Releases of unignited liquid hydrogen
In the long term the key to the development of a hydrogen economy is a full infrastructure to support it, which includes means for the delivery and storage of hydrogen at the point of use, eg at hydrogen refuelling stations for vehicles. As an interim measure to allow the development of refuelling stations and rapid implementation of hydrogen distribution to them, liquid hydrogen is considered the most efficient and cost effective means for transport and storage.
The Health and Safety Executive (HSE) have commissioned the Health and Safety Laboratory (HSL) to identify and address issues relating to bulk liquid hydrogen transport and storage and update/develop guidance for such facilities. The second phase of the project involved experiments on unignited and ignited releases of liquid hydrogen (HSE RR987) and computational modelling of the unignited releases (HSE RR985). This position paper details the experiments performed to investigate spills of unignited liquid hydrogen at a rate of 60 litres per minute. Concentration of hydrogen in air, thermal gradient in the concrete substrate, liquid pool formation and temperatures within the pool were measured and assessed. The results of the experimentation will inform the wider hydrogen community and contribute to the development of more robust modelling tools. The results will also help to update and develop guidance for codes and standards.
This report and the work it describes were funded by the Health and Safety Executive. Its contents, including any opinions and/or conclusions expressed, are those of the author alone and do not necessarily reflect HSE policy.