Tower dryers/furnaces

The tower dryer is basically a chimneylike structure made up of bricks, insulated steel, or concrete. Hot gases from a furnace are led through the bottom whereas the wet solids flow downward countercur-rently to the drying medium. The flow of the solid... 

Fig. 6-11. Schematic diagram of the kraft pulping process (6). 1, digester 2, blow tank 3, blow heat recovery 4, washers 5, screens 6, dryers 7, oxidation tower 8, foam tank 9, multiple effect evaporator 10, direct evaporator 11, recovery furnace 12, electrostatic precipitator 13, dissolver, 14, causticizer 15, mud filter 16, lime khn 17, slaker 18, sewer.

Figure 2 is a photograph of a large, complex plant. Plants such as this contain reactor furnaces, distillation towers, heat exchangers, separators, dryers, compressors, and various other units as required by the specific feedstock and product distribution achieved. Figure 3 shows a simplified diagram of a plant. 

Continuous dryers, ovens, incinerators, and furnaces take any of a variety of forms such as rotary drum, tower, shaft, tunnel oven, multihearth (Herreshoff) kiln, and fluidized bed. As with all continuous furnaces, their design is very dependent on how the load(s) can be moved through the furnace (or occasionally, how the furnace can be moved over the loads). 

Vatical strip heating furnaces are sometimes called tower furnaces, but should not be confused with towa- dryers (sec. 4.2.4)... 

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