Dry efficiency

Desiccants can lose water capacity and drying efficiency by taking up moisture during storage. They should therefore be analy2ed before use. If necessary, the materials should be reactivated (regenerated) before putting them in service. 

The data show a midrange dry efficiency of 0.7 (70 percent). They indicate a flood F-factor value of about 3.0. Thus, the approach to flood is 2.6/3.0 = 0.87 (87 percent). The data were taken at total reflux, and thus F c = (0.481/841)0.5 = 0.024 (densities taken from Example 9). From Fig. 14-26, = 0.19, and from... 

In the second development, the emphasis is on taking advantage of the increa.sed specific work associated with evaporative intercooling and of the increased mass flow and work output of the turbine. Any gain on the dry efficiency is likely to be marginal, depending on the split in pressure ratio. 

If the dry efficiency at this point in the column is 90%, the wet efficiency is calculated by means of Equation 291 ... 

The cylindrical space above the product container acts as a decelleration zone or expansion chamber. In the space above this chamber, a filter is used to separate the product from the air stream. During fluidization and drying, fines collect in the filter reducing aii volume and possibly drying efficiency (decreasing water removal rate). Periodically, fluidization must be interrupted by stopping air flow to shake fines out of the filter and back into the batch. 

The dry Murphree efficiency calculated thus far takes into account the vapor and liquid resistances and the vapor-liquid contact patterns, but is uncorrected for the effects of entrainment and weeping. This correction converts the dry efficiency to a "wet or actual Murphree tray efficiency. Colburn [Eq. (14-98), under "Entrainment ] incorporated the effect of entrainment on efficiency, assuming perfect mixing of liquid on the tray. 

At a 350°F burner temperature, the temperature drop from mlxpoint to tower outlet averaged 140°F for the insulated system and 159°F for the uninsulated system. These temperature drops were due not only to losses of heat from the drying systems, but also, in part, to heating the cotton. The Insulated system removed 120 grains of moisture per pound of cotton (gr/lb), whereas the uninsulated system removed only 92 gr/lb—Indicating an increase in drying efficiency due to insulation. 

Essentially odor-free carrier imparts no residual odor on the goods, even with low-temperature drying. Efficiently builds and levels disperse or cationic dyes on polyester, acts as a compatlbilizer for cationic and anionic dyes, and minimizes cross-stain in blend dyeing. 

The possible influence of residual moisture on the freeze-drying efficiency and on the stability of the freeze-dried vaccine during storage has been studied. Observations were made from three vaccines for animal use ... 

For the vaccine against brucellosis (Figure 2) [33], an optimal freeze-drying efficiency is observed for a residual moisture in the vicinity of 2.8% on the other hand, preservation during storage is best for the lower levels of residual moisture. The optimal result appears to be obtained for a residual moisture level in the vicinity of 2% (Figure 3). 

The vaccine against canine distemper also has an optimal residual moisture level at which an optimal freeze-drying efficiency can be obtained this optimum is located at approximately 2% (Figure 4). Stability during storage appears to be improved by a residual moisture of approximately the same order (1.8% Figure 5). 

On the other hand, in the conditions under consideration, the vaccine against poultry infectious bronchitis does not reveal an optimal residual moisture level for freeze-drying efficiency. However, stability during storage at 5°C appears to be best for lower residual moisture levels (Figure 6). 

Figure 3 Brucella. Viability in terms of the residual moisture (sum of freeze-drying efficiency and viability after a storage of 5 months at 6°C).

The Karl Fischer method may be used in many cases. An extremely sensitive method using tritiated water as tracer for the determination of solvent water content has been developed [268] in which drying efficiency is determined by the addition of a specified amount of tritium-labeled water to a rigorously dried solvent and subsequent determination of the decrease in activity of the solvent after treatment with the drying agent. 

As the products and their volumes may differ, each vessel can be removed from the manifold separately as its drying cycle is completed. Also, the close proximity to the collector creates an environment that maximizes the drying efficiency. 

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