APV Dryer Handbook - Umbc

FOR FOOD PRODUCTS FOR CHEMICAL PRODUCTS
Maltodextrines Lignosulfonates
Gum arabic Poly-vinyl alcohol (PVA)
Starch Any of the food product binders
Gelatin
Molasses
Sugar
Table 4. Frequently used binders
For products containing fat, the normal process is often combined with a step by
which the agglomerates are coated with a thin layer of surface active material,
usually lechithin. This is accomplished by mounting an extra set of spray nozzles
near the end of the drying section where the surfactant is applied.
Variations of the fluid bed re-wet technology have been developed whereby the
system serves as a mixer for several dry and wet products. An example of this
may be seen in the APV fluid mix process for the continuous production of
detergent formulations from metered inputs of the dry and wet ingredients. This
provides an agglomerated end product with minimum energy input when
compared to traditional approaches.
SPRAY BED DRYER AGGLOMERATION
While the fluid bed re-wet agglomeration method produces an excellent product
which is, in most respects, superior to that made directly by the straight-through
process, a new generation of spray dryers has evolved that combines fluid bed
agglomeration with spray drying. These are referred to as “Spray Bed” dryers.
The concept was developed from spray dryers having a fluid bed integrated into
the spray chamber itself and is depicted in Figure 20. What distinguishes the
Spray Bed dryer is that it has the drying air both entering and leaving at the top
of the chamber. Atomization can be with nozzles or by a centrifugal atomizer.
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