Disaster Simulation in Chemical Plants Considering Diffusion of Gas and Heat Radiation from Tank Fire

摘要

We have developed a computer simulation program in order to make clear effects of storage?ˉs outflow, evaporation, diffusion of gas, tank fire and extinguishments in chemical plants. The trigger of disaster is the outflow of the storage subjects in a tank. The occurrence of the outflow is classified into three modes: little, middle and large leakage. In case of middle leakage mode, we have developed the simulation program for the concentration of gas considering combination of the flash evaporation and the evaporation by temperature of ground. When the tank fire occurs in a plant, the heat radiation from flame to affected tanks is calculated with Monte Carlo method in order to consider the climate, the location and the shape of tanks. The spread of tank fire is judged by the increase of temperature of the heat affected tank. As the prevention of the disaster progress, the effect of extinguishment with sprinklers is also taken into account. Furthermore, GIS (Geographical Information Systems) is very effective, because it is very easy to get the situation immediately of the occurrence of disaster for a plant. The disaster simulation is connected with GIS, and the dangerous zone caused by tank fire can be estimated. When the tank fire occurs in an actual plant model in Kawasaki area in Japan, the dangerous heat affected zone for a human body and the increase of inner temperature of heat affected tanks can be indicated on digital map by using the proposed system.