Stirred tank design draft tubes

A basic stirred tank design is shown in Fig. 23-30. Height to diameter ratio is H/D = 2 to 3. Heat transfer may be provided through a jacket or internal coils. Baffles prevent movement of the mass as a whole. A draft tube enhances vertical circulation. The vapor space is about 20 percent of the total volume. A hollow shaft and impeller increase gas circulation (as in Fig. 23-31). A splasher can be attached to the shaft at the hquid surface to improve entrainment of gas. A variety of impellers is in use. The pitched propeller moves the liquid axially, the flat blade moves it radially, and inclined blades move it both axially and radially. The anchor and some other designs are suited to viscous hquids. 

FIG. 23-30a A basic stirred tank design, not to scale, showing a lower radial impeller and an upper axial impeller boused in a draft tube. Four equally spaced baffles are standard. H = beigbt of liquid level, Dj = tank diameter, d = impeller diameter. For radial impellers, 0.3 < d/Dt < 0.6. 

Stirred tank design, 287,288 baffles, 287 draft tubes, 287... 

Figure 5-12. Typical proportion of stirred tank design with radial and axial impellers and baffles. The upper axial impeller is housed in a draft tube. For radial impellers,. 3 < d/Dt <. 6...

Figure 11.12 shows the different designs of the simple FC group depending on the crystallization process such FC crystallizers can be used for (vacuum cooling crystallization or vacuum evaporative crystallization), one can find the typical FC , and with and without a tube and shell heat exchanger. These are the simple stirred tank 0, the draft tube (DT) crystallizer (2), and the FC crystallizer ((J), ). 

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