2.2. Rotary drum dryer
A rotary drum dryer was designed and built specifically for this
research study (Fig. 1). The main components of the rotary drum
dryer are an electrical heating/fan unit, a rotary drum horizontally
placed on four rubber wheels, a control panel, and an air channel/
distribution room unit. This rotary drum dryer has a cylindrical
drum, 95 cmin outer diameter and 130cm in length. The drum was
constructed of a 1-mm thick perforated chrome–nickel sheet with
2-mm diameter holes (112 holes per 10cm2). Four 30-cm wide
baffles (inner wings) were attached lengthwise inside this drum
evenly distributed around the drum to mix the drying materials
uniformly (Fig. 2). The drum was placed on four rubber wheels
and its bottom faced to the air distribution room. One of the rub-