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.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

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

McGraw-Hill Concise Encyclopedia of Engineering. © 2002 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Moreover, based on direct visual observation, and accounting for distributor effects and gulf streaming, binary expansions on combining two monocomponents at a given liquid fluidization velocity have not been reported in any literature examined by the present authors.
* the temperature of fluidization gas in the distributor, [T.sub.D].
Option 3 is recommended to avoid fluidization. By extending the overall length for the melting step, and by using kneading-block configurations that can be operated partially filled, the trapped air is conveyed forward into the barrel and removed through a vent barrel.
Fluidization in tapered vessels is a useful fluid-solid contacting technique with a variety of application in drying (Becker and Salans, 1960; Mathur and Epstein, 1974), combustion (Khoshnoodi and Weinberg, 1978), gasification (Salam and Bhattacharya, 2006), waste water cleaning (Scott and Hancher, 1976), bioreactors (Scott and Hancher, 1976), food processing (Depypere et al., 2005), plasma (Flamant, 1994) and microwave (Feng and Tang, 1998) assisted processing, etc.
Halow worked at NETL for more than 25 years where he conducted experimental and modeling studies of fluidization, fluid- solids flow systems and modeling of energy processes including gasification, combustion and power generation.
Based on an initial fluidization analysis in SCHWING's lab, bench scale experiments under reaction conditions can be performed, and can then be further optimized in the scaled up pilot plant.
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.
The literature [16] discussed in detail the applicability and accuracy of the CIP method in describing the large deformation and fluidization motion characteristics of the viscous material.
According to [1, 2], these modifications may be related to gravitational effects, fluid movement, density contrast, sediment instability, and overloading influence by mechanism of fluidization or liquefaction.