HYDROGEN BLENDING IN NATURAL GAS PIPELINES: STEEL INTEGRITY AND HYDROGEN EMBRITTLEMENT RISKS
Date
2024-11-25
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Abstract
The depletion of fossil fuel reserves, coupled with the environmental challenges of their combustion, primarily the acceleration of global warming, has shifted focus toward alternative energy sources. Hydrogen gas is a particularly promising option, as it burns cleanly without producing carbon dioxide and is widely recognized as a green energy carrier. Given the extensive infrastructure already in place for natural gas (NG) transportation, repurposing this network for transporting an NG-hydrogen blend could contribute significantly to achieving a carbon-neutral economy. Hydrogen-natural gas blending has gained considerable attention in recent years. However, a major challenge in this approach is the risk of hydrogen embrittlement (HE), a process where hydrogen atoms infiltrate the metal lattice, weakening the material's mechanical properties and potentially causing sudden, severe failures under stress. To assess the feasibility of hydrogen blending within the current NG distribution network, a thorough analysis of pipeline steels is crucial.
Description
This study examined the mechanical performance of two pipeline steels from the NG network through tensile, fatigue, fracture, and constant load tests. Using an electrochemical charging process, hydrogen absorption was induced in the steels, followed by immediate mechanical testing to compare hydrogen-charged samples with uncharged ones. Results show that hydrogen charging significantly degrades the mechanical properties of both steels. However, the degree of degradation is strongly influenced by factors such as the material’s microstructure, the hydrogen concentration, and the specific test conditions.
Keywords
Hydrogen embrittlement, Natural gas-hydrogen blending, Steel degradation