Multi-stage fluidized bed

Kwauk, M., Pneumatically Controlled Multi-Stage Fluidized Beds (in Chinese, unpublished), Inst. Chem. Metall., 1974-3-7 (1974b). 

The downcomer (or dipleg, or standpipe) through which solids move from bed to bed is a key component of a circulating or a multi-stage fluidized bed. It is often connected at the lower end to a mechanical or non-mechanical valve for controllable transport. The so-called V-valve is a conical (tapered) spout installed at the lower end of a fully fluidized dipleg for controlling... 

Fig. 12. The cross-flow multi-staged fluidized bed reactor concept used in the Shell Shale Retorting Process (Poll et al., 1987).

Fig. 5.6. Multi-stage fluidized bed reactor (Jonke, A. A., Levitz, N. M. and Petkus, E. J. Ref. 25).

Fixed-bed reactors (multi-tubular and staged adiabatic), fluidized-bed reactors (bubbling bed, turbulent bed, fast, and transport or pneumatic), radial flow reactor, gauz reactor... 

Fig. 30. Contacting patterns and contactor types for gas-liquid-solid reactors, (a) Co-current downflow trickle bed. (b) Countercurrent flow trickle bed. (c) Co-current downflow of gas, liquid, and catalyst, (d) Downflow of catalyst and co-current upflow of gas and liquid, (e) Multi-tubular trickle bed with co-current flow of gas and liquid down tubes with catalyst packed inside them coolant on shell side, (f) Multi-tubular trickle bed with downflow of gas and liquid coolant inside the tubes, (g) Three-phase fluidized bed of solids with solids-free freeboard, (h) Three-phase slurry reactor with no solids-free freeboard, (i) Three-phase fluidized beds with horizontally disposed internals to achieve staging, (j) Three-phase slurry reactor with horizontally disposed internals to achieve staging, (k) Three-phase fluidized bed in which cooling tubes have been inserted coolant inside the tubes. (1) Three-phase slurry... 

More common, however, is the spraying of concentrate onto particles in a fluidized bed of a down stream dryer. Of course, this is only possible if two or multi-stage dryers are used [6.4.1.1, B.97]. Growth agglomeration (Chapter 5) occurs after re-wetting the surfaces of the partially dried particles. 

Klaren, D. G. and Holberg, N., "Development of a Multi-Stage Flash/Fluidized Bed... 

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.

Schoenfelder H, Werther J, Hinderer J, Keil F. A multi-stage model for the circulating fluidized bed reactor. AIChE Symp Ser 90(301) 92-104, 1994. 

Veenman AW. Heat transfer in a multi-stage flash/fluidized bed evaporator (MSF/FBE). Desalination 22 55-76, 1977. 

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