Experimental Releases of Liquid Hydrogen

If the hydrogen economy is to progress, more hydrogen refuelling stations are required. In the short term, in the absence of a hydrogen distribution network, the most likely means of supplying the refuelling stations will be by liquid hydrogen road tanker. This development will clearly increase the number of tanker offloading operations significantly and these may need to be performed in more challenging environments with close proximity to the general public. The work described in this paper was commissioned in order to determine the hazards associated with liquid hydrogen spills onto the ground at rates typical for a tanker hose failure during offloading.
Experiments have been performed to investigate spills of liquid hydrogen at a rate of 60 litres per minute. Measurements were made on both unignited and ignited releases.
These include:

• Concentration of hydrogen in air, thermal gradient in the concrete substrate, liquid pool formation, and temperatures within the pool
• Flame velocity within the cloud, thermal radiation, IR and visible spectrum video records.
• Sound pressure measurements
• An estimation of the extent of the flammable cloud was made from visual observation, video, IR camera footage and use of a variable position ignition source.