Modelling of Biomass Catalytic Pyrolysis: Mixing/Segregation of Biomass and Catalyst in Bubbling Fluidized Beds

Modelling work is carried out to investigate the mixing-segregation phenomena of binary mixtures in biomass catalytic pyrolysis fluidized bed reactors with Eulerian approach. Solid particles of different sizes or densities are treated as two continuum phases individually using Kinetic Theory of Granular Flow (KTGF) while the interactions between different phases are considered by different drag functions. The mixing processes and the degree of solid mixing during fluidization are examined and quantified by mixing index. The model predicts the similar trends with the documented experiment while the results show that the mixing-segregation phenomena are more pronounced in the case of different solid densities whereas the segregation is not obvious for solids with different sizes.