecting cracks and crack-like defects and the investigation of IMT parameters as functions of tool performance, defect distributions, inspection intervals and repair strategies. Furthermore currently applied repair technologies have been evaluated concerning their suitability for service with hydrogen.
The IMT specification will provide guidance to the transportation companies in order to ensure that they can take care of the pipeline integrity without a long-term “trial and error” phase in order to adapt existing systems to changed requirements.