(188d) Study of Impacts of Air Velocity, Ambient Temperature and Terrain on Chemical Diffusion in Unplanned Release

Air pollution is now a burning question for the wellbeing and even existence of human in today’s world. Chemical industries contribute about 52% to it among all potential sources of air pollution. Any unplanned/accidental release of chemical species can lead to serious loss, injury or even life risk to the community along with contributing to the general air pollution. To ensure a greener environment, unplanned release of air pollutants from industrial process higher than permissible limit must be monitored for public health and safety. A mathematical simulation can provide better understanding over a certain chemicals’ diffusion trends in different scenarios and provide guidelines to a proper planning for reduction of pollution along with right decision making on emergency response and rescue action in case of any dire incident of chemical release.

A finite element analysis model of chemical diffusion from chemical storage leakage has been developed using COMSOL Multiphysics®. In this model, the transport of released chemical through air is driven by both diffusion and convection. Concentration profiles and histories of released chemical were calculated using the Fick’s 2^nd law of diffusion and convection by velocity field of air. Ambient air velocity field is calculated over time using incompressible form of the Navier-Stokes and continuity equations. Physical and thermodynamic properties of the chemical species at different temperature, pressure and composition reported in literatures were used in this mode. Concentration profiles and histories of pollutant species were calculated in different scenarios including: i) without air flow, ii) with air flow at different speed and direction, iii) with obstacles in terrain. The calculated results are analyzed for impacts of terrain, air velocity, and air temperature on the propagation of chemical species with time for an unplanned release situation.