CHE 304

Transport Phenomena III

 Quiz # 4 

A charcoal briquette, approximately spherical in shape with a 2.54-cm radius, has an initial moisture content of 350 kg/m3.  It is placed in a forced air dryer.  The moisture content of the air inside the dryer maintains a surface moisture content of 12 kg/m3.  If the diffusivity of water in charcoal is 1.3*10-6 m2/s and the surface resistance is negligible, estimate the time required to dry the center of the briquette to a moisture content of 50 kg/m3.