[ oxygen ]
Designing for oxygen-enriched environment found in electrolysers
Whilst hydrogen electrolysers are built to supply high-purity hydrogen, they also produce oxygen by splitting water into its constituent components. Due to the chemical properties of oxygen, special care must be taken when designing, constructing, and operating the oxygen side of an electrolyser plant to ensure the safety of personnel and equipment.
By James Gladstone, Principal Hydrogen Development Engineer, Parker Hannifin – Hydraulic & Industrial Process Filtration EMEA
Introduction
Oxygen is a highly reactive non-metallic element that readily combines with many other elements to form oxides through oxidation reactions. Fire is simply the rapid oxidation of a material in an exothermic combustion process, releasing heat, light, and various reaction products.
Oxygen makes up 20.9 % of Earth’ s atmosphere and most commonly exists as an O 2 molecule. It is a pale blue gas( a colour more noticeable in its liquefied state, as shown in Figure 1), odourless, and tasteless at room temperature. While it is well understood that oxygen is essential for combustion, the concentration of oxygen available can dramatically influence the cause, rate, intensity, and range of‘ fuels’ capable of sustaining a fire.
The fire triangle
The fire triangle is a simple model used to understand the essential ingredients for most fires. It illustrates the three key components required for a fire to ignite and sustain itself.
Heat This component of the triangle provides the energy required for a material to reach its ignition point. It can come from something as obvious as a spark or as subtle as a small piece of debris impinging on a surface within a pipe. Under the right circumstances, both examples could be sufficient to initiate a fire.
Fuel Whilst it is obvious to most what may constitute a fuel under normal atmospheric conditions
Oxygen produced by an electrolyser is almost 100 % pure. In such an environment, even materials generally considered stable can become reactive, posing significant risks. Substances that do not typically ignite under normal atmospheric conditions can burn violently – or even explode – when exposed to high-purity oxygen. It is therefore critical to design systems that can operate safely in oxygen-enriched environments, as oxygen fire events are often catastrophic.
Fig. 1. Liquid oxygen at – 83 ° C
42 Hydrogen Tech World | Issue 21 | April 2025