100kg of granular solid with 30% moisture content (wet basis) is dried to a moisture content of 5% (wet basis) with a tray dryer at 350K temperature and a continuous air flow. Calculate the constant period drying time if the constant drying rate under these conditions is 0.7g/s.m2 and the critical moisture content is 15.5% (wet basis). Consider the drying surface area as 0.03m2/kg dry weight