A Reduced Combustion Mechanism for the Simulation of Flaring

Flare is widely used in energy and petrochemical industries to burn out unwanted combustible gases. The detailed combustion mechanisms are too complicated for the speciation study of flaring events with Computational Fluid Dynamics. In addition, the more rigorous ANSYS FLUENT Eddy-Dissipation Concept (EDC) model, which describes turbulence-chemistry interaction, can handle a maximum of only 50 species. To alleviate this computational difficulty, a less than 50 species reduced mechanism is needed. In order to predict the generation of soot and VOCs during the combustion of C1-C4 hydrocarbons accurately and efficiently, a reduced combustion mechanism was generated, based on the detail mechanism in the literature. This approach consists of the generation of skeletal mechanisms using directed relation graph with specified accuracy requirement. The subsequent generation of reduced mechanisms uses computational singular perturbation based on the assumption of quasi-steady-state species. The reduced mechanism was further validated successfully against experimental performance indicators like ignition delay time and adiabatic flame temperature using CHEMKIN. This Reduced mechanism can be used in ANSYS Fluent to predict the emissions and DRE, CE of hydrocarbon flares.