Circulating fluidized bed

Circulating fluidized bed is to suspend a large number of solid particles in the moving fluid, so that the particles have certain apparent characteristics of the fluid. This fluid-solid contact state is called solid fluidization. Namely circulating fluidized bed.

The circulating fluidized bed is fluidized when the gas velocity is greater than the free sedimentation velocity of the particles. The particles are carried out by the gas flow. After the gas is separated from the solid, the solid is circulated back to the fluidized bed formed by the bed. It has many applications in industry. For example, it is used in catalytic cracking. The catalyst is fluidized and transported by heavy oil vapor in the riser and reacts at the same time. The catalyst deactivated at the top of the riser is separated from the oil and gas and then enters another fluidized reactor (regenerator), fluidized by air and regenerated. The regenerated catalyst is recycled back to the riser to form a catalytic cracking reactor of a circulating fluidized bed.