In this dryer design (Fig. 2.2.1), the spray and the air
are introduced at opposite ends of the dryer, with the
atomizer positioned at the top and the air entering at
the bottom. A counter-current dryer offers more rapid
evaporation and higher energy efficiency than a cocurrent
design. Because the driest particles are in
contact with hottest air, this design is not suitable for
heat-sensitive products. Counter-current dryers
normally use nozzles for atomization because the
energy of the spray can be directed against the air
movement. Soaps and detergents are commonly
dried in counter-current dryers.