The effect of temperature on particle entrainment rate in a gas fluidized bed

The qualitative effect of temperature on the particle entrainment rate has been measured in a gas fluidized bed (i.d. 0.1 m, height 1.97 m) equipped with an electric heater, using sand as the bed material. The mean particle size (0.091-0.363 mm), the gas velocity (0.65-2.3 m/s) and the bed temperature (20-600 degrees C) were considered as experimental variables. As the temperature was increased, the particle entrainment rate was observed to decrease initially. However, above a certain temperature it began to increase for gas velocities between 0.8 and 1.4 m/s. The variation of the particle entrainment rate with temperature was similar to that of the particle size for which the terminal velocity is equal to the gas velocity.