Hydrogen’s pure potential

The need for a shift in energy generation, transportation and usage to fulfil climate change objectives is acknowledged worldwide, with parties at COP28 agreeing to accelerate decarbonisation efforts.¹ While several competing technologies are vying for a role in this energy transformation, this article concentrates on the potential of hydrogen. Hydrogen provides an opportunity to leverage the existing extensive infrastructure of the fossil fuel industry and hydrogen blends, but there are risks involved.

High pressure steel transmission pipelines face a significant threat from hydrogen embrittlement, which can lead to cracking, blister-ing and weakness. This occurs when hydrogen infiltrates the pipeline material, causing corrosion of the steel pipe, valves, and fittings.

Using a case study that examines the implementation of a real-time system for simulating hydrogen pipelines, this article will evaluate the precision of various equations of state by utilising an operational pure hydrogen pipeline.

Hydrogen transportation

Transporting hydrogen in large commercial quantities is challenging due to its unique properties. The smaller size of the hydrogen molecules compared to natural gas allows it to diffuse with the pipeline material, leading to hydrogen embrittlement and the deterioration of the steel pipes.

Hydrogen also has a lower energy density than natural gas, requiring larger diameter pipelines to transport the same amount of energy. This makes long-distance transportation more expensive and less efficient.

While repurposing natural gas pipelines for hydrogen transportation can be beneficial it does require an analysis of operating procedures. Pipeline simulation can assist by modelling the changes in pipeline capacity with the change in fluid.

Hydrogen embrittlement risks

Hydrogen embrittlement is a process that occurs when hydrogen atoms are absorbed into a metal, causing it to become brittle and susceptible to cracking and fracture. This occurs when hydrogen atoms diffuse into the metal lattice, causing lattice distortion and weakening the metal’s ability to withstand stress.

Hydrogen embrittlement can occur in a variety of ways, but in the pipeline industry it’s commonly associated with when metals are exposed to hydrogen gas or other hydrogen-containing com-pounds, such as water vapour or hydrogen sulfide.

Preventing hydrogen embrittlement requires a combination of measures, including proper material selection, design and maintenance. In many cases, it’s essential to use materials that are resistant to hydrogen embrittlement, such as high-strength alloys, that have been specifically designed to resist hydrogen embrittlement.

Ensuring the safety of the public in industries such as hydrogen energy, chemical and oil refineries requires careful consideration of hydrogen embrittlement. The selection of a suitable pipeline material is critical in reducing the risk of this phenomenon. An alternative approach to reducing the risk of hydrogen embrittlement is the reduction of the concentration of hydrogen. This can be achieved by blending hydrogen with compounds such as natural gas to dilute the concentration.

The following case study demonstrates how an accurate hydrogen model can be achieved by the model tuning process and the selection of appropriate equations of state so that it can provide a more accurate prediction of the pipeline areas subject to hydrogen embrittlement.

Case study: pure hydrogen pipeline

Spanning 160 km from west to east, this pipeline has a mainline section divided into two branches with the southernmost branch splitting into two parallel pipes…

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Read the article online at: https://www.worldpipelines.com/special-reports/10062024/hydrogens-pure-potential/