Granulation drying

The main purpose of pesticide formulation is to manufacture a product that has optimum biological efficiency, is convenient to use, and minimizes environmental impacts. The active ingredients are mixed with solvents, adjuvants (boosters), and fillers as necessary to achieve the desired formulation. The types of formulations include wettable powders, soluble concentrates, emulsion concentrates, oil-in-water emulsions, suspension concentrates, suspoemulsions, water-dispersible granules, dry granules, and controlled release, in which the active ingredient is released into the environment from a polymeric carrier, binder, absorbent, or encapsulant at a slow and effective rate. The formulation steps may generate air emissions, liquid effluents, and solid wastes. 

Solid bed dehydration systems work on the principle of adsorption. Adsorption involves a form of adhesion between the surface of the solid desiccant and the water vapor in the gas. The water forms an extremely thin film that is held to the desiccant surface by forces of attraction, but there is no chemical reaction. The desiccant is a solid, granulated drying or dehydrating medium with an extremely large effective surface area per unit weight because of a multitude of microscopic pores and capillary... 

The production process consists of the stages of preparation of the monomer and additive solutions elimination of the dissolved oxygen from the solutions polymerization compounding (i.e., stabilization and granulation) drying, crushing, and packing of the finished product. 

Nevertheless, the acquisition of a sufficiently detailed body of physical information can allow a formulator to go far beyond the mere ability to cope with crises when they develop at unexpected times. For a well-understood system, it is theoretically possible to design an automated or semi-automated manufacturing scheme for which the processing variables would be appropriately controlled so as to minimize the possibility of batch failure. Materials passing the hurdles of physical test specifications would be totally predictable in their performance, and they could therefore be blended, granulated, dried, compressed, and delivered into containers without operator intervention. 

Fig. 6.12. Spectra from a granulation drying process. The bound and free water are seen at 1420 and 1440nm, respectively.

High-energy processes (milling, lyophilisation, granulating, drying) can introduce certain amounts of amorphicity into otherwise highly crystalline material [20]. As has been previously indicated, enhanced levels of amorphicity lead to increased local levels of moismre, and increased chemical reactivity in these areas. Hancock and Zografi [49] reported on the impact of a roller-compaction process on the water vapour sorption of a sample of aspirin. They speculated that... 

Kovacova (1990) describes a method for the batch drying of fruit and vegetable pulp in a fluidized bed in which carrier particles (variously crystalline and caster sugar, dried skim milk, potato and wheat starch, apple powder, semolina or oat flakes), pre-moistened to a solids content of between 55% and 76%, are fed to a preheated fluidized bed and sprayed with the pulp to be dried. A product with a narrow particle size distribution and a uniform pulp content is claimed. Specific foods for which fluidized bed granulation has been used include potato puree (Zelenskaya and Filipenko, 1989) and granulated dried apple (Haida et al, 1994). 

Haida, H., Kroyer, G.T., Kuenne, H.J., Washuettl, J. and Winker, N., Anwendung der Wirbelschichttechnologie zur Herstellung eines Apfeltrockenproduktes [Use of fluidized bed drying for manufacture of a granulated dried apple product], Deutsche Lebensmittel Rundschau, 90 (1994) 9-15. 

Powder To avoid accidental inhalation or esophageal distress, do not take powder or granules dry. Mix with fluids. 

Development of solid dosage forms, more specifically tablets, involves three alternate processing methodologies—wet granulation, dry granulation, and direct compression (DC) (1). All these processes share the following common problems ... 

Note If a single piece of equipment is capable of performing multiple discrete unit operations (mixing, granulating, drying), the unit was evaluated solely for its ability to dry. The drying equipment was sorted into similar classes of equipment, based upon the method of heat transfer and the dynamics of the solids bed. 

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