Fluidization of biomass and inert particle mixtures in a pseudo 2D pressured fluidized bed

Biomass is a crucial renewable energy source, but its handling in fluidized beds for thermochemical conversion presents significant challenges. This study addresses the limited understanding of biomass particle hydrodynamics by investigating a pseudo-2D pressurized fluidized bed using digital image analysis techniques. The effects of biomass mass fraction in binary mixtures with inert particles and operating pressure on minimum and final fluidization velocities, mixing/segregation characteristics, and bubbling behaviors were comprehensively examined. Results indicated that the minimum and final fluidization velocities of binary mixtures increase with biomass mass fraction and decrease as pressure rises from ambient condition to 0.6 MPa. The mixing index decreases with increasing biomass loading, with a critical mass fraction of 25 % beyond which fluidization deteriorates or fails due to particle channeling. Higher operating pressure improves biomass fluidization but negatively affects the mixing degree between biomass and inert particles. This adverse effect is attributed to reduced bubble size and the corresponding decrease in the driving force necessary for particle mixing. These findings enhance the understanding of biomass particle dynamics and significantly contribute to the advancement of efficient and sustainable biomass energy conversion processes.