Ammonia Slip and effect.

Answer

Ammonia slip means unburnt ammonia (NH₃) passing through the engine/combustion system and being discharged with the exhaust gas.

It can occur because ammonia has slow flame speed, high ignition temperature and poor combustion characteristics, especially at low engine loads.

• Toxicity: NH₃ is highly toxic; exhaust release can create a hazardous area for crew and port personnel.
• Environmental pollution: Unburnt ammonia released to atmosphere is harmful and may contribute to nitrogen deposition.
• Odour / personnel exposure: Ammonia can be detected at very low concentration, while higher concentrations become dangerous.
• Reduced fuel efficiency: Unburnt NH₃ means part of the fuel energy has not been utilized.
• After-treatment problems: Excess ammonia through SCR or other exhaust-treatment systems can increase NH₃ emissions.
• Possible deposits/corrosion: Ammonia and associated compounds can create operational problems in exhaust and after-treatment systems.
• Global Warming via N2​O Formation: Slipped NH3​ can convert via atmospheric oxidation into nitrous oxide (N2​O), a greenhouse gas with a Global Warming Potential (GWP) 273 times higher than CO