Drying Strategy of a Rotary Drum Longan Dryer

Abstract

A batch type rotary drum longan dryer is studied in this research work. A mathematical modelfor dehydration of whole longans to determine appropriate operating conditions of the dryer hasbeen developed. The parameters affecting the drying performances are the drying air temperature,the air flow rate and the drum rotational speed. The experimental results agree very well with thoseof the simulated values. It is found that the appropriate operating condition is achieved when thedrum rotational speed is 0.75 rpm. The drying air temperature is about 95oC when the specific massflow rate of air is less than about 4.3 kg/h-kg dried longan and when the value is over this, the dryingtemperature should be 75oC.