Emissions Countermeasures for Marine Ammonia Engines

This technical report presents findings on emissions countermeasures for low-speed two-stroke marine ammonia engines, focusing on the challenges and solutions associated with ammonia as a marine fuel. The paper discusses the results of the world's first full-scale test of an ammonia engine conducted by Mitsui E&S and MAN Energy Solutions in mid-2024. It outlines the emissions of nitrogen oxides (NOx), unburned ammonia slip, and nitrous oxide (N2O), which are critical factors in assessing the environmental impact of ammonia engines. The report details the selection of the MAN HP-SCR technology as the optimal solution for reducing emissions and by-products. It also describes the experimental setup for evaluating ammonia slip catalysts (ASC) and the performance tests conducted to identify suitable catalysts for selective catalytic reduction (SCR) systems. The study emphasizes the importance of optimizing combustion conditions and catalyst selection to mitigate emissions effectively. Overall, the report contributes to the understanding of ammonia engine emissions and potential mitigation strategies.