(57p) Review and Analyze the Effects of Parameters for H2s Gas Mixture Dispersion Models: Degadis and CFD Models

Due to the increasing demands of energy, natural gas explorers and developers are interested in exploring sour gas fields, which have a high concentration of hydrogen sulfide (H₂S). Because H₂S is highly corrosive and could reduce the heating values of natural gas, H₂S needs to be removed from natural gas before transfer. Then the removed H₂S gas will be converted to sulfide as the products in the Claus process. The H₂S mixture (e.g., H₂S and CO₂) may cause corrosion to pipelines and thus, could lead to H₂S gas mixture release.

H₂S mixture behaves as a heavy gas, which travels down to the ground causing harm to the local population and the environment. In this paper, the DEnse GAs DISpersion (DEGADIS) model and the Computational Fluid Dynamics (CFD) model (e.g., ANSYS Fluent) are implemented for the H₂S mixture simulation, and assumptions in the models are also studied. The effects of topography and meteorological parameters such as atmospheric temperature, wind speed, and humidity are investigated. Finally, the simulation results from the DEGADIS model and the CFD model for flat terrain with constant wind velocity are compared.

The simulation results show that the DEGADIS model, which is suitable for flat terrain and constant wind conditions, can be applied to simple terrain geography and stable atmospheric conditions. Whereas the CFD model, which considers unsteady wind speed and turbulence near the obstacles, can be utilized for complex topography. The series of simulation results can provide guidance for the risk assessment of H₂S mixture releases under different topographies and meteorological conditions.