Airfluidization

Airfluidization is a process where a bed of solid particles is suspended in an upward flowing stream of air. When the velocity of the air reaches a critical point, known as the minimum fluidization velocity, the drag force exerted by the air on the particles becomes equal to the weight of the particles. At this point, the entire bed of particles behaves like a fluid, exhibiting properties such as leveling, bubbling, and exhibiting a hydrostatic pressure.

The phenomenon is widely used in various industrial applications due to its ability to facilitate efficient mixing, heat transfer, and mass transfer between the solid particles and the fluidizing medium. Common applications include drying of granular materials, catalytic cracking in petroleum refining, combustion of solid fuels in fluidized bed combustors, and pharmaceutical granulation. The design of a fluidized bed system involves careful consideration of particle size distribution, particle density, air flow rate, and the geometry of the vessel to achieve stable and efficient fluidization. Factors like particle agglomeration and erosion can be challenges that require specific engineering solutions.