Modeling of Ammonia Emission in the Petrochemical Industry

Ammonia is a commonly used chemical in the process industries. Chemical leakage is one of the main problems threatening the staff, facilities, and the environment in the process industries. The aim of this study was to model the emission of ammonia and its consequences in the petrochemical industry. In this study, three accident scenarios of the most probable ones were chosen, including toxic vapor cloud, jet fire, and boiling liquid expanding vapor explosion (BLEVE). Then, the scenario modeling was done using areal locations of hazardous atmospheres (ALOHA) software. In the first scenario, the total released ammonia is 81,316 kg. The concentration of ammonia toxic vapor is greater than 1,100 ppm (AEGL-3 region) at a distance of 1 km, which might cause death in 60 seconds. The overpressure never exceeds 3.5 psi; thus, there is no possibility of serious injury or destruction of buildings. In the third scenario, the thermal radiation of BLEVE is greater than 10 kW/m2 at a distance of 376 m, which is potentially lethal within 60 seconds. One of the main risks in petrochemical companies is the leakage of ammonia. The toxicity of ammonia is the most significant threat to people. The overpressure of vapor cloud explosion does not cause serious injury or of building destruction. The thermal radiation from jet fire and fireball has no effect on the city while it may cause death to the staff within 60 seconds. Thus, safety precautions should be considered to prevent the consequences of leakage accidents.