Study on the Harm Effect of Liquid Hydrogen Release by Consequence Modeling

In this paper, the accidental release of hydrogen from cryogenic liquid storage tank and the subsequent consequences are studied including hydrogen cold cloud, fire ball, jet fire, flash fire, and vapor cloud explosion. The cold effect, thermal effects and explosion overpressures from the above consequences are evaluated using IGC and TNO harm criteria. Results show that for instantaneous releases of liquid hydrogen, the sequence of harm effect distances is that vapor cloud explosion>flash fire>cold cloud> fireball. For continuous releases of liquid hydrogen, the sequence of harm effect distances is that vapor cloud explosion>jet fire>flash fire>cold cloud. The vapor cloud explosion is the leading consequence of both instantaneous and continuous releases and may be used for the determination of safety distances of a liquid hydrogen tank. Besides, the harm effect distances of liquid hydrogen tank are compared with those of compressed hydrogen storages with equivalent mass. Results show that the liquid hydrogen storage may be safer than 70MPa gaseous storage in case of leak scenario but may be more dangerous than 70MPa storage in case of catastrophic rupture. It is difficult to tell which storage is safer from a consequence perspective. Further investigation need to be made from a standpoint of risk, which combined both consequences and the likelihood of scenarios.