Toxic Gas Dispersion Modelling over Complex Terrains

Accidental toxic gas leakage coming with large exploitation and production activities in the west mountainous area of China is calling for a precise environmental risk analysis method about the leakage and dispersion consequences over complex terrains. However, most studies use simplified models deal with flat terrain scenarios and cannot predict such complex phenomena. This article systematically presents a CFD based method for modelling toxic gas dispersion over complex terrain. First, use GIS data to generate CFD computation grid for complex terrain. Then, a three-step simulation strategy contains ambient wind farm construction, toxic gas leakage and dispersion has been presented. A case study of high sulfide natural gas accidental leakage and dispersion over a mountainous area of 7.2×4.5 km2 has also been carried out. The research demonstrates that the CFD approach of modelling toxic gas dispersion over complex terrain can predict dispersion and toxic consequences quantitatively. It can be widely used in problems concerned with environmental risk analysis over complex terrains.