Converting to a Hydrogen Pipeline
The need for renewable energies is clear. However, this hydrogen economy will not succeed without a safe and efficient transport infrastructure. Existing gas networks and newly constructed hydrogen pipelines will meet a large part of this demand, and, as with any asset, the integrity management of hydrogen pipelines must be addressed.
Introducing hydrogen into an existing natural gas network comes with some challenges. Whether completely converting an existing asset to hydrogen transportation or introducing a hydrogen blend, regulatory requirements dictate a series of preparatory actions. Making this process digestible through a phased approach allows for a step-by-step guide that, in the end, results in a hydrogen pipeline.
Hydrogen Pipeline Integrity Assessment
Pipelines transporting hydrogen are still pipelines, so all the threats operators face with natural gas lines are still relevant. However, there are certain characteristics of hydrogen that may increase the risk of some threats more than others. Hydrogen has little effect on increasing the risk of metal loss, a large effect on cracking, a very large effect on fatigue, and an unknown effect on dents and gauges. In terms of cracking and fatigue, three factors to watch for are 1) a decrease in material toughness, 2) a decrease in ductility, and, therefore, the inevitable 3): an increase in the crack rate.
ROSEN delivers the full range of integrity services for hydrogen pipelines – from high-level procedural and organizational definitions to detailed engineering assessments. Common integrity issues specific to hydrogen pipelines are:
Hydrogen Material Testing
Hydrogen can have an adverse effect on the fracture and fatigue properties of steel. The magnitude of the effect can vary, depending on steel grade and microstructure, concentration of hydrogen, and other factors. Therefore, integrity assessments need to be based on the material properties in hydrogen, which are usually not known in case of existing lines and thus must be assessed as part of the process of (re)purposing the lines for hydrogen transportation. Guidance on the design of hydrogen pipelines is given in ASME B31.12, including fracture toughness testing.
ROSEN’s testing capabilities offer the possibility of conducting material and exposure tests in a hydrogen atmosphere (hydrogen blends and pure hydrogen) at a temperature of up to 200°C and a pressure of up to 150 bar. The facility is equipped to complete:
- Environmental fracture toughness tests
- Constant load/displacement KIH tests according to ASME B31.12
- Rising displacement J-R tests according to CSA CHMC 1
- Environmental fatigue crack growth tests according to CSA CHMC 1
- Tensile tests in hydrogen atmosphere
- Environmental slow strain rate tests
- Material testing of new pipe according to ASME B31.12
Hydrogen Inspection Technologies
Historically, in-line inspection (ILI) has been one of the most effective ways of gathering data points for the integrity management of pipelines; this doesn’t change for hydrogen pipelines. ILIs with hydrogen as a medium are possible, but, as with any other inspection project, knowledge of the operating conditions and pipeline routing is essential.
Of course, there are a few things to consider when preparing the tool itself. For example, all tool components and materials must be properly selected and verified to ensure the requirements of an inspection in hydrogen pipelines are met. Ideally, of course, pipeline cleanliness must be considered to ensure the most successful in-line inspection results, like for any other ILI project.
However, keeping these things in mind, any inspection technology available to inspect in natural gas pipelines is also applicable for inspection in hydrogen pipelines – and able to perform to the same technical specifications. Click here to learn more about our pipeline inspection solutions.
Crack Detection and Assessment
Hydrogen has a large effect on pipeline cracking, which makes cracks one of the main threats to hydrogen pipeline integrity. ROSEN uses an innovative inspection technology that generates ultrasonic sound waves and beams them into the pipe wall using electromagnetic induction with two interacting magnetic fields, without the need for a liquid couplant. This makes our EMAT technology the first choice for axial crack inspection in gas pipelines, as it works in a medium-independent way. Accurate continuous sizing of any crack depth is made possible by the right selection of EMAT wave modes. Appropriate baseline standards for the successful and effective management of pipeline integrity are applied, especially for pipeline conversion candidates. Click here to learn more about our pipeline crack detection and assessment services.
Material Property Determination
For re-purposing pipelines that were not designed or built for hydrogen service, knowing the range of different materials and pipe grades existing within a pipeline is vital to ensuring safe hydrogen transportation. ROSEN’s material property determination services have been developed to address pipe and material properties, thus putting an end to incomplete pipeline construction records.
- Pipe grade determination: ROSEN’s innovative material strength categorization service, RoMat PGS, provides a measurement of yield strength and an accurate determination of the pipe grade for each joint within the examined pipeline section.
- Hard spot detection: ROSEN’s dual magnetization service, RoMat DMG, provides a pipeline inspection solution that accounts for localized variations of the pipe wall’s metallurgical hardness – so called hard spots.
Please contact us and we will be happy to provide you with more information.
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