Characteristic of Corn drying (Zea Mays L) using recirculated column dryer

The corn ussually are harvested at high moisture content (more 25 w.b.), therefore at those conditions the corn will be very susceptible to damage such as attacked by fungi, bacteria, or physical damage. Drying using mechanical dryer is must conducted on those product to prevent deterioration. In Indonesia there are few resirculated column batch dryer machines with screw conveyor for circulation, however the information of the performance of this dryer is very limited. The objectives of this research is to determine the characteristic of corn drying using those machine. The material is using sheeled corn that have initial moisture 25-30 (w.b.). The corns were dried using the recirculated column batch dryer that have capasity of 2 tons/batch. The drying chamber has diameter of 2,0 m and the height of 3 m. Heat source of this drryer is from liquid petroleum gas that was delivered by high capacity of centrifugal blower. Drying temperature was controlled using automated thermostat that connectd to the gas pipe. Drying experiment was conducted using 45 oC, 55 oC and 65°C. The measurement of moisture content is used for the determination of the drying rate and the drying efficiency. The quality determination parameters used are bulk density, damage, and cleanliness. The results show that the dryer air temperature affected the drying rate, the efficiency of drying, and the quality of the material. The best drying rate with temperature 65°C average 4,95/hour, high efficiention at dryer temperature 55°C and 65°C equal to 86,27 and 83,51, and best material quality with dryer temperature 55°C.