Investigation of the oxidation zone in a biomass two-stage downdraft gasifier
Résumé
The partial combustion in a two-stage downdraft gasifier is critical for the process optimisation. Flame temperature and residence time of gas in the hot zone are indeed determining for tar cracking, the major issue in gasification. This paper presents a CFD model of the oxidation zone. Chemical reactions, including tar cracking, are treated by the ''EDC'' model (homogeneous reactions). Fluid flows are turbulent and simulated by the k-epsilon RNG turbulence model. The validation of the model is done with the DTU 100 kW two-stage gasifier. Results fit satisfactory the data, regarding the temperature profile.