ABSTRACT
The applicability of the spouted bed technique [1-5] to drying of granular products that are too coarse to be readily ¤uidized (e.g., grains) was recognized in the early 1950s. Interest in this area received appreciable impetus two decades later as the energy-intensive drying processes were reexamined with renewed vigor. Spouted bed dryers (SBDs) display numerous advantages and some limitations over competing conventional dryers. Because of the short dwell time in the spout, SBDs can be used to dry heat-sensitive solids, such as foods, pharmaceuticals, and plastics. With simple modication the so-called modied spouted beds can be designed to ensure good mixing, controlled residence time, minimum attrition, and other desirable features. Also, the operations of coating, granulation agglomeration, and cooling, among others, can be carried out by the same apparatus by varying the operating parameters. SBDs can be used for solids with constant
as well as falling rate drying periods. Using inert solids as the bed material, SBDs have been used successfully to dry pastes, slurries, and heat-sensitive materials.
