Dryers performance, comparative

Performance and Cost Data for Turbo-Tray Dryers Performance data for three apphcations of closed-circuit diying are included in Table 12-29. Operating, labor, and maintenance costs compare favorably with those of direct-heat rotating eqmpment. 

Another important class of dryer is the fluidized-bed dryers. Some designs combine spray and fluidized-bed dryers. Choice between dryers is usually based on practicalities such as the materials handling characteristics, product decomposition, product physical form (e.g., if a porous granular material is required), etc. Also, dryer efficiency can be used to compare the performance of different dryer designs. This is usually defined as follows -. 

TABLE 9.3. Comparative Performances of Basic Dryer Types... 

In a later section, the characteristics and performances of the most widely used equipment will be described in some detail. Many types are shown in Figure 9.4. Here some comparisons are made. Evaporation rates and thermal efficiencies are compared in Table 9.2, while similar and other data appear in Table 9.3. The wide spreads of these numbers reflect the diversity of individual designs of the same general kind of equipment, differences in moisture contents, and differences in drying properties of various materials. Fluidized bed dryers, for example, are operated as batch or... 

After washing their hands, consumers usually dry them with a towel, paper towel, or air-dryer. The HCPHWT does not incorporate a hand-drying step in the protocol. This allows for consistency within the method however, omitting this from the protocol ignores a commonly performed step as part of the handwashing process. This parameter needs to be accounted for when evaluating efficacy of antibacterial products because towel drying will physically remove bacteria from the hands [21,22]. Ansari et al. compared the removal of rotavirus and... 

The thermal efficiency of steam-tube dryers is in the range of 70%-90%, if well insnlated. This number does not allow for boiler efficiency, so it cannot be directly compared with that of direct-heat nnits, however. Heat transfer coefficients in steam-tube dryers may range from 30 to 85 W/(m K) and these values increase with increasing steam temperatnre dne to an increased effect of radiation. The heat flnx of these dryers, carrying satnrated steam at 140°C-170°C, may range from 6300 W/m for difficnlt-to-dry and organic prodncts to between 1900 and 3800 W/m for line inorganic materials. Typical performance data of steam-tube dryers on some selected applications are shown in Table 6.4 (Moyers and Baldwin, 1997). 

Comparative Performance of IR, Convective, and IR-MW-Vacuum Freeze Dryer for Black Currant... 

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