Session: MF-02-03 Materials for Hydrogen Service-Polymers 2

Paper Number: 123861

123861 - Investigating In-Situ Fracture Behaviors of Polymer Pipeline Materials in Hydrogen and Hydrogen-Methane Blended Gas Environments 

The existing natural gas pipeline infrastructure is being considered for the transportation of hydrogen and hydrogen-blend gas, as part of efforts to reduce greenhouse gas emissions and promote clean energy consumption. In the United States alone, there are nearly three million miles of transmission and distribution gas pipelines, with approximately half of them constructed using polyethylene. Consequently, it is crucial to investigate the compatibility of polyethylene pipeline materials with hydrogen and hydrogen-methane blend gas to ensure the safety and integrity of these pipeline infrastructures.

Polymer pipelines primarily consist of medium-density polyethylene (MDPE) and high-density polyethylene (HDPE). These materials have been proven to be durable and cost-effective in comparison to metallic pipelines. However, the majority of research on hydrogen compatibility has focused on metallic pipeline materials, leaving the interaction of hydrogen and hydrogen-blend gas with MDPE and HDPE largely unexplored.

In this study, we investigate the in-plane fracture behaviors of MDPE and HDPE exposed to hydrogen and hydrogen-methane blended gas. Single edge notch bending geometry is used. All tests are executed in-situ with the gas environment. The experimental results show a significant effect of the gas environment to HDPE specimens, reducing 5% (H₂) to 42% (Blended gas) of specific fracture energy compared to non-aged specimens. For the MDPE, the effects of the gas environment are insignificant. Fracture surfaces of the tested samples are observed using an electronic microscope and a X-ray micro-CT scan. The in-plane fracture surface of HDPE shows a pronounced dimple fracture pattern after exposure to hydrogen and blended gas. The expanded fracture pattern contributes to lower the specific fracture energy. From the X-ray CT-scan, we observe full 3D radiating cracks. These observations provide critical information for validating polymer pipeline materials when interact with hydrogen and hydrogen-blend gas.

Presenting Author: Seunghyun Ko Pacific Northwest National Laboratory

Presenting Author Biography: Dr. Ko is a material scientist at the Pacific Northwest National Laboratory. He focuses on polymer material compatibility with the hydrogen environment.

Authors:

Seunghyun Ko Pacific Northwest National Laboratory
Yao Qiao Pacific Northwest National Laboratory
Ethan Nickerson Pacific Northwest National Laboratory
Yongsoon Shin Pacific Northwest National Laboratory
Kee Sung Han Pacific Northwest National Laboratory
Wenbin Kuang Pacific Northwest National Laboratory
Kevin Simmons Pacific Northwest National Laboratory