Process operations agglomeration

The process can agglomerate and remove particnlates smaller than 1, im only if a snfficient number of particulates are present to allow collisions between particulates in the aconstic field. Other potential disadvantages include the requirements for sound containment and the power requirement for operating the acoustic source. 

Granulation is a process of agglomeration where signiLcant particle growth is accomplished in a powder blend by the addition of binder solution. The unit operation is intended to ensure content uniformity, improve blend Low, provide narrow particle size distribution, and density the material. 

The sequence of process operations for coal agglomeration is depicted in the generalized flow diagram of Fig. 8.2. Possible equipment for each step is also indicated. In general, equipment well-known in the chemical and mineral industries can be applied in the process. The operations consist of selective flocculation or microagglomeration, agglomerate recovery with simultaneous impurity rejection, further size enlargement of the recovered and... 

The last three process operations size reduction, agglomeration, and size separation pertain to solids. Examples of size reduction are grinding and shredding. An example of agglomeration is compression of powders to form tablets. Screening to sort out oversized particles is an exaii5)le of size separation. 

So far, in all examples the method for agglomeration was based on the use of low-density gas fluidized beds. As discussed in Chapter 5 and in much more detail in earlier publications [B.48, B.93, B.97], adhesion by coalescence of irregularly moving particles in low-density fluidized beds yields relatively small, structurally loose, and low-strength agglomerates, which (if reconstitution in liquids is desired) exhibit instant characteristics. In most cases these processes operate continuously, but batch operations for very sensitive materials (vitamins) are also possible. Fig. 6.4.1-16 shows as examples the photomicrographs of two typical products (dry milk and coffee extract). 

Spray drying is a one-step continuous processing operation that can transform feed from a fluid state into a dried form by spraying the feed into a hot drying medium. The product can be a single particle or agglomerates. The feed can be a solution, a paste, or a suspension. This process has become one of the most important methods for drying liquid foods to powder form. 

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