Assessing the inherent atmospheric environmental friendliness of chemical process routes: An unsteady state distribution approach for a catastrophic release

The inherent environmental friendliness of a chemical process plant is assessed quantitatively based on its short-term atmospheric impacts due to a catastrophic release of the entire inventory of chemicals. In a catastrophic release of chemicals the environment into which the chemical is distributed will change with time. Therefore, it is important to account for these model environment changes in the chemical distribution method used when estimating short-term impacts.This paper proposes a method that uses the dispersion characteristics of the chemical in the atmospheric environment to estimate the model environmental volumes. Its distribution within this environment, between the different compartments such as air, soil or water is considered to estimate the predicted environmental concentrations (PEC). These values are then used in an index called the atmospheric hazard index (AHI) which assesses the inherent environmental friendliness of the chemical process plant. These AHI results are compared with those estimated by a method that uses the unit world model environment to estimate PEC values.