Joining the DOE HyBlend Program, 18-R6160

Background

Hydrogen will be a key resource as the world seeks carbon-neutral energy sources, and utilizing hydrogen blended with natural gas (HyBlend) for power generation and heating will help to reduce greenhouse gas emissions. By using the existing pipeline infrastructure and conventional natural gas power generation machinery, greenhouse gas emissions can be readily reduced in the very near term. However, pipeline operators and power generating companies are concerned with the potential negative effects of blended natural gas on existing pipeline infrastructure and power-generating machinery. The Department of Energy (DOE) funded a team of six national labs to perform basic research on the effects of blended natural gas on existing pipelines and pipeline materials to address industry concerns. This team was required to secure industry and academic support through in-kind and cash contributions, and SwRI in-kind materials testing in high pressure hydrogen gas to evaluate the effect of hydrogen gas on vintage pipeline steel.

Approach

Through this in-kind project support, SwRI joined the national lab team and more than 20 industry and academic organizations to further investigate the effects of hydrogen on vintage pipeline steels. Engineering Critical Assessments are utilized by the industry to determine safe operating conditions, assess minimum detectable flaw sizes, and specify pipe inspection intervals. Mechanical properties such as fracture toughness and fatigue crack growth rates measured in representative environments are critical to accurately predict the mechanical performance of these pipelines and ensure integrity. SwRI, utilizing novel testing facilities, performs fracture toughness and fatigue crack growth rate testing in high pressure hydrogen gas to quantify the deleterious effects on these critical mechanical properties.

Accomplishments

SwRI completed a study on the effect of monotonically increasing displacement rate on the fracture toughness of a vintage pipeline steel in high pressure hydrogen gas for use in the engineering critical assessments. Fatigue crack growth rate testing was completed in air and high pressure hydrogen gas to investigate the effects of hydrogen gas on the crack growth rates at low cyclic crack driving forces. For the pipeline steel material tested, hydrogen caused a reduction in crack growth rates in the near-threshold regime. These two data sets will be utilized by industry stakeholders to perform engineering critical assessments to determine whether these vintage pipelines can be utilized for transport of blended hydrogen gas.