Experiment and computational fluid dynamics investigation of biochar elutriation in fluidized bed

Abstract

In fluidized bed biomass fast pyrolysis, the biomass is converted to biochar and elutriated. The elutriation rate is a key parameter in reactor designs and operations. This research presents a video‐based continuous measurement of biochar elutriation rate in a fluidized bed with sands and biomass as bed materials. The fluidized bed is simulated with the computational fluid dynamics—coarse‐grained discrete element method (CFD‐CGDEM) in MFiX. The fluidization behavior of nonspherical sands can be more accurately captured when a rolling friction model is used. The predicted elutriation rate is close to the experimental measurement when the particle size distributions are considered and the filtered drag with a shape correction is used. These results validated the accuracy of the MFiX‐based CFD framework for the prediction of biochar elutriations in the fluidized bed biomass fast pyrolysis reactor.

Simulation of Crude Oil to Chemicals Based on Mesoscale Filtered Drag Subgrid Model

“…The volume fraction gradient-modified drag model used to simulate the fast fluidized beds, and the axial solid holdups of the simulated fast fluidized beds were in agreement with that of the experiment. The drag model of the nonspherical particle also was studied , by correlating average solid volume fraction and average Reynolds number. For microcubic particles and the whole fluid region, the related macroparameters of the average solid volume fraction and average Reynolds number influenced the fluid flow state.…”