Drying in fluidized beds

In Equations 7.26 and 7.26b w is the moisture content of the material at time t, Wg is the surface moisture content of the material, rvi is the initial moisture content of the material, Sp is the surface area of particles, Vp is the particle volume, and D is the diffusion coefficient. 

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Giner, S.A. and Calvelo, A., Modelling of wheat drying in fluidized beds,... 

Law, C.L., Tasirin, S.M., Daud, W.R.W., and Geldart, D., Effect of vertical baffles on particle mixing and drying in fluidized beds of group D particles. China Particuol. Sci. TechnoL Particles, 1(3), 115-118, 2003. 

P.G. Romankov and N.B. Rashkovskaya, Sushka v vzvesh-ennom sloye (Drying in fluidized bed), Chimiya, Leningrad, Russia, 1979. 

Jacob, M. (2013) Vacuum Drying in Fluidized Beds, Vortrag, GVT-University Course Fluidization Technology, Hamburg, November 4-7, 2013. 

Groenewold, H., Tsotsas, E., 2007. Drying in fluidized beds with immersed heating elements. Chem. Eng. Sci. 62 481-502. 

Romankow, P. G., Raschkovskaja, N. B., 1968. Drying in fluidized beds (in Russian), Chimia, Leningrad, UDSSR, p. 357. 

The chlorination is mostly carried out in fluidized-bed reactors. Whereas the reaction is slightly exothermic, the heat generated during the reaction is not sufficient to maintain it. Thus, a small amount of oxygen is added to the mixture to react with the coke and to create the necessary amount of heat. To prevent any formation of HCl, all reactants entering the reactor must be completely dry. At the bottom of the chlorination furnace, chlorides of metal impurities present in the titanium source, such as magnesium, calcium, and zircon, accumulate. 

Similar to processing mined rock salt, solar salt may be cmshed, screened, and kiln dried or fluidized-bed dried. Coarse solar salt is a premium product because of high purity and relatively large crystal size. It is in particular demand for use to regenerate the resin in cation-exchange water softeners... 

Particle Structure. First of all, the particle structure has a fundamental influence on the degradation propensity. The extent of degradation as well as its mode will strongly depend on whether the particle is a single crystal, has an amorphous structure or is an agglomerate. For example, spray-dried catalysts, which are often used in fluidized bed reactors, are... 

Agarwal, P. K. and la Nauze, R. D. Chem. Eng. Res. Des. 67 (1989) 457. Transfer processes local to the coal particle. A review of drying, devolatilization and mass transfer in fluidized bed combustion. 

In addition to the vertical mixing of solids, a degree of horizontal mixing occurs and this is especially important in long, shallow plug flow beds of the type used in fluidized bed drying or freezing (see Chapter 3). 

Reay and Baker (1985) suggest that there are two types of particle which are encountered in fluidized bed drying fype A parficles which dry easily and where the water vapour in the gas leaving the bed is in equilibrium with the moisture in the particle and type B particles which have a high internal resistance to the mass transfer of water and therefore dry very slowly. Wheaf is an example of fhe latter (Giner and Galvelo, 1987). 

Markvart, M., Vanecek, V. and Drbohlav, R., The drying of low melting point substances and evaporation of solutions in fluidized beds, Br. Ghent. Eng., 7 (1962) 503-507. 

These mechanisms or rate processes can occur simultaneously in all processes, ranging from spray drying to fluidized beds to high-shear mixers. 

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