What does "bed" in circulating fluidized bed boiler mean? How to understand the concepts of "circulation" and "fluidization"?

"Bed" is a chemical term, and the "bed" of circulating fluidized bed boiler generally refers to the air distribution plate and the material fluidized in its upper part.

"Circulation" refers to the internal circulation process of the material in the furnace chamber and the external circulation process through the circulation loop.

"Fluidization" means that the material is no longer supported by the air plate, but is supported by the friction of the fluid, and the particles can move freely in the bed.