Teaching experiment design of non-metallic sealing material performance in a hydrogen environment

In the context of the “double carbon” goal, hydrogen energy has gradually been promoted as a renewable energy source with the advantages of being green, flexible, having good combustion performance, and possessing high energy density. Hydrogen-doped natural gas pipelines are an effective way to enable large-scale, long-distance, safe, and efficient hydrogen transportation. However, the unique physical properties of hydrogen may affect the performance of pipeline sealing materials and pose a threat to transportation safety. Hydrogen blending in natural gas pipelines may not only degrade the performance of non-metallic sealing materials but also increase pipeline leakage. Because hydrogen is easier to ignite and explode than natural gas, the risk of pipeline transportation is greatly increased. The purpose of this study is to explore the performance evolution of non-metallic sealing materials in a hydrogen environment through systematic experimental teaching, to provide a basis for the optimization design and safety standard formulation of pipeline sealing systems, and to cultivate students' engineering practice ability and scientific research literacy.

This study designs and constructs an experimental teaching system for evaluating the performance of non-metallic sealing materials in a hydrogen environment, enabling students to gain a deep understanding of the performance degradation behavior of non-metallic materials under hydrogen exposure. The experimental teaching system combines experimental research and numerical calculation. The experimental research component consists mainly of two parts: aging experiments and permeation experiments, which are used to study the aging behavior and permeation characteristics of non-metallic materials in a hydrogen-doped environment. During the experiments, students' participation in the entire process of instrument operation, data recording, and phenomenon analysis was emphasized. In combination with numerical simulation methods, a simulation model of permeation and sealing performance of non-metallic sealing materials in a hydrogen environment was established.

The experimental results show that the volume swelling rates of ethylene propylene rubber and low-nitrile nitrile rubber after hydrogen-induced aging were less than 15%, and the mechanical property retention rates were greater than 85%, indicating the best anti-aging performance, while the performance of fluorine rubber was also favorable. In the permeation experiments, the permeability coefficients of tetrafluoro-propylene rubber and nitrile butadiene rubber were low, demonstrating excellent barrier properties. Among the eight non-metallic materials tested, fluorine rubber exhibited the best comprehensive performance in a hydrogen environment.

By constructing an experimental teaching system for evaluating the performance of non-metallic sealing materials in a hydrogen environment, this study clarified the aging and permeation behaviors of typical non-metallic materials under hydrogen exposure, providing an experimental basis for the selection and safety evaluation of sealing materials for hydrogen-doped natural gas pipelines. At the same time, the experimental system integrates frontier scientific research problems into practical teaching, effectively improving students' comprehensive abilities in high-pressure gas environment material testing, data modeling, and analysis for solving complex engineering problems, and provides an important teaching platform for cultivating engineering and technical talents to meet the needs of energy transformation.