What is "fluidized bed"

n. 1 An industrial http://en.wikipedia.org/wiki/unit%20process 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 reaction take place efficiently. 2 A reactor vessel or other piece of equipment in which a substance is maintained in the fluidized state. In this context, often used attributively.

A fluidized bed is formed when a quantity of a solid particulate substance (usually present in a holding vessel) is placed under appropriate conditions to cause a solid/fluid mixture to behave as a fluid. This is usually achieved by the introduction of pressurized fluid through the particulate medium. This results in the medium then having many properties and characteristics of normal fluids, such as the ability to free-flow under gravity, or to be pumped using fluid type technologies.

The resulting phenomenon is called fluidization. Fluidized beds are used for several purposes, such as fluidized bed reactors (types of chemical reactors), fluid catalytic cracking, fluidized bed combustion, heat or mass transfer or interface modification, such as applying a coating onto solid items. This technique is also becoming more common in aquaculture for the production of shellfish in integrated multi-trophic aquaculture systems.

Articles on Fluidized bed include:

• Fluidized bed
• Fluidized bed combustion
• Fluidized bed dryer
• Fluidized bed reactor
• Coffee roasting using a fluidized bed