The researcher has developed a catalyst for ammonia synthesis that can respond to the fluctuations in output power of renewable energy sources. In collaboration with researchers of JGC Japan Corporation, they have started ammonia synthesis demonstration tests using the developed catalyst.

Ammonia synthesis verification testing system

Ammonia is of growing interest as a hydrogen carrier and is approaching the stage of practical application. The problems with hydrogen generation by water electrolysis using renewable energy are that low-temperature and low-pressure hydrogen is supplied and the amount of supplied hydrogen fluctuates in time. Therefore, an ammonia synthesis process needs to be developed that makes it possible to use low-temperature and low-pressure hydrogen, whose supplied amount fluctuates.

The developed catalyst, which consists of ruthenium nanoparticles dispersed on a carrier, resolves the issue of the decline in catalytic performance at high pressures due to hydrogen poisoning and maintains high activity at pressures below 10 MPa. Although the operation of the synthesis system using the developed catalyst needs to be controlled to match the fluctuations in the amount of supplied hydrogen, ammonia can be produced stably even when the operating conditions deviated from optimal. The process using the developed catalyst enables synthesis of liquid ammonia on a pilot plant scale at temperatures and pressures lower than those in the conventional Haber–Bosch process. The researchers set up a demonstration system at Fukushima Renewable Energy Institute of AIST and have started ammonia synthesis at various temperatures and pressures.

The researchers will confirm that 20 kg ammonia can be produced per day by the demonstration testing system under operating conditions responding to fluctuations in the hydrogen supply. They will also conduct ammonia synthesis testing using hydrogen produced using renewable energy.