1000 kg dry weight of non porous solid is dried under constant drying conditions with an air velocity of 0.75 m/s, so that the area of drying surface is 55 m. The critical moisture content of the material may be taken as 0.125 kg water / kg dry solid. (a) If the initial rate of drying is 0.3 g/m.s., how long will it take to dry the material from 0.15 to 0.025 kg water / kg dry solid? (b) If the air velocity is increased to 4.0 m/s, what would be the anticipated saving in time if surface evaporation is controlling? (16) (16) (Nov/Dec '05)