Humidity Tolerant Hydrogen-oxygen Recombination Catalysts for Hydrogen Safety Applications

Catalytic hydrogen-oxygen recombination is a non-traditional method to limit hydrogen accumulation and prevent combustion in the hydrogen industry. Outside of conventional use in the nuclear power industry, this hydrogen safety technology can be applied when traditional hydrogen mitigation methods (i.e., active and natural ventilation) are not appropriate or when a back-up system is required. In many of these cases it is desirable for hydrogen to be removed without the use of power or other services, which makes catalytic hydrogen recombination attractive. Instances where catalytic recombination of hydrogen can be utilized as a stand-alone or back-up measure to prevent hydrogen accumulation include radioactive waste storage (hydrogen generated from water radiolysis or material corrosion), battery rooms, hydrogen-cooled generators, hydrogen equipment enclosures, etc.
Water tolerant hydrogen-oxygen recombiner catalysts for non-nuclear applications have been developed at Canadian Nuclear Laboratories (CNL) through a program in which catalyst materials were selected, prepared and initially tested in a spinning-basket type reactor to benchmark the catalyst’s performance with respect to hydrogen recombination in dry and humid conditions. Catalysts demonstrating high activity for hydrogen recombination were then selected and tested in trickle-bed and gas phase recombiner systems to determine their performance in more typical deployment conditions. Future plans include testing of selected catalysts after exposure to specific poisons to determine the catalysts’ tolerance for such poisons.