Topic: Pipelines for hydrogen transport and the nature of gaseous hydrogen embrittlement

Speaker: Prof. Yufeng Cheng

University of Calgary，Canada

Time: 14:00-16:00,(Tues.) Nov. 12^th,2024

Venue: Room 403,Shi Changxu Building,IMR CAS

Abstract

Hydrogen has been regarded as a critical player in energy transition and the achievement of net-zero target. Pipelines represent the most economical, efficient, and effective means for transporting gaseous hydrogen in large volumes across long distances, contributing to the realization of a comprehensive hydrogen economy. However, steel pipelines are susceptible to the occurrence of hydrogen embrittlement in high-pressure gaseous environments. The hydrogen embrittlement problem jeopardizes the structural integrity, potentially leading to pipeline failures.

When compared to the hydrogen embrittlement in aqueous environments,gaseous hydrogen embrittlement manifests distinct features in the generation of hydrogen atoms and their adsorption and absorption in steels. Without a thorough understanding of the nature of this phenomenon,as well as appropriate testing methods and assessment techniques,it becomes extremely difficult to mitigate and control the issue. This is particularly crucial given the growing development of hydrogen pipelines globally.

This talk is prepared based on the author’s latest research and the interactions with worldwide researchers on gaseous hydrogen embrittlement. It imparts the essential nature and features of gaseous hydrogen embrittlement occurring on pipelines. These include the generation of hydrogen atoms from gaseous hydrogen molecules by the dissociative adsorption mechanism at specific sites on steel surface based on the orbital hybridization through electron transfer between hydrogen and iron atoms. Then the talk analyzes the deformation, fracture and fatigue behavior of steels in high-pressure hydrogen gas environments. The modeling and measurement results of hydrogen accumulation at surface defects on pipe body are introduced. Through a throughout examination of existing knowledge, the talk proposes possible methods for quantitative evaluation of the susceptibility of pipelines to gaseous hydrogen embrittlement.