From Hydrocarbons to Hydrogen: What Changes When It Comes to Safety?
By Megan Hine, Safe Energy Transition Business Development Manager, Draeger Safety UK
Megan Hine is Safe Energy Transition Business Development Manager at Draeger Safety UK, the global safety and medical technology leader. Responsible for driving awareness of safety within the energy transition and supporting customers in this sector, Megan has a wealth of experience working with a range of industries, in particular the oil and gas sector. Passionate about ensuring safety keeps pace within the UK’s energy transition, she is a frequent speaker on the topic.
Hydrogen is widely considered to be an essential part of the UK’s future energy independence and security, offering good applications for long term energy storage, and the potential to play an important role in levelling out the fluctuations of seasonal energy demand. As such, improved education and increased awareness in relation to hydrogen safety is critical for operators handling hydrogen equipment and for those overseeing its storage and transportation.
It might be said that hydrogen isn’t any more, or less, dangerous than other forms of energy but it is important to understand both the differences and similarities in order to fully appreciate how to approach safety protocols and therefore how to keep people safe where hydrogen is present.
For decades now, there has developed a good understanding of the risks posed by hydrocarbon gas and vapour releases. The behaviour of these molecules is well understood, and as a result, risk mitigation is mature.
The introduction of hydrogen as a key component of Net Zero provides a new molecule, and a new challenge to consider.
Hydrogen – the implications for gas detection
Hydrogen behaves very differently to hydrocarbons. Some of the differences are well documented, such as its colourless, odourless characteristics and wide flammability range in air, increasing the likelihood of explosive reactions.
It is, however, not necessarily more or less dangerous, but it will pose greater hazards in some circumstances, and lesser hazards in others.
For us to detect hydrogen as part of plant safety, there must be a leak, and whilst it is no more likely to leak than methane at low pressures, hydrogen is more likely to leak at higher pressures than methane.
The different characteristics of hydrogen bring implications for gas detection selection. For example, Infrared (IR) is blind to hydrogen, which means we are unable to use any devices from the IR portfolio – both point and open path IR detectors – to detect hydrogen. The practical implication here is that we lose the option of traditional optical large area gas detection.
Other detection options for hydrogen are available, however. These include catalytic bead sensors and electrochemical sensors, which can detect hydrogen in the 0-100% LEL (Lower Explosive Limit) range.
Most personal gas monitors utilise catalytic bead detection technology for all flammable gas hazards on account of its regular calibration and bump testing through typical operational procedures. In this instance, the device merely needs to be calibrated to the most reactive substance present, which is standard mobile gas monitoring procedure. We can also provide electrochemical hydrogen solutions for inert environments, and in fact this is from where our fixed gas detection EC solution evolved.
Hydrogen blending
When it comes to hydrogen blending with methane, again, an understanding of the gas detection and monitoring implications are important. Up to 20% H2 does not affect the combustion efficiency of methane-based combustion, however above 20% starts to affect the combustion efficiency. Therefore, blends that still have a majority of methane in the composition mean that traditional methane detection is still the best way to detect leaks in such instances:
- Point detection (using Infrared) – as previously mentioned, IR is incapable of detecting hydrogen itself (although as we will explore later, can detect a hydrogen flame). However, as the volume of natural gas (methane, CH4) is the larger volume present in blended hydrogen, and the method of detection is more reliable (immune to poisoning and fail safe) this would be the preferred point detection method where CH4 is present. To account for the lower volume of CH4 we recommend lowering alarm set points accordingly.
- Line of Sight detection – another option; we offer IR open path gas detection as a combustible gas detector, as above.
Acoustic gas detection
Ultrasonic gas leak detection provides a further option, which is particularly suited to wider area monitoring, for example outdoor process environments, and has the added advantage of detecting at an earlier stage (when the gas release or leak occurs, as opposed to waiting to detect a formed vapour cloud, or for that vapour cloud to ignite and produce a flame).
Ultrasonic detection operates by identifying sound waves generated by high pressure gas releases, of frequencies greater than the upper limit of the audible range for humans (greater than about 20 khz). The technology is not gas-specific, which can be both a positive, and a negative; not all gases are ‘unsafe’, therefore the system is susceptible to false alarms. But this technology does offer an extremely fast response to a potential problem, before an accumulation of the gas has built up.
Flame detection
We have touched on the challenges posed by hydrogen fires being almost invisible in daylight conditions. However, further protection from the risks associated with hydrogen releases can be obtained through flame detection technology using Infrared. Triple Infrared, or IR3, measures three different IR wavelengths, making it a very fast method of detection in the event of a hydrogen fire. Furthermore, as the IR3 wavelength of a dedicated hydrogen flame detector measures only in the 2 – 4 μm range relevant to hydrogen flames, it is highly resistant to false alarms (typically seen with other detectors in environments where, for example, welding work is taking place or the presence of carbon dioxide at high temperature).
Conclusion
When it comes to hydrogen, as with broader safety considerations across wider energy transition industries, a failure to adequately consider safety may well lead to setbacks which have the potential to harm the overall goal of reducing carbon emissions and protecting the planet for future generations.
It is therefore crucial that risks are fully understood, both where they are similar to more established sectors such as oil and gas, and where they differ, in order to develop a well thought out safety strategy. By having this in place, risks can be adequately mitigated and therefore investment decisions and planning approvals can be expediated.
Close collaboration between industry and academia is fundamental to the continuous understanding of how hydrogen acts in different situations. Dräger has been working with the University of Aberdeen for several years to support its research into hydrogen and renewable energy, both in supporting its students’ understanding of the safety risks and also by working to advise on safety technology installations for the University’s hydrogen lab. Once complete, the lab will provide a safe environment for hydrogen research. We believe that collaboration of this kind is essential to enable the development of industry-leading uniform safety protocols and recognised safety standards – which will play a critical part in the evolution of good safety in the sector.
