Baffle design

Lemieux, E. J., Data for Tower Baffle Design, Hydro. Processing Sept. (1983) p. 106. 

Fixing as constants those variables that are not open to change (for example, selecting a particular type of coating pan, spray gun, mixing baffle design, pan loading, etc.). 

Baffles designed to prevent drift loss by providing tortuous air passage prior to elimination of exhaust air stream. 

Fig. 1. Baffle designs, (a) Normal design (b) design for glass and coated vessels (baffle basket with pressure-fitted ring). (Reprinted with permission from the publisher, VCH Publishers, Inc., after Zlokarnik and Judat, 1988.)...

The type of exchanger influences cleaning frequency. For example, spiral-plate units are often used in fermentation plants, owing to the ease of solid resuspension and the devices nonplugging characteristics. A rod-baffle design provides more-effective shellside turbulence at a lower pressure drop than a segmented-baffle unit, so the former is likely to have less fouling. 

In the baffled design, the shell-side fluid is fed through a central perforated distributor. It flows radially through the fiber bundle, around a baffle located in the middle of the module, and leaves the module through the central distributor. As in conventional extraction, the mass transfer of solute occurs across a liquid-liquid interface. However, unlike in conventional extraction, the interface is maintained at micrometer-size pores, and three mass-transfer resistances are present tube-side (k,), shell-side (k,), and pore or membrane-side (k ). The overall mass-transfer coefficient based on the tube-side liquid k is given by... 

In steel or alloy vessels, the recommended baffle design for suspension of settling solids is four, flat-blade baffles, each baffle with a width, B, equal to r/12, and a wall clearance of at least 7/72. The baffles should extend to the lower end of the straight section of the cylindrical vessel, at the intersection of the cylindrical section with the bottom dish head. In glass-lined equipment, the recommended baffles are either fln or beaver tail types.A minimum of two baffles is recommended. These baffles are generally less effective than the standard four flat-blade baffle design. 

Impeller power consumption, P, is primarily a function of system characteristics like impeller speed, N, impeller diameter, P, impeller design, physical properties of fluid, vessel size and geometry, impeller location and baffle design. Through extensive experimental work, correlations determining the... 

Most conditions and features of the conceptual process are chosen to assure high throughputs (small equipment) and hence relatively low capital and fixed costs. These include the choice of flow regimes, heat carriers (density and heat capacity) and the solids-to-gas weight ratios. Attendant features of the process, such as baffle design and gas routing, are chosen to achieve operability and optimum operation. 

Stirred-tank reactors equipped with high-speed impellers are normally equipped with two or four baffles designed to prevent the formation of a vortex and rotation of the reaction mixture with the stirrer, as illustrated in Figure 4. Each baffle has a width of between 0.08 and 0,12 times the tank diameter. In normal practice, there is a space between the tank wall and the baffle equal to about one-third the baffle width. It is also desirable to keep the baffles off the bottom of the tank to keep solids from depositing. 

The objective of this scale model study was to develop a set of windbox baffles designed to provide an even combustion air mass flow distribution between the two burners, uniform peripheral flow entering each burner. 

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