Ann de Beer (left), with Keenan Naidoo.
The SAIMC Johannesburg Branch technical event for August was hosted by Swagelok, with the guest speaker being Keenan Naidoo. Keenan is a field engineer whose expertise shone through in his wonderful presentation. The topic was ‘Clean Energy: Hydrogen Basics’.
In this rapidly developing world, with its constant pressure to reduce carbon emissions, there has been a strong move towards developing clean energy. One promising source of alternative energy is hydrogen. This is present in natural resources such as water and hydrocarbons like methane. Two commonly mentioned ways of extracting hydrogen are steam methane reforming and electrolysis.
The production of hydrogen is often categorised into colours, which describe the process and the byproducts. Grey hydrogen is the standard, but the process produces substantial amounts of carbon emissions.
Blue hydrogen is the output of the steam methane reforming process, and converts natural gas into hydrogen, with carbon dioxide as a byproduct. The carbon dioxide is then captured and stored underground. This process is cheaper than green hydrogen and less destructive to the environment than grey hydrogen. However, it has the potential to make environmental issues much worse should there be a release of carbon dioxide to the atmosphere.
Green hydrogen is the latest development, and the technology is the subject of extensive research and development. It is produced through the electrolysis of water using renewable energy sources such as wind and solar power. The process splits water molecules into hydrogen and oxygen, resulting in a clean fuel that produces only water vapour on combustion.
Once the hydrogen gas is produced what do we do with it? As a gas it has a low density and takes up a lot of space, but there are solutions. By increasing the storage pressure it can be compressed to reduce the space it occupies, or it can be liquefied by cooling. Each of these methods has its own requirements. Because of its properties, caution also needs to be exercised when handling hydrogen. For example when fluid systems are being designed, careful consideration should be given to the selection of materials and elastomers as hydrogen interacts with these materials uniquely.
Green hydrogen is already being utilised in applications worldwide, including vehicles, trucks, forklifts and generators. These generate their own electricity using a fuel cell rather than relying on a built-in battery as in electric cars. The fuel cell converts green hydrogen from a tank in the car and oxygen from the air into electrical energy through electrolysis. This process produces only heat and water vapor, with no emissions. This is a big win as current internal combustion engines produce a whole range of harmful emissions.
Green hydrogen is definitely on track to being better understood and shows great promise as a fuel for the future.
The Johannesburg team would like to thank Swagelok for the insightful presentation.
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