(559d) Biomass Mixing and Segregation in a Fluidized Bed

Fluidized bed technology is useful for combustion, pyrolysis, and gasification of solid fuels such as biomass, which, as an alternative fuel, is important to industry because biomass is a potential alternative to petroleum-based fuels in the United States. There is usually a notable difference in the fluidization behavior between the solid fuel particle and the fluidized bed media (e.g., refractory sand) due to contrasting size, shape, and particle density; these differences can lead to poor solid fuel distribution and diminished performance. The hydrodynamics in a fluidized bed drive gas-solid contact, and thus, have a significant influence on fluidized bed performance. Although fluidized bed hydrodynamics are key parameters in their operation, they are still poorly understood, particularly when the solid fuel component like biomass is significantly different from the fluidized bed media.

This study provides a summary of the visual observations when biomass is mixed with inert fluidized bed material in a 9.5 cm diameter cold-flow fluidized bed. The biomass is composed of ground corncob in three different size ranges (200-300 micron, 500-600 micron, and 800-1000 micron), while the inert bed material is 500-600 micron glass beads. The ground corncob/glass bead mixtures are fluidized at several flow velocities and particle mixing and segregation is observed and documented.