Chemical Engineering - Mass Transfer - Discussion

A solid is being dried in the linear drying rate regime from moisture content X_o to X_F. The drying rate is zero at X = 0 and the critical moisture content is the same as the initial moisture X_o. The drying time for M = (L_s/AR_c) is (where, L = total mass of dry solid, A = total surface area for drying R_c = Constant maximum drying rate per unit area X = moisture content (in mass of water/mass of dry solids))