Research on Mechanism of Methanol–Hydrogen Co-Transport Inhibiting Hydrogen Embrittlement in Pipeline Steel

Existing studies suggest that hydrogen embrittlement will occur in pipeline steel under a hydrogen environment, and gas is often used as a hydrogen embrittlement inhibitor. As one of the most effective hydrogen carriers, methanol may competitively adsorb with hydrogen on the surface of pipeline steel and inhibit the hydrogen embrittlement when co-transported with hydrogen through pipelines. Moreover, the low saturated vapor pressure of methanol is more conducive to its separation from hydrogen in the downstream. This study investigates the effect of methanol on hydrogen embrittlement in X80 steel through closed in situ tensile testing, revealing that methanol can effectively inhibit hydrogen embrittlement. Further molecular simulations confirm that the methanol liquid film acts as a hydrogen barrier. Through the adoption of methanol–hydrogen two-phase mixed transportation and the rational control of the gas–liquid flow pattern, it is promising to achieve the coordinated transportation of various hydrogen energy carriers while effectively inhibiting the hydrogen embrittlement of pipeline materials.