Laboratory drying

In most laboratories, drying ovens maintained at about 50° are available for the final drying of glass apparatus of all kinds. 

Harjum Oxide. This compound [1304-28-5] (Class 1, nonregenerative) is used primarily as a laboratory drying agent (4). It is the only drying agent that continues to dry even at red heat. Barium oxide is relatively expensive and cannot be regenerated by conventional methods. Therefore, it is not used extensively in commercial appHcations (see Barium COMPOUNDS). 

Direct type, hatch operation Laboratory drying capacities, investment and operating costs are high. Long drying times ments under Pastes and Sludges... 

The operator of an analytical balance should keep in mind that this instrument is extremely sensitive and, therefore, must be handled carefully and correctly. Also, this discussion presumes that, if necessary, the sample has been dried (such as in a laboratory drying oven) and has been kept dry (such as by storing in a desiccator) prior to weighing. 

For laboratory drying a crystalline or powdered sample of expl is spread in a thin layer on a sheet of filter paper and left overnight in a warm room. The next day, the sample is placed in a vacuum oven at ca 55°C with 18—25 inches of vacuum and kept there until constant wt (2 or more hrs). Expls can also be dried by the methods for drying NC described in detail in Vol 3 of Encycl, p D45-L... 

Performances of dryers with simple flow patterns can be described with the aid of laboratory drying rate data. In other cases, theoretical principles and correlations of rate data are of value largely for appraisal of the effects of changes in some operating conditions when a basic operation is known. The essential required information is the residence time in the particular kind of dryer under consideration. Along with application of possible available rules for vessel proportions and internals to assure adequate contacting of solids and air, heat and material balances then complete a process design of a dryer. 

A detailed example of capital and operating costs of a jacketed vacuum dryer for a paste on which they have laboratory drying data is worked out by Nonhebcl and Moss (1971, p. 110). 

In practice, and in most soil laboratories, drying the soil is, in general, the only option. Where drying the soil would entail a loss of essential information it may be preferable to make use of the soil solution itself obtained, for example, by centrifugation or displacement (Sanders, 1983 Linehan et al., 1985) rather than trying to use field-moist soils. 

Compound Retention index calculated Rl literature Fresh seed oil Laboratory-dried seed oil... 

Proximate analyses of the fuel and char were run using a standard laboratory drying oven, muffle furnace, and analytical balance according to ASTM Standard Methods. Ultimate Analysis for percent C, H, N, S, and O in the fuel char, and condensate was conducted by the Chemistry Department, University of California, Berkeley. The energy content of the fuel and char was determined with a Parr Oxygen Bomb Calorimeter. 

A further caution to be exercised when selecting dryers is not to be biased by the way the product is made in the laboratory. Drying as well as filtration, at extremely small scales, are very different from that at a scale that is several orders-of-magnitnde larger. Some materials may start to form hard lumps under their own weight—this may not show in pilot tests if the prodnct depth is under the critical depth needed to prodnce lumps. A double-cone vacuum dryer, for example, has a tendency to form snowballs on fnll-scale but not necessarily on pilot-scale equipment (Kemp 1998). 

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