Enabling green ammonia as future transport fuel

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Ammonia, a highly hydrogenated molecule, has been identified as an important means to support a transition to hydrogen economy, as it can be used to store and distribute hydrogen easily because of the already existing infrastructure for transport and storage of ammonia. If hydrogen is to be extracted from ammonia at the point of use, the thermo-catalysis of ammonia back to hydrogen requires a high amount of energy. Preferably ammonia is used directly as a carbon-free liquid fuel for combustion engines in power generation, marine vessels and long-haul vehicles where batteries cannot be used due to their low energy density (hence large volume and weight), high cost and long charging times. However, the significantly lower energy density (as measured by calorific value) of ammonia requires much larger fuel storage space and weight to be used. More importantly, the direct application of ammonia in combustion engines suffers from incomplete combustion and poor engine performance due to ammonia's higher ignition energy, higher auto-ignition temperature as well as significantly lower flame speed. In order to address the aforementioned challenges of ammonia and hydrogen for their applications in transport, a new type of liquid ammonia blended with hydrogen will be researched and demonstrated in this project with advanced modelling and experimental techniques. The proposed novel fuel has both ammonia and hydrogen molecules, and will enable (1) immediate and wider use of carbon free ammonia and hydrogen in existing engines, particularly for long haul vehicles, marine vessels and power generators, (2) significantly improved engine performance and lower emissions through increased energy density, faster and complete combustion. Therefore, the developed liquid ammonia blended with hydrogen would enable an immediate, cost-effective and 100% reduction in CO2 emissions to achieve net zero target in long haul transport, shipping, and power generation sectors by and beyond 2050 that will be difficult to achieve with existing technologies in use or in development.