Analysis of Ammonia Discharged from Ammonia Fuel Supply System During Ammonia Depressurization Process According to Recovery Pressure

Abstract The dual-fuel engines secure the stability of the engine and the fuel supply system through a purging process with nitrogen in situations such as dual-fuel stop or shutdown. However, since ammonia has fatal toxicity depending on its concentration and exposure time, discharged flow analysis of the ammonia fuel supply system is required. In this study, the flow characteristics of ammonia and nitrogen mixture discharged from the fuel supply system were analyzed by simulating the ammonia purging process with Aspen HYSYS. The fuel supply system was modeled for the ammonia engine under development from MAN ES, and some parts of fuel supply system were estimated. Purged ammonia was mixed with water in the ammonia catch system except for the amount that can be recovered. The investigation reveals that as the recovery pressure increases, the amount of recovered ammonia also increases. Simultaneously, the amount of ammonia discharged into the atmosphere through the water tank decreases. The results showcase a positive correlation between recovery pressure and the efficiency of ammonia recovery during the depressurization process. These findings contribute valuable insights for designing effective systems that prioritize the recovery and treatment of discharged ammonia, mitigating potential safety concerns.