Abstract

Polymers and continuous-fiber composites are likely to play an important role in the development of a reliable infrastructure for hydrogen production, distribution, storage and use. Reducing gas permeation through thermoplastic liners is currently a hot research topic, particularly in pipe applications where multi-layer liners are being adopted as cost-effective permeation barrier solution in high pressure service. The rapid depressurization of a high pressure H₂ equipment (pipes and pressure vessels) made of polymer composites, also known as rapid gas decompression (RGD), can lead to different types of damage such as cavitation, blistering, delamination or ultimately liner collapse. These damage mechanisms are mainly controlled by hydrogen desorption kinetics during decompression as well as the mechanical properties of the polymer/composite and interface strength. In an effort to progressively reduce cumbersome and costly RGD tests¹ by reliable prediction models, the present work proposes a simple continuum diffusion-deformation-damage model applicable to rapid hydrogen decompression in multilayer polymer liners used in thermoplastic composite pipes and hydrogen tanks. Some initial comparisons with experimental work are also presented and the limitations of the current approach are highlighted with suggested routes for future developments.

Figure 1:  Blistering damage in a multilayer PA-PE liner following rapid hydrogen gas decompression at 30 bar/min.

References

1. API SPEC 15S, 3rd Edition, April 2022 - Spoolable Reinforced Plastic Line Pipe.

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