Fluidized bed of inert particles

Copeland A process for oxidizing organic wastes in a fluidized bed of inert particles. The wastes may be solid, liquid, or gaseous, and the oxidant is air. Inorganic residues are collected as granular solids and the heat generated is normally utilized. Developed and marketed by Copeland Systems, Oak Brook, IL, United States, and used in a wide variety of industries. 

The direct sterilisation of particulafe solid foods in a gas-solid fluidized bed was proposed as long ago as 1968 by Lawrence et al. (1968) who sterilised wheat flour in steam-air mixtures at the pilot scale. However, Jowitt (1977) described an atmospheric pressure process for fhe sferilisation of canned foods in which the cans are immersed in a fluidized bed of inert particles. This has a number of advantages compared to the conventional retorting process using pressurised steam or hot water ... 

An increase of the limiting current density can be achieved by using a fluidized bed of inert particles (e.g. glass beads) with diameters of several tenths of a millimeter up to about... 

The advantages of a fluidized bed of inert particles can best be judged from the dependence of the limiting current, j, on... 

Figure 9. Scheme of an electrolyser with a fluidized bed of inert particles. 1 Electrolyte, 2 inlet grid, 3 outlet grid, 4 flow meter, 5 valve, 6 pump, 7 reservoir. 

Tatemoto, Y. and Miyazawa, K., Drying of suspensions in a fluidized bed of inert particles under reduced pressure. Drying Technol, 29,1204-1209, 2011. 

Enzyme spraying onto a heated fluidized bed of inert particles US 4,617,272 Disaccharide-stabilized enzyme preparation EP 0,501,375 A1... 

Kutsakova VE, Utkin YV. Dr3dng kinetics of proteineous pastes, emulsions and solutions on fluidized bed of inert particles. Zhumal Prikladno Khimii 60(5) 1143-... 

Pan YK, Li JG, Zhao LJ, Ye WH, Mujumdar AS, Kudra T. Drying of a dilute suspension in a vibrated fluidized bed of inert particles. Proc. 12 Inti. Drying Symposium (IDS 2000), Coumans WJ, Kerkhof PJAM, eds. Noordwijkerhout, The Netherlands, Paper 266, 2000. 

Figure 4 Mass transfer coefficients between immersed isolated active particles and a fluidized bed of inert particles. (Shaded area range of particle-gas mass transfer coefficient measured in a fluidized bed of only active particles).

Fluidized bed dryers (FBDs) have found widespread applications for the drying of particulate or granular solids in the chemical, food, ceramic, pharmaceutical, agriculture, polymer, and waste management industries. More recently, they have also found special applications in the drying of slurries. Suspensions, solutions, dilute pastes, or sludges are atomized into a fluidized bed of inert particles and the dry powder is separated from the exhaust gases. 

Tatemoto Y, Sawada T Numerical analysis of drying characteristics of wet material immersed in fluidized bed of inert particles. Drying Technol 30 979—988, 2012. 

The pressure losses in a fluidized bed of inert conducting particles can well be estimated from the approximate equation... 

Hatamipour, M.S. and Mowla, D., Drying behaviour of maize and green peas immersed in fluidized bed of inert energy carrier particles, Food Bioproducts Process. J., 84, 1-7, 2006. 

Despite extensive studies on drying on inert particles, there is practically no data on the material residence time except those cited here for a swirling bed of inert particles. Also, the material residence time from 30 to 85 seconds has been specified for drying of animal blood and egg products dried as a film of 60 to 200 pm on a fluidized bed of 3- to 5-mm Teflon cubes (Table 4.2). Such a substantial residence time as compared to the residence time of a drying air was claimed to be sufficient to suppress undesirable microorganisms when combined with the material temperature in the range from 70° to 90°C (Rysin et al., 1981). 

In a continuous system, the band of drying material is transported in a serpentine fashion through the fluidized bed of sorbent particles. Heat required for moisture release from the sorbent to fluidizing air is supplied by immersed heaters. The use of fluidized beds of active particles enhances not only the convective but also material-sorbent, sorbent-sorbent, and sorbent-heater contact heat/mass transfer rates. Comparison of the fluid bed dryer with inert sorbent with the cylinder dryer is given in Table 12.1. 

Another method developed by Hercules Inc. (9) consisted of reacting crystalline polypropylene with maleic anhydride in the presence of organic peroxide in an inert liquid organic solvent. This process is expensive because it requires the separation of solvent and excess maleic anhydride from the modified polypropylene. A similar process, detailed in patent 3,414,551, uses a fluidized bed of polymer particles instead of a solvent. 

The third scheme, Fig. 2C, is low-pressure (near atmospheric pressure) circulating bed air blown partial oxidation of biomass fuel. Here low-pressure biomass fuel is fed as a dry solid into a circulating bed of inert particles fluidized by low-pressure air and steam. The... 

Fluidized material Particulate solid Paste/slurry sprayed onto a bed of inert particles Slurry sprayed onto absorbent particles (e.g., silica gel, biomass, etc.)... 

Yang J, Renken A. Intensification of mass transfer in liquid fluidized beds with inert particles. Chemical Engineering and Processing 37 537 544, 1998. 

If the titanate cannot be diluted with a matrix-compatible Hquid, the filler can be pretreated by atomizing imdiluted titanate into a fluidized bed of filler particles. The neoalkoxy titanates are available in dry powder form as >65% concentrates on an inert carrier. These can be used to pretreat filler by intimate dry blending, although substrate coupling actually occru s in situ dmnng compoimding. 

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