A material was dried in a tray type batch drier using constant drying conditions. When the initial free moisture content was 0.28 kg free moisture / kg dry solid, 6.0 hr was required to dry the material to a free moisture content of 0.08 kg free moisture / kg dry solid. The critical free moisture content is 0.14.. Assuming a drying rate in the falling rate region where the rate is a straight line from the critical point to the origin, predict the time to dry a sample from a free moisture content of 0.33 to 0.04 kg free moisture / kg dry solid. (16) (Nov/Dec '07)