Accident reconstruction and plume modeling of an unplanned ammonia release

Abstract

This paper describes the study we performed in relation to an accidental release of ammonia at a plant in Luling, Louisiana. Our work involved the understanding of the dynamics of the accident, the evaluation of the emission scenario, the computer modeling of the ammonia plume transported by the wind, and the visualization of our results for the purpose of litigation support and presentation to a non-technical audience. The emission scenario was complicated because of a high-velocity jet release and stormy weather conditions. We used emissions and weather data available at the site, in addition to other local weather data. We also used an EPA-approved model to simulate the transport and dispersion of the ammonia cloud and calculate ground-level concentrations of ammonia over the period of concern (a 2-hour interval). We concluded that maximum hourly concentrations of ammonia, beyond the industrial fenceline in the local community, were around 0.20 ppm, which is far below existing levels of concern. However, our odor modeling calculations showed that short-term concentrations were potentially larger, and may have reached 5 ppm for very short periods. Our estimated concentrations of ammonia were validated by the locations and times of local odor complaints as well as in-situ measurements. Finally, we visualized the plume by applying a simplified version of our MONTECARLO particle model and creating a computer animation of plume concentrations, in order to illustrate the dynamics of the events to a non-technical audience.

Modelling the atmospheric dispersion of ammonia in an industrial area in northern Greece

“…For instance, our results are in close agreement with the estimates obtained by Dore et al (2009) who used the Fine Resolution Atmospheric Multi-pollutant Exchange (FRAME) atmospheric transport model to model releases from a single ammonia source [11]. Similarly, Daly et al (2013), when studying an accidental release of ammonia at a plant in Luling (Louisiana), found that the maximum hourly concentrations were far below the existing levels of concern under stormy weather conditions [12]. Furthermore, Kanwardeep et al (2008) used the short-range dispersion model AERMOD to study the levels of ammonia and concluded that the highest deposition of ammonia at short range occurred under stable conditions, whereas the lowest deposition was found during unstable conditions [13].…”

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“…Air pollution modeling can depict contamination, including an investigation of outflow sources, physical fand substance changes, meteorological cycles, and forecast the human outcomes. 8,14 Air Quality Softwares (AirQ models) is a valuable tool for evaluating the health impacts related with air pollutants. Measuring the impacts on general soundness of openness to air contamination has turned into a basic part in strategy conversation.…”

Numerical Simulation of Air Pollution in Case of Unplanned Ammonia Release

“…Another approach for assessing the zones of chemical contamination is the application of the Gaussian plume model [2,3,[10][11][12][13][14]. The use of the analytical models or Gaussian models allow to calculate quickly zones of chemical contamination.…”