Fluidized Beds
“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 the 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.”
Recent Journal Articles
Fluidization of mixtures of two solids differing in density or size
(2325–2333)AIChE Journal 57 #9 (2011)
Formisani, Girimonte and Vivacqua of the Universita della Calabria, Italy, show how the equation that describes the force equilibrium of fluidization can be rewritten in forms that account for the distribution of the components of density- or size segregating mixtures during the transition to the fluidized state. This approach leads to the theoretical expression of uif and uff of either type of system, whose differences of behavior are correctly reproduced by accounting for the voidage reduction typical of beds of particles of different size. The comparison with experimental results at varying mixture composition demonstrates that the equations give a coherent interpretation of the dependence of the fluidization velocity interval of two-solid mixtures on the principal variables of interest. (RDC 8/9/2011)