Granulating drum

Tumbling granulators Drums Discs 0.5 to 20 Moderate 0.5-800 ton/hr Very spherical granules Fertilizers, iron ore, non-ferrous ore, agricultural chemicals... 

A granulation drum consists of an inclined cylinder which may be either open-ended or fitted with annular retaining rings. Feeds may... 

TABLE 20-43 Characteristics of Large-Scale Granulation Drums ... 

Fig. 2. Schematic diagram of the equipment for granulation tests (1) granulator drum, (2) pneumatic nozzles, (3) engine, (4) inverter, (5) tripod, (6) rotameters, (7) water tank, (8) compressor, (9) tachometer, (10) torque meter, (11) reader, and (12) computer.

Characteristics of some fertilizer granulation drums. (Courtesy The A.J. Sackett and Sons Co.)... 

Some typical iron ore balling drums are described in Table 3.6. The L/D ratio of these drums is generally in the range 2.5 to 3.5, somewhat higher than that for fertilizer granulation drums. 

Space and energy requirements as well as investment costs are frequently factors that render an otherwise perfectly feasible and desirable process uneconomical and kill a project. Sometimes they also incorrectly direct the interest toward methods which, after superficial investigation, seem to offer cheaper alternatives. In this context it should be stressed that the entire process must always be considered. For example, for the granulation of fertilizers a granulation drum may seem to be the cheaper solution in comparison with a roller compactor if only investment costs are considered this may even be true if the entire system is investigated. However, if space requirements and energy (operating) costs are compared, a different conclusion may be obtained (see Section 5.4.4). 

The lifting coefficient d can be estimated from results obtained for ball charges in tube mills (Figure 104 ). For the typical granulation drum loadings of ( = 0.1 to 0.3, 6 is approximately constant. 

Fig. 10.22 Sketch describing the principle of the fluid granulation drum (FCD) for coating particles (courtesy Kaltenbach-Thuring, Beauvais, France).

The entire process must be considered. For example, in the granulation of fertilizers a granulation drum may seem cheaper than a roller compactor. If only investment costs are considered, this may still be true. However, if space requirements of the complete system, which includes dryer(s) and cooler(s), as well as the energy and operating costs for entire processes are compared, in many cases a different conclusion maybe drawn. 

Fig. 6.6-2 The d ischarge end of the granulation drum and the feed end of the rotary dryer of a wet fertilizer granulation plant (courtesy Krupp Polysius, Beckum, Germany)...

Fig. 6.6-35 Sketch ofa modified fluid granulation drum (FCD) forthe...

Industriemfi (Residence time distribution in granulation drums for industrial carbon black). Chemie Ingenieur Technik 75 (2003) 4, 354-358. 

Other flaky chemicals obtained from drum coolers or dryers that have similar properties as those of the fresh DMT can be similarly converted into dense free flowing intermediate products by pelleting, briquetting, or compaction/granulation. Drum dryers feature heated drums that either dip into a bath of suspended particles or are coated by means of axial dispensers with the suspension. As in the case of drum coolers, dry solids are removed from the drum with scrapers and are typically bulky and dusty before suitable agglomeration has taken place. 

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