CFD MODELING OF BINARY MIXTURE HYDRODYNAMICS IN GAS-SOLID PARTICLE FLUIDIZED BED REACTOR SYSTEM

The objective of this research was to compare the effect of a binary mixture between coal, including 500, 700 and 1000-micron size, and sand, 180-micron size, on the mixing behavior in a fluidized bed system. In addition, suitable computational fluid dynamics drag models were explored, including an EMMS model, Gidaspow model and Wen & Yu model. The simulation results were compared for correctness with real plant information. The EMMS model matched well with the obtained data, This is because the employed model considers the particle cluster effect. The EMMS drag model was then used for further computational fluid dynamics simulation. The levels of mixing between sand and coal were predicted by turbulent dispersion coefficient. These coefficients of coal particle were exhibited in axial and radial direction. The highest turbulent dispersion coefficients were found in the mixture with 500 and 1000 micron coal size for radial and axial directions, respectively. The low axial turbulent dispersion coefficient and high radial turbulent dispersion coefficient were preferred for good hydrodynamics behavior.