Experimental Characterization of the Operational Behavior of a Catalytic Recombiner for Hydrogen Mitigation

One of the significant safety concerns in large-scale storage and transportation of liquefied (cryogenic) hydrogen (LH2) is the formation of flammable hydrogen/air mixtures after leakages during storage or transportation. Especially in maritime transportation hydrogen accumulations could occur within large and congested geometries. The installation of passive auto-catalytic recombiners (PARs) is a suitable mitigation measure for local areas where venting is insufficient or even impossible. Numerical models describing the operational behavior of PARs are required to allow for optimizing the location and assessing the efficiency of the mitigation measure. In the present study, the operational behavior of a PAR with a compact design has been experimentally investigated. In order to obtain data for model validation, an experimental program has been performed in the REKO-4 facility, a 5.5 m³ vessel. The test procedure includes two phases, steady-state and dynamic. The results provide insights into the hydrogen recombination rates and catalyst temperatures under different boundary conditions.