Cylindrical flat bottom stirred vessel

Joosten et al. (1977) and Kolar (1967) also studied suspension of solids in stirred vessels. The correlations of Baldi et al. (1978) and Zwietering (1958) are based on data over a wide range of conditions and are also in good agreement with each other. Baldi et al. (1978) also proposed a new model to explain the mechanism of complete suspension of solid particles in cylindrical flat-bottomed stirred vessels. According to this model the suspension of particles at rest on certain zones of the tank bottom is mainly due to turbulent eddies of a scale of the order of the particle size. The model leads to an expression... 

Stirred vessel Figure 2.5(a) (Cylindrical flat bottom vessel, four baffles). Impeller six-flat blade turbine type. 

Stirred vessel Figure 4.4 (Cylindrical flat bottom, DT = 6, 18, 54 cm). Impeller FBDT impeller. 

STR, stirred tank reactor consisting of a cylindrical vessel (diameter 30 cm, volume 21.2 1) with a flat bottom and four symmetrical baffles and a six-blade disc impeller with a diameter of 10 cm. Screw loop reactor, with the volume of the dispersing zone about 64 ml and a reactor volume of 1.67 1. 

Geometry For a stirred tank, the geometry is cylindrical, with a small aspect ratio (the height of fluid in the tank [H], is one to three times the tank diameter [T]). Although many industrial vessels have a dished bottom (especially if solids suspension is involved), simulations to date have used the simpler flat bottom geometry. The impeller, of diameter D = T/4 to T/2, is placed at the desired off-bottom clearance (C). Around the tank walls, two to four rectangular baffles are evenly... 

A typical stirred-tank reactor is shown in Fig. 5.4-3. It is a cylindrical vessel with elliptical or torospherical bottom and cover. It is equipped with an axially mounted stirrer rotating with a speed from 25 rpm (large scale) to 2000 rpm (laboratory). Fig. 5.4-4 shows the stirrers that are mostly used in fine chemicals manufacture, viz. the marine propeller, turbine, flat- or pitched-blade agitator, and anchor. Agitators move the fluid into axial and radial direction. Marine propellers and pitched-blade stirrers predominantly impose axial motion. 

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