Enabling green ammonia as future transport fuel

氨是一种高度氢化的分子，已被确定为支持向氢经济过渡的重要手段，因为由于现有的氨运输和储存基础设施，它可以很容易地用于储存和分配氢。如果要在使用时从氨中提取氢，氨的热催化还原为氢需要大量的能量。最好将氨直接用作发电、船舶和长途车辆的内燃机的无碳液体燃料，这些地方的电池由于能量密度低(因此体积和重量大)、成本高和充电时间长而无法使用。然而，氨的能量密度(以热值衡量)显著较低，需要使用更大的燃料存储空间和重量。更重要的是，由于氨具有较高的点火能量、较高的自燃温度以及较低的火焰速度，直接在内燃机上使用氨存在燃烧不完全和发动机性能差的问题。为了解决氨和氢在运输中的应用所面临的上述挑战，本项目将利用先进的建模和实验技术来研究和演示一种与氢混合的新型液氨。拟议的新型燃料同时含有氨和氢分子，将使(1)现有发动机，特别是长途车辆、船舶和发电机，立即和更广泛地使用无碳氨和氢，(2)通过提高能量密度、更快和完全的燃烧，显著改善发动机性能和降低排放。因此，开发的液氨与氢气混合将能够立即、具有成本效益地100%减少二氧化碳排放，从而在2050年及以后实现长途运输、航运和发电部门的净零目标，这是现有技术在使用或开发中难以实现的。

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.