Answer to Question #344179 in Chemical Engineering for ceyssssuuu

Question

The falling rate portion of the drying time for a particle of skim milk begins at the critical moisture content of 25%, and the final moisture content is 4%. The air used for drying is 120°C and was heated from ambient air of 20°C and 40% RH. The particle size at the critical moisture content is 20 microns, and the specific heat of the product solids is 2.0 kJ/kg K. The mass diffusivity for water within the product particle is 3.7 x 10-12 m2/s, and the density of the product particle is 1150 kg/m3. If the equilibrium moisture content for the product is 3.5%, estimate the time for the falling rate portion of drying. 

b. If 5000 m3/min of heated air is needed for product drying, determine the thermal energy needed to heat the air to 120°C.