Centrifugal fluidized beds

Figure 1.20 Centrifugal fluidized bed. From Hanni et al. (1976), by permission of the Institute of Food Technologists, USA.

Carlson, R.A., Roberts, R.L. and Parkas, D.F., Preparation of quick-cooking rice products using a centrifugal fluidized bed, /. Food Sci., 41 (1976) 1177-1179. 

Chen, G.F., Wang, W., Yan, H. and Wang, X.Z., Experimental research on mass transfer in a centrifugal fluidized bed dryer. Drying Tech., 17 (1999) 1845-1857. 

For fine grinding of limestone for paper and pottery manufaeturing, respectively, bead mills are widely used. The beads of steel, glass, or eeramic have a diameter of 0.2. 3mm and occupy up to 90% of the total mill volume (cp < 0.9). They are kept in motion by perforated stirrer dises while the liquid/solid suspension is pumped through the mill chamber. Mill types frequently used are the stirred disc mill, centrifugal fluidized bed mill, and ring gap mill. 

Karbstein H, Muller F, Polke R. Scale-up of centrifugal fluidized bed mills (in German). Aufarbeitungstechnik 1996 37 469-479. 

Figure P9.1. Cross-sectional view of the centrifugal fluidized bed.

The same result is also found in centrifugal fluidized bed mills, Fig. 53. Finer particles than 1 pm are not produced. 

FIGURE 29.3 Modified design of centrifugal fluidized bed dryer allows for lower pressure drops and better heat economy. As the air velocity is increased, the degree of fluidization changes from packed to spouted. (From Brown, G.E. et ah. Food TechnoL, 26(12), 23, 1972. With permission.)... 

FIGURE 29.4 Isometric view of centrifugal fluidized bed drying system. (1, dryer cylinder 2, drive pulley 3, aspiration feeder 4, feeder blower 5, discharge chute 6, air blower 7, air discharge damper 8, steam coil heater 9, plenum 10, air vent 11, vent port 12, recirculating duct 13, make-up air 14, blower intake). (From Hanni, P.F. et al., J. Food ScL, 41(5), 1172, 1976. With permission.)... 

Operating Conditions for Drying Some Vegetables in Continuous Centrifugal Fluidized Bed Dryer... 

Feed Rates and Evaporation (kg/h) for a Range of Continuous Centrifugal Fluidized Bed Dryer Sizes... 

G.E. Brown, D.F. Farkas, and E.S. De Marchena, Centrifugal fluidized bed blanches, dries and puffs piece-form foods. Food TechnoL, 26(12) 23 (1972). 

Hanni PF, Farkas DF, Brown GE. Design and operating parameters for a continuous centrifugal fluidized bed dryer (CFB). J Food Science 41 1172-1176, 1976. 

Lazar ME, Parkas DF. The centrifugal fluidized bed (CFB) 2. Drying studies on piece-form foods. J. Food Science 36 315-319, 1971. 

Roberts RL, Carlson RA, Parkas DF. Preparation of a quick-cooking brown rice product using a centrifugal fluidized bed dryer. J Food Sci 45 1080-1081, 1980. 

Figure 2 Variations of fluidized bed reactor configurations, (a) Baffled bed, (b) multi-stage bed, (c) multi-stage with counter-current solid flow, (d) multi-stage with external solid circulation, (e) fluidized bed with online solid exchange, (f) multi-cell bubbling bed, (g) CFB, (h) centrifugal fluidized bed, (i) downer, (j) spouted bed.

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