Jack Rabbit III: Hazard Assessment of Factors Affecting Airborne Ammonia Plume Dispersion

The landscape of the U.S. chemical industry is evolving as global demand for ammonia increases, driven by the rising need for fertilizers and its potential use as an alternative energy source. This paper addresses aspects of hazard assessment related to possible release incidents involving ammonia storage tanks, pipelines, and transportation methods. The increased use of ammonia in the U.S. poses heightened risks. One such risk that we describe is related to the transport of ammonia in ships, unloading at ports, and transporting the ammonia inland. A technical survey was conducted, identifying the current market landscape and potential risk areas, with a special emphasis on ports.

With increased transportation and storage of ammonia in a variety of locations year-round, it is essential to minimize the risks of an intentional or accidental release by addressing knowledge gaps in understanding the environmental factors affecting ammonia plume dynamics. Atmospheric dispersion modeling gaps and chemical reactivity concerns in water proximal environments have been identified and experiments initiated in a chamber with dimensions of 6 meters in length, 3 meters in width, and 3 meters in height. The source is a small tank of pressurized liquefied ammonia, which is released as a two-phase jet. These experiments were conducted with various ambient temperatures and relative humidities to cover climate extremes in a static chamber. Ammonia concentration time series were recorded at more than 20 locations in the chamber, with half positioned 0.6 meters from the surface and the other half at a height of 1.8 meters. Videos were also recorded to characterize the initial momentum, impact on the surface, and subsequent diffusion of ammonia released from the source. Additional experiments are being undertaken to study how rain and carbon dioxide may influence the ammonia plume. Further experiments are being planned to design a dynamic test chamber that accounts for typical boundary layer airflow, allowing for ammonia deposition studies on plants and soils.

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