Analysis of biomass gasification in a fluidized bed using CFD-DEM

Computational fluid dynamics coupled with discrete element method (CFD-DEM) was used to numerically study biomass gasification in a three-dimensional fluidized bed. The model includes heat transfer and homogeneous and heterogeneous chemical reactions. The effects of the main operating parameters on the performance of the gasifier were studied in terms of equivalence ratio (ER), ratio of steam mass flow rate to biomass mass flow rate (S/B), and gasification temperature. The simulation results showed that as the ER and S/B increased and the gasification temperature decreased, the mole fractions of methane and carbon monoxide in the product gas decreased. S/B and the gasification temperature have a direct effect on the mole fraction of hydrogen in the product gas. The effect of operating conditions on the carbon conversion efficiency was also investigated. With increasing ER and gasification temperature, the carbon conversion efficiency increased, while with increasing S/ B, the carbon conversion efficiency first increased and then decreased.