Modeling and design validation of fluidized bed reactors for co-gasification of coal and biomass to study hydrodynamics and conversion

Abstract

The gasifier was designed with reaction chamber of 65mm diameter and 500 mm height. The study of gas-solid hydrodynamics is essential in designing of fluidized bed gasifier. Drag force plays a critical role in modeling fluidization behavior for gas-solid flow. This paper aims to study the effect of drag force on the fluidization parameter for the presently designed gasifier using CFD approach. The Eulerian-Eulerian model, coupled with different drag models was employed for this purpose. Time-averaged solid volume fraction, granular temperature, axial velocity of the solid particle in a lateral direction, and a central axis of the reactor were examined for different drag models like Syamlal O�Brien, Gidaspow, Mckeen and Representative unit cell. Effects of laminar and turbulent models on flow behavior were also studied. The study concluded that the McKeen model shows a relatively flat profile while estimating solid volume fraction while the RUC model overestimated the axial velocity of particles. There was relatively no change in flow behavior for the laminar and turbulent model while predicting the axial velocity of the solid particle in the lateral direction. The axial velocity of particles at a different packing factor was studied and showed no such observable difference in predicting hydrodynamics flow behavior. � 2019 ETA-Florence Renewable Energies.