Fluidized-bed granulation

Despite the importance of fluidized bed granulafion wifhin the food indusfry, fhere is relafively little published literature on the operation of fluidized beds used for agglomeration, instantising, coating or encapsulation of food materials and consequently very little 

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The effect of fluid penetration rate and the extent of penetration on granule size distribution from drum granulation experiments is illustrated in Fig. 20 (since no example for fluidized bed granulation is available). From Fig. 20, it is clear that for fluids with a similar extent of penetration, increasing the penetration rate increases the average granule size for various levels of liquid loading. 

Figure 25. Experimental data from fluidized bed granulation. (From Ennis, et al., Powder Technol., 65 257-272, 1991, with kind permission from Elsevier Science S.A., P.O. Box 564, 1001 Lausanne, Switzerland.)...

Nienow, A. W., Fluidized Bed Granulation, Enlargement and Composition of Particulate Solids, (N. G. Stanley-Wood, ed.), Butterworth and Co., London (1983)... 

Nienow, A. W., Fluidized Bed Granulation and Coating Application to Materials, Agriculture and Biotechnology, Proceedings of the First International Particle Technology, Forum, Denver, CO., USA (1994). 

Waldie, B., Growth Mechanism and the Dependence of Granule Size on Drop Size in Fluidized-Bed Granulation, Chem. Eng. Sci., 46 2781-2785 (1991)... 

The heat input into the fluidized bed granulation process is controlled with a steam control valve. The settings for the sensors and controls used in the Glatt unit are listed (Table V). 

Full Scale Giatt Mixing. The fluidized bed granulator is one of the most important granulation methods available today, because it combines the unit operations of mixing, granulating, and drying into... 

Fluidized bed granulators, or dryers, often require high temperature sensors which are available from many different OEMs and suppliers standard sensors operate only in the 0-70 °C interval. All accelerometers and AE sensors have small dimensions, which makes mounting easy. Figure 9.3 shows how to fix the sensor and cable properly in order to avoid nomelevant vibrations from occurring and interfering with the measurements. 

Fluidized bed granulation monitoring of a fertilizer product (urea) in a semi-industrial pilot plant (SIPP), illustrating the main features and benefits. 

Monitoring of a start-up sequence of a continuous fluidized bed granulator... 

Figure 13.3 A schematic diagram of agitation fluidized bed granulator (NQ-i60, Fuji Paudal). i Agitation fluidized bed. 2 Bag filter. 3 Spray nozzle. 4 Blower. 5 Heater. 6 Motor. 7 Agitator blade. 8 Slit plate. 9 Image probe. 10 Image processing system. II Host computer. 12 Controller. 13 Pump. 14 Binder. Reprinted from Watano et al. (2001) with permission from Elsevier Science.

X. Hu, J.C. Cunningham and D. Winstead, Study growth kinetics in fluidized bed granulation with at-line FBRM, Int. J. Pharm., 347, 54-61 (2008). 

However, for Re < 10 the experimental values of Nu fall sharply with decreasing Reynolds number, well below the theoretical minimum of Nu = 2. This is attributable in part to experimental difficulties, for example fhe problem of measuring particle temperature, and in part to the theoretical interpretation of the data. Botterill (1975) posed the question of what exactly is measured by a bare wire thermocouple inserted in a fluidized bed. Despite the uncertainties in the experimental evidence, Botterill concluded that it probably does indeed measure the particle temperature. This was the assumption of Smith and Nienow (1982) who used bare wire thermocouples to measure bed particle temperatures during fluidized bed granulation. In the region Re < 10, as Kunii and Levenspiel (1991) indicate, the data can be represented by an expression due to Kothari... 

Figure 5.6 Temperature gradients in fluidized bed granulation (Smith, 1980).

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