Design of recirculated column dryer type for corn (Zea mays Linnaeus) drying

Corn (Zea mays L.) is ussually consumed as food and feed. In post harvest handling, drying process is the most critical step that affect on the quality of corn. One method of drying corn is mechanically using a recirculated batch dryer. However, these dryers has not been widely found in Indonesia. Therefore, research on the design of this type of dryer is needed. The purpose of this research was to design a recirculated batch dryer machine and test its performance. The recirculated batch dryer machine was designed with a capacity of 2000 kg of corn shelled to dry from moisture content 25 to 14 for 8 hours. Feeding system into the drying chamber used a screw feeder. Corn were recirculated in the drying chamber using a vertical screw conveyor. Air heating system was directly using LPG gas fuel. Furthermore, the design results were tested for the performance of drying, feeding and circulation. The design results show that the designed machine has a capacity of 2,000-2,300 kg. The screw feeder capacity was 1,857 kg/hr and the vertical screw conveyor capacity was 2,216 kg/hr. The airflow supplied blower was 4,358 m³/hr. The results of the machine performance test showed a drying rate of 1.55/hr. The efficiency of air heating was 92.03 and the the efficiency of drying was 88.96.