Deep-Bin Drying Characteristics of Unshelled Peanuts

Author(s): Nonilon T. Bulilan and Ernesto P. Lozada


Unshelled peanuts were loaded in a deep-bin dryer at a maximum depth of 182.9 cm. The variations in the temperature and moisture content (M.C.) of unshelled peanuts dried at three drying air temperatures and two air flow rates were studied. Large temperature and M.C. gradients were observed between the upper and lower levels of peanuts in the bin during the first 20 hr of drying after which these gradients gradually decreased. The rate of moisture removal of unshelled peanuts was affected by drying air temperature and air velocity. The higher the drying temperature and the air velocity, the shorter was the drying time. Drying peanuts from 40 to 13% moisture (safe for storage) could be accomplished in at least 48 hr with an air temperature of about 43.3°C and an air flow rate of about 0.0052 cubic meter per second (cmps) per 0.028 cubic meter load. Under specific drying conditions, the rate of drying decreased with an increase in the height of the peanut column. Drying peanuts at a depth of 182.9 cm was found most economical (i.e., requires least energy) without much gradient in moisture at the end of the drying process.

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