AMmoniA Zero Emission abateMENT (AMAZEMENT)

Despite being the most efficient mode of transporting cargo, shipping globally has a significant carbon footprint. The sector today represents approximately 3% of global CO2 emissions. The impact of other harmful emissions from shipping, such as particulate matter and sulfur oxides (which are detrimental for human lungs), is believed to be even greater. Authorities are seeking to address the issue through various means. In 2020 the International Maritime Organization (IMO) introduced rules to cap sulfur emissions and is now aiming to further reduce CO2 emissions. Decarbonization of shipping will not be instantaneous nor easy. The global fleet currently almost completely relies on fossil fuels. That said, there are new fuels and technologies emerging in the sector. For example, ships are being electrified, sails are making a comeback as an assisting means of propulsion, and new promising fuels such as hydrogen, methanol and ammonia (NH3) are being tested. Ammonia made with renewable energy is a very promising fuel for several shipping segments. It is carbon free, a widely traded commodity, and has a high energy density. Ammonia will however generate some emissions like all other promising fuels when combusted. To tackle this, the AMAZEMENT (AMmoniA Zero Emission abateMENT) project focuses on developing technological solutions to minimize such emissions from the use of ammonia as a maritime fuel. This will be achieved by targeting the following emissions that are produced by an engine burning ammonia: - Un-combusted ammonia (NH3) – Risk to human health - Nitrogen oxides (NOx) – Contributes to acid rain - Nitrous oxide (N2O) – Greenhouse gas, 300 times more harmful than CO2 The technology will convert these emissions found in the engines exhaust gas into harmless nitrogen gas and water, allowing the cleaned gas to be safely released into the air by the ship. This process is essential for the use of ammonia as an environmentally friendly marine fuel.

Several promising materials were found which can potentially be used to abate harmful biproducts (NOX, NH3 and N2O) emitted by the use of ammonia as a marine fuel. If required, these abatement materials can assist in lowering global green-house gas emissions via ensuring the adaption of ammonia as a green marine fuel and removal of any subsequential emissions. The project was able to identify, synthesize and test various materials capable of low-temperature nitrous oxide (N2O) abatement. The materials tested are of low cost compared to potential alternatives considered however, they showed ‘low’ efficiency in the exhaust gas temperature range of interest for ammonia fueled engines. Low conversion efficiency can be combatted by adjusting the amount of material utilized, according to commercial factors and regulatory limits (not yet defined for N2O) or via further research and development targeted at improving the efficinecy in this low-temperature range through modification of the material and synthesis method. The materials tested also exhibited unexpected side reactions with other components present in the expected exhaust gas from an ammonia fueled engine. These side reactions could be potentially exploited or limited through further research and development of the materials tested. It is foreseen based on the results that with further research the N2O abatement materials researched could potentially be utilized as part of an overall abatement system for ammonia fuelled engines in future. The project was also able to identify, synthesize and test various materials capable of high efficiency low-temperature ammonia oxidation (abatement), with low selectivity to nitrous oxide (N2O) generation. The results showed a number of promising candidates. Existing marine industry ammonia oxidation catalysts have not been concerned with low selectivity to N2O when oxidizing ammonia. However, this is essential when considering the correct method for abating ammonia slip from ammonia engines, as any N2O generated will impact the vessels total emissions impact (N2O has a global warming potential 300x CO2). A low cost, low N2O selectivity ammonia oxidation catalyst would offer strong advantages over existing products on the market and assist in enabling the use of ammonia as a clean marine fuel and reducing global emissions. Based on the results from the tested N2O and NH3 abatement materials, application methods for the use of the materials were invented based on specific engine type and placement. These methods of using the materials could be commercialized and used as part of an overall abatement system for ammonia fuelled engines to reduce the overall size and cost for the abatement system.

The AMAZEMENT (AMmoniA Zero Emission abateMENT) project aims to develop a new abatement system for the removal of nitrous oxide (N2O), nitrogen oxides (NOX) and ammonia slip (NH3) from the exhaust gas of an ammonia fuelled engine used for maritime propulsion and power generation. It is comprised of fundamental changes to the abatement system technology used for removal of atmospheric pollutants from marine engine exhaust gas. The project will enable the use of ammonia as a carbon free marine fuel with zero or extremely low pollutant emissions and it will demonstrate the multi-stage abatement system capable of removing the exhaust gas’s polluting components. Stricter emissions regulations are an imminent challenge for the maritime industry. To mitigate the environmental threat imposed by greenhouse gases (GHG) and other pollutants, the International Maritime Organisation (IMO) has set the target of a reduction in CO2 emissions by 40% by 2030 and an overall reduction in greenhouse gas (GHG) emissions by 2050. To achieve zero emission vessel operation shipowners are looking to ammonia as a fuel due to its high energy density, existing and mature production and storage, and ability to be produced from renewable energy. When combusted in-engine, the exhaust gas will contain nitrogen oxides (NOX), un-combusted ammonia (NH3), and nitrous oxide (N2O). The most challenging component to abate is N2O, a potent ozone depleting GHG and it has approximately 300 times higher global warming potential than CO2. Land-based methods utilise specialised catalysts and the high temperature of the gas for efficient abatement. Ammonia fuelled engine exhaust gas will be significantly lower resulting in zero to very-low conversion using existing methods. The AMAZEMENT project aims to develop a N2O catalyst with a high conversion rate at sufficiently low temperatures as part of a system treating N2O, NOX and NH3 present in the exhaust gas from an ammonia engine.