Consequence analysis of aqueous ammonia spills using an improved liquid pool evaporation model

Source term modeling is the key feature in predicting the consequences of releases from hazardous fluids. Aqueous ammonia serves the purpose of a reducing medium and is replacing anhydrous ammonia in most of the Selective catalytic reduction (SCR) units. This newly developed model can estimate the vaporization rate and net mass evaporating into the air from a multicomponent non- ideal chemical spill. The work has been divided into two parts. In the first step a generic, dynamic source term model was developed that can handle multicomponent non-ideal mixtures. The applicability of this improved pool model for aqueous ammonia spills was then checked to aid in the offsite consequence analysis of aqueous ammonia spills. The behavior of the chemical released depends on its various inherent properties, ambient conditions and the spill scenario. The different heat transfer mechanisms associated with the pool will strongly depend on the temperature of the liquid pool system at different times. The model accounts for all the temperature gradients within the contained pool and hence helps us establish better estimation techniques for source terms of chemical mixtures. This research work will help obtain more accurate and reliable liquid evaporation rates that become the critical input for dispersion modeling studies.