The storage and transport of renewable energy represent major challenges in the transition to a sustainable energy economy. Commonly proposed solutions involve chemical storage of hydrogen in molecules like ammonia, methanol, or liquid organic hydrogen carriers (LOHCs). In such cases, the efficient release of hydrogen from the carrier becomes a critical step. However, reforming ammonia into hydrogen and nitrogen under elevated pressures remains an underexplored topic. Catalytic performance and kinetic data at high pressures and temperatures are absent from the literature, primarily due to the technical challenges in obtaining reliable results and ensuring safe reactor operation. To overcome this gap, a double-walled reactor concept has been developed and constructed for high-pressure ammonia reforming, capable of operating at up to 50 bar and 750 ∘ C . The reactor features axially resolved temperature monitoring and preventive measures have been implemented to avoid unintended catalytic activity on reactor walls, thermocouple surfaces, and dilution materials, ensuring reliable performance data. Reactor safety is maintained by preventing ammonia nitriding of sensitive reactor components. Prior to catalytic measurements, the technical features of the reactor have been systematically validated. A Ni/Al 2 O 3 catalyst was tested at maximum operating conditions, achieving near-full NH X 3 conversion for GHSV values between 10 000 h − 1 and 30 000 h − 1 . The highest recorded H X 2 productivity was 0.52 mmol H X 2 / g cat / s . The mass transfer limitations were thoroughly investigated and excluded for the reported catalytic data. Finally, kinetic parameters for a modified power-law type kinetic model were determined for the first time at 50 bar and temperatures up to 750 ∘ C , determining an apparent activation energy of 170.1 kJ mol − 1 , while the reaction orders for NH X 3 and H X 2 were found to be 0.76 and −1.22, respectively. • New high-pressure reactor for ammonia reforming up to 50 bar and 750 ∘ C. • Double-walled design enables safe operation and suppresses background activity. • Near-full ammonia conversion reached at 10 000 h − 1 GHSV and 50 bar. • Kinetic parameters determined for high-pressure ammonia reforming.
Köseoglu et al. (Mon,) studied this question.