Effect of Spirals in an Inclined Bubbling Fluidized Bed Paddy Dryer

Abstract

Present paper deals with the effect of passive inserts and inclination of dryer on drying of cereal grains in a bubbling fluidized bed dryer. Paddy was dried in three different inclined positions, viz., vertical bed (0° inclined), 15° and 30° in a bubbling fluidized bed. Experiments were conducted for 0.5 to 2.5 kg batch size of with superficial velocities of 1.1 m/s and 1.6 m/s. All the experiments were repeated with and without spirals inserts. Results were obtained for air temperature of 55°C, 60°C and 65°C and air velocities of 1.1 ms-1 and 1.6 ms-1 respectively. Better results in terms of energy consumption and moisture removal were observed with bed inclination of 15° due to the secondary motion created due to the pressure difference between the vertical faces of the dryer. Use of spirals enhanced better mixing of paddy, reduces time for drying as well as reduces energy consumption significantly.