What is a fluidized bed? Here are some definitions.
Noun
An industrial unit process in which a quantity of a solid particulate substance is caused to float in a stream of a fluid (usually air or other gas) in order to create conditions in which many chemical, combustion and drying reactions take place efficiently.
A reactorvessel or other piece of equipment in which a substance is maintained in the fluidized state. In this context, often used attributively.