Material handling drying equipment

Proper equipment selection/design Adequate instmmentation/control Proper material handling (drying/feeding)... 

Drying equipment also can be made available with means to accelerate the drying process if these means are acceptable to product quality. Far example, agitation, stirring, and otherwise keeping the material to be dried in constant motion naturally assists the amount of exposure of surfaces to the drying medium. Numbers of materials, however, cannot be handled in this fashion and require relatively conservative, still conditions. 

Drying equipment may be classified in several ways. The two most useful classifications are based on (1) the method of transferring heat to the wet solids or (2) the handling characteristics and physical properties of the wet material. The first method of classification reveals differences in dryer design and operation, while the second method is... 

These tests should establish the optimum operating conditions, the ability of the dryer to handle the material physically, product quality and characteristics, and dryer size. The principal manufacturers of drying equipment are usually prepared to perform the required tests on dryers simulating their equipment. Occasionally, simple laboratory experiments can serve to reduce further the number of dryers under consideration. 

Elaborate classification of dryers has been presented by Kroll (1978) and Keey (1972) but less comprehensive (but perhaps more practical) classifications are shown in Table 9.1. In this table, the method of operation, physical form of the stock, scale of production, special features, and drying time are presented. Two other classifications of dryers may be found in Perry (1999). One classifies the equipment on the basis of heat transfer (Figure 12-45) and the other on the basis of the material handled (Table 12-9) in Perry. 

CLASSIFICATION OF DRYERS. There is no simple way of classifying drying equipment. Some dryers are continuous, and some operate batchwise some agitate the solids, and some are essentially unagitated. Operation under vacuum may be used to reduce the drying temperature. Some dryers can handle almost any kind of material, while others are severely limited in the type of feed they can accept. 

Besides the gas handling, heating, and cleaning facilities, the two most important system components are the equipment for dispersion of the wet feed and the containment in which hot gas contacts the dispersed wet material and drying takes place. 

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