Abstract
Industrially synthesized ammonia (NH3) is essential to support the world population because approximately 85% of global NH3 production is used as agricultural fertilizer. Recently, NH3 has also been considered as a promising carbon-free H2 carrier for energy storage and transportation. Ammonia’s relatively high boiling point of −33.4 °C (at atmospheric pressure) enables facile liquefaction for compatibility with existing liquid fuel infrastructure.
Further, NH3 has a higher volumetric energy density (12.92–14.4 MJ L–1) than compressed H2 (4.5 MJ L–1) and liquefied H2 (8.49 MJ L–1). Ammonia may be used directly as a fuel in vehicles powered by spark-ignition engines or fuel cells, and ammonia-fueled vehicles are being developed by companies such as Hydrofuel, Hyundai, and Mitsui O.S.K. Lines. Consequently, global NH3 production capacity is expected to expand to 289.83 million tons in 2030 (1.26 times higher production capacity compared to 2018).
