fluidization


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fluidization

[‚flü·ə·də′zā·shən]
(chemical engineering)
A roasting process in which finely divided solids are suspended in a rising current of air (or other fluid), producing a fluidized bed; used in the calcination of various minerals, in Fischer-Tropsch synthesis, and in the coal industry.

Fluidization

The processing technique employing a suspension or fluidization of small solid particles in a vertically rising stream of fluid—usually gas—so that fluid and solid come into intimate contact. This is a tool with many applications in the petroleum and chemical process industries. Suspensions of solid particles by vertically rising liquid streams are of lesser interest in modern processing, but have been shown to be of use, particularly in liquid contacting of ion-exchange resins. However, they come in this same classification and their use involves techniques of liquid settling, both free and hindered (sedimentation), classification, and density flotation. See Mechanical classification

The interrelations of hydromechanics, heat transfer, and mass transfer in the gas-fluidized bed involve a very large number of factors. Because of the excellent contacting under these conditions, numerous chemical reactions are also possible—either between solid and gas, two fluidized solids with each other or with the gas, or most important, one or more gases in a mixture with the solid as a catalyst. In the usual case, the practical applications in plants have far outrun the exact understanding of the physical, and often chemical, interplay of variables within the minute ranges of each of the small particles and the surrounding gas phase.

With such excellent opportunities for heat and mass transfer to or from solids and fluids, fluidization has become a major tool in such fields as drying, roasting, and other processes involving chemical decomposition of solid particles by heat. An important application has been in the catalysis of gas reactions, wherein the excellent opportunity of heat transfer and mass transfer between the catalytic surface and the gas stream gives performance unequaled by any other system. See Fluidized-bed combustion, Gas absorption operations, Heat transfer, Unit operations

References in periodicals archive ?
Fluidization is the uncontrolled addition of concentrate to the furnace, and is the result of the dry-charge bin characteristics and the fluid-like character of a bone-dry, finely divided charge.
Grace, "A State-of-the-Art Review of Gas-Solid Turbulent Fluidization," Chem.
The new Forberg II twin-shaft mixer is said to offer very high-speed, high-efficiency mixing using mechanical fluidization.
Minimum fluidization velocity of particle blends can be calculated by the Ergun equation with reasonable accuracy (Bi, 2005).
Typically, these machines use lower blow pressure and higher air volume, and can nearly empty the blow head each cycle, A few manufacturers utilize a process called "extruding", which differs from fluidization.
The Aero-Mechanical Conveyor, presented in the company's brochure, utilizes a fluidization process to quickly convey powder with reduced degradation.
Additionally full tests include small scale and bench testing to determine material properties such as: abrasion, bulk density, angle of slide, angle of repose, gravity flow, moisture content, terminal velocity, pick-up velocity, sieve analysis, angle of internal friction and fluidization.
In the core shooting process, a blow head filled with sand is pressurized with air, leading to the fluidization of the sand which results in a "fluid" consisting of an air/sand/binder mixture.
Finely dispersed bubbles generated by the sparging system are carried by the fluidization water into the fluidized bed where they are efficiently forced into contact with the densely packed particles.
2014 accessibility and fluidization of traffic to the industrial area of Ploiesti West and the industrial platform firs (overpass over the railway Bucharest - Brasov), COD SMIS: 48114.
Chen and Yuan [11] simulated the SSP of low molecular weight micro-beads in a continuous gas fluidization bed with multiple stages.